JPH05308745A - Spindle motor - Google Patents

Abstract

PURPOSE:To make it possible to put an inner ring uniformly under pressure in an axial direction when a bearing member is fixed to stationary and rotary members in an assembling step, in which a pre-load can be applied easily even when an end of an axle member is not projected from the lower end face of the inner ring, and a load can be applied before a slow-active adhesive is cured. CONSTITUTION:In a spindle motor assembling step, an elastic member 7 is provided between a rotary member 1 and a bearing member 6 out of bearing members 5 and 6, and another bearing member 5 and an end face of a shaft member 4 are supported by using a pressing plate member 8. Then, pre-loads are applied to an inner ring 62 in the bearing member 6 and to an inner ring 52 in the bearing member 5 through the elastic member 7 or the pressing member 8, and then the bearings 5 and 6 are fixed in position between a stationary member 2 and the rotary member 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spindle motor which preliminarily positions a bearing member at a fixed position and applies a preload thereto.

[0002]

2. Description of the Related Art Conventionally, in a spindle motor or the like for rotationally driving a recording medium such as an optical / magnetic disk, vibration or noise that causes a read / write error on the recording medium is suppressed as much as possible. Therefore, a pair of radial type ball bearings are arranged in series along the shaft member. And, with the axial spacing of this pair of ball bearings constant,
A fixed position preloading method is employed in which the inner and outer races are fixed by applying a predetermined load to the inner and outer races, which are opposed to each other in the axial direction.

FIG. 3 shows a conventional spindle motor having a fixed position preload type bearing.

This spindle motor is a shaft rotation type spindle motor in which a hub and a shaft member are integrally formed.

Of the pair of ball bearings 105 and 106, the stationary member 10 corresponding to the outer ring 106a of the upper ball bearing 106.
2, the inner ring 106b is fixed to the shaft member 104 by adhesion or press fitting. Next, the outer ring 10 of the lower ball bearing 105
The outer peripheral surface of 5a and the stationary member 102 are bonded with a fast-acting adhesive, the inner peripheral surface of the inner ring 105b and the shaft member 104 are bonded with a slow-acting adhesive, and a load is applied to the inner ring 105b by using a cylindrical pressing member 108. Pressurize. Then, the inner ring 1 of the lower ball bearing 105
05b is pushed upward from the pressing member 108,
The inner ring 106b of the upper ball bearing 106 is pushed downward by a protrusion 104a provided at the base of the shaft member 104, and is fixed to the stationary member 102 and the shaft member 104 with a preload applied to both bearings 105 and 106. To be done. As a result, the rotational accuracy of the radial type ball bearing is increased, and vibration and noise are suppressed.

[0006]

However, the pressing member used for applying this type of load is not necessarily pressed in the axial direction, and the bearing corresponds to a member in which the preload is not evenly applied to the side surface of the inner ring. It was fixed on the sheet, and substantially sufficient rotation accuracy could not be obtained.

In particular, when the shaft member projects outward from the end surface of the bearing located outside in the axial direction, the pressing member of the pressing member is pressed along the shaft member so that the pressing portion of the pressing member has an inner ring portion of the bearing. However, if the end face of the bearing and the end face of the shaft member located on the outside in the axial direction are on the same plane, the pressing member contacts the inner ring portion of the bearing and at the same time the end face of the shaft member is contacted. However, there was a problem that preload could not be applied to the inner ring of the bearing.

Further, a slow-acting adhesive was used between the inner ring of the bearing and the member corresponding to the inner ring, and the load was applied before the adhesive was hardened. However, in reality, before applying the load. In some cases, sufficient preload could not be applied to the bearing even though hardening started and a predetermined load was applied.

The present invention has been made in view of the above facts, and the main purpose thereof is to apply a load for the fixed position preload before the slow-acting adhesive is hardened so that the load can be applied. Even if the end face of and the end face of the shaft member are located in the same plane,
(EN) Provided is a spindle motor having a structure capable of easily and surely applying a preload to an inner ring of a bearing.

[0010]

In order to achieve the above-mentioned object, in a spindle motor of the present invention, an elastic member is provided between at least one of a pair of bearing members and a stationary member and / or a rotating member. The bearing member is fixed to the stationary member and / or the rotating member by applying a preload to the inner ring portion or the outer ring portion of the bearing member.

[0011]

According to the above spindle motor, since the elastic member is internally provided between the bearing member and the stationary member and / or the rotating member, a preload is applied when the bearing member is inserted into the shaft member. If the end surface of the inner ring of the bearing positioned on the outer side in the axial direction and the end surface of the shaft member are supported in the same plane, the elastic member can evenly press the inner ring of the bearing on the inner side in the axial direction, and A preload can be applied to.

