JP2000240642A - Bearing device and its related technique - Google Patents

Abstract

PROBLEM TO BE SOLVED: To hardly cause seizure both in a radial bearing part and in a thrust bearing part, to effectively prevent damage, abrasion and lowering of rotational accuracy due to the abrasion in the thrust bearing, to eliminate the need of satisfying the inside diameter of a sleeve part and the dimensions in the axial direction to the thrust collar part at the same time, to easily machine the sleeve member and facilitate manufacture as a whole. SOLUTION: The sleeve part 52a of a sleeve member 52 made of bronze in a roary sleeve body 50 is sleeve-fitted to a shaft member 20 in a fixed shaft body 18 made of stainless steel. A lower thrust member 54, a spacer member 58 and an upper thrust member 56 are stacked in order on an annular enlarged diameter surface 52c and coaxially internally fixed to the inner peripheral surface of the large inside diameter part 52b of the sleeve member 52. The upper and lower surfaces of a thrust collar member 22 are opposite to a lower thrust member 54 and an upper thrust member 56 constituting the rotary sleeve member 50. The lower thrust member 54 and the upper thrust member 56 are made of stainless steel harder than that of the fixed shaft body 18.

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 used for a spindle motor or the like 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-ROMs,
As a bearing device such as a spindle motor used for driving a recording medium such as a DVD and a hard disk, a sliding bearing device as shown in FIG. 3 is known. In this sliding bearing device, a rotating sleeve body d externally fitted to the fixed shaft body c is provided on a fixed shaft body c having an annular plate-shaped thrust flange b near the upper end of the shaft part a. Are supported so that they can rotate coaxially 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 sliding bearing device, in order to prevent seizure from easily occurring between the fixed shaft member c and the rotating sleeve member d during use, each member of the rotating sleeve member d is made of a bronze material or the like. And each member of the fixed shaft c is formed of a relatively hard material such as stainless steel. Therefore, in the thrust sliding bearing portion having a high peripheral speed, the thrust support surface e4 of the sleeve member e made of bronze material or the lower surface of the thrust support plate f is damaged by the thrust flange portion b made of stainless steel, When the perpendicularity of the thrust flange b to the body c is bad, the thrust flange b may be damaged by the outer peripheral edge, and may be damaged by the edge of the dynamic pressure groove provided in the thrust flange b. In addition, the thrust support surface e4 of the sleeve member e or the lower surface of the thrust support plate f is likely to be worn. Further, since the thrust support surface e4 of the sleeve member e made of bronze material is difficult to obtain the roughness accuracy due to the construction method, the thrust support surface e4 has minute irregularities and is easily worn by the thrust flange portion b.

Further, in order to make the bearing gaps in the radial sliding bearing portion and the thrust sliding bearing portion appropriate, respectively, for the radial sliding bearing portion, the dimension of the inner diameter of the sleeve portion e1 of the sleeve member e is equal to that of the fixed shaft body 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, which is in contact with the lower surface of the thrust support plate f, and the thrust support surface f5. 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, as 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. And a rotating machine equipped with the bearing device, in which seizure hardly occurs in both the radial bearing portion and the thrust bearing portion, and damage or wear of the thrust bearing portion and a decrease in rotation accuracy due to the bearing device are effectively prevented. Also, the present invention is provided with a bearing device and a bearing device which can easily process the sleeve member and can be easily manufactured as a whole without having to simultaneously satisfy the inner diameter size of the sleeve portion and the axial size with respect to the thrust flange portion. It is to provide a rotating machine.

