JP4226559B2 - Method for manufacturing hydrodynamic bearing device - Google Patents

Description

The present invention relates to a method for manufacturing a hydrodynamic bearing device that supports a rotating member in a non-contact manner by the hydrodynamic action of lubricating oil generated in a bearing gap. This bearing device is a spindle of information equipment such as magnetic disk devices such as HDD and FDD, optical disk devices such as CD-ROM, CD-R / RW and DVD-ROM / RAM, and magneto-optical disk devices such as MD and MO. It is suitable for a motor, a polygon scanner motor of a laser beam printer (LBP), or an electric device such as a small motor such as an axial fan.

  In addition to high rotational accuracy, the various motors are required to have high speed, low cost, low noise, and the like. One of the components that determine the required performance is a bearing that supports the spindle of the motor, and in recent years, as this type of bearing, the use of a hydrodynamic bearing having characteristics excellent in the required performance has been studied. Or it is actually used.

  For example, in a hydrodynamic bearing device incorporated in a spindle motor of a disk device such as an HDD, a radial bearing portion that supports a shaft member in a non-contact manner in a radial direction and a shaft member is supported in a non-contact manner in a thrust direction. A thrust bearing portion is provided, and a dynamic pressure bearing having a dynamic pressure generating groove (dynamic pressure groove) on the bearing surface is used as these bearing portions. The dynamic pressure groove of the radial bearing portion is formed on the inner peripheral surface of the bearing sleeve or the outer peripheral surface of the shaft member, and the dynamic pressure groove of the thrust bearing portion uses both ends of the flange portion when a shaft member having a flange portion is used. It is formed on the surface or the surface facing this (the end surface of the bearing sleeve, the end surface of the thrust member disposed on the bottom of the housing, etc.). Usually, the bearing sleeve is fixed at a predetermined position on the inner periphery of the housing, and when the bottom portion of the housing is constituted by a thrust member, an inlay portion (stepped portion) for positioning the thrust member is provided in the housing. There are many cases (the thrust member is positioned with respect to the housing by fitting the thrust member to the inlay portion). Furthermore, in order to prevent the lubricating oil injected into the internal space of the housing from leaking to the outside, a seal member is often provided at the opening of the housing.

  The hydrodynamic bearing device having the above-described configuration is composed of parts such as a housing, a bearing sleeve, a shaft member, a thrust member, and a seal member, and ensures high bearing performance required as the performance of information equipment increases. Therefore, efforts are being made to increase the processing accuracy and assembly accuracy of each part. On the other hand, with the trend toward lower prices of information equipment, the demand for cost reduction for this type of hydrodynamic bearing device has become increasingly severe.

  The subject of this invention is improving the efficiency of an assembly process and providing the dynamic pressure bearing apparatus of much lower cost.

In order to solve the above problems, the present invention provides a housing, a bearing sleeve fixed to the inner periphery of the housing, a shaft member having a shaft portion and a flange portion, a thrust member fixed to the housing, and an inner portion of the bearing sleeve. A radial bearing portion that is provided between the peripheral surface and the outer peripheral surface of the shaft portion, and that supports the shaft portion in a non-contact manner in the radial direction by the dynamic pressure action of lubricating oil generated in the radial bearing gap, and one end surface of the bearing sleeve and A first thrust bearing portion provided between one end surfaces of the opposing flange portions and supporting the flange portion in a non-contact manner in the thrust direction by a dynamic pressure action of lubricating oil generated in a thrust bearing gap; an end surface of the thrust member; and A second thrust bearing portion provided between the opposite end surfaces of the opposing flange portion and supporting the flange portion in a non-contact manner in the thrust direction by the dynamic pressure action of lubricating oil generated in the thrust bearing gap. And a method of manufacturing a dynamic pressure bearing device, and fixing the bearing sleeve on the inner circumference of the housing, a step of mounting the shaft member to the bearing sleeve, mounting the thrust member on the inner periphery of the housing, the thrust member In the state where the end surface is brought into contact with the other end surface of the flange portion, the one end surface of the flange portion is brought into contact with one end surface of the bearing sleeve, and the end surface of the thrust member is brought into contact with the other end surface of the flange portion. The axial movement of the member causes the thrust member to move axially relative to the housing and the bearing sleeve by a dimension corresponding to the total amount of the thrust bearing clearance of the first thrust bearing portion and the second thrust bearing portion together with the shaft member. are moved relative, forming a thrust bearing gap of the first thrust bearing portion and the second thrust bearing part to a predetermined size, a laser beam welding thrust member to the housing Providing a structure and a step of constant.

