JP4056349B2 - Motor equipped with a hydrodynamic bearing device - Google Patents

Motor equipped with a hydrodynamic bearing device Download PDF

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Publication number
JP4056349B2
JP4056349B2 JP2002299409A JP2002299409A JP4056349B2 JP 4056349 B2 JP4056349 B2 JP 4056349B2 JP 2002299409 A JP2002299409 A JP 2002299409A JP 2002299409 A JP2002299409 A JP 2002299409A JP 4056349 B2 JP4056349 B2 JP 4056349B2
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Japan
Prior art keywords
bearing
stator core
axial
radial
positioning
Prior art date
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Expired - Fee Related
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JP2002299409A
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Japanese (ja)
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JP2004135467A (en
Inventor
五明  正人
進悟 杉信
芦部  昇
Original Assignee
日本電産株式会社
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Priority to JP2002299409A priority Critical patent/JP4056349B2/en
Publication of JP2004135467A publication Critical patent/JP2004135467A/en
Application granted granted Critical
Publication of JP4056349B2 publication Critical patent/JP4056349B2/en
Expired - Fee Related legal-status Critical Current
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Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a motor including a dynamic pressure bearing device configured to support a fixed member and a rotating member so as to be relatively rotatable by a dynamic pressure bearing portion using dynamic pressure of a lubricating fluid.
[0002]
[Prior art]
In a general motor, a stator core made of a laminated body such as an electromagnetic steel plate is mounted on a fixed frame constituting a fixed member. A plurality of salient pole portions extend radially from the circumferential wall surface of the annular base portion of the stator core, and a drive coil is wound around each salient pole portion. An annular drive magnet attached to the rotor side is disposed so as to face and face each of the salient pole portions.
[0003]
[Problems to be solved by the invention]
However, in the laminated body such as an electromagnetic steel plate constituting the stator core of such a motor, each layer is constituted by a thin plate-like member formed by press molding, and the thin plate-like shape of each layer by an external force applied at the time of breath molding or the like. The member may be deformed into a bowl shape. And when the stator core which consists of the laminated body of the thin plate-shaped member deform | transformed in that way is mounted | worn to the fixed frame side, a stator core will not be mounted | worn at a right angle with respect to an axial direction, but will be attached in the inclined state. . When the stator core is mounted with an inclination, the rotor-side member including the drive magnet described above is always inclined at least at the time of stoppage. Alternatively, point contact is caused, and as a result, uneven wear occurs in the bearing, and the rotational performance such as the shaft runout accuracy of the motor may be easily deteriorated at an early stage.
[0004]
Such a problem related to uneven wear of the bearing becomes a very large problem in a motor using a radial dynamic pressure bearing portion that uses the dynamic pressure of a lubricating fluid, and particularly in a motor having a dynamic pressure bearing device that is made thin. Since the length is set short, it can be a fatal problem. That is, in the stator core mounted in a deformed and inclined state as described above, the axial magnetic center with the drive magnet is displaced, resulting in increased noise and the thrust direction due to dynamic pressure. As a result, there will be variations in the flying height of the bearing, which may greatly affect the dynamic pressure bearing characteristics.
[0005]
In particular, in a motor that has been reduced in size and thickness, the mechanical rigidity tends to decrease due to the reduction in the thickness of the fixed frame, and the fixed frame may be deformed by impact or vibration. Therefore, the positional relationship between the drive magnet and the stator core is likely to be shifted, and the desired bearing performance is often not obtained.
[0006]
SUMMARY OF THE INVENTION An object of the present invention is to provide a motor including a dynamic pressure bearing device that can maintain good bearing characteristics over a long period of time with a simple configuration.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, in the motor provided with the hydrodynamic bearing device according to claim 1, the fixing member is a radial positioning portion that is positioned in the radial direction by contacting the peripheral wall surface of the annular base portion of the stator core in the radial direction. And an axial positioning portion that axially contacts with the salient pole portion of the stator core, and the axial positioning portion has an annular shape that is substantially concentric with the annular base portion of the stator core. The radial positioning portion is formed so as not to contact the annular base portion of the stator core in the axial direction.
In the motor including the hydrodynamic bearing device according to claim 1 having such a configuration, even when the stator core is deformed, when the stator core is mounted on the fixed member side, the radial positioning unit and the axial positioning unit are arranged. The stator core is positioned well by the portion. In particular, the stator core is accurately held in the axial direction by the axial positioning portion, and the rigidity of the fixing member is greatly increased by the axial positioning portion integrally and continuously in the circumferential direction. The characteristics are further improved. As a result, the inclination of the shaft as in the prior art is eliminated, and the magnetic positions of the stator core side and the drive magnet side can be aligned with high accuracy. As a result, the bearing characteristics in the hydrodynamic bearing device are excellent over a long period of time. It is designed to be maintained in a proper state.
[0008]
In the motor having the hydrodynamic bearing device according to claim 2, the fixing member according to claim 1 includes a fixed frame, a substantially hollow cylindrical bearing holder provided on the fixed frame, and the bearing holder. A bearing sleeve inserted into the inner side of the fixed member, and the rotating member includes a rotating shaft rotatably inserted into the bearing sleeve of the fixed member, and the axial positioning portion is connected to the fixed frame. The bearing holder is formed by an annular peripheral wall portion that protrudes in the axial direction and contacts the salient pole portion of the stator core in the axial direction, and the radial positioning portion contacts the annular base portion of the stator core in the radial direction. It is formed by.