[0011]

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. And a sleeve member which is located at one end side of the sleeve portion and has a large inner diameter portion whose inner diameter is larger than the sleeve portion, wherein the sleeve portion is sleeve-fitted to the shaft portion. A radial bearing portion, wherein the thrust flange portion is located in the large inner diameter portion, a bearing device in which the shaft body and the sleeve member can relatively rotate coaxially about their axis. A first thrust member and a second thrust member each having a first thrust support portion and a second thrust support portion facing each other in the axial direction are disposed in the large inner diameter portion, and they are fixed to a sleeve member. 1 thrust support and The thrust flange portion is sandwiched between thrust support portions to form a thrust bearing portion, and the outer peripheral surface of the shaft portion and the axial center surface of the thrust flange portion are smaller than the inner peripheral surface of the sleeve portion. Are characterized in that the first thrust support portion and the second thrust support portion are harder than both surfaces of the thrust flange portion in the axial direction (claim 1).

The outer peripheral surface of the shaft portion is harder than the inner peripheral surface of the sleeve portion, and the first thrust support portion and the second thrust support portion are harder than the axial center surfaces of the thrust flange portion. Therefore, also between the sleeve and the shaft, the first
Seizure hardly occurs between the thrust support and the second thrust support and the thrust flange. Also, since the first thrust support portion and the second thrust support portion are harder than the axial center surfaces of the thrust flange portion, the first thrust support portion or the second thrust support portion is formed of the thrust flange portion. Damage due to the outer peripheral edge and reduction in rotational accuracy due to wear between the first and second thrust members and the thrust flange are effectively prevented.

[0013] The shaft portion and the thrust flange portion of the shaft body may be formed by combining separate members, 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.

[0014] 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 a lubricant. As the lubricant, for example, a lubricating oil such as a spindle oil can be appropriately selected and used.

The first thrust member and the first thrust support portion of the first and second thrust members are disposed at one end side of the sleeve portion of the sleeve member and are disposed in the large inner diameter portion having an inner diameter larger than that of the sleeve portion. A thrust flange portion is sandwiched between the second thrust support portions to form a thrust bearing portion. That is, both surfaces in the axial center direction of the thrust flange portion face the first thrust support portion and the second thrust support portion via the lubricant as described above. In this thrust bearing portion, for example, the first thrust support portion and the second thrust support portion each form an annular surface, and the first thrust support portion, the second thrust support portion, and the axial center surfaces of the thrust flange portion. Of these, portions forming a thrust bearing portion relative to the first thrust support portion and the second thrust support portion may be respectively perpendicular to the axial direction.

The inner peripheral surface of the large-diameter portion may have, for example, a cylindrical 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 can be formed, for example, in an annular surface shape perpendicular to the axial direction.

The shapes of the first and second thrust members can be, for example, annular plates.

The shaft body, and the sleeve body in which the first thrust member and the second thrust member are fixed to the sleeve member,
They can rotate relative to each other coaxially about their axes.
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.

The outer peripheral surface of the shaft portion and the axially opposite surfaces of the thrust flange portion may have the same hardness or different hardnesses. The axially opposite surfaces of the thrust flange portion refer to the upper and lower surfaces of the thrust flange portion if the axial direction is the vertical direction. Both surfaces in the axial direction of the thrust flange portion, the first thrust support portion and the second thrust support portion have the same hardness in normal cases. For example, the inner peripheral surface of the sleeve part is made of bronze material,
The outer peripheral surface of the shaft portion and the axially opposite surfaces of the thrust flange portion may be made of stainless steel, and the first thrust support portion and the second thrust support portion may be made of stainless steel harder than the stainless steel. it can.

In the bearing device of the present invention, each of the sleeve member, the shaft portion, the thrust flange portion, the first thrust member and the second thrust member has not only a fixed surface but also a fixed hardness as a whole. Thus, the shaft portion and the thrust flange portion are harder, and the first thrust member and the second thrust member can be harder than the thrust flange portion. In this case, since the shaft portion and the thrust flange portion are relatively hard, the shaft portion and the thrust flange portion are separate bodies, and the thrust flange portion is fitted and fixed to the shaft portion by tight fitting. When the shaft portion and the thrust flange-shaped portion are removed, the withdrawal strength (fitting strength) is relatively high.