  As described above, in the present invention, since the thrust member is fixed to the housing by laser beam welding, the fixing operation of the thrust member can be simplified and the working time can be shortened as compared with the case where the thrust member is fixed with an adhesive or the like. Can do.

  For example, in a configuration in which the position of the thrust member is set in an inlay portion (stepped portion) provided in the housing (the thrust member is fitted to the inlay portion to position the thrust member with respect to the housing), the thrust bearing gap However, it is affected by the assembly accuracy of the bearing sleeve with respect to the housing (the axial dimension between the step portion of the spigot portion and the end surface of the bearing sleeve). In addition, since it is necessary to position the bearing sleeve with respect to the housing with a dedicated jig, when the components are finally assembled, the thrust bearing gaps become thrust surfaces (both end surfaces of the flange, bearing sleeve and thrust). It is affected by the surface accuracy of the end face of the member. On the other hand, when the position of the thrust member relative to the housing is set with reference to one end surface of the bearing sleeve positioned at a predetermined position of the housing, the thrust bearing gap is determined so that the assembly accuracy of the bearing sleeve with respect to the housing and the surface accuracy of the thrust surface are increased. Not affected. For this reason, the thrust bearing gap can be formed with high accuracy, thereby further improving the bearing performance. In addition, in order to form the thrust bearing gap with high accuracy, it is not necessary to perform parts processing or complicated assembly work with higher precision than necessary, so that the manufacturing cost of the hydrodynamic bearing device can be reduced.

  In the above configuration, the housing can be made of metal or resin (resin injection-molded product or the like). When the housing is made of metal, die-cast products such as aluminum alloys, pressed products such as metal plates (drawn products), machined products of metal materials such as brass (turned products, etc.), metal powder injection A molded article or the like can be used.

  Here, the injection molding method of the metal powder is called “metal injection molding” (MIM). This MIM method is generally a molding method in which a metal powder and a resin binder are kneaded and then injected and molded into a mold, followed by degreasing and sintering the molded body from which the binder has been removed to obtain a finished product. (After sintering, post-treatment is performed as necessary.), It has the following features. In other words, small parts with complex shapes can be formed in near net shape, mold shapes can be transferred and mass-produced with the same shape, shrinkage during molding, degreasing and sintering By determining the shrinkage rate, etc., parts with high dimensional accuracy can be produced, and the mold shape can be transferred, ensuring the same surface accuracy (surface roughness, etc.) as the mold finish accuracy. It is possible to make near-net shapes for difficult-to-process materials such as stainless steel.

  By forming the housing by the above MIM method, the manufacturing cost can be reduced. In addition to the housing, or instead of the housing, a shaft member or a thrust member may be formed by the MIM method. By using the MIM method to form a radial surface that constitutes the radial bearing portion and a member that has the thrust surface that constitutes the thrust bearing portion, such as a shaft member and a thrust member, the surface roughness of the radial surface and the thrust surface is accurate. Since it can finish well, processing cost is reduced. In addition, by processing the shape of the dynamic pressure groove in the required part of the molding die, it is possible to form (transfer) the dynamic pressure groove on the radial surface or the thrust surface at the same time as the molding. By eliminating the need for processing, processing costs can be reduced.

  Further, as means for fixing the bearing sleeve to the housing, bonding with an epoxy adhesive, press-fitting, laser beam welding (laser beam is irradiated from the outer diameter side of the housing to the fixing portion of the bearing sleeve. Or fixing the bearing sleeve. The part is directly irradiated with a laser beam.), High-frequency pulse bonding, caulking, etc. can be employed.

  In the above configuration, sealing means for sealing the internal space of the housing can be provided on the other end face side of the bearing sleeve. This sealing means can be formed by fixing the sealing member to the housing. In this case, as a means for fixing the seal member, bonding with an epoxy adhesive or the like, press-fitting, laser beam welding (irradiating a laser beam to a fixing portion of the sealing member from the outer diameter side of the housing. Direct laser beam irradiation), high frequency pulse bonding, caulking, etc. can be employed. Alternatively, the sealing means can be provided integrally with the housing. Thereby, the number of parts can be reduced and the manufacturing cost can be further reduced. The housing integrally provided with the sealing means can be formed by, for example, the above MIM method.