[0012]

1 is a sectional view of a spindle motor according to the present invention. Reference numeral 1 is a hub as a rotating member, and 2 is a bearing holding member as a stationary member. Reference numerals 5 and 6 denote a first ball bearing and a second ball bearing which are interposed between the hub 1 and the bearing holding member 2 to rotatably support the hub 1 relative to the bearing holding member 2. is there.

The hub 1 is formed of stainless steel and has a substantially cup shape. The hub 1 has a cylindrical portion 1a on which a magnetic disk 90 is mounted, and one end surface (upper end portion in FIG. 1) of the cylindrical portion 1a. The clamp holding portion 1b, which is positioned and corresponds to the bottom portion of the cup shape, and the disc mounting portion 1c, which has a flange shape and is expanded at the other end (the lower end portion in FIG. 1) in the radial direction from the outer diameter of the cylindrical portion 1a. ..

A magnetic disk 90 as a recording member is mounted on the disk mounting portion 1c and has a ring-shaped spacer 91.
A plurality of magnetic disks 90 are stacked via the. The stacked magnetic disks 90 are pressed and fixed from above by a clamp member 92.

A cylindrical rotor magnet 35 is arranged on the inner peripheral portion of the cylindrical portion 1a.

On the other hand, a shaft member 4 formed integrally with the hub 1 is provided at the center of the clamp holding portion 1b so as to project in the axial direction toward the open end side of the hub 1.

The bearing holding member 2 has a cylindrical base portion 20, an inward projecting portion 21 projecting over the entire circumference in the center portion on the inner peripheral side of the base portion 20, and a small amount at one end portion of the base portion 20. And a stator fixing portion 22 protruding outward.

Both members are arranged close to each other between the stator fixing portion 22 and the clamp holding portion 1b of the hub 1 to form a narrow space portion 11. The space 11 has a labyrinth structure that makes it extremely difficult to ventilate the inside and the outside of the motor and prevents outgas such as lubricant generated from the second ball bearing from scattering into the disk chamber.

The stator 3 is inserted from the end of the bearing holding member 2 opposite to the stator fixing portion 22, and the stator fixing portion 2 is inserted.
It is adhesively fixed at a position where it abuts 2. Stator 3
Is composed of a stator core 31 and a stator coil 32 wound around the stator core 31, and is arranged so as to face the rotor magnet 35. And the stator coil 32
When the energization is started, the hub 1 and the shaft member 4 formed integrally with the hub 1 rotate relative to the bearing holding member 2 which is a stationary member due to electromagnetic interaction between the stator 3 and the rotor magnet 35. To do.

The inward projecting portion 21 has the hub 1 rather than the stator 3.
Is provided near the open end of the shaft member 4 and is located at the center of the shaft member 4.

The inner surface of the base portion 20 located below the lower surface 21b of the inward projection 21 is the lower outer ring fixing surface 20b, and the inner surface of the base portion 20 located above the upper surface 21a is the upper outer ring fixing surface. 20a.

The outer ring 51 of the first ball bearing 5 is adhered to the lower outer ring fixing surface 20b in a state where the upper end surface 51a of the outer ring 51 is in contact with the lower surface 21b of the inward projecting portion 21, and the outer ring 51 of the second ball bearing 6 is The lower end surface 61 b of the outer ring 61 is the upper surface 2 of the inward protruding portion 21.
The upper outer ring fixing surface 20a is adhered to the upper outer ring fixing surface 20a while being in contact with the first outer ring 1a.

The inner ring 52 of the first ball bearing 5 is fixed to the lower inner ring fixing surface 4b of the shaft member 4 by using a relatively quick-curing adhesive, and the inner ring 62 of the second ball bearing 6 is the upper part of the shaft member 4. It is fixed to the inner ring fixing surface 4a using an adhesive agent that cures relatively slowly.

An elastic member 7 is mounted between the inner ring upper end surface 62a of the second ball bearing 6 and the clamp holding portion 1c of the hub 1.

The elastic member 7 has two disc springs 71 and 72 fixed to the outer periphery so as to have elasticity in the inner diameter. The upper disc spring 71 of the elastic member 7 abuts on the root ends of the clamp holding portion 1c of the hub 1 and the shaft member 4, and the lower disc spring 7
2 contacts the upper end surface 62a of the inner ring of the second ball bearing 6
The inner ring 62 of the ball bearing 6 is pressed downward in the axial direction.

At this time, the inner ring lower end surface 52 of the first ball bearing 5
If b and the end face 42 of the shaft member 4 are fixed by the pressing member 8, the elastic force of the elastic member 7 causes both ball bearings 5, 6
It can be fixed in place with a preload applied to.

