CN100356074C - Hydrodynamic bearing device - Google Patents
Hydrodynamic bearing device Download PDFInfo
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- CN100356074C CN100356074C CNB2005100885237A CN200510088523A CN100356074C CN 100356074 C CN100356074 C CN 100356074C CN B2005100885237 A CNB2005100885237 A CN B2005100885237A CN 200510088523 A CN200510088523 A CN 200510088523A CN 100356074 C CN100356074 C CN 100356074C
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Abstract
A hydrodynamic bearing device in which an introducing minimum clearance for causing capillary phenomenon is formed from the location in the proximity of the opening of a communicating path to the open end of the bearing hole in between the cover and the end face on the open end of the sleeve so that the operating fluid from the communicating path in the sleeve flows into the bearing hole by the capillary phenomenon; a vent hole leading to the outside air is formed on the cover; a fluid storage space for storing the operating fluid is formed on the inside surface of the cover or the end face on the open end of the sleeve to communicate the introducing minimum clearance and the vent hole in the circumferential direction; and the air bubbles separated at the fluid storage space are exhausted outward from the vent hole.
Description
Technical field
The present invention relates to rotate the middle hydrodynamic bearing devices that use such as spindle drive motor that drive disk, CD etc.
Background technique
As the bearing means that uses in the spindle drive motor of hard disk unit etc., adopt the situation of the hydrodynamic bearing device better to increase gradually, to replace the ball bearing unit that used in the past than ball bearing running accuracy height and bass.
As this hydrodynamic bearing device, the hydrodynamic bearing device that discloses in the Japanese patent laid-open 11-82486 communique is for example arranged.This hydrodynamic bearing device has as shown in figure 18: axle 51; 51 leave the axle sleeve 52 that is configured in periphery with gap with this; Be arranged on axle 51 two end part and leave the large diameter thrust flange 53,54 of the posture configuration in gap, be full of the working fluid that constitutes by lubricant oil in the gap between the both ends of the surface of the gap between the outer circumferential face of axle 51 and the inner peripheral surface of axle sleeve 52 and the face (upper surface of the lower surface of thrust flange 53 and thrust flange 54) of thrust flange 53,54 inboards and the axle sleeve 52 relative with it with both ends of the surface with respect to axle sleeve 52.Outer circumferential face at axle 51 forms dynamic pressure groove 56, constituted and made spools 51 by the outer motor rotary driving force of figure etc. during with axle sleeve 52 relative rotations, the pressure of the working fluid that utilization is assembled by this dynamic pressure groove 56, make axle 51 and axle sleeve 52 diametrically intermediary specified gap and the supported freely radial fluid bearing of rotation are arranged.In addition, on the inner side surface of thrust flange 53,54, form dynamic pressure groove 57,58, constituted when utilizing described rotary driving force etc. to make to be installed in thrust flange 53,54 on the axle 51 with axle sleeve 52 relative rotations, utilization is by the pressure of the working fluid of these dynamic pressure groove 57,58 gatherings, and making axle 51 and axle sleeve 52 go up intermediary in thrust direction (axially) has specified gap and the supported freely thrust FDB of rotation.
In this hydrodynamic bearing device, inner peripheral surface in axle sleeve 52 and the intermediate portion between the outer circumferential face are the center with the axle center, every suitable angle (for example 180 degree), form a plurality of communication channels 59 that extend with axis parallel ground.By these communication channels 59, the space between the both ends of the surface of the face of thrust flange 53,54 inboards and the axle sleeve 52 relative with it is communicated with.Perimembranous embeds fluid closure member 60,61 respectively in the two ends of axle sleeve 52, and leaves relative with gap with the outer circumferential face of thrust flange 53,54.Form conical plane of inclination 60a, 61a at the position relative with the communication channel 59 of fluid closure member 60,61, the position of facing with this plane of inclination 60a, 61a is as the fluid storage space 64,65 that stores working fluid.On the other hand, between the inner peripheral surface of the outer circumferential face of thrust flange 53,54 and fluid closure member 60,61, form described gap and be communicated with, be provided with the surface tension of utilizing working fluid in addition, working fluid be sealed in the fluid- tight portion 62,63 of hydrodynamic bearing device inboard thus with outer gas (barometric pressure).
As mentioned above, by forming communication channel 59, even the space between the inner peripheral surface of axle 51 the outer circumferential face that is formed with the radial fluid bearing and axle sleeve 52 and be formed with the inner side surface of thrust flange 53,54 of thrust FDB and the both ends of the surface of the axle sleeve 52 relative with it between the space in, even the pressure generation deviation of working fluid and producing under the situation of pressure difference also can be eliminated this pressure difference.That is, adopt the structure that communication channel 59 is set, even the pressure generation deviation of working fluid, the pressure difference that may also be adjusted between working fluid disappears, and makes the bearing function-stable, and can prevent that working fluid from flying out towards the outside.
In this general hydrodynamic bearing device, the gap that forms the radial fluid bearing is extremely small with the gap that forms the thrust FDB, at the assembling hydrodynamic bearing device, when working fluid being filled in the operation in these FDB, working fluid is filled in hydrodynamic bearing device inside, so that it is filled to inside well.But, even so, portion of air remain in the space between the inner peripheral surface of axle 51 the outer circumferential face that is formed with the radial fluid bearing and axle sleeve 52 sometimes and be formed with the inner side surface of thrust flange 53,54 of thrust FDB and the both ends of the surface of the axle sleeve 52 relative with it between the space in.When hydrodynamic bearing device is rotated, sneak in the working fluid with being involved in small bubble sometimes.Like this, sneak into inside when air becomes bubble, when sticking on the dynamic pressure groove 57,58 of the dynamic pressure groove 56 of radial fluid bearing and thrust FDB, the quantity delivered of the working fluid that dynamic pressure groove 56,57,58 causes reduces, because of causing bearing rigidity, bubble descends, rotation instabilities during spinning movement etc. produce the problem that bearing performance descends.
In this hydrodynamic bearing device in the past, during fluid-filled in the assembling procedure, use be the fluid of having removed air (bubble) in advance, but be difficult to remove fully air.In addition, because air is involved in the rotation, can produce bubble in the fluid sometimes.In the past because of not removing the means of these bubbles, so exist the bubble that sticks on the dynamic pressure groove to remain in the shortcoming at dynamic pressure groove and near position thereof like this.
Summary of the invention
The objective of the invention is to, provide a kind of in the action of hydrodynamic bearing device, working fluid circulates in FDB and removes bubble in the working fluid efficiently, working fluid can not leak towards the outside, can not follow rapid change simultaneously, can keep the hydrodynamic bearing device of bearing performance steady state for a long time well.