  In the above configuration, the bearing sleeve can be positioned with respect to the housing by the other end surface of the bearing sleeve contacting the sealing means. Thereby, the positioning operation of the bearing sleeve can be facilitated and the assembling operation can be simplified.

  In the above configuration, the inner peripheral shape of the housing is not particularly limited, but can be a straight shape in the axial direction. Thereby, the shape of the housing can be simplified and the processing cost can be reduced.

  Alternatively, a step portion may be provided on the inner periphery of the housing, and one end portion of the bearing sleeve may be in contact with the step portion so that the bearing sleeve is positioned with respect to the housing. Thereby, the positioning operation of the bearing sleeve can be facilitated and the assembling operation can be simplified.

  ADVANTAGE OF THE INVENTION According to this invention, the efficiency of an assembly process can be improved and a dynamic pressure bearing apparatus with much lower cost can be provided.

  Hereinafter, embodiments of the present invention will be described.

  FIG. 1 shows a configuration example of a spindle motor for information equipment incorporating a fluid dynamic bearing device 1 according to this embodiment. This spindle motor is used in a disk drive device such as an HDD, and includes a hydrodynamic bearing device 1 that rotatably supports a shaft member 2 in a non-contact manner, a disk hub 3 mounted on the shaft member 2, and a radial direction, for example. The motor stator 4 and the motor rotor 5 are provided to face each other through the gap. The stator 4 is attached to the outer periphery of the casing 6, and the rotor 5 is attached to the inner periphery of the disk hub 3. The housing 7 of the hydrodynamic bearing device 1 is mounted on the inner periphery of the casing 6. The disk hub 3 holds one or more disks D such as magnetic disks. When the stator 4 is energized, the rotor 5 is rotated by the exciting force between the stator 4 and the rotor 5, whereby the disk hub 3 and the shaft member 2 are rotated together.

  FIG. 2 shows the hydrodynamic bearing device 1. The hydrodynamic bearing device 1 includes a housing 7, a bearing sleeve 8 and a thrust member 10 fixed to the housing 7, and a shaft member 2.

  Between the inner peripheral surface 8a of the bearing sleeve 8 and the outer peripheral surface 2a1 of the shaft portion 2a of the shaft member 2, the first radial bearing portion R1 and the second radial bearing portion R2 are provided apart from each other in the axial direction. A first thrust bearing portion S1 is provided between the lower end surface 8c of the bearing sleeve 8 and the upper end surface 2b1 of the flange portion 2b of the shaft member 2, and the lower end surface of the end surface 10a of the thrust member 10 and the flange portion 2b. 2nd thrust bearing part S2 is provided between 2b2. For convenience of explanation, the description will be made with the thrust member 10 side as the lower side and the side opposite to the thrust member 10 as the upper side.

  The housing 7 is formed, for example, from a metal powder such as magnesium in an inverted cup shape by the MIM method, and includes a cylindrical side portion 7b and an annular seal portion 7a integrally extending from the upper end of the side portion 7b to the inner diameter side. I have. The inner peripheral surface 7a1 of the seal portion 7a faces the outer peripheral surface 2a1 of the shaft portion 2a via a predetermined seal space. Further, the inner peripheral surface 7c of the side portion 7b has a straight shape in the axial direction.

  The shaft member 2 is formed of a metal material such as stainless steel, for example, and includes a shaft portion 2a and a flange portion 2b provided integrally or separately at the lower end of the shaft portion 2a.

  The bearing sleeve 8 is formed, for example, in a cylindrical shape with a porous body made of sintered metal, particularly a sintered body made of sintered metal mainly composed of copper, and appropriately used for bonding, press-fitting, laser beam welding, high-frequency pulse bonding, and the like. By this means, the housing 7 is fixed at a predetermined position on the inner peripheral surface 7c. The upper end surface 8 b of the bearing sleeve 8 is in contact with the seal portion 7 a of the housing 7.

