JPH0626517A - Bearing device - Google Patents

Abstract

PURPOSE:To provide a bearing device having resistance against attractive force in the thrust direction and constituted thinly in one-stage structure by receiving a load in the thrust direction on a thrust bearing having balls therein while receiving a load in the radial direction on a radial bearing such as oil-retaining alloy bearing. CONSTITUTION:A bearing device comprises a thrust bearing 2 provided with balls 4, a fixed ring 5 having an end surface 5a for supporting one end of each ball 4 in the thrust direction and an inner circumferential ring 5b, and a rotary ring 6 having an end surface 6a for supporting the other end of each ball 4 in the thrust direction and an outer peripheral ring 6b; and a radial bearing 3 fixed to the inner circumferential ring 5b of the fixed ring 5 of the thrust bearing 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bearing device integrally provided with a thrust bearing which receives a load in the thrust direction and a radial bearing which receives a load in the radial direction, and is particularly suitable for use in a flat thin motor of a face-to-face type. Bearing device

[0002]

2. Description of the Related Art A conventional example of a face-to-face flat type thin motor will be described. First, the first conventional motor will be described with reference to FIG. The motor of the first conventional example, as shown in FIG.
It is composed of a rotor 21 and a stator 31. The rotor 21 is
A rotor magnet 22 magnetized in the surface direction is attached to a rotor yoke 23, and the rotor yoke 23 is attached to a rotary shaft 25 via a boss 24.

The stator 31 includes a coil 32, a back yoke 33 to which the coil 32 is attached, and a two-stage ball bearing 3 projecting from the center of the back yoke 33.
And a bearing housing 35 in which 4 is arranged. Rotor 21
Are rotatably supported by the stator 31 via ball bearings 34. The motor of the first conventional example is
Thus, the two-stage ball bearing 34 is used to support the rotor 21 with respect to the stator 31.

However, if the two-stage ball bearing is used, the cost of the ball bearing is high. Therefore, for the purpose of cost reduction, a second conventional motor shown in FIG. 6 has been proposed. In the motor of the second conventional example, the ball bearing 34 of one stage is unchanged, but the other stage is changed to an oil-impregnated alloy bearing 36. Furthermore, as the motor of the third conventional example, as shown in FIG. 7, the oil-impregnated alloy bearing 36 has only one stage, and the ball 37 is arranged in the center hole of the rotary shaft 25.
A structure has been proposed in which the oil-impregnated alloy bearing 36 receives a load in the radial direction and the ball 37 receives a load in the thrust direction.

Although three conventional techniques have been described above, if a magnet having a strong attracting force such as a rare earth magnet is used as the rotor magnet 22, there is a problem that the strong attracting force cannot be endured. Further, the bearing has a two-stage structure, and it is difficult to make it thinner. If you try to make it even thinner,
There was a problem that the accuracy of shaft run-out deteriorated.

[0006]

SUMMARY OF THE INVENTION The present invention has been proposed in view of the above problems of the prior art, and provides a bearing device that is strong against the attraction force of a rotor magnet and can be easily thinned. The purpose is to do.

[0007]

A bearing device of the present invention supports a ball, a fixed ring having an end surface for supporting one end of the ball in the thrust direction and an inner peripheral ring, and supports the other end of the ball in the thrust direction. It is characterized by comprising a thrust bearing having a rotating ring having an end face and an outer peripheral ring, and a radial bearing fixed to an inner peripheral ring of a fixed ring of the thrust bearing. Alternatively, a thrust including a ball, a fixed ring having an end surface supporting one end in the thrust direction of the ball and an inner peripheral ring, and a rotating wheel having an end surface supporting the other end in the thrust direction of the ball and an outer peripheral ring. It is characterized in that the bearing, the end surface of the fixed ring and the inner peripheral ring are made of an integral solid bearing material and a radial bearing bored in the inner periphery of the inner peripheral ring. Alternatively, the radial bearing is an oil-impregnated alloy bearing. Alternatively, the radial bearing is a hydrodynamic bearing. Alternatively, the radial bearing is a plastic bearing.

