JP2001173649A - Bearing device and technique related thereto - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate machining of a sleeve member for facilitating the whole manufacture, by attaining desired performance even if the sleeve member is manufactured by using a method in which the outer edge part of a ring-shaped surface forming a thrust bearing part of the sleeve member cannot undergo sufficient machining or treatment and eliminating the need for simultaneously satisfying the inner diameter dimension and the axial dimension relative to the thrust collar part of the sleeve part. SOLUTION: A ring-shaped spacer member 58 and a thrust member 56 are coaxially fixed in a fitting-in manner so as to be stacked on a ring-shaped surface 52c, to the inner periphery surface of a large inner diameter part 52b. On the inner periphery side of the ring-shaped spacer member 58, the thrust bearing part 80 is formed by catching the thrust collar member 22 between the ring-shaped surface 52c and the thrust member 56 of a rotating sleeve body 50. The finishing accuracy of grinding processing of the outer edge part of the ring-shaped surface 52c is not sufficient, however, the part is covered with the ring-shaped spacer member 58, therefore no adverse effect is exerted on the performance such as abrasion resistance, of the thrust bearing part 80.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sliding bearing device provided with a radial bearing portion and a thrust bearing portion, which is used for a spindle motor used for driving a recording medium, and a rotating machine provided with the bearing device. .

[0002]

2. Description of the Related Art High-capacity floppy disks, magneto-optical disks, CD-ROM /
BACKGROUND ART As a bearing device such as a spindle motor used for driving a recording medium such as an R / RW, a DVD-ROM / RAM, and a hard disk, a sliding bearing device as shown in FIG. 3 is known. This sliding bearing device has a fixed shaft body c having an annular plate-shaped thrust flange portion b near the upper end of the shaft portion a.
On the other hand, the rotary sleeve body d externally fitted to the fixed shaft body c is supported so as to be coaxially rotatable about their axis.

[0003] The rotary sleeve body d is composed of a sleeve member e and an annular thrust support plate f. The sleeve member e is located above the sleeve portion e1 and the sleeve portion e1,
A middle inner diameter portion e2 having an inner diameter larger than that of the sleeve portion e1, and a middle inner diameter portion e adjacent to the upper side of the middle inner diameter portion e2.
It has a large inner diameter portion e3 whose inner diameter is larger than that of the second inner diameter portion e3. The boundary between the inner circumferential surface of the middle inner diameter portion e2 and the inner circumferential surface of the sleeve portion e1 is formed on an annular thrust support surface e4 perpendicular to the axis, and the inner circumferential surface of the middle inner diameter portion e2 and the large inner diameter portion e3. Is formed on an annular surface e5 perpendicular to the axis. In a state where the lower surface of the thrust support plate f is in contact with the annular surface e5, the thrust support plate f is internally fitted and fixed to the large inner diameter portion e3.

[0004] The sleeve portion e1 of the sleeve member e of the rotary sleeve member d is sleeve-fitted to the shaft portion a of the fixed shaft body c, so that the outer peripheral surface of the shaft portion a and the inner peripheral surface of the sleeve member e are connected. A radial sliding bearing portion is formed in a state facing the radial direction.

The thrust flange portion b of the fixed shaft body c constitutes a thrust sliding bearing portion with its lower surface facing the thrust support surface e4 and its upper surface facing the lower surface of the thrust support plate f in the axial direction. I have.

In this conventional slide bearing device, a thrust support surface e4 which is an annular flat surface of the sleeve member e is used to form a thrust slide bearing portion. The finishing process performed on the thrust support surface e4 is preferably a polishing process or a super-finishing process in terms of accuracy,
In the case of using these processing methods, sufficient finishing accuracy cannot be obtained on the outer peripheral edge of the thrust support surface e4 due to the amplitude at the time of polishing or the roundness of the edge of a polishing instrument such as a grindstone. In order to release the thrust flange b from the outer peripheral edge having insufficient finishing precision, a radial width of at least about 0.3 mm is required. However, the inner diameter of the thrust support surface e4 on the outer peripheral side is required. It is not possible to provide a space corresponding to such a width between the portion e2 and the thrust flange portion b in terms of retaining lubricating oil in the thrust sliding bearing portion for supporting high-speed rotation.