According to the bearing device of the present invention, one of the first thrust member and the second thrust member projects radially outward from the thrust flange-shaped portion toward the other thrust member and abuts on the thrust member. The distance between the first thrust support portion and the second thrust support portion in the axial direction can be determined by the axial dimension of the spacer portion (claim 2).

In order to make the bearing gaps in the radial bearing portion and the thrust bearing portion appropriate, 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 in the radial bearing portion. As long as it is appropriate, for the thrust bearing portion, the axial distance between the first thrust support portion and the second thrust support portion is larger than the axial dimension between both axial directions of the thrust flange portion of the shaft body. It is good if appropriate. In order to make the axial distance between the first thrust support portion and the second thrust support portion appropriate, a spacer included in one of the first thrust member and the second thrust member provided in the large inner diameter portion of the sleeve member is provided. What is necessary is just to make the axial dimension of a part suitable. 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. You don't have to. Therefore, the processing of the sleeve member is easy, and the manufacture is easy as a whole.

The spacer portion is, for example, an annular protrusion, in particular,
An annular protrusion having a rotationally symmetric shape with respect to the axis may be formed, and an annular protrusion having an inner peripheral surface coaxial with the axis may be formed. For example, such an annular protrusion can be configured to protrude from the one thrust member by a certain length in the axial direction with reference to a plane perpendicular to the axial direction, and to contact the other thrust member.

In the bearing device of the present invention, a spacer member separate from the first thrust member and the second thrust member radially outward of the thrust flange is provided.
Both surfaces in the axial direction of the spacer member are in contact with the first thrust member and the second thrust member, respectively, and the axes of the first thrust support portion and the second thrust support portion depend on the axial size of the spacer member. The spacing in the center direction may be determined (claim 3).

Also in this case, similarly to the above, in order to make the axial distance between the first thrust support portion and the second thrust support portion appropriate, the first thrust support portion located within the large inner diameter portion of the sleeve member.
What is necessary is just to make the axial dimension of the spacer member provided between the thrust member and the second thrust member 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 spacer member in this case is separate from the first thrust member and the second thrust member. For example, the spacer member may be an annular member, particularly, an annular member having a rotationally symmetric shape about the axis. And an annular member having a cylindrical surface whose inner peripheral surface is coaxial with the axis. Such an annular member may be, for example, internally fitted and fixed to the large-diameter portion in a state where both surfaces in the axial direction abut against the first thrust member and the second thrust member, respectively.
It is desirable that the linear expansion coefficient of the spacer member be larger than the linear expansion coefficient of the thrust flange in consideration of temperature compensation.

A rotary machine according to the present invention may include the bearing device according to the present invention.

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. Examples of the spindle motor include those used for rotating a recording medium such as a high-capacity floppy disk, a magneto-optical disk, a CD-ROM, a DVD, and a hard disk.

[0029]

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 an annular concave portion 12 having an upper opening, a stator supporting portion 14 protruding upward in a cylindrical shape on the inner peripheral side of the annular concave portion 12, and 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 the same 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 rotary sleeve body 50 includes a sleeve member 52 made of bronze material, the shaft member 20 and the thrust flange member 2.
2 is composed of an annular plate-shaped lower thrust member 54 and an upper thrust member 56 made of stainless steel which is harder than the stainless steel constituting component 2 and an annular spacer member 58. Shaft member 2
0 and the thrust flange member 22 are joined by shrink fitting, and are made of stainless steel harder than the bronze material, so that the pull-out strength is relatively high.

The sleeve member 52 has a cylindrical portion 52a having a constant inner diameter and a cylindrical 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. The boundary 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 enlarged diameter surface 52c 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.

The lower thrust member 54, the spacer member 58, and the upper thrust member 56 are coaxially fitted and fixed to the inner peripheral surface of the large inner diameter portion 52b while being stacked on the annular enlarged diameter surface 52c in this order. . The inner diameters of the lower thrust member 54 and the upper thrust member 56 are slightly larger than the outer diameter of the shaft member 20, and the inner diameter of the spacer member 58 is
2 is slightly larger than the outside diameter.

