CN1957408A - Fluid dynamic pressure bearing, spindle motor and storage disk drive device having the fluid dynamic pressure bearing and a method of manufacturing thereof - Google Patents
Fluid dynamic pressure bearing, spindle motor and storage disk drive device having the fluid dynamic pressure bearing and a method of manufacturing thereof Download PDFInfo
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- CN1957408A CN1957408A CN 200580016141 CN200580016141A CN1957408A CN 1957408 A CN1957408 A CN 1957408A CN 200580016141 CN200580016141 CN 200580016141 CN 200580016141 A CN200580016141 A CN 200580016141A CN 1957408 A CN1957408 A CN 1957408A
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Abstract
A fluid dynamic bearing having a shaft and a bearing sleeve rotatably supported relative to each other. At least one of the shaft and the bearing sleeve is made of steel or stainless steel made of by weight C: 0.6~1.20%; Si: 1.0% or less; Mn: 1.0% or less; Cr: 10.5~18.0%; Mo: 1.0% or less; S.: 0.03% or less; and Fe. The dynamic pressure bearing surface is formed by ridges remaining in between multiple dynamic pressure grooves formed by electrochemical machining.
Description
The application requires all right of priority rights of Japanese patent application No.2004-151109 (unsettled) that submitted on May 20th, 2004 and the Japanese patent application No.2005-103496 (unsettled) that submitted on March 31st, 2005.
Technical field
The present invention relates to be used for the fluid dynamic pressure bearing (also being commonly referred to as " hydrodynamic bearing ") that uses in the Spindle Motor of storage disk drive device.The invention still further relates to the manufacture method of these hydrodynamic bearings.More specifically, the present invention relates to the technological improvement of dynamic pressure performance of the hydrodynamic bearing of steel or stainless steel material.In addition, the present invention relates to the remarkable improvement of the bearing surface structure of accurate and high precision hydrodynamic bearing.In addition, the present invention relates to use Spindle Motor and the storage disk drive device that improves hydrodynamic bearing.
Background technology
Figure 17 shows an example of existing hydrodynamic bearing.Fluid dynamic pressure bearing equipment shown in this Fig has the turning axle 2 in the cylindrical hole that rotatably is supported on bearing sleeve 1.Thereby the bottom opening of the cylindrical hole of bearing sleeve 1 is sealed turning axle in bearing sleeve by anti-plate 3 sealings.Disc-shaped thrust plate 4 is fixed on the bottom of turning axle 2.A plurality of arc spiral fashions or herringbone shape dynamic pressure grooves (not shown) be formed on the thrust plate 4 with anti-plate 3 opposing lower surface on.And a plurality of dynamic pressure grooves (not shown)s are formed on similarly and are formed in the bearing sleeve and are higher than on the lower surface of step of thrust plate.And a plurality of spiral fashions or herringbone shape dynamic pressure grooves 18 are formed on the inner peripheral surface of bearing sleeve 1.Be formed at together with the solid bearing sleeve of anti-plate with together with being filled with lubricating oil in the bearing slit between the turning axle of thrust plate.
In recent years, hard disk drive (typical disk drive memory device) miniaturization, weight saving and the thinner trend of profile have sharply been required.Meanwhile, because hard disc storage capacity increases, the requirement of increase is arranged for increasing superficial density.Therefore, widely used hydrodynamic bearing has been carried out a large amount of research, this makes the application in the Spindle Motor of hydrodynamic bearing in hard disk drive significantly increase.Research concentrates on and forms more accurate and high-precision dynamic pressure grooves this respect so that accurately and effectively produce dynamic pressure.
Galvanochemistry processing is known as the method that is used to form dynamic pressure grooves at present.Yet, when the bearing sleeve that this method is used for being made by the sulfur-bearing free-machining alloy steel with well processed character, be difficult to use galvanochemistry to be processed and decompose (dissolve) and form a plurality of dynamic pressure grooves.The vpg connection that also is difficult to the spine that stays between dynamic pressure grooves obtains the accuracy and the high precision of extend of hope.Fig. 3 A shows, and when observing each dynamic pressure grooves surperficial on xsect, connecting the top 22 of each spine and the bight 24 of inclined wall 23 is spherings.This is the result that unevenness caused who comprises during the galvanochemistry processing between the decomposition characteristics of the decomposition characteristics of sulphide inculsion (being included in the sulfur-bearing free-machining alloy steel) of easy cutting composition and Fe (it is the principal ingredient of metal).In addition, the sphering in bight is to be exposed to the result that lip-deep sulphide inculsion that galvanochemistry processes comes off (dislodging) and breaks.
Importantly optimize dynamic pressure efficient (dynamic pressure/axially loss), so that more accurate and form dynamic pressure effectively.In Fig. 3 B, preferably spine-groove ratio is as follows:
(1) (the dynamic pressure grooves width, Bv)/(top width, B1)=1.0～1.3
In addition, also preferably the groove depth ratio is as follows:
(2) (from the distance of dynamic pressure grooves facing surfaces to trench bottom, h0)/(groove depth, hg)=2.1～2.3
Yet be difficult to for above-mentioned reasons in batch process, realize (1) and (2).
Because the unsolvability of sulphide inculsion has also caused other problem with coming off.The surface of repairing by grinding and the surface of repair by galvanochemistry processing be owing to come off and unsolvability exists the problem of irregular surface, thereby worsened surfaceness.On being exposed to finished surface or the sulphide inculsion that comes off from the surface forms and when being stuck between axis body and the parts of bearings, also caused other problem.
Owing to exist these problems, bearing rigidity in the hydrodynamic bearing reduces and the axial torque loss increases so that be used for running accuracy and decline in serviceable life, power consumption and increase start-up time of the Spindle Motor of storage disk drive device, the prominent question that has caused storage disk drive device is especially in its miniaturization with more under the trend of thin contour.
For example utilized that disclosed method prevents coming off of sulphide inculsion among the Jap.P. prospectus 2001-298899 and Jap.P. prospectus 2002-119584.Above-mentioned document suggestion utilizes bronsted lowry acids and bases bronsted lowry to remove sulphide inculsion after processing component.Yet these removal methods are unfavorable for the reduction of manufacturing cost, because increased the complicacy of manufacturing process.The processing of bronsted lowry acids and bases bronsted lowry is dangerous and brings harm to environment.In addition, disclosed method is not providing any solution aspect accuracy of hydrodynamic bearing surface structure and the high-precision improvement.In addition, use bronsted lowry acids and bases bronsted lowry to remove sulphide inculsion and also finally decomposed matrix, and have the defective in the bight of sphering spine.
Summary of the invention
Consider above-mentioned prior art problems, a target of the present invention provides a kind of hydrodynamic bearing, and it optimizes dynamic pressure efficient by the accurate and high-precision surface structure with very little surfaceness.Another target of the present invention is to prevent coming off of sulphide inculsion, make and after long-time, can keep high bearing rigidity and little axial torque loss always, complex steps in need not simultaneously to make has been avoided handling the danger of bronsted lowry acids and bases bronsted lowry, and has been reduced the harm for environment.
One main aspect, the present invention is a kind of flow dynamic bearing, it has axle and the bearing sleeve that rotatably supports relative to each other.According to the present invention, at least one in axle and the bearing sleeve made by the steel or stainless steel that comprises following percentage by weight composition: C:0.6-1.20%; Si:1.0% or still less; Mn:1.0% or still less; Cr:10.5-18.0%; Mo:1.0% or still less; S:0.03% or still less; And Fe.The spine that is retained between a plurality of dynamic pressure grooves that are processed to form by galvanochemistry comprises the dynamic pressure bearing surface.