For this reason, the thrust support surface e4 in such a thrust slide bearing portion has basically employed a cutting finish. However, since the cutting finish is not always satisfactory in terms of wear resistance, the thrust support surface e
Various measures have been taken to prevent large sliding wear from being applied to No. 4. The most effective means is to apply a magnetic preload greater than the rotor weight so that the thrust flange b does not hit the thrust support surface e4 at the time of starting and stopping. On the other hand, the power consumption at the rated rotation is increased. The result was.

In order to make the bearing clearances in the radial sliding bearing portion and the thrust sliding bearing portion appropriate, respectively, for the radial sliding bearing portion, the inner diameter of the sleeve portion e1 of the sleeve member e is set equal to that of the fixed shaft member c. It is only necessary that the distance between the thrust bearing portion e4 and the lower surface of the thrust support plate f in the axial direction is equal to the thrust flange portion of the fixed shaft body c. It suffices if it is appropriate for the axial dimension between the upper and lower surfaces in b.

However, in order to make the axial distance between the thrust support surface e4 and the lower surface of the thrust support plate f appropriate, the annular surface e5 of the sleeve member e, with which the lower surface of the thrust support plate f abuts, is connected to the thrust support surface. The axial distance between the surfaces e4 needs to be appropriate for the axial dimension between the upper and lower surfaces of the thrust flange b.

That is, for the sleeve member e, the inner diameter of the sleeve e1 and the axial distance between the annular surface e5 and the thrust support surface e4 are determined by the outer diameter of the shaft a and the upper and lower surfaces of the thrust flange b. It is necessary to simultaneously satisfy the axial dimension between them. For this reason, the precision required for processing the sleeve member e becomes severe, which has been a factor of increasing the overall manufacturing cost.

The present invention has been made in view of the above-mentioned problems in the prior art, and an object of the present invention is to provide a sliding bearing device having a radial bearing portion and a thrust bearing portion. Even if the sleeve member is manufactured using a method in which the outer peripheral edge of the annular surface constituting the thrust bearing portion cannot be sufficiently processed or processed, the expected performance can be realized. Provided is a bearing device that does not need to simultaneously satisfy the inner diameter dimension of the portion and the axial dimension with respect to the thrust flange portion, is easy to process the sleeve member, and is easy to manufacture as a whole, and a rotating machine including the bearing device. Is to do.

[0012]

According to the present invention, there is provided a bearing device, comprising: a shaft having a shaft, a thrust flange protruding radially outward from the shaft, and a sleeve. A large-diameter portion located on one end side of the sleeve portion and having an inner diameter larger than that of the sleeve portion; and a boundary portion formed between the inner peripheral surface of the sleeve portion and the inner peripheral surface of the large-diameter portion. A sleeve member having an annular surface perpendicular to the axis, wherein a sleeve portion of the sleeve member is sleeve-fitted to a shaft portion to form a radial bearing portion, and the thrust member is provided in the large inner diameter portion. A flange device in which a flange portion is located, and a shaft body and a sleeve member are relatively rotatable coaxially about their axis, wherein the thrust flange portion is arranged between the annular surface and the axial surface in the axial direction. The thrust member that constitutes the thrust bearing part An annular spacer member is fitted and fixed, and both surfaces in the axial direction abut against the outer peripheral portion of the thrust member and the outer peripheral portion of the annular surface, respectively, are internally fitted and fixed to the large inner diameter portion, and the inner periphery of the annular spacer member is fixed. The surface is radially close to the outer peripheral surface of the thrust flange, and the axial distance between the annular surface and the thrust member on the inner peripheral side of the annular spacer member is determined by the axial dimension of the annular spacer member. (Claim 1).

[0013] The annular surface constitutes a thrust bearing portion on the inner peripheral side of the annular spacer member with a thrust flange portion sandwiched between the annular surface member and the thrust member. Therefore, even if the surface roughness of the annular surface is insufficient at the portion covered by the annular spacer member such as the outer peripheral edge, if the surface roughness of the annular surface on the inner peripheral side of the annular spacer member is sufficient. As a result, the desired performance of the thrust bearing portion in terms of wear resistance and the like can be realized. That is, it can be manufactured using a method (for example, polishing or superfinishing) in which sufficient processing or processing cannot be performed on the outer peripheral edge of the annular surface, thereby achieving desired performance. .