[0008]

As described above, the thrust bearing in the thrust direction receives the load in the thrust direction, and the radial bearing such as the oil-impregnated alloy bearing receives the load in the radial direction. Since it has a one-step structure, it can be made thinner.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the bearing device of the present invention will be described below with reference to the drawings, but it goes without saying that the present invention is not limited to this embodiment. The same components as those described in the related art are designated by the same reference numerals.

FIG. 1 shows a sectional view of a first embodiment of a bearing device 1 of the present invention. In FIG. 1, the bearing device 1 of the first embodiment comprises a thrust bearing 2 and a radial bearing 3.
The thrust bearing 2 includes a plurality of balls 4, a fixed ring 5 having an end face 5a supporting one end of the balls 4 in the thrust direction and an inner peripheral ring 5b, and an end face 6a supporting the other end of the balls 4 in the thrust direction. And a rotating ring 6 having an outer peripheral ring 6b.

The feature of the first embodiment is that the radial bearing 3 is fixed to the inner peripheral ring 5b of the fixed ring 5 of the thrust bearing 2. The thrust bearing 2 receives the load in the thrust direction, and the radial bearing 3 receives the load in the radial direction. The radial bearing 3 is composed of an oil-impregnated alloy bearing which is a sintered alloy, a hydrodynamic bearing such as a spiral groove bearing, or a plastic bearing having a low friction coefficient. In addition, 7 is a shield plate and 8 is a retainer.

An example in which the bearing device 1 of the first embodiment as described above is incorporated in a flat thin motor of a face-to-face type will be described with reference to the sectional view of FIG. In FIG. 2, the face-to-face flat motor includes a rotor 21 and a stator 31. Rotor 2
1, a rotor magnet 22 magnetized in the surface direction is attached to a rotor yoke 23.
Is fixed to the rotary shaft 25 via the boss 24, and the end surface 6 of the rotary wheel 6 of the bearing device 1 of the present invention is located near the center.
a is fixed.

The stator 31 comprises a coil 32 and a back yoke 33 to which the coil 32 is adhered, and the end surface 5a of the fixed ring 5 of the bearing device 1 of the first embodiment is located in the center of the back yoke 33. It is fixed.

The thrust direction load such as the attractive force of the rotor magnet 22 of the rotor 21 is applied from the rotor yoke 23 to the end faces 6a of the rotating ring 6 of the thrust bearing 2 of the bearing device 1 of this embodiment, the balls 4 and the end faces of the fixed ring 5. It is received by the back yoke 33 of the stator 31 via 5a. The rotary shaft 25 of the rotor 21 is rotatably supported by the stator 31 via the radial bearing 3 of the bearing device 1 of the present invention and receives a load in the radial direction.

As described above, the radial bearing 3 such as an oil-impregnated alloy bearing is fixed to the inner peripheral ring 5a of the fixed ring 5 of the thrust bearing 2 with the balls interposed between them by press fitting or caulking, and is integrated into a radial ring. The thrust composite bearing is used as a motor because the runout accuracy of the end face 6a (A face in FIG. 1) of the rotary wheel 6 can be suppressed based on the inner diameter of the radial bearing 3 (B portion in FIG. 1). The runout accuracy of the rotary shaft 25 and the rotor 21 at this time can be suppressed.

FIG. 3 shows a sectional view of a second embodiment of the bearing device 1a of the present invention. In FIG. 3, the bearing device 1a according to the second embodiment comprises a thrust bearing 2 and a radial bearing 3. The thrust bearing 2 includes a plurality of balls 4, an end surface 5a that supports one end of the balls 4 in the thrust direction, and an inner peripheral ring 5b.
A rotary wheel 6 having a fixed wheel 5 having an end surface 6a for supporting the other end of the ball 4 in the thrust direction and an outer peripheral wheel 6b.
And.

The feature of the second embodiment is that the end surface 5 of the fixed ring 5 is
The point a and the inner peripheral ring 5b are made of an integral solid bearing material, and the radial bearing 3 is provided on the inner periphery of the inner peripheral ring 5b. The thrust bearing 2 receives the load in the thrust direction, and the radial bearing 3 receives the load in the radial direction. The radial bearing 3
Is a hydrodynamic bearing such as an oil-impregnated alloy bearing which is a sintered alloy, a spiral groove bearing, or a plastic bearing having a low friction coefficient.