In such a so-called shaft rotation type motor, the above-described operation can be similarly obtained.
[0009]
Furthermore, in the motor provided with the hydrodynamic bearing device according to claim 3, the fixing member according to claim 1 is arranged concentrically with the fixed frame, the fixed shaft provided on the fixed frame, and the fixed shaft. A substantially hollow cylindrical core holder, and the rotating member includes a bearing sleeve that is rotatably inserted into the fixed shaft, and the axial positioning portion extends axially from the fixed frame. And the radial positioning portion is formed by the core holder that is in radial contact with the annular base portion of the stator core. Has been.
In such a so-called shaft-fixed motor, the above-described operation can be obtained in the same manner.
[0010]
Furthermore, in the motor provided with the hydrodynamic bearing device according to claim 4, the protruding end surface in which the axial positioning portion according to claim 2 or 3 is in contact with the salient pole portion of the stator core faces the circumferential direction. Are formed so as to form a flat surface or an uneven surface, and at least a base portion on the fixed frame side in the axial positioning portion is formed so as to be integrally continuous in the circumferential direction.
In the motor provided with the hydrodynamic bearing device according to claim 4 having such a configuration, the fixed member is formed by the portion on the protruding base side that is integrally continuous in the circumferential direction regardless of the shape of the protruding end surface of the axial positioning portion. The rigidity of the bearing is effectively enhanced, and the bearing characteristics of the hydrodynamic bearing device are further improved.
[0011]
In the motor including the hydrodynamic bearing device according to claim 5, the annular base portion of the stator core according to claim 1 is fixed to the radial positioning portion by bonding.
In the motor provided with the hydrodynamic bearing device according to claim 5 having such a configuration, since the stator core is bonded and fixed at the radial positioning portion, the rigidity of the stator core at the radial positioning portion is significantly increased. As a result, noise or the like caused by instability of the fixed state in the radial positioning portion is prevented, and the bearing characteristics of the hydrodynamic bearing device are further improved.
[0012]
Furthermore, in the motor including the hydrodynamic bearing device according to the sixth aspect, the salient pole portion of the stator core according to the fifth aspect is fixed to the projecting end surface of the axial positioning portion by bonding.
In the motor provided with the hydrodynamic bearing device according to claim 6 having such a configuration, the positioning with respect to the stator core by the axial positioning portion is particularly improved, and the rigidity of the stator core is effectively increased. The bearing characteristics of the hydrodynamic bearing device are improved.
[0013]
Furthermore, in the motor provided with the hydrodynamic bearing device according to claim 7, the peripheral wall surface of the axial positioning portion according to claim 1 is arranged so as to face the drive magnet in the radial direction. Yes.
In the motor provided with the hydrodynamic bearing device according to claim 7 having such a configuration, even if the lubricating fluid scatters from the hydrodynamic bearing device, the splattered lubricating fluid remains around the axial positioning portion. It is received by the wall surface, and further external scattering is prevented.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment in which a motor having a hydrodynamic bearing device according to the present invention is applied to a hard disk drive (HDD) will be described with reference to the drawings.
[0015]
First, as a whole, the shaft rotation / outer rotor type HDD spindle motor shown in FIG. 1 includes a stator assembly 10 as a fixed member, and a rotation side portion assembled to the stator assembly 10 from the upper side in the figure. As a rotor set 20.
[0016]
Among these, the stator set 10 has a substantially disk-shaped fixed frame 11 screwed to a plate of a magnetic disk device (not shown) as shown in FIG. A bearing sleeve 13 formed in the shape of a hollow cylinder is joined to the inner side of the cylindrical bearing holder 12 formed so as to stand upright in the center portion by a fixing means such as press fitting or shrink fitting. The bearing sleeve 13 is made of a copper-based material such as phosphor bronze in order to facilitate processing, and a center hole is formed so as to penetrate in the axial direction.
[0017]
An annular base portion 14a of the stator core 14 is inserted into the outer peripheral wall surface of the bearing holder 12, and the annular base portion 14a is fixed by injecting an adhesive into the inserted portion. Yes. A plurality of salient pole portions 14b project radially from the outer peripheral wall surface of the annular base portion 14a, and the drive coils 15 are wound around the arm ribs of the salient pole portions 14b. Further, tooth portions 14c are provided at the protruding tip portions of the salient pole portions 14b so as to project in the circumferential direction, and the teeth portions 14c are arranged in a row in the circumferential direction. Has been.
[0018]
On the other hand, in the center hole of the bearing sleeve 13, a rotating shaft 21 as a shaft member constituting a part of the rotor set 20 is rotatably inserted. The rotating shaft 21 in the present embodiment is made of stainless steel, and dynamic pressure surfaces are formed on the outer peripheral surface of the rotating shaft 21 and the inner peripheral surface of the bearing sleeve 13, respectively. The dynamic pressure surface on the rotating shaft 21 side and the dynamic pressure surface on the bearing sleeve 13 side are arranged so as to face each other through a minute gap in the radial direction, and a radial dynamic pressure bearing portion RB is configured in the minute gap portion. Has been. More specifically, in the radial dynamic pressure bearing portion RB, the dynamic pressure surface on the bearing sleeve 13 side and the dynamic pressure surface on the rotary shaft 21 side are arranged to face each other via a radial gap of several μm, and the radial gap is formed. An appropriate lubricating fluid made of lubricating oil or the like is injected into the bearing space.
