JPH0754842A - Roller bearing - Google Patents

Abstract

PURPOSE:To surely give constant pre-load while shortening a fitting time by having a pre-load mechanism for dislocating positions of inner and outer rings relatively to each other along the axial direction with the utilization of a magnetic force built-in. CONSTITUTION:The fitting of a ball bearing 20 in a compact motor is completed by fixing a hole part 21b side of an inner ring 21 of the ball bearing 20 to a motor shaft and the outer peripheral surface side of an outer ring 22 to the sleeve side. When a motor shaft is rotated under such a condition, the inner ring 21 is rotated while a ball 23 is also rolled. The motor shaft is smoothly rotated while a radial load is supported by the sleeve through the ball bearing 20. Further, a first magnet plate 27 of a pre-load mechanism 26 is also then rotated together with the inner ring 21. On the other hand, the first and second magnet plates 27, 28 of the pre-load mechanism 26 generate repulsion repulsing each other. Thus, the inner ring 21 is dislocated from the outer ring 22 are can be rotated gently under the constant condition without generating noises and the deflection of the motor shaft.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to rolling bearings such as ball bearings and roller bearings, and more particularly to rolling bearings to which a preload is applied.

[0002]

2. Description of the Related Art FIG. 7 is a sectional view of a conventional small motor. In the figure, 1 is a motor shaft, and this motor shaft 1
A sleeve 3 is attached to the outer side of the sleeve via two rolling bearings 2. A supporting flange portion 4 is attached to an upper portion of the sleeve 3, and a stator 5 having a wire 5b wound around an iron core 5a is attached to a lower portion of the sleeve 3. A rotor yoke 6 in which a rotor magnet 7 is attached so as to face the stator 5 side is attached to a lower portion of the motor shaft 1. An output hub 8 having a chuck magnet 9 is attached to the upper portion of the motor shaft 1.

When an electric current is applied to the wire 5b of the stator 5, the rotor yoke 6 having the rotor magnet 7 rotates in a predetermined direction, and the motor shaft 1 rotates as the rotor yoke 6 rotates. With the rotation of the motor shaft 1, the hub 8 having the chuck magnet 9 rotates, and the rotational force of the motor shaft 1 is transmitted to the outside via the hub 8. In addition, 10 is a Hall element, 11 is an FG magnet,
Reference numeral 12 is an FPC board, 13 is a resistor, and 14 is a plate.

In this small motor, the rolling bearing 2 is preloaded in order to prevent the occurrence of shaft runout and noise, so that the rolling elements (for example, balls and rollers) in the bearing are prevented from rattling. ing.

Specifically, the side grooves 1a, 1a of the motor shaft 1 are
An adhesive is applied to the inside and the sleeve inner peripheral portions 3b and 3b. Then, the rolling bearings 2 and 2 are inserted in predetermined positions. Then, the motor shaft 1 is pressed in the direction of the arrow. This pressurization is performed for a time (for example, 4 minutes) for drying the adhesive with a force of 500 g, for example. As a result, the pair of rolling bearings 2,
The inner ring 2 is slightly displaced in the direction of the arrow from the outer rings of the pair of rolling bearings 2 and 2 mounted on the sleeve 3 side.
A preload is applied by the displacement between the inner ring and the outer ring, and rattling of the rolling elements arranged between the inner and outer rings is prevented.

[0006]

However, in the rolling bearing 2, the amount of preload is determined by the position of the inner ring which is positioned and fixed by the adhesive. For this reason, there is a problem that the set preload varies significantly due to a slight positional deviation of the inner ring. If this preload amount fluctuates, noise characteristics, motor characteristics (current consