CN101542143A - Shaft member for fluid bearing device and method of producing the same - Google Patents

Abstract

A shaft member for a fluid bearing device, having excellent accuracy in bearing surfaces, having excellent shape accuracy between the bearing surfaces, and having high fixing strength between a shaft section and a flange section. [MEANS FOR SOLVING PROBLEMS] The shaft section (21) is press fitted in the flange section (22), and a plastic processing section (31c) of a first jig (31) is pressed to an upper end surface (22a) of the flange section (22) to partly plastically deform the flange section (22) radially inward. By this, a staked section (23) is formed between the shaft section (21) and the flange section (22). Also, press fitting and staking are performed with both end surfaces (22a, 22b) of the flange section (22) restrained by second and third jigs (32, 33).

Description

Shaft member for fluid bearing device and manufacture method thereof

Technical field

The present invention relates to shaft member for fluid bearing device and manufacture method thereof.

Background technique

Hydrodynamic bearing device is that the film by the fluid that forms in the bearing play rotates the device of supporting shaft part freely relatively.This kind bearing means especially running accuracy when high speed rotating, quietness etc. is good, is applicable to the bearing means that the motor that carries on the various electrical equipments based on information equipment is used.Specifically, be applicable to the bearing means of using as the spindle motor in magneto-optical disc apparatus such as optical disk unit such as disk device, CD-ROM, CD-R/RW, DVD-ROM/RAM, MD, MO such as HDD etc., perhaps be applicable to the motor bearing means such as color wheel motor, fan motor of multiaspect scanner motor as laser beam printer (LBP), projector.

Usually, in hydrodynamic bearing device, the axial region of spindle unit inserts week in the bearing sleeve etc., formation radial bearing portion between the inner peripheral surface of the outer circumferential face of axial region and bearing sleeve.In addition, following hydrodynamic bearing device is arranged, that is: the end at axial region is provided with lip part, constitutes thrust bearing portion (for example with reference to open communique 2003-239951 number of Japan's special permission) between the end face of this lip part and the face relative with it (for example end face of bearing sleeve).

So, the outer circumferential face of axial region constitutes radial bearing portion, and in addition, the end face of lip part constitutes thrust bearing portion, therefore, needs this face of fine finishing accurately.Simultaneously, under the common situation that constitutes radial bearing portion and thrust bearing portion, each surface accuracy not only, is that squareness between the end face of the outer circumferential face of axial region and lip part becomes important at the accuracy to shape between them.

As with separate axial region and the incorporate accurately method of lip part, for example propose to have by thrust plate to be pressed into stationary axle and fixing method (for example opening communique 2001-317545 number) with reference to Japan's special permission open communique 2000-324753 number or this state special permission spy with ring-type.

In addition, as being pressed into the axial region of fixing other and the mechanism of lip part accurately, proposition has following scheme, that is: used high-precision processing in advance axle maintenance face and the guide element that encircles the squareness between the bearing surface, and, the lower end periphery that use will be pressed into the spindle unit (axial region) of mutual butt of when beginning is provided with R portion (chamfered section), and the parts that the upper end inner circumference edge in the hole of ring portion (lip part) is provided with chamfered section are pressed into fixing (for example with reference to open communique 2001-287124 number of Japan's special permission).In this case, the R portion that at first is arranged at the lower end of spindle unit contacts with the chamfered section in the hole of ring portion, utilizes its effect, and ring portion moves in the horizontal direction, is pressed in that spindle unit and ring portion are aligned under the coaxial state.

In addition, recently,,, need to improve for patience (impact resistance) such as falling for the hydrodynamic bearing device that is equipped on these information equipments along with the miniaturization of information equipment, the development of portability.Thereby if with axial region and the independent spindle unit of constructing of lip part, it is important improving its fastening strength.

As the method that is used to improve fastening strength, proposition has following method: for example under the air-tight state of the expansion of the outer diameter part of limit flange element, lip part is axially pressurizeed, make the reduced of the inner peripheral surface of lip part, thus, fastening fixing (for example with reference to open communique 2004-204916 number of Japan's special permission) of realization and axial region.

Patent documentation 1: open communique 2003-239951 number of Japan's special permission

Patent documentation 2: open communique 2000-324753 number of Japan's special permission

Patent documentation 3: the special permission spy of Japan opens communique 2001-317545 number

Patent documentation 4: open communique 2001-287124 number of Japan's special permission

Patent documentation 5: open communique 2004-204916 number of Japan's special permission

Be pressed into other means of fixation and compare and to implement with comparalive ease, in addition,, then can become the method for guaranteeing assembly precisions such as squareness as long as high-precision processing is pressed into fixing face mutually and implements the location in advance.But as mentioned above, aspect fastening strength, the retention force (anticreep power) that is possessed such as to fall be inadequate for requiring to improve.And, recently strong for the requirement of miniaturization, if dwindle shaft size, then have to shorten being pressed into length.Thereby, be difficult to guarantee fastening strength.Record after being pressed in the patent documentation 2,, realize the enhancing of constant intensity, but this kind operation needs equipment extensive and high price in addition, causes manufacture cost to improve by the axial end portion of this embedding area of laser bonding.

Perhaps, as the record of patent documentation 5, adopted following method, that is: the lip part of the state of the expansion by will being limited outer circumferential face by so-called punch process compression undergauge is realized the fastening of axial region and lip part.Under the situation that has adopted this method, the precision aspect has problems.That is, lip part is the parts with bearing surface, needs the high lip part of its accuracy to shape or surface accuracy.In addition, this kind fixation method is fastening fixing by the whole plastic deformation of parts is realized, therefore is difficult to avoid distortion such as bearing surface, and the problem of necessary surface accuracy can not be fully guaranteed in existence.

In addition, as mentioned above, be pressed under the incorporate situation that realizes axial region and lip part, if the accuracy to shape (squareness) between the raising bearing surface is pressed into size (the axial length that is pressed into) as long as increase in utilization.But under the nearest situation strong for the requirement of miniaturization, the axle direction size that is difficult to avoid dwindling spindle unit, it is very difficult that increase is pressed into size.

In addition, as described in patent documentation 3, under the situation that adopts method of press-fitting, only set magnitude of interference and can access higher constant intensity.On the other hand, because constant intensity has opposite relation with assembly precision, therefore cause increasing more and requiring the corresponding magnitude of interference of raising anti-avulsion power (retention force), cause the reduction of assembly precision more, thus, be difficult to obtain needed accuracy to shapies such as squareness between bearing surface.

And by being pressed under the situation of guaranteeing fastening force, described fastening force exists with ... the state (size, uniformity) of magnitude of interference more greatly.Thereby, in order not obtain high fastening force unevenly, have only the machining accuracy (dimensional accuracy) that improves each parts, but some parts since with other the equilibrium at position (for example thrust shaft bearing surface) etc. that requires high-precision processing, be difficult to high-precision processing sometimes.Especially at the place, hole of the outer circumferential face of axial region and lip part, because its processing method difference, so machining tolerance (tolerance of size) difference, so become big by the inequality of the magnitude of interference that difference produced of this tolerance.Thus, produce the assembling that actual magnitude of interference departs from its permissible range sometimes, existence can't obtain the anxiety of needed fastening force.

In addition, become volume production product, the inequality on the size of axial region that allows manufacturing separately to a certain degree and lip part of having to if consider this kind spindle unit.Under the situation of prerequisite, as patent documentation 4, even use the guide element in advance axle is kept after face and the squareness high-precision processing of encircling between the bearing surface to be pressed into, also be difficult under the state of keeping accurately with respect to the position of the lip part of axial region or posture, be pressed into.

In addition, be the distortion of following mutual parts owing to be pressed into, therefore,, follow the carrying out that is pressed into even when being pressed into beginning, locate accurately, produce its position and concern that ruined situation is quite a few.Patent documentation 4 described guide elements are connected in driving mechanism (thread spindle) via spring, though therefore axial region be pressed into beginning, guide element constitutes unlike the position with the lip part butt and more descends.But this guide element only carries out the location of lip part with respect to axial region when being pressed into beginning, is not skew or the reparation that is used to prevent to be pressed into the position relation after the beginning.

In view of the foregoing, first purpose of the present invention is to form the precision of bearing surface and the accuracy to shape between bearing surface at low cost, and has the spindle unit that the hydrodynamic bearing device of high constant intensity is used between axial region and the lip part.

In addition, in view of above situation, second purpose of the present invention provides a kind ofly can guarantee assembly precision between axial region and lip part, and can not obtain the manufacture method of the shaft member for fluid bearing device of needed fastening strength unevenly.

In addition, in view of above situation, the 3rd purpose of the present invention is the precision of volume production bearing surface at low cost and the spindle unit that the good hydrodynamic bearing device of the accuracy to shape between bearing surface is used.

Summary of the invention

The solution of described first technical problem is realized by the shaft member for fluid bearing device of first side of the present invention.Promptly, this shaft member for fluid bearing device possesses axial region and is fixed in the lip part of an end of axial region, and between the outer circumferential face of axial region and the face relative, form the radial bearing gap with this outer circumferential face, and between the end face of lip part and the face relative, form the thrust bearing gap with this end face, and by in the radial bearing gap and the film of the fluid that forms of thrust bearing gap come the described shaft member for fluid bearing device of swivel bearing, be characterised in that, axial region is pressed into the hole portion that is arranged at lip part, and a side of axial region and lip part partly is subjected to plastic working and ca(u)lk is fixed in the opposing party.

So, the spindle unit of first side of the present invention with will be pressed into fixing and ca(u)lk fixedly acting in conjunction this as feature, and the ca(u)lk that forms with the plastic deformation of avoiding by lip part integral body, to form this point of ca(u)lk portion be feature by axial region or lip part being implemented partly plastic working.According to described structure, can avoid as produced the distortion of axial region or lip part integral body by ca(u)lk in the past.In addition, form ca(u)lk portion, avoid the zone that is pressed into lax and keep the state of being pressed into by plastic deformation partly.Therefore, under keeping the high surface accuracy state that obtains when being pressed into the high accuracy to shape (squareness) that obtains or each component processing, can realize the raising of constant intensity.Perhaps, under the prerequisite of the constant intensity of need guaranteeing,, also can realize the miniaturization of hydrodynamic bearing device by dwindling its axial dimension.

Ca(u)lk quality award from the ministry gating is crossed lip part is implemented plastic working partly and formed, and in addition, preferably more implements the ca(u)lk portion that plastic working obtains by the zone of internal side diameter by contrast towards the zone in thrust bearing gap.This be because: axial region utilizes the raising of surface treatments such as quenchings realization hardness usually from the viewpoint that intensity improves and sliding properties improves, but lip part compare with axial region, can be by the material of excellent processability.In addition, make lip part plastic deformation partly, the precision of the both ends of the surface that become the thrust shaft bearing surface is worsened if avoid the thrust shaft bearing surface.In addition, can leave in fact as the thrust shaft bearing surface and work the zone and carry out plastic deformation, irrelevant with the minimizing of bearing area, so preferred.

And then, to guarantee that bearing surface precision and its area are purpose, also can be provided with the portion of overflowing at axial region, the portion of overflowing is used to make the plastic deformation of the lip part that is produced by plastic working to overflow to internal side diameter.That is, as mentioned above, when lip part is implemented plastic working (ca(u)lk processing), the minor diameter part of groove shape etc. is set by the position of overflowing in the plastic deformation zone that lip part is produced, plastic deformation produces towards described groove shape minor diameter part.Therefore, be suppressed at the protuberance of the area peripheral edge of having implemented plastic working, and can maintain the precision of the thrust shaft bearing surface that lip part do not put.

In addition, the present invention also can carry out above-mentioned ca(u)lk processing to the portion of overflowing that week is provided with in an end face of lip part.As shown in figure 23, make be pressed into to the processing acting in conjunction of the ca(u)lk of lip part and lip part 122 is fixed under the situation of axial region 221, be formed with the ca(u)lk that is subjected to being undertaken at the end face 222a of lip part 222 and process and the part (recess 222f) of depression, and around recess 222f, produce ridge 222g (with reference to Figure 23 B) accordingly with amount of recess by the 131b of plastic working portion.Therefore,, especially under the ridge 222g that the area side near the thrust shaft bearing surface of the end face 222a that becomes lip part 222 the forms situation more outstanding, there is pair bearing performance to cause the anxiety of harmful effect from this bearing surface at this ridge 222g, not preferred.Particularly to the implementing in interior week under the situation of ca(u)lk processing of the lip part that is in the state of being pressed into, the plastic deformation that is processed to form by ca(u)lk has not to the axial region side and the tendency that produces to the outside diameter of lip part, and therefore above-mentioned protuberance is remarkable.

Be directed to this,, and this portion of overflowing carried out ca(u)lk processing, then form recess, and the plastic flow that is produced by ca(u)lk processing is absorbed by the portion of overflowing adjacent with this recess in the part that is subjected to ca(u)lk processing if in an end face of lip part, week the portion of overflowing is set.Thereby, can be suppressed to the ridge that produces near thrust shaft bearing surface side lower.In addition, implement ca(u)lk processing as if the position that the external diameter end from the portion of overflowing is left, the ridge that is produced at its outside diameter by ca(u)lk processing is formed in the portion of overflowing.Therefore, can be suppressed to lower from the outstanding part of thrust shaft bearing surface the ridge that is produced by ca(u)lk processing.In addition, in this case, can will be suppressed to lower from the outstanding height of above-mentioned thrust shaft bearing surface according to ca(u)lk amount of finish (size of recess).Specifically, ridge is made as below the 3 μ m, more preferably below the 2 μ m, can avoids the interference to the essence of bearing performance, and guarantee good bearing performance from the projecting height of thrust shaft bearing surface.

In addition, by the size (particularly its height) of adjusting the ridge that is produced by ca(u)lk processing, also the ridge (first ridge) that can be produced by the outside diameter of the part of depression being subjected to ca(u)lk processing constitutes the thrust shaft bearing surface.That is, cooperate the size of overflowing part adjacent in the portion, be adjusted at the size of the ridge of thrust shaft bearing surface side generation, described ridge can be used as the part of thrust shaft bearing surface with the thrust shaft bearing surface.Thereby, can from axial region distant from the position lip part end face is implemented ca(u)lk processing, thus, can further strengthen ca(u)lk to axial region.And the height of the protuberance that is produced by ca(u)lk processing can wait with front end shape, the ca(u)lk amount (amounts of being pressed into of anchor clamps) of anchor clamps or the shape of overflowing portion and controls by the suitable ca(u)lk for example set.

In addition, the internal side diameter of the part of depression forms under the situation of ridge being subjected to ca(u)lk processing, also can be formed and the ca(u)lk portion of axial region by this ridge (second ridge).Under this situation, ridge big more (high more) increases with the fastening area of axial region, therefore initiatively makes internal side diameter produce plastic deformation by above-mentioned adjustment, can improve thus by ca(u)lk generation with retention force axial region.

So, be pressed into and the ca(u)lk acting in conjunction by making,, can be fixed the also good spindle unit of good strength and assembly precision by lip part is fixed in axial region, but under described situation, need be careful because ca(u)lk processing encourages this point of anxiety of the distortion of the lip part when being pressed into.That is, in that axial region is fashionable from any side pressure in the hole of lip part, sometimes according to the machining accuracy in the hole of lip part how, and magnitude of interference produces unevenly in the axial direction, and lip part produces the situation of warpage on either direction.If the warpage of possessing this kind is implemented ca(u)lk processing to an end face of lip part, the anxiety of the warpage (distortion) of encouraging lip part is then arranged, not preferred.

Be directed to this, in the present invention, between the outer circumferential face of the inner peripheral surface of the hole of lip part portion and axial region,, be provided with the part that the plastic deformation of following ca(u)lk is absorbed except being pressed into the fixing part of fixing part and ca(u)lk.Perhaps, portion is pressed into axial region to the hole of the lip part with large-diameter portion, between the large-diameter portion of hole portion and axial region, form the gap, and all sides are implemented ca(u)lk processing in the end face to lip part, and utilize the distortion that produces by ca(u)lk processing to fill at least a portion in gap.So, during the assembling of axial region and lip part, the part of the distortion that inside at least all sides produce in the plastic deformation of the lip part that is produced by ca(u)lk processing is absorbed between axial region and the lip part.Perhaps, the distortion of lip part produces on the direction in the gap of filling the position setting that should become the ca(u)lk fixing part.Below as can be known, do not cut off inside all sides distortion and the distortion that reduces to produce, can suppress to encourage distortion in the whole warpage that produces of lip part etc. by ca(u)lk to outer circumferential side.

The absorption portion of plastic deformation can form by being filled in the gap that is provided with between lip part and the axial region, and this gap can form being pre-formed between the outer circumferential face of the large-diameter portion of the inner peripheral surface of the hole of lip part portion (hole) and axial region.

At this, the formation position in gap is not specially limited, and for example, can the gap be set in the inboard mode that forms the absorption portion of plastic deformation of the radial direction of the sunk part that is produced by ca(u)lk processing yet.Perhaps, in the mode that under the sunk part that produces by ca(u)lk processing, forms the absorption portion of plastic deformation the gap is set.But, under any situation,, nearer with the distance needs at the position (recess) of implementing ca(u)lk processing in order to absorb the distortion of the lip part that is processed to form by ca(u)lk.In addition, if consider to implement the position of ca(u)lk processing be arranged on as possible with double the closing of thrust shaft bearing surface in this point of all sides, be preferably placed at the radial direction inboard of recess, and the gap be set in the position that this position is filled in the distortion that utilization follows ca(u)lk to process.In this case, the absorption portion of ca(u)lk fixing part and plastic deformation is formed on the same area.According to described structure, as far as possible ca(u)lk processing is implemented in the inboard of lip part, and reduce the distortion that produces by ca(u)lk as far as possible, and, form the same bonding part of ca(u)lk by the filling part in gap and between the axial region, can obtain the retention force that produces by ca(u)lk effectively.

And the ca(u)lk previous crops is the shape in the gap that should form between lip part and axial region, for example can enumerate by the tubular face than the bigger footpath of the portion that is pressed into of hole portion to constitute the large-diameter portion of lip part, and form the gap between the outer circumferential face of this tubular face and axial region.Perhaps, the undercut groove that can enumerate by ring-type constitutes large-diameter portion, and forms the gap between the outer circumferential face of this undercut groove and axial region.

In addition, be purpose with the protuberance that is suppressed on the end face that ca(u)lk adds man-hour, also can in a side's of lip part end face, all side settings overflow portion, and this portion of overflowing is implemented ca(u)lk processing.By forming this kind structure, form recess in the part that is being subjected to ca(u)lk processing, and the plastic flow that produced of ca(u)lk processing is by adjacent with recess and absorb in the portion of overflowing of end face setting.Thereby, the ridge that is produced near thrust shaft bearing surface side can be suppressed for lower.In addition, implement ca(u)lk processing as if the position that the external diameter end from the portion of overflowing is left, the ridge that is produced at its outer circumferential side by ca(u)lk processing is formed in the portion of overflowing.Therefore, the ridge that ca(u)lk processing can be produced suppresses for lower from the outstanding part of thrust shaft bearing surface.

Also have, be pressed into ca(u)lk fixedly in the structure of the present invention of axial region and lip part following, follow ca(u)lk processing (plastic working), the protuberance of wall etc. takes place, this is sometimes especially to the precision generation bad influence in thrust bearing gap.Example as the scheme of avoiding described bad influence, consideration is after ca(u)lk processing, implement machinings such as cutting, remove the protuberance of wall, but reduction for fear of the dirty bearing performance that causes, also need and then be provided with to be careful the operation of removing the cutting powder of following cutting and producing, cause manufacture cost to increase.

At this, for example, cover lip part with covering part with the thrust bearing clearance plane to the situation of end face under, only through forming an operation of covering part, just can get rid of the bad influence that the protuberance etc. of wall causes, form high-precision thrust bearing gap.In addition, even be pressed into or ca(u)lk following, under the shape of axial region and lip part or the situation of relative posture variation, also can enough covering part guarantee necessary accuracy.In other words, can not produce in the scope of bad influence, relax parts and makes, be pressed into, reach the quality that requires in each manufacturing procedure of ca(u)lk bearing performance.Therefore, also realize cheapization of manufacture cost from this respect.

Ca(u)lk is also harmless to the either party of axial region or lip part or two sides enforcement, but wishes lip part is implemented.This be because, axial region utilizes surface treatments such as quenchings to come high hardnessization from the viewpoint that intensity improves or the slip mobility improves usually, with respect to this, lip part can be formed by the processability material more superior than axial region.

From the viewpoint of high precision int covering part at low cost, covering part wishes to embed axial region and lip part and contour forming.In addition, in covering part the thrust dynamic pressure generating section that the axial thrust bearing gap produces hydrodynamic can be set.Especially, under the situation of contour forming covering part, can obtain guaranteeing the spindle unit of expected accuracy at low cost, and can be with the formation of covering part the time, contour forming thrust dynamic pressure generating section.Therefore, labour and time that dynamic pressure generating section is set at the parts of the opposite side that forms the thrust bearing gap can be saved, the cost degradation of hydrodynamic bearing device can be realized.

Also have, about the spindle unit in the above explanation, the hole portion that is arranged at lip part form concavity also can, form at the through hole of both ends of the surface opening and also can.Especially, form under the latter's the situation of structure, can form ca(u)lk portion, therefore, be fit to realize the high strength of spindle unit at the two ends of hole portion.

In addition, the solution of described first technical purpose is that the manufacture method of the shaft member for fluid bearing device by first side of the present invention realizes.Promptly, the manufacture method of this spindle unit is to possess axial region, with the lip part of fixing at an end of axial region, the outer circumferential face of axial region and and opposed of this outer circumferential face between form the radial bearing gap, and, the end face of lip part and and opposed of this end face between form the thrust bearing gap, utilization is in the radial bearing gap and the film of the fluid that forms of the thrust bearing gap manufacture method of coming rotatably supported shaft member for fluid bearing device, it is characterized in that, axial region is pressed into the operation of the hole portion of lip part setting, on operation this point with axial region or lip part ca(u)lk.

According to such manufacture method as can be known, be useful in this column beginning narration about the item of spindle unit and identical item, therefore, can access with based on the identical action effect of the action effect of this item.

At this, ca(u)lk processing is both either party of parts of fastening strength plastic deformation to take place usually, therefore, for example, after being pressed into operation, carry out under the situation of ca(u)lk operation, because the plastic deformation of a side parts, participation is pressed into fixing zone and deforms, and may cause the reduction of the power that is pressed into or be pressed into the reduction of precision.At this, for example, under state, be pressed under the situation of the ca(u)lk operation under the state, can keep the surface accuracy of the end face of constraint two sides' of lip part end face constraint, in addition, will be maintained with respect to the posture (position) of the lip part of axial region under the original state when being pressed into and carry out ca(u)lk.In addition, using fine finishing is that high-precision anchor clamps come under the situation to the face ca(u)lk of containment flange portion, can correct position deflection when being pressed into etc. by the constraint of anchor clamps.In addition, can with fixing in make spindle unit with high accuracy to shape (squareness etc.), therefore, in the processing of back, do not need the operation that is used to correct separately, do not increase process number and can yet.Thus, according to this method as can be known, can have very high surface accuracy and squareness, and have the spindle unit of sufficient fastening strength with the low cost manufacturing.

Certainly, when being pressed into operation, also form the state of two sides' that retrained lip part end face, can be pushed down at the state that is pressed into posture that has suitably kept axial region thus with respect to lip part.In addition, under the situation that the state that has suitably kept being pressed into posture is pushed down into, the possibility of the position deflection after being pressed into is few, therefore is fit to.

In addition, the purpose of the skew of the tolerance of size that produces from axial region and lip part, separately manufacturing procedure for compensation, the power that is pressed into that also can be when axial region is pressed into lip part is set ca(u)lk power.In this case, become constant mode so that be pressed into the summation of the retention force that the retention force that causes and ca(u)lk cause, based on can formerly detect be pressed into the time load (being pressed into power), the load the during ca(u)lk that carries out after being controlled at (ca(u)lk power).Perhaps, be set at, give certain ca(u)lk power as required, implement ca(u)lk and process so that the summation of retention force (constant intensity) satisfies the mode of the constant intensity of the minimum that requires according to its purposes etc. often.Therefore, exist under the discrete situation even go up in poor (being equivalent to magnitude of interference) of the internal diameter in the hole of the external diameter of the axial region that is pressed into mutually and lip part, also the retention force of axial region that finished product is had and lip part remains constantly, or guarantees its minimum.Thus, can improve yield rate, high-quality spindle unit stably is provided.

The spindle unit of first side of the invention described above or utilize the spindle unit of its manufacture method manufacturing to have very superior bearing surface precision and the squareness between the bearing surface, therefore, can be suitable as and to manage the shaft member for fluid bearing device of bearing play accurately, or the hydrodynamic bearing device that possesses this spindle unit provides.In addition, the HDD that can pack into waits in the motor that miscellaneous part forms and suitably provides at the end of the opposition side of the lip part of axial region mounting disc drum with motor etc.

In addition, the solution of described second technical purpose is that the manufacture method of the shaft member for fluid bearing device by second side of the present invention realizes.Promptly, the manufacture method of this spindle unit be possess outer circumferential face towards the axial region in radial bearing gap and be fixed in an end of axial region and at least one side's end face towards the manufacture method of the shaft member for fluid bearing device of the lip part in thrust bearing gap, it is characterized in that, the hole portion that is included in the lip part setting is pressed into the operation of axial region, the operation of the magnitude of interference when estimating being pressed into of axial region and lip part and based on the magnitude of interference of estimating, and sets on the operation this point of the ca(u)lk condition after being pressed into.

Like this, the manufacture method of second side of the present invention is characterized in that, axial region is pressed into lip part, and, estimate the magnitude of interference when being pressed into, based on the magnitude of interference of estimating, set on the ca(u)lk condition this point.According to described method as can be known, can regulate the ca(u)lk condition, therefore, can compensate the discrete of magnitude of interference, stable retention force is given between axial region and lip part by ca(u)lk according to the size of the magnitude of interference of estimating.Especially, under the situation of magnitude of interference less than the value of suitable magnitude of interference of evaluation, come under suitable ca(u)lk condition, to implement ca(u)lk processing, make reinforcement have substance and effective thus based on ca(u)lk based on the value of the magnitude of interference of estimating.Certainly, be speculated as under the situation of utilizing the magnitude of interference that is pressed into the fastening force of guaranteeing needs, can setting the ca(u)lk condition of omitting ca(u)lk processing.

In addition, consider productivity and cost aspect usually and implement above-mentioned assembling procedure (realizing the incorporate operation of axial region and lip part) with the group unit.In this case, being pressed into operation is to implementing from axial region and the optional one group of axial region of lip part group separately and lip part.Like this, implementing under the situation of assembling procedure, for example, shown in Figure 60, (among Figure 60, using the zone for scope at effective and suitable magnitude of interference with the group unit _A0The scope of expression) comprise in as much as possible axial region and the purpose of lip part, consider with group L _s, L _fUnit carries out the representative outside dimension M with axial region _sRepresentative internal diameter size M with the hole of lip part _fDifference as the P of the desired value of magnitude of interference _Aim'sCoupling.

Yet, if on the basis of having carried out such coupling, implement to be pressed into, in assembling part, comprise and belong to the too small scope of magnitude of interference and (among Figure 60, use regional A ₁The expression scope) or the excessive scope of magnitude of interference (among Figure 60, use regional A ₂The scope of expression) assembling part.Under the too small situation of magnitude of interference, as mentioned above, can come ca(u)lk according to the size of the magnitude of interference of estimating, compensate retention force thus, but under the excessive situation of magnitude of interference, the unfavorable condition of the inner-diameter portion whose of generation cutting lip part etc., the unfavorable condition that generation can not utilize ca(u)lk to compensate, its result causes the reduction of yield rate.

Therefore, in the present invention, before being pressed into operation, carry out to be set at the little coupling of desired value of magnitude of interference by the difference of the representative internal diameter size of the hole portion of the representative outside dimension of the axial region of each group regulation and lip part, then, implement to be pressed into operation with the group unit.Also have, " representative outside dimension " described herein comprising: the mean value of the outside dimension of all axial regions that comprise in the unit group (mean outside diameter size) or with the outside dimension of the axial region size as the number of degrees the highest (ratio that comprises in the group is the highest) under the situation of observing that distributes with the number of degrees of organizing unit.Also comprise same notion about " representative internal diameter size ".