Hydrodynamic bearing device of the present invention comprises: axle; Have the closed end of the opening end of opening and sealing bearing hole, described axle intermediary is inserted axle sleeve in this bearing hole with rotation posture freely with a gap; Cover the cover plate of the open end side end face of axle sleeve with posture with space, at least one side at the inner peripheral surface of the outer circumferential face of the relative mutually axle of axle and axle sleeve and axle sleeve, be formed with respect to axle sleeve relatively and the radial dynamic pressure groove that supports freely of rotation diametrically in non-contacting mode with axle, on axle sleeve, be formed with the area of space of the Closed End side that makes on the axle sleeve, the communication channel that area of space between the open end side end face of cover plate and axle sleeve is communicated with, in the axle sleeve that comprises between cover plate and the axle sleeve, be filled with working fluid in the space, the radial dynamic pressure flute profile becomes the shape of giving cyclic force to working fluid, when axle is done rotation relatively with respect to axle sleeve, the space of working fluid between axle and axle sleeve, the area of space distolateral with the sealing of this spatial communication, the communication channel that is communicated with the distolateral area of space of this sealing, be communicated in the cover plate of this communication channel and the space between the axle sleeve and circulate.It is characterized in that, form the importing minimum clearance portion that produces wicking near the position the opening portion of the communication channel between the open end side end face of cover plate and axle sleeve to the bearing hole opening end, so that utilize wicking and flow in the bearing hole from the working fluid of communication channel, be not formed with in the area of space between the open end side end face of cover plate and axle sleeve in the zone that imports minimum clearance portion, be formed with the vent that is communicated with outer gas, on the open end side end face of open end side end face opposing backside surface cover plate and axle sleeve or axle sleeve, be formed with the fluid retention space portion of such the be detained working fluid in the space bigger, be communicated with in a circumferential direction with vent so that import minimum clearance portion than the gap that imports minimum clearance portion.
In the said structure, the relative rotation of side do when axle and axle sleeve, then working fluid circulates in the inside of axle sleeve and the space between axle sleeve and the cover plate, when even the dynamic pressure groove of radial fluid bearing etc. is stained with bubble, by described circular flow, disengaging such as the driven indent of bubble and circulating imports minimum clearance portion and incoming fluid is detained with in the space portion time flowing through from communication channel, separates the back from working fluid and discharges from vent.Thus, the bearing performance of rotation instability etc. descends in the time of preventing decline, the spinning movement of the bearing rigidity that causes because of bubble.
The present invention is characterized in that, the fluid retention space portion is made the shape that tilts with respect to circumferencial direction, forms from importing minimum clearance portion more near vent side, big more with the separating distance of the open end side end face of axle sleeve.According to this structure, even impacted from the outside or during the posture rapid change at hydrodynamic bearing device, the air in the fluid retention space portion and the interface of working fluid rest near the vent, can prevent to move towards circumferencial direction, its result can prevent working fluid the spilling towards the outside of following bubble to move.Near position vent becomes the shape that the interface changes at circumferencial direction, so the capillary change of the area at interface and the thing followed reduces.
The present invention, it is characterized in that, near the bearing hole opening end between the open end side end face of the cover plate back side and axle sleeve peripheral part, also be formed with the bearing hole periphery minimum clearance portion that produces wicking, importing minimum clearance portion is connected with bearing hole periphery minimum clearance portion, the working fluid of sending from communication channel utilizes wicking, flows in the bearing hole by importing minimum clearance portion and bearing hole periphery minimum clearance portion.By this structure, from importing working fluid that minimum clearance portion imports, can supply with from the bearing hole opening end of complete circumferentially axle sleeve well by bearing hole periphery minimum clearance portion, also can stably be full of working fluid at the bearing hole opening end of axle sleeve.
The present invention, it is characterized in that, on the inner peripheral surface relative of cover plate with axle, also be formed with the working fluid delay portion that is communicated with and is detained working fluid with outer gas, this working fluid delay portion is made of the plane of inclination that tilts, formation along with separate with the open end side end face of axle sleeve, the internal diameter of cover plate becomes greatly gradually, the surface tension that the internal diameter of working fluid delay portion forms surface tension that is trapped in the working fluid in this working fluid delay portion and the working fluid that faces vent is the shape of balance roughly.By this structure, can prevent the drastic change of interface location and the leakage that changes the working fluid that causes because of the interface.
The present invention, it is characterized in that, on the outer circumferential face of the axle relative with the inner peripheral surface of cover plate, also be formed with the working fluid delay portion that is communicated with and is detained working fluid with outer gas, this working fluid delay portion is made of the plane of inclination that tilts, formation along with separate with the open end side end face of axle sleeve, the external diameter of axle diminishes gradually, the surface tension that described working fluid delay portion forms the working fluid that is trapped in this working fluid delay portion and the surface tension of the working fluid that faces vent be the shape of balance roughly.By this structure, the sealing effect that causes because of surface tension when static, the sealing effect that the centrifugal force that produces because of the axle rotation when also having action brings can prevent the drastic change of interface location and the leakage that changes the working fluid that causes because of the interface.
The present invention, it is characterized in that, on the inner peripheral surface relative of cover plate with axle, also be formed with the working fluid delay portion that is communicated with and is detained working fluid with outer gas, this working fluid delay portion also can form: to tilt along with the internal diameter with the separating of the open end side end face of axle sleeve, cover plate becomes big form gradually, and be inclined to the form that reduces gradually of external diameter of axle, in the axial thickness scope of cover plate, at least a portion of the plane of inclination that forms on the outer circumferential face of described axle is relative with this cover plate.
The present invention, it is characterized in that, the described area of space of the Closed End side on the axle sleeve is the area of space that is equipped with the thrust flange on the front end that is fixed on axle, is located at the opening portion and the spatial communication that is equipped with this thrust flange of the communication channel of the Closed End side on the axle sleeve.
The present invention, it is characterized in that, the described area of space of the Closed End side on the axle sleeve is the area of space that front end and territory, Closed End lateral areas shut by axle form, and is located at the opening portion of communication channel of the described Closed End side on the axle sleeve and this spatial communication that front end faced.
According to hydrodynamic bearing device of the present invention, in the spinning movement of axle, the working fluid that is in the dynamic pressure groove of radial fluid bearing flows towards the dynamic pressure groove direction of thrust FDB, flow through communication channel, and utilize wicking to flow through the narrow clearance portion that forms between the open end side end face of axle sleeve and the cover plate, to the dynamic pressure grooved ring stream of FDB radially.In the circulation of working fluid, the air that contains as bubble in the fluid, that similarly between the open end side end face of axle sleeve and cover plate, form and than the big fluid retention space portion of described clearance portion from fluid breakdown, only air is emitted to the outside from vent, so the air in the working fluid is removed gradually.Working fluid can not leak from vent, thereby can prevent to pollute the HDD device.Especially, the fluid retention space portion made the shape that tilts with respect to circumferencial direction, formation from import minimum clearance portion more near vent side, with the big more shape of separating distance of the open end side end face of axle sleeve, thereby, even impacted from the outside or during the posture rapid change, can be prevented that also working fluid from leaking towards the outside with moving of bubble at hydrodynamic bearing device.Thus, the bearing performance of rotation instability etc. descends in the time of preventing decline, the spinning movement of the bearing rigidity that causes because of bubble, can also prevent the outflow of working fluid towards the outside reliably, improves reliability.
Hydrodynamic bearing device of the present invention is particularly useful for the spindle drive motor of disc drive appts, spool drive unit, capstan driving device, drum drive etc., but is not limited thereto.
Description of drawings
Fig. 1 is the sectional view of spindle drive motor that expression has the hydrodynamic bearing device of example 1 of the present invention.