[0019]
Further, on at least one side of both the dynamic pressure surfaces of the bearing sleeve 13 and the rotary shaft 21, a herringbone-shaped radial dynamic pressure generating groove (not shown), for example, is recessed in two blocks in the axial direction. When the rotary shaft 21 rotates, the lubricating fluid is pressurized by the pumping action of the radial dynamic pressure generating groove to generate dynamic pressure, and the rotary rotation fixed to the rotary shaft 21 and the rotary shaft 21 by the dynamic pressure. The hub body 22 is configured to be rotatably supported.
[0020]
The rotating hub body 22 that constitutes the rotor set 20 together with the rotating shaft 21 is formed to have a substantially cup shape for mounting a recording medium such as a magnetic disk, and is formed at the center of the rotating hub body 22. The upper end portion of the rotary shaft 21 shown in the figure is fixed to the provided joint hole 22a by a fixing means such as press fitting, shrink fitting or adhesion.
[0021]
The rotating hub body 22 has an annular standing wall portion 22b for forming a rotor portion on the outer peripheral portion, and NS is alternately magnetized on the inner peripheral surface of the annular standing wall portion 22b at regular intervals in the circumferential direction. The cylindrical drive magnet 22c is mounted and fixed to constitute a rotor portion. The drive magnet 22c is disposed close to the outer circumferential surface of the stator core 14 so as to face the ring.
[0022]
A magnetic plate 17 is disposed close to the position directly below the drive magnet 22c. The magnetic plate 17 is attached to the fixed frame 11 described above, and the entire rotor assembly 20 is attracted in the axial direction by the magnetic attraction force between the drive magnet 22c, and the rotor assembly 20 is moved in the axial direction. I try not to fall off.
[0023]
On the other hand, an annular thrust plate 23 is fixed to the tip of the rotating shaft 21 on the lower end side in the figure. The thrust plate 23 is disposed in a loosely fitted state in a housing portion 13a that is recessed in the center portion of the bearing sleeve 13 on the lower end side in the figure, and the thrust plate is placed in the housing portion 13a of the bearing sleeve 13. The dynamic pressure surface provided on the upper end face of FIG. 23 and the dynamic pressure surface on the bearing sleeve 13 side are arranged so as to be close to each other in the axial direction. A first thrust bearing portion SBa is formed in a bearing gap space between both dynamic pressure surfaces of the thrust plate 23 and the bearing sleeve 13.
[0024]
Further, a counter plate 16 made of a disk-like member is fixed so as to close the lower end side opening of the bearing sleeve 13 so as to be close to the lower dynamic pressure surface of the thrust plate 23 in the figure. A second thrust dynamic pressure bearing portion SBb is formed in a bearing gap space in which the above-described dynamic pressure surface on the lower surface side of the thrust plate 23 and the dynamic pressure surface on the upper surface side of the counter plate 16 are closely opposed to each other. ing.
[0025]
More specifically, both axial dynamic pressure surfaces on the thrust plate 23 side in the first and second thrust dynamic pressure bearing portions SBa and SBb arranged adjacent to each other in the axial direction, and the bearing sleeve 13 and Both dynamic pressure surfaces on the counter plate 16 side are arranged to face each other in the axial direction with a minute interval of several μm to several tens of μm, and the lubricating fluid enters the thrust plate 23 in the bearing space having the minute interval. It is inject | poured so that it may continue in an axial direction via the outer peripheral side channel | path.
[0026]
In the present embodiment, a known herringbone-shaped thrust dynamic pressure generating groove is annularly formed in the dynamic pressure surface corresponding to the upper and lower surfaces of the thrust plate 23, and the thrust dynamic pressure generating groove is generated during rotation. The lubricating fluid is pressurized by the pumping action of the grooves to generate dynamic pressure, and the rotating shaft 21 and the rotating hub body 22 are supported in the thrust direction by the dynamic pressure of the lubricating fluid. The thrust dynamic pressure generating groove may be formed on the dynamic pressure surface on the bearing sleeve 13 side in the first thrust bearing portion SBa and on the dynamic pressure surface on the counter plate 16 side in the second thrust bearing portion SBb.
[0027]
In the spindle motor according to the present embodiment, as described above, the inner peripheral wall surface of the annular base portion 14a of the stator core 14 is inserted into the outer peripheral wall surface of the bearing holder 12 provided on the fixed frame 11 as the fixing member. The inner peripheral wall surface of the annular base portion 14a of the stator core 14 is in contact with the outer peripheral wall surface of the bearing holder 12 in the radial direction. That is, the entire stator core 14 is configured to be positioned in the radial direction by the bearing holder 12, and thus the bearing holder 12 in the present embodiment is configured as a radial positioning portion of the stator core 14. In the present embodiment, the annular base portion 14a of the stator core 14 is fixed to the outer peripheral wall surface of the bearing holder 12 with an adhesive. At this time, the step portion 12a is arranged to be separated from the annular base portion 14a in the axial direction so that the step portion 12a provided in the bearing holder 12 does not contact the bottom surface of the stator core 14.
[0028]
On the other hand, the fixed frame 11 is integrally provided with an annular peripheral wall portion 18 protruding in the axial direction from the fixed frame 11 at a position corresponding to a position almost directly below the tooth portion 14c of each salient pole portion 14b of the stator core 14 described above. Provided. The annular peripheral wall portion 18 is formed and arranged so as to form a substantially concentric annular shape with the annular base portion 14a of the stator core 14, and the protruding front end surface in the axial direction of the annular peripheral wall portion 18 is The stator core 14 is in contact with the tooth portion 14c of each salient pole portion 14b. And in order to raise rigidity, it is good to adhere the axial direction protrusion front end surface of the annular surrounding wall part 18 and the teeth part 14c of each said salient pole part 14b with an adhesive agent.