The permissible range of suitable magnitude of interference has certain width of the desired value that comprises magnitude of interference usually, and therefore, as mentioned above, unit mates with group, and the permissible range of suitable thus magnitude of interference shifts to the big side of interference quantitative change on the whole.Its result, though the too small relatively scope of magnitude of interference (scope that a side that diminishes to magnitude of interference from the permissible range of suitable magnitude of interference breaks away from) increases, the excessive relatively scope of magnitude of interference (scope that breaks away to the big side of interference quantitative change from the permissible range of suitable magnitude of interference) correspondingly reduces.At this, about with the relevant assembling part of mistake combination among a small circle of magnitude of interference, can be by magnitude of interference based on evaluation, carrying out ca(u)lk processes and regulates its retention force, therefore, the retention force after can guaranteeing to assemble to workpiece as much as possible, and, the ratio of the excessive assembling reject that causes of magnitude of interference can be reduced, yield rate can be improved.

In addition, as mentioned above, under the group unit situation of mating, preferably carrying out will be by the difference of the minimum diameter size of the hole portion of the minimum outer diameter size of the axial region of each group regulation and the lip part coupling as the desired value of magnitude of interference.Also have, " minimum outer diameter size " described herein is meant: minimum basically outside dimension in the outside of the axial region that comprises in the group.Equally, " minimum diameter size " is meant: minimum basically internal diameter size in the internal diameter size of the hole portion (hole) of the lip part that comprises in the group.Under the clear and definite situation of nominal size (representative size) or machining tolerance, can be worth by these and infer.

Like this, on the basis of difference as the coupling of the desired value of magnitude of interference of having carried out with the minimum diameter size of the hole portion of the minimum outer diameter size of axial region and lip part, be pressed into, can remove the excessive relatively scope of magnitude of interference (scope that breaks away to the big side of interference quantitative change from the permissible range of magnitude of interference) thus.In other words, in the combination of any axial region and lip part, also can get rid of the state that magnitude of interference breaks away to excessive side from its permissible range.Thereby, can and then reduce and be pressed into relevant assembly failure, can further improve yield rate as spindle unit.

At this,, for example, can enumerate method that the method estimated based on the internal diameter size of the hole portion of the outside dimension of the axial region of measuring before being pressed into and lip part or the load when being pressed into estimate etc. as the evaluating method of magnitude of interference.At this, under the situation that the load when being pressed into is estimated, can be pressed into product according to each, obtain being pressed into the relevant information of state with it, therefore, can estimate magnitude of interference (be inferred as and utilize the fastening force that is pressed under the situation about obtaining) based on the information that has reflected indivedual concrete states that are pressed into.In addition, on the anchor clamps that use etc. suitable pressure transducer only is set and just can individually estimates when being pressed into, therefore, also do not need to measure the operation and the equipment of each size separately, the Economy aspect also is fit to.

In addition, as magnitude of interference based on evaluation, set the method for ca(u)lk condition, for example, can enumerate the lower limit of the magnitude of interference that setting should estimate, under the situation of the magnitude of interference of actual evaluation less than predefined lower limit, be certain value with the ca(u)lk condition enactment, carry out the ca(u)lk method for processing or so that become constant mode based on the fastening force of the interference of estimating and the summation of the fastening force that ca(u)lk causes, the method for setting ca(u)lk condition etc.Wherein, according under situation, be certain value with the ca(u)lk condition enactment less than predefined lower limit, carry out the ca(u)lk method for processing as can be known, can carry out the ca(u)lk operation in single mode (for example, certain ca(u)lk load) by each group, thus practical.Also have, concrete example as the ca(u)lk condition, can enumerate at ca(u)lk and add man-hour, the counter-force that ca(u)lk is subjected to from workpiece with anchor clamps is loaded as ca(u)lk and is estimated, and controls the ca(u)lk method for processing or the method controlled with the amount of being pressed into of anchor clamps with ca(u)lk etc. with the maximum value of described counter-force.

In addition, the solution of described the 3rd technical purpose is that the manufacture method of the shaft member for fluid bearing device by the 3rd side of the present invention realizes.Promptly, the manufacture method of this spindle unit be possess axial region and, be pressed into the lip part of an end that is fixed in axial region, outer circumferential face at axial region, and and opposed of this outer circumferential face between form the radial bearing gap, and, end face at lip part, and and opposed of this end face between form the thrust bearing gap, be used in the manufacture method that the film of the fluid that radial bearing gap and thrust bearing gap form comes rotatably supported shaft member for fluid bearing device, it is characterized in that, be provided with after being pressed into axial region, will be used to correct the operation this point of giving at least one side of axial region and lip part with respect to the corrective force of the posture of the lip part of axial region in the hole of lip part setting portion.

Perhaps, the manufacture method of this spindle unit is to possess axial region, with the lip part that is pressed into an end that is fixed in this axial region, outer circumferential face at axial region, and and opposed of this outer circumferential face between form the radial bearing gap, and, end face at lip part, and and opposed of this end face between form the thrust bearing gap, be used in the manufacture method that the film of the fluid that radial bearing gap and thrust bearing gap form comes rotatably supported shaft member for fluid bearing device, it is characterized in that, to being pressed in the process of axial region, will being used to correct with respect to the corrective force of the posture of the lip part of axial region and giving this point at least one side of axial region and lip part in the hole of lip part setting portion.

As mentioned above, the manufacture method of the 3rd side of the present invention is characterized in that, the axial region and the lip part that are in process of press in or are pressed into done state are corrected.That is, avoid being pressed into when beginning, carried out the stage that is pressed into to a certain degree or be pressed under stage of end correcting, can suitably correct thus owing to being pressed into the crooked etc. of the distortion that takes place or posture.Therefore, it is superior to be manufactured on the precision of the bearing surface that axial region or lip part be provided with low cost, in addition, and the superior shaft member for fluid bearing device of squareness of the bearing surface of axial region and the bearing surface of lip part.

In addition, if after being pressed into end, give corrective force, then can make the mechanism that during being pressed into, uses and correct in the mechanism that uses independently.Hence one can see that, can be under the situation that is not subjected to the restriction that the power that is pressed into causes, with the corrective force of the size that is fit to correct (for example, be pressed into that required load equates or than its big load) give to lip part etc., can improve the degrees of freedom of the form of loading.

In addition,, then can in same operation, be pressed into and correct, thus, can realize the reduction of process number if in the process that is pressed into, give corrective force.In addition, in the configuration aspects of device, the drive system that is pressed into (driving mechanism) that is supplied in axial region can be used (dual-purpose) as the drive system of the rectification that is used in lip part etc., drive system can be one.Therefore, can realize the simplification of necessary equipment.In addition, under the situation of described method, be pressed into midway, correcting posture with respect to the lip part of axial region, therefore, can be by the little state rectification down of the distortion that is pressed into generation (from suitable position crooked).Thereby, can be to correct than being pressed into the little corrective force of giving after the end of situation.

Give in process of press under the situation of corrective force, for example, follow the progress that is pressed into, bar can also be corrected the posture with respect to the lip part of axial region thus to the corrective force that at least one side of axial region and lip part gives gradually.Follow corrective force, under the situation about being pressed into, also depend on rectification mode or its size, can increase sometimes but be pressed into required power.To this, as mentioned above, when improving the corrective force to lip part gradually, under the situation about being pressed into, can reduce to be pressed into required power on the whole.

Under the situation of the spindle unit that the manufacture method of utilizing above-mentioned the 3rd side obtains, squareness between bearing surface precision and the bearing surface is superior, in addition, the property produced in batches is also good, therefore, be suitable as and manage the shaft member for fluid bearing device of bearing play accurately, or the hydrodynamic bearing device that possesses this spindle unit provides.

As mentioned above, according to the shaft member for fluid bearing device of first side of the present invention or its manufacture method as can be known, fix by share to be pressed into to fix with ca(u)lk, lip part is fixed in axial region, can form at low cost bearing surface precision, and bearing surface between accuracy to shape superior, and have the shaft member for fluid bearing device of high constant intensity between axial region and the lip part.

In addition, as mentioned above, according to the manufacture method of the shaft member for fluid bearing device of second side of the present invention as can be known, can between axial region and lip part, guarantee assembly precision in, the fastening strength that needs does not obtain unevenly.

In addition, as mentioned above, according to the shaft member for fluid bearing device of the 3rd side of the present invention or its manufacture method as can be known, by giving corrective force to the axial region or the lip part that are in process of press in or are pressed into done state, can produce in batches at low cost bearing surface precision, and bearing surface between the superior shaft member for fluid bearing device of accuracy to shape.

Description of drawings

Fig. 1 is the sectional drawing of spindle motor that possesses the hydrodynamic bearing device of first mode of execution of the present invention.

Fig. 2 is the sectional drawing of hydrodynamic bearing device.

Fig. 3 is the sectional drawing of bearing sleeve.

Fig. 4 is the planimetric map of bearing sleeve and lip part opposing end faces.

Fig. 5 is the sectional drawing of an example of the conception manufacturing process that represents spindle unit.

Fig. 6 is the sectional drawing of an example of the conception manufacturing process that represents spindle unit.

Fig. 7 is the sectional drawing of an example of the conception manufacturing process that represents spindle unit.

Fig. 8 is the sectional drawing of an example of the conception manufacturing process that represents spindle unit.

Fig. 9 is the sectional drawing of an example of the manufacturing process of the conception spindle unit of representing other modes.

Figure 10 is the sectional drawing of an example of the manufacturing process of the conception spindle unit of representing other modes.

Figure 11 is the sectional drawing of an example of the manufacturing process of the conception spindle unit of representing other modes.

Figure 12 is the sectional drawing of hydrodynamic bearing device of other structure.

Figure 13 is the sectional drawing of spindle motor that possesses the hydrodynamic bearing device of second mode of execution of the present invention.

Figure 14 is the sectional drawing of hydrodynamic bearing device.

Figure 15 is the sectional drawing of bearing sleeve.

Figure 16 is the planimetric map of bearing sleeve and lip part opposing end faces.

Figure 17 is the sectional drawing of an example of the conception manufacturing process that represents spindle unit.

Figure 18 A is utilizing plastic working portion to implement the ca(u)lk first being processed, is overflowing the amplification profile of an example of portion.

Figure 18 B is after utilizing the enforcement ca(u)lk processing of plastic working portion, overflows the amplification profile of an example of portion.

Figure 19 A is utilizing plastic working portion to implement the ca(u)lk first being processed, overflows other the amplification profile of example of portion.

Figure 19 B is utilizing after plastic working portion implements ca(u)lk processing, overflows other the amplification profile of example of portion.

Figure 20 A is utilizing plastic working portion to implement the ca(u)lk first being processed, overflows other the amplification profile of example of portion.

Figure 20 B is utilizing after plastic working portion implements ca(u)lk processing, overflows other the amplification profile of example of portion.

Figure 21 a is utilizing plastic working portion to implement the ca(u)lk first being processed, overflows other the amplification profile of example of portion.

Figure 21 B is utilizing after plastic working portion implements ca(u)lk processing, overflows other the amplification profile of example of portion.

Figure 22 is the sectional drawing of hydrodynamic bearing device of other structure.

Figure 23 A represents a mode of ca(u)lk processing, utilizes plastic working portion to implement the amplification profile of the lip part of ca(u)lk first being processed.

Figure 23 B represents a mode of ca(u)lk processing, utilizes plastic working portion to implement the amplification profile of ca(u)lk processing lip part afterwards.。

Figure 24 is the sectional drawing of spindle motor that possesses the hydrodynamic bearing device of the 3rd mode of execution of the present invention.

Figure 25 is the sectional drawing of hydrodynamic bearing device.

Figure 26 is the sectional drawing of bearing sleeve.

Figure 27 is the planimetric map of bearing sleeve and lip part opposing end faces.

Figure 28 A is the figure of an example of the conception manufacture method of representing spindle unit, is the sectional drawing of the configuration relation of axial region before expression is pressed into and lip part.

Figure 28 B is the figure of an example of the conception manufacture method of representing spindle unit, is the sectional drawing that expression is pressed into the configuration relation of axial region when finishing and lip part.。

Figure 28 C is the figure of an example of the conception manufacture method of representing spindle unit, is illustrated in to be pressed into lip part to be applied the sectional drawing of the configuration relation of axial region in stage of corrective force and lip part after finishing.

Figure 29 A is the figure of an example of the conception manufacture method of representing spindle unit, is the sectional drawing of the configuration relation of axial region before expression is pressed into and lip part.

Figure 29 B is other the figure of example of the conception manufacture method of representing spindle unit, expression be pressed into midway axial region and the sectional drawing of the configuration relation of lip part.

Figure 29 C is other the figure of example of the conception manufacture method of representing spindle unit, and expression is pressed into the sectional drawing of the configuration relation of axial region when finishing and lip part.

Figure 30 A is other the figure of example of the conception manufacture method of representing spindle unit, the sectional drawing of the axial region before expression is pressed into and the configuration relation of lip part.

Figure 30 B is other the figure of example of the conception manufacture method of representing spindle unit, expression be pressed into midway axial region and the sectional drawing of the configuration relation of lip part.

Figure 31 is the sectional drawing of hydrodynamic bearing device of other structure.

Figure 32 is the sectional drawing of spindle motor that possesses the hydrodynamic bearing device of the 4th mode of execution of the present invention.

Figure 33 is the sectional drawing of hydrodynamic bearing device.

Figure 34 is the sectional drawing of bearing sleeve.

Figure 35 is the planimetric map of bearing sleeve and lip part opposing end faces.

Figure 36 is the sectional drawing of an example of the conception manufacturing process that represents spindle unit.

Figure 37 A is the lip part before the ca(u)lk processing after representing to be pressed into, and reaches the amplification profile of an example of the plastic working portion that lip part enforcement ca(u)lk is processed.

Figure 37 B is that expression utilizes plastic working portion to implement the amplification profile of an example of the lip part of the state after the ca(u)lk processing.

Figure 38 A is the lip part before the ca(u)lk processing after representing to be pressed into, and reaches the amplification profile of an example of the plastic working portion that lip part enforcement ca(u)lk is processed.

Figure 38 B is that expression utilizes plastic working portion to implement other routine amplification profiles of the lip part of the state after ca(u)lk is processed.

Figure 39 is the sectional drawing of the hydrodynamic bearing device of other structures.

Figure 40 possesses the information equipment of hydrodynamic bearing device of the 5th mode of execution of the present invention with the sectional drawing of spindle motor.

Figure 41 is the sectional drawing of hydrodynamic bearing device.

Figure 42 is the sectional drawing of bearing sleeve.

Figure 43 is the planimetric map of an end face of expression thrust parts.

Figure 44 is the sectional drawing of an example of the conception assembly process of representing axial region and lip part.

Figure 45 is the sectional drawing of an example of the conception assembly process of representing axial region and lip part.

Figure 46 is the sectional drawing of an example of the conception assembly process of representing axial region and lip part.

Figure 47 is the major component amplification profile of Figure 46.

Figure 48 A is the major component sectional drawing of the employed forming metal mould of injection forming process of covering part.

Figure 48 B is the sectional drawing of the lip part after the injection moulding covering part.

Figure 49 is the sectional drawing of first variation of expression hydrodynamic bearing device of the present invention.

Figure 50 is the sectional drawing of second variation of expression hydrodynamic bearing device of the present invention.

Figure 51 is the major component amplification profile of spindle unit of other variation.

Figure 52 is the flow chart of manufacture method of the shaft member for fluid bearing device of the 6th mode of execution of the present invention.

Figure 53 is the sectional drawing of spindle motor that possesses the hydrodynamic bearing device of the 6th mode of execution of the present invention.

Figure 54 is the sectional drawing of hydrodynamic bearing device.

Figure 55 is the sectional drawing of bearing sleeve.

Figure 56 is the planimetric map of bearing sleeve and lip part opposing end faces.

Figure 57 is that the number of degrees of the outside dimension of the axial region in 1 group of group of representing to mate mutually distribute, and the figure of an example of the number of degrees of the internal diameter size in the hole of lip part distribution.

The number of degrees of the outside dimension of the axial region in 1 group of group that Figure 58 represents to mate mutually distribute, and his figure of example that distributes of the number of degrees of the internal diameter size in the hole of lip part.

Figure 59 is the flow chart of manufacture method of shaft member for fluid bearing device of other structure.

Figure 60 is that the number of degrees of the outside dimension of the axial region in 1 group of group of representing to mate mutually distribute, and the existing illustration of the number of degrees of the internal diameter size in the hole of lip part distribution.

[explanation of symbol]

1,51,101,151,301,371,401,451,501,601 hydrodynamic bearing devices

2,102,302,402,502,602 spindle units

3,53,103,153,303,373,403,453,503,603 hubs

7,57,107,157,307,377,407,457,507,607 housings

8,108,308,408,508,608 bearing sleeves

10,110,310,410,510,610 sealed members

21,121,321,421,521,621 axial regions

21a, 121a, 321a, 421a, 621a radial bearing surface

22,122,322,422,622 lip parts

The inboard protuberance of 22d

23,123,423,525,526 ca(u)lk portions

31～35,131～135 anchor clamps

31c, 131b, 431b plasticity adds top

122d overflows portion

122d1 hypomere plane

122d2, the 122d3 conical surface

122f, the 422f recess

122g1,122g2,422g1,422g2 ridge

333,334,345,353,354 pressing components

The 422d1 big diametral plane

The 422d3 undercut groove

422e hypomere plane

522 thrust parts

523 lip parts

523c hole portion

523d, the 523e protuberance

524 covering part

525,526 ca(u)lk portions

531 ca(u)lk moulds

The A radial bearing surface

B, C thrust shaft bearing surface

M swells (protuberance)

The P melting resin

The 622c inner peripheral surface

623 ca(u)lk fixing parts

A ₀The allowed band zone of magnitude of interference

A ₁The zonule excessively of magnitude of interference

A ₂The excessive zone of magnitude of interference

M _f, M _F1, M _F2Represent internal diameter size

MS represents outside dimension

T _f, T _SMachining tolerance

P _AimThe desired value of magnitude of interference

S1, S2, S3, S4, S5, S6 seal space

R11, R12, R21, R22, R31, R32, R41, R42, R51, R52, R61, R62 radial bearing portion

T11, T12, T21, T22, T31, T32, T41, T42, T51, T52, T61, T62 thrust bearing portion

Embodiment

Below, based on Fig. 1～Figure 12 first mode of execution of the present invention is described.At this, an example of the mode of execution that this first mode of execution is first side of the present invention.And " up and down " direction in the following description just is used for easily understanding the position relation between the constituting component of each figure, thus be not the given fluid bearing means direction or usage mode etc. are set.For other mode of executions described later also is same.

Fig. 1 represents to possess the sectional drawing of spindle motor of the hydrodynamic bearing device 1 of first mode of execution of the present invention.This spindle motor for example is used for using as the HDD that possesses disk, possesses: the supporting of non-contact diametrically is equipped with the hydrodynamic bearing device 1 of the spindle unit 2 of hub 3; For example by the drive portion 4 that constitutes across the relative stator coil 4a in the gap of radial direction and rotor magnet 4b; Carriage 5.Stator coil 4a is fixed in carriage 5, and rotor magnet 4b is fixed in hub 3.The housing 7 of hydrodynamic bearing device 1 is fixed in the interior week of carriage 5.In addition, as shown in the drawing, dish 6 (among Fig. 1 being two) remain in hub 3.In the spindle motor that so constitutes, when when stator coil 4a switches on, make rotor magnet 4b rotation by the excitation power that produces between stator coil 4a and the rotor magnet 4b, and accompany therewith, remain in the dish 6 and the rotation of spindle unit 2 one of hub 3.

Fig. 2 represents hydrodynamic bearing device 1.This hydrodynamic bearing device 1 mainly possesses: the cover 9 of an end of housing 7, the bearing sleeve 8 that is fixed in the interior week of housing 7, inaccessible housing 7, the sealed member 10 that sets in the other end opening side of housing, carry out counterrotating spindle unit 2 with respect to housing 7 and bearing sleeve 8 and sealed member 10.

Housing 7 for example forms tubular by metallic material such as brass or resin material, and is the form with its axial both ends open.The outer circumferential face 8c of bearing sleeve 8 for example by bonding (comprise loosening bonding and be pressed into bonding), be pressed into, deposited (comprising ultrasonic wave coating and laser cladding) wait the method that suits to be fixed on the inner peripheral surface 7a of housing 7.In addition, be formed with than the big footpath of inner peripheral surface 7a and be used for fixing the stationary plane 7b of cover 9 described later in the lower end side of inner peripheral surface 7a.

The porous plastid that bearing sleeve 8 for example is made of sintering metal forms cylindric.In this embodiment, bearing sleeve 8 is formed cylindric by the porous plastid that with copper is the sintering metal of primary coil, and is adhesively fixed in the inner peripheral surface 7a of housing 7.In addition, bearing sleeve 8 also can be formed by the porous plastid that nonmetallic material such as resin or pottery constitute, in addition, except that porous plastids such as sintering metal, also can be by not with inner emptying aperture or have the material of structure that lubricant oil can't pass in and out the emptying aperture of degree size and form.

Be formed with in whole of the inner peripheral surface 8a of bearing sleeve 8 or a part of cylinder zone arranged a plurality of dynamic pressure grooves the zone as the radial dynamic pressure generating unit.In this embodiment, for example as shown in Figure 3, a plurality of dynamic pressure groove 8a1 that the tilt angle is different mutually, the zone that 8a2 is arranged in the herringbone shape are formed on two positions in the axial direction separatedly.And, in this embodiment,, a side's (is upside at this) dynamic pressure groove 8a1,8a2 formed the zone form on axle direction asymmetric for circuit purpose with the lubricant oil that forms bearing inside wittingly.If describe in the illustrated mode of Fig. 3, then the dynamic pressure groove 8a1 of axial centre m1 upside (sealed member 10 sides) the axial dimension X11 that forms the zone forms dynamic pressure groove 8a2 than downside to form the axial dimension X12 in zone bigger.

For example as shown in Figure 4, as the thrust dynamic pressure generating section, be formed with at whole of the lower end surface of bearing sleeve 8 8b or a part of annular section a plurality of dynamic pressure groove 8b1 are arranged in spiral-shaped zone.It is opposed with the upper-end surface 22a of lip part described later 22 with the state of finished product that this dynamic pressure groove 8b1 forms the zone, when spindle unit 2 rotations, and the thrust bearing gap (with reference to Fig. 2) of formation first T11 of thrust bearing portion described later between the 22a of upper-end surface.

Be formed with to axially extended a plurality of axial groove 8c1 at the outer circumferential face 8c of bearing sleeve 8.These axial grooves 8c1 functions as follows: main when the use of hydrodynamic bearing device 1, the situation of the mistake quantity not sufficient of generation lubricant oil is inferior in bearing interior space, is used for as soon as possible this defective mode being returned to suitable state.

The cover 9 of the lower end side obturation of housing 7 is for example formed by metallic material or resin material, and be fixed in the stationary plane 7b that is provided with in interior all lower ends of housing 7.

The dynamic pressure groove that is formed with the arrangement mode (direction of spiral is opposite) that for example is same with Fig. 4 at whole of the upper-end surface of cover 9 9a or a part of annular section forms the zone.It is opposed with the lower end surface 22b of the state of finished product and lip part 22 that this dynamic pressure groove forms zone (thrust dynamic pressure generating section), when the rotation of spindle unit 2, and lower end surface 22b between form the thrust bearing gap (with reference to Fig. 2) of second T12 of thrust bearing portion described later.

In the present embodiment, form independently by metallic material or resin material and housing 7 as the sealed member 10 of sealing mechanism, and by be pressed into, week in the upper end that arbitrary method such as bonding, deposited, welding is fixed in housing 7.

Sealing surface 10a in that being formed with in interior week of sealed member 10 is taper forms seal space S1 between the outer circumferential face of sealing face 10a and axial region described later 21.Lubricant oil is full of under the state of hydrodynamic bearing device 1 inside, and the pasta of lubricant oil is always maintained in the scope of seal space S1.

Spindle unit (shaft member for fluid bearing device) 2 is made of axial region 21, lip part 22 that the lower end of axial region 21 is fixed on the ring-type of the hole 22c that is arranged at central authorities.In this embodiment, as shown in Figure 2, in the periphery of axial region 21, separatedly radial bearing surface 21a is arranged on two positions in the axial direction, this bearing surface 21a forms regional relative with dynamic pressure groove 8a1, the 8a2 of the inner peripheral surface 8a that is arranged at bearing sleeve 8 diametrically.Between these radial bearing surface 21a, 21a, be provided with specific diameter to the little withdrawing slot part 21b of the diameter of bearing surface 21a.In addition, in the part in importing the hole 22c of lip part 22, be provided with the minor diameter part 21c that is used to accommodate as the inboard protuberance 22d of the lip part 22 of plastic deformation portion with the ca(u)lk portion 23 of lip part 22 ca(u)lks described later.In this illustrated example, be provided with the minor diameter part 21c of groove shape.

The lower end of axial region 21 is pressed into lip part 22.In addition, be formed with ca(u)lk portion 23 with lip part 22 ca(u)lks at the axial end portion (is bearing sleeve 8 sides at this) of embedding area.

Assembled after the above-mentioned structure member,, thereby obtained hydrodynamic bearing device 1 as finished product to bearing interior space packing lubrication oil.At this, can use various lubricant oil as the lubricant oil that is full of in hydrodynamic bearing device 1 inside, but when the lubricant oil that offers the Hydrodynamic bearing apparatus that disk drive device such as HDD uses considers that it uses or the temperature variation in when conveying, suitable to use low relative evaporation and the good ester of low viscosity be lubricant oil, for example dioctyl sebacate (DOS), dioctyl azelate (DOZ) etc.

In the hydrodynamic bearing device 1 of said structure, when spindle unit 2 rotation, dynamic pressure groove 8a1, the 8a2 of the both sides of bearing sleeve 8 forms the zone across the radial bearing gap and relative with radial bearing surface 21a, the 21a of axial region 21.And, follow the rotation of spindle unit 2, even form in the zone at up and down any dynamic pressure groove 8a1,8a2, lubricant oil is pressed into towards the axial centre m1 of dynamic pressure groove 8a1,8a2, its pressure rises.Utilize the dynamic pressure effect of this kind dynamic pressure groove 8a1,8a2, rotating freely diametrically, first R11 of radial bearing portion and second R12 of radial bearing portion of non-contact supporting shaft part 2 are formed on two positions respectively in the axial direction separatedly.

Meanwhile, form the thrust bearing gap between the upper-end surface 22a of zone and relative therewith lip part 22 at the dynamic pressure groove 8b1 that is provided with on the 8b of the lower end surface of bearing sleeve 8 and form thrust bearing gap between the lower end surface 22b of zone and relative therewith lip part 22 at the dynamic pressure groove that is provided with on the 9a of the upper-end surface of cover 9, utilize the dynamic pressure effect of dynamic pressure groove to form the oil film of lubricant oil respectively.And, utilize the pressure of these oil films, be formed in first T11 of thrust bearing portion and second T12 of thrust bearing portion of non-contact supporting shaft part 2 on the thrust direction respectively.

Below, an example of the manufacturing process of spindle unit 2 is described based on Fig. 5 to Fig. 8.

Fig. 5 represents to be used for the skeleton diagram of device of the assembling of spindle unit 2.This device mainly possesses: first anchor clamps 31 that keep axial region 21; Be positioned at second anchor clamps 32 of maintenance lip part 22 of the below of first anchor clamps 31; And second anchor clamps 32 between, can keep or the 3rd anchor clamps 33 of limit flange portion 22; Can with upper-end surface (end face of the opposition side of lip part 22) the 21d butt of axial region 21, and the 4th anchor clamps 34 that utilize suitable driving mechanism that axial region 21 is pressed into towards lip part 22 sides.

Between the 3rd anchor clamps 33 and the 4th anchor clamps 34, be equipped with the 5th anchor clamps 35.These anchor clamps (the 5th anchor clamps 35) and below the 3rd anchor clamps 33 between elastomer 36 is set, under the situation of bearing, should load by elastomer 36 and to transmit to the 3rd anchor clamps 33 from the downward load of the 4th anchor clamps 34.In this case, elastomer 36 is according to load and compressive strain, thereby absorbs the 5th anchor clamps 35 displacement downwards.

First anchor clamps 31 have the retaining hole 31a of the axial region 21 that can insert axial region 21 and can keep inserting.In addition, the upper-end surface 32a of second anchor clamps 32 keeps the lower end surface 22b of lip part 22, and the lower end surface 33a of the 3rd anchor clamps 33 keeps the upper-end surface 22a of lip part 22.Thereby retaining hole 31a need form its size and dimension accurately, with radial bearing surface 21a, the 21a that can suitably keep, limit axial region 21.Equally, upper-end surface 32a and lower end surface 33a also need to form accurately its shape (planeness etc.), can suitably keep, limit both ends of the surface 22a, the 22b as the lip part 22 of thrust shaft bearing surface.

In addition, in this kind spindle unit 2, the squareness between radial bearing surface 21a and the thrust shaft bearing surface (upper-end surface 22a) influences bearing performance.Therefore, in order between described bearing surface, to obtain high squareness, wish to improve between retaining hole 31a and the upper-end surface 32a and the squareness between retaining hole 31a and the lower end surface 33a by high-precision processing in advance.In order to obtain high parallelism between the upper-end surface 32a of limit flange portion 22 in the axial direction and the lower end surface 33a, need process both sides' anchor clamps 32,33 certainly accurately.