  On the inner peripheral surface 8a of the bearing sleeve 8 made of this sintered metal, two upper and lower regions serving as radial bearing surfaces of the first radial bearing portion R1 and the second radial bearing portion R2 are provided apart in the axial direction. In these two regions, for example, herringbone-shaped dynamic pressure grooves 8a1 and 8a2 as shown in FIG. 3A are formed. In addition, as the shape of the dynamic pressure groove, a spiral shape, an axial groove shape, or the like may be adopted.

  Further, a spiral-shaped dynamic pressure groove 8c1 as shown in FIG. 3B, for example, is formed on the lower end surface 8c of the bearing sleeve 8 serving as a thrust bearing surface of the first thrust bearing portion S1. In addition, as a shape of the dynamic pressure groove, a herringbone shape, a radiation groove shape, or the like may be adopted.

  As shown in FIG. 4, the thrust member 10 is formed in a disk shape by a MIM method from a metal powder such as magnesium, and is fixed to the lower end portion of the inner peripheral surface 7 c of the housing 7 by laser beam welding. For example, a herringbone-shaped dynamic pressure groove 10a1 as shown in FIG. 4B is formed on the end surface 10a of the thrust member 10 serving as a thrust bearing surface of the second thrust bearing portion S2. When the thrust member 10 is formed by the MIM method, the dynamic pressure groove 10a1 can be formed at the same time as molding (transferred by a molding die). In addition, you may employ | adopt spiral shape, a radiation groove shape, etc. as a shape of a dynamic pressure groove.

  The shaft portion 2 a of the shaft member 2 is inserted into the inner peripheral surface 8 a of the bearing sleeve 8, and the flange portion 2 b is accommodated in a space portion between the lower end surface 8 c of the bearing sleeve 8 and the end surface 10 a of the thrust member 10. Lubricating oil is supplied to the internal space of the housing 7 sealed by the seal portion 7a.

  When the shaft member 2 rotates, the regions (two upper and lower regions) of the inner peripheral surface 8a of the bearing sleeve 8 are opposed to the outer peripheral surface 2a1 of the shaft portion 2a via the radial bearing gap. Further, the region that becomes the thrust bearing surface of the lower end surface 8c of the bearing sleeve 8 faces the upper end surface 2b1 of the flange portion 2b via the thrust bearing gap, and the region that becomes the thrust bearing surface of the end surface 10a of the thrust member 10 is the flange. It faces the lower end surface 2b2 of the portion 2b via a thrust bearing gap. As the shaft member 2 rotates, the dynamic pressure of the lubricating oil is generated in the radial bearing gap, and the shaft portion 2a of the shaft member 2 is rotated in the radial direction by the lubricating oil film formed in the radial bearing gap. It is supported non-contact freely. Thus, the first radial bearing portion R1 and the second radial bearing portion R2 that support the shaft member 2 in a non-contact manner so as to be rotatable in the radial direction are configured. At the same time, the dynamic pressure of the lubricating oil is generated in the thrust bearing gap, and the flange portion 2b of the shaft member 2 is rotatably supported in both thrust directions by the oil film of the lubricating oil formed in the thrust bearing gap. . Thereby, the first thrust bearing portion S1 and the second thrust bearing portion S2 that support the shaft member 2 in a non-contact manner so as to be rotatable in the thrust direction are configured.

  The hydrodynamic bearing device 1 of this embodiment is assembled in a manner as shown in FIGS. 5 to 8 are upside down with respect to FIG.

  First, as shown in FIG. 5, the bearing sleeve 8 is inserted into the inner peripheral surface 7c of the housing 7 (it may be press-fitted), and its upper end surface 8b is brought into contact with the seal portion 7a. As a result, the axial position of the bearing sleeve 8 relative to the housing 7 is determined. In this state, the bearing sleeve 8 is fixed to the housing 7.

  Next, as shown in FIG. 6, the shaft member 2 is attached to the bearing sleeve 8. The inner diameter of the bearing sleeve 8 is measured in a state where the bearing sleeve 8 is fixed to the housing 7, and the radial bearing clearance is reduced by matching the outer diameter of the shaft portion 2a (measured in advance). It can be set with high accuracy.