[0029]
That is, the annular peripheral wall portion 18 is provided as an axial positioning portion of the stator core 14, and the entire stator core 14 is positioned in the axial direction by the protruding front end surface of the annular peripheral wall portion 18. . At this time, the outer peripheral wall surface of the bearing holder 12 as the radial positioning portion described above is formed so as not to contact the annular base portion 14a of the stator core 14 in the axial direction and to act on the axial positioning portion. The axial positioning portion of the stator core 14 is exclusively composed of the annular peripheral wall portion 18. It should be noted that the outer circumferential wall surface of the bearing holder 12 and the annular base portion 14a may be bonded and fixed in a state where the position in the axial direction is determined so that vibration and noise are not generated due to the fact that the annular base portion 14a is not fixed. preferable.
[0030]
In the motor provided with the hydrodynamic bearing device according to the present embodiment having the above-described configuration, even if the stator core 14 is deformed by press molding or the like as described in the related art, the stator core 14 has an annular shape. If the base portion 14a is attached to the bearing holder 12 and the teeth portion 14c of the stator core 14 is fixed by contacting the annular peripheral wall portion 18 of the fixed frame 11, the outer peripheral wall surface of the bearing holder 12 as a radial positioning portion, and The whole of the stator core 14 is positioned favorably by the protruding front end surface of the annular peripheral wall portion 18 as an axial positioning portion.
[0031]
In particular, the stator core 14 is accurately held in the axial direction by the annular peripheral wall 18 serving as the axial positioning portion, and the rigidity of the fixed frame 11 is significantly increased by the annular peripheral wall 18 integrally continuous in the circumferential direction. As a result, the bearing characteristics of the hydrodynamic bearing device are further improved. Accordingly, the conventional inclined shaft arrangement is eliminated, and the magnetic positions of the stator core 14 side and the drive magnet 22c side can be aligned with high accuracy. As a result, the bearing characteristics in the hydrodynamic bearing device are improved. It has been maintained in good condition for a long time.
[0032]
In the present embodiment, the annular base portion 14a provided on the stator core 14 is bonded and fixed to the outer peripheral wall surface of the bearing holder 12 as the radial positioning portion, and the outer peripheral wall surface of the bearing holder 12 as the radial positioning portion. Therefore, the rigidity of the stator in the axial direction by the stator core 14 and the frame 11 is greatly increased, and noise caused by instability of the fixed state is prevented. The bearing characteristics are improved further.
[0033]
Furthermore, in this embodiment, since the tooth part 14c provided in each salient pole part 14 of the stator core 14 is fixed by adhesion to an annular peripheral wall part 18 as an axial direction positioning part, the stator core 14 in particular. The alignment in the axial direction is performed very well. In addition, the rigidity of the stator core 14 is effectively increased, and the bearing characteristics of the hydrodynamic bearing device are further improved.
[0034]
Furthermore, in the present embodiment, the outer peripheral wall surface of the annular peripheral wall portion 18 as the axial positioning portion is disposed opposite to the drive magnet 22c in the radial direction. Even if the lubricating fluid is scattered from the apparatus, the scattered lubricating fluid is caused by a gap between the outer peripheral wall surface of the annular peripheral wall portion 18 as the axial positioning portion and the inner peripheral wall surface of the rotor including the rotating hub body 22. Outflow to the outside of the motor is prevented, and there is an effect that further scattering of the outside is prevented.
[0035]
On the other hand, in the embodiment described above, the protruding front end surface of the annular peripheral wall portion 18 as the axial direction positioning portion is formed so as to have a flat surface on the entire circumferential direction, but is shown in FIGS. 3 and 4. In the present embodiment, the protruding front end surface of the annular peripheral wall portion 38 as the axial positioning portion is formed so as to form an uneven surface along the circumferential direction. More specifically, a recessed portion is formed in a portion corresponding to between the adjacent tooth portions 14c, 14c in the stator core 14 on the protruding front end surface of the annular peripheral wall portion 38 in the present embodiment.
[0036]
Even in such an embodiment, basically the same operation and effect as those of the above-described embodiment can be obtained, and regardless of the shape of the projecting end surface of the annular peripheral wall portion 38, Since the protruding base side is formed so as to be integrally continuous in the circumferential direction, the rigidity of the entire stator assembly 10 including the fixed frame 11 is effectively enhanced by the annular peripheral wall 38, and as a result, The bearing characteristics of the hydrodynamic bearing device are improved. From this point, it is preferable that the recess provided in the annular peripheral wall portion 38 has a depth at least a part of which becomes a peripheral wall portion extending over the entire circumference.
[0037]
Further, the present invention utilizes the inner wall surface (the lower surface side in the drawing) of the rotating hub body 22 as in the embodiment shown in FIG. 5 in which the components corresponding to the above-described embodiment are represented by the same reference numerals. Thus, the present invention can be similarly applied to a structure in which the thrust bearing portion SB is formed.