In order to make the bearing gaps in the radial bearing portion and the thrust bearing portion appropriate, respectively, in the radial bearing portion, the inner diameter of the sleeve portion of the sleeve member is larger than the outer diameter of the shaft portion of the shaft body. As long as it is appropriate, for the thrust bearing portion, the axial direction interval between the annular surface and the thrust member on the inner peripheral side of the annular spacer member is equal to the axial direction between the axial direction surfaces of the thrust flange portion of the shaft body. It only has to be appropriate for the dimensions. To make the axial distance between the annular surface and the thrust member on the inner peripheral side of the annular spacer member appropriate, the axial dimension of the annular spacer member may be made appropriate. Therefore, as for the dimensions of the sleeve member, it is sufficient that the inner diameter of the sleeve portion is appropriate for the outer diameter of the shaft portion, and the inner diameter size of the sleeve portion and the axial size of the thrust flange portion are simultaneously satisfied. Since it is not necessary to perform the process, the processing of the sleeve member is easy, and the manufacturing is easy as a whole.

The shaft portion and the thrust flange portion of the shaft body may be formed by combining separate bodies, or may be formed integrally. As for the shape of the shaft body, for example, the shaft portion can be formed in a substantially columnar shape, and the thrust flange-shaped portion can be formed in an annular plate shape. The position of the thrust flange on the shaft can be near one end of the shaft.

[0016] In a radial bearing portion in which the sleeve portion of the sleeve member is sleeve-fitted to the shaft portion of the shaft body,
The inner peripheral surface of the sleeve portion and the outer peripheral surface of the shaft portion face each other in the radial direction via the lubricating liquid. As the lubricating liquid, for example, a lubricating oil such as a spindle oil can be appropriately selected and used.

A large-diameter portion whose inner diameter is larger than that of the sleeve portion is located at one end of the sleeve portion of the sleeve member. The inner peripheral surface of the large inner diameter portion may be, for example, a cylindrical surface shape coaxial with the sleeve portion. Also,
The boundary between the inner peripheral surface of the large inner diameter portion and the inner peripheral surface of the sleeve portion is
It is configured in an annular plane perpendicular to the axis.

A thrust member is fixedly fitted in the large inner diameter portion,
The thrust member constitutes a thrust bearing portion with the thrust flange portion interposed between the thrust member and the annular surface. Further, an annular spacer member is fitted and fixed to the large inner diameter portion, and both surfaces of the annular spacer member in the axial direction abut against the outer peripheral portion of the thrust member and the outer peripheral portion of the annular surface, respectively. The peripheral surface is opposed to the outer peripheral surface of the thrust flange portion in the radial direction. That is, on the inner peripheral side of the annular spacer member, both surfaces in the axial center direction of the thrust flange portion face the annular surface and the inner peripheral side portion of the thrust member via the lubricating liquid as described above. The inner peripheral surface of the annular spacer member and the outer peripheral surface of the thrust flange can be, for example, close enough to hold a lubricating liquid, for example, about 0.1 mm.

When the annular surface constituting the thrust bearing portion is plated, for example, in order to provide excellent wear resistance, the plated surface is roughened by plating. It is desirable to finish by polishing or the like. Further, for example, when a solid lubricant excellent in wear resistance is applied to the annular surface, it is desirable that the annular surface be finished in advance by polishing or the like with high accuracy. In such a polishing process, the outer peripheral edge of the annular surface cannot be finished with sufficient accuracy, but since the annular spacer member is located in a portion where the finishing accuracy is insufficient,
It doesn't matter.

The portion of the thrust member facing the thrust flange may be perpendicular to the axis, and the overall shape of the thrust member may be, for example, an annular plate. The annular spacer member may be, for example, an annular member having a rotationally symmetric shape about the axis, and an annular member having an inner peripheral surface coaxial with the axis. Can be.

When a thrust bearing portion is provided with a groove for generating dynamic pressure such as a herringbone groove or a spiral groove, or when a step portion is provided for a step bearing, it may be provided on a thrust flange portion and an annular surface. It can also be provided on a member.

The shaft body and the sleeve body in which the thrust member and the annular spacer member are fixed to the sleeve member can relatively rotate coaxially about their axis. In this bearing device, in addition to the shaft body being fixed and the sleeve body rotating, the sleeve body is also fixed and the shaft body rotating.