Be provided with the 31c of plastic working portion below first anchor clamps 31, the 31c of this plastic working portion follows the decline of first anchor clamps 31, is used to make lip part 22 local generation plastic deformations, and forms ca(u)lk portion 23 between the axial region 21.In this mode of execution, the 31c of plastic working portion is the shape towards the front end taper, axial region 21 and lip part 22 is being arranged under the state of each anchor clamps 31～35, with all side butts in the upper-end surface 22a of lip part 22.In addition, the stage of hole 22c before being pressed into of lip part 22, the amount of being pressed into of anticipated requirement, and form the slightly little diameter of outside dimension than the axial region 21 that should be pressed into.

State in the use under the situation of device of structure, axial region 21 carries out with the fixing following of lip part 22.

As mentioned above,, make 34 declines of the 4th anchor clamps from axial region 21 and lip part 22 is provided with (maintenances) in the state of first anchor clamps, 31 to the 5th anchor clamps 35, and with the upper-end surface 21d butt (state shown in Figure 5) of axial region 21.In this stage, the upper-end surface 21d that the upper-end surface 35a of the 5th anchor clamps 35 is positioned at than axial region 21 more leans on the below, and in addition, the upper-end surface 35a that the upper-end surface 31b of first anchor clamps 31 is positioned at than the 5th anchor clamps 35 more leans on the below.

From making the state behind the 4th anchor clamps 34 and axial region 21 butts, the 4th anchor clamps 34 are descended, the lower end of axial region 21 is pressed into the hole 22c of lip part 22.So, be pressed into beginning, and carried out stage (in other words, axial region 21 is with respect to the stage after the stable postureization of being pressed into of lip part 22) after the specific length piezometric is gone into, make the upper-end surface 35a butt (stage shown in Figure 6) of the 4th anchor clamps 34 and the 5th anchor clamps 35.And, the 4th anchor clamps 34 are descended, the 5th anchor clamps 35 are pushed downwards, thus via elastomer 36, transmit downward load to the 3rd anchor clamps 33.Thereby, between the 3rd anchor clamps 33 and second anchor clamps 32, carry out being pressed into of axial region 21 in both ends of the surface 22a, the 22b of limit flange portion 22.

So, under the state that has limited lip part 22, proceed being pressed into of axial region 21, be pressed in the stage of having finished certain degree, make the lower end surface 34a of the 4th anchor clamps 34 and the upper-end surface 31b butt of first anchor clamps 31 at this.Fig. 7 illustration with axial region 21 by the stage after till the position of generation plurality of gaps between the upper-end surface 32a of the lower end surface 21e of (being pressed into) axial region 21 and second anchor clamps 32 relative with this face in, make the situation of first anchor clamps 31 and the 4th anchor clamps 34 butts.In addition, under this state, as shown in Figure 7, the corresponding load of amount that compressive strain takes place with elastomer 36 is applied to lip part 22 from the 3rd anchor clamps 33, thus limit flange portion 22.

And, descend by further making the 4th anchor clamps 34, push first anchor clamps 31 with the 4th anchor clamps 34 butts in the axial direction, make lip part 22 plastic deformation partly by the 31c of plastic working portion that is arranged on the lower end.At this, the 31c of plastic working portion by the taper shape, make the inner circumference edge generation plastic deformation that becomes except the upper-end surface 22a of the lip part 22 in the zone of thrust shaft bearing surface in the radial direction inboard, form thus outer circumferential face (radial bearing surface 21a) than axial region 21 more enter in the inboard protuberance 22d (with reference to Fig. 8) of all sides.Thereby, between lip part 22 that is subjected to plastic working and axial region 21, be meant that at this upper axial end at embedding area forms ca(u)lk portion 23.Above-mentioned ca(u)lk processing continues to carry out under the restriction of lip part 22.

And, under the situation that axial region 21 is formed by stainless steel geometric ratio lip part 22 hard (high rigidity) materials, as shown in the figure, also can at the position of the formation inboard of axial region 21 protuberance 22d minor diameter part 21c be set in advance.In addition, expect that lip part 22 is subjected to plastic working and ca(u)lk in the situation of inboard, for example also can form by soft metals such as brass, in addition, also can not implement cure process such as quenching.

So, between axial region 21 and lip part 22, be formed with the stage of ca(u)lk portion 23, stop the decline of the 4th anchor clamps 34, take out the integral piece (spindle unit 2) of axial region 21 and lip part 22, thereby obtain spindle unit 2 as finished product from anchor clamps 31～35.In this embodiment, first anchor clamps 31 in the stage after by till the position of the upper-end surface 32a butt of the lower end surface 21e of axial region 21 and second anchor clamps 32 (making lip part 22 plastic deformations), are stopped the 4th anchor clamps 34, taking-up assembly parts (spindle unit 2).

So, axial region 21 is pressed into lip part 22, and makes lip part 22 plastic deformation partly, thus and formed ca(u)lk portion 23 between the axial region 21, therefore, can avoid as in the past because ca(u)lk causes the distortion of axial region 21 or lip part 22 integral body.Therefore, can keep the high accuracy to shape (squareness) that obtains when being pressed into, the perhaps high surface accuracy that obtains during each component processing, and can realize by using the raising that is pressed into the formed constant intensity of ca(u)lk simultaneously.

In addition, in being pressed into operation and ca(u)lk operation, under the state of end faces of both sides 22a, the 22b of limit flange portion 22, carry out ca(u)lk processing at least, can carry out ca(u)lk under with respect to the state of the posture of axial region 21 keeping lip part 22 when being pressed into thus.In addition, can under the state of the surface accuracy of keeping the end faces of both sides 22a of restriction, 22b, carry out ca(u)lk.Especially, as this mode of execution, under the situation of the structure that the load (restraint) that adopts lip part 22 increases along with the slippage of the 4th anchor clamps 34 and the 5th anchor clamps 35, come limit flange portion 22 with the fashionable higher restraint of specific pressure.Therefore, even just in case when being pressed under situations such as generation position deflection between axial region 21 and the lip part 22, also can utilize the restriction of anchor clamps 31～33 to come the offset of house of correction rheme to move.

Further, as mentioned above, utilize elastomer 36 etc., by improving the restraint that acts on lip part 22 gradually, for example interim at the beginning of being pressed into, keep the be pressed into posture of lip part 22, and some degree allows moving horizontally of lip part 22, thereby can realize certain guiding function with respect to axial region 21.Thereby, can under the state of the position relation that forms lip part 22 and axial region 21 well, be pressed into.And in this case, Fig. 5 and shown in Figure 6 is provided with guide surface by utilizing chamfering etc. a side of axial region 21 and lip part 22 or both sides' importing side end, can be pressed into more suitable posture.

In addition, in this embodiment, even when being pressed into, utilize second and third anchor clamps 32,33 limit flange portions 22, therefore can be correctly to keep the state that be pressed into posture of axial region 21 with respect to lip part 22, be pressed into axial region 21 when perhaps correcting the planeness of both ends of the surface 22a, 22b of lip part 22 and deflection precision (squareness).In addition, if be pressed into suitably keeping being pressed under the state of posture, then there is not the problem that produces the position deflection after being pressed into, so preferred.

In addition, in this embodiment, among the upper-end surface 22a of lip part 22, make than thrust shaft bearing surface zone more in the inner part plastic deformation (forming inboard protuberance 22d) takes place, the surface accuracy of thrust shaft bearing surface is worsened.In addition, make lip part 22 except the zone of working, plastic deformation take place basically, thereby can guarantee bearing area as the thrust shaft bearing surface.

In addition, as this mode of execution, form face (inner peripheral surface of retaining hole 31a and upper-end surface 32a, lower end surface 33a) in advance accurately with each bearing surface butt of anchor clamps 31～33, and set the positional accuracy of described anchor clamps 31～33 to heavens, thereby, can be highly to keep the squareness state between radial bearing surface 21a and the thrust shaft bearing surface (upper-end surface 22a), be pressed into and ca(u)lk is fixed.

In addition, in this mode of execution, constitute order, increase successively and be subjected to axial clearance between the 4th anchor clamps 34 of driving force (is the driving force that is used to move up and down at this) from driving mechanism with axial region 21, the 5th anchor clamps 35, first anchor clamps 31.According to this structure, descend by making the 4th anchor clamps 34, can realize above-mentioned load process (after being pressed into of beginning axial region 21, lip part 22 is applied axial restraint, then, lip part 22 is carried out ca(u)lk processing).Therefore, only can finish, can reduce equipment cost with single drive system (driving mechanism).In addition, can implement to be pressed into by a series of anchor clamps 31～35 of mutual interlock, rectification, all operations of ca(u)lk, so be preferred aspect productivity.

In addition,, carry out under the situation about being pressed into of axial region 21 following to correct, can carry out, on the other hand, also can adopt to have made up to be pressed into and bonding fixation method with the state of the amount of being pressed into that obtains a great deal of as this mode of execution.Will be pressed into bonding coefficient situation under, can utilize binder realize to strengthen constant intensity, therefore also can adopt gently to be pressed into etc.If the amount of being pressed into is little can finish, assembly precision height correspondingly then, thus fixing by following ca(u)lk to be pressed into, can be fixed the very good spindle unit 2 of intensity and accuracy to shape (assembly precision).

And, in the above-mentioned mode of execution, to being crimped on the upper-end surface 22a of smooth lip part 22, and described regional plastic deformation situation is illustrated in interior all sides by the 31c of plastic working portion that front end is the taper shape, do not need to be defined in this mode certainly.As long as can carry out ca(u)lk by plastic deformation in the inboard, the shape of the 31c of plastic working portion can be arbitrarily.

In addition, the plastic working face of lip part 22 might not need smooth, also can be provided with can be easily in projection of the shape of inboard plastic deformation etc.In addition, need on whole circumference, not make lip part 22 plastic deformations (forming inboard protuberance 22d).Consider the essential fastening strength or the easiness of plastic working etc., also can by forming a plurality of inboard protuberance 22d in a circumferential direction intermittently ca(u)lk portion 23 be set in the interior week of upper-end surface 22a.

In addition, in this mode of execution, illustration ca(u)lk portion 23 is arranged at the situation of axial region 21 and the upper axial end (upper-end surface 22a side) of the embedding area of lip part 22, but also can adopt in advance another distolateral formation minor diameter part, and realize fastening fixing structure by itself and ca(u)lk portion 23 (inboard protuberance 22d) at lip part 22.For example as shown in Figure 9, also can be from the lower end surface 22b side of lip part 22 towards the outstanding minor diameter part 22e that forms of interior week, and at the position of the lower end surface 21e butt of itself and axial region 21, ca(u)lk lip part 22.Certainly, utilize the improvement of each anchor clamps or driving mechanism, also can form ca(u)lk portion 23 at axial two ends.

In addition, in this embodiment, illustration can be with the lip part 22 that produces by ca(u)lk processing to the plastic deformation of radial direction inboard to the position that axial region 21 sides are overflowed, the situation of the minor diameter part 21c of groove shape is set, but also can adopts structure in addition.For example as the illustration of Figure 10, the axial region 21 that is provided with step 21f (being taper at this) in the outer circumferential face of axial region 21, between radial bearing surface 21a and the embedding area is pressed into lip part 22.And, with above-mentioned same, by the 31c of plastic working portion the upper-end surface 22a side of lip part 22 is implemented plastic working, thereby as shown in figure 11, the plastic deformation that lip part 22 can be produced is to more overflowing in the zone of path side than the step 21f that is arranged at axial region 21.In this case, as mentioned above, preferably the lower axial end at lip part 22 is provided with minor diameter part 22e, perhaps forms ca(u)lk portion 23 at axial two ends.

And under the situation that is provided with step 21f as mentioned above, the structure that simultaneously the regional 22f that is subjected to plastic working of lip part 22 is formed the zone (referring to upper-end surface 22a at this) low slightly (width is thin) than other also is effective.Implement plastic working by lip part 22, for example as shown in figure 11, can suppress more outstanding than upper-end surface 22a (opposition side of lower end surface 22b) as the protuberance 22g of plastic deformation axial thrust bearing face side generation to this structure.Thereby, can guarantee the retention force that ca(u)lk portion 23 forms, and avoid swelling 22g as far as possible the thrust shaft bearing surface is caused interference, thereby guarantee the thrust bearing performance.

In addition, also can be with the plastic working of the lip part 22 that undertaken by the 31c of plastic working portion begin as being pressed into of axial region 21 when finishing.If be pressed into the ca(u)lk operation that the moment that finishes fully begins lip part 22, then also can further improve the retention force that produces by ca(u)lk portion 23.In this case,, the 4th anchor clamps 34 are cut apart in order to be pressed into axial region 21 and the 31c of plastic working portion independently downwards, and for drive independently (moving up and down) they, need the driving mechanism of a plurality of systems.

In addition, in this embodiment, the restriction of the lip part 22 that will form by second anchor clamps 32 and the 3rd anchor clamps 33 be located at when beginning axial region 21 be pressed into beginning after, but also can be the time with the restriction beginning be pressed into be made as when beginning consistent.Perhaps if be purpose to correct by being pressed into the position deflection that causes, also can than before being pressed into when finishing slightly or be pressed into finish after, the stage begins restriction (rectification) arbitrarily in the ca(u)lk operation.

In addition, in this embodiment, lip part 22 is implemented plastic working partly, thus and axial region 21 between form ca(u)lk portion 23 situation be illustrated, but be not limited thereto.For example, also can implement plastic working partly, thereby and form ca(u)lk portion 23 between the lip part 22 axial region 21 as long as the surface accuracy (roundness or coaxality) of radial bearing surface 21a, 21a can be kept highi degree of accuracy.In addition, at this moment, in order to realize the plastic deformation (for example stretching out) of the part of axial region 21 with minimum load to the radial direction outside, for example omit diagram, also axial protuberance can be set in the lower end side of axial region 21, after being pressed into when finishing or finishing, lateral buckling outside radial direction and form ca(u)lk portion.

In addition, in this embodiment, in order to form the amount of being pressed into of regulation, to axial region 21 being pressed into the hole 22c of lip part 22, and the situation of position that makes the 31c of plastic working portion drop to the upper-end surface 32a butt of the lower end surface 21e of axial region 21 and second anchor clamps 32 is illustrated, but described being pressed into and a ca(u)lk mode example only.For example, the skew that also can remedy axial region 21 and lip part 22, tolerance of size (mean value or its permission amplitude) that each course of working produced is a purpose, and the power that is pressed into when axial region is pressed into lip part is set ca(u)lk power.

If with structure shown in Figure 5 is that example describes, at first, for example wait and detect axial region 21 beginning, be subjected to reaction force from lip part 22 as axial region 21 to the power that is pressed in the stage that is pressed into of lip part 22 (Fig. 6) by the load sensor that is arranged at the 4th anchor clamps 34.And, based on the detected power of being pressed into, infer the magnitude of interference (amount of being pressed into) of axial region 21 and lip part 22.If can infer magnitude of interference, (by the being pressed into generation) fastening force that then can predict this moment and obtain, therefore in the constant mode of summation of retention force that is pressed into generation by this and the retention force that is produced by ca(u)lk, presumptive magnitude of interference is set the maximum value of the needed load of ca(u)lk.And, add man-hour (Fig. 7 and Fig. 8) at ca(u)lk, wait by the load sensor that is provided with at the 4th anchor clamps 34 and to detect first anchor clamps 31 and be subjected to from lip part 22 reaction forces with the 31c of plastic working portion, and continue to carry out ca(u)lk processing, in stage after the maximum value of the ca(u)lk load that the checkout value arrival of ca(u)lk load is set in advance, stop the 4th anchor clamps 34 and first anchor clamps 31.

So, maximum value by control ca(u)lk power (ca(u)lk load), by the assembling of the axial region that is pressed into mutually 21 with lip part 22, even there is uneven situation in its amount of being pressed into, the axial region 21 that also spindle unit 2 as finished product can be had remains constant with the retention force of lip part 22.Thereby, improve yield rate, high-quality spindle unit 2 can stably be provided.

And, in the above description, to being that the situation that constant mode is set ca(u)lk power (perhaps ca(u)lk amount) is illustrated, but also can set ca(u)lk power based on other benchmark from the retention force that is pressed into from the summation of the retention force of ca(u)lk.For example, also can pre-determine threshold value to being pressed into power, under the value of the detected power of being pressed into becomes situation more than the above-mentioned threshold value, apply certain ca(u)lk power, value in the detected power of being pressed into is lower than under the situation of threshold value, sets according to the mode of setting the increasing amount of the ca(u)lk power that should apply with the difference of threshold value.Perhaps, also can be only under being lower than the situation of above-mentioned threshold value, the value of the detected power of being pressed into applies certain ca(u)lk power, and to set ca(u)lk power from the retention force that is pressed into from the mode that the summation of the retention force of ca(u)lk always satisfies threshold value.

In addition,, also can detect the described reaction force that should detect separately, also can be used as its aggregate values and detect except that with being pressed into power and ca(u)lk power by detecting its reaction force at the load sensor that is provided with on the 4th anchor clamps 34.Certainly, if the independent driving mechanism of use carries out being pressed into of axial region 21 and processes to the ca(u)lk of lip part 22, also detection unit can be set individually.Load sensor perhaps, also can be directly be set on first anchor clamps 31 that carry out ca(u)lk processing to be waited and detects reaction force.In addition, if the maximum value of ca(u)lk load can be scaled the slippage (to lip part 22 amounts of being pressed into) of the plastic working 31c of portion, also can control the ca(u)lk amount by the positioning control of first anchor clamps 31 with the 31c of plastic working portion.

In addition, the present invention is not limited to the illustrated structure of Fig. 2, also applicable to the hydrodynamic bearing device that is other structures.

For example in the illustrative mode of execution of Fig. 2, outer circumferential face with axial region 21 has been described as radial bearing surface 21a, the situation that the upper-end surface 22a and the lower end surface 22b of lip part 22 used as the thrust shaft bearing surface respectively, but be not limited thereto.For example, also the present invention can be applicable to the spindle unit of only the upper-end surface 22a among end faces of both sides 22a, the 22b being used as the hydrodynamic bearing device of the structure of thrust shaft bearing surface use.

Figure 12 represents to have only with the sectional drawing of upper-end surface 22a as the hydrodynamic bearing device 51 of the structure of thrust shaft bearing surface use.The characteristic point of this hydrodynamic bearing device 51 (with the main difference point of the described hydrodynamic bearing device 1 of Fig. 2) is as follows.Promptly, in hydrodynamic bearing device 51, the hub 53 that is fixed in the upper end (opposition side of lip part 22) of axial region 21 mainly has: be positioned at the round plate 53a of opening side (upside) of housing 57 and the cylindrical portion 53b that extends to axial below from the peripheral part of round plate 53a.In addition, the dynamic pressure groove that is provided with the arrangement mode that for example is shown in Figure 4 at the upper-end surface of housing 57 57c forms zone (spiral towards opposite), and the lower end surface 53a1 of the 53a of opposite circular portion between form the thrust bearing gap of second T12 of thrust bearing portion.

The periphery of housing 57 be formed with towards above the sealing surface 57d of the taper that enlarges gradually of diameter.Between the inner peripheral surface 53b1 of the sealing surface 57d of this taper and cylindrical portion 53b, form the seal space S1 of ring-type, the seal space S1 of this ring-type from the inaccessible side (below) of housing 57 to opening side (top) reduced radius direction size gradually.And among Figure 12, the inner peripheral surface 57a of housing 57 and stationary plane 57b correspond respectively to the inner peripheral surface 7a and the stationary plane 7b of the housing 7 among Fig. 2.Structure in addition is identical with the described structure of Fig. 2, so omit explanation.

So, even only under the situation of upper-end surface 22a with lip part 22 as the use of thrust shaft bearing surface, be pressed into and ca(u)lk by using simultaneously, and make lip part 22 plastic deformation and form ca(u)lk portion 23 partly, even after ca(u)lk processing, also can keep the surface accuracy of radial bearing surface 21a and thrust shaft bearing surface etc. and the squareness between described bearing surface to heavens.In addition, can access spindle unit 2 simultaneously with high constant intensity.

In addition, as mentioned above, by using in advance the spindle unit that will form accurately to carry out above-mentioned be pressed into and ca(u)lk is fixed, can access the spindle unit 2 that between radial bearing surface 21a and thrust shaft bearing surface (upper-end surface 22a), has high squareness with the face (inner peripheral surface of retaining hole 31a and upper-end surface 32a, lower end surface 33a) of each bearing surface butt of anchor clamps 31～33.

And, in the above description, all housing 7,57 and bearing sleeve 8 are provided with independently, but the parts more than 2 integrated each other (form by same material, perhaps embed a side parts and contour forming the opposing party's parts) that also can be in the scope that can assemble will from the parts group of the fixed side that constitutes described hydrodynamic bearing device 1,51, select.For example in structure shown in Figure 2, can be integrated between housing 7 and bearing sleeve 8, housing 7 and cover 9, housing 7 and the sealed member 10.Also can with housing 7 and bearing sleeve 8, and sealed member 10 integrated.In addition, in the structure shown in Figure 12, housing 57 and bearing sleeve 8 perhaps can be integrated between housing 57 and the cover 9.

Below, based on Figure 13～Figure 22 second mode of execution of the present invention is described.At this, this second mode of execution relates to an example of the mode of execution of first side of the present invention.

Figure 13 represents to possess the sectional drawing of spindle motor of the hydrodynamic bearing device 101 of second mode of execution of the present invention.This spindle motor for example uses as the disk drive motor that possesses the HDD of disk, possesses: the supporting of non-contact diametrically is equipped with the hydrodynamic bearing device 101 of the spindle unit 102 of hub 103; For example by the drive portion 104 that constitutes across the relative stator coil 104a in the gap of radial direction and rotor magnet 104b; Carriage 105.Stator coil 104a is fixed in carriage 105, and rotor magnet 104b is fixed in hub 103.The housing 7 of hydrodynamic bearing device 101 is fixed in the interior week of carriage 105.In addition, as shown in the drawing, dish 106 (among Figure 13 being two) remain in hub 103.In the spindle motor that so constitutes, when when stator coil 104a switches on, make rotor magnet 104b rotation by the excitation power that produces between stator coil 104a and the rotor magnet 104b, and accompany therewith, remain in the dish 106 and the rotation of spindle unit 102 one of hub 103.

Figure 14 represents hydrodynamic bearing device 101.This hydrodynamic bearing device 101 mainly possesses: the cover 109 of an end of housing 107, the bearing sleeve 108 that is fixed in the interior week of housing 107, inaccessible housing 107, the sealed member 110 that sets in the other end opening side of housing, carry out counterrotating spindle unit 102 with respect to housing 107 and bearing sleeve 108 and sealed member 110.

Housing 107 for example forms tubular by metallic material such as brass or resin material, and is the form with its axial both ends open.The outer circumferential face 108c of bearing sleeve 108 for example by bonding (comprise loosening bonding and be pressed into bonding), be pressed into, deposited (comprising ultrasonic wave coating and laser cladding) wait the method that suits to be fixed on the inner peripheral surface 107a of housing 107.In addition, be formed with than the big footpath of inner peripheral surface 107a and be used for fixing the stationary plane 107b of cover 109 described later in the lower end side of inner peripheral surface 107a.

The porous plastid that bearing sleeve 108 for example is made of sintering metal forms cylindric.In this embodiment, bearing sleeve 108 is formed cylindric by the porous plastid that with copper is the sintering metal of primary coil, and is adhesively fixed in the inner peripheral surface 107a of housing 107.In addition, bearing sleeve 108 also can be formed by the porous plastid that nonmetallic material such as resin or pottery constitute, in addition, except that porous plastids such as sintering metal, also can be by not with inner emptying aperture or have the material of structure that lubricant oil can't pass in and out the emptying aperture of degree size and form.

Be formed with in whole of the inner peripheral surface 108a of bearing sleeve 108 or a part of zone arranged a plurality of dynamic pressure grooves the zone as the radial dynamic pressure generating unit.In this embodiment, for example as shown in figure 15, a plurality of dynamic pressure groove 108a1 that the tilt angle is different mutually, the zone that 108a2 is arranged in the herringbone shape are formed on two positions in the axial direction separatedly.And, in this embodiment,, dynamic pressure groove 108a1, the 108a2 of a side (is upside at this) formed the zone form on axle direction asymmetric for circuit purpose with the lubricant oil that forms bearing inside wittingly.If describe in the illustrated mode of Figure 15, then the axial dimension X21 of the dynamic pressure groove 108a1 arrange regional of axial centre m2 upside (sealed member 110 sides) forms bigger than the axial dimension X22 of the dynamic pressure groove 108a2 arrange regional of downside.

For example as shown in figure 16, as the thrust dynamic pressure generating section, be formed with in whole of the lower end surface of bearing sleeve 108 108b or a part of zone a plurality of dynamic pressure groove 108b1 are arranged in spiral-shaped zone.This dynamic pressure groove 108b1 arrange regional is opposed with the upper-end surface 122a of the state of finished product and lip part described later 122, when spindle unit 102 rotations, and forms the thrust bearing gap (with reference to Figure 14) of first T21 of thrust bearing portion described later between the 122a of upper-end surface.

Be formed with to axially extended a plurality of axial groove 108c1 at the outer circumferential face 108c of bearing sleeve 108.These axial grooves 108c1 functions as follows: main when the use of hydrodynamic bearing device 101, the situation of the mistake quantity not sufficient of generation lubricant oil is inferior in bearing interior space, is used for as soon as possible this defective mode being returned to suitable state.

The cover 109 of the lower end side obturation of housing 107 is for example formed by metallic material or resin material, and be fixed in the stationary plane 107b that is provided with in interior all lower ends of housing 107.At this moment, the fixation method of cover 109 can with bearing sleeve 108 similarly use bonding, be pressed into, welding, arbitrary method such as deposited.

Be formed with the dynamic pressure groove arrange regional of the arrangement mode (direction of spiral is opposite) that for example is same with Figure 16 in whole of the upper-end surface of cover 109 109a or a part of zone.This dynamic pressure groove arrange regional (thrust dynamic pressure generating section) is opposed with the lower end surface 122b of the state of finished product and lip part 122, when the rotation of spindle unit 102, and lower end surface 122b between form the thrust bearing gap (with reference to Figure 14) of second T22 of thrust bearing portion described later.

In the present embodiment, form independently by metallic material or resin material and housing 107 as the sealed member 110 of sealing mechanism, and by be pressed into, week in the upper end that arbitrary method such as bonding, deposited, welding is fixed in housing 107.

Sealing surface 110a in that being formed with in interior week of sealed member 110 is taper forms seal space S2 between the outer circumferential face of sealing face 110a and axial region described later 121.Lubricant oil is full of under the state of hydrodynamic bearing device 101 inside, and the pasta of lubricant oil is always maintained in the scope of seal space S2.

Spindle unit 102 is made of axial region 121, lip part 122 that the lower end of axial region 121 is fixed on the ring-type of the hole 22c that is arranged at central authorities.As shown in figure 14, be formed with radial bearing surface 121a in the periphery of axial region 121, this radial bearing surface 121a dynamic pressure groove 108a1,108a2 arrange regional with the inner peripheral surface 108a that is arranged at bearing sleeve 108 diametrically is relative.In this embodiment, radial bearing surface 121a is arranged on two positions in the axial direction separatedly.Between described radial bearing surface 121a, 121a, be provided with the diameter specific diameter to the little withdrawing slot part 121b of bearing surface 121a.

The lower end of axial region 121 is pressed into lip part 122.In addition, be formed with ca(u)lk portion 123 with lip part 122 ca(u)lks at the axial end portion (is bearing sleeve 108 sides at this) of the embedding area of axial region 121.

And, preferably form for axial region 121 by excellent material such as stainless steel equal strength, rigidity, antifriction consumptions, compare the plastic working excellent material formation that ca(u)lk adds man-hour with axial region 121 for lip part 122 preferences such as brass etc.

Assembled after the above-mentioned structure member,, thereby obtained hydrodynamic bearing device 101 as finished product to bearing interior space packing lubrication oil.At this, can use various lubricant oil as the lubricant oil that is full of in hydrodynamic bearing device 101 inside, but when the lubricant oil that offers the Hydrodynamic bearing apparatus that disk drive device such as HDD uses considers that it uses or the temperature variation in when conveying, suitable to use low relative evaporation and the good ester of low viscosity be lubricant oil, for example dioctyl sebacate (DOS), dioctyl azelate (DOZ) etc.