[0038]
That is, in the embodiment shown in FIG. 5, the schematic structure of a portion different from the above-described embodiment will be described. The illustrated upper end surface of the bearing sleeve 13 and the above-described center side portion of the rotating hub body 22 are illustrated below. The end faces are arranged so as to face each other in the state of being close to each other in the axial direction, and the inside of the thrust facing area between the illustrated upper end surface of the bearing sleeve 13 and the illustrated lower end surface of the rotary hub body 22 is described above. It is formed in a bearing space continuous from the radial bearing portion RB. A thrust dynamic pressure bearing portion SB is provided in a bearing space that continues from the radial bearing portion RB. That is, a spiral or herringbone-shaped thrust dynamic pressure generating groove is formed on at least one side of the opposing dynamic pressure surfaces 13 and 22 constituting the thrust opposing region, and the thrust dynamic pressure is generated. The axially facing portion including the groove is formed in the thrust dynamic pressure bearing portion SB.
[0039]
The dynamic pressure surface on the illustrated upper end surface side of the bearing sleeve 13 constituting such a thrust dynamic pressure bearing portion SB and the dynamic pressure surface on the illustrated lower end surface side of the rotating hub body 22 adjacent to the bearing sleeve 13 are as small as several μm. An appropriate lubricating fluid is continuously filled from the above-described radial dynamic pressure bearing portion RB in the bearing space formed by the minute gap, and is disposed opposite to each other in the axial direction via the gap. The lubricating fluid is pressurized by the pumping action of the thrust dynamic pressure generating groove described above to generate dynamic pressure, and the rotary shaft 21 and the rotating hub body 22 are lifted in the thrust direction by the dynamic pressure of the lubricating fluid. The shaft is supported in a state.
[0040]
Further, a fluid seal portion including a capillary seal portion SS is defined by the outermost peripheral wall surface of the bearing sleeve 13 as the dynamic pressure bearing member. That is, the capillary seal portion SS as the fluid seal portion is provided so as to be continuously provided from the radially outer side with respect to the axial thrust facing region including the thrust dynamic pressure bearing portion SB described above, The capillary seal portion SS is defined by the outer peripheral wall surface of the bearing sleeve 13 and the inner peripheral wall surface of the counter plate 25 as a retaining member formed to face the outer peripheral wall surface of the bearing sleeve 13 in the radial direction. It is made. The counter plate 25 is composed of a ring-shaped member fixed to the flange portion 22e provided on the rotary hub body 22 described above, and is between the inner peripheral wall surface of the counter plate 25 and the outer peripheral wall surface of the bearing sleeve 13 described above. Is continuously expanded toward the opening on the lower side in the figure, thereby defining a tapered seal space. The lubricating fluid in the thrust dynamic pressure bearing portion SB is continuously filled up to the capillary seal portion SS.
[0041]
Further, at this time, the retaining sleeve 13b is provided at the upper end portion of the bearing sleeve 13 in the figure so as to project outward in the radial direction, and a part of the retaining collar 13b is described above. It arrange | positions so that a part of counterplate 25 may be opposed to an axial direction. These two members 13b and 25 are configured to prevent the rotary hub body 22 from coming off in the axial direction.
[0042]
Also in the spindle motor according to the present embodiment, the bearing holder 12 is configured as a radial positioning portion of the stator core 14, and the annular peripheral wall portion 18 is provided as an axial positioning portion of the stator core 14. Thus, the same actions and effects as those of the above-described embodiment can be obtained.
[0043]
Next, another embodiment according to the present invention will be described with reference to FIG. FIG. 6 is a cross-sectional view of a shaft rotation type inner rotor type HDD spindle motor to which the present invention is applied. As a whole, the stator assembly 40 as a fixing member and the stator assembly 40 are assembled from above in the figure. And a rotor set 50 as a rotating side portion.
[0044]
Among these, the stator set 40 has a substantially disc-shaped fixed frame 41 that is screwed to a plate of a magnetic disk device (not shown), and is formed so as to stand upright at a substantially central portion of the fixed frame 41. A bearing sleeve 43 formed in a hollow cylindrical shape is joined to the inner side of the cylindrical bearing holder 42 formed by a fixing means such as press-fitting or shrink fitting. The bearing sleeve 43 is made of a copper-based material such as phosphor bronze in order to facilitate processing, and a center hole is formed so as to penetrate in the axial direction.
[0045]
An annular base portion 45a of the stator core 45 is inserted into the inner peripheral wall surface of the core holder 44 formed at the outermost peripheral position of the fixed frame 41, and an adhesive is injected into the insertion portion. Thus, the annular base 45a is fixed. A plurality of salient pole portions 45b project radially from the inner peripheral wall surface of the annular base portion 45a, and the drive coils 46 are wound around the arm ribs of the salient pole portions 45b. Further, teeth portions 45c are provided at the projecting tip portions of the salient pole portions 45b so as to project in the circumferential direction, and the teeth portions 45c are arranged in a row in the circumferential direction. Has been.
[0046]
On the other hand, in the center hole of the bearing sleeve 43, a rotating shaft 51 as a shaft member constituting a part of the rotor set 50 described above is rotatably inserted. The rotating shaft 51 in the present embodiment is made of stainless steel, and dynamic pressure surfaces are formed on the outer peripheral surface of the rotating shaft 51 and the inner peripheral surface of the bearing sleeve 43, respectively. The dynamic pressure surface on the rotating shaft 51 side and the dynamic pressure surface on the bearing sleeve 43 side are arranged so as to face each other through a minute gap in the radial direction, and a radial dynamic pressure bearing portion RB is configured in the minute gap portion. Has been. More specifically, in the radial dynamic pressure bearing portion RB, the dynamic pressure surface on the bearing sleeve 13 side and the dynamic pressure surface on the rotary shaft 21 side are arranged to face each other via a radial gap of several μm, and the radial gap is formed. An appropriate lubricating fluid made of lubricating oil or the like is injected into the bearing space.