An example in which the bearing device 1a according to the second embodiment as described above is incorporated in a flat thin motor of a face-to-face type is shown in the cross-sectional view of FIG. 4, but the first embodiment described with reference to FIG. Since the structure is the same as that of the flat type thin motor of the surface facing type in which the bearing device 1 is incorporated, the description thereof will be omitted.

The feature of the bearing device 1a of the second embodiment is that the end surface 5a of the fixed ring 5 and the inner peripheral ring 5b are made of a solid bearing material, and the radial bearing 3 is formed on the inner periphery of the inner peripheral ring 5b. Has been drilled, so two parts become one,
Moreover, since the oil-impregnated alloy bearing and the plastic bearing can be easily produced by sintering or molding, the cost can be reduced with high accuracy. Since the runout accuracy of the end surface 6a of the rotary wheel 6 (A portion in FIG. 3) can be suppressed with reference to the inner diameter of the radial bearing 3 (B portion in FIG. 3), the rotary shaft 25 or The runout accuracy of the rotor 21 can be suppressed.

[0020]

As is apparent from the above description, the bearing device of the present invention thus receives the load in the thrust direction by the thrust bearing having balls interposed therein, and the load in the radial direction by the oil-impregnated alloy bearing or the like. By being received by the radial bearing, it is strong against the suction force in the thrust direction, and since the structure is a one-step structure, it can be made thinner. Moreover, by integrating the thrust bearing that receives the load in the thrust direction and the radial bearing that receives the load in the radial direction to improve accuracy, the shaft runout accuracy does not deteriorate due to misalignment of the upper and lower bearings when assembled in the motor. It is possible to improve accuracy.
Further, the bearing housing is not required, and the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a first embodiment of a bearing device of the present invention.

FIG. 2 is a cross-sectional view of an example in which the first embodiment of the bearing device of the present invention is incorporated into a flat type thin motor of a face-to-face type.

FIG. 3 is a cross-sectional view of a first embodiment of the bearing device of the present invention.

FIG. 4 is a cross-sectional view of an example in which the first embodiment of the bearing device of the present invention is incorporated in a flat type thin motor of a surface facing type.

FIG. 5 is a cross-sectional view of a first conventional example of a face-to-face flat motor.

FIG. 6 is a cross-sectional view of a second conventional example of a face-to-face flat motor.

FIG. 7 is a sectional view of a third conventional example of a surface-opposing flat motor.

[Explanation of symbols]

 1, 1a Bearing device of the present invention 2 Thrust bearing 3 Radial bearing 4 Ball 5 Fixed ring 5a End face supporting one end of the ball 5b Inner peripheral ring 6 Rotating ring 6a End face supporting the other end of the ball 6b Outer peripheral ring 7 Shield plate 8 Retainer 21 Rotor 22 Rotor magnet 23 Rotor yoke 24 Boss 25 Rotating shaft 31 Stator 32 Coil 33 Back yoke 34 Ball bearing 35 Bearing housing 36 Oil-impregnated alloy bearing 37 Ball

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location H02K 7/08 6821-5H

Claims (5)

[Claims] 1. A fixed wheel having a ball, an end surface supporting one end in the thrust direction of the ball and an inner peripheral ring, and a rotating wheel having an end surface supporting the other end in the thrust direction of the ball and an outer peripheral ring. A bearing device comprising: a thrust bearing provided; and a radial bearing fixed to an inner peripheral ring of a fixed ring of the thrust bearing. 2. A fixed wheel having a ball, an end surface supporting one end in the thrust direction of the ball and an inner peripheral ring, and a rotating wheel having an end surface supporting the other end in the thrust direction of the ball and an outer peripheral ring. A bearing device comprising: a thrust bearing provided; and a radial bearing formed on an inner periphery of the inner peripheral ring, wherein the end surface of the fixed ring and the inner peripheral ring are made of an integral solid bearing material. 3. The bearing device according to claim 1, wherein the radial bearing is an oil-impregnated alloy bearing. 4. The bearing device according to claim 1, wherein the radial bearing is a hydrodynamic bearing. 5. The bearing device according to claim 1, wherein the radial bearing is a plastic bearing.