  Next, as shown in FIG. 7, the thrust member 10 is inserted into the inner peripheral surface 7c of the housing 7 (or may be press-fitted), and is pushed forward toward the bearing sleeve 8, and the end surface 10a thereof is moved to the flange portion 2b. At the same time, the upper end surface 2 b 1 of the flange portion 2 b is brought into contact with the lower end surface 8 c of the bearing sleeve 8. This state is a state in which the thrust bearing gap is zero (the thrust bearing gap between the first thrust bearing portion S1 and the second thrust bearing portion S2 is zero). The bearing sleeve 8 may be fixed to the housing 7 at this stage.

  Next, as shown in FIG. 8, with the thrust member 10 and the shaft member 2, the thrust bearing gap (size is assumed to be δ1) of the first thrust bearing portion S1 and the thrust bearing of the second thrust bearing portion S2. The axis is moved relative to the housing 7 and the bearing sleeve 8 in the axial direction by a dimension δ (δ = δ1 + δ2) corresponding to the total amount of the gap (the size is δ2). When the thrust member 10 is fixed to the housing 7 at that position by laser beam welding, a predetermined thrust bearing gap δ (δ = δ1 + δ2) is formed.

  According to the above method, the components of the hydrodynamic bearing device 1 are actually combined to temporarily realize the state of zero thrust bearing clearance, and from this state, the thrust member 10, the housing 7, and the bearing sleeve 8 are axially connected. Since the thrust bearing gap is formed by relative movement to a predetermined amount, the assembly accuracy of the bearing sleeve 8 with respect to the housing 7 and the thrust surface (8c, 10a) can be determined only by managing the axial relative movement amount δ (δ = δ1 + δ2). 2b1, 2b2), the thrust bearing gap can be formed with high accuracy without being influenced by the surface accuracy of the flange portion 2b and the like.

  FIG. 9 shows a hydrodynamic bearing device 11 according to another embodiment. The hydrodynamic bearing device 11 is constituted by constituting a thin housing 17, a bearing sleeve 8 and a thrust member 10 fixed to the housing 17, a shaft member 2, and a seal member 9. In addition, about the components and site | parts substantially the same as the fluid dynamic bearing apparatus 1 shown in FIG. 2, the same code | symbol is attached | subjected and shown, and the overlapping description is abbreviate | omitted.

  The housing 17 is formed, for example, from a metal plate (plate material or pipe material) by press molding (drawing), and has a cylindrical side portion 17b and an annular latch integrally extending from the upper end of the side portion 17b to the inner diameter side. Part 17a. The inner diameter of the lower portion 17b1 of the side portion 17b is formed to be slightly smaller than the other portions, and the boundary portion between both is a stepped portion 17b2. In this embodiment, the stepped portion 17b2 is formed by narrowing the lower portion 17b1 of the side portion 17b to be slightly smaller in diameter than the other portions, but for example, the lower portion 17b1 of the side portion 17b and other portions The stepped portion 17b2 may be formed by making the thicknesses of the portions different from each other or by locally bending the portion corresponding to the boundary portion to the inner diameter side. Further, the stepped portion 17b2 may be formed over the entire circumference, or may be partially formed at a plurality of locations in the circumferential direction.

  The seal member 9 is fixed to the inner periphery of the upper end portion of the side portion 17 b of the housing 17, and is sandwiched between the locking portion 17 a of the housing 17 and the upper end surface 8 b of the bearing sleeve 8 in the axial direction. The inner peripheral surface 9a of the seal member 9 is opposed to the outer peripheral surface 2a1 of the shaft portion 2a via a predetermined seal space.

  The hydrodynamic bearing device 11 of this embodiment is assembled in a manner as shown in FIGS.

  First, as shown in FIG. 10, the bearing sleeve 8 is inserted into the inner periphery of the side portion 17b of the housing 17 (it may be press-fitted), and its lower end portion (on the end surface 8c side) is inserted into the side portion 17b. The seal member 9 is inserted into the inner periphery of the side portion 17b of the housing 17 (may be press-fitted), and is brought into contact with the upper end surface 8b of the bearing sleeve 8. As a result, the axial position of the bearing sleeve 8 with respect to the housing 17 is determined. In this state, the bearing sleeve 8 and the seal member 9 are fixed to the housing 17. Thereafter, the upper end portion of the side portion 17 b of the housing 17 is bent and deformed toward the inner diameter side to form the locking portion 17 a and is brought into contact with the seal member 9. Note that the side portion 17b of the housing 17 may be crimped as a means for fixing one or both of the bearing sleeve 8 and the seal member 9. In this case, a recess may be provided on the outer periphery of one or both of the bearing sleeve 8 and the seal member 9, and the side portion 17b may be caulked in the recess. Alternatively, by fixing one or both of the bearing sleeve 8 and the seal member 9 to the inner periphery of the side portion 17b, the fixing operation of these components to the housing 17 can be omitted.