In the hydrodynamic bearing device 101 of said structure, when spindle unit 102 rotation, the dynamic pressure groove 108a1 of the both sides of bearing sleeve 108,108a2 arrange regional are across the radial bearing gap and relative with radial bearing surface 121a, the 121a of axial region 121.And, follow the rotation of spindle unit 102, even in up and down any dynamic pressure groove 108a1,108a2 arrange regional, lubricant oil is pressed into towards the axial centre m2 of dynamic pressure groove 108a1,108a2, its pressure rises.Utilize the dynamic pressure effect of this kind dynamic pressure groove 108a1,108a2, rotating freely diametrically, first R21 of radial bearing portion and second R22 of radial bearing portion of non-contact supporting shaft part 102 are formed on two positions respectively in the axial direction separatedly.

Meanwhile, in the thrust bearing gap between the upper-end surface 122a of dynamic pressure groove 108b1 arrange regional that is provided with on the 108b of the lower end surface of bearing sleeve 108 and relative therewith lip part 122 and the thrust bearing gap between the lower end surface 122b of dynamic pressure groove arrange regional that is provided with on the 109a of the upper-end surface of cover 109 and relative therewith lip part 122, utilize the dynamic pressure effect of dynamic pressure groove to form the oil film of lubricant oil respectively.And, utilize the pressure of these oil films, be formed in first T21 of thrust bearing portion and second T22 of thrust bearing portion of non-contact supporting shaft part 102 on the thrust direction respectively.

Below, an example of the manufacturing process of spindle unit 102 is described based on Figure 17 and Figure 18 A, 18B.

Figure 17 represents to be used for the skeleton diagram of device of the assembling of spindle unit 102.This device mainly possesses: first anchor clamps 131 that keep axial region 121; Be positioned at second anchor clamps 132 of maintenance lip part 122 of the below of first anchor clamps 131; And second anchor clamps 132 between, can keep or the 3rd anchor clamps 133 of limit flange portion 122.

In addition, in this mode of execution, above axial region 121, be equipped with the 4th anchor clamps 134 that utilize suitable driving mechanism that axial region 121 is pressed into towards lip part 122 sides, and between the 3rd anchor clamps 133 and the 4th anchor clamps 134, be equipped with the 5th anchor clamps 135.At this, the 5th anchor clamps 135 and below the 3rd anchor clamps 133 between elastomer 136 is set, under the situation of bearing, should load by elastomer 136 and to transmit to the 3rd anchor clamps 133 from the downward load of the 4th anchor clamps 134.In this case, elastomer 136 is according to load and compressive strain, thereby absorbs the 5th anchor clamps 135 displacement downwards.

First anchor clamps 131 have the hole 131a that can insert and keep axial region 121.In addition, the upper-end surface 132a of second anchor clamps 132 keeps and limit flange portion 122 with the lower end surface 133a of the 3rd anchor clamps 133 that are positioned at its top.Thereby hole 131a need form its size and dimension accurately, can there not be radial bearing surface 121a, the 121a that keeps and limit with rocking axial region 121.Equally, upper-end surface 132a and lower end surface 133a also need to form accurately its shape (planeness etc.), can seamlessly keep and limit both ends of the surface 122a, the 122b of the lip part 122 that comprises the thrust shaft bearing surface.

In addition, in this kind spindle unit 102, the squareness between radial bearing surface 121a and the thrust shaft bearing surface (upper-end surface 122a) influences bearing performance.Therefore, in order between described bearing surface, to obtain high squareness, wish to improve between hole 131a and the upper-end surface 132a and the squareness between hole 131a and the lower end surface 133a by high-precision processing in advance.In order to obtain high parallelism between the upper-end surface 132a of limit flange portion 122 in the axial direction and the lower end surface 133a, need process both sides' anchor clamps 132,133 certainly accurately.

Be provided with the 131b of plastic working portion below first anchor clamps 131, the 131b of this plastic working portion follows the decline of first anchor clamps 131, be used for interior week of lip part 122 is implemented ca(u)lk processing, and and axial region 121 between form ca(u)lk portion 123.In this mode of execution, shown in Figure 18 A, the 131b of plastic working portion is along with the shape that reduces its radial direction width dimensions towards lower end side (along with near lip part 122 sides), and is made of first conical surface 131b1 that is positioned at its outer circumferential side and second conical surface 131b2 that is positioned at all sides.

At this, if be conceived to shape with the opposed lip part 122 of the 131b of plastic working portion, then week in the 122a of the upper-end surface of described lip part 122,, supposition overflows the 122d of portion except having the part of the lip part 122 under the situation of smooth upper-end surface 122a to be formed with at whole mask.If refer to the lip part 122 shown in Figure 18 A, then constitute and overflow the 122d of portion by the hypomere plane 122d1 that moves back established amount from the plan-position identical to 122b rear flank, lower end surface via step with upper-end surface 122a.Thereby, axial region 121 and lip part 122 are being arranged under the state of each anchor clamps 131～135, the 131b of plastic working portion is positioned at the top of the 122d of the portion of overflowing of lip part 122, perhaps overflows the hypomere plane 122d1 butt of the 122d of portion with formation.

In addition, the inner peripheral surface 122c at the lip part 122 that forms the hole that should be pressed into axial region 121 is formed with the undercut groove 122e as large-diameter portion.At this, undercut groove 122e be arranged on the 122d of the portion of overflowing that bears ca(u)lk processing near, by bearing its otch volume of ca(u)lk processing the minimizing.In addition, the amount of being pressed into of the stage forecast before being pressed into regulation and will form littler except the internal diameter of the inner peripheral surface 122c of undercut groove 122e than the external diameter of the underpart of the axial region 121 that should be pressed into.

Below, the example of assembling procedure of spindle unit 102 of the situation of the device that uses said structure is described.In this embodiment, the order with axial region 121, the 5th anchor clamps 135, first anchor clamps 131 is applied downward load, under the restriction of lip part 122, carry out essence be pressed into and the situation of ca(u)lk processing describes.

At first,, the 4th anchor clamps 134 are descended, the lower end of axial region 121 is pressed into the hole of lip part 122 from state as shown in figure 17.And, in be pressed into stage stable postureization after of axial region 121, begin to utilize the 4th anchor clamps 134 that the 5th anchor clamps 135 are pressed into downwards, thereby, transmit downward load to the 3rd anchor clamps 133 by elastomer 136 with respect to lip part 122.Thereby, in the time of by both ends of the surface 122a, the 122b of limit flange portion 122 between the 3rd anchor clamps 133 and second anchor clamps 132, carry out being pressed into of axial region 121.

So, under the state that has limited lip part 122, proceed being pressed into of axial region 121, be pressed into the stage of having finished certain degree at this, make the 4th anchor clamps 134 and first anchor clamps, 131 butts, first anchor clamps 131 are pressed into to the 122d of the portion of overflowing that is arranged at lip part 122.So, implement plastic working (ca(u)lk processing) to overflowing the 122d of portion, shown in Figure 18 B, and form ca(u)lk portion 123 between the axial region 121 by the 131b of plastic working portion by the lower end that is arranged at first anchor clamps 131.Above-mentioned ca(u)lk processing continues to carry out under the restriction of lip part 122.

At this moment, the part that the ca(u)lk that is subjected to being undertaken by the 131b of plastic working portion in overflowing the 122d of portion is processed forms the similar recess 122f of shape with the 131b of plastic working portion.And, process ridge (first ridge) 122g1 that produces by ca(u)lk in the outer circumferential side formation of recess 122f.At this, because from the inside all lateral deviations of the external diameter end that overflows the 122d of portion from the position implement ca(u)lk processing, therefore the first ridge 122g1 is created in the outer radius portion of overflowing the 122d of portion, correctly says, is created in the outer radius portion that constitutes the hypomere plane 122d1 that overflows the 122d of portion.In addition, the interior all sides that are subjected to the recess 122f that ca(u)lk processing produces in overflowing the 122d of portion form the second ridge 122g2.

So, be pressed into lip part 122 at axial region 121, and form the stage after the ca(u)lk portion 123 between axial region 121 and the lip part 122, stop the decline of the 4th anchor clamps 134, from anchor clamps 131～135, take out the one builtup member of axial region 121 and lip part 122, obtain spindle unit 102 as finished product.In this embodiment, the stage of (after making lip part 122 plastic deformations) till the position of the upper-end surface 132a butt of the lower end surface 121c that first anchor clamps 131 is pushed into axial region 121 and second anchor clamps 132, stop the 4th anchor clamps 134, take out builtup member (spindle unit 102).

So, axial region 121 is pressed into lip part 122, and make lip part 122 plastic deformation partly, form ca(u)lk portion 123 thus and between the axial region 121, thereby, can between axial region 121 and lip part 122, apply by fastening force that is pressed into generation and the fastening force that produces by ca(u)lk, and can realize the raising of constant intensity.In addition, the distortion of lip part 122 (plastic deformation) is local get final product, therefore, can keep the high accuracy to shape (squareness) that obtains when being pressed into, perhaps the state raising of realization constant intensity down of the high surface accuracy that obtains during each component processing.

In addition, simultaneously, in the 122a of the upper-end surface of lip part 122, set in advance in week and overflow the 122d of portion, and this is overflowed the 122d of portion carry out ca(u)lk processing, therefore the plastic flow that is produced by ca(u)lk processing be formed on recess 122f around the 122d of the portion of overflowing absorb.Therefore, can reduce the amount of the plastic deformation (plastic flow) that produces to the outer circumferential side of recess 122f, and the height of the first ridge 122g1 can be suppressed for lower.Especially, as this mode of execution, under the first ridge 122g1 is formed on situation on the 122d1 of hypomere plane, the first ridge 122g1 can be suppressed the step amount of hypomere plane 122d1 and upper-end surface 122a towards bearing sleeve 108 side-prominent amounts than thrust bearing.Thus, relax or eliminate the interference of the first ridge 122g1, thereby can bring into play good bearing performance the thrust shaft bearing surface.Specifically,, more preferably be made as below the 2 μ m, can avoid interference, thereby guarantee good bearing performance the essence of bearing performance by the first ridge 122g1 is located at below the 3 μ m from the projecting height of thrust shaft bearing surface.

In addition, as this mode of execution, the interior circumferential portion of upper-end surface 122a is close more to be leaned on lower end surface 122b side and forms the situation of overflowing the 122d of portion than the same level with the thrust shaft bearing surface so long as make, by the amount of retreating that constitutes the hypomere plane 122d1 that overflows the 122d of portion, control the overhang of the first ridge 122g1 easily.

In addition, in this embodiment, be provided as the undercut groove 122e of large-diameter portion at the inner peripheral surface 122c of lip part 122.Therefore, by utilizing the ca(u)lk processing that arbitrary end face (being upper-end surface 122a herein) is carried out, can avoid encouraging the distortion such as warpage that all produce at lip part 122 by being pressed into, and can keep the shape of lip part 122 accurately.

And, in this embodiment, be illustrated as the situation of minor diameter part be formed with undercut groove 122e at inner peripheral surface 122c, also can adopt mode in addition certainly.That is,, also can adopt shape arbitrarily as long as can absorb the plastic deformation that the ca(u)lk processing of overflowing the 122d of portion is produced by the space that between axial region 121 and minor diameter part, forms by being pressed into.For example shown in Figure 19 A,, also the big diametral plane 122h bigger than inner peripheral surface 122c diameter can be formed on the upper end of inner peripheral surface 122c as minor diameter part.In this case, shown in Figure 19 B, utilize ca(u)lk processing to produce the second ridge 122g2, and produce plastic deformations, thus and form ca(u)lk portion 123 between the axial region 121 towards axial region 121 in interior all sides of overflowing the 122d of portion.

In addition, in this embodiment, form face (inner peripheral surface of hole 131a and upper-end surface 132a, lower end surface 133a) in advance accurately with each bearing surface butt of anchor clamps 131～133, and by setting the positional accuracy of described anchor clamps 131～133 to heavens, can be highly guaranteeing radial bearing surface 121a, to be arranged at the state of the squareness between the thrust shaft bearing surface of upper-end surface 122a, be pressed into and ca(u)lk is fixed.

In addition, in this embodiment, in being pressed into operation and ca(u)lk operation, the state with the both sides' of limit flange portion 122 end face 122a, 122b carries out ca(u)lk processing at least, therefore can carry out ca(u)lk with the posture of the axial region 121 of keeping lip part 122 when being pressed into.In addition, can carry out ca(u)lk with the state of the surface accuracy of the both sides' that keep restriction end face 122a, 122b.Especially, as this mode of execution,, follow the slippage of the 4th anchor clamps 134 and the 5th anchor clamps 135 in employing and under the situation of the structure that increases, come limit flange portion 122 by the fashionable high restraint of specific pressure to the load (restraint) of lip part 122.Therefore, even, utilize the restriction of anchor clamps 131～133 to come the offset of house of correction rheme to move just in case when being pressed into, produced between axial region 121 and the lip part 122 under the situation of position deflection etc.

In addition, in this embodiment, even when being pressed into, utilize second and third anchor clamps 132,133 to come limit flange portion 122, so, be pressed into axial region 121 when perhaps correcting the planeness of both ends of the surface 122a, 122b of lip part 122 and deflection precision (squareness) suitably to keep the state that is pressed into posture of axial region 121 with respect to lip part 122.In addition, if be pressed into suitably keeping being pressed under the state of posture, then there is not the problem that produces the position deflection after being pressed into, so preferred.

In addition,, carry out under the situation about being pressed into of axial region 121, can under the state of the amount of being pressed into that obtains a great deal of, carry out, on the other hand, also can adopt to have made up to be pressed into and bonding fixation method following rectification as this mode of execution.Will be pressed into bonding coefficient situation under, can utilize binder realize to strengthen constant intensity, gently be pressed into etc. so can adopt.If the amount of being pressed into is little can be finished, then correspondingly form good assembly precision easily, thus fixing by following ca(u)lk to be pressed into, can be fixed the very good spindle unit 102 of intensity and accuracy to shape (assembly precision).

And, among Figure 18 A, formed the situation of hypomere plane 122d1 via upper-end surface 122a and step about having overflowed the 122d of portion illustration, also can adopt shape in addition certainly.Figure 20 A represents the one example, the 122d of the portion of overflowing that this figure relates to by first conical surface 122d2 be connected with first conical surface 122d2 at its outside diameter and second conical surface 122d3 little with respect to the tilt angle of thrust shaft bearing surface constitutes than first conical surface 122d2.At this, first conical surface 122d2 footpath side within it links to each other with the big diametral plane 122h that is minor diameter part, and in addition, second conical surface 122d3 links to each other with upper-end surface 122a at its outside diameter.

In addition, in this illustrated example,, use the conical surface (first conical surface 131b1) reduced outer circumferential side to carry out ca(u)lk processing from the plastic working portion of the tiltangle 1 (for example forming below 45 °) of horizontal plane as the 131b of plastic working portion.Come to carry out ca(u)lk processing to overflowing the 122d of portion by the 131b of plastic working portion that uses this structure, the part that is subjected to ca(u)lk processing produces to the plastic deformation of outer circumferential side first conical surface 131b1 along the 131b of plastic working portion.Therefore, the first ridge 122g1 that is formed by described plastic deformation becomes mild shape.In addition, second conical surface 122d3 of described plastic deformation smaller at the tilt angle (gently) goes up as the first ridge 122g1 and generates, and the inclination on surface that therefore can make the first ridge 122g1 is near substantially horizontal.By above effect, the surface of the first ridge 122g1 is used as the part of the thrust shaft bearing surface of the upper-end surface 122a that is formed on lip part 122.Certainly, at this moment, need suitably set the tiltangle 1 and the tilt angle or the ca(u)lk amount (amount of being pressed into of the 131b of plastic working portion) of overflowing second conical surface 122d3 and the horizontal plane of the 122d of portion of first conical surface 131b1 of the 131b of plastic working portion.

In addition, for example shown in Figure 21 a,, also can use the conical surface (second conical surface 131b2) that increased interior all sides and the plastic working portion of the tiltangle 2 of horizontal plane to carry out ca(u)lk processing about the 131b of plastic working portion.In this case, the plastic deformation that is subjected to the inside all sides of part of ca(u)lk processing generates along second conical surface 131b2 of the 131b of plastic working portion.Therefore, the second ridge 122g2 that utilizes described plastic deformation to form becomes sharp-pointed upward outstanding shape.Thereby, the second ridge 122g2 is close to axial region 121 forms, so also can between the second ridge 122g2 and axial region 121, form ca(u)lk portion 123.Under this situation, the second ridge 122g2 gives prominence to big more (high more), with the fastening area increase of axial region 121, so can improve the retention force that is formed by this ca(u)lk.

Certainly, the 131b of plastic working portion is not limited to above-mentioned example, also can adopt mode arbitrarily.

In addition, in this embodiment, illustration ca(u)lk portion 123 is arranged on the situation of axial region 121 and the upper axial end (upper-end surface 122a side) of the embedding area of lip part 122, also can implement ca(u)lk processing at the suitable anchor clamps of the interior Zhou Liyong of the lower end surface of lip part 122 122b.In this case, form ca(u)lk portion 123, therefore can determine necessary anticreep power (retention force) or determine having or not of ca(u)lk that another is distolateral according to its purposes at the axial two ends of lip part 122.Perhaps, according to the inequality that is pressed into power, can replace the distolateral ca(u)lk power of adjusting and determine having or not of another distolateral ca(u)lk.

In addition, in this embodiment, stage till producing the plurality of gaps position between the upper-end surface 132a of lower end surface 121c that axial region 121 is pushed into (being pressed into) axial region 121 and second anchor clamps 132 relative with this face has been described, make the situation of first anchor clamps 131 and the 4th anchor clamps 134 butts, but also can will begin as being pressed into of axial region 121 when finishing to the plastic working of lip part 122 by the 131b of plastic working portion.If be pressed into the ca(u)lk operation that the moment that finishes fully begins lip part 122, then also can further improve the retention force that produces by ca(u)lk portion 123.Under this situation, be pressed into downwards independently, cut apart the 4th anchor clamps 134 in order to make axial region 121 and the 131b of plastic working portion, and for drive independently respectively (moving up and down) they, need the driving mechanism of a plurality of systems.

In addition, in this embodiment, the restriction of the lip part 122 that will form by second anchor clamps 132 and the 3rd anchor clamps 133 be located at when beginning axial region 121 be pressed into beginning after, but also can be the time with the restriction beginning be pressed into be made as when beginning consistent.Perhaps if be purpose to correct by being pressed into the position deflection that causes, also can than before being pressed into when finishing slightly or be pressed into finish after, the stage begins restriction (rectification) arbitrarily in the ca(u)lk operation.

In addition, in this embodiment, for the amount of being pressed into that obtains to stipulate, to axial region 121 being pressed into the hole of lip part 122, and the situation that the 131b of plastic working portion is dropped to till the position of upper-end surface 132a butt of the lower end surface 121c of axial region 121 and second anchor clamps 132 is illustrated, but described being pressed into and a ca(u)lk mode example only.For example, be purpose with the skew that remedies by axial region 121 and lip part 122, tolerance of size (mean value, perhaps its allowed band) that each course of working was produced, also can the power that is pressed into when axial region 121 is pressed into lip part 122 set ca(u)lk power.

In addition, the present invention is not limited to the illustrated structure of Figure 14, also applicable hydrodynamic bearing device with other structure.

For example, in the illustrated structure of Figure 14, outer circumferential face with axial region 121 has been described as radial bearing surface 121a, the situation that the upper-end surface 122a and the lower end surface 122b of lip part 122 used as the thrust shaft bearing surface respectively, but be not limited thereto.For example, also the present invention can be applicable among both sides' end face 122a, the 122b, only the spindle unit that upper-end surface 122a is used as the hydrodynamic bearing device of the structure of thrust shaft bearing surface use.

Figure 22 represents to have only with the sectional drawing of upper-end surface 122a as the hydrodynamic bearing device 151 of the structure of thrust shaft bearing surface use.The characteristic point of this hydrodynamic bearing device 151 (with the main difference point of the described hydrodynamic bearing device 101 of Figure 14) is as follows.Promptly, in hydrodynamic bearing device 151, the hub 153 that is fixed in the upper end (opposition side of lip part 122) of axial region 121 mainly has: be positioned at the round plate 153a of opening side (upside) of housing 157 and the cylindrical portion 153b that extends to axial below from the peripheral part of round plate 153a.In addition, be provided with the dynamic pressure groove arrange regional (spiral towards opposite) of the arrangement mode that for example is shown in Figure 16 at the upper-end surface of housing 157 157c, and the lower end surface 153a1 of the 153a of opposite circular portion between form the thrust bearing gap of second T22 of thrust bearing portion.

The periphery of housing 157 form oriented above the sealing surface 157d of the taper of hole enlargement gradually.Form the radial direction size between the sealing surface 157d of this taper and the inner peripheral surface 153b1 of cylindrical portion 153b from the inaccessible side (below) of housing 157 seal space S2 to the diminishing ring-type of opening side (top).And, among Figure 22, the inner peripheral surface 157a of housing 157 and stationary plane 157b respectively with Figure 14 in the inner peripheral surface 107a and the stationary plane 107b of housing 107 corresponding.Structure in addition is identical with the described structure of Figure 14, therefore omits explanation.

So, even only under the situation of upper-end surface 122a with lip part 122 as the use of thrust shaft bearing surface, be pressed into and ca(u)lk by using simultaneously, and the portion of overflowing that week is provided with in the 122a of the upper-end surface of lip part 122 is implemented ca(u)lk processing, the baneful influence that ridge is caused the bearing surface precision is suppressed to less, thereby can keep the surface accuracy of radial bearing surface 121a or thrust shaft bearing surface etc. and the squareness between described bearing surface to heavens.Certainly, utilization is pressed into ca(u)lk and can accesses the spindle unit 102 with high constant intensity.

And, in the above description, all housing 107,157 and bearing sleeve 108 are provided with independently, but the parts more than 2 integrated each other (form by same material, perhaps embed a side parts and contour forming the opposing party's parts) that also can be in the scope that can assemble will from the parts group of the fixed side that constitutes described hydrodynamic bearing device 101,151, select.For example in structure shown in Figure 14, can be integrated between housing 107 and bearing sleeve 108, housing 107 and cover 109, housing 107 and the sealed member 110.Also can with housing 107 and bearing sleeve 108, and sealed member 110 integrated.In addition, in the structure shown in Figure 22, housing 157 and bearing sleeve 108 perhaps can be integrated between housing 157 and the cover 109.Certainly, has the also applicable the present invention of spindle unit who is provided with the lip part of sealing surface in periphery for one.

Below, based on Figure 24～Figure 31 the 3rd mode of execution of the present invention is described.At this, the 3rd mode of execution relates to an example of the mode of execution of a third aspect of the present invention.

Figure 24 represents to possess the sectional drawing of spindle motor of the hydrodynamic bearing device 301 of the 3rd mode of execution of the present invention.This spindle motor for example uses as the disk drive motor that possesses the HDD of disk, possesses: the supporting of non-contact diametrically is equipped with the hydrodynamic bearing device 301 of the spindle unit 302 of hub 303; For example by the drive portion 304 that constitutes across the relative stator coil 304a in the gap of radial direction and rotor magnet 304b; Carriage 305.Stator coil 304a is fixed in carriage 305, and rotor magnet 304b is fixed in hub 303.The housing 7 of hydrodynamic bearing device 301 is fixed in the interior week of carriage 305.In addition, as shown in the drawing, dish 306 (among Figure 24 being two) remain in hub 303.In the spindle motor that so constitutes, when when stator coil 304a switches on, make rotor magnet 304b rotation by the excitation power that produces between stator coil 304a and the rotor magnet 304b, and accompany therewith, remain in the dish 306 and the rotation of spindle unit 302 one of hub 303.

Figure 25 represents hydrodynamic bearing device 301.This hydrodynamic bearing device 301 mainly possesses: the cover 309 of an end of housing 307, the bearing sleeve 308 that is fixed in the interior week of housing 307, inaccessible housing 307, the sealed member 310 that sets in the other end opening side of housing, carry out counterrotating spindle unit 302 with respect to housing 307 and bearing sleeve 308 and sealed member 310.

Housing 307 for example forms tubular by metallic material such as brass or resin material, and is the form with its axial both ends open.The outer circumferential face 308c of bearing sleeve 308 for example by bonding (comprise gap bonding and be pressed into bonding), be pressed into, deposited (comprising ultrasonic wave coating and laser cladding) wait the method that suits to be fixed on the inner peripheral surface 307a of housing 307.In addition, be formed with than the big footpath of inner peripheral surface 307a and be used for fixing the stationary plane 307b of cover 309 described later in the lower end side of inner peripheral surface 307a.

The porous plastid that bearing sleeve 308 for example is made of sintering metal forms cylindric.In this embodiment, bearing sleeve 308 is formed cylindric by the porous plastid that with copper is the sintering metal of primary coil, and is adhesively fixed in the inner peripheral surface 307a of housing 307.In addition, bearing sleeve 308 also can be formed by the porous plastid that nonmetallic material such as resin or pottery constitute, in addition, except that porous plastids such as sintering metal, also can be by not with inner emptying aperture or have the material of structure that lubricant oil can't pass in and out the emptying aperture of degree size and form.

Be formed with in whole of the inner peripheral surface 308a of bearing sleeve 308 or a part of cylinder zone arranged a plurality of dynamic pressure grooves the zone as the radial dynamic pressure generating unit.In this embodiment, for example as shown in figure 26, a plurality of dynamic pressure groove 308a1 that the tilt angle is different mutually, the zone that 308a2 is arranged in the herringbone shape are formed on two positions in the axial direction separatedly.And, in this embodiment,, dynamic pressure groove 308a1, the 308a2 of a side (is upside at this) formed the zone form on axle direction asymmetric for circuit purpose with the lubricant oil that forms bearing inside wittingly.If describe in the illustrated mode of Figure 26, then the dynamic pressure groove 308a1 of axial centre m3 upside (sealed member 310 sides) the axial dimension X31 that forms the zone forms dynamic pressure groove 308a2 than downside to form the axial dimension X32 in zone bigger.

For example as shown in figure 27, as the thrust dynamic pressure generating section, be formed with at whole of the lower end surface of bearing sleeve 308 308b or a part of annular section a plurality of dynamic pressure groove 308b1 are arranged in spiral-shaped zone.It is opposed with the upper-end surface 322a of lip part described later 322 with the state of finished product that this dynamic pressure groove 308b1 forms the zone, when spindle unit 302 rotations, and the thrust bearing gap (with reference to Figure 25) of formation first T31 of thrust bearing portion described later between the 322a of upper-end surface.

Be formed with to axially extended a plurality of axial groove 308c1 at the outer circumferential face 308c of bearing sleeve 308.These axial grooves 308c1 functions as follows: main when the use of hydrodynamic bearing device 301, the situation of the mistake quantity not sufficient of generation lubricant oil is inferior in bearing interior space, is used for as soon as possible this defective mode being returned to suitable state.

The cover 309 of the lower end side obturation of housing 307 is for example formed by metallic material or resin material, and be fixed in the stationary plane 307b that is provided with in interior all lower ends of housing 307.At this moment, fixation method can with bearing sleeve 308 similarly use bonding, be pressed into, welding, arbitrary method such as deposited.

The dynamic pressure groove that is formed with the arrangement mode (direction of spiral is opposite) that for example is same with Figure 27 in whole of the upper-end surface of cover 309 309a or a part of zone forms the zone, as the thrust dynamic pressure generating section.It is opposed with the lower end surface 322b of the state of finished product and lip part 322 that this dynamic pressure groove forms zone (thrust dynamic pressure generating section), when the rotation of spindle unit 302, and lower end surface 322b between form the thrust bearing gap (with reference to Figure 25) of second T32 of thrust bearing portion described later.

In the present embodiment, form independently by metallic material or resin material and housing 307 as the sealed member 310 of sealing mechanism, and by be pressed into, week in the upper end that arbitrary method such as bonding, deposited, welding is fixed in housing 307.

Sealing surface 310a in that being formed with in interior week of sealed member 310 is taper forms seal space S3 between the outer circumferential face of sealing face 310a and axial region described later 321.Lubricant oil is full of under the state of hydrodynamic bearing device 301 inside, and the pasta of lubricant oil is always maintained in the scope of seal space S3.

Spindle unit (shaft member for fluid bearing device) 302 is made of axial region 321, the lip part 322 that is pressed into the ring-type of the lower end of being fixed in axial region 321.In this embodiment, as shown in figure 25, in the periphery of axial region 321, at two places radial bearing surface 321a is set separatedly vertically, this radial bearing surface 321a forms regional relative with dynamic pressure groove 308a1, the 308a2 of the inner peripheral surface 308a that is arranged at bearing sleeve 308.Between described radial bearing surface 321a, 321a, be provided with the diameter specific diameter to the little withdrawing slot part 121b of bearing surface 321a.And, consider intensity and sliding properties, axial region 321 is formed by harder materials such as SUS steel, and lip part 322 main consideration processabilities, is formed by the material of brass geometric ratio softer, but is not limited to this combination, also can at random select the material of each parts.