Further, another bearing device of the present invention provides a shaft body including a shaft portion, a thrust flange portion projecting radially outward from the shaft portion, a sleeve portion, and one end of the sleeve portion. Side, a large-diameter portion whose inner diameter is larger than the sleeve portion, and an annular shape perpendicular to an axis formed at the boundary between the inner peripheral surface of the sleeve portion and the inner peripheral surface of the large-diameter portion. And a sleeve member comprising a surface, a sleeve portion of the sleeve member is sleeve-fitted to a shaft portion to form a radial bearing portion, and the thrust flange portion is located within the large inner diameter portion, A bearing device in which a shaft body and a sleeve member can relatively rotate coaxially about their axis, and a thrust bearing portion sandwiching the thrust flange portion in the axial direction between the shaft surface and the sleeve surface. The thrust member is fixed inside the large-diameter portion, and the thrust member is fixed. On the outer peripheral side portion of the member, an annular spacer portion that is in contact with the outer peripheral side portion of the annular surface is provided so as to protrude in the axial direction. The distance in the axial direction between the annular surface and the thrust member on the inner peripheral side of the annular spacer portion is determined by the axial dimension of the annular spacer portion. ).

Also in this bearing device, even if the surface roughness of the annular surface is insufficient at the portion covered by the annular spacer portion such as the outer peripheral edge, the inner peripheral portion of the annular spacer portion is similar to the above device. If the surface roughness of the annular surface on the side is sufficient, desired performance of the thrust bearing portion with respect to wear resistance and the like can be realized.

In order to make the bearing gap in the thrust bearing portion appropriate in this bearing device, the axial distance between the annular surface and the thrust member on the inner peripheral side of the annular spacer portion is set to the thrust flange shape of the shaft body. What is necessary is just to be suitable for the axial dimension between both surfaces in the axial direction in the portion. In order to make the axial distance between the annular surface and the thrust member on the inner peripheral side of the annular spacer part appropriate, the axial dimension of the annular spacer part may be made appropriate. Therefore, as for the dimensions of the sleeve member, it is sufficient that the inner diameter of the sleeve portion is appropriate for the outer diameter of the shaft portion, and the inner diameter size of the sleeve portion and the axial size of the thrust flange portion are simultaneously satisfied. Since it is not necessary to perform the process, the processing of the sleeve member is easy, and the manufacturing is easy as a whole.

This bearing device differs from the bearing device in that the annular spacer is integral with the thrust member, but is otherwise the same as the bearing device.

The annular spacer portion may be, for example, an annular projection, particularly an annular projection which is rotationally symmetric about the axis, and whose inner peripheral surface is coaxial with the axis. An annular protrusion having a cylindrical surface shape can be used. For example, such an annular protrusion can be configured to project from the thrust member in the axial direction by a certain length with respect to a plane perpendicular to the axial direction and to contact the annular surface.

In each of the above bearing devices, the surface of the outer peripheral edge of the annular surface may be rougher than the surface of the portion of the annular surface facing the thrust flange.

The annular surface constitutes a thrust bearing on the inner peripheral side of the annular spacer member with the thrust flange portion interposed between the thrust member and the thrust member. Therefore, even if the surface of the outer peripheral portion of the annular surface is rougher than the surface of the portion of the annular surface facing the thrust flange portion, even if the portion covered by the annular spacer member such as the outer peripheral edge is insufficient, If the surface roughness of the annular surface (that is, the portion facing the thrust flange) on the inner peripheral side of the annular spacer member is sufficient, the desired performance of the thrust bearing portion in terms of wear resistance and the like can be realized. . That is, it can be manufactured using a method (for example, polishing or superfinishing) in which sufficient processing or processing cannot be performed on the outer peripheral edge of the annular surface, thereby achieving desired performance. .

The rotating machine according to the present invention may be provided with any one of the above bearing devices.

As an example of the rotating machine, there can be mentioned a motor such as a spindle motor employing the bearing device of the present invention as the bearing device. However, it is not necessarily limited to this. The spindle motor includes a high-capacity floppy disk, a magneto-optical disk, a CD-ROM / R / RW, a DVD-ROM / RA
M and those used for rotational drive of a recording medium such as a hard disk can be exemplified.

[0032]

Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view of a spindle motor (brushless DC motor) for driving a hard disk as an example of an embodiment of a spindle motor provided with a slide bearing device of the present invention.

The base plate 10 has a stator supporting portion 14 protruding upward in a cylindrical shape around a fitting hole 16 at a central portion.

The fixed shaft body 18 is formed by fixing an annular plate-shaped thrust flange member 22 to an upper portion of a cylindrical shaft member 20 so that the lower end of the shaft member 20 is fitted to the base plate 10. By being fitted and fixed in the mating hole 16, it is erected vertically upward. The shaft member 20 and the thrust flange member 22 are made of stainless steel.