Since have in the present invention sulfur content in the material of parts of dynamic pressure grooves remain on 0.03% or still less and sulphide inculsion considerably less, just do not have unevenness in the surface by cutting down or the surface of repairing by galvanochemistry processing.Therefore, not only can improve surfaceness and be easy to accurately be shaped accurately the dynamic pressure bearing surface, but also keep the fluid dynamic pressure bearing of stability and high bearing rigidity and keep low axial torque loss after long-time use is provided.In addition, need not to relate to that unsound work has the parts on dynamic pressure bearing surface with cleaning on the complexity of using acid or alkali, the harmful and environment, thereby help making.In addition, thus the present invention does not exist when removing sulphide inculsion in the prior art and to use acid or matrix that alkali caused to decompose the problem in the bight of sphering spine.
Above aspect, advantage and characteristics only are representative embodiment.Be to be understood that they are not considered as is to restriction of the present invention defined by the claims.In description below, accompanying drawing and the claim, other characteristics of the present invention and advantage will become clearly.
Description of drawings
The present invention illustrates by means of nonrestrictive example, the same or corresponding parts of same in the accompanying drawings designated, and wherein:
Fig. 1 shows the cross-sectional view according to an embodiment of hydrodynamic bearing of the present invention.
Fig. 2 shows the planimetric map that is used for end plate embodiment illustrated in fig. 1 13.
Fig. 3 A and 3B show the local cross-sectional view that dynamic pressure produces groove.
Fig. 4 A shows the profile that the dynamic pressure of making according to first embodiment of the invention produces groove.
Fig. 4 B shows the profile that the dynamic pressure of making according to second embodiment of the invention produces groove.
Fig. 4 C shows the profile that the dynamic pressure of making according to reference examples produces groove.
Fig. 5 A shows the photo that the dynamic pressure of making according to first embodiment of the invention produces groove.
Fig. 5 B shows the photo that the dynamic pressure of making according to second embodiment of the invention produces groove.
Fig. 5 C shows the photo that the dynamic pressure of making according to reference examples produces groove.
Fig. 6 A and 6B show the enlarged photograph of the dynamic pressure generation groove of first embodiment of the invention.
Fig. 7 A and 7B show the enlarged photograph of the dynamic pressure generation groove of second embodiment of the invention.
Fig. 8 A and 8B show the enlarged photograph of the dynamic pressure generation groove of reference examples.
The dynamic pressure that Fig. 9 A and 9B show reference examples and second embodiment of the invention respectively produces the electron micrograph of the end face spine of groove.
Figure 10 shows the synoptic diagram of sulfide and lead composition situation in the galvanochemistry processing.
Figure 11 shows the cross-sectional view according to the Spindle Motor of one embodiment of the invention structure.
Figure 12 shows the cross-sectional view of hard disk drive device constructed according to the invention.
Figure 13 shows the cross-sectional view according to the Spindle Motor of another embodiment of the present invention structure.
Figure 14 shows the photo according to third embodiment of the invention galvanochemistry first being processed specimen surface situation.Particularly, (begin) wherein to show DD material tempering photo, the photo after the tempering of DD material, the photo of SF20T material (starting material) and the photo of DHS-1 material (starting material) before clockwise from the photo upper left corner.
Figure 15 A shows the profile of the dynamic pressure generation groove of the 3rd embodiment that utilizes the DD material.
Figure 15 B shows the profile (reference examples) that the dynamic pressure of utilizing the SF20T material produces groove.
Figure 15 C shows the profile (reference examples) that the dynamic pressure of utilizing the DHS-1 material produces groove.
Figure 16 A shows the electron micrograph on the amplification surface of the boundary vicinity between the bottom of the top of the spine made from the DD material according to the 3rd embodiment and groove.
Figure 16 B shows the electron micrograph on the amplification surface of the boundary vicinity between the bottom of the top of the spine made from SF20T and groove.
Figure 16 C shows the electron micrograph on the amplification surface of the boundary vicinity between the bottom of the top of the spine made from DHS-1 and groove.
Figure 17 shows the cross-sectional view of an example of the hydrodynamic bearing of prior art.
Embodiment
Be description of the preferred embodiment of the present invention below.In the present invention, at least one preferably has percentage by weight and is lower than 0.001% Pb in axle or the parts of bearings.Its reason is as follows.
Although discussed owing to the unsolvability of sulphide inculsion and the caused problem that comes off, decomposable composition also can cause significant problem.Because the easy degree difference of dissimilar metal elutions has caused process velocity to occur changing in the galvanochemistry processing, therefore just can not remove material equably.The material quantity that electromachining is removed is calculated in the utilization Faraday's law shown in 1 as the following formula.
Formula 1:
M＝ηZIt
Wherein:
M is the material quantity of removing by electrolysis, in gram;
Z is electrochemical equivalent (g/C);
I is by electric current (A);
T is by time (s);
η is a current efficiency.
Formula 2 is used for calculating the volume of the metal material of removing by galvanochemistry processing, and density is ρ.
Formula 2:
V＝M/ρ
Therefore:
V＝ηZIt/ρ
Therefore, the material volume that time per unit is removed, i.e. the speed of galvanochemistry processing is by 3 expressions of following formula.In formula 3, K=Z/ ρ is the electrolysis constant, and volumetric removal rate is directly proportional with the electrolysis constant when machined parameters (by electric current and current efficiency) is constant.
Formula 3:
v＝V/t
v＝ηZI/ρ
v＝ηKI
Table 1 shows the electrolysis constant that is used for the contained main chemical elements of stainless steel.The electrolysis constant is big more, and the volumetric removal rate in the galvanochemistry processing is high more.Shown in following table 1, the lead in the metal (Pb) composition has maximum electrolysis constant.The decomposition of lead composition and removal are faster than other metal.On the contrary, the sulphur of negative charge (S) composition does not decompose, and when matrix decomposed around, the sulphur composition came off and removes.The process velocity of lead composition is the twice of other metal or bigger, and therefore lead composition is processed quickly, stays pit in the surface that it has decomposed.On the other hand, adeciduate sulphur composition stays projection from the teeth outwards, and its form is the sulphide inculsion outstanding from the surface.Figure 10 is the synoptic diagram that this situation is shown.As shown in figure 10, after galvanochemistry processing, pit occurs, caused the surfaceness of machined surface to worsen on the surface that the galvanochemistry first being processed has been flattened.In a preferred embodiment of the invention, the percentage by weight of reason lead content is less than 0.001% for this reason, and this is to guarantee that surfaceness is one of Ra0.1 μ m or littler necessary condition.
Table 1
| Element term | Fe | C | Si | Mn | P | S | Cr | Mo | V | Pb |
| The electrolysis constant | Divalence: 0.037 trivalent: 0.025 | 0.124 | 0.042 | Divalence: 0.038 trivalent: 0.026 tetravalence: 0.019 | Divalence: 0.088 trivalent: 0.058 sexavalence: 0.029 | Annotate 1 | Divalence: 0.038 trivalent: 0.025 | Divalence: 0.049 tetravalence: 0.024 | Divalence: 0.045 trivalent: 0.030 sexavalence: 0.015 | 0.095 |
Annotate 1: in galvanochemistry processing, do not decompose, because sulphur has negative charge.