  Next, as shown in FIG. 11, the shaft member 2 is mounted on the bearing sleeve 8. Then, the thrust member 10 is inserted into the inner periphery of the lower end portion 17b1 of the side portion 17b (may be press-fitted), and pushed forward toward the bearing sleeve 8, so that the end surface 10a is moved to the lower end surface of the flange portion 2b. At the same time, the upper end surface 2b1 of the flange portion 2b is brought into contact with the lower end surface 8c of the bearing sleeve 8. This state is a state in which the thrust bearing gap is zero (the thrust bearing gap between the first thrust bearing portion S1 and the second thrust bearing portion S2 is zero).

  Next, as shown in FIG. 12, with the thrust member 10 and the shaft member 2, the thrust bearing gap (the size is δ1) of the first thrust bearing portion S1 and the thrust bearing of the second thrust bearing portion S2. Relative movement in the axial direction is performed with respect to the housing 17 and the bearing sleeve 8 by a dimension δ (δ = δ1 + δ2) corresponding to the total amount of the gap (the size is δ2). When the thrust member 10 is fixed to the housing 17 at that position, a predetermined thrust bearing gap δ (δ = δ1 + δ2) is formed.

  FIG. 13 shows a hydrodynamic bearing device 21 according to another embodiment. The hydrodynamic bearing device 21 is constituted by constituting a housing 27, a bearing sleeve 8 and a thrust member 10 fixed to the housing 27, a shaft member 2, and a seal member 9. In addition, about the components and site | parts substantially the same as the fluid dynamic bearing apparatus 1 shown in FIG. 2, the same code | symbol is attached | subjected and shown, and the overlapping description is abbreviate | omitted.

  The housing 7 is formed in a cylindrical shape from a metal powder such as magnesium by the MIM method, and the inner peripheral surface 27b has a straight shape in the axial direction.

  The seal member 9 is fixed to the inner periphery of the upper end portion of the housing 27, and the inner peripheral surface 9a faces the outer peripheral surface 2a1 of the shaft portion 2a via a predetermined seal space.

  In the hydrodynamic bearing device 21 of this embodiment, the seal member 9 is first fixed to the housing 17 and then assembled in the same manner as in FIGS.

  FIG. 14 shows a hydrodynamic bearing device 31 according to another embodiment. The hydrodynamic bearing device 31 includes a housing 37, a thrust member 10 fixed to the housing 37, and the shaft member 2. Note that components and parts that are substantially the same as those of the hydrodynamic bearing device 1 shown in FIG.

  The housing 37 is made of, for example, a metal powder such as magnesium by the MIM method, and the radial bearing surface 37a of the first radial bearing portion R1, the radial bearing surface 37b of the second radial bearing portion R2, and the first thrust bearing portion S1. A thrust bearing surface 37c and a seal surface 37d are provided. For example, the radial bearing surfaces 37a and 37b and the thrust bearing surface 37c are formed with dynamic pressure grooves such as a herringbone shape and a spiral shape, and these dynamic pressure grooves are formed simultaneously with the molding of the housing 37 (transferred by a molding die). Is done.

  The hydrodynamic bearing device 31 of this embodiment is assembled in the manner described below, for example.

First, the shaft member 2 is mounted on the housing 37. Next, the thrust member 10 is inserted into the inner periphery of the lower end portion of the housing 37 (may be press-fitted), and its end surface 10a is brought into contact with the lower end surface 2b2 of the flange portion 2b, and at the same time, the upper end surface of the flange portion 2b. 2b1 is brought into contact with the thrust bearing surface 37c. This state is a state in which the thrust bearing gap is zero (the thrust bearing gap between the first thrust bearing portion S1 and the second thrust bearing portion S2 is zero). Then, with the thrust member 10 and the shaft member 2, the thrust bearing gap (size is δ1) of the first thrust bearing portion S1 and the thrust bearing gap (size is δ2) of the second thrust bearing portion S2. .)) Is moved relative to the housing 37 in the axial direction by a dimension δ (δ = δ1 + δ2) corresponding to the total amount. When the thrust member 10 is fixed to the housing 37 at that position, a predetermined thrust bearing gap δ (δ = δ1 + δ2) is formed.