The lower thrust member 54 of the rotary sleeve body 50
The thrust flange member 22 is sandwiched between the upper thrust member 56 and the upper thrust member 56 to form a thrust bearing portion 80. The lower and upper surfaces of the thrust collar member 22 each have a groove for generating dynamic pressure,
The upper surface of the lower thrust member 54 (first thrust support portion) and the lower surface of the upper thrust member 56 (second thrust support portion) are opposed in the axial direction via the lubricating oil. Lower thrust member 54
The upper inner peripheral edge of the upper thrust member 56 and the lower inner peripheral edge of the upper thrust member 56 are both formed into upper and lower tapered portions whose axial center gap with the thrust flange member 22 gradually increases radially inward. The inner interface of the lubricating oil between the shape member 22 and the lower thrust member 54 and the upper thrust member 56 is configured to be held by these tapered portions by surface tension. Further, 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 opened to the gas side through the inner interface of the lubricating oil in these tapered portions. The circulation path opens on the outer peripheral surface of the thrust flange member 22 and on the outer peripheral side of the upper and lower tapered portions. 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 gap in the thrust bearing portion 80 appropriate, the axial distance between the upper surface of the lower thrust member 54 and the lower surface of the upper thrust member 56 is set in the axial direction between the upper and lower surfaces of the thrust flange member 22. To make the dimension appropriate, the axial dimension of the spacer member 58 sandwiched between the lower thrust member 54 and the upper thrust member 56 may be made 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, and the inner diameter of the sleeve portion 52 a with respect to the radial bearing portion 90 is smaller than the outer diameter of the shaft member 20. As long as it is appropriate for the dimensions,
Processing is easy.

On the upper side of the upper thrust member 56, an annular cap member 6 is coaxial with the inner peripheral surface of the large inner diameter portion 52b.
0 is fixed inside. An annular notch is formed in the inner lower portion of the cap member 60 to form a groove-like portion having an inward opening between the cap member 60 and the upper surface of the upper thrust member 56. The groove-like portion scatters the lubricant oil droplets upward. Is prevented.

The rotor hub 62 to which the hard disk is externally fixed has a substantially cylindrical shape, and has an inwardly bulging portion 62a over the entire periphery at the upper portion thereof, and an outwardly swelling portion 62b over the entire periphery at the lower portion thereof. 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.

In this spindle motor, in the radial bearing portion 90, the sleeve member 5 made of bronze material is used.
2, the outer peripheral surface of the stainless steel shaft member 20 is harder than the inner peripheral surface of the stainless steel shaft member 20. Since the upper and lower surfaces of the lower thrust member 54 and the upper thrust member 56 made of hard stainless steel are harder, seizure hardly occurs in both the radial bearing portion 90 and the thrust bearing portion 80. Also, since the upper and lower thrust members 54 and 56 are harder than the upper and lower surfaces of the thrust flange member 22, the upper and lower thrust members 54 and 56 may be damaged by the outer peripheral edge of the thrust flange member 22. A decrease in rotation accuracy due to wear between the members 54 and 56 and the thrust flange member 22 is effectively prevented.

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

This spindle motor has an annular spacer portion 154a projecting upward on the outer peripheral side of the lower thrust member 154, and has no spacer member. The inner diameter of the spacer 154a is slightly larger than the outer diameter of the thrust collar member 22. Lower thrust member 154 and upper thrust member 56
The upper thrust member 56 on the upper surface of the spacer portion 154a.
Are coaxially fitted and fixed to the inner peripheral surface of the large-diameter portion 52b in a state where the lower surfaces of the large-diameter portions 52b are stacked on the annular enlarged-diameter surface 52c. Then, the thrust flange member 22 is sandwiched between the inner peripheral upper surface (first thrust support portion) of the lower thrust member 154 of the rotating sleeve body 150 and the inner peripheral lower surface (second thrust support portion) of the upper thrust member 56. The thrust bearing portion 80 is configured.