Fig. 2 A is the sectional view of the same hydrodynamic bearing device of expression, and 2B is the figure of 1 dynamic pressure groove of same hydrodynamic bearing device.
Fig. 3 is the plan view of the same hydrodynamic bearing device of expression.
Fig. 4 A is the cover plate of same hydrodynamic bearing device is seen in expression from the back side figure, and 4B represents the figure with respect to the inclined degree of circumferencial direction of the fluid storage space portion of same hydrodynamic bearing device.
Fig. 5 is the cover plate back side portion that conceptually represents same hydrodynamic bearing device and the stereogram that leaves the space of the upper-end surface of the axle sleeve relative with it.
Fig. 6 is the working fluid reservoir of the same hydrodynamic bearing device of expression and near the sectional view at position thereof.
Fig. 7 A, 7B and 7C are the amplification views of the working fluid reservoir of the same hydrodynamic bearing device of expression.
Fig. 8 conceptually represents the working fluid reservoir in the same hydrodynamic bearing device and the pressure balanced figure of fluid storage space portion.
Fig. 9 is the figure of cover plate of the hydrodynamic bearing device of other examples of the present invention of seeing from the back side of expression.
Figure 10 A is the figure of cover plate of the same hydrodynamic bearing device of other examples of the present invention of seeing from the back side, and 10B represents the figure with respect to the inclined degree of circumferencial direction of the fluid storage space portion of same hydrodynamic bearing device.
Figure 11 is the figure of cover plate of the same hydrodynamic bearing device of other examples of the present invention of seeing from the back side of expression.
Figure 12 is the last sectional view of the hydrodynamic bearing device of expression other examples of the present invention.
Figure 13 is the plan view of cover plate of the hydrodynamic bearing device of expression other examples of the present invention.
Figure 14 A and 14B are the sectional views of the hydrodynamic bearing device of expression other examples of the present invention.
Figure 15 A and 15B are that the plan view of hydrodynamic bearing device of expression example 2 of the present invention and sectional view, 15C are the figure of 1 dynamic pressure groove of the same hydrodynamic bearing device of expression.
Figure 16 is the plan view of the same hydrodynamic bearing device of expression.
Figure 17 is the amplification view of the fluid storage of the same hydrodynamic bearing device of expression with space portion and near position thereof.
Figure 18 is a sectional view of representing hydrodynamic bearing device in the past.
Embodiment
Below, describe with reference to the hydrodynamic bearing device of accompanying drawing example of the present invention.In this example, describe using the situation of this hydrodynamic bearing device in the spindle drive motor of hard disk unit.
(example 1)
Fig. 1 is the sectional view of spindle drive motor that expression has the hydrodynamic bearing device of example 1 of the present invention, Fig. 2 A is the sectional view of the same hydrodynamic bearing device of expression, Fig. 3 is the plan view of the same hydrodynamic bearing device of expression, and Fig. 2 A is the II-II line sectional view of Fig. 3.For the ease of understanding, as shown in Figures 1 and 2, the following description is the opening end in the bearing hole of axle sleeve to be configured in the situation that top, closed end be configured in the below describe, and is not limited to such configuration during actual certainly the use.
Among Fig. 1 and Fig. 2, parts use following material.
Axle 1 uses stainless steel, and flange 3 is fixed on the axle 1 integratedly and is formed with the dynamic pressure groove, so use than the little stainless steel of stainless steel hardness that is used for axle 1.Axle sleeve 2 uses Cuprum alloy or Ferrious material, and the surface is implemented nickel and electroplated.Thrust plate 4 uses the surperficial stainless steel of being crossed by mirror ultrafinish, and the situation of DLC coating is also arranged.Cover plate 5 is formed by resin.Wheel hub 16 uses by cutting property, good stainless steel or the aluminum alloy of anti-extraneous gas.Magnet 17 is that neodymium is the magnet of resin.Stator core 19 is made of electromagnetic steel plate, is wound with coil 18.Substrate 15 uses surface treated aluminum alloy or Ferrious material.Substrate 15 is the occasion of aluminum alloy, and the ring-type of configuration Ferrious material attracts plate on the substrate under the magnet 17 mostly.Coil 18 solderings are that FPC draws towards the motor outside on the FPC of resin at polyimide.In addition, in order to ensure coil 18 insulation with substrate 15, PET is that the insulating trip of resin is configured on the substrate 15 under the coil.
As Fig. 1～shown in Figure 3, the hydrodynamic bearing device of this spindle drive motor comprises: axle 1; Be fixed on the substrate 15 of spindle drive motor, have the bearing hole 2a, the axle sleeve 2 that axle 1 is inserted with rotation posture freely by gap (space) of closed end 2ab of the downside of the opening end 2aa that comprises open upper side and sealing; By outer embedding in conjunction with or screw etc. is fixed on the underpart of axle 1 and the sealing of bearing hole 2a distolateral be the 2ac of large diameter hole portion with the large diameter thrust flange 3 of the posture configuration that has the gap with respect to the 2ac of this large diameter hole portion; The posture that has a gap with the lower surface with thrust flange 3 relatively is fixed on the thrust plate 4 of the bottom of axle sleeve 2, except that these structures, also be provided with by having the cover plate 5 that translucent material constitutes, this cover plate 5 covers the upper-end surface (open end side end face) of axle sleeve 2 with the posture with space, and has 1 vent 13 that is communicated with outer gas.In this hydrodynamic bearing device, be equipped with 1 communication channel 6 extending in parallel with axle center O at the position of the outer side face of axle sleeve 2 (for example, this diameter is about 0.2～0.6mm), by this communication channel 6, the 2ac of large aperture portion (area of space of Closed End side) and opening end (2aa) side end face of cover plate 5 and axle sleeve 2 of being located at the closed end 2ab side of bearing hole 2a is that the area of space between the upper-end surface is communicated with.
The inner space that comprises the axle sleeve 2 between cover plate 5 and the axle sleeve 2 (promptly, the interior space in the space that is communicated with the position between space in space between the inner peripheral surface of axle 1 outer circumferential face and axle sleeve 2, the 2ac of large diameter hole portion of bearing hole 2a, the 2ac of large diameter hole portion of bearing hole 2a and the communication channel 6, communication channel 6, upper-end surface and the space between the cover plate 5 (but, except the position of vent 13) of axle sleeve 2) in be filled with and lubricate wet goods working fluid 20.Shown in Fig. 6, Fig. 7 A amplify, on the inner peripheral surface that faces axle 1 of cover plate 5, form more and enlarge more to opening side, be formed with the working fluid reservoir 23 that is communicated with, stores working fluid 20 with outer gas.Axle sleeve 2 and cover plate 5, the 2f of peripheral outer lips portion, 5f that will be integrally formed respectively by Bond 21 fix, and constitute working fluid 20 and do not leak towards the outside from the axle sleeve 2 and the mating face of cover plate 5.