Assembled after the above-mentioned structure member,, thereby obtained hydrodynamic bearing device 301 as finished product to bearing interior space packing lubrication oil.At this, can use various lubricant oil as the lubricant oil that is full of in hydrodynamic bearing device 301 inside, but when the lubricant oil that offers the Hydrodynamic bearing apparatus that disk drive device such as HDD uses considers that it uses or the temperature variation in when conveying, suitable to use low relative evaporation and the good ester of low viscosity be lubricant oil, for example dioctyl sebacate (DOS), dioctyl azelate (DOZ) etc.

In the hydrodynamic bearing device 301 of said structure, when spindle unit 302 rotation, dynamic pressure groove 308a1, the 308a2 of the both sides of bearing sleeve 308 forms the zone across the radial bearing gap and relative with radial bearing surface 321a, the 321a of axial region 321.And, follow the rotation of spindle unit 302, even form in the zone at up and down any dynamic pressure groove 308a1,308a2, lubricant oil is pressed into towards the axial centre m2 of dynamic pressure groove 308a1,308a2, its pressure rises.Utilize the dynamic pressure effect of this kind dynamic pressure groove 308a1,308a2, rotating freely diametrically, first R31 of radial bearing portion and second R32 of radial bearing portion of non-contact supporting shaft part 302 are formed on two positions respectively in the axial direction separatedly.

Meanwhile, form the thrust bearing gap between the upper-end surface 322a of zone and relative therewith lip part 322 at the dynamic pressure groove 308b1 that is provided with on the 308b of the lower end surface of bearing sleeve 308 and form thrust bearing gap between the lower end surface 322b of zone and relative therewith lip part 322 at the dynamic pressure groove that is provided with on the 309a of the upper-end surface of cover 309, utilize the dynamic pressure effect of dynamic pressure groove to form the oil film of lubricant oil respectively.And, utilize the pressure of these oil films, be formed in first T31 of thrust bearing portion and second T32 of thrust bearing portion of non-contact supporting shaft part 302 on the thrust direction respectively.

Below, an example of the manufacturing process of spindle unit 302 is described based on Figure 28 A～Figure 28 C.

The spindle unit 302 of said structure forms via following operation, that is: the bottom of axial region 321 is pressed into the operation of the hole 322c that lip part 322 is provided with and be pressed into finish after, correct the operation of lip part 322 with respect to the posture of axial region 321.

Figure 28 A～Figure 28 C conception is represented the example that be pressed into operation and correction process of axial region 321 with respect to lip part 322.The axial region 321 before for example Figure 28 A represents to be pressed into and the configuration relation of lip part 322, the tubular inner peripheral surface 331a inside that axial region 321 inserted and remained in first anchor clamps 331.In addition, lip part 322 remains in the lower end surface 331b of first anchor clamps 331 and between the upper-end surface 332a of second anchor clamps 332 below first anchor clamps 331.

At this, the upper-end surface 332a that is arranged at the tubular inner peripheral surface 331a and the lower end surface 331b of first anchor clamps 331 and is arranged at second anchor clamps 332 all with the bearing surface butt of spindle unit 302, and correct the surface accuracy and the accuracy to shape of described bearing surface.Therefore, need to tubular inner peripheral surface 331a and lower end surface 331b, and upper-end surface 332a implement retrofit accurately.

In addition, in this kind spindle unit 302, in view of the squareness between radial bearing surface 321a and the thrust shaft bearing surface (upper-end surface 322a) influences this point of bearing performance, expectation is by processing the squareness that improves between tubular inner peripheral surface 331a and the lower end surface 331b in advance accurately.Certainly, in order between the lower end surface of axial restraint lip part 322 331b and upper-end surface 332a, to obtain high parallelism, need process, dispose the anchor clamps 331,332 of both sides accurately.As an example, the internal diameter size of tubular inner peripheral surface 331a is processed into the big 3 μ m of the external diameter～7 μ m than the axial region 321 that should be pressed into.In addition, it is below the 3 μ m that processing makes the squareness between tubular inner peripheral surface 331a and lower end surface 331b and tubular inner peripheral surface 331a and the upper-end surface 332a, and sets described anchor clamps 331,332.

In the state before being pressed into, the outside dimension of axial region 321 is set at bigger than the internal diameter size of the hole 322c of lip part 322, and the value that deducts from the outside dimension of axial region 321 behind the internal diameter size of hole 322c is the amount of being pressed into of essence.At this, for example carry out the size of each parts and set, so that the diameter amount of the amount of being pressed into is 10 μ m below the above 30 μ m, below the above 20 μ m of preferred 15 μ m.And, in this embodiment, be formed with chamfered section 321d, 322d respectively at the side end that is pressed into of the hole 322c that is pressed into side end and lip part 322 of axial region 321.Shown in Figure 28 A, in the stage before being pressed into, be arranged on the chamfered section 321d of axial region 321 and be arranged on lip part 322 chamfered section 322d butts.

As mentioned above, from axial region 321 and lip part 322 being arranged at the state in first anchor clamps 331 and second anchor clamps 332, make first pressing component 333 with suitable driving mechanism, and push axial region 321 (with reference to Figure 28 B).Thus, beginning axial region 321 being pressed into respect to lip part 322.And, during the pushing of axial region 321, utilize the interaction of the chamfered section 322d of the chamfered section 321d of axial region 321 of mutual butt and lip part 322, carry out coaxial involutory (mainly in the horizontal direction) of lip part 322 with respect to axial region 321.

So, by pressing first pressing component 333, the hole 322c with respect to lip part 322 is pressed into axial region 321, and stops the decline of first pressing component 333 in the moment that being pressed into of axial region 321 finished.In this embodiment, shown in Figure 28 B, be pressed into moment of the height identical, push (being pressed into) that stops first pressing component 333 with the lower end surface 322b of lip part 322 at the lower end surface of axial region 321 321c.

And, be pressed into finish after, replace first pressing component 333, second pressing component 334 is configured in the top of first anchor clamps 331 and axial region 321, and this second pressing component 334 is descended.Thus, push first anchor clamps 331, come compression flange portion 322 (with reference to Figure 28 C) by the lower end surface 331b of first anchor clamps 331 and the upper-end surface 332a of second anchor clamps 332.Under the state of the tubular inner peripheral surface 331a that axial region 321 is remained in first anchor clamps 331, carry out described squeeze operation, thus lip part 322 with respect to the posture of axial region 321 along the shape of anchor clamps 331,332 and corrected.Concrete, radial bearing surface 321a, 321a and both ends of the surface 322a, the squareness between the 322b with thrust shaft bearing surface are improved (it is following for example to be improved to 5 μ m) respectively.In addition, simultaneously, the both ends of the surface 322a of lip part 322,322b are corrected, and improve their surface accuracy and accuracy to shape (being parallelism at this).

So, after axial region 321 is pressed into respect to lip part 322, utilize anchor clamps 331,332 to apply corrective force,, can suitably correct crooked etc. by distortion that is pressed into generation and posture by correcting the posture of lip part 322 with respect to axial region 321.Especially, as this mode of execution,, can correct the both ends of the surface 322a, the 322b that relatively are easy to generate the lip part 322 of distortion owing to the difference of material or shape effectively by lip part 322 is applied corrective force.From as can be known above, the radial bearing surface 321a that is provided with at axial region 321 or lip part 322, the precision of thrust shaft bearing surface (both ends of the surface 322a, 322b) are good, in addition, can access the good spindle unit 302 of squareness between these bearing surfaces.

In addition, in this embodiment, be pressed into finish after, correct the posture of lip part 322 with respect to axial region 321.So, as long as correct after finishing being pressed into, can form separately with correcting employed mechanism (particularly driving mechanism) being pressed into employed mechanism, therefore for example, can apply the bigger load (corrective force) of load that is produced than first pressing component 333 lip part 322.Thus, the size of corrective force be can freely adjust, can mode or the corresponding suitable corrective force of its size be applied and be pressed into axial region 321 and lip part 322.

In addition, in this embodiment, by correcting to applying corrective force near the embedding area of lip part 322 or its.As mentioned above, be pressed into the distortion of the parts of following any one party at least and carry out, especially, in embedding area, be easy to generate local plastic deformation.Therefore, comprise as both ends of the surface 322a, the 322b of the inner circumference edge of embedding area or its lip part that closely is close to 322 all by first anchor clamps 331 and the compression of second anchor clamps 332, can more effectively correct, and can correct the distortion of lip part 322 self and lip part 322 anchor accurately with respect to axial region 321.

In addition,, correct after finishing so long as be pressed into as this mode of execution, corrective force apply direction and the structure relevant with this operation is any.For example as shown in the figure, by being pushed, can implement first anchor clamps 331 that keep axial region 321 and lip part 322 beyond the rectification of lip part 322, by second anchor clamps 332 or the anchor clamps crimping (pushing) corresponding with it also can be realized correcting in the lip part 322 that is kept by first anchor clamps 331.

And, in the manufacturing process shown in Figure 28 A～Figure 28 C, illustrated and after being pressed into of axial region 321 finished, carried out the situation of lip part 322 with respect to the rectification of the posture of axial region 321, but in the stage in addition, for example in the process that is pressed into, also can carry out rectification with respect to axial region 321 and lip part 322.

Figure 29 A～Figure 29 C conception is represented the operation that is pressed into of relevant this example.In this example, shown in Figure 29 A, first anchor clamps 331 that keep axial region 321 and with axial region 321 between the pressing component 345 that lip part 322 sides are pressed into, set the 3rd anchor clamps 344.These anchor clamps 344 and below first anchor clamps 341 between elastomer 343 is set (except that O type ring etc., also comprise spring etc.), be subjected at the 3rd anchor clamps 344 under the situation of the load downward, should load via elastomer 343 and transmit to first anchor clamps 341 from pressing component 345.In addition, under this situation, elastomer 343 compresses according to load, thereby absorbs the 3rd anchor clamps 344 displacement downwards.

Cover the periphery of lip part 322 in this embodiment with second anchor clamps 342 of the lower end surface 322b butt of lip part 322, when being pressed into, and the moving of limit flange portion 322 between first anchor clamps 331.Under this situation, work with chamfered section 321d, the 322d that lip part 322 is provided with, promptly and the gap of degree that can the some contrapositions of along continuous straight runs is set between the lip part 322 in order to make at axial region 321.All carry out retrofit accurately with the tubular inner peripheral surface 341a of first anchor clamps 341 of radial bearing surface 321a, 321a or thrust shaft bearing surface (both ends of the surface 322a, 322b) butt and the upper-end surface 342a of the lower end surface 341b and second anchor clamps 342.As concrete machining accuracy, can enumerate the identical numerical value of manufacturing process with Figure 28 A～Figure 28 C.

State in the use under the situation of device of structure, axial region 321 carries out with the fixing following of lip part 322.

At first, from the state shown in Figure 29 A, utilize suitable driving mechanism that pressing component 345 is descended.And, by pressing the axial region 321 with pressing component 345 butts, beginning being pressed into to lip part 322.This stage (when being pressed into beginning), the opposite sides that are pressed into side end of axial region 321 are in the state of giving prominence to than the 3rd anchor clamps 344 (with reference to Figure 29 A).

So, after beginning to be pressed into, in the stage after axial region 321 is pressed into the specific length amount (for example, axial region 321 is pressed into the stable posture after-stage with respect to lip part 322), make pressing component 345 and the 3rd anchor clamps 344 butts (stage shown in Figure 29 B).And, descend by further making pressing component 345, push the 3rd anchor clamps 344 downwards, thereby, transmit downward load to first anchor clamps 341 via elastomer 343.Thereby, in the time of both ends of the surface 322a, 322b by first anchor clamps 341 and second anchor clamps, 342 compression flange portions 322, carry out being pressed into of axial region 321.

So, by pressing pressing component 345,322c is pressed into axial region 321 to the hole of lip part 322, simultaneously, by the big corrective force (being the elastic recovery power of elastomer 343) that lip part 322 is applied regulation, correct the posture of lip part 322 with respect to axial region 321 at this.And, finish the moment that is pressed into lip part 322 at axial region 321, stop the decline of pressing component 345.The lower end surface 321c that Figure 29 C is illustrated in axial region 321 arrives the state that is pressed into that stops axial region 321 with the moment of the lower end surface 322b equal height of lip part 322.At this, the radial bearing surface 321a of the axial region 321 of the product that are pressed into that obtain (spindle unit 302) and end faces of both sides 322a, the squareness between 322b of lip part 322 are remedied to respectively below the 5 μ m.

So, beginning axial region 321 is pressed into respect to lip part 322, and the stage after being pressed into to a certain degree, corrects the posture of lip part 322 with respect to axial region 321, can suitably correct the crooked etc. of the distortion that produces by being pressed into and posture thus, implement simultaneously to be pressed into.Especially, as this mode of execution, begin to correct being pressed into midway, and be pressed into when improving corrective force to lip part 322 gradually, thereby can correct by being pressed into the distortion that produces at lip part 322 successively with little state, perhaps crooked from the posture that should have.Therefore, correct needed load as all less getting final product.

In addition, so long as described method (structure) can be implemented to be pressed into and to correct with single pressing component 345.Therefore, the driving mechanism that applies (drive system) that is used to the power that is pressed into and corrective force can make equipment cost reduce for single mechanism gets final product.In addition, also can implement to be pressed into and to correct by a series of anchor clamps 341～345 of mutual interlock, therefore also preferred aspect productivity.

More than, Figure 28 A～Figure 28 C, and the manufacture method of Figure 29 A～illustrated shaft member for fluid bearing device 302 of Figure 29 C have been described, also can adopt the fixing means that is pressed into beyond these certainly.

Figure 30 A, 30B conception are represented the manufacture method of the spindle unit 302 that the one example relates to.What this figure was related is pressed into fixing device except that possessing first anchor clamps 351 and second anchor clamps 352, and first pressing component 353 and second pressing component, 354 these points to be with the related fixing device that is pressed into of Figure 28 A～Figure 28 C be identical structure, it is different to correct the related manufacturing process of beginning period and this figure.

That is, shown in Figure 30 A,, utilize a driving mechanism that first pressing component 353 is descended, and press the axial region 321 with this pressing component 353 butts from keep the state of axial regions 321 and lip part 322 by anchor clamps 351,352.Thus, beginning axial region 321 being pressed into to lip part 322.This stage when beginning (be pressed into), the opposition side end that is pressed into side of axial region 321 is in the state (with reference to Figure 30 A) more outstanding than first anchor clamps 351.

And, the stage after being pressed into to a certain degree, use the driving mechanism different and second pressing component 354 descended with the driving mechanism that is used for first pressing component 353, and with first anchor clamps, 351 butts (state shown in Figure 30 B).In this embodiment, second pressing component 354 is positioned at the periphery of first pressing component 353, and constitutes the pressing component 353,354 of both sides is moved up and down.

And, descend by further making second pressing component 354, and push first anchor clamps 351 downwards, the both ends of the surface 322a of lip part 322,322b and second anchor clamps 352 between be compressed, meanwhile, carry out being pressed into of axial region 321.

So,, axial region 321 is pressed into the hole 322c of lip part 322, and corrects the posture of lip part 322 with respect to axial region 321 by second pressing component 354 and first pressing component 353 are pressed respectively independently.And, finishing the moment that be pressed into of axial region 321, stop the decline of first pressing component 353 for lip part 322.

So, beginning axial region 321 is with respect to being pressed into of lip part 322, and the stage after carrying out being pressed into to a certain degree, corrects the posture of lip part 322 with respect to axial region 321, thereby can suitably correct the crooked etc. of the distortion that produces by being pressed into and posture, implement simultaneously to be pressed into.In addition, as this mode of execution, if will be pressed into employed pressing component (first pressing component 353) and driving mechanism and the employed pressing component of rectification (second pressing component 354) and driving mechanism forms separately, the power that is pressed into that is formed by first pressing component 353 is not restricted, and can apply the load (corrective force) of suitable size to lip part 322.

In addition, in above illustrated example, illustrated to be pressed into the situation of the hole 322c of lip part 322 with the end of the axial region 321 of radial bearing surface 321a approximate same size, for example will be pressed into the so-called multidiameter shaft of position as path but also axial region 321 can be formed.Under this situation, till the position of the step surface by being pressed into axial region 321 and the upper-end surface 322a butt of lip part 322, can easily hold, manage and be pressed into the position.

In addition, in above illustrated example, illustrated that the amount of being pressed into regulation is pressed into the situation of the hole 322c of lip part 322 with the end of axial region 321, but for example for the also applicable the present invention of bonding being pressed into (being pressed into bonding).If be pressed into bondingly, then can utilize binder to remedy retention force, so compare, also can reduce the amount of being pressed into situation about being pressed into is only arranged.Perhaps, binder works as a kind of oiling agent when being pressed into, even under the situation of the increase amount of being pressed into, by supplying with binder in advance, can reduce the frictional force when being pressed into and is pressed into little load.In addition, example as shown, if at the importing side end of axial region 321 chamfered section 321d is set, following bonding under the situation about being pressed into, the 322b side pressure goes out to the lower end surface of lip part 322 to supply to the binder of this embedding area in advance.Therefore, the chamfered section 321d that is provided with at axial region 321 can be worked as a kind of binder storing section.

In addition, in the above description, illustrated, pushed lip part 322 by anchor clamps (first anchor clamps 331,341,351 and second anchor clamps 332,342,352) clamping keeping, limiting under the state of axial region 321, and apply the situation of corrective force, but the mode that applies of corrective force is not limited thereto.That is, divided by lip part 322 being applied corrective force beyond the above-mentioned anchor clamps, perhaps, corrective force (making the power of lip part 322 undergauge directions from periphery) by applying radial direction separately or combination apply axial corrective force and realize correcting and also can.In addition,, can realize the rectification of posture (squareness), and also can apply corrective force the both sides of axial region 321 and lip part 322 by axial region 321 is applied corrective force.

And that uses in the above explanation is pressed into fixing device nothing but an example, as long as can embody the manufacture method of spindle unit 302 of the present invention, can adopt structure arbitrarily.

In addition, the present invention is not limited to the illustrated structure of Figure 25, also applicable to the hydrodynamic bearing device of the structure with other.

For example among Figure 25, outer circumferential face with axial region 321 has been described as radial bearing surface 321a, and the situation that the upper-end surface 322a and the lower end surface 322b of lip part 322 used as the thrust shaft bearing surface respectively, but be not limited thereto.For example, only also the present invention can be applicable to the spindle unit that the hydrodynamic bearing device of the structure that the upper-end surface 322a among both sides' end face 322a, the 322b or lower end surface 322b are used as the thrust shaft bearing surface is used.

Figure 31 represents to have only with the sectional drawing of upper-end surface 322a as the hydrodynamic bearing device 371 of the structure of thrust shaft bearing surface use.The characteristic point of this hydrodynamic bearing device 371 (with the main difference point of the described hydrodynamic bearing device 301 of Figure 25) is as follows.Promptly, in hydrodynamic bearing device 371, the hub 373 that is fixed in the upper end (opposition side of lip part 322) of axial region 321 mainly has: be positioned at the round plate 373a of opening side (upside) of housing 377 and the cylindrical portion 373b that extends to axial below from the peripheral part of round plate 373a.In addition, the dynamic pressure groove that is provided with the arrangement mode that for example is shown in Figure 27 at the upper-end surface of housing 377 377c forms zone (spiral towards opposite), and the lower end surface 373a1 of the 373a of opposite circular portion between form the thrust bearing gap of second T32 of thrust bearing portion.

The periphery of housing 377 be formed with towards above the sealing surface 377d of the taper that enlarges gradually of diameter.Between the inner peripheral surface 373b1 of the sealing surface 377d of this taper and cylindrical portion 373b, form the seal space S3 of ring-type, the seal space S3 of this ring-type from the inaccessible side (below) of housing 377 to opening side (top) reduced radius direction size gradually.And among Figure 31, the inner peripheral surface 377a of housing 377 and stationary plane 377b correspond respectively to the inner peripheral surface 307a and the stationary plane 307b of the housing 307 among Figure 25.Structure in addition is identical with the described structure of Figure 25, so omit explanation.

So, even only under the situation of upper-end surface 322a with lip part 322 as the use of thrust shaft bearing surface, be pressed into finish after or in the process of press in, a side or both sides to axial region 321 and lip part 322 apply corrective force, can access and have high constant intensity, and the surface accuracy of bearing surface is good, and the spindle unit 302 that has high squareness between radial bearing surface 321a and thrust shaft bearing surface (upper-end surface 322a).

And, in the above description, all housing 307,377 and bearing sleeve 308 are provided with independently, but the parts more than 2 integrated each other (form by same material, perhaps embed a side parts and contour forming the opposing party's parts) that also can be in the scope that can assemble will from the parts group of the fixed side that constitutes described hydrodynamic bearing device 301,371, select.For example in structure shown in Figure 25, can be integrated between housing 307 and bearing sleeve 308, housing 307 and cover 309, housing 307 and the sealed member 310.Also can with housing 307 and bearing sleeve 308, and sealed member 310 integrated.In addition, in the structure shown in Figure 31, housing 377 and bearing sleeve 308 perhaps can be integrated between housing 377 and the cover 309.

Below, based on Figure 32～Figure 39 the 4th mode of execution of the present invention is described.At this, the 4th mode of execution relates to an example of the mode of execution of first side of the present invention.

Figure 32 represents to possess the sectional drawing of spindle motor of the hydrodynamic bearing device 401 of the 4th mode of execution of the present invention.This spindle motor for example uses as the disk drive motor that possesses the HDD of disk, possesses: the supporting of non-contact diametrically is equipped with the hydrodynamic bearing device 401 of the spindle unit 402 of hub 403; For example by the drive portion 404 that constitutes across the relative stator coil 404a in the gap of radial direction and rotor magnet 404b; Carriage 405.Stator coil 404a is fixed in carriage 405, and rotor magnet 404b is fixed in hub 403.The housing 407 of hydrodynamic bearing device 401 is fixed in the interior week of carriage 405.In addition, as shown in the drawing, dish 406 (among Figure 32 being two) remain in hub 403.In the spindle motor that so constitutes, when when stator coil 404a switches on, make rotor magnet 404b rotation by the excitation power that produces between stator coil 404a and the rotor magnet 404b, and accompany therewith, remain in the dish 406 and the rotation of spindle unit 402 one of hub 403.

Figure 33 represents hydrodynamic bearing device 401.This hydrodynamic bearing device 401 mainly possesses: the cover 409 of an end of housing 407, the bearing sleeve 408 that is fixed in the interior week of housing 407, inaccessible housing 407, the sealed member 410 that sets in the other end opening side of housing, carry out counterrotating spindle unit 402 with respect to housing 407 and bearing sleeve 408 and sealed member 410.

Housing 407 for example forms tubular by metallic material such as brass or resin material, and is the form with its axial both ends open.The outer circumferential face 408c of bearing sleeve 408 for example by bonding, be pressed into, inner peripheral surface 407a that suitable method such as deposited is fixed on housing 407.In addition, be formed with than the big footpath of inner peripheral surface 407a and be used for fixing the stationary plane 407b of cover 409 described later in the lower end side of inner peripheral surface 407a.

The porous plastid that bearing sleeve 408 for example is made of sintering metal forms cylindric.In this embodiment, bearing sleeve 408 is formed cylindric by the porous plastid that with copper is the sintering metal of primary coil, and is adhesively fixed in the inner peripheral surface 407a of housing 407.In addition, bearing sleeve 408 also can be formed by the porous plastid that nonmetallic material such as resin or pottery constitute, in addition, except that porous plastids such as sintering metal, also can be by not with inner emptying aperture or have the material of structure that lubricant oil can't pass in and out the emptying aperture of degree size and form.

Be formed with in whole of the inner peripheral surface 408a of bearing sleeve 408 or a part of zone arranged a plurality of dynamic pressure grooves the zone as the radial dynamic pressure generating unit.In this embodiment, for example as shown in figure 34, a plurality of dynamic pressure groove 408a1 that the tilt angle is different mutually, the zone that 408a2 is arranged in the herringbone shape are formed on two positions in the axial direction separatedly.In addition, these dynamic pressure grooves 408a1,408a2 arrange regional form on axle direction its one or both sides asymmetric for the circuit purpose with the lubricant oil that forms bearing inside wittingly.If refer to the illustrated mode of Figure 34, then the axial dimension X41 of the dynamic pressure groove 408a1 arrange regional of its axial centre m4 upside (sealed member 410 sides) forms bigger than the axial dimension X42 of the dynamic pressure groove 408a2 arrange regional of downside.

For example as shown in figure 35, as the thrust dynamic pressure generating section, be formed with in whole of the lower end surface of bearing sleeve 408 408b or a part of zone a plurality of dynamic pressure groove 408b1 are arranged in spiral-shaped zone.This dynamic pressure groove 408b1 arrange regional is opposed with the upper-end surface 422a of the state of finished product and lip part described later 422, when spindle unit 402 rotations, and forms the thrust bearing gap (with reference to Figure 33) of first T41 of thrust bearing portion described later between the 422a of upper-end surface.

Be formed with to axially extended a plurality of axial groove 408c1 at the outer circumferential face 408c of bearing sleeve 408.These axial grooves 408c1 functions as follows: main when the use of hydrodynamic bearing device 401, the situation of mistakes quantity not sufficient that produces lubricant oil in bearing interior space is inferior, is used for will being somebody's turn to do as soon as possible recovering state such as quantity not sufficient and arrives suitable state.

The cover 409 of the lower end side obturation of housing 407 is for example formed by metallic material or resin material, and be fixed in the stationary plane 407b that is provided with in interior all lower ends of housing 407.At this moment, cover 409 fixing can use bonding, be pressed into, welding, arbitrary method such as deposited.

Be formed with the dynamic pressure groove arrange regional of the arrangement mode (direction of spiral is opposite) that for example is same with Figure 35 in whole of the upper-end surface of cover 409 409a or a part of zone.This dynamic pressure groove arrange regional (thrust dynamic pressure generating section) is opposed with the lower end surface 422b of the state of finished product and lip part 422, when the rotation of spindle unit 402, and lower end surface 422b between form the thrust bearing gap (with reference to Figure 33) of second T42 of thrust bearing portion described later.

In the present embodiment, form independently by metallic material or resin material and housing 407 as the sealed member 410 of sealing mechanism, and by be pressed into, week in the upper end that arbitrary method such as bonding, deposited, welding is fixed in housing 407.

Sealing surface 410a in that being formed with in interior week of sealed member 410 is taper forms seal space S4 between the outer circumferential face of sealing face 410a and axial region described later 421.Lubricant oil is full of under the state of hydrodynamic bearing device 401 inside, and the pasta of lubricant oil is always maintained in the scope of seal space S4.

Spindle unit 402 is made of axial region 421, lip part 422 that the lower end of axial region 421 is fixed on the ring-type of the hole 22c that is arranged at central authorities.As shown in figure 33, be formed with radial bearing surface 421a in the periphery of axial region 421, this radial bearing surface 421a dynamic pressure groove 408a1,408a2 arrange regional with the inner peripheral surface 408a that is arranged at bearing sleeve 408 diametrically is relative.In this embodiment, radial bearing surface 421a is arranged on two positions in the axial direction separatedly.Between described radial bearing surface 421a, 421a, be provided with the diameter specific diameter to the little withdrawing slot part 421b of bearing surface 421a.

The lower end of axial region 421 is pressed into lip part 422.In addition, the axial end portion (is bearing sleeve 408 sides at this) in axial region 421 and the chimeric zone of lip part 422 is formed with the ca(u)lk fixing part 423 with lip part 422 ca(u)lks.

And, preferably form for axial region 421 by excellent material such as stainless steel equal strength, rigidity, antifriction consumptions, in addition, compare the plastic working excellent material formation that ca(u)lk adds man-hour with axial region 421 for lip part 422 preferences such as brass etc.

Assembled after the above-mentioned structure member,, thereby obtained hydrodynamic bearing device 401 as finished product to bearing interior space (zone of representing with the some apperance of loosing among Figure 33) packing lubrication oil.At this, can use various lubricant oil as the lubricant oil that is full of in hydrodynamic bearing device 401 inside, but when the lubricant oil that offers the Hydrodynamic bearing apparatus that disk drive device such as HDD uses considers that it uses or the temperature variation in when conveying, suitable to use low relative evaporation and the good ester of low viscosity be lubricant oil, for example dioctyl sebacate (DOS), dioctyl azelate (DOZ) etc.