Then, in the hydrodynamic bearing of axle that has relative to each other rotatably support and parts of bearings, the invention provides the manufacture method of hydrodynamic bearing, at least one is made by steel or stainless steel in its axis and the parts of bearings, and described steel or stainless steel comprises (percentage by weight): C:0.6-1.20%; Si:1.0% or still less; Mn:1.0% or still less; Cr:10.5-18.0%; Mo:1.0% or still less; S:0.03% or still less; Pb: be less than 0.001%, and Fe.In steel, the diameter of eutectic carbon granule is 10 μ m or littler, and steel or stainless steel comprises tempering and annealing through heat-treated.Galvanochemistry processing is carried out after polishing so that end face spine still keeps intact during at the bearing surface that is processed to form by galvanochemistry between a plurality of dynamic pressure grooves.
Confirmed that by the research that the inventor carries out the surface is good more in the surfaceness of first being processed, the surfaceness of finished surface after galvanochemistry processing is also good more.Exist very small amount of sulphide inculsion in the steel or stainless steel that manufacture method limited by hydrodynamic bearing of the present invention, because these steel have the eutectic carbide of minor diameter, and sulfur content is limited in low-down level.In addition, because almost there is not lead, handle by hardening heat, it is more tiny and more even that metal construction just becomes.Thereby, just prevented during grinding after thermal treatment and the polishing material tear or some composition comes off from material surface, and improve the surfaceness of galvanochemistry first being processed significantly.For example, the surfaceness of the end face spine that obtains after the galvanochemistry processing is Ra 0.1 μ m or littler.
When observing the xsect of resulting bearing surface, be clear that very resulting dynamic pressure produces groove and formed by straight basically end face spine, straight basically inclined wall and straight basically bottom.End face spine is connected by roughly arc bight with inclined wall.The bight with direction that straight basically end face spine parallels on length, promptly the length M among Fig. 3 B is preferably 20 μ m or littler, and the bight with direction that straight basically inclined wall parallels on length, be the length L among Fig. 3 B, be preferably 1.0 μ m or littler
In addition, when on xsect, observing bearing surface, the length of each inclined wall is preferably the 75-90% of a dummy line segment length, and this virtual line segment obtains by using with the tangent straight line of flat top spine with the tangent straight line of tangent parallel lines cutting of the minimum point of bottom surface slot part and inclined wall.
In a preferred embodiment of the invention, the surfaceness of end face spine is Ra1.0 μ m or littler.In addition, the change in depth of dynamic pressure generation groove is preferably 0.4 μ m or littler.
The suitable structure of hydrodynamic bearing of the present invention is described with reference to the accompanying drawings.
Fig. 1 is the cross-sectional view of an embodiment of hydrodynamic bearing of the present invention.As shown in Figure 1, hydrodynamic bearing has axle 12, cylindrical housings 10 and the tubulose bearing sleeve 11 that is fit into cylindrical housings 10 along cylindrical form interior surface 17.Axle 12 and bearing sleeve 11 rotatably support relative to each other.Thrust plate 14 is fixedly secured on the end (bottom among Fig. 1) of axle 12.The bottom of disc shaped end plate 13 closure casings 10 is so that thrust plate 14 is positioned between the bottom surface 15 of the end face 16 of end plate and bearing sleeve 11.
The outer peripheral face 19 of radial dynamic pressure bearing surface 11a, 11b and axle 12 relatively is formed on the inner peripheral surface 18 of bearing sleeve 11.Transverse bearing surface 11a and 11b bear the load that the footpath makes progress.The axial hydrodynamic mechanical axis holds bottom surface 15 that surface 31 and the end face 30 of thrust plate 14 relatively be formed at bearing sleeve 11 and sentences load on producing dynamic pressure and bearing axially.Other axial hydrodynamic mechanical axis holds end face 16 that surface 20 and the bottom surface 32 of thrust plate 14 relatively be formed at end plate 13 and sentences other load on producing other dynamic pressure and bearing axially.11a, 11b, 20 and 31 are not necessarily limited to lambdoid dynamic pressure grooves on these dynamic pressure bearing surfaces.They can be the dynamic pressure grooves that forms with spirality, arc, linear or other shape.Be formed at dynamic pressure bearing surface 11a, 11b, 20 and 31 and the apparent surface between micro gap be filled with lubricating oil.
The material that is used for bearing sleeve 11 and end plate 13 is a steel or stainless steel, and described steel or stainless steel comprises (percentage by weight): C:0.6-1.2%; Si:1.0% or still less; Mn:1.0% or still less; Cr:10.5-18.0%; Mo:1.0% or still less; S:0.03% or still less; And Fe.After material is by thermal treatment and polishing, is processed to form dynamic pressure by galvanochemistry and produces bearing surface so that each surface comprises a plurality of end face spines between a plurality of herringbone dynamic pressure grooves, for example as shown in Figure 2.
Shown in the cross-sectional view among Fig. 3, end face spine 22 forms basically straightly.Each dynamic pressure grooves 21 has two straight basically inclined walls 23 and a bottom.Inclined wall 23 is connected by roughly arc bight 24 with end face spine 22.Bight 24 with direction that straight pre-face spine 22 basically parallels on length M be 20 μ m or littler.Bight 24 with direction that straight basically inclined wall 23 parallels on length L be 1.0 μ m or littler.The length B of each inclined wall 23 is preferably the 75-90% of a virtual line segment A length, and this virtual line segment is tangent and obtain with the tangent straight line of the tangent parallel lines cutting of the lowermost portion of the bottom surface of dynamic pressure grooves and inclined wall 23 with straight end face spine 22 by using.
Utilize galvanochemistry processing to form dynamic pressure grooves on the bearing surface of correct grinding, so that the surfaceness of end face spine is Ra0.1 μ m or littler, and the change in depth of the dynamic pressure grooves between the groove is 0.4 μ m or littler.Like this, just obtained to have the dynamic pressure performance of expectation efficient and the hydrodynamic bearing of stable long-term reliability.
Have considerably less exposing or outstanding sulphide inculsion according to said method with the bearing sleeve 11 of steel or stainless steel manufacturing and end plate 13 from finished surface.Therefore, need not to utilize acid or alkali to remove this being mingled with, thereby make and to reduce manufacturing cost and avoid harm and the environmental hazard relevant with acid or alkali.In addition, heat treated temperature is chosen as and makes parts of bearings be tempered to high rigidity.Therefore, parts of bearings is unlikely during assembly process defective occurs owing to swiping or being out of shape.These parts also unlikely owing to the startup that when bearing apparatus uses, stands, stop, vibrating or impact the wearing and tearing that load caused that produce and impaired.And the defective of rounded corner this problem can not occur in above-mentioned fluid dynamic pressure bearing equipment with the technology of bronsted lowry acids and bases bronsted lowry removal sulphide inculsion though prior art exists.
Figure 11 is the cross-sectional view of schematic structure that the Spindle Motor 200 of the hydrodynamic bearing A that utilizes heat-treatment protocol shown in Figure 1 is shown, and described hydrodynamic bearing is heat-treated according to the operation described in the following embodiment 2.Hydrodynamic bearing A makes as the following examples 2.Notice that Spindle Motor 200 is not limited to the hydrodynamic bearing of embodiment 2, and can be applied to a lot of bearing embodiment within the scope of the invention.
Axially towards threaded hole (not shown) is formed at the center of the upper surface of axle 12, and utilizes this threaded hole sectional fixture (not shown) with Fixed disk.Flexible PCB 240 is installed on the bottom surface of base portion 210, and by Control current is supplied to stator 220 from the output terminal of this flexible PCB 240, the rotor assembly that comprises rotor magnet 232 and axle 12 is with respect to stator 220 rotations.
Have in the Spindle Motor 200 of the hydrodynamic bearing A of embodiment 2, when axle rotates, by thrust dynamic pressure generation the axial hydrodynamic power that groove produced of balance on above-below direction by hydrodynamic bearing A, rotor 230 is maintained at settling position and can float or sink.