[0047]
Further, on at least one side of both the dynamic pressure surfaces of the bearing sleeve 43 and the rotating shaft 51, for example, a herringbone-shaped radial dynamic pressure generating groove (not shown) is provided in the axial direction so as to be divided into two blocks. When the rotating shaft 51 rotates, the lubricating fluid is pressurized by the pumping action of the radial dynamic pressure generating groove to generate dynamic pressure, and the rotational rotation fixed to the rotating shaft 21 and the rotating shaft 51 by the dynamic pressure. The hub body 52 is configured to be rotatably supported.
[0048]
The rotating hub body 52 constituting the rotor set 50 together with the rotating shaft 51 is formed so as to have a substantially cup shape with an aluminum material or the like for mounting a recording medium such as a magnetic disk. The upper end portion of the rotary shaft 51 shown in the figure is fixed to a joint hole 52a provided at the center of the shaft by a fixing means such as press fitting, shrink fitting or adhesion.
[0049]
The rotating hub body 52 has an annular standing wall portion 52b for constituting a rotor portion on the outer peripheral portion, and NS is alternately magnetized on the lower end side of the annular standing wall portion 52b in the circumferential direction at regular intervals. The cylindrical drive magnet 52c is mounted and fixed via a back yoke or the like to constitute a rotor portion. The drive magnet 52c is arranged close to the inner peripheral surface of the stator core 45 so as to face the ring. When the rotating hub body 52 is made of an iron-based metal, a back yoke is not necessary.
[0050]
On the other hand, the illustrated upper end surface of the bearing sleeve 43 and the illustrated lower end surface of the center side portion of the rotating hub body 52 are disposed so as to face each other in the state of being close to each other in the axial direction. A thrust facing region between the upper end surface and the illustrated lower end surface of the rotating hub body 52 is formed in a bearing space continuous from the above-described radial bearing portion RB. A thrust dynamic pressure bearing portion SB is provided in a bearing space that continues from the radial bearing portion RB. That is, a spiral or herringbone-shaped thrust dynamic pressure generating groove is formed on at least one side of the opposing dynamic pressure surfaces 43 and 52 constituting the thrust opposing region, and the thrust dynamic pressure is generated. The axially facing portion including the groove is formed in the thrust dynamic pressure bearing portion SB.
[0051]
The dynamic pressure surface on the upper end surface side of the bearing sleeve 43 that constitutes such a thrust dynamic pressure bearing portion SB and the dynamic pressure surface on the lower end surface side of the rotating hub body 52 that is close to and opposed to the bearing sleeve 43 are as small as several μm. An appropriate lubricating fluid is continuously filled from the above-described radial dynamic pressure bearing portion RB in the bearing space formed by the minute gap, and is opposed to each other in the axial direction via the gap. The lubricating fluid is pressurized by the pumping action of the thrust dynamic pressure generating groove described above to generate dynamic pressure, and the rotary shaft 51 and the rotary hub body 52 are lifted in the thrust direction by the dynamic pressure of the lubricating fluid. The shaft is supported in a state.
[0052]
Further, a fluid seal portion including a capillary seal portion SS is defined by the outermost peripheral wall surface of the bearing sleeve 43 as the dynamic pressure bearing member. That is, the capillary seal portion SS as the fluid seal portion is provided so as to be continuously provided from the radially outer side with respect to the axial thrust facing region including the thrust dynamic pressure bearing portion SB described above, The capillary seal portion SS is defined by the outer peripheral wall surface of the bearing sleeve 43 and the inner peripheral wall surface of the counter plate 55 as a retaining member formed to face the outer peripheral wall surface of the bearing sleeve 43 in the radial direction. It is made. The counter plate 55 is made of a ring-shaped member fixed to the flange portion 52e provided on the rotating hub body 52, and is between the inner peripheral wall surface of the counter plate 55 and the outer peripheral wall surface of the bearing sleeve 43 described above. Is continuously expanded toward the opening on the lower side in the figure, thereby defining a tapered seal space. The lubricating fluid in the thrust dynamic pressure bearing portion SB is continuously filled up to the capillary seal portion SS.
[0053]
Further, at this time, the retaining sleeve 43b is provided on the upper end portion of the bearing sleeve 43 in the drawing so as to project outward in the radial direction, and a part of the retaining collar 43b is described above. The counter plate 55 is disposed so as to face a part of the counter plate 55 in the axial direction. These two members 43b and 55 are configured to prevent the rotating hub body 52 from coming off in the axial direction.
[0054]
Furthermore, in the spindle motor in the present embodiment, the outer peripheral wall surface of the annular base portion 45a of the stator core 45 is inserted into the inner peripheral wall surface of the core holder 44 provided on the fixed frame 41 as the fixing member as described above. Accordingly, the entire stator core 45 is positioned in the radial direction. That is, the inner peripheral wall surface of the core holder 44 is formed as a radial positioning portion of the stator core 45.