In the hydrodynamic bearing device 401 of said structure, when spindle unit 402 rotation, the dynamic pressure groove 408a1 of the both sides of bearing sleeve 408,408a2 arrange regional are across the radial bearing gap and relative with radial bearing surface 421a, the 421a of axial region 421.And, follow the rotation of spindle unit 402, even in up and down any dynamic pressure groove 408a1,408a2 arrange regional, lubricant oil is pressed into towards the axial centre m4 of dynamic pressure groove 408a1,408a2, its pressure rises.Utilize the dynamic pressure effect of this kind dynamic pressure groove 408a1,408a2, rotating freely diametrically, first R41 of radial bearing portion and second R42 of radial bearing portion of non-contact supporting shaft part 402 are formed on two positions respectively in the axial direction separatedly.

Meanwhile, in the thrust bearing gap between the upper-end surface 422a of dynamic pressure groove 408b1 arrange regional that is provided with on the 408b of the lower end surface of bearing sleeve 408 and relative therewith lip part 422 and the thrust bearing gap between the lower end surface 422b of dynamic pressure groove arrange regional that is provided with on the 409a of the upper-end surface of cover 409 and relative therewith lip part 422, utilize the dynamic pressure effect of dynamic pressure groove to form the oil film of lubricant oil respectively.And, utilize the pressure of these oil films, be formed in first T41 of thrust bearing portion and second T42 of thrust bearing portion of non-contact supporting shaft part 402 on the thrust direction respectively.

Below, an example of the manufacturing process of spindle unit 402 is described based on Figure 36 and Figure 37.

Figure 36 represents the skeleton diagram of the employed device of assembling of spindle unit 402.This device mainly possesses: first anchor clamps 431 that keep axial region 421; Be positioned at second anchor clamps 432 of maintenance lip part 422 of the below of first anchor clamps 431; And second anchor clamps 432 between, can keep or the 3rd anchor clamps 433 of limit flange portion 422.

In addition, in this mode of execution, above axial region 421, be equipped with the pressing component 434 that utilizes suitable driving mechanism that axial region 421 is pressed into towards lip part 422 sides, and between pressing component 434 and the 3rd anchor clamps 433, be equipped with rigid element 435 and elastomer 436, bear at rigid element 435 under the situation of the load downward, should load by elastomer 436 and transmit to the 3rd anchor clamps 433 from pressing component 434.In this case, elastomer 436 is according to load and compressive strain, thereby absorbs the compressive strain of the 3rd anchor clamps 433.

First anchor clamps 431 have the hole 431a that can insert and keep axial region 421.In addition, the upper-end surface 432a of second anchor clamps 432 keeps and limit flange portion 422 with the lower end surface 433a of the 3rd anchor clamps 433 that are positioned at its top.Thereby hole 431a need form its size and dimension accurately, can there not be radial bearing surface 421a, the 421a that keeps and limit with rocking axial region 421.Equally, upper-end surface 432a and lower end surface 433a also need to form accurately its shape (planeness etc.), can seamlessly keep and limit both ends of the surface 422a, the 422b of the lip part 422 that comprises the thrust shaft bearing surface.

In addition, in this kind spindle unit 402, the squareness between radial bearing surface 421a and the thrust shaft bearing surface (upper-end surface 422a) influences bearing performance.Therefore, in order between described bearing surface, to obtain high squareness, wish to improve between hole 431a and the upper-end surface 432a and the squareness between hole 431a and the lower end surface 433a by high-precision processing in advance.In order to obtain high parallelism between the upper-end surface 432a of limit flange portion 422 in the axial direction and the lower end surface 433a, need process both sides' anchor clamps 432,433 certainly accurately.

Be provided with the 131b of plastic working portion below first anchor clamps 431, the 131b of this plastic working portion follows the decline of first anchor clamps 431, be used for interior week of lip part 422 is implemented ca(u)lk processing, and and axial region 421 between form ca(u)lk fixing part 423.In this mode of execution, shown in Figure 37 A, the 431b of plastic working portion is being in its full week along with the shape that reduces its radial direction width dimensions towards lower end side (along with near lip part 422 sides), and is made of first conical surface 431b1 that is positioned at its outer circumferential side and second conical surface 431b2 that is positioned at all sides.

At this,, then, form the big diametral plane 422d1 bigger than the portion that the is pressed into diameter of axial region 421 at the inner peripheral surface 422c of the lip part 422 that forms the hole that should be pressed into axial region 421 if be conceived to shape with the opposed lip part 422 of the 431b of plastic working portion.At this, big diametral plane 422d1 is arranged at the upper-end surface 422a side of bearing ca(u)lk processing among the inner peripheral surface 422c, and suitably determine its internal diameter size, with and axial region 421 between form the gap (for example counting μ m～tens of μ m) of the degree of the absorption function of bringing into play distortion described later.In addition, except the amount of being pressed into of the stage anticipated requirement of internal diameter before being pressed into of the inner peripheral surface 422c of big diametral plane 422d1, and form littler than the external diameter of the underpart of the axial region 421 that should be pressed into.

In addition, in the 422a of the upper-end surface of lip part 422, be formed with on week except supposing that whole mask has a portion of overflowing that forms of the lip part 422 under the situation of smooth upper-end surface 422a.If refer to the illustrated lip part 422 of Figure 37 A, utilization constitutes the portion of overflowing via step from the plan-position identical with upper-end surface 422a to the hypomere plane 422e that established amount is moved back in 422b rear flank, lower end surface, and hypomere plane 422e and big diametral plane 422d1 link to each other via the conical surface 422d2 that all sides within it are provided with.Under this situation, axial region 421 and lip part 422 are being arranged under the state of each anchor clamps 431～433, the 431b of plastic working portion is positioned at the top of the hypomere plane 422e of lip part 422, perhaps with hypomere plane 422e butt.

Below, the example of assembling procedure of spindle unit 402 of the situation of the device that uses said structure is described.In this embodiment, the order with axial region 421, rigid element 435, first anchor clamps 131 is applied downward load, under the restriction of lip part 122, carry out essence be pressed into and the situation of ca(u)lk processing describes.

At first,, pressing component 434 is descended, the lower end of axial region 421 is pressed into the hole of lip part 422 from state as shown in figure 36.And, in be pressed into stage stable posture after of axial region 421, begin to utilize pressing component 434 that rigid element 435 is pressed into downwards, thereby, transmit downward load to the 3rd anchor clamps 433 by elastomer 436 with respect to lip part 422.Thereby, under the state of both ends of the surface 422a, the 422b of limit flange portion 422, carry out being pressed into of axial region 421 between by the 3rd anchor clamps 433 and second anchor clamps 432.

So, under the state that has limited lip part 422, proceed being pressed into of axial region 421, be pressed into the stage of having finished certain degree at this, make pressing component 434 and first anchor clamps, 431 butts, first anchor clamps 431 are pressed into to the hypomere plane of lip part 422 422e (overflowing portion).So, by implementing plastic working (ca(u)lk processing) to overflowing portion, form and the recess 422f of the shape that the 431b of plastic working portion is similar in the part that is subjected to ca(u)lk processing by the 431b of plastic working portion of the lower end that is arranged at first anchor clamps 431.In addition, utilize the plastic flow (plastic deformation) of inside all sides of following the formation of recess 422f and producing, the gap between big diametral plane 422d1 and the axial region 421 is filled by the part, and the part of lip part 422 is pushed to axial region 421.Thus, and the gap position adjacent that remains between lip part 422 and the axial region 421 form ca(u)lk fixing part 423.Above-mentioned ca(u)lk processing continues to carry out under the restriction of lip part 422.

At this moment, the outer circumferential side at the recess 422f that forms as the hypomere plane 422e that overflows portion forms ridge (first ridge) 422g1 that is produced by ca(u)lk processing.In this embodiment because from the inside all lateral deviations of the external diameter end of hypomere plane 422e from the position implement ca(u)lk processing, therefore the first ridge 422g1 is created on the hypomere plane 422e between recess 422f and the upper-end surface 422a.In addition, the interior all sides at the recess 422f that is subjected to ca(u)lk processing generation form the second ridge 422g2.

So, be pressed into lip part 422 at axial region 421, and form the stage behind the ca(u)lk fixing part 423 between axial region 421 and the lip part 422, stop the decline of pressing component 434, from anchor clamps 431～433, take out the one builtup member of axial region 421 and lip part 422, obtain spindle unit 402 as finished product.In this embodiment, the stage of (after making lip part 422 plastic deformations) till the position of the upper-end surface 432a butt of the lower end surface 421c that first anchor clamps 431 is pushed into axial region 421 and second anchor clamps 432, stop pressing component 434, take out builtup member (spindle unit 402).

So, axial region 421 is pressed into lip part 422, and utilize ca(u)lk processing to make lip part 422 plastic deformation partly, form ca(u)lk fixing part 423 thus and between the axial region 421, thereby, can between axial region 421 and lip part 422, apply by fastening force that is pressed into generation and the fastening force that produces by ca(u)lk, and can realize the raising of constant intensity.In addition, the distortion of lip part 422 (plastic deformation) is local get final product, therefore, can keep the high accuracy to shape (squareness) that obtains when being pressed into, perhaps the state raising of realization constant intensity down of the high surface accuracy that obtains during each component processing.

In addition, be provided as the big diametral plane 422d1 of large-diameter portion at the inner peripheral surface 422c of lip part 422, and in the state after being pressed into axial region 421, and produce the gap between the outer circumferential face of axial region 421, and, come this gap of landfill by the distortion of processing the lip part 422 that is produced by ca(u)lk.So, by carrying out ca(u)lk processing, the distortion (plastic flow) that adds the lip part 422 that produces man-hour at ca(u)lk is absorbed in the gap of big diametral plane 422d1 and axial region 421, reduces from the part (is recess 422f at this) that the is subjected to ca(u)lk processing amount of deformation to outer circumferential side.Therefore, can avoid encouraging the distortion such as warpage that cause in lip part 422 all generations by being pressed into by any end face (being upper-end surface 422a at this) being carried out ca(u)lk processing, and can keep planeness respectively accurately as the upper-end surface 422a and the lower end surface 422b of thrust shaft bearing surface, perhaps with the squareness of axial region 421.

In addition, as this mode of execution, by form the gap of big diametral plane 422d1 and axial region 421 in interior all sides (radial direction inboard) of the recess 422f that is processed to form by ca(u)lk, add man-hour at ca(u)lk, towards axial region 421 sides, plastic deformation becomes and is easy to generate, and further alleviates the distortion to outer circumferential side.Thus, suppress upper-end surface 22a as possible and expanded, can reduce the distortion of lip part 422 integral body to the periphery side pressure.Especially, in this mode of execution, to and axial region 421 between should form the zone of ca(u)lk fixing part 423 and the lip part 422 that is pre-formed big diametral plane 422d1 is implemented to be pressed into and ca(u)lk processing, so be pressed into fixing zone not forming, can utilize ca(u)lk processing to form ca(u)lk fixing part 423, and can obtain utilizing the retention force of these ca(u)lk fixing part 423 generations effectively in the distortion of interior all side generations of lip part 422.

In addition, in this embodiment, in the 422a of the upper-end surface of lip part 422, set in advance in week as overflowing the hypomere plane 422e of portion, and this hypomere plane 422e is carried out ca(u)lk process, therefore the plastic flow that is produced by ca(u)lk processing is formed on the portion of overflowing (step of upper-end surface 422a and the hypomere plane 422e) absorption on every side of recess 422f.Therefore, can reduce the amount of the plastic deformation (plastic flow) that produces to the outer circumferential side of recess 422f, and the height of the first ridge 422g1 can be suppressed for lower.Especially, as this mode of execution, under the first ridge 422g1 is formed on situation on the 422e of hypomere plane, the first ridge 422g1 can be suppressed the step amount of hypomere plane 422e and upper-end surface 422a towards bearing sleeve 408 side-prominent amounts than thrust bearing.Thus, relax or eliminate the interference of the first ridge 422g1, thereby can bring into play good bearing performance the thrust shaft bearing surface.Specifically,, more preferably be made as below the 2 μ m, can avoid interference, thereby guarantee good bearing performance the essence of bearing performance by the first ridge 422g1 is located at below the 3 μ m from the projecting height of thrust shaft bearing surface.

In addition, in this embodiment, in being pressed into operation and ca(u)lk operation, the state with the both sides' of limit flange portion 422 end face 422a, 422b carries out ca(u)lk processing at least, therefore can carry out ca(u)lk with the posture of the axial region 421 of keeping lip part 422 when being pressed into.In addition, can carry out ca(u)lk with the state of the surface accuracy of the both sides' that keep restriction end face 422a, 422b.Especially, as this mode of execution,, follow the slippage of pressing component 434 and rigid element 435 in employing and under the situation of the structure that increases, come limit flange portion 122 by the fashionable high restraint of specific pressure to the load (restraint) of lip part 422.Therefore, even, utilize the restriction of anchor clamps 431～433 to come the offset of house of correction rheme to move just in case when being pressed into, produced between axial region 421 and the lip part 422 under the situation of position deflection etc.

In addition, in this embodiment, even when being pressed into, utilize second and third anchor clamps 432,433 to come limit flange portion 422, so, be pressed into axial region 421 when perhaps correcting the planeness of both ends of the surface 422a, 422b of lip part 422 and deflection precision (squareness) suitably to keep the state that is pressed into posture of axial region 421 with respect to lip part 422.In addition, if be pressed into suitably keeping being pressed under the state of posture, then there is not the problem that produces the position deflection after being pressed into, so preferred.

In addition,, carry out under the situation about being pressed into of axial region 421, can under the state of the amount of being pressed into that obtains a great deal of, carry out, on the other hand, also can adopt to have made up to be pressed into and bonding fixation method following rectification as this mode of execution.Will be pressed into bonding coefficient situation under, can utilize binder realize to strengthen constant intensity, gently be pressed into etc. so can adopt.If the amount of being pressed into is little can be finished, then correspondingly form good assembly precision easily, thus fixing by following ca(u)lk to be pressed into, can be fixed the very good spindle unit 402 of intensity and accuracy to shape (assembly precision).

More than, illustrated that the 4th mode of execution of the present invention relates to a structure example and manufacturing process's example of spindle unit 402, but be not limited thereto certainly, also can adopt above-mentioned structure and operation in addition.

In for example above-mentioned mode of execution, illustrated with big diametral plane 422d1 to constitute situation with the gap of the outer circumferential face of axial region 421, also can adopt mode in addition certainly in the 422a side setting of the upper-end surface of inner peripheral surface 422c.That is,, can adopt shape, configuration mode arbitrarily as long as can absorb the plastic deformation that is produced by ca(u)lk processing with the gap that between axial region 421 and large-diameter portion, forms by being pressed into to lip part 422.Figure 38 A represents the one example, is formed with undercut groove 422d3 as large-diameter portion at the inner peripheral surface 422c of the lip part 422 that should be pressed into axial region 421.At this, undercut groove 422d3 forms, its part be positioned at the recess 422f that is subjected to ca(u)lk processing and forms axially under.

Under this situation, shown in Figure 38 B, absorb by the undercut groove 422d3 of the inboard, below that is positioned at recess 422f and the gap of axial region 421 to interior all side generation distortion of the part (recess 422f) that is subjected to ca(u)lk processing or the distortion (plastic flow) that produces towards axial below.Thereby, can will suppress for less to the distortion that its outer circumferential side produces, and can keep the shape of the lip part 422 that comprises the thrust bearing face well by ca(u)lk processing.

Certainly, as long as can absorb the plastic deformation of the lip part 422 that is produced by ca(u)lk processing, the gap between lip part 422 and the axial region 421 is not essential.For example, in being pressed into state, also can be formed with hollow portion, and absorb the distortion of the lip part 422 that produces by ca(u)lk processing with this hollow portion at lip part 422.Hollow portion also can by for example follow axial region 421 be pressed into and the part of the inner peripheral surface 422c of inaccessible lip part 422 forms.

And in arbitrary mode, the part (gap, hollow portion) that absorbs distortion is preferably forming uniform shape entirely in week.In addition, in this case, ca(u)lk processing is implementing at the upper-end surface of lip part 422 422a in full week preferably.With described structure and processing mode, the distortion of lip part 422 is formed more even, can further improve the precision of thrust shaft bearing surface.

In addition, in the above description, illustration constitute the situation of the portion of overflowing by upper-end surface 422a and the hypomere plane 422e that forms via step, as long as having that the protuberance (the first ridge 422g1) that the outer circumferential side at recess 422f is produced suppresses is lower effect, also can adopt variety of way.For example omit diagram, also can constitute the portion of overflowing by a plurality of conical surfaces.In this case, consider that the conical surface of outer circumferential side links to each other with upper-end surface 422a in its outer circumference end, and the conical surface of the interior all sides continuous structure of Zhou Duanyu inner peripheral surface 422c (perhaps big diametral plane 422d1) within it.

In addition,, also be not limited to above-mentioned example, can adopt mode arbitrarily about the 431b of plastic working portion.

In addition, in this embodiment, illustration ca(u)lk fixing part 423 is arranged on the situation of axial region 421 and the upper axial end (upper-end surface 422a side) of the embedding area of lip part 422, but, implement ca(u)lk processing at the suitable anchor clamps of the interior Zhou Liyong of the lower end surface of lip part 422 422b and also can not only at upper-end surface 422a.In this case, form ca(u)lk fixing part 423, therefore can determine necessary anticreep power (retention force) or determine having or not of ca(u)lk that another is distolateral according to its purposes at the axial two ends of lip part 422.Perhaps, according to the inequality that is pressed into power, can replace the distolateral ca(u)lk power of adjusting and determine having or not of another distolateral ca(u)lk.

In addition, in this embodiment, illustrated and axial region 421 has been pressed into (being pressed into) stage till produce the plurality of gaps position between the upper-end surface 432a of the lower end surface 421c of axial region 421 and second anchor clamps 432 relative with this face, make the situation of first anchor clamps 431 and pressing component 434 butts, but also can will begin as being pressed into of axial region 421 when finishing to the plastic working of lip part 422 by the 431b of plastic working portion.If be pressed into the ca(u)lk operation that the moment that finishes fully begins lip part 422, then also can further improve the retention force that produces by ca(u)lk fixing part 423.In this case, constitute with different driving mechanisms axial region 421 and the 431b of plastic working portion are got final product by drops.

In addition, in this embodiment, the restriction of the lip part 422 that will form by second anchor clamps 432 and the 3rd anchor clamps 433 be located at when beginning axial region 421 be pressed into beginning after, but also can be the time with the restriction beginning be pressed into be made as when beginning consistent.Perhaps if be purpose to correct by being pressed into the position deflection that causes, also can than before being pressed into when finishing slightly or be pressed into finish after, the stage begins restriction (rectification) arbitrarily in the ca(u)lk operation.

In addition, in this embodiment, for the amount of being pressed into that obtains to stipulate, the hole that axial region 421 is pressed into lip part 422 has been described, and make the situation till the 431b of plastic working portion drops to the position of upper-end surface 432a butt of the lower end surface 421c of axial region 421 and second anchor clamps 432, but described being pressed into and a ca(u)lk mode example only.For example, to remedy by axial region 421 and lip part 422, tolerance of size (mean value that each course of working was produced, perhaps its allowed band) skew is a purpose, also can the power that is pressed into when axial region 121 is pressed into lip part 122 sets ca(u)lk condition (ca(u)lk load or ca(u)lk with the amount of being pressed into of anchor clamps etc.).

In addition, the present invention is not limited to above-mentioned structure, also applicable hydrodynamic bearing device with other structure.

For example, in the above-described embodiment, outer circumferential face with axial region 421 has been described as radial bearing surface 421a, the situation that the upper-end surface 422a and the lower end surface 422b of lip part 422 used as the thrust shaft bearing surface respectively, but be not limited thereto.For example, also the present invention can be applicable among both sides' end face 422a, the 422b, only the spindle unit that upper-end surface 422a is used as the hydrodynamic bearing device of the structure of thrust shaft bearing surface use.

Figure 39 represents the sectional drawing of the hydrodynamic bearing device 451 of other structure.The characteristic point of this hydrodynamic bearing device 451 (with the main difference point of the described hydrodynamic bearing device 401 of Figure 33) is as follows.Promptly, in hydrodynamic bearing device 451, the hub 453 that is fixed in the upper end (opposition side of lip part 422) of axial region 421 mainly has: be positioned at the round plate 453a of opening side (upside) of housing 457 and the cylindrical portion 453b that extends to axial below from the peripheral part of round plate 453a.In addition, be provided with the dynamic pressure groove arrange regional (spiral towards opposite) of the arrangement mode that for example is shown in Figure 35 at the upper-end surface of housing 457 457c, and the lower end surface 453a1 of the 453a of opposite circular portion between form the thrust bearing gap of second T42 of thrust bearing portion.

The periphery of housing 457 form oriented above the sealing surface 457d of the taper of hole enlargement gradually.Form the radial direction size between the sealing surface 457d of this taper and the inner peripheral surface 453b1 of cylindrical portion 453b from the inaccessible side (below) of housing 457 seal space S4 to the diminishing ring-type of opening side (top).And, among Figure 39, the inner peripheral surface 457a of housing 457 and stationary plane 457b respectively with Figure 33 in the inner peripheral surface 407a and the stationary plane 407b of housing 407 corresponding.Structure in addition is identical with the described structure of Figure 33, therefore omits explanation.

So, even only under the situation of upper-end surface 422a with lip part 422 as the use of thrust shaft bearing surface, be pressed into and ca(u)lk by using simultaneously, and carrying out ca(u)lk with the state that forms the gap between the large-diameter portion that is provided with in the interior week at lip part 422 and the axial region 421 processes, plastic deformation when reducing ca(u)lk is to the influence of the accuracy to shape of lip part 422, and can keep the surface accuracy of radial bearing surface 421a or thrust shaft bearing surface etc. and the squareness between described bearing surface to heavens.Certainly, utilization is pressed into ca(u)lk and can accesses the spindle unit 402 with high constant intensity.

And, in the above description, all housing 407,457 and bearing sleeve 408 are provided with independently, but the parts more than 2 integrated each other (form by same material, perhaps embed a side parts and contour forming the opposing party's parts) that also can be in the scope that can assemble will from the parts group of the fixed side that constitutes described hydrodynamic bearing device 401,451, select.For example in structure shown in Figure 33, can be integrated between housing 407 and bearing sleeve 408, housing 407 and cover 409, housing 407 and the sealed member 410.Also can with housing 407 and bearing sleeve 408, and sealed member 410 integrated.In addition, in the structure shown in Figure 39, housing 457 and bearing sleeve 408 perhaps can be integrated between housing 457 and the cover 409.Certainly, has the also applicable the present invention of spindle unit who is provided with the lip part of sealing surface in periphery for one.

Below, based on Figure 40～Figure 51 the 5th mode of execution of the present invention is described.At this, the 5th mode of execution relates to an example of the mode of execution of first side of the present invention.

Figure 40 conception represents to be equipped with the structure example of the information equipment of hydrodynamic bearing device with spindle motor.This spindle motor is used for disk drive devices such as HDD, possesses as main structure: rotate the hydrodynamic bearing device 501 of supporting shaft part 502 freely; Be assemblied in the dish hub 503 of spindle unit 503; For example across the gap of radial direction relative stator coil 504a and rotor magnet 504b; Carriage 505.Stator coil 504a is fixed in the periphery of carriage 505, and rotor magnet 504b is fixed in the interior week of dish hub 503.The housing 507 of hydrodynamic bearing device 501 is assemblied in the interior week of carriage 305.On dish hub 503, maintain dishes 506 such as one or more disk.In the spindle motor that constitutes by above structure, when when stator coil 504a switches on, make rotor magnet 504b rotation by the electromagnetic force between stator coil 504a and the rotor magnet 504b, thus, remain in the dish 506 and the rotation of spindle unit 502 one of dish hub 503.

Figure 41 represents the hydrodynamic bearing device 501 of the 5th mode of the present invention.Hydrodynamic bearing device 501 shown in this figure possesses: the sealed member 510 of the cover 509 of an end opening of housing 507, the bearing sleeve 508 that is fixed in the interior week of housing 507, the spindle unit 502 that is inserted into the interior week of bearing sleeve 508, enclosing housing 507, the other end opening of seal casinghousing 507.For the convenience on illustrating, with sealed member 510 sides as upside, will with its axial opposed side as downside, describe below.

Housing 507 for example forms cylindric by metallic material or resin material.Bearing sleeve 508 for example by bonding, be pressed into, inner peripheral surface 507a that suitable method such as deposited is fixed on housing 507.Be formed with cover stationary plane 507b in the lower end side of inner peripheral surface 507a than the big footpath of inner peripheral surface 507a.

Bearing sleeve 508 for example forms cylindric by the porous plastid that with copper is the sintering metal of primary coil.Except sintering metal, bearing sleeve 508 also can be formed by other porous plastid (for example porous matter resin) of soft metal materials such as for example brass or non-sintering metal.

As shown in figure 42, at the inner peripheral surface 508a of bearing sleeve 508, as the radial dynamic pressure generating unit, the zone that a plurality of dynamic pressure groove 508a1,508a2 is arranged in the herringbone shape is formed on two positions in the axial direction separatedly.In this embodiment, the dynamic pressure groove 508a1 of upside forms axially asymmetric with respect to axial centre m5 (the axial central authorities in zone between tipper up and down), and the axial dimension X51 of axial centre m5 upper-side area is bigger than the axial dimension X52 of underside area.On the other hand, the dynamic pressure groove 508a2 of downside forms axial symmetry, and its regional up and down axial dimension equates with above-mentioned axial dimension X52 respectively.By forming the dynamic pressure groove in the above described manner, during the running of bearing means, the fluid (for example lubricant oil) that is full of the gap between the outer circumferential face 521a of the inner peripheral surface 508a of bearing sleeve 508 and axial region 521 flows downwards energetically.And the dynamic pressure groove also can be formed at the radial bearing surface A of axial region 521 described later, and its shape also can form known other shape such as spirality in addition.

At the outer circumferential face 508c of bearing sleeve 508, be formed with one or many axial groove 508c1 at the both ends of the surface opening.This axial groove 508c1 is in order to make flow circulation and being provided with of the lubricant oil that is full of bearing inside, when bearing operation, and the fluid passage that lubricant oil forms by the inner peripheral surface 507a by this axial groove 508c1 and housing 507 and circulating in the bearing internal flow.Thus, remove the imbalance of bearing pressure inside, effectively avoid the leakage of lubricant oil or the generation of vibration etc.

Cover 509 for example metallic material or resin material form discoid, and utilize bonding, the cover stationary plane 507b that suitable method is fixed in housing 507 such as be pressed into.

Sealed member 510 is for example by soft metal material or other metallic material such as brass, and perhaps resin material forms ring-type, and utilize bonding, the upper end portion that suitable method is fixed in the inner peripheral surface 507a of housing 507 such as be pressed into.Between the outer circumferential face 521a of the inner peripheral surface 510a of sealing parts 510 and axial region 521, form the seal space S5 of regulation.Seal space S5 has the pooling feature that absorbs the volume-variation amount of following the temperature variation that is filled in hydrodynamic bearing device 501 lubricant oil, and in the scope of the temperature variation of imagining, the pasta of lubricant oil always is positioned at the scope of seal space S5.

Spindle unit 502 is made of axial region 521 and the thrust parts 522 that are arranged at the lower end of axial region 521, as the combination construction that all forms metal and resin.Specifically, axial region 521 is formed by metallic material, and thrust parts 522 are inserted into the metal lip part 523 of the 523c of hole portion that is arranged on the axle center by the lower end with axial region 521 and the resinous covering part 524 that covers the surface of lip part 523 constitutes.The 523c of hole portion is the both ends of the surface 523a at lip part 523, the through hole of 523b opening.In the present embodiment, axial region 521 is formed by stainless steel, and lip part 523 is by the soft metal than axial region 521 lower rigidity, and for example brass forms.

Outer circumferential face 521a at axial region 521, form radial bearing surface A, A at two positions with being separated by vertically, it is planar that described radial bearing surface A, A are level and smooth cylinder, and to form the zone relative with dynamic pressure groove 508a1,508a2 that inner peripheral surface 508a at bearing sleeve 508 is provided with diametrically.Between two radial bearing surface A, A, be formed with specific diameter to the bearing surface A withdrawing slot part 521b of path more.In addition, be described in detail later, be provided with first and second accommodation section 521c, the 521d of first and second protuberance 523d, the 523e that are used for accommodating respectively lip part 523 in the lower end of axial region 521.In the present embodiment, first and second accommodation section 521c, 521d form the groove of ring-type.

The upside end face 522a of thrust parts 522 (covering part 524) be provided with become and the downside end face 508b of bearing sleeve 508 between form the zone of the thrust shaft bearing surface B in thrust bearing gap, for example as shown in figure 43, as thrust dynamic pressure generating unit, a plurality of dynamic pressure groove 522a1 is arranged in this thrust shaft bearing surface B helical arrangement.In addition, at the downside end face 522b of thrust parts 522 (covering part 524), be provided with become and the upside end face 509a of cover 509 between form the zone of the thrust shaft bearing surface C in thrust bearing gap, omit diagram, but on thrust shaft bearing surface C, as thrust dynamic pressure generating unit, helical arrangement has a plurality of dynamic pressure grooves.And the dynamic pressure groove that is provided with at thrust shaft bearing surface B, C also can be arranged in known other shape such as herringbone shape.In addition, thrust shaft bearing surface B, C are formed on smooth surfaces, also can form the dynamic pressure groove at the downside end face 508b of bearing sleeve 508 and the upside end face 509a of cover 509.