In the Spindle Motor 200 of the foregoing description, high-precision bearing surface structure makes may obtain high bearing rigidity, although it is small-sized and profile is very thin.And preferred construction has caused low axial torque loss, and this has just caused low power consumption.In addition, can reduce manufacturing cost.In addition, can also keep reliability after using for a long time, because the bearing surface of Spindle Motor 200 has considerably less exposure or outstanding sulphide inculsion and provides high-grade hardness by suitable thermal treatment.
Figure 12 utilizes the cross-sectional view of the schematic structure of the hard disk drive device of Spindle Motor 200 (storage disk drive device) 300 as shown in figure 11.Lid 301 provides the inside of the base portion 210 that seals Spindle Motor 200 shown in Figure 1 in this hard disk drive device 300, form the cleaning chamber with few dirt or dust.The housing of hard disk drive device 300 comprises and covers 301 and base portion 210.Therefore, base portion 210 constitutes the part of Spindle Motors 200 and as the part of the housing of hard disk drive device 300.Like this, the critical piece of Spindle Motor (comprising Spindle Motor stator and rotor) just is contained in the housing of hard disk drive device 300.
One deck hard disk (memory disk) 304 is installed on the outer peripheral face of rotor hub 231.Come fastening clips by sectional fixture 303 and by means of the threaded hole that centrepin 305 is threaded into the turning axle upper end, hard disk 304 is fixed to rotor hub 231.Therefore, hard disk 304 rotates as a global facility with rotor hub 231.In the present embodiment, a hard disk 304 is installed on the rotor hub 231, yet, can be installed in the not restriction of number of the hard disk on the rotor hub.
Hard disk drive device 300 is provided with magnetic head 306, and it writes hard disk 304 with data and from hard disk 304 reading of data.Magnetic head is supported by arm 307 and is provided with voice coil motor 308, and voice coil motor 308 moves to desired location with magnetic head 306 and arm 307.The magnet 310 that voice coil motor 308 has coil 309 and relatively arranges with coil 309.
Thereby, by using Spindle Motor as shown in figure 11, the hard disk drive device 300 of present embodiment provides high bearing rigidity owing to used high-precision bearing surface structure in little and thin profile, and little axial torque loss and lower power consumption is provided, but also reduced manufacturing cost.Although this embodiment of the present invention is described as being applied to hard disk drive device, it can also be applied to have storage disk drive device optical head, that handle CD, DVD etc.
In addition, although previous embodiment has been provided by an example of the storage disk drive device 300 of the Spindle Motor 200 that has turning axle type hydrodynamic bearing A and provide for this hydrodynamic bearing A, hydrodynamic bearing of the present invention also can be applicable to stationary shaft type Spindle Motor.
Figure 13 shows the critical piece of the stationary shaft type Spindle Motor that is used for hard disk drive device 301.In the following description, Spindle Motor has and the identical structural detail of structural detail shown in Spindle Motor 200 and Figure 11 and 12, therefore omits the description for same reference numerals.As shown in figure 13, the axle 12 of hydrodynamic bearing A is pressed-fit into the mounting hole 211 that is formed in the base portion 210.The cylindrical housings 10 of hydrodynamic bearing A is pressed-fit into the mounting hole 231a that is formed in the rotor hub 231.Anchor clamps 303 are installed on the end face of rotor hub 231 by means of centrepin 305, and hard disk 304 is fastened on the rotor hub 231 by anchor clamps 303.The hard disk drive device 301 of Gou Chenging hard disk drive device 300 is as shown in figure 12 operated like that and is had an identical effect like this.Notice, in the present embodiment, rotor be arranged as external form same as shown in Figure 12, but in type also be possible.
Embodiment 1
Produce martensitic stain less steel disc blank by turning, it comprises (percentage by weight): C:0.6-1.20%; Si:1.0% or still less; Mn:1.0% or still less; Cr:10.5-18.0%; Mo:1.0% or still less; S:0.03% or still less; And Fe.Then, on both sides and neighboring, polish after the blank, carry out galvanochemistry processing to form dynamic pressure bearing surface 20 on a side of blank, as shown in Figure 2, described dynamic pressure bearing surface 20 comprises that the herringbone dynamic pressure produces groove 21 and is retained in end face spine 22 between the groove.So, just produced end plate 13 with motive bearing surface 20.
Similarly, turning goes out the tubular blank of aforementioned martensitic stain less steel, then at two ends, outer peripheral face and inner peripheral surface polish.Then, carry out galvanochemistry processing to form dynamic pressure bearing surface 20 on a side of this blank, as shown in Figure 2, described dynamic pressure bearing surface 20 comprises a plurality of herringbone dynamic pressure grooves 21 and is retained in end face spine 22 between the groove.And, on the part inner peripheral surface of tubular blank, carrying out galvanochemistry processing forming dynamic pressure bearing surface 11a and 11b (referring to Fig. 1), it comprises a plurality of herringbone dynamic pressure grooves similarly and is retained in flat top spine between the groove.
Embodiment 2
According to a second embodiment of the present invention, at first under the condition identical, produce end plate and bearing sleeve with embodiment 1.Yet, after turning, at polishing and galvanochemistry turned blank before forming dynamic pressure generation groove 21 blank hardened and to be annealed to the Rockwell's hardness of HRC58-62.
Reference examples
Utilize the foregoing description 1 described technology, use sulfur-bearing free-machining alloy steel (SUS430F) to produce end plate and bearing sleeve, the composition of described alloy steel is (percentage by weight): C:0.05% or still less; Si:1.0% or still less; Mn:2.0% or still less, Cr:19～21%; Mo1.5～2.5%; P:0.05%; S:0.1 0%-0.15%; Pb:0.1-0.3%; Surplus is Fe and unavoidable impurities.
Assessment
1. overall the observation
Fig. 5 A-5C is the photo that the dynamic pressure bearing surface of embodiment 1,2 and reference examples is shown.Fig. 6 A, Fig. 7 A and Fig. 8 A are the zoomed-in views that these dynamic pressure produce groove.Also have, Fig. 6 B, Fig. 7 B and Fig. 8 B are the enlarged photographs of the oblique view on these dynamic pressure surfaces.Photo among Fig. 6,7 and 8 is respectively corresponding to embodiment 1,2 and reference examples.
Fig. 9 A and 9B are respectively the electronic photos that is formed at the end face spine on the dynamic pressure bearing surface on the end face of bearing sleeve among reference examples and the embodiment 2.
2. dynamic pressure grooves profile
Utilize surface measurement equipment (the surperficial survey meter that Ryoka Systems Inc. makes), on the hydrodynamic bearing surface 20 of embodiment 1,2 and reference examples, produce the groove direction and vertically intercept profile with dynamic pressure.The result is respectively shown in Fig. 4 A-4C.
3. in Fig. 4 A-4C, measure the sphering size in the bight that connects end face spine and inclined wall, and the maximum sphering size on horizontal direction (M) and the vertical direction (L) among Fig. 3 B.
4. surfaceness
The surface roughness Ra of the surface roughness Ra of measurement end face spine and the bottom of dynamic pressure grooves, and the variation between the minimum and maximum value of calculating dynamic pressure generation groove depth.
5. the shape of dynamic pressure grooves etc.
Observe shape, the shape in bight and the bottom degree of irregularity of dynamic pressure grooves of dynamic pressure grooves.The result is shown in the table 2.
6. the inclined wall of dynamic pressure grooves.
Calculate straight portion and the ratio between the whole length, the i.e. B/A (%) among Fig. 3 A of each inclined side of dynamic pressure grooves.The result is shown in the table 3.