Inner peripheral surface (also can be arranged on the outer circumferential face of axle 1 or the inner peripheral surface of axle sleeve 2 and the outer circumferential face both sides of axle 1) at axle sleeve 2, form 2 dynamic pressure grooves 7,8 of herring-bone form pattern etc. up and down, by after the rotary driving force chatted when making axle 1 with axle sleeve 2 relative rotations, the power of the working fluid 20 that utilization is assembled by this dynamic pressure groove 7,8 constitutes and makes axle 1 and axle sleeve 2 go up intermediary at radially (radial direction) specified gap and the supported freely radial fluid bearing of rotation are arranged.In addition, at the upper surface of thrust flange 3 and lower surface (perhaps, also can be arranged on the lower surface of the axle sleeve relative 2 and the upper surface of thrust plate 4 with it, or all surface of the upper surface of the lower surface of the upper and lower surface of thrust flange 3 and axle sleeve 2 and thrust plate 4) forms the dynamic pressure groove 9 of helical pattern etc., 10, constituted when making the thrust flange 3 that is installed on the axle 1 by described rotary driving force etc. with axle sleeve 2 relative rotations, utilization is by this dynamic pressure groove 9, the power of 10 working fluids of assembling 20 makes axle 1 and axle sleeve 2 in thrust direction (axis direction) intermediary specified gap and the supported freely thrust FDB of rotation be arranged.Here, the dynamic pressure groove 7,8 that constitutes the radial fluid bearing is made well-known man type, upside and downside at the outer circumferential face of axle 2 form at 2 places totally, but the dynamic pressure groove 8 of downside, from the groove of its oblique updip in top and the groove that tiltedly has a down dip is equal length, and upside dynamic pressure groove 7 is shown in Fig. 2 B, forms longlyer than the groove 7b that tiltedly has a down dip from the top from the groove 7a of its oblique updip in top, when rotation drove, the working fluid 20 in this gap was sent towards the below energetically by the dynamic pressure groove 7 of this upside.
As shown in Figure 1, on the axle 1 on the periphery of the outstanding outstanding axial region 1a of the bearing hole 2a of axle sleeve 2, be pressed into state for example be embedded with outward fixedly the rotating member of magnetic recording disc promptly, wheel hub 16.In this example 1, the periphery by base part of wheel hub 16 is equipped with rotor magnet 17.The stator core 19 that is wound with stator coil 18 relatively is installed on the pedestal 15 with rotor magnet 17.Constituted giving the rotary driving part of the spindle drive motor of rotary driving force between axle 1 and the axle sleeve 2 by this rotor magnet 17 and stator core 19.
In addition, shown in Fig. 2 A, the upper-end surface relative with cover plate 5 on the axle sleeve 2 is roughly plane shape.By contrast, as Fig. 2 A, Fig. 3～Fig. 5 is (among Fig. 5, for easy understanding, the separated space of the back side portion that conceptually represents cover plate 5 and the upper-end surface of the axle sleeve 2 relative) shown in it, cover plate 5 its back side portions are adapted to: near the peripheral part the bearing hole 2a opening end of the opening portion near zone of the communication channel 6 of the upper-end surface of axle sleeve 2 opening and axle sleeve 2, with the back portion of its corresponding cover plate 5 with the separating distance of the upper-end surface of relative axle sleeve 2 is the size b (with reference to Fig. 5) that produce wicking with it, form the gap that utilizes wicking and flow at the bearing hole 2a of axle sleeve 2 inner peripheral surfaces and (be called the minimum clearance portion 11 that imports, bearing hole periphery minimum clearance portion 12, among Fig. 4 A, the importing minimum clearance face 5b that faces importing minimum clearance portion 11 of the back portion of expression cover plate 5, face the bearing hole periphery minimum clearance face 5c of bearing hole periphery minimum clearance portion 12).In addition, shown in Fig. 3, Fig. 4 A, this importing minimum clearance portion 11 forms the shape of the opening end of the bearing hole 2a that is connected to axle sleeve 2 from the opening portion vicinity of communication channel 6 by bearing hole periphery minimum clearance portion 12.In this example 1, import minimum clearance portion 11 and make the roughly roughly umbrella shape of 30 degree angle of releases, be formed at the scope bigger than the opening portion of communication channel 6.The diameter of the opening end of the bearing hole 2a of the upper-end surface of axle sleeve 2 for example is 2.8～3.2mm, and bearing hole periphery minimum clearance face 5c is circular, forms from the opening end periphery of the bearing hole 2a radial direction dimension width with 0.2～0.6mm.The Separation that imports minimum clearance portion 11 and bearing hole periphery minimum clearance portion 12 for example is 0.03mm～0.15mm.In this example 1, the Separation that imports minimum clearance portion 11 and bearing hole periphery minimum clearance portion 12 is with respect to radially also being certain.
Especially, position beyond importing minimum clearance portion 11 in the back side portion of cover plate 5, the bearing hole periphery minimum clearance portion 12, caving in becomes big space, gap than importing minimum clearance portion 11 and bearing hole periphery minimum clearance portion 12, make can store working fluid 20 fluid retention space portion 14 in a circumferential direction with import minimum clearance portion 11 and vent 13 and be communicated with.This fluid retention space portion 14 for example is internal diameter 3.2～3.8mm, and external diameter is 5.5～6.3mm, and minimum clearance is 0.03～0.15mm, and the maximal clearance is 0.2～0.3mm degree.Vent 13, its diameter for example is 0.2～1.0mm degree, be formed with at the position that is provided with this vent 13 by spot-facing form as the recess 22 of buffer space (for example, diameter 0.6～1.0mm, the degree of depth is 0.1～0.3mm degree), but the position of the fluid retention space portion 14 that links to each other with this vent 13 and recess 22 (being called the 14a of maximum space portion) forms the shape of inclination with respect to circumferencial direction, with the separating distance with the upper-end surface of axle sleeve 2 is maximum,, increase near the described maximum space 14a of portion from described importing minimum clearance portion 11 from upper-end surface (open end side end face) separating distance of axle sleeve 2.In this example 1, the Separation of fluid retention space portion 14 is with respect to radially being certain.In addition, in this example 1, with vent 13 that outer gas is communicated be arranged on the cover plate 5 to overlook with axle center O be on the opposite position of the opening portion of center and communication channel 6.D among Fig. 3 is the sense of rotation of axle 1.In addition, form recess 22 at described vent 13, even the situation that ambient temperature rising etc. is set of hydrodynamic bearing device occurs under the state that is full of working fluid 20, the interface K of working fluid 20 rests in the recess 22, and working fluid 20 can not let out from vent 13.
Shown in Fig. 7 A amplifies, form the working fluid delay portion 23 that enlarges towards opening side on cover plate 5 and the inner peripheral surface that axle 1 is faced mutually, plane of inclination 23a by the earth tilt that narrows down towards the below forms, as described later, the diameter Dt of the upper end of plane of inclination 23a and the diameter d t of lower end are set for: even reduce the occasion that the interface location at the position that makes fluid retention space portion 14 changes because of evaporation etc. at working fluid, in this working fluid delay portion 23, the scope inner equilibrium that move in the 23a of plane of inclination at the interface.
Cover plate side in Fig. 7 A is provided with the plane of inclination, but also can be shown in a side as Fig. 7 B the plane of inclination is set.This occasion, the sealing effect that surface tension causes when static, the sealing effect that the centrifugal force that produces because of the axle rotation when moving in addition brings.
Shown in Fig. 7 C, in the cover plate side plane of inclination is set, simultaneously relative with at least a portion of the plane of inclination of axle 1 in the scope of the axial thickness of cover plate 5, when liquid level will change, the sealing both sides that utilize sealing that surface tension forms and centrifugal force to form prevented leakage of oil.