[0055]
On the other hand, the fixed frame 41 is integrally formed with an annular peripheral wall portion 48 that protrudes in the axial direction at a position corresponding to a position almost directly below the tooth portion 45c of each salient pole portion 45b of the stator core 45 described above. Yes. The annular peripheral wall portion 48 is formed and arranged so as to form a substantially concentric annular shape with the annular base portion 45a of the stator core 45, and the axially protruding front end surface of the annular peripheral wall portion 48 is Abutting against the tooth portion 45c of each salient pole portion 45b of the stator core 45, the axially projecting tip surface of the annular peripheral wall portion 48 and the tooth portion 45c are fixed by an adhesive.
[0056]
That is, the annular peripheral wall portion 48 is provided as an axial positioning portion of the stator core 45, and the entire stator core 45 is positioned in the axial direction by the protruding front end surface of the annular peripheral wall portion 48. At this time, the inner peripheral wall surface of the core holder 44 as the radial positioning portion described above is formed so as not to contact the annular base portion 45a of the stator core 45 in the axial direction. Is configured by a protruding front end surface of the annular peripheral wall portion 48.
[0057]
In the motor including the hydrodynamic bearing device according to the present embodiment having the above-described configuration, as described in the related art, even if the stator core 45 is deformed by press molding or the like, the circle of the stator core 45 When the annular base portion 45a is attached to the core holder 44 and the teeth portion 45c of the stator core 45 is brought into contact with and fixed to the annular peripheral wall portion 48 of the fixed frame 41, the inner periphery of the core holder 44 as a radial positioning portion is secured. The entire stator core 45 is well positioned by the wall surface and the protruding front end surface of the annular peripheral wall portion 48 as an axial positioning portion.
[0058]
In particular, the stator core 45 is accurately held in the axial direction by the annular peripheral wall 48 serving as an axial positioning portion, and the rigidity of the fixed frame 41 is significantly increased by the annular peripheral wall 48 that is integrally continuous in the circumferential direction. As a result, the bearing characteristics of the hydrodynamic bearing device are further improved. Accordingly, the conventional inclined shaft arrangement is eliminated, and the magnetic positions of the stator core 45 side and the drive magnet 52c side can be aligned with high accuracy. As a result, the bearing characteristics in the hydrodynamic bearing device are improved. It has been maintained in good condition for a long time.
[0059]
As mentioned above, the invention made by the present inventor has been specifically described based on the embodiments. However, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the invention. Needless to say.
[0060]
For example, each of the embodiments described above applies the present invention to a shaft rotation type motor, but the present invention can be similarly applied to a shaft fixed type motor.
[0061]
In each of the above embodiments, the present invention is applied to a hard disk drive. However, the present invention is not limited to this, and the disk device used in various other devices, other The same can be applied to various motors.
[0062]
Furthermore, the present invention can be similarly applied not only to a motor having a hydrodynamic bearing device but also to a motor having an oil-impregnated bearing device.
[0063]
【The invention's effect】
As described above, the motor including the hydrodynamic bearing device according to claim 1 of the present invention includes the radial positioning portion that radially contacts the annular base portion of the stator core and positions the stator core in the radial direction, and the stator core. Even if the stator core is deformed, it is continuously continuous in the circumferential direction by providing the fixing member with an annular axial positioning portion that axially contacts the salient pole portion of the stator and positions the stator core in the axial direction. The annular axial positioning portion holds the stator core in the axial direction with high accuracy and greatly increases the rigidity of the fixed member, thereby improving the bearing characteristics of the hydrodynamic bearing device and eliminating the shaft inclination. Since the magnetic position of the motor and the drive magnet side can be aligned with high accuracy, the bearing in the hydrodynamic bearing device can be configured with a simple configuration. Can maintain sex in good condition for a long time, thereby improving the reliability of the motor having a dynamic pressure bearing device.
[0064]
Further, the present invention is a so-called shaft rotation type motor such as a motor provided with the hydrodynamic bearing device according to claim 2, such as a motor provided with the hydrodynamic bearing device according to claim 3, The effects described above can be obtained in the same manner in a so-called shaft-fixed motor.
[0065]
Further, in the present invention, the motor including the hydrodynamic bearing device according to claim 4 is configured such that the rigidity of the fixing member is effectively increased by the projecting base side portion integrally continuous in the circumferential direction. The same effect can be obtained regardless of the shape of the protruding end face of the axial positioning portion.
[0066]
According to a fifth aspect of the present invention, there is provided a motor including the hydrodynamic bearing device, wherein the annular base portion provided on the stator core according to the first aspect is fixed to the radial positioning portion by bonding, thereby the rigidity of the stator core. Since the bearing characteristics of the hydrodynamic bearing device are further improved, the above-described effects can be further enhanced.
[0067]
Furthermore, a motor including the hydrodynamic bearing device according to claim 6 fixes the salient pole portion provided on the stator core in claim 5 to the axial positioning portion by adhesion, and in particular, the stator core by the axial positioning portion. Further, the above-described effects can be further enhanced since the rigidity of the stator core is effectively increased to improve the bearing characteristics of the hydrodynamic bearing device.
[0068]
Furthermore, a motor provided with the hydrodynamic bearing device according to claim 7 is configured such that the peripheral wall surface of the axial positioning portion in claim 1 is disposed in close proximity to the drive magnet in the radial direction. In addition to the above-described effects, even if the lubricating fluid scatters from the hydrodynamic bearing device, the scattered lubricating fluid is received by the peripheral wall surface of the axial positioning portion to prevent further external scattering. Thus, the cleanliness of the motor can be improved.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a hard disk drive device incorporating a spindle motor having a hydrodynamic bearing device according to an embodiment of the present invention.