Table 2
| Project | Embodiment 1 | Embodiment 2 | Reference examples |
| The surfaceness of end face spine (Ra μ m) | 0.07 | 0.05 | 0.11 |
| Maximum sphering size, end face spine direction (μ m) | 17 | 17 | 37 |
| Maximum sphering size, groove depth direction (μ m) | 0.7 | 1.0 | 1.3 |
| The surfaceness (Ra μ m) of dynamic pressure grooves bottom | 0.10 | 0.15 | 0.20 |
| The change in depth of dynamic pressure grooves (μ m) | 0.23 | 0.30 | 0.42 |
| The shape of dynamic pressure grooves | Bias free | Deviation | Deviation |
| Dynamic pressure grooves bight arc | Little arc | Little arc | Big arc |
| The scrambling situation of trench bottom | No scrambling | No scrambling | Scrambling |
Table 3
| Embodiment 1 | Embodiment 2 | Reference examples | ||||
| The left bank surface | The right bank surface | The left bank surface | The right bank surface | The left bank surface | The right bank surface | |
| Position 1 | 83.0 | 77.9 | 73.3 | 76.7 | 69.0 | 68.9 |
| Position 2 | 92.0 | 76.8 | 73.5 | 69.9 | 77.0 | 70.6 |
| Position 3 | 85.6 | 80.9 | 64.4 | 78.6 | 83.3 | 67.6 |
| Position 4 | 80.0 | 79.1 | 83.2 | 93.8 | 70.4 | 68.1 |
| Mean value | 85.2 | 78.7 | 73.6 | 79.7 | 74.9 | 68.8 |
| Population mean | 81.9 | 76.7 | 71.9 | |||
Clearly, in embodiment 1, as shown in Figure 6A, and in embodiment 2, shown in Fig. 7 A, the bottom of the dynamic pressure grooves that is processed to form by galvanochemistry according to the present invention is flat and has and almost do not have irregular shape from Fig. 6 A and Fig. 7 A.This polycrystalline substance as lubricating oil flow path in the fluid bearing equipment has reduced flow resistance and turbulent flow, thereby makes that can reduce axial torque loses and produce effectively dynamic pressure.On the other hand, have the scrambling of significance degree shown in Fig. 8 A (reference examples) in the shape, and in as fluid bearing equipment, will cause flow resistance and turbulization easily like this during the stream of lubricating oil, and tend to increase the axial torque loss.
Fig. 9 A and 9B are respectively the electronic photos of the end face spine of reference examples and embodiment 2.Shown in Fig. 9 A, exist bigger sulphide inculsion (external diameter surpasses 10 μ m), this can cause staying projection or coming off, and stays pit from the teeth outwards.On the other hand, in Fig. 9 B, have only considerably less little sulphide inculsion (external diameter is less than 1 μ m), and matrix be very thin crystal grain and be uniformly so that no matter be size or shape all without a doubt.The numerical value of the dynamic pressure grooves bottom surface roughness shown in these observationss and the table 2 is interrelated.
From Fig. 4, clearly,, exist suitable scrambling in the reference examples although all there is not scrambling in the bottom of the dynamic pressure grooves of embodiment 1 and 2.As mentioned above, the scrambling in the lubricating oil flow path is easy to cause flow resistance or turbulent flow, and can cause the increase of axial torque loss.And, the very little and formation sharp edges in the bight of sphering in embodiment 1 and 2, and the bight of sphering is very big in reference examples.So by utilizing the present invention, the flat top spine of dynamic pressure grooves is formed and makes them very near its maximum possible size, and is as shown in table 3, between spine and groove, obtain the ratio of wishing simultaneously.On the other hand, in reference examples, so end face spine small-sized and, the ratio between spine and the groove is significantly less than the numerical value of hope.Therefore, can determine to have obtained in the present invention to have the fabulous dynamic pressure grooves shape of wishing spine-groove ratio.
As shown in table 2, the surfaceness of the surfaceness of end face spine, bight (edge), dynamic pressure grooves bottom and the numerical value of dynamic pressure grooves change in depth are all very little.Therefore, the just accurate and high precision of the bearing surface structure after polishing and the galvanochemistry processing has obtained the spine-groove ratio of wishing, and has obtained to produce effectively the better hydrodynamic bearing of dynamic pressure.
Embodiment 3
Produce the stainless steel disc of three kinds of compositions shown in the table 4 and produce the herringbone dynamic pressure grooves to make disc sample shown in Figure 2 by galvanochemistry.Carry out the contrast of dynamic pressure grooves polishing.For simplicity, three kinds of stainless steels shown in the table 4 are called " DD ", " SF20T " and " DHS-1 ".The disc-shaped sample of being made by the DD material is hardened, polishes with the raising surfaceness, and carry out galvanochemistry processing then.DHS-1 and SF20T disc sample ground carry out galvanochemistry processing then.
Table 4
| Chemical constitution (unit: percentage by weight) | ||||||||||||
| Material | C | Si | Mn | P | S | Cr | Mo | V | Pb | Ti | O | |
| Standard value | DD | 0.60-0.75 | Maximum 1.00 | Maximum 1.00 | Maximum 0.030 | Maximum 0.020 | 11.50-13.50 | Maximum 0.30 | Maximum 0.15 | - | Maximum 15ppm | Maximum 15ppm |
| SF20T | Maximum 0.05 | Maximum 1.00 | Maximum 2.00 | Maximum 0.050 | Maximum 0.15 | 19.00-21.00 | 1.50-2.50 | - | - | - | - | |
| DHS-1 | Maximum 0.03 | Maximum 1.00 | Maximum 0.50 | Maximum 0.050 | Maximum 0.15 | 18.00-20.00 | 0.10-0.30 | - | - | - | - | |
| SUS440C | 0.95-1.20 | Maximum 1.00 | Maximum 1.00 | Maximum 0.060 | Maximum 0.03 | 16.00-18.00 | Maximum 0.75 | - | - | - | - | |
| Measured value | DD | * | * | * | * | 0.002 | * | * | * | 0.000 | * | * |
| SF20T | * | * | * | * | 0.185 | * | * | * | 0.089 | * | * | |
| DHS-1 | * | * | * | * | 0.204 | * | * | * | 0.091 | * | * | |
* there is not measured value
The DD material is a kind of martensitic stain less steel, it is because compare sulfur content with typical SUS440C martensite stainless steel material very little and eutectic carbide is small-sized, therefore has improved free-cutting machinability, and it can harden by tempering, and material is equal to the material of stipulating in the claim to a method of present patent application and the inventor Jap.P. No.3613534 identical with the application.DHS-1 and SF20T are ferritic stainless steels, and it has improved free-cutting machinability with can not comparing by the typical SUS430F ferrite stainless steel material that tempering is hardened.For reference, table 4 has comprised the standard value of the chemical constitution of SUS440C material.
As shown in table 4, to compare with the SF20T material with the DHS-1 material, the used DD material of present embodiment has low-down sulphur and lead content.SF20T material and DHS-1 material have about 0.2% sulfur content and about 0.09% lead content.Comparatively speaking, the DD material have almost nil lead content and low-down sulfur content (less than SF20T and DHS-1 material 1/10th).Therefore, after galvanochemistry processing, in fact do not have the sulphur composition to come off and almost do not have the decomposition of lead content, thereby make and on surfaceness, be improved from the surface.
Figure 14 is the x100 enlarged photograph doubly of various stainless steel surfaces.Clearly, the DD material has the fine grain metal construction of highest ranking after tempering from Figure 14.On the other hand, because SF20T and DHS-1 material can not harden by tempering, they just use with virgin state.Under original condition, can not load grinding stone and repair by polishing, consequently the blank surface of galvanochemistry first being processed can not be polished, and can not improve surfaceness in the galvanochemistry first being processed.