In addition,, when assembling is carried out working fluid 20 oilings behind this hydrodynamic bearing device, fall to the outside in order to prevent working fluid 20 as Fig. 2 A, shown in Figure 3, the upper surface peripheral part of cover plate 5 also be formed with towards above outstanding projecting strip part 24.This projecting strip part 24 for example is internal diameter 6～8mm, height 0.03～0.1mm degree.
In said structure, when axle 1 is done relative rotation with axle sleeve 2 by the rotary driving force of spindle drive motor, the power of the power of the working fluid 20 that utilization is assembled by the dynamic pressure groove 7,8 of radial fluid bearing and the working fluid 20 assembled by the dynamic pressure groove 9,10 of thrust FDB, axle 1 is to keep the state of specified gap supported with respect to axle sleeve 2.Utilization is by the power of the working fluid 20 of dynamic pressure groove 7 gatherings of the radial fluid bearing of upside, working fluid 20 between axle 1 and the axle sleeve 2 is carried towards the below, thus, working fluid 20 flows through space, the space in the communication channel 6 between space, axle sleeve 2 and the thrust plate 4 between thrust flange 3 and the axle sleeve 2 successively, imports minimum clearance portion 11 and bearing hole periphery minimum clearance portion 12, flow into the space between axle 1 and the axle sleeve 2 once more, working fluid 20 is circulation energetically between these spaces.The part of the working fluid 20 that imports in importing minimum clearance portion 11 from communication channel 6, also incoming fluid is detained with space portion 14 and passes through once again in the space between bearing hole periphery minimum clearance portion 12 inflows spool 1 and the axle sleeve 2 on one side.
Therefore, when even the dynamic pressure groove 9,10 of dynamic pressure groove of radial fluid bearing 7,8 and thrust FDB etc. is stained with bubble, by described circular flow, disengagings such as the driven indent 7,8 of bubble, dynamic pressure groove 9,10 and circulating, flow through when importing minimum clearance portion 11 from communication channel 6, the low fluid retention of feed pressure is with in the space portion 14.When the low fluid retention of feed pressure is used in the space portion 14, the size of this bubble also increases, so situation about entering once more in high importing minimum clearance portion 11 of pressure and the bearing hole periphery minimum clearance portion 12 reduces, bubble is discharged from vent 13 with separating from working fluid 20 in the space portion 14 in fluid retention.
According to this structure, when driving, normal rotation also in working fluid, discharges bubble, and its result can prevent that the bearing rigidity that causes because of bubble from descending and the bearing performance decline of rotation instability etc. during spinning movement, the raising reliability.
According to this hydrodynamic bearing device, not only the inner peripheral surface that faces axle 1 at cover plate 5 is provided with working fluid delay portion 23, and is provided with the fluid retention space portion 14 of big volume between axle sleeve 2 and cover plate 5.Therefore, even under the situation that fluid retention reduces with the action fluid of space portion 14,, just can keep circulatory function as long as in importing minimum clearance portion 11 and bearing hole periphery minimum clearance portion 12, be full of working fluid 20.
Especially according to the present invention, fluid retention space portion 14 made the shape that tilts with respect to circumferencial direction, formation is from importing with minimum clearance 11 near the 14a of maximum space portion that is provided with vent 13, with the open end side end face of axle sleeve 2 be that the separating distance of upper surface is big more, thereby, even hydrodynamic bearing device is impacted from the outside or during the posture rapid change, the air in the fluid retention space portion 14 and the interface of working fluid 20 rest near the position the vent 13, can prevent to move towards circumferencial direction, its result can prevent working fluid 20 the spilling towards the outside of following bubble to move.Near the position vent, the storage area sectional area of fluid retention space portion is big more, and, shown in interface location P1, the P2 when reducing as working fluid among Fig. 3 20, become the shape that the interface changes at circumferencial direction all the time, so the capillary change in the area at interface and the following fluid retention space portion 14 is little.
Near the bearing hole opening end between the upper surface of the back side of cover plate 5 and axle sleeve 2 peripheral part, also be formed with the bearing hole periphery minimum clearance portion 12 that produces wicking, so supply with from the bearing hole 2a of complete circumferentially axle sleeve 2 well by this bearing hole periphery minimum clearance portion 12 from the working fluid 20 that imports 11 importings of minimum clearance portion, in the bearing hole 2a of axle sleeve 2, stably be full of working fluid 20.
Make the surface tension shape of balance roughly that makes surface tension that is trapped in the working fluid 20 in the working fluid delay portion 23 and the fluid retention space portion 14 that faces vent 13 by the internal diameter (the diameter Dt of the upper end of plane of inclination 23a and the diameter d t of lower end) that working fluid is detained portion 23, just can prevent the drastic change of interface location of the working fluid 20 in the working fluid delay portion 23 and the leakage that the interface changes the working fluid that causes.
Here, this point is elaborated.
Fig. 8 is the pressure balanced figure that conceptually represents working fluid reservoir 23 and fluid retention space portion 14 on the axle sleeve upper surface of this hydrodynamic bearing device.Here, A is the pressure that the surface tension at the interface 1 of working fluid delay portion 23 causes, B is the pressure of the volume flow rate that causes of the difference of interface location, and C is the pressure that the surface tension at the interface of fluid retention space portion 14 O causes.Y is the surface tension [N/m] of oil (working fluid), and ρ is the density [kg/m of oil
3], Li is the oily interface on the interface I and the contact length of member, Ai is the oily interfacial surface area of interface I, Lo is the oily interface on the O of interface and the contact length of member, Ao is the oily interfacial surface area of interface O, hi is the height from the axle sleeve upper surface to interface I, and ho is the average height (t/2) from the axle sleeve upper surface to interface O, and θ is member and oily interface contact angle.
In model shown in Figure 8, pressure balance type is
(formula 1)
A＝B+C [Pa]
Wherein, the A of formula 1, B, C are as follows.
(formula 2)
A＝(y·cosθ×Li)/Ai
(formula 3)
B＝ρ·(hi-ho)
(formula 4)
C＝(y·cosθ×Lo)/Ao
(formula 2), (formula 3), (formula 4) substitution (formula 1) are obtained
(formula 5)
Li/Ai＝{1/(y·cosθ)}×[ρ·(hi-ho)+{(y·cosθ)+Lo}/Ao]
With following (formula 6), (formula 7) substitution (formula 5), the right is made as Z, then
(formula 6)
Li＝π(ds+Dts)
(formula 7)
Ai＝π{(Dts/2)
2-(ds/2)
2}
(formula 8)
(ds+Dts)/{(Dts/2)
2-(ds/2)
2}＝Z
(formula 8) launched,, find the solution the diameter Dts at working fluid delay portion 23 places, obtain according to the formula of separating
(formula 9)
Dts＝{1+SQRT(1+Z(ds+Z×ds
2/4))}/(Z/2)
Find the solution oily interface diameter Dts when maximum and hour from (formula 9), can fully satisfy this Interface Moving scope by the internal diameter (dt, Dt) of setting end sealing for, the surface tension that makes surface tension that is trapped in the working fluid 20 in the working fluid delay portion 23 and the fluid retention space portion 14 that faces vent 13 is balance roughly, thus, can prevent the leakage of the drastic change of interface location and the working fluid that the interface change causes of the working fluid 20 in the working fluid delay portion 23.