In order to make the bearing clearance in the thrust bearing portion 80 appropriate, the axial distance between the inner peripheral upper surface of the lower thrust member 154 and the inner peripheral lower surface of the upper thrust member 56 is set to be equal to the vertical distance of the thrust flange member 22. In order to make the dimension appropriate for the axial direction between both surfaces, the vertical dimension of the spacer portion 154a may be made 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 180, and the inner diameter of the sleeve portion 52 a for the radial bearing portion 90 is determined by the outer diameter of the shaft member 20. Since it is sufficient if the dimensions are appropriate, the processing is easy.

The base plate 110 has an outer diameter smaller than that of the rotor hub 62 and does not have an annular recess with an upper opening. Further, the cap member 160 has an upwardly projecting cylindrical portion on its inner peripheral portion. Others are the same as those of FIG.

[0048]

The bearing device and the rotating machine according to the present invention hardly cause seizure in both the radial bearing portion and the thrust bearing portion, and effectively prevent the thrust bearing portion from being damaged or worn and the rotation accuracy from being reduced. Can come off.

The bearing device according to the second and third aspects and the rotating machine provided with the bearing device do not need to simultaneously satisfy the inner diameter of the sleeve portion and the axial size of the thrust flange portion. 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 a spindle motor provided with another 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 10a Lead-out hole 12 Annular concave part 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 Rotating sleeve body 52 Sleeve member 52a Sleeve portion 52b Large inner diameter portion 52c Annular expanded surface 54 Lower thrust member 56 Upper thrust member 58 Spacer member 60 Cap member 62 Rotor hub 62a Inward bulge 62b Outer bulge 64 Rotor yoke 66 Rotor magnet 80 Thrust bearing 90 Radial bearing part 110 Base plate 150 Rotating sleeve 154 Lower thrust member 154a Spacer part 160 Cap member 180 Thrust bearing part

Claims (5)

[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. And a sleeve member having a large inner diameter portion having an enlarged inner diameter. The sleeve portion is sleeve-fitted to a shaft portion to form a radial bearing portion, and the thrust flange is provided in the large inner diameter portion. A bearing in which a shaft portion and a sleeve member are rotatable relative to each other coaxially about their axis, wherein a first thrust support opposed in the axial direction is provided in the large inner diameter portion. A first thrust member and a second thrust member having a first portion and a second thrust support portion, respectively, are fixed to a sleeve member, and the thrust flange is provided between the first thrust support portion and the second thrust support portion. Shape is sandwiched The outer peripheral surface of the shaft portion and both surfaces in the axial direction of the thrust flange portion are harder than the inner peripheral surface of the sleeve portion, and both surfaces in the axial direction of the thrust flange portion are formed. A bearing device, wherein the first thrust support portion and the second thrust support portion are harder than the first thrust support portion. 2. One of the first thrust member and the second thrust member has a spacer portion projecting radially outward from the thrust flange portion toward the other thrust member and in contact with the thrust member. The bearing device according to claim 1, wherein the axial distance between the first thrust support portion and the second thrust support portion is determined by the axial dimension of the spacer portion. 3. A spacer member separate from the first thrust member and the second thrust member radially outward of the thrust flange portion is disposed, and the spacer member is provided in both axial directions of the spacer member. The surface is in contact with the first thrust member and the second thrust member, respectively, and the axial distance between the first thrust support portion and the second thrust support portion is determined by the axial size of the spacer member. 2. The bearing device according to 1. 4. The bearing device according to claim 3, wherein the linear expansion coefficient of the spacer member is larger than the linear expansion coefficient of the thrust flange. 5. A rotating machine provided with the bearing device according to claim 1, 2, 3 or 4.