A stator core 26 around which a stator coil 24 is wound is fixedly fitted to the stator support portion 14, and a lead portion 24a of the stator coil 24 extends through the bottom of the base plate 10 and is sealed. It is drawn downward through 10a.

The rotating sleeve body 50 is made of bronze or stainless steel, the surface of which is plated if necessary.
A sleeve member 52, an annular plate-shaped thrust member 56,
And an annular annular spacer member 58. Shaft member 2
0 and the thrust flange 22 are joined together by shrink fitting.

The sleeve member 52 has a cylindrical portion 52a having a constant inner diameter and a sleeve portion 52a.
And a large inner diameter portion 52b located adjacent to the upper end side of the main body.
The inner peripheral surface of the large inner diameter portion 52b is a cylindrical surface having a constant inner diameter with the inner diameter enlarged coaxially with the inner peripheral surface of the sleeve portion 52a. A boundary portion between the inner peripheral surface of the large inner diameter portion 52b and the inner peripheral surface of the sleeve portion 52a is formed on an annular surface 52c which is a diameter increasing surface perpendicular to the axial direction. As for the outer diameter of the sleeve member 52, similarly to the inner diameter, the outer diameter of the large inner diameter portion 52b is larger than the outer diameter of the sleeve portion 52a.

Annular spacer member 58 and thrust member 5
6 are coaxially fitted and fixed to the inner peripheral surface of the large inner diameter portion 52b while being stacked on the annular surface 52c in this order. The inner diameter of the thrust member 56 is slightly larger than the outer diameter of the shaft member 20, and the inner diameter of the annular spacer member 58 is slightly larger than the outer diameter of the thrust flange member 22. Note that the thrust member 56 and the annular spacer member 58 can be integrated.

On the inner peripheral side of the annular spacer member 58,
The annular surface 52c of the rotating sleeve body 50 and the thrust member 56
The thrust flange member 22 is sandwiched between them to form a thrust bearing portion 80. Both lower and upper surfaces of the thrust collar member 22
Each has a groove for generating a dynamic pressure, and faces the annular surface 52c and the lower surface of the thrust member 56 in the axial direction via lubricating oil.

The annular surface 52c and the lower surface of the thrust member 56 are subjected to high-precision finishing by polishing to realize good abrasion resistance. Although the finishing accuracy of the outer peripheral edge portion of the annular surface 52c is insufficient, the portion is covered with the annular spacer member 58, so that the thrust bearing portion 80 does not adversely affect performance such as wear resistance.

The outer peripheral surface of the thrust flange member 22 and the inner peripheral surface of the annular spacer member 58 are close to each other in the radial direction so as to hold the lubricating oil.

Both the inner peripheral edge of the annular surface 52c and the lower side of the inner peripheral edge of the thrust member 56 are formed into upper and lower tapered portions whose axial center gap with the thrust flange 22 gradually increases radially inward. The inner interface of the lubricating oil between the thrust collar member 22 and the annular surface 52c and the thrust member 56 is held by these tapered portions by surface tension. A circulation path 22a through which the lubricating oil circulates is provided in the thrust collar member 22 so that bubbles in the lubricating oil are released to the gas side through the inner interface of the lubricating oil in these tapered portions. Road is thrust collar member 22
And the upper and lower tapered portions on the outer peripheral side. In addition, a communication groove portion 22b is formed in the inner peripheral portion of the thrust collar member 22 to form a vertical communication hole that communicates the inner peripheral side portion of the upper and lower tapered portions with the outer peripheral surface of the shaft member 20.

A sleeve portion 52 a is sleeve-fitted to a portion of the shaft member 20 below the thrust flange member 22 and above the base plate 10 to form a radial bearing portion 90. The upper and lower portions of the outer peripheral surface of this portion of the shaft member 20 have dynamic pressure generating grooves, respectively, and are radially opposed to the inner peripheral surface of the sleeve portion 52a via lubricating oil. The outer diameter of a portion of the shaft member 20 between the two dynamic pressure generating grooves is slightly reduced. The sleeve portion 52a of the shaft member 20
The outer diameter of a portion opposed to the lower end portion is gradually reduced in a downward direction to form a tapered portion in which a radial gap with the sleeve portion 52a gradually increases, and the sleeve portion 52a and the shaft member 20 are formed.
The lower end interface of the lubricating oil is held by the tapered portion by surface tension.