In this example 1, unnecessary oil is stored in the working fluid detention space portion 14 in order to prolong bearing life, so only have a spot of oil in the working fluid delay portion 23, even tilt angle big extremely to a certain degree (for example 50 °～60 °) also have for the enough endurance of oil leakage.Even move with the consumption or the temperature change of oil at the oily interface of working fluid detention space portion 14, the variation of surface area is also less, so have the little such feature of the level change of working fluid delay portion 23.
In above-mentioned example 1, the upper surface peripheral part of cover plate 5 form towards above outstanding projecting strip part 24, so when behind the assembling hydrodynamic bearing device, carrying out working fluid 20 oilings, can prevent that by projecting strip part 24 working fluid 20 from dropping from the upper surface of cover plate 5, can improve operating efficiency thus, and prevent the minimizing of the charging quantity of working fluid 20 in axle sleeve 2, improve reliability.
As shown in figure 13, also projecting strip part 24 can be set, but form the anti-oil groove 25 that the coating oil-proofing agent is used, see that from the plane formation surrounds the shape of working fluid delay portion 23 and vent 13 from the outside, oil-proofing agent is coated in this anti-oil groove 25, when supplying with working fluid 20, working fluid 20 is not flowed out laterally.
In the above-mentioned example 1, shown in Fig. 4 A, the shape plane of the 14a of maximum space portion that imports minimum clearance portion 11 and fluid retention space portion 14 is seen as fan-shaped situation to be narrated, but be not limited thereto, as shown in Figure 9, the boundary line of its circumferencial direction also can become parallel in shape each other.In addition, shown in Figure 10 A, can not form in opposite position importing minimum clearance portion 11 and fluid retention space portion 14 point with respect to axle center O yet.And, as shown in figure 11, also can with communication channel 6 with import that minimum clearance portion 11, vent 13 be provided with 2 places with the 14a of maximum space portion or more than 2 places.
In addition, fluid retention space portion 14 is depicted as necessarily with respect to conception among the angle of inclination of circumferencial direction such as Fig. 4 B and Figure 10 B, but be not limited thereto, also can be shown in dotted line, the angle of inclination of intermediate portion reduces, or makes other shapes, as long as meet the following conditions, promptly, form the shape that tilts with respect to circumferencial direction, so that from importing minimum clearance portion 11 more near vent 13 sides, then the separating distance from the open end side end face of axle sleeve is big more.
In above-mentioned example 1, underpart at axle 1 had large diameter thrust flange 3, be that so-called situation with flanged is illustrated, but be not limited thereto, shown in Figure 14 A, also applicable to not having thrust flange 3, but become the structure of the dynamic pressure groove that the thrust FDB uses at the mutual opposing side of the underpart of axle 1 and thrust plate 4 at least one square, or it is not shown, do not have thrust flange 3 but by being located at the hinge portion of axle 1 underpart, on thrust direction, make the structure of position limit with respect to the sheet material of this closed area of sealing, certainly, even the structure of this so-called flangeless axle also can obtain same effect.
And in the above-mentioned example 1, as shown in Figure 14B, fluid retention space portion 14 is formed on the cover plate 5, even but be formed on the open end side end face of axle sleeve 2 and also can obtain identical effect.
(example 2)
Below the hydrodynamic bearing device of the structure different with the hydrodynamic bearing device of the example 1 of above explanation is described.For the ease of understanding, shown in Figure 15 B, the following description is the opening end in the bearing hole of axle sleeve to be configured in the situation that top, closed end be configured in the below describe, but is not limited to the direction of this configuration.
Shown in Figure 15 A, 15B, this hydrodynamic bearing device comprises: axle 71; Have the opening end that comprises open upper side and sealing downside closed end bearing hole 72a, with the gapped axle sleeve 72 that inserts with rotation posture freely of axle 71 intermediaries (space); Be arranged on an axle end (underpart among Figure 15 B) of 71, to have the large diameter thrust flange 73 of the posture configuration in gap by the underpart end face with respect to axle sleeve 72; Relatively be fixed on the thrust plate 74 of the bottom of axle sleeve 72 with the posture that has a gap with thrust flange 73, except that these structures, also be provided with cover plate 75, this cover plate 75 leaves the upper-end surface (open end side end face) that covers axle sleeve 72 with gap, and a part has the vent 83 that is communicated with outer gas.In this hydrodynamic bearing device, be equipped with 1 communication channel 76 that extends with axis parallel at the position of the outer side face of axle sleeve 72, by this communication channel 76, the area of space between the upper-end surface of the area of space that upper surface faced of thrust plate 74 (area of space of Closed End side) and cover plate 75 and axle sleeve 72 is communicated with.In the inner space that surrounds by axle sleeve 72 that is covered by cover plate 75 and thrust plate 74 (promptly, the interior space of clearance space between clearance space, thrust flange 73 and the thrust plate 74 between the lower surface of the space between the inner peripheral surface of axle 71 outer circumferential face and axle sleeve 72, thrust flange 73 and the axle sleeve 72 relative and near the major diameter inner peripheral surface thereof, communication channel 76, upper-end surface and the space between the cover plate 5 (but, except the position of vent) of axle sleeve 72 with it) in be filled with and lubricate wet goods working fluid 90.Among Figure 15 B 84 is the working fluid delay portions that are communicated with, are detained working fluid 90 with outer gas, is formed on the shape that enlarges more towards opening side more on the inner peripheral surface that faces axle 71 of cover plate 75.
Inner peripheral surface (also can be arranged on the outer circumferential face of axle 71 or the inner peripheral surface of axle sleeve 72 and the outer circumferential face both sides of axle 71) at axle sleeve 72 forms 2 dynamic pressure grooves 77,78 up and down, when the rotary driving force by scheming outer motor etc. makes axle 71 with axle sleeve 72 relative rotations, the power of the working fluid 90 that utilization is assembled by this dynamic pressure groove 77,78 constitutes and makes axle 71 and axle sleeve 72 go up intermediary at radially (radial direction) specified gap and the supported freely radial fluid bearing of rotation are arranged.In addition, upper surface in thrust flange 73 (also can be arranged on the lower surface of the axle sleeve relative with it 72 and the upper surface of thrust plate 74 with lower surface, or all faces of the upper surface of the lower surface of the upper and lower surface of thrust flange 73 and axle sleeve 72 and thrust plate 74) form dynamic pressure groove 79,80, constituted when making the thrust flange 73 that is installed on the axle 71 by described rotary driving force etc. with axle sleeve 72 relative rotations, utilization is by this dynamic pressure groove 79, the power of 80 working fluids of assembling 90, making thrust flange 73 go up intermediary with axle sleeve 72 and thrust plate 74 in thrust direction (axis direction) has specified gap and the supported freely thrust FDB of rotation.Here, the dynamic pressure groove 77,78 that constitutes the radial fluid bearing is made well-known man type, upside and downside at the outer circumferential face of axle 71 form at 2 places totally, but the dynamic pressure groove 78 of downside, from the groove of its oblique updip in top and the groove that tiltedly has a down dip is equal length, and upside dynamic pressure groove 77 is shown in Figure 15 C, forms longlyer than the groove 77b that tiltedly has a down dip from the top from the groove 77a of its oblique updip in top, by the dynamic pressure groove 77 of this upside, the working fluid 90 in this gap was sent towards the below energetically when rotation drove.