Hydrodynamic bearing device 501 mainly is made of above structure member, and in the inner space of the housing 507 that is sealed by sealed member 510, also comprises the mood hole, inside of bearing sleeve 508, is full of lubricant oil.Can use various lubricant oil as lubricant oil, but when consider using or the temperature variation in when conveying etc., suitable low relative evaporation and low viscous ester are lubricant oil, for example, dioctyl sebacate (DOS) and dioctyl azelate (DOZ) etc.

In the hydrodynamic bearing device 501 that constitutes by above structure, when spindle unit 502 rotation, dynamic pressure groove 508a1, the 508a2 of bearing sleeve 508 form the zone, with radial bearing surface A, the A of axial region 521 between formation radial bearing gap.And, follow the rotation of spindle unit 502, the oil film that forms in the radial bearing gap utilizes the dynamic pressure effect of dynamic pressure groove 508a1,508a2 and improves its oil film rigidity, utilizes this pressure to rotate non-contact supporting shaft part 502 freely diametrically.Thus, rotating freely diametrically, the R51 of radial bearing portion, the R52 of non-contact supporting shaft part 502 are formed on two axial positions separatedly.

In addition, meanwhile,, and form the thrust bearing gap respectively between the upside end face 509a of the downside end face 508b of bearing sleeve 508 and cover 509 at thrust shaft bearing surface B, the C of thrust parts 522.And, follow the rotation of spindle unit 502, the oil film that forms in two thrust bearing gaps utilizes the dynamic pressure effect of dynamic pressure groove and improves its oil film rigidity, and utilizes this pressure to rotate non-contact supporting shaft part 502 freely on two thrust directions.Thus, be formed on and rotate first T51 of thrust bearing portion and second T52 of thrust bearing portion of non-contact supporting shaft part 502 freely on the two thrust directions.

Below, the manufacture method of the spindle unit 502 that uses is described in above-mentioned hydrodynamic bearing device 501 based on Figure 44～Figure 48 B.And spindle unit 502 is through following operation manufacturing, that is: at the assembly process of the lower end of axial region 521 holding flange portion 523 with will cover the injection forming process of covering part 524 injection mouldings on the surface of lip part 523.

(A) assembly process

Figure 44～Figure 47 conception represents lip part 523 is fixed in the example of assembly process of the lower end of axial region 521.Illustrated device mainly possesses: the ca(u)lk mould 531 that keeps axial region 521 in interior week, be positioned at ca(u)lk mould 531 below and keep the counterdie 532 of lip part 523, first intermediate die 533 of limit flange portion 523, utilize suitable driving mechanism axial region 521 to be pressed into the patrix 534 of lip part 523 sides with counterdie 532 concerted actions.In addition, between first intermediate die 533 and patrix 534, set second intermediate die 535.Between first intermediate die 533 and second intermediate die 535, elastic member 536 is set, and under the situation of bearing the load downward from patrix 534, this load transmits to first intermediate die 533 from second intermediate die 535 via elastic member 536.Elastic member 536 is according to load and compressive strain absorbs second intermediate die 535 displacement downwards thus.

And in the stage that axial region shown in Figure 44 521 and lip part 523 are set, upper and lower end face 523a, the 523b of lip part 523 presents does not have concavo-convex etc. smooth surfaces.In addition, it is little more some than the outside dimension of axial region 521 that the 523c of hole portion of lip part 523 forms diameter, going into axial region 521 with the piezometric that is pressed into of regulation.

Ca(u)lk mould 531 has retaining hole 531a and the local 531c of plastic working portion that makes lip part 523 plastic deformations that keeps axial region 521.The 531c of plastic working portion is super shape to the lower end taper, axial region shown in Figure 44 521 and lip part 523 is being formulated under the state of each mould, with the upper-end surface 523a butt of lip part 523.The lower end surface 523b of lip part 523 is kept by the upper-end surface 532a of counterdie 532, and the upper-end surface 523a of lip part 523 is kept by the lower end surface 533a of first intermediate die 533.Therefore, the retaining hole 531a of ca(u)lk mould 531 is with the retrofit accurately of its size and dimension, can suitably keep and limit radial bearing surface A, the A of axial region 521.Equally, the lower end surface 533a of first intermediate die 533 and the upper-end surface 532a of counterdie 532 suitably keep also upper and lower end face 523a, the 523b of limit flange portion 523 also with its shape (planeness etc.) retrofit accurately distinguishing.

In addition, in the spindle unit of this kind, the squareness between radial bearing surface and the thrust shaft bearing surface influences bearing performance.In the spindle unit 502 of present embodiment, the state of described squareness for when the formation of covering part 524 described later, guaranteeing, but, then be difficult to the squareness that obtains expecting if lip part 523 is too poor with respect to the fixed precision of axial region 521.Therefore, between the retaining hole 531a that expectation fully improves at ca(u)lk mould 531 and the upper-end surface 532a of counterdie 532, and the squareness between the lower end surface 533a of the retaining hole 531a of ca(u)lk mould 531 and first intermediate die 533.In addition, the parallelism between the lower end surface 533a of the upper-end surface 532a of the counterdie 532 of the both ends of the surface of the abundant raising of expectation limit flange portion 523 and first intermediate die 533.

Use the device of said structure, lip part 523 is fixed in the lower end of axial region 521 in such a way.

At first, as shown in figure 44, axial region 521 and lip part 523 are arranged on after the said apparatus, patrix 534 are descended, and make the lower end surface 534a of patrix 534 and the upper-end surface 521e butt of axial region 521.In this stage, the upper-end surface 521e that the upper-end surface 535a of second intermediate die 535 is positioned at axial region 521 is the below more, in addition the upper-end surface 531b of the ca(u)lk mould 531 upper-end surface 535a below more that is positioned at second intermediate die 535.

Then, as shown in figure 45, patrix 534 is further descended, the lower end of axial region 521 is pressed into the 523c of hole portion of lip part 523.When the lower end of axial region 521 is pressed into specific length, the upper-end surface 535a butt of the lower end surface 534a of patrix 534 and second intermediate die 535.And, if being descended, patrix 534 also pushes second intermediate die 535 downwards, then transmit downward load to first intermediate die 533 via elastic member 536.Therefore, being pressed into of axial region 521 is to carry out under by the state of first intermediate die 533 and counterdie 532 restrictions at both ends of the surface 523a, the 523b of lip part 523.

So, under the state of both ends of the surface 523a, the 523b of limit flange portion 523, if further carry out being pressed into of axial region 521, then as shown in figure 46, the upper-end surface 531b butt of the lower end surface 534a of patrix 534 and ca(u)lk mould 531.And if further make patrix 534 declines and push ca(u)lk mould 531 downwards, shown in Figure 47 amplifies, the engaging-in lip part 523 of the 531c of plastic working portion of ca(u)lk mould 531, thereby lip part 523 plastic deformation partly, and form the first protuberance 523d.The inner peripheral surface (internal face of the 523c of hole portion) that the first protuberance 523d forms than lip part 523 is more side-prominent to internal diameter, and this outstanding part is contained in the first accommodation section 521c that is provided with at axial region 521.Thus, the upper end of the 523c of hole portion (embedding area) of the lip part 523 after being pressed into fixing axial region 521 forms the first ca(u)lk portion 525.The corresponding load of the compress variation of this ca(u)lk processing and utilization and elastic member 536 applies to lip part 523 from first intermediate die 533, and continues to carry out under the restriction of lip part 523.

Stage after forming the first ca(u)lk portion 525 stops the decline of patrix 534, and after making each mould reset to initial point, takes out the one product of axial region 521 and lip part 523 from device.These one product are transported to the operation that forms the second ca(u)lk portion 526 in the lower end of the 523c of hole portion that is pressed into fixing axial region 521 back lip parts 523.The second ca(u)lk portion 526 by make lip part 523 partly plastic deformation form the second protuberance 523e (with reference to the enlarged view of Figure 41), and it be contained in the second accommodation section 521d that is provided with at axial region 521 and form.Though difference is slightly arranged, the formation order of the second ca(u)lk portion 526 is identical with the formation order of the first ca(u)lk portion 525, in this detailed.

And the second ca(u)lk portion 526 might not other operation after forming the first ca(u)lk portion 525 be provided with.For example, by improving above-mentioned device, also can form simultaneously with the first ca(u)lk portion 525.Certainly, from suppressing the viewpoint of manufacture cost, expectation forms two ca(u)lk portions 525,526 simultaneously.In addition, but also ring-type formation of above-mentioned first and second protuberance 523d, 523e, and also (circular-arc) forms intermittently.The shape of protuberance 523d, 523e fastening strength as requested etc. can suitably change.

As mentioned above, if under the state of both ends of the surface 523a, the 523b of limit flange portion 523, carry out ca(u)lk processing, can be at the surface accuracy of keeping both ends of the surface 523a, 523b, and keep the lip part 523 that is pressed into when finishing with respect to carrying out ca(u)lk under the state of the posture of axial region 521.Especially in the present embodiment, formation follows patrix 534 to descend and the structure that increases gradually to the load (restraint) of lip part 523, be pressed into the opposing increase so can effectively prevent from for example to follow the carrying out that is pressed into and cause producing between axial region 521 and the lip part 523 position deflection, or lip part 523 distortion.In addition, reach maximum in ca(u)lk process time limit system power, so if when being pressed under the situation of generation position deflection between axial region 521 and the lip part 523, also can utilize restraint to correct position deflection.

In addition, in the present embodiment, when being pressed into of axial region 521, also utilize the counterdie 532 and first intermediate die 533 to come limit flange portion 523, can be suitably to keep the state of axial region 521 and the relative posture of lip part 523, be pressed into axial region 521 in the time of the planeness etc. of perhaps correcting lip part 523.Therefore, axial region 521 improves with the assembly precision of lip part 523.

In addition, in said apparatus, constitute order, increase gradually and be subjected to axial clearance between the lower end surface 534a of patrix 534 of driving force (is the driving force that is used to move up and down at this) from driving mechanism with axial region 521, second intermediate die 535, ca(u)lk mould 531.According to described structure, descend by making patrix 534, can realize being pressed into of axial region 521, applying and ca(u)lk processing to the restraint of lip part 523.Therefore, driving mechanism is that single institution gets final product, cheapization of equipment cost.In addition, can implement to be pressed into a series of metal pattern 531～535 of mutual interlock, rectification, all operations of ca(u)lk, so realize the raising of productivity.

As previously discussed, after the assembly parts of making the lower end of lip part 523 being fixed in axial region 521, these assembly parts are transported to injection forming process.

(B) injection forming process

In the injection forming process, with axial region 521 and lip part 523 (assembly parts) as mosaic component, and with the radial bearing surface A of axial region 521 as benchmark, utilize melted material (being melting resin) to come injection moulding to constitute the covering part 524 of thrust parts 522 at this.Figure 48 A conceptually represents an example of injection forming process, but the metal pattern shown in this figure constitutes major component by the dynamic model 544 and the fixed die 545 of the ground arranged coaxial that can relatively move in the axial direction, and is formed and the corresponding chamber 547 of covering part 524 (thrust parts 522) shape To by two moulds 544,545.

But be provided with the cast gate 544a that injects and fill melted material P to chamber 547 at dynamic model 544.But in the end face of dynamic model 544, in the axial direction across chamber 547 and with the lower end surface 523b opposing end faces 544b of lip part 523 on, be provided with and the corresponding mould of the dynamic pressure groove shape portion 549 that should be arranged on the thrust shaft bearing surface C of thrust parts 522.

On fixed die 545, be provided with the accommodation section 545a that accommodates axial region 521.Among the upper-end surface 545b of fixed die 545, in the axial direction across chamber 547 and the position relative with the upper-end surface 523a of lip part 523, be provided with the thrust shaft bearing surface B that should be arranged on thrust parts 522 on the corresponding mould of dynamic pressure groove 522a1 shape portion 548.The knockout pin 546 that can relatively move in the axial direction with respect to fixed die 545 being provided with in interior week of fixed die 545, and utilize the upper-end surface 546a of knockout pin 546 to support the upper-end surface 521e of axial region 521.And Figure 48 A represents that knockout pin 546 is positioned at the state of origin position, and under this state, the upper-end surface 545b of fixed die 545 is than the short established amount of the axial dimension of axial region 521 with the axially spaced-apart distance setting of the upper-end surface 546a of knockout pin 546.Thereby, axial region 521 is being contained under the state of accommodation section 545a the upper-end surface 545b non-contact of lip part 523 and fixed die 545.

Become the formation that utilizes covering part 524 in the present embodiment and guarantee spindle unit 502 desired various precision, specifically, thrust parts 522 are with respect to the state of squareness and the parallelism between two thrust shaft bearing surface B, C of the thrust shaft bearing surface B of the radial bearing surface A of axial region 521.Therefore, upper-end surface 545b is with respect to the squareness of the internal face of the accommodation section 545a of fixed die 545, and two moulds 544, but 545 the lower end surface 544b that dashes the dynamic model 544 under the state of closing with respect to the parallelism of the upper-end surface 545b of fixed die 545 by retrofit for can satisfy the above-mentioned requirements precision.

Yet, because the thickness of covering part 524, follow the formation of above-mentioned ca(u)lk portion 525,526 and the protuberance M of the wall that forms at lip part 523 (hereinafter referred to as " protuberance M ".With reference to Figure 47.) and first and second protuberance 523d, 523e outstanding from the surface of covering part 524, have pair accuracy to shape in thrust bearing gap to cause the anxiety of harmful effect.Therefore, the axial dimension of chamber 547 is set at the axial dimension bigger than the width between the front end of two protuberance M.

In the metal pattern of said structure, at the accommodation section 545a that axial region 521 is inserted fixed dies 545 and after limiting radial bearing surface A, the A of axial region 521, but make dynamic model 544 near fixed die 545 matched moulds.After matched moulds is finished, in chamber 547, inject and fill melted material P (melting resin) via cast gate 544a, thus contour forming covering part 524.After the curing of melting resin is finished, carry out die sinking, when mentioning knockout pin 546, shown in Figure 48 B, be formed on the fixing lip part 523 in the lower end of axial region 521, and cover the covering part 524 on the full surface of lip part 523.Form thrust parts 522 thus, obtain spindle unit 502 as finished product.In addition, on the upper and lower end face of thrust parts 522 522a, 522b (surface of covering part 524), with the shaping of covering part 524 side by side contour forming thrust shaft bearing surface B, C (dynamic pressure groove).

And, as the melting resin of melted material P so long as injectable, no matter be the amorphism resin, or crystalline resin all can use.As spendable amorphous resin, for example can enumerate polysulfones (PSU), polyether sulfone (PES), Polyphenylene Sulfone (PPSU), Polyetherimide (PEI) etc., in addition as spendable crystalline resin, for example can enumerate liquid-crystalline polymer (LCP), polyether-ether-ketone (PEEK), polybutylene-terephthalate (PBT), polyphenylene sulfide (PPS) etc.Described base resin except that can using separately, also can mix two kinds with on use.In addition, in above-mentioned base resin also arbitrarily ratio cooperate and to give the various filling materials of various characteristics it.

And, as melted material P, except that above-mentioned resin, also can use metallic material, for example low melting metal such as magnesium alloy.In this case, covering part 524 is made of metal, and can improve the antifriction consumption of thrust parts 522.In addition, also can be shaped or CIM be shaped and forms covering part 524 by so-called MIM.

As shown above, in the present invention, axial region 521 and lip part 523 interfix by the acting in conjunction that is pressed into ca(u)lk, so realize the high strength of spindle unit 502.Especially in the present embodiment, by make lip part 523 partly plastic deformation form ca(u)lk portion 525,526, therefore can avoid causing the distortion of axial region 521 or lip part 523 integral body by ca(u)lk.Certainly, as long as the amount of deformation of the integral body of lip part 523 can be limited in small scope, also can make the whole plastic deformation of lip part 523.In addition, among the present invention, compare, can obtain firm stationary state with simple equipment, thereby the manufacture cost of spindle unit 502 is by cheapization with laser bonding.

In addition, the 523c of hole portion of axial region 521 bulged-in lip parts 523 is formed through hole,, realize the more high strength of spindle unit 502 so can form ca(u)lk portion 525,526 at the two ends of the 523c of hole portion.

In addition, because come the both ends of the surface (integral body of present embodiment flange portion 523) of coverage rate to the thrust bearing gap of lip part 523 by covering part 524, the precision in the thrust bearing gap that the protuberance M that forms so can avoid following the formation of ca(u)lk portion 525,526 and protuberance 523d, 523e cause worsens, in other words, can avoid the running accuracy of thrust direction is caused harmful effect.And then when the formation of covering part 524, guarantee spindle unit 502 necessary precision, particularly, thrust shaft bearing surface B, C are with respect to the squareness of the radial bearing surface A of axial region 521 and the parallelism between thrust shaft bearing surface B, C etc., so the making, axial region 521 that can relax lip part 523 to lip part 523 be pressed into and each operation of the formation of ca(u)lk portion 525,526 in require quality, can further realize cheapizationer of manufacture cost.

More than, the 5th mode of execution of the present invention is illustrated, but the present invention is not limited to the hydrodynamic bearing device 501 of structure shown in Figure 41.Below, based on the variation of the applicable hydrodynamic bearing device of the present invention of description of drawings.And in hydrodynamic bearing device shown below, the shared reference marker of structure mark to identical with the structure of above explanation only describes different structures.

Figure 49 represents first variation of hydrodynamic bearing device of the present invention.The main difference point of hydrodynamic bearing device shown in this figure and hydrodynamic bearing device shown in Figure 41 is: do not form thrust shaft bearing surface C on the downside end face 522b of the thrust parts 522 of spindle unit 502, this point between the downside end face 503a1 that second T52 of thrust bearing portion is arranged at the round plate 503a of the fixing dish hub 503 in the upper end of axial region 521 and the upside end face 507c of housing 507, and seal space S5 is arranged on the taper outer circumferential face 507d of housing 507 and coils this point between the inner peripheral surface 503b1 of cylindrical part 503b of hub 503.

Figure 50 represents second variation of hydrodynamic bearing device of the present invention.The main difference point of hydrodynamic bearing device shown in this figure and hydrodynamic bearing device shown in Figure 41 is: spindle unit 502 also possesses the second fixing lip part 527 of axial substantial middle portion at axial region 521, second T52 of thrust bearing portion is arranged at this point between the upside end face 508d of the lower end surface 527a of second lip part 527 and bearing sleeve 508, and the outer circumferential face 522c of thrust parts 522, and the inner peripheral surface 507a of the outer circumferential face 527c of second lip part 527 and housing 507 between this point of formation seal space S5.Even be described structure, for the one product of axial region 521 and the thrust parts 522 (lip part 523) that are provided with in the lower end of the axial region 521 also structure of applicable the invention described above.

More than, formed accommodation section 521c, the 521d that will be used to accommodate protuberance 523d, 523e and be arranged on the structure of axial region 521, but might not need accommodation section 521c, 521d are set, determine whether to consider necessary fastening strength etc. and be provided with and get final product.In addition, more than represented to pass through to lip part 523 enforcement plastic workings and with axial region 521 and the fixing situation of lip part 523 ca(u)lks, but also can be by axial region 521 being implemented plastic workings and both ca(u)lks being fixed.

In addition, more than, the 523c of hole portion of lip part 523 is formed through hole, and be formed with ca(u)lk portion 525,526, but shown in Figure 51, the 523c of hole portion is made as concavity at the two ends of the 523c of hole portion, only form ca(u)lk portion 525 and also can in the upper end portion of the 523c of hole portion.

In addition, more than, constitute thrust parts 522 by forming covering part 524 in the whole mode in surface that covers lip part 523, but it is whole that covering part 524 might not need to form the surface that covers lip part 523, also can be only in the surface of lip part 523 end face towards the thrust bearing gap form.Particularly, in hydrodynamic bearing device shown in Figure 41 501, form at both ends of the surface 523a, the 523b of lip part 523 and get final product, as in Figure 49 and the hydrodynamic bearing device 501 shown in Figure 50, only get final product in addition in the upper-end surface of lip part 523 523a formation.But, in hydrodynamic bearing device shown in Figure 50 501, because form seal space S5, so from improving the viewpoint of sealability, the outer circumferential face that is desirably in lip part 523 forms covering part 524 by the outer circumferential face of thrust parts 522.

In addition, the hydrodynamic bearing device that more than describes all forms discrete item with housing 507 and bearing sleeve 508, but for also applicable the present invention of hydrodynamic bearing device that both are integrated.In addition, in the hydrodynamic bearing device especially shown in Figure 41, also can be further that cover 509 or sealed member 510 is integrated with housing 507.

In addition, above illustration as the R51 of radial bearing portion, R52 and the T51 of thrust bearing portion, T52, utilize herringbone shape or spiral-shaped dynamic pressure groove to produce the structure of the dynamic pressure effect of lubricant oil, but as the R51 of radial bearing portion, R52, also can adopt so-called stepped bearing, many arc bearings or non-positive circular journal bearing, as the T51 of thrust bearing portion, T52, also can adopt so-called stepped bearing or waveform bearing.In addition, more than, illustration the structure of radial bearing portion is set at axial two positions, but also can be at an axial position or three radial bearing portion is set more than the position.

In addition, the situation that is made of the both sides of the R51 of radial bearing portion, R52 hydraulic bearing has been described more than, but also can have constituted a side or the both sides of the radial bearing R51 of portion, R52 by bearing in addition.For example omit diagram, but form round type, and the inner peripheral surface 508a of relative bearing sleeve 508 is formed the round type inner peripheral surface, also can constitute so-called positive circular journal bearing by radial bearing surface A with spindle unit 502.

Below, based on Figure 52～Figure 60 the 6th mode of execution of the present invention is described.At this, the 6th mode of execution relates to an example of the mode of execution of a second aspect of the present invention.

Figure 53 represents to possess the sectional drawing of spindle motor of the hydrodynamic bearing device 601 of the 6th mode of execution of the present invention.This spindle motor for example uses as the disk drive motor that possesses the HDD of disk, possesses: the supporting of non-contact diametrically is equipped with the hydrodynamic bearing device 601 of the spindle unit 602 of hub 603; For example by the drive portion 604 that constitutes across the relative stator coil 604a in the gap of radial direction and rotor magnet 604b; Carriage 605.Stator coil 604a is fixed in carriage 305, and rotor magnet 604b is fixed in hub 603.The housing 607 of hydrodynamic bearing device 601 is fixed in the interior week of carriage 605.In addition, as shown in the drawing, dish 606 (among Figure 53 being two) remain in hub 603.In the spindle motor that so constitutes, when when stator coil 604a switches on, make rotor magnet 604b rotation by the excitation power that produces between stator coil 604a and the rotor magnet 604b, and accompany therewith, remain in the dish 606 and the rotation of spindle unit 602 one of hub 603.

Figure 54 represents the sectional drawing of hydrodynamic bearing device 601.This hydrodynamic bearing device 601 possesses: by the spindle unit 602 of method manufacturing described later, and except that spindle unit 602, possess housing 607, be fixed in the cover 609, the sealed member 610 that sets in the other end opening side of housing of an end of bearing sleeve 608, the inaccessible housing 607 in the interior week of housing 607.

Housing 607 for example forms tubular by metallic material such as brass or resin material, and is the form with its axial both ends open.The outer circumferential face 608c of bearing sleeve 608 for example by bonding (comprise gap bonding and be pressed into bonding), be pressed into, deposited (comprising ultrasonic wave coating and laser cladding) wait the method that suits to be fixed on the inner peripheral surface 607a of housing 607.In addition, be formed with than the big footpath of inner peripheral surface 607a and be used for fixing the stationary plane 607b of cover 609 described later in the lower end side of inner peripheral surface 607a.

The porous plastid that bearing sleeve 608 for example is made of sintering metal forms cylindric.In this embodiment, bearing sleeve 608 is formed cylindric by the porous plastid that with copper is the sintering metal of primary coil, and is adhesively fixed in the inner peripheral surface 607a of housing 607.Bearing sleeve 608 also can be formed by the porous plastid that nonmetallic material such as resin or pottery constitute, in addition, except that porous plastids such as sintering metal, also can be by not with inner emptying aperture or have the material of structure that lubricant oil can't pass in and out the emptying aperture of degree size and form.

Be formed with in whole of the inner peripheral surface 608a of bearing sleeve 608 or a part of zone arranged a plurality of dynamic pressure grooves the zone as the radial dynamic pressure generating unit.In this embodiment, for example shown in Figure 55, a plurality of dynamic pressure groove 608a1 that the tilt angle is different mutually, the zone that 608a2 is arranged in the herringbone shape are formed on two positions in the axial direction separatedly.And, in this embodiment,, form on axle direction dynamic pressure groove 608a1, the 608a2 arrange regional of a side (is upside at this) asymmetric for circuit purpose with the lubricant oil that forms bearing inside wittingly.If describe in the illustrated mode of Figure 55, then the axial dimension X61 of the dynamic pressure groove 608a1 arrange regional of axial centre m6 upside (sealed member 610 sides) forms bigger than the axial dimension X62 of the dynamic pressure groove 608a2 arrange regional of downside.

For example shown in Figure 56,, be formed with in whole of the lower end surface of bearing sleeve 608 608b or a part of zone a plurality of dynamic pressure groove 608b1 are arranged in spiral-shaped zone as the thrust dynamic pressure generating section.This dynamic pressure groove 608b1 arrange regional is opposed with the upper-end surface 622a of the state of finished product and lip part described later 622, when spindle unit 602 rotations, and forms the thrust bearing gap (with reference to Figure 54) of first T61 of thrust bearing portion described later between the 622a of upper-end surface.

Be formed with to axially extended a plurality of axial groove 608c1 at the outer circumferential face 608c of bearing sleeve 608.These axial grooves 608c1 functions as follows: main when the use of hydrodynamic bearing device 601, the situation of the mistake quantity not sufficient of generation lubricant oil is inferior in bearing interior space, is used for will being somebody's turn to do as soon as possible the recovering state of quantity not sufficient to suitable state.

The cover 609 of the lower end side obturation of housing 607 is for example formed by metallic material or resin material, and be fixed in the stationary plane 607b that is provided with in interior all lower ends of housing 607.At this moment, cover 609 fixing can use bonding, be pressed into, arbitrary method such as deposited, welding.

Be formed with the dynamic pressure groove arrange regional of the arrangement mode (direction of spiral is opposite) that for example is same with Figure 56 in whole of the upper-end surface of cover 609 609a or a part of zone.This dynamic pressure groove arrange regional (thrust dynamic pressure generating section) is opposed with the lower end surface 622b of the state of finished product and lip part 622, when the rotation of spindle unit 602, and lower end surface 622b between form the thrust bearing gap (with reference to Figure 54) of second T62 of thrust bearing portion described later.

In the present embodiment, form independently by metallic material or resin material and housing 607 as the sealed member 610 of sealing mechanism, and by be pressed into, week in the upper end that arbitrary method such as bonding, deposited, welding is fixed in housing 607.

Sealing surface 610a in that being formed with in interior week of sealed member 610 is taper forms seal space S6 between the outer circumferential face of sealing face 610a and axial region described later 621.Lubricant oil is full of under the state of hydrodynamic bearing device 601 inside, and the pasta of lubricant oil is always maintained in the scope of seal space S6.

Spindle unit 602 has been fixed the lower end of axial region 621 by axial region 321, in the hole that is arranged at central authorities the lip part 622 of ring-type constitutes.In this embodiment, shown in Figure 54, be formed with radial bearing surface 621a in the periphery of axial region 621, this radial bearing surface 621a dynamic pressure groove 608a1,608a2 arrange regional with the inner peripheral surface 608a that is arranged at bearing sleeve 608 diametrically is relative.In this embodiment, radial bearing surface 621a is arranged at two places in the axial direction separatedly, is provided with the diameter specific diameter to the little withdrawing slot part 621b of bearing surface 621a between described radial bearing surface 621a, 621a.

The lower end of axial region 621 is pressed into lip part 622.In addition, the axial end portion (is bearing sleeve 608 sides at this) in axial region 621 and the chimeric zone of lip part 622 is formed with the ca(u)lk fixing part 623 with lip part 622 ca(u)lks.

And, preferably form for axial region 621 by excellent material such as stainless steel equal strength, rigidity, antifriction consumptions, in addition, compare the plastic working excellent material formation that ca(u)lk adds man-hour with axial region 621 for lip part 622 preferences such as brass etc.