Figure 15 A-C shows the xsect (profile) of the herringbone dynamic pressure grooves that is formed on the disc-shaped sample.Figure 15 A shows the sample of being made by the DD material, and Figure 15 B shows the sample of being made by the SF20T material, and Figure 15 C shows the sample of being made by the DHS-1 material.From Figure 15 A-C, can find out, owing in the DD material sample being obtains to carry out after the fabulous surfaceness galvanochemistry to process and form dynamic pressure grooves after thermal treatment and polishing, so compare the sphering in bight with other samples very little, and confirm to have formed xsect accurately.In addition, the curve of qualification end face spine and slot part shape is compared more level and smooth with other samples, and the surfaceness on the final surface of expression is very good.
The reason that the sphering of dynamic pressure grooves shape is very little in the DD material is explained as follows:
(1) because lead or sulfur content are minimum, shape degenerates with regard to unlikely because giving prominence to and coming off of the preferential decomposition of lead composition or sulphur composition.
(2) because lead content is minimum, just suppress the tendency of the skirt selectivity elution between end face spine and the bottom, made the shape of dynamic pressure grooves have excellent precision.
In galvanochemistry processing, the current density that is located immediately in the elution zone under the conductive pattern surface of electrode tool is maximum and constant.Remove all the components of specimen surface, thereby form the bottom of dynamic pressure grooves corresponding to conductive pattern.In the conductive pattern of distance electrode instrument not elution zone enough far away, current density is near zero and do not have the decomposition of component, thereby stays end face spine on specimen surface.In elution with do not exist selectivity elution zone between the elution zone, wherein current density is reduced to zero from its maximal value.In selectivity elution zone, the composition with high electrolysis constant is by optionally elution.So we observe the phenomenon of bight, the border deterioration (sphering) between bottom and the end face spine.Because the lead content of DD material is actually zero, the sort of degree in other material can not appear in this phenomenon.
Figure 16 A-C is the electron micrograph that the various dynamic pressure grooves planimetric maps of sample are shown.Figure 16 A shows the sample of being made by the DD material, and Figure 16 B shows the sample of being made by the SF20T material, and Figure 16 C shows the sample of being made by the DHS-1 material.These photos are surperficial enlarged drawings of the boundary vicinity (being equivalent to the crooked V-shaped part among Fig. 6) between end face spine and the bottom.In all these photos, below the bottom of dynamic pressure grooves was illustrated in, above the surface of end face spine is illustrated in, and arc boundary member was illustrated in roughly centre.The surface of DD material sample does not demonstrate being mingled with or pit of occurring in other sample, and does not observe the remarkable deterioration of boundary member shape.Formed the dynamic pressure grooves of accurate shaping obviously.
Advantage of the present invention is as follows:
(1) because sulfur content very low (0.03% weight or still less), after galvanochemistry processing, come off the pit that stays owing to the sulphur composition or the projection that stays owing to sulphide inculsion with regard to seldom.
(2), just can suppress that the preferential decomposition owing to lead content forms pit during the galvanochemistry processing because lead content seldom (under 0.001% weight).
(3) owing to above-mentioned (1) and (2) has improved the finished lip-deep surfaceness quality of galvanochemistry.
(4) because a small amount of selectivity elution of (2) helps to improve the precision of dynamic pressure grooves structure.
(5) by at the tempering of galvanochemistry first being processed and this material of polishing to improve the lip-deep surfaceness that will be processed by galvanochemistry, improved the surfaceness after the galvanochemistry processing.
Reader for convenience, foregoing description concentrates on the representative example of the possible embodiment of institute, and this example has been instructed principle of the present invention and has been provided and has been regarded as carrying out optimal mode of the present invention.This description does not attempt to enumerate exhaustively all possible variation.Variation that other is not described or modification also are possible.For example,, the factor combination of different embodiment can be got up under many circumstances, perhaps the key element of embodiment described here and other are not had special modification of describing or set of variations altogether though described a plurality of optional embodiment.A lot of variation, modification and variations of not describing are all in the literal scope of claim, and other is equal to.
Claims (67)
1. hydrodynamic bearing comprises:
Spindle unit; With
Bearing sleeve parts, described bearing sleeve parts and described spindle unit rotatably support relative to each other;
Wherein at least one described parts is made by the steel that comprises following percentage by weight composition: C:0.6-1.20%; Si:1.0% or still less; Mn:1.0% or still less; Cr:10.5-18.0%; Mo:1.0% or still less; S:0.03% or still less; And Fe, and wherein said at least one described parts also comprise the hydrodynamic bearing surface, this hydrodynamic bearing surface has the hydrodynamic pressure that a plurality of galvanochemistry process and produces groove, and exists the end face spine of rising between described groove.
2. according to the hydrodynamic bearing of claim 1, wherein said steel is a stainless steel.
3. according to the hydrodynamic bearing of claim 1, wherein produce the galvanochemistry first being processed of groove, described steel is heat-treated in described hydrodynamic pressure.
4. according to the hydrodynamic bearing of claim 3, wherein produce the galvanochemistry first being processed of groove, described steel is polished in described hydrodynamic pressure.
5. according to the hydrodynamic bearing of claim 1, see on vertical xsect wherein that described hydrodynamic bearing surface also comprises straight basically end face spine, straight inclined wall and bottom basically.
6. according to the hydrodynamic bearing of claim 5, wherein said straight basically end face spine is connected to described straight basically inclined wall by arc basically part, and wherein the length of each described arc basically part on the direction parallel with described straight basically end face spine is 20 μ m or littler, and the length of each described arc basically part on the direction parallel with described straight basically inclined wall is 1.0 μ m or littler.
7. according to the hydrodynamic bearing of claim 5, wherein each described straight basically inclined wall has a length, described length is a 75%-90% with the tangent line segment length of described straight basically inclined wall, and this line segment is by being cut with the tangent straight line of described straight basically end face spine and with the tangent straight line of the minimum point of respective grooves.
8. according to the hydrodynamic bearing of claim 1, the surfaceness of the end face spine of wherein said rising is Ra 0.1 μ m or littler.
9. according to the hydrodynamic bearing of claim 1, the change in depth that wherein said pressure produces groove is 0.4 μ m or littler.
10. according to the hydrodynamic bearing of claim 1, wherein said steel comprises that also percentage by weight is 0.001% or Pb still less, as unavoidable impurities.
11. the Spindle Motor with hydrodynamic bearing, described Spindle Motor comprises:
The motor base portion;
Be fixedly secured to the bearing sleeve of described motor base portion;
Be fastened to the stator of described motor base portion;
Turning axle, described turning axle rotatably supports with respect to described bearing sleeve;
Be installed in the rotor hub on the described turning axle; With
Be fastened to the rotor magnet of described rotor hub, described rotor magnet produces rotating magnetic field with described stator;
In wherein said turning axle and the described bearing sleeve at least one made by the steel that comprises following percentage by weight composition: C:0.6-1.20%; Si:1.0% or still less; Mn:1.0% or still less; Cr:10.5-18.0%; Mo:1.0% or still less; S:0.03% or still less; And Fe, and in wherein said turning axle and the described bearing sleeve described at least one also comprise the hydrodynamic bearing surface, this hydrodynamic bearing surface has the hydrodynamic pressure generation groove that a plurality of galvanochemistry process, and exists the end face spine of rising between described groove.
12. according to the Spindle Motor of claim 11, wherein said steel is a stainless steel.