The rotating sleeve body 50 is thus
It is rotatably supported by the fixed shaft 18.

In order to make the bearing clearance in the thrust bearing portion 80 appropriate, the annular surface 52c and the thrust member 56
In order to make the axial distance between the lower surface of the annular spacer member 58 and the axial dimension between the upper and lower surfaces of the thrust collar member 22 appropriate, the annular spacer member 58 sandwiched between the annular surface 52c and the thrust member 56 is formed. What is necessary is just to make the axial dimension appropriate.
Therefore, regarding the sleeve member 52, strict accuracy is not required at the same time for both the radial bearing portion 90 and the thrust bearing portion 80. Processing is easy, as long as it is appropriate for the dimensions.
The same applies to the case where the thrust member 56 and the annular spacer member 58 are integrated.

On the upper side of the thrust member 56, a large inner diameter portion 5 is provided.
An annular cap member 60 is formed coaxially with the inner peripheral surface of 2b.
Are fixed inside. An annular notch is formed in the inner lower portion of the cap member 60 to form an inwardly open groove between the upper surface of the thrust member 56 and the upper end of the thrust member 56. Is prevented.

The rotor hub 62 to which the hard disk is fitted and fixed has a substantially cylindrical shape, and has an inwardly bulging portion 62a over the entire circumference at the upper portion, and an outwardly extending portion 62b over the full circumference at the lower portion. Having. A cylindrical rotor yoke 64 is internally fixed to an inner peripheral surface of the rotor hub 62 below the inwardly protruding portion 62a, and a rotor magnet 66 is internally fixed to the inner peripheral surface. The upper inner peripheral portion of the rotor hub 62 is the large inner diameter portion 52b of the sleeve member 52.
The rotor sleeve 50 and the rotor hub 62 are coaxially integrated with each other to form a rotor, and the rotor magnet 66 forms a motor facing the stator core 26 radially outward. I have. Rotor hub 62
The lower portion of the outwardly extending portion 62b is located inside the annular concave portion 12.

FIG. 2 is a sectional view of a spindle motor (brushless DC motor) for driving a hard disk as another example of the embodiment of the spindle motor provided with the sliding bearing device of the present invention.

In this case, a cylindrical shaft member 120 is coaxially fixed to the center of a rotor hub 162 having a rotor magnet 166, and an annular plate-shaped thrust flange member 122 is attached to the lower end of the shaft member 120. Are externally fitted and fixed. These shaft member 120 and thrust collar member 122
Constitute the rotating shaft body 118.

A sleeve member 15 having a sleeve portion 152a and a large inner diameter portion 152b located adjacent to the lower end of the sleeve portion 152a in the fitting hole of the bracket 110.
2 is fixed inside. The shaft member 120 of the rotating shaft body 118 is sleeve-fitted to the sleeve 152a to form a radial bearing. The stator 125 is fixed to the bracket 110, and faces the rotor magnet 166 in the radial direction.

The inner peripheral surface of the large inner diameter portion 152b and the sleeve portion 1
A boundary portion between the inner peripheral surface 52a and the inner peripheral surface is formed on an annular surface 152c which is a radially enlarged surface perpendicular to the axial direction. The annular spacer member 158 and the disc-shaped thrust member 156 are
In this order, it is coaxially fitted and fixed to the inner peripheral surface of the large inner diameter portion 152b while being stacked on the annular surface 152c. The inner diameter of the annular spacer member 158 is slightly larger than the outer diameter of the thrust collar member 122. The thrust member 1
The 56 and the annular spacer member 158 can be integrated.

On the inner peripheral side of the annular spacer member 158, the thrust flange member 122 is sandwiched between the annular surface 152c of the sleeve member 152 and the thrust member 156 to form a thrust bearing portion.

The annular surface 152c and the thrust member 156
The upper surface is subjected to high-precision finishing by polishing to realize good abrasion resistance. Annular surface 152c
Although the finishing accuracy of the outer peripheral edge portion is insufficient, the portion is covered with the annular spacer member 158, so that the performance such as the wear resistance of the thrust bearing portion is not adversely affected.

In order to make the bearing gap in the thrust bearing portion appropriate, the annular surface 152c and the thrust member 156
In order to make the axial interval of the upper surface of the annular spacer member 158 appropriate for the axial dimension between the upper and lower surfaces of the thrust flange member 122, the annular spacer member 158 sandwiched between the annular surface 152c and the thrust member 156 is required. What is necessary is just to make the axial dimension appropriate.