In addition, the upper-end surface relative with cover plate 5 on the axle sleeve 2 is plane shape.By contrast, cover plate 75 its back side portions (face relative with the upper-end surface of axle sleeve 72) are adapted to: at the opening portion near zone of the communication channel 76 of the upper-end surface of axle sleeve 72 opening, form the gap (being called the minimum clearance portion 81 that imports) that utilizes wicking and flow at the bearing hole 72a of the inner peripheral surface of axle sleeve 72, this imports minimum clearance portion 81 as Figure 16 and shown in Figure 17, forms the opening end that is connected to the bearing hole 72a of axle sleeve 72 from the opening portion vicinity of communication channel 76.Position beyond the above-mentioned importing minimum clearance portion 81 in the one of the back side of cover plate 75, shown in the dotted line among Figure 15 B, become the shape of depression, the position that has formed outer week significantly towards the fluid retention of top depression with space portion 82, and be formed with the plane of inclination 75a of depression, from this fluid retention central side of space portion 82 towards radial direction, the gap of the upper-end surface of itself and axle sleeve 72 is reduced gradually, these fluid retention are with space portion 82 and face the position of plane of inclination 75a, form and do not produce the wicking size of size like that, can be detained working fluid 90.On the cover plate 75, to overlook with axle center O be on the position opposite with the opening portion of communication channel 76, center, and the vent 83 that is communicated with outer gas is set.D among Figure 16 is the sense of rotation of axle 71.
In this structure, when axle 71 and axle sleeve 72 by the relative rotations such as motor rotary driving force outside the figure, the power of the working fluid 90 that then utilizes the power of the working fluid of being assembled by the dynamic pressure groove 77,78 of radial fluid bearing 90 and assembled by the dynamic pressure groove 79,80 of thrust FDB, axle 71 is to keep the state of specified gap supported with respect to axle sleeve 72.Again, utilization is by the power of the working fluid 90 of dynamic pressure groove 77 gatherings of the radial fluid bearing of upside, working fluid 90 between axle 71 and the axle sleeve 72 is carried towards the below, thus, working fluid 90 flows through space, the space in the communication channel 76 between space, axle sleeve 72 and the thrust plate 74 between thrust flange 73 and the axle sleeve 72 successively and imports minimum clearance portion 81, flow into the space between axle 71 and the axle sleeve 72 once more, working fluid 90 is circulation energetically between these spaces.The part of the working fluid 90 that in importing minimum clearance portion 81, imports from communication channel 76, Yi Bian also incoming fluid be detained use space portion 82 flow into once again spools 71 and axle sleeve 72 between the space in.
Therefore, when even the dynamic pressure groove 79,80 of dynamic pressure groove of radial fluid bearing 77,78 and thrust FDB etc. is stained with bubble, by described circular flow, disengagings such as the driven indent 77,78 of bubble, dynamic pressure groove 79,80 and circulating, flow through the minimum clearance portion 81 that imports from communication channel 76, when the incoming fluid delay is used in the space portion 82, discharge from the working fluid separation and from vent 83.Thus, by this structure, even when normal rotation drives, also in working fluid, discharge bubble, its result, the bearing performance of rotation instability etc. descends in the time of preventing the decline of the bearing rigidity that bubble causes and spinning movement.
According to this hydrodynamic bearing device, not only the inner peripheral surface that faces axle 71 at cover plate 75 is provided with working fluid delay portion 84, and is provided with the fluid retention space portion 82 of big volume between axle sleeve 72 and cover plate 75.Therefore, when fluid retention reduces because of evaporation waits with the action fluid of space portion 82, at first, with respect to the interface K of the working fluid of air shown in the dotted line among Figure 15 A, become the longshore current body and be detained the roughly circular arc ring-type of using space portion 82, and, even working fluid reduces, interface K becomes along the shape of plane of inclination 75a, just in case when this fluid retention uses the working fluid of space portion 82 to reduce because of evaporation waits, be full of working fluid, just can keep circulatory function as long as import in the minimum clearance portion 81, event can be extremely for a long time and is kept bearing performance well, realizes long lifetime.
Claims (14)
1. a hydrodynamic bearing device comprises: axle (1,71); Have the closed end of the opening end of opening and sealing bearing hole, described axle intermediary is inserted axle sleeve (2,72) in this bearing hole with rotation posture freely with a gap; Cover the cover plate (5,75) of the open end side end face of described axle sleeve,
At least one side of the outer circumferential face of the described axle that described axle is relative mutually with described axle sleeve and the inner peripheral surface of described axle sleeve, be formed with respect to described axle sleeve relatively and the radial dynamic pressure groove (7,8,77 that supports freely of rotation diametrically in non-contacting mode with described axle, 78)
On described axle sleeve, be formed with the communication channel (6,76) that the area of space between the open end side end face of the area of space that makes the described Closed End side on the axle sleeve, described cover plate and described axle sleeve is communicated with,
In the axle sleeve that comprises between described cover plate and the described axle sleeve, maintain working fluid in the space,
Described radial dynamic pressure groove (7,8,77,78) forms the shape of giving cyclic force to described working fluid,
When described axle is done rotation relatively with respect to described axle sleeve, the space of working fluid between described axle and described axle sleeve, with the distolateral area of space of the described sealing of this spatial communication, with described communication channel, the described cover plate that is communicated in this communication channel and the space between the described axle sleeve that the distolateral area of space of this sealing is communicated with in circulate, it is characterized in that
Form the importing minimum clearance portion (11 that produces wicking near the position the opening portion of the communication channel between the open end side end face of described cover plate and described axle sleeve to the bearing hole opening end, 81), so that utilize wicking and flow in the described bearing hole from the working fluid of described communication channel
The position that is not formed with described importing minimum clearance portion on described cover plate is formed with the vent (13,83) that is communicated with outer gas,
On the open end side end face of open end side end face opposing backside surface described cover plate and described axle sleeve or axle sleeve, being formed with caves in becomes the big fluid retention space portion (14 space, that can be detained working fluid in gap than described importing minimum clearance portion, 82), so that described importing minimum clearance portion (11,81) be communicated with in a circumferential direction with described vent (13,83).
2. hydrodynamic bearing device as claimed in claim 1, it is characterized in that, described fluid retention space portion (14) made the shape that tilts with respect to circumferencial direction, formation is from the approaching more described vent of described importing minimum clearance portion (11) (13) side, and is big more with the separating distance of the open end side end face of axle sleeve.
3. hydrodynamic bearing device as claimed in claim 1 is characterized in that, near the peripheral part the bearing hole opening end between the open end side end face of the cover plate back side and axle sleeve also is formed with the bearing hole periphery minimum clearance portion (12) that produces wicking,
Import minimum clearance portion (11) and be connected with described bearing hole periphery minimum clearance portion (12),
The working fluid of sending from communication channel (6) utilizes wicking, flows in the described bearing hole by described importing minimum clearance portion (11) and described bearing hole periphery minimum clearance portion (12).