13. according to the Spindle Motor of claim 11, wherein produce the galvanochemistry first being processed of groove, described steel heat-treated in described hydrodynamic pressure.
14. according to the Spindle Motor of claim 13, wherein produce the galvanochemistry first being processed of groove, described steel polished in described hydrodynamic pressure.
15., see on vertical xsect wherein that described hydrodynamic bearing surface also comprises straight basically end face spine, straight inclined wall and bottom basically according to the Spindle Motor of claim 11.
16. Spindle Motor according to claim 15, wherein said straight basically end face spine is connected to described straight basically inclined wall by arc basically part, and wherein with the tangent line segment of described straight basically inclined wall by being cut with the tangent straight line of described straight basically end face spine and with the tangent straight line of the minimum point of respective grooves.
17. Spindle Motor according to claim 15, wherein each described straight basically inclined wall has a length, described length is a 75%-90% with the tangent line segment length of described straight basically inclined wall, and this line segment is by being cut with the tangent straight line of described straight basically end face spine and with the tangent straight line of the minimum point of respective grooves.
18. according to the Spindle Motor of claim 11, the surfaceness of the end face spine of wherein said rising is Ra 0.1 μ m or littler.
19. according to the Spindle Motor of claim 11, the change in depth that wherein said dynamic pressure produces groove is 0.4 μ m or littler.
20. according to the Spindle Motor of claim 11, wherein said steel comprises that also percentage by weight is 0.001% or Pb still less, as unavoidable impurities.
21. the Spindle Motor with hydrodynamic bearing, described Spindle Motor comprises:
The motor base portion;
Be installed in the stationary shaft on the described motor base portion;
Be fastened to the stator of described motor base portion;
The swivel bearing sleeve, described swivel bearing sleeve rotatably supports with respect to described stationary shaft;
Be installed in the rotor hub on the described swivel bearing sleeve; With
Be fastened to the rotor magnet of described rotor hub, described rotor magnet produces rotating magnetic field with described stator,
In wherein said stationary shaft and the described swivel bearing sleeve at least one made by the steel that comprises following percentage by weight composition: C:0.6-1.20%; Si:1.0% or still less; Mn:1.0% or still less; Cr:10.5-18.0%; Mo:1.0% or still less; S:0.03% or still less; And Fe, and in wherein said stationary shaft and the described swivel bearing sleeve described at least one also comprise the hydrodynamic bearing surface, this hydrodynamic bearing surface has the hydrodynamic pressure generation groove that a plurality of galvanochemistry process, and exists the end face spine of rising between described groove.
22. according to the Spindle Motor of claim 21, wherein said steel is a stainless steel.
23. according to the Spindle Motor of claim 21, wherein produce the galvanochemistry first being processed of groove, described steel heat-treated in described hydrodynamic pressure.
24. according to the Spindle Motor of claim 23, wherein produce the galvanochemistry first being processed of groove, described steel polished in described hydrodynamic pressure.
25., see on vertical xsect wherein that described hydrodynamic bearing surface also comprises straight basically end face spine, straight inclined wall and bottom basically according to the Spindle Motor of claim 21.
26. Spindle Motor according to claim 25, wherein said straight basically end face spine is connected to described straight basically inclined wall by arc basically part, and wherein with the tangent line segment of described straight basically inclined wall by being cut with the tangent straight line of described straight basically end face spine and with the tangent straight line of the minimum point of respective grooves.
27. Spindle Motor according to claim 25, wherein each described straight basically inclined wall has a length, described length is the 75%-90% with the tangent line segment length of described straight basically inclined wall, and this line segment is by being cut with the tangent straight line of described straight basically end face spine and with the tangent straight line of the minimum point of respective grooves.
28. according to the Spindle Motor of claim 21, the surfaceness of the end face spine of wherein said rising is Ra 0.1 μ m or littler.
29. according to the Spindle Motor of claim 21, the change in depth that wherein said pressure produces groove is 0.4 μ m or littler.
30. according to the Spindle Motor of claim 21, wherein said steel comprises that also percentage by weight is 0.001% or Pb still less, as unavoidable impurities.
31. a disk drive memory device comprises:
Spindle Motor with hydrodynamic bearing, described Spindle Motor comprises:
The motor base portion;
Be installed in the stationary shaft on the described motor base portion;
Be fastened to the stator of described motor base portion;
The swivel bearing sleeve, described swivel bearing sleeve rotatably supports with respect to described stationary shaft;
Be installed in the rotor hub on the described swivel bearing sleeve; With
Be fastened to the rotor magnet of described rotor hub, described rotor magnet produces rotating magnetic field with described stator;
Next stored disk of rotating on the described rotor hub of described Spindle Motor is installed; With
On described memory disk, carry out the data head of read/write operation,
In wherein said stationary shaft and the described swivel bearing sleeve at least one made by the steel that comprises following percentage by weight composition: C:0.6-1.20%; Si:1.0% or still less; Mn:1.0% or still less; Cr:10.5-18.0%; Mo:1.0% or still less; S:0.03% or still less; And Fe, and in wherein said stationary shaft and the described swivel bearing sleeve described at least one also comprise the hydrodynamic bearing surface, this hydrodynamic bearing surface has the hydrodynamic pressure generation groove that a plurality of galvanochemistry process, and exists the end face spine of rising between described groove.
32. a disk drive memory device comprises:
Spindle Motor with hydrodynamic bearing, described Spindle Motor comprises:
The motor base portion;
Be fixedly secured to the bearing sleeve of described motor base portion;
Be fastened to the stator of described motor base portion;
Turning axle, described turning axle rotatably supports with respect to described bearing sleeve;
Be installed in the rotor hub on the described turning axle; With
Be fastened to the rotor magnet of described rotor hub, described rotor magnet produces rotating magnetic field with described stator,
Next stored disk of rotating on the described rotor hub of described Spindle Motor is installed; With
On described memory disk, carry out the data head of read/write operation,
In wherein said turning axle and the described bearing sleeve at least one made by the steel that comprises following percentage by weight composition: C:0.6-1.20%; Si:1.0% or still less; Mn:1.0% or still less; Cr:10.5-18.0%; Mo:1.0% or still less; S:0.03% or still less; And Fe, and in wherein said turning axle and the described bearing sleeve described at least one also comprise the hydrodynamic bearing surface, this hydrodynamic bearing surface has the hydrodynamic pressure generation groove that a plurality of galvanochemistry process, and exists the end face spine of rising between described groove.
33. hydrodynamic bearing according to claim 1, also comprise the end plate that seals described bearing sleeve parts, described end plate has the hydrodynamic bearing surface, described hydrodynamic bearing surface has the hydrodynamic pressure generation groove that a plurality of galvanochemistry process, and has the end face spine of rising between the described groove.
34. according to the hydrodynamic bearing of claim 33, wherein said end plate is made by the steel that comprises following percentage by weight composition: C:0.6-1.20%; Si:1.0% or still less; Mn:1.0% or still less; Cr:10.5-18.0%; Mo:1.0% or still less; S:0.03% or still less; And Fe,
35. according to the hydrodynamic bearing of claim 34, wherein said steel comprises that also percentage by weight is 0.001% or Pb still less, as unavoidable impurities.
36. Spindle Motor according to claim 11, also comprise the end plate that seals described bearing sleeve parts, described end plate has the hydrodynamic bearing surface, described hydrodynamic bearing surface has the hydrodynamic pressure generation groove that a plurality of galvanochemistry process, and has the end face spine of rising between the described groove.