[0056]

According to the bearing device and the rotary machine of the present invention, the outer peripheral edge of the annular surface constituting the thrust bearing portion in the sleeve member cannot be sufficiently processed or treated (for example, grinding or polishing). Even if it is manufactured using Zhao finishing, etc., the expected performance can be realized, and it is not necessary to simultaneously satisfy the inner diameter of the sleeve and the axial dimension with respect to the thrust flange. The processing of the sleeve member is easy and the whole is easy to manufacture.

[Brief description of the drawings]

FIG. 1 is a sectional view of a spindle motor provided with a slide bearing device.

FIG. 2 is a sectional view of another spindle motor provided with a slide bearing device.

FIG. 3 is a sectional view of a spindle motor provided with a conventional slide bearing device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Base plate 12 Annular recess 14 Stator support part 16 Fitting hole 18 Fixed shaft body 20 Shaft member 22 Thrust flange-shaped member 22a Circulation path 22b Communication groove part 24 Stator coil 24a Lead-out part 26 Stator core 50 Rotary sleeve body 52 Sleeve member 52a Sleeve part 52b Large inner diameter part 52c Annular surface 56 Thrust member 58 Annular spacer member 60 Cap member 62 Rotor hub 62a Inward bulging part 62b Outward bulging part 64 Rotor yoke 66 Rotor magnet 80 Thrust bearing part 90 Radial bearing part 110 Bracket 118 Rotating shaft 120 Shaft member 122 Thrust flange member 125 Stator 152 Sleeve member 152a Sleeve portion 152b Large inner diameter portion 152c Annular surface 156 Thrust member 158 Annular spacer member 162 Low Hub 166 rotor magnet

Claims (4)

[Claims] A shaft body having a shaft portion and a thrust flange portion projecting radially outward from the shaft portion; a sleeve portion; and a sleeve portion located at one end of the sleeve portion. A sleeve member including a large-diameter portion having an enlarged inner diameter, and an annular surface perpendicular to an axis formed at a boundary between the inner peripheral surface of the sleeve portion and the inner peripheral surface of the large-diameter portion. The sleeve portion of the sleeve member is sleeve-fitted to a shaft portion to form a radial bearing portion, the thrust flange portion is located in the large inner diameter portion, and the shaft body and the sleeve member are connected to the shaft. A bearing device capable of relatively rotating coaxially about a core wire, wherein a thrust member forming a thrust bearing portion with the thrust flange portion axially interposed between the annular surface and the annular surface is a large inner diameter portion. And both surfaces in the axial direction are An annular spacer member that abuts on an outer peripheral portion of the member and an outer peripheral portion of the annular surface is internally fitted and fixed to the large inner diameter portion. A bearing device, wherein the axial distance between the annular surface and the thrust member on the inner peripheral side of the annular spacer member is determined by the axial dimension of the annular spacer member. 2. A shaft comprising a shaft, a thrust flange extending radially outward from the shaft, a sleeve, and one end of the sleeve. A sleeve member including a large-diameter portion having an enlarged inner diameter, and an annular surface perpendicular to an axis formed at a boundary between the inner peripheral surface of the sleeve portion and the inner peripheral surface of the large-diameter portion. The sleeve portion of the sleeve member is sleeve-fitted to a shaft portion to form a radial bearing portion, the thrust flange portion is located in the large inner diameter portion, and the shaft body and the sleeve member are connected to the shaft. A bearing device capable of relatively rotating coaxially about a core wire, wherein a thrust member forming a thrust bearing portion with the thrust flange portion axially interposed between the annular surface and the annular surface is a large inner diameter portion. And the outer peripheral side portion of the thrust member An annular spacer portion which abuts on an outer peripheral side portion of the annular surface is projected in the axial direction, and an inner peripheral surface of the annular spacer portion is radially close to an outer peripheral surface of the thrust flange-shaped portion. An axial distance between the annular surface and the thrust member on the inner peripheral side of the annular spacer portion is determined by an axial dimension of the annular spacer portion. 3. The bearing device according to claim 1, wherein an outer peripheral surface of the annular surface is rougher than a surface of a portion of the annular surface facing the thrust flange. 4. A rotating machine comprising the bearing device according to claim 1, 2 or 3.