It is sectional drawing of the spindle motor which has a hydrodynamic bearing apparatus which concerns on embodiment of this invention. It is sectional drawing which shows the dynamic pressure bearing apparatus which concerns on embodiment of this invention. It is sectional drawing {FIG. 3 (a)} of a bearing sleeve, and the figure {FIG. 3 (b)} which shows a lower side end surface. FIG. 4 is a cross-sectional view {FIG. 4 (a)} and a plan view {FIG. 4 (b)} of the thrust member. It is sectional drawing which shows the assembly process of the fluid dynamic bearing apparatus shown in FIG. It is sectional drawing which shows the assembly process of the fluid dynamic bearing apparatus shown in FIG. It is sectional drawing which shows the assembly process of the fluid dynamic bearing apparatus shown in FIG. It is sectional drawing which shows the assembly process of the fluid dynamic bearing apparatus shown in FIG. It is sectional drawing which shows the hydrodynamic bearing apparatus which concerns on other embodiment of this invention. It is sectional drawing which shows the assembly process of the fluid dynamic bearing apparatus shown in FIG. It is sectional drawing which shows the assembly process of the fluid dynamic bearing apparatus shown in FIG. It is sectional drawing which shows the assembly process of the fluid dynamic bearing apparatus shown in FIG. It is sectional drawing which shows the hydrodynamic bearing apparatus which concerns on other embodiment of this invention. It is sectional drawing which shows the hydrodynamic bearing apparatus which concerns on other embodiment of this invention.

Explanation of symbols

1, 11, 21, 31 Hydrodynamic bearing device 2 Shaft member 2a Shaft portion 2b Flange portion 2b1 Upper end surface 2b2 Lower end surface 7, 17, 27, 37 Housing 7a Seal portion 8 Bearing sleeve 8a Inner peripheral surface 8b Upper end surface 8c Lower Side end surface 9 Seal member 10 Thrust member 10a End surface R1 First radial bearing portion R2 Second radial bearing portion S1 First thrust bearing portion S2 Second thrust bearing portion

Claims (1)

A housing, a bearing sleeve fixed to the inner periphery of the housing, a shaft member having a shaft portion and a flange portion, a thrust member fixed to the housing, an inner peripheral surface of the bearing sleeve, and an outer periphery of the shaft portion A radial bearing portion that is provided between the bearing surface and supports the shaft portion in a non-contact manner in the radial direction by a dynamic pressure action of lubricating oil generated in a radial bearing gap, and one end surface of the bearing sleeve and the flange portion facing the radial end portion A first thrust bearing portion, which is provided between the first end surface of the thrust bearing and supports the flange portion in a thrust non-contact manner by a dynamic pressure action of lubricating oil generated in a thrust bearing gap, and is opposed to the end surface of the thrust member. A second thrust bearing provided between the other end surface of the flange portion and supporting the flange portion in a thrust direction by a dynamic pressure action of lubricating oil generated in a thrust bearing gap. Dynamic bearing device having the door, a method for manufacturing,
Fixing the bearing sleeve to the inner periphery of the housing;
Attaching the shaft member to the bearing sleeve;
Mounting the thrust member on the inner periphery of the housing, bringing the end surface of the thrust member into contact with the other end surface of the flange portion, and bringing one end surface of the flange portion into contact with one end surface of the bearing sleeve; ,
With the end face of the thrust member in contact with the other end face of the flange portion, the axial movement of the shaft member causes the thrust member to move together with the shaft member and the first thrust bearing portion and the second thrust portion. Only the dimension corresponding to the total amount of the thrust bearing gap of the bearing portion is moved relative to the housing and the bearing sleeve in the axial direction, so that the thrust bearing gap of the first thrust bearing portion and the second thrust bearing portion has a predetermined dimension. Forming the step ,
And a step of fixing the thrust member to the housing by laser beam welding.

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