37. according to the Spindle Motor of claim 36, wherein said end plate is made by the steel that comprises following percentage by weight composition: C:0.6-1.20%; Si:1.0% or still less; Mn:1.0% or still less; Cr:10.5-18.0%; Mo:1.0% or still less; S:0.03% or still less; And Fe,
38. according to the Spindle Motor of claim 37, wherein said steel comprises that also percentage by weight is 0.001% or Pb still less, as unavoidable impurities.
39. Spindle Motor according to claim 21, also comprise the end plate that seals described bearing sleeve parts, described end plate has the hydrodynamic bearing surface, described hydrodynamic bearing surface has the hydrodynamic pressure generation groove that a plurality of galvanochemistry process, and has the end face spine of rising between the described groove.
40. according to the Spindle Motor of claim 39, wherein said end plate is made by the steel that comprises following percentage by weight composition: C:0.6-1.20%; Si:1.0% or still less; Mn:1.0% or still less; Cr:10.5-18.0%; Mo:1.0% or still less; S:0.03% or still less; And Fe,
41. according to the Spindle Motor of claim 40, wherein said steel comprises that also percentage by weight is 0.001% or Pb still less, as unavoidable impurities.
42. according to the disk drive memory device of claim 31, wherein said steel is a stainless steel.
43. according to the disk drive memory device of claim 31, wherein produce the galvanochemistry first being processed of groove, described steel heat-treated in described hydrodynamic pressure.
44. according to the disk drive memory device of claim 43, wherein produce the galvanochemistry first being processed of groove, described steel polished in described hydrodynamic pressure.
45., see on vertical xsect wherein that described hydrodynamic bearing surface also comprises straight basically end face spine, straight inclined wall and bottom basically according to the disk drive memory device of claim 31.
46. disk drive memory device according to claim 45, wherein said straight basically end face spine is connected to described straight basically inclined wall by arc basically part, and wherein with the tangent line segment of described straight basically inclined wall by being cut with the tangent straight line of described straight basically end face spine and with the tangent straight line of the minimum point of respective grooves.
47. disk drive memory device according to claim 45, wherein each described straight basically inclined wall has a length, described length is the 75%-90% with the tangent line segment length of described straight basically inclined wall, and this line segment is by being cut with the tangent straight line of described straight basically end face spine and with the tangent straight line of the minimum point of respective grooves.
48. according to the disk drive memory device of claim 31, the surfaceness of the end face spine of wherein said rising is Ra 0.1 μ m or littler.
49. according to the disk drive memory device of claim 31, the change in depth that wherein said pressure produces groove is 0.4 μ m or littler.
50. according to the disk drive memory device of claim 31, wherein said steel comprises that also percentage by weight is 0.001% or Pb still less, as unavoidable impurities.
51. disk drive memory device according to claim 31, wherein said Spindle Motor also comprises the end plate that seals described bearing sleeve parts, described end plate has the hydrodynamic bearing surface, described hydrodynamic bearing surface has the hydrodynamic pressure generation groove that a plurality of galvanochemistry process, and has the end face spine of rising between the described groove.
52. according to the disk drive memory device of claim 51, wherein said end plate is made by the steel that comprises following percentage by weight composition: C:0.6-1.20%; Si:1.0% or still less; Mn:1.0% or still less; Cr:10.5-18.0%; Mo:1.0% or still less; S:0.03% or still less; And Fe,
53. according to the disk drive memory device of claim 52, wherein said steel comprises that also percentage by weight is 0.001% or Pb still less, as unavoidable impurities.
54. according to the disk drive memory device of claim 32, wherein said steel is a stainless steel.
55. according to the disk drive memory device of claim 32, wherein produce the galvanochemistry first being processed of groove, described steel heat-treated in described hydrodynamic pressure.
56. according to the disk drive memory device of claim 55, wherein produce the galvanochemistry first being processed of groove, described steel polished in described hydrodynamic pressure.
57., see on vertical xsect wherein that described hydrodynamic bearing surface also comprises straight basically end face spine, straight inclined wall and bottom basically according to the disk drive memory device of claim 32.
58. disk drive memory device according to claim 57, wherein said straight basically end face spine is connected to described straight basically inclined wall by arc basically part, and wherein with the tangent line segment of described straight basically inclined wall by being cut with the tangent straight line of described straight basically end face spine and with the tangent straight line of the minimum point of respective grooves.
59. disk drive memory device according to claim 57, wherein each described straight basically inclined wall has a length, described length is the 75%-90% with the tangent line segment length of described straight basically inclined wall, and this line segment is by being cut with the tangent straight line of described straight basically end face spine and with the tangent straight line of the minimum point of respective grooves.
60. according to the disk drive memory device of claim 32, the surfaceness of the end face spine of wherein said rising is Ra 0.1 μ m or littler.
61. according to the disk drive memory device of claim 32, the change in depth that wherein said pressure produces groove is 0.4 μ m or littler.
62. according to the disk drive memory device of claim 32, wherein said steel comprises that also percentage by weight is 0.001% or Pb still less, as unavoidable impurities.
63. disk drive memory device according to claim 32, wherein said Spindle Motor also comprises the end plate that seals described bearing sleeve parts, described end plate has the hydrodynamic bearing surface, described hydrodynamic bearing surface has the hydrodynamic pressure generation groove that a plurality of galvanochemistry process, and has the end face spine of rising between the described groove.
64. according to the disk drive memory device of claim 63, wherein said end plate is made by the steel that comprises following percentage by weight composition: C:0.6-1.20%; Si:1.0% or still less; Mn:1.0% or still less; Cr:10.5-18.0%; Mo:1.0% or still less; S:0.03% or still less; And Fe,
65. according to the disk drive memory device of claim 64, wherein said steel comprises that also percentage by weight is 0.001% or Pb still less, as unavoidable impurities.
66. a manufacturing has the method for the hydrodynamic bearing of spindle unit and bearing sleeve parts, described method comprises step:
Form at least one parts of described hydrodynamic bearing with steel, described steel comprises by weight percentage: C:0.6-1.20%; Si:1.0% or still less; Mn:1.0% or still less; Cr:10.5-18.0%; Mo:1.0% or still less; S:0.03% or still less; And Fe, it is 10 μ m or littler eutectic carbon granule that described steel also has diameter;
Come described at least one parts of thermal treatment by tempering and annealing;
Polish described heat treated parts; With
Galvanochemistry is processed described parts heat treated and that polished and is produced groove to form a plurality of hydrodynamic pressures, and has the end face spine of rising between the described groove.
67. according to the method for the manufacturing hydrodynamic bearing of claim 66, wherein said steel comprises that also percentage by weight is 0.001% or Pb still less, as unavoidable impurities.
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| CN102852968A (en) * | 2011-06-30 | 2013-01-02 | 日本电产株式会社 | Dynamic pressure bearing apparatus and fan |
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| US9822787B2 (en) | 2011-06-30 | 2017-11-21 | Nidec Corporation | Dynamic pressure bearing apparatus and fan |
| CN105190754A (en) * | 2012-10-12 | 2015-12-23 | 马维尔国际有限公司 | Axial field motor and method of assembling |
| CN105190754B (en) * | 2012-10-12 | 2017-06-09 | 马维尔国际有限公司 | Motor in axial magnetic field and the method for assembling hard disk drive |
| CN107882870A (en) * | 2017-11-29 | 2018-04-06 | 浙江大学 | Bionical Spiral Groove Thrust Bearing |
| CN107882870B (en) * | 2017-11-29 | 2024-03-22 | 浙江大学 | Bionic spiral groove thrust bearing |
| CN111511937A (en) * | 2017-12-26 | 2020-08-07 | 生松晃 | Spacer, hard disk drive, and method for manufacturing spacer |
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