4. hydrodynamic bearing device as claimed in claim 1 is characterized in that, on the inner peripheral surface relative with axle of cover plate, also is formed with the working fluid delay portion (23,84) that is communicated with and is detained working fluid with outer gas,
This working fluid delay portion (23,84) is made of the plane of inclination that tilts, form along with separate with the open end side end face of axle sleeve, the internal diameter of cover plate (5) becomes greatly gradually,
The surface tension of the surface tension that described working fluid delay portion (23,84) forms the working fluid that is trapped in this working fluid delay portion (23,84) and the working fluid that faces vent (13,83) is the shape of balance roughly.
5. hydrodynamic bearing device as claimed in claim 1 is characterized in that, on the outer circumferential face of the axle relative with the inner peripheral surface of cover plate, also is formed with the working fluid delay portion (23,84) that is communicated with and is detained working fluid with outer gas,
This working fluid delay portion (23,84) is made of the plane of inclination that tilts, form along with separate with the open end side end face of axle sleeve, the external diameter of axle (1) diminishes gradually,
The surface tension of the surface tension that described working fluid delay portion (23,84) forms the working fluid that is trapped in this working fluid delay portion (23,84) and the working fluid that faces vent (13,83) is the shape of balance roughly.
6. hydrodynamic bearing device as claimed in claim 1 is characterized in that, on the inner peripheral surface relative with axle of cover plate, also is formed with the working fluid delay portion (23,84) that is communicated with and is detained working fluid with outer gas,
This working fluid delay portion (23,84) form: to tilt along with the internal diameter with the separating of the open end side end face of axle sleeve, cover plate (5) becomes big form gradually, and be inclined to the form that reduces gradually of external diameter of axle (1), in the axial thickness scope of cover plate, at least a portion of the plane of inclination that forms on the outer circumferential face of described axle is relative with this cover plate.
7. hydrodynamic bearing device as claimed in claim 1 is characterized in that, described importing minimum clearance portion (11,81) makes near the position opening portion of communication channel near the bearing hole opening end, and is just more little at interval.
8. hydrodynamic bearing device as claimed in claim 1 is characterized in that, the described area of space of the Closed End side on the axle sleeve is the area of space that is equipped with the thrust flange (3,73) on the front end that is fixed on axle,
Be located at the opening portion and the spatial communication that is equipped with this thrust flange (3,73) of the communication channel (6,76) of the described Closed End side on the axle sleeve (2,72).
9. hydrodynamic bearing device as claimed in claim 1 is characterized in that, the described area of space of the Closed End side on the axle sleeve is the area of space that front end and territory, Closed End lateral areas shut (4) by axle form,
Be located at the opening portion of communication channel (6) of the described Closed End side on the axle sleeve and this spatial communication that front end faced.
10. hydrodynamic bearing device as claimed in claim 1 is characterized in that, described vent is formed on the opening portion of the described communication channel center with respect to axle roughly to become on the point-symmetric position.
11. hydrodynamic bearing device as claimed in claim 1 is characterized in that, the back side almost parallel of the end face of described axle sleeve and described cover plate is so that described importing minimum clearance portion (11,81) keeps certain clearance near the opening portion of described communication channel.
12. hydrodynamic bearing device as claimed in claim 1 is characterized in that, near described vent, is provided with the big space, space that Billy can make described working fluid flow into wicking.
13. hydrodynamic bearing device as claimed in claim 12 is characterized in that, Billy is the tubular space with diameter bigger than described vent with the big described space, space that wicking can make described working fluid flow into.
14. hydrodynamic bearing device as claimed in claim 1 is characterized in that, is used for spindle drive motor.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2004222514A JP2006038179A (en) | 2004-07-29 | 2004-07-29 | Fluid bearing device |
| JP2004222514 | 2004-07-29 | ||
| JP2004356110 | 2004-12-09 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1727707A CN1727707A (en) | 2006-02-01 |
| CN100356074C true CN100356074C (en) | 2007-12-19 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB2005100885237A Expired - Fee Related CN100356074C (en) | 2004-07-29 | 2005-07-29 | Hydrodynamic bearing device |
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| Country | Link |
|---|---|
| JP (1) | JP2006038179A (en) |
| CN (1) | CN100356074C (en) |
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|---|---|---|---|---|
| JP4642682B2 (en) * | 2006-03-20 | 2011-03-02 | Ｎｔｎ株式会社 | Hydrodynamic bearing device and manufacturing method thereof |
| KR100771356B1 (en) * | 2006-03-27 | 2007-10-29 | 삼성전기주식회사 | Hydrodynamic bearing with an additional reservoir |
| JP5154057B2 (en) * | 2006-10-27 | 2013-02-27 | Ｎｔｎ株式会社 | Hydrodynamic bearing device |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH06137320A (en) * | 1992-10-29 | 1994-05-17 | Nippon Seiko Kk | Dynamic pressure fluid bearing device |
| JPH07310747A (en) * | 1994-05-13 | 1995-11-28 | Nippon Ferrofluidics Kk | Dynamic pressure bearing device |
| US5553948A (en) * | 1994-02-03 | 1996-09-10 | Ntn Corporation | Static pressure gas bearing spindle assembly |
| JPH08331796A (en) * | 1995-06-02 | 1996-12-13 | Matsushita Electric Ind Co Ltd | Motor with fluid bearing |
| JPH11264410A (en) * | 1998-01-13 | 1999-09-28 | Matsushita Electric Ind Co Ltd | Fluid bearing device |
| JP2002155942A (en) * | 2000-11-17 | 2002-05-31 | Koyo Seiko Co Ltd | Sealed type thrust dynamic pressure bearing |
| CN1508452A (en) * | 2002-12-03 | 2004-06-30 | 松下电器产业株式会社 | Fluid bearing device and disc-rotation device using same |
-
2004
- 2004-07-29 JP JP2004222514A patent/JP2006038179A/en active Pending
-
2005
- 2005-07-29 CN CNB2005100885237A patent/CN100356074C/en not_active Expired - Fee Related
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH06137320A (en) * | 1992-10-29 | 1994-05-17 | Nippon Seiko Kk | Dynamic pressure fluid bearing device |
| US5553948A (en) * | 1994-02-03 | 1996-09-10 | Ntn Corporation | Static pressure gas bearing spindle assembly |
| JPH07310747A (en) * | 1994-05-13 | 1995-11-28 | Nippon Ferrofluidics Kk | Dynamic pressure bearing device |
| JPH08331796A (en) * | 1995-06-02 | 1996-12-13 | Matsushita Electric Ind Co Ltd | Motor with fluid bearing |
| JPH11264410A (en) * | 1998-01-13 | 1999-09-28 | Matsushita Electric Ind Co Ltd | Fluid bearing device |
| JP2002155942A (en) * | 2000-11-17 | 2002-05-31 | Koyo Seiko Co Ltd | Sealed type thrust dynamic pressure bearing |
| CN1508452A (en) * | 2002-12-03 | 2004-06-30 | 松下电器产业株式会社 | Fluid bearing device and disc-rotation device using same |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2006038179A (en) | 2006-02-09 |
| CN1727707A (en) | 2006-02-01 |
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