2 is an explanatory plan view showing a structure of a stator portion of the motor shown in FIG. 1; FIG.
FIG. 3 is an explanatory plan view showing the structure of a stator portion of a motor according to another embodiment of the present invention.
FIG. 4 is an explanatory side view of the stator portion shown in FIG. 4;
FIG. 5 is a longitudinal sectional view of a hard disk drive device incorporating a spindle motor having a hydrodynamic bearing device according to still another embodiment of the present invention.
FIG. 6 is a longitudinal sectional explanatory view of a hard disk drive device incorporating an inner rotor type spindle motor having a hydrodynamic bearing device according to still another embodiment of the present invention.
[Explanation of symbols]
11 Fixed frame
12 Bearing holder (radial positioning part)
13 Bearing sleeve
14 Stator core
14a annular base
14b Salient pole
14c Teeth club
15 Drive coil
18 Annular peripheral wall (axial positioning part)
RB radial dynamic pressure bearing
SB Thrust bearing
21 Rotating shaft
22 Rotating hub body
22c Drive magnet
38 Annular peripheral wall (axial positioning part)
41 Fixed frame
42 Bearing holder (radial positioning part)
43 Bearing sleeve
45 Stator core
45a Toroidal base
45b Salient pole
45c Teeth Club
46 Drive coil
48 Annular peripheral wall (axial positioning part)
RB radial dynamic pressure bearing
SB Thrust bearing
51 Rotating shaft
52 Rotating hub body
52c Drive magnet

Claims (7)

  1. The fixed member and the rotating member are supported so as to be relatively rotatable by a radial dynamic pressure bearing portion using the dynamic pressure of the lubricating fluid,
    The fixing member is mounted with a stator core having a plurality of salient pole portions extending radially from the peripheral wall surface of the annular base portion in the radial direction,
    In the motor provided with the hydrodynamic bearing device in which the rotating member is provided with an annular drive magnet facing the salient pole portion in the radial direction,
    The fixing member is positioned in the axial direction by abutting in the axial direction on the salient pole portion of the stator core, and a radial positioning portion that is in radial contact with the peripheral wall surface of the annular base portion of the stator core. An axial positioning portion,
    The axial positioning portion is formed so as to form a substantially concentric annular shape with the annular base portion of the stator core,
    The motor provided with a hydrodynamic bearing device, wherein the radial positioning portion is formed so as not to contact the annular base portion of the stator core in the axial direction.
  2. The fixing member includes a fixing frame, a substantially hollow cylindrical bearing holder provided in the fixing frame, and a bearing sleeve inserted through the inner side of the bearing holder,
    The rotating member includes a rotating shaft that is rotatably inserted into a bearing sleeve of the fixed member,
    The axial positioning portion is formed by an annular peripheral wall portion that protrudes in the axial direction from the fixed frame and contacts the salient pole portion of the stator core in the axial direction.
    The motor with a hydrodynamic bearing device according to claim 1, wherein the radial positioning portion is formed by the bearing holder that is in radial contact with an annular base portion of the stator core.
  3. The fixing member includes a fixed frame, a fixed shaft provided on the fixed frame, and a substantially hollow cylindrical core holder disposed concentrically with the fixed shaft,
    The rotating member includes a bearing sleeve inserted rotatably with respect to the fixed shaft,
    The axial positioning portion is formed by an annular peripheral wall portion that protrudes in the axial direction from the fixed frame and contacts the salient pole portion of the stator core in the axial direction.
    2. The motor having a hydrodynamic bearing device according to claim 1, wherein the radial positioning portion is formed by the core holder that is in radial contact with an annular base portion of the stator core.
  4. The protruding end surface where the axial positioning portion abuts on the salient pole portion of the stator core is formed so as to form a flat surface or an uneven surface shape in the circumferential direction,
    4. A motor having a hydrodynamic bearing device according to claim 2, wherein at least a base portion on the fixed frame side in the axial direction positioning portion is formed so as to be integrally continuous in the circumferential direction.
  5. The motor including the hydrodynamic bearing device according to claim 1, wherein an annular base portion of the stator core is fixed to the radial positioning portion by bonding.
  6. 6. The motor having a hydrodynamic bearing device according to claim 5, wherein the salient pole part of the stator core is fixed to the projecting end face of the axial positioning part by adhesion.
  7. The motor provided with the hydrodynamic bearing device according to claim 1, wherein a peripheral wall surface of the axial positioning portion is disposed so as to oppose the drive magnet in the radial direction.
JP2002299409A 2002-10-11 2002-10-11 Motor equipped with a hydrodynamic bearing device Expired - Fee Related JP4056349B2 (en)

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Publication number Priority date Publication date Assignee Title
WO2009116525A1 (en) * 2008-03-18 2009-09-24 日本電産株式会社 Motor
JP5210054B2 (en) * 2008-06-04 2013-06-12 サムスン電機ジャパンアドバンスドテクノロジー株式会社 Motor and disk drive using the same
JP2012055075A (en) 2010-08-31 2012-03-15 Nippon Densan Corp Spindle motor and disk drive device
JP2014103727A (en) 2012-11-19 2014-06-05 Nippon Densan Corp Spindle motor and disk drive device
JP2014103726A (en) 2012-11-19 2014-06-05 Nippon Densan Corp Spindle motor and disk drive device
KR101412863B1 (en) * 2013-02-13 2014-06-26 삼성전기주식회사 Spindle motor and driving device of recording disk having the same

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