Next, an embodiment as a modification of the spindle motor will be described.

In the spindle motor shown in FIG. 1, the hub 1 and the shaft member 4 are integrally formed, but in this example, the hub 1
And the shaft member 4 is a separate spindle motor.

The names and numbers of the spindle motors are as shown in FIG.

The outer ring 51 of the first ball bearing 5 and the outer ring 61 of the second ball bearing 6 are bonded to the inner circumference of the bearing holding member 2,
The shaft member 4 is inserted from the second ball bearing 6 side. The inner ring 52 of the first ball bearing 5 is bonded with a press-fitting or quick-acting adhesive, and the inner ring 62 of the second ball bearing 6 is bonded with a slow-curing adhesive.

After the pressing member 8 is abutted on the end surface 42 of the shaft member 4 and the inner ring lower end surface 52b of the first ball bearing 5,
The elastic member 7 is mounted on the inner ring upper end surface 62a of the second ball bearing 6.

Finally, the hub 1 is press-fitted into the shaft member 4, and the elastic force of the elastic member 7 applies a preload to the inner ring 62 of the second ball bearing 6.

In another assembly method, the first ball bearing 5
The outer ring 51 and the inner ring 52 are bonded or press-fitted to the bearing holding member 2 and the shaft member 4, respectively. Then, the inner ring 62 of the second ball bearing 6 and the shaft member 4 are bonded with a slow-curing adhesive, and the outer ring 61 and the bearing holding member 2 are bonded with a fast-curing adhesive. The elastic member 7 may be attached to the inner ring upper end surface 62a of the second ball bearing 6 and the hub 1 may be press-fitted into the shaft member 4.

As another embodiment, as shown in FIG. 2, an enlarged diameter portion 241 is provided in the central portion of the shaft member 204.

First, the inner ring upper end surface 2 of the first ball bearing 205
52a is the lower end surface 241 of the expanded diameter portion 241 of the shaft member 204.
The shaft member 204 is adhered or press-fitted so as to be abutted on a. The outer ring 251 is bonded to the bearing holding member 202.

Next, the second ball bearing 206 is attached to the shaft member 204.
And the bearing holding member 202, and the inner ring 262 and the shaft member 204 are bonded with a slow-curing adhesive, and the outer ring 261 and the bearing holding member 202 are bonded with a fast-curing adhesive. The elastic member 207 is attached to the inner ring upper end surface 262a of the second ball bearing 206, and the hub 201 is press-fitted into the shaft member 204.

If this structure is used, the processing of the shaft member 204 becomes complicated, but it is not necessary to use a pressing member, and the end surface 242 of the shaft member 204 projects beyond the inner ring lower end surface 252b of the first ball bearing 205. However, the preload can be added easily.

Although one embodiment of the spindle motor according to the present invention has been described above, the present invention is not limited to this embodiment, and various variations and modifications can be made without departing from the scope of the present invention. is there.

For example, although the spindle motor of this embodiment is of the shaft rotation type, it may be of the shaft fixed type.

The inner ring upper surface 62a of the second ball bearing 6
The elastic member 7 is abutted on the inner ring 62, and an adhesive having a relatively slow curing is used for the inner ring fixing surface 4a of the inner ring 62. However, the bearing holding member 2 is not provided with the inward protruding portion 21, and the two inner ring fixing surfaces 4a are not provided. 4b and the outer ring 51 of the first ball bearing 5 are bonded with an adhesive that cures relatively quickly, and the outer ring 61 of the second ball bearing 6 is bonded with an adhesive that cures relatively slowly. May be configured to act on the outer ring 61 of the second ball bearing 6.

[0041]

According to the spindle motor of the present invention,
Since an elastic member is interposed between the shaft member and the bearing to apply a preload to the bearing and fix the bearing at a fixed position, the preload can be applied reliably and easily.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a sectional view showing another embodiment according to the present invention.

FIG. 3 is a cross-sectional view showing a conventional technique.

[Explanation of symbols]

 1 hub 2 bearing holding member 3 stator 4 shaft member 5 first ball bearing 6 second ball bearing 7 resilient member 8 pressing member 35 rotor magnet

Claims (1)

[Claims] 1. A stationary member, a rotating member which is rotatable relative to the stationary member, and an interposition between the stationary member and the rotating member, which is positioned in advance at a fixed position in the axial direction. And a pair of bearing members to which a preload is applied, a resilient member is provided between at least one of the pair of bearing members and the stationary member and / or the rotating member. A spindle motor, characterized by being internally mounted and applying a preload to an inner ring portion or an outer ring portion of the bearing member to fix the bearing member to the stationary member and / or the rotating member.