Assembled after the above-mentioned structure member,, thereby obtained hydrodynamic bearing device 601 as finished product to bearing interior space (zone of representing with the some apperance of loosing among Figure 54) packing lubrication oil.At this, can use various lubricant oil as the lubricant oil that is full of in hydrodynamic bearing device 601 inside, but when the lubricant oil that offers the Hydrodynamic bearing apparatus that disk drive device such as HDD uses considers that it uses or the temperature variation in when conveying, suitable to use low relative evaporation and the good ester of low viscosity be lubricant oil, for example dioctyl sebacate (DOS), dioctyl azelate (DOZ) etc.

In the hydrodynamic bearing device 601 of said structure, when spindle unit 602 rotation, the dynamic pressure groove 608a1 of the both sides of bearing sleeve 608,608a2 arrange regional are across the radial bearing gap and relative with radial bearing surface 621a, the 621a of axial region 621.And, follow the rotation of spindle unit 602, even in up and down any dynamic pressure groove 608a1,608a2 arrange regional, lubricant oil is pressed into towards the axial centre m6 of dynamic pressure groove 608a1,608a2, its pressure rises.Utilize the dynamic pressure effect of this kind dynamic pressure groove 608a1,608a2, rotating freely diametrically, first R61 of radial bearing portion and second R62 of radial bearing portion of non-contact supporting shaft part 602 are formed on two positions respectively in the axial direction separatedly.

Meanwhile, in the thrust bearing gap between the upper-end surface 422a of dynamic pressure groove 608b1 arrange regional that is provided with on the 608b of the lower end surface of bearing sleeve 608 and relative therewith lip part 622 and the thrust bearing gap between the lower end surface 422b of dynamic pressure groove arrange regional that is provided with on the 409a of the upper-end surface of cover 409 and relative therewith lip part 422, utilize the dynamic pressure effect of dynamic pressure groove to form the oil film of lubricant oil respectively.And, utilize the pressure of these oil films, be formed in first T41 of thrust bearing portion and second T42 of thrust bearing portion of non-contact supporting shaft part 402 on the thrust direction respectively.

Below, an example of the manufacture method of spindle unit 602 is described.

Figure 52 represents the example of flow chart of manufacture method of the shaft member for fluid bearing device 602 of present embodiment.Shown in Figure 52, this manufacture method comprises: accept relevant assembled components, i.e. the operation S101 of axial region 621 and lip part 622; With group (lot) the operation S102 that be unit mate the axial region 621 and the lip part 622 of acceptance; The operation S103 of difference axial region 621 of arbitrary extracting and lip part 622 the axial region 621 after mating and the group of lip part 622; The operation S104 that the internal diameter size in the hole of the outside dimension of the axial region 621 that extracts and lip part 622 is measured; Poor based on each size of measuring estimated the operation S105 of the magnitude of interference (amount of being pressed into) when being pressed into two parts; The axial region 621 that will carry out the evaluation of magnitude of interference is pressed into the operation S106 in the hole of lip part 622; Whether the magnitude of interference after estimating is lower than the operation S107 that the specified value of predefined magnitude of interference is judged; The product that are pressed into that the result who is judged to be judgement are lower than specified value are implemented ca(u)lk processing.Below, S102 is that the center illustrates each operation S101～S108 with the coupling operation.

At first, in operation S101, the axial region 621 that will obtain through various manufacturing procedures and lip part 622 are that unit receives assembling procedure respectively with the group.At this, as axial region 621, accept after the dumming such as for example turning, the outer circumferential face (the radial bearing surface 621a shown in Figure 54,621a) that comprises radial bearing surface is implemented abrasive machining, thereby the outer circumferential face retrofit that should be pressed into is to the axial region of highi degree of accuracy (number μ M are following).In contrast, as lip part 622, accept with the different processing of the both ends of the surface that become the thrust shaft bearing surface (upper-end surface 622a shown in Figure 54 and lower end surface 622b), for example roughing of turning etc. and the hole lip part that forms inner peripheral surface 622c simultaneously.

Next, to being that axial region 621 and the lip part 622 that unit accepts mates (operation S102) with the group.Specifically, shown in Figure 57, so that each is organized L _SThe representative outside dimension M of the axial region of determining 621 _S, with each L on the same group mutually _fThe representative internal diameter size M in the hole of the lip part of determining 622 _F1Difference P _M1Desired value P less than magnitude of interference _AimMode mate.At this,, promptly represent internal diameter size M with the address size of inner peripheral surface 622c _F1(will represent size M with the coupling shown in Figure 60 _S, M _fDifference as desired value P _AimCoupling) employed group of L _fRepresentative internal diameter size M _fCompare the group L of big lip part 622 _fGroup L with axial region 621 _SMate.

And, as the desired value P of magnitude of interference _Aim, the anti-avulsion power of the minimum that can obtain requiring according to the lift-launch machine of its purposes or hydrodynamic bearing device 601 etc., and in the scope that does not produce by the upper limit that is pressed into the low degree that causes the parts precision, set aptly.In addition, the scope of determining this moment becomes the allowed band of suitable magnitude of interference (among Figure 57, by regional A ₀The scope of expression).In addition, from the difference of above-mentioned processing method, the group L of axial region 621 _SMachining tolerance T _SGroup L than lip part 622 _fMachining tolerance T _fLittler.In addition, in this embodiment, as the group L of axial region 621 with lip part 622 _S, L _f, use and represent outside dimension M _SReach and represent internal diameter size M _F1Equal parts that equate with the mean outside diameter size and the mean inside diameter size of each group.

The group L of the axial region 621 after mate as described above _SGroup L with lip part 622 _f, at random select and extract an axial region 621 and lip part 622 (operation S103) respectively.And, the internal diameter size (operation S104) in the outside dimension of the one group of axial region 621 that measure to extract respectively and the hole of lip part 622.

Based on the size of each parts of measuring in operation S104, the magnitude of interference that obtains during to being pressed into of both sides' parts is estimated.Specifically, from the information of the size of relevant each parts of being stored in suitable storage (comprising database), calculate the value of the diameter dimension difference of one group of axial region 621 being used to be pressed into and lip part 622 as magnitude of interference.That calculates transmits to the judgement operation S107 as the magnitude of interference of back operation (below operation) about the information of magnitude of interference.

The axial region 621 that finishes the mensuration of size is pressed into the hole (operation S106) of the lip part paired 622 with it.At this, the magnitude of interference that obtains is the value of being calculated by operation S105, so the magnitude of interference of the fashionable reality of accident level pressure, and in the judgement operation S107 of the magnitude of interference of next operation, whether judgement needs ca(u)lk processing (operation S107) separately.Specifically, be lower than at the magnitude of interference of estimating under the situation of pre-set threshold (value of the magnitude of interference suitable), this be pressed into product carry out ca(u)lk processing (operation S108) with the anti-avulsion power that is considered to the bottom line needs.At this,, carry out the setting of its ca(u)lk condition to apply the mode of ca(u)lk power without exception to being judged to be all product that are pressed into that need ca(u)lk processing.

In addition, in operation S107,,, and finish its assembling as finished product without ca(u)lk processing for being judged to be the product that are pressed into that do not need ca(u)lk processing.

At this, ca(u)lk processing is implemented local plastic working and is carried out any of axial region 621 and lip part 622 under the axial region 621 and lip part 622 state that keep with suitable anchor clamps by being pressed into after integrated.At this moment, processing object is for comparing the lip part 622 that can be formed by more soft material with axial region 621, at this moment, by to the upper-end surface 622a that is pressed near the lip part 622 the engagement portion of axial region 621 in push suitable ca(u)lk processing usefulness week anchor clamps make lip part 622 plastic deformations.In addition, in order to reduce the distortion of the lip part 622 that is produced by ca(u)lk, especially added the protuberance of the periphery generation of the Ministry of worker by ca(u)lk, remove the part in the interior week of upper-end surface 622a of lip part 622, perhaps the part of the upper-end surface 622a side of inner peripheral surface 622c is also effective.

Through above operation S103～S107 (as required to operation S108), one group of axial region 621 and lip part 622 are implemented to be pressed into and to implement as required ca(u)lk processing, form spindle unit 602 as assembling part.With described a series of operation S103～S108 to the group L _S, L _fIn all as far as possible axial region 621 and lip part 622 implement, and obtain spindle unit 602 as assembling part.

So,, realize the assembling of axial region 621 and lip part 622 by being pressed into, and, estimate the magnitude of interference when being pressed into, and set the ca(u)lk condition based on the magnitude of interference after estimating, thus can be according to the size adjustment ca(u)lk condition of the magnitude of interference of estimating.Therefore, remedy the inequality of magnitude of interference by ca(u)lk, and stable retention force can be applied between axial region 621 and the lip part 622.Specifically, be lower than at the magnitude of interference of estimating under the situation of allowed band of suitable magnitude of interference, with regard to Figure 57, at regional A ₁The situation of lip part 622 and axial region 621 combinations under, based on the value of the magnitude of interference of estimating, implement ca(u)lk processing with suitable ca(u)lk condition, can essence and enhancing that ca(u)lk is formed play a role.

In addition, in this mode of execution, before being pressed into operation, carrying out and will each be organized L with the group unit _S, L _fThe representative outside dimension M of the axial region of determining 621 _SRepresentative internal diameter size M with the hole of lip part 622 _fDifference P _M1Be set at desired value P than magnitude of interference _AimLittle coupling.Therefore, the allowed band of suitable magnitude of interference is (among Figure 57, by regional A ₀The scope of expression.At this, with the machining tolerance T of axial region _SConsistent.) on the whole to the big side shifting of interference quantitative change.Its result is as the too small relatively regional A of magnitude of interference ₁(magnitude of interference is from the allowed band zone A of suitable magnitude of interference ₀To diminish lateral deviation from scope) increase, but therefore magnitude of interference becomes excessive relatively regional A ₂(magnitude of interference is from the allowed band zone A of suitable magnitude of interference ₀To become big lateral deviation from scope) reduce.At this, the relevant zonule A excessively that belongs to magnitude of interference ₁Lip part 622 and the assembling part of the combination of axial region 621, carry out ca(u)lk processing based on the magnitude of interference of estimating, can adjust its retention force, therefore guarantee to be pressed into for workpiece as much as possible in the group and ca(u)lk after retention force, and subdue the ratio of the excessive assembly failure product that cause of magnitude of interference, and can improve yield rate.

In addition, as mentioned above with under the group unit situation of mating, for example shown in Figure 58, also can carry out will be to each group L _S, L _fThe minimum outer diameter size M of the axial region of determining 621 _SminMinimum diameter size M with the hole of lip part 622 _FminDifference as the desired value P of magnitude of interference _AimCoupling.By after so mating, being pressed into, can getting rid of and be included in the regional A that magnitude of interference becomes excessive relatively ₂In the assembling part of lip part 622 and axial region 621.Thereby, further subdue by the assembly failure that is pressed into generation, can further improve yield rate as spindle unit 602.And, as Figure 58 illustration, represent outside dimension M _SWith minimum outer diameter size M _SminDifference and machining tolerance T _SHalf corresponding to group of L _SSituation under (for the group L of lip part _fToo, represent internal diameter size M _F2With minimum diameter size M _FminDifference and machining tolerance T _fHalf corresponding to situation under), can represent size M by each _S, M _F2Between poor P _M2Mate, management becomes easy.

In addition, as this mode of execution, be lower than the product that are pressed into of the combination of established amount for the magnitude of interference of estimating, if giving certain ca(u)lk condition sets, then the control of ca(u)lk processing also becomes easy.In addition, not only the mode of ca(u)lk processing also can be oversimplified its equipment, and economic aspect is suitable.

More than, the manufacture method of the spindle unit 602 of the 6th mode of execution of the present invention is illustrated, certainly, in the scope of the present invention in, also variable its mode of execution.

For example in the above-described embodiment, the situation of carrying out the evaluation (operation S105) of magnitude of interference based on the result that the internal diameter size in the hole of the outside dimension of axial region 621 and lip part 622 is measured has been described, but also can have carried out the evaluation of magnitude of interference based on information in addition.Figure 59 represents the flow chart of the manufacture method of such example, mainly has this point of following operation, its structure (operation) is different with the manufacture method shown in Figure 52, that is: the operation S106-1 that begins to be pressed into after extracting the operation S103 of the axial region 621 that should be pressed into and lip part 622; The operation S106-2 of the load when measurement is pressed into; Reach the operation S106-3 that estimates magnitude of interference based on the load of measuring.

So, if measure the load when being pressed into and estimate magnitude of interference based on the load of measuring, then correspondingly can access and be pressed into the relevant information of state with it with the independent product that are pressed into, therefore can based on reflection separately the information of the concrete state that is pressed into estimate magnitude of interference (inferring the retention force that obtains by being pressed into).In addition, the pressure transducer of the load sensor that utilization is provided with on the anchor clamps that ca(u)lk is used etc. is that axial region 621 is measured from the reaction force that lip part 622 is subjected to being pressed into masterpiece, compares with the situation of independent size up before being pressed into, can oversimplify its process number and equipment, be fit to.Certainly, as long as load (counter-force etc.) former state of measuring can be used in the judgement operation S107 of back as the magnitude of interference of estimating, also the determinating reference among the operation S107 can be replaced into the ca(u)lk load and judge.

In addition, in the above mode of execution, the situation that following operation is set is described, that is: as with according to purposes or carry the threshold value (lower limit) that the suitable value of the anti-avulsion power of desired minimums such as machine is set magnitude of interference, and in fact be lower than under the situation of threshold value at the magnitude of interference of estimating, set operation (operation S107) situation of ca(u)lk condition without exception, but also can suitably set the ca(u)lk condition certainly by method in addition.For example, in the evaluation (operation S105 or operation S106-3) of magnitude of interference afterwards, also can replace operation S107, with the fastening force that forms based on the magnitude of interference of estimating with by the summation that ca(u)lk forms fastening force is constant mode, set the operation (afterwards, implementing ca(u)lk processing) of ca(u)lk condition according to the ca(u)lk condition of setting.Perhaps, do not satisfy the magnitude of interference of aforesaid threshold value, can set the operation of its ca(u)lk condition yet with aforesaid threshold value by the summation mode consistent of the fastening force that is pressed into generation with the fastening force that produces by ca(u)lk for the magnitude of interference of estimating.By setting ca(u)lk condition like this, can access uneven further minimizing, and have the spindle unit of uniform constant intensity.

And the judgement operation S107 of that adopt, magnitude of interference in the above-described embodiment evaluation (operation S105 and operation S106-3) and magnitude of interference might not be to organize the coupling operation S102 that unit carries out.That is,,, also can control to comprise whether needing the ca(u)lk of ca(u)lk condition through above-mentioned operation even without group unit and accepting under the situation of each parts with all product states of sneaking into, therefore can to spindle unit give uneven still less and stable constant intensity.

In addition, in this embodiment, illustration ca(u)lk fixing part 623 is arranged on the situation of axial region 621 and the upper axial end (upper-end surface 622a side) of the embedding area of lip part 622, but also can utilize suitable anchor clamps that the lower end surface 622b of lip part 622 implemented ca(u)lk processing interior week in addition.In this case, in judging operation S107,, determine the ca(u)lk processing of side at one end, perhaps whether need the ca(u)lk (setting the ca(u)lk condition) of both end sides to get final product according to the anti-avulsion power of necessity.

More than Shuo Ming manufacture method of the present invention is not limited to above-mentioned structure, also applicable to the hydrodynamic bearing device of the structure with other.

In for example above-mentioned mode of execution, outer circumferential face with axial region 621 has been described as radial bearing surface 621a, and the situation that the upper-end surface 622a and the lower end surface 622b of lip part 622 used as the thrust shaft bearing surface respectively, but be not limited thereto.For example omit diagram, for the also applicable the present invention of spindle unit who only upper-end surface 622a among both sides' end face 622a, the 622b is used as the hydrodynamic bearing device of the structure of thrust shaft bearing surface use.

And, in the above embodiment, housing 607 and bearing sleeve 608 are provided with independently, but the parts more than 2 integrated each other (form by same material, perhaps embed a side parts and contour forming the opposing party's parts) that also can be in the scope that can assemble will from the parts group of the fixed side that constitutes described hydrodynamic bearing device 601, select.For example in the structure shown in Figure 54, can be integrated between housing 607 and bearing sleeve 608, housing 607 and cover 609, housing 607 and the sealed member 610.Also can with housing 607 and bearing sleeve 608, and sealed member 610 integrated.In addition, the shape with the incorporate lip part of axial region can not hinder of the present invention being suitable for yet.For example, has the spindle unit that the lip part of sealing surface is set in periphery, also applicable the present invention for one.

In addition, in above mode of execution (first to the 6th mode of execution), as the R11 of radial bearing portion, R12, R21, R22, R31, R32, R41, R42, R51, R52, R61, R62 and the T11 of thrust bearing portion, T12, T21, T22, T31, T32, T41, T42, T51, T52, T61, T62 illustration utilize herringbone shape or spiral-shaped dynamic pressure groove to produce the structure of the dynamic pressure effect of lubricant oil, but the present invention is not limited thereto.

For example, as the R11 of radial bearing portion, R12, omit diagram, but also can adopt the so-called stair-stepping dynamic pressure generating unit that axial groove is formed on a plurality of positions of circumferencial direction, perhaps, arrange a plurality of arc surfaces in a circumferential direction, and between the outer circumferential face (radial bearing surface 21a) of relative axial region 21, form so-called many arc bearings in the radial direction gap (bearing play) of wedge-like.Certainly, the R21 of radial bearing portion, R22, R31, R32, R41, R42, R51, R52, R61, the R62 of mode of execution (second～the 6th mode of execution) about other also can adopt same structure.

Perhaps, also the inner peripheral surface 8a that becomes the bearing sleeve 8 of radial bearing surface can be formed the round type inner peripheral surface of the dynamic pressure groove that is not provided as the dynamic pressure generating unit or arc surface etc., and the outer circumferential face (radial bearing surface 21a) by the round type relative with this inner peripheral surface, constitute so-called positive circular journal bearing.Certainly, the R21 of radial bearing portion, R22, R31, R32, R41, R42, R51, R52, R61, the R62 of mode of execution (second～the 6th mode of execution) about other also can adopt same structure.

In addition, the radial bearing portion of above explanation also can only be arranged on a position except that being arranged at separatedly in the axial direction two positions as described, perhaps, and also can be in the axial direction from being provided with three every ground more than the position.

In addition, the side of the T11 of thrust bearing portion, T12 or both sides omit diagram equally in first mode of execution, but in the zone that becomes the thrust shaft bearing surface, also can be by with predetermined distance the so-called stepped bearing of the dynamic pressure groove of a plurality of radial direction groove shape being set at circumferencial direction, perhaps waveform bearing (end face is for being in harmonious proportion the bearing of waveform of waveform etc.) waits and constitutes.Certainly, the T21 of thrust bearing portion, T22, T31, T32, T41, T42, T51, T52, T61, the T62 of mode of execution (second～the 6th mode of execution) about other also can adopt same structure.

In addition, in the above description, illustrated the dynamic pressure generating unit all has been arranged on fixed side (housing 57,157,377,457,507 or bearing sleeve 8,108,308,408,508,608, cover 9,109,309,409,509,609 etc.) situation, but also can be arranged on rotary side (axial region 21,121,321,421,521,621 or lip part 22,122,322,422,622 (comprising thrust parts 522,527), hub 53,153,373,453,503 etc.) with its part or all.For example, if refer to first mode of execution, also can be at the outer circumferential face (radial bearing surface 21a) of axial region 21 or both ends of the surface 22a, the 22b of lip part 22, and among the lower end surface 53a1 of hub 53 one is provided with described dynamic pressure generating unit more than the position.

In addition, the 3rd mode of execution for example, also can carry out under being pressed into of axial region 321 or the ca(u)lk fixation case with the state that has limited lip part 322, at the lower end surface 331b of illustrated first anchor clamps 331 of Figure 28 A～Figure 28 C and the upper-end surface 332a of second anchor clamps 332, set in advance and the corresponding mould of thrust dynamic pressure generating unit, also can apply corrective force, and form and the corresponding dynamic pressure generating unit of mould at both ends of the surface 322a, the 322b of lip part 322 to lip part 322.

In addition, in the above description, spindle unit 2 rotation has been described, and has supported its structure, but in contrast by non-contacts such as bearing sleeves 8, for bearing sleeve 8 sideway swivels, and by its also applicable the present invention of structure of spindle unit 2 side bearings.In this case, for example for first mode of execution, bearing sleeve 8 constitutes one or is fixed in hub 3,53 separately, and rotates with hub 3,53 one.Certainly, said structure is not limited to first mode of execution, can adopt too for the hydrodynamic bearing device 101,151,301,371,401,451,501,601 of second～the 6th mode of execution.

In addition, in the above explanation, as the inside that is used to be filled to hydrodynamic bearing device 1,51,101,151,301,371,401,451,501,601, and form in radial bearing gap and thrust bearing gap fluid film the fluid illustration lubricant oil, but also can use the fluid that can form fluid film in addition, for example gas such as air, or magnetic fluid etc. has mobile oiling agent, perhaps lubricating grease etc.

Claims (34)

1, a kind of shaft member for fluid bearing device, the lip part that it possesses axial region and is fixed in an end of axial region, and

Between the outer circumferential face of axial region and the face relative, form the radial bearing gap with this outer circumferential face, and between the end face of lip part and the face relative, form the thrust bearing gap with this end face, and by between the radial bearing gap and the film of the fluid that forms of thrust bearing gap come the described shaft member for fluid bearing device of swivel bearing, described shaft member for fluid bearing device is characterised in that

Axial region is pressed into the hole portion that is arranged at lip part, and a side of axial region and lip part partly is subjected to plastic working and ca(u)lk is fixed in the opposing party.

2. shaft member for fluid bearing device according to claim 1 is characterized in that,

By more being implemented plastic working by the zone of internal side diameter to the zone in thrust bearing gap, the specific surface of lip part obtains ca(u)lk portion.

3. shaft member for fluid bearing device according to claim 2 is characterized in that,

Be provided with the portion of overflowing at axial region, the described portion of overflowing is used to make the plastic deformation of the lip part that is produced by plastic working to overflow to internal side diameter.

4. shaft member for fluid bearing device according to claim 1 is characterized in that,

Week is provided with the portion of overflowing in an end face of lip part, and this portion of overflowing is implemented ca(u)lk processing.

5. shaft member for fluid bearing device according to claim 4 is characterized in that,

Implement ca(u)lk processing in the position that the external diameter end from the portion of overflowing leaves.

6. shaft member for fluid bearing device according to claim 4 is characterized in that,

First ridge that outside diameter produced by the part of depression being subjected to ca(u)lk processing constitutes the thrust shaft bearing surface.

7. shaft member for fluid bearing device according to claim 4 is characterized in that,

Forms and the ca(u)lk portion of axial region ca(u)lk by second ridge that internal side diameter produced of the part of depression being subjected to ca(u)lk processing.

8. shaft member for fluid bearing device according to claim 4 is characterized in that,

First ridge is below the 3 μ m from the outstanding height of thrust shaft bearing surface.

9. shaft member for fluid bearing device according to claim 1 is characterized in that,

Between the outer circumferential face of the inner peripheral surface of the hole of lip part portion and axial region, be provided with: be pressed into the fixing part of fixing part, ca(u)lk, absorb the part of the plastic deformation of following ca(u)lk.

10. shaft member for fluid bearing device according to claim 9 is characterized in that,

The absorption portion of plastic deformation forms by being filled in the gap that is provided with between lip part and the axial region.

11. shaft member for fluid bearing device according to claim 9 is characterized in that,

The radial direction inboard of the part of depression is formed with the absorption portion of plastic deformation being subjected to ca(u)lk processing.

12. shaft member for fluid bearing device according to claim 9 is characterized in that,

The absorption portion of ca(u)lk fixing part and plastic deformation is formed on the same area.

13. shaft member for fluid bearing device according to claim 9 is characterized in that,

In the end face of a side of lip part, week be provided with the portion of overflowing, and this portion of overflowing is implemented ca(u)lk processing.

14. shaft member for fluid bearing device according to claim 1 is characterized in that,

The end face and then the lining cap in the face of the thrust bearing gap of lip part cover.

15. shaft member for fluid bearing device according to claim 14 is characterized in that,

Covering part is inlayed axial region and lip part and contour forming.

16. shaft member for fluid bearing device according to claim 14 is characterized in that,

Be provided with the thrust dynamic pressure generating section that makes the thrust bearing gap produce hydrodynamic in covering part.

17. shaft member for fluid bearing device according to claim 1 is characterized in that,

Hole portion is the through hole at the both ends of the surface opening of lip part.

18. a hydrodynamic bearing device is characterized in that,

Possesses each described spindle unit in the claim 1～17.

19. a motor is characterized in that,

Possesses the described hydrodynamic bearing device of claim 18.

20. the manufacture method of a shaft member for fluid bearing device, described shaft member for fluid bearing device possesses axial region and is fixed in the lip part of an end of axial region, and between the outer circumferential face of axial region and the face relative, form the radial bearing gap with this outer circumferential face, and between the end face of lip part and the face relative, form the thrust bearing gap with this end face, and by between the radial bearing gap and the film of the fluid that forms of thrust bearing gap come the described shaft member for fluid bearing device of swivel bearing, the manufacture method of described shaft member for fluid bearing device is characterised in that, comprising:

Axial region is pressed into the operation of the hole portion of lip part setting;

Axial region or lip part are carried out the operation of ca(u)lk.

21. manufacture method according to claim 20 is characterized in that,

At least under the state of the end faces of both sides of limit flange portion, carry out the ca(u)lk operation.

22. manufacture method according to claim 20 is characterized in that,

Set ca(u)lk power according to the power of being pressed into.

23. manufacture method according to claim 20 is characterized in that,

Axial region is pressed into the hole portion of the lip part with large-diameter portion, forms the gap between large-diameter portion and axial region, and all sides are implemented ca(u)lk processing in the end face to lip part, at least a portion in gap is filled in the distortion that is produced by ca(u)lk processing.

24. manufacture method according to claim 23 is characterized in that,

Constitute large-diameter portion by tubular face, and implement ca(u)lk processing with the state that between the outer circumferential face of this tubular face and axial region, forms the gap than the bigger footpath of the portion that is pressed into of hole portion.

25. manufacture method according to claim 23 is characterized in that,

Undercut groove by ring-type constitutes large-diameter portion, and implements ca(u)lk processing with the state that forms the gap between the outer circumferential face of this undercut groove and axial region.

26. manufacture method according to claim 20 is characterized in that,

After process is pressed into operation and ca(u)lk operation, in the end face formation covering part in the face of the thrust bearing gap of lip part.

27. the manufacture method of a shaft member for fluid bearing device, described shaft member for fluid bearing device possesses: outer circumferential face is faced the lip part in thrust bearing gap in the face of the end face of axial region, an end that is fixed in axial region and at least one side in radial bearing gap, the manufacture method of described shaft member for fluid bearing device is characterised in that, comprising:

Axial region is pressed into the operation of the hole portion of lip part setting;

The operation that magnitude of interference during to being pressed into of axial region and lip part is estimated;

Based on the magnitude of interference after estimating, set the operation of the ca(u)lk condition after being pressed into.

28. manufacture method according to claim 27 is characterized in that,

Optional one group of axial region and lip part from axial region and lip part group separately are pressed into operation, and

Before being pressed into operation, the representative outside dimension that carries out the axial region that will determine each group with the group unit is set at the coupling littler than the desired value of magnitude of interference with the difference of the representative internal diameter size of the hole portion of lip part.

29. manufacture method according to claim 28 is characterized in that,

The difference of minimum diameter size of carrying out the hole portion of the minimum outer diameter size of the axial region that will determine each group and lip part with the group unit is set at the coupling of the desired value of magnitude of interference.

30. according to claim 27 or 28 described manufacture methodes, it is characterized in that,

Internal diameter size based on the hole portion of the outside dimension of the axial region of measuring before being pressed into and lip part carries out the evaluation of magnitude of interference.

31. according to claim 27 or 28 described manufacture methodes, it is characterized in that,

Load when being pressed into carries out the evaluation of magnitude of interference.

32. according to claim 27 or 28 described manufacture methodes, it is characterized in that,

The lower limit of the magnitude of interference that setting should be estimated is lower than under the situation of this lower limit at the magnitude of interference of estimating, and is constant value with the ca(u)lk condition enactment, and carries out ca(u)lk processing.

33. according to claim 27 or 28 described manufacture methodes, it is characterized in that,

Set the ca(u)lk condition, it is constant making the summation based on the magnitude of interference of estimating and the magnitude of interference that is formed by ca(u)lk.

34. the manufacture method of a hydrodynamic bearing device is characterized in that,

To carry out the assembling of hydrodynamic bearing device by the spindle unit of claim 20 or 27 described method manufacturings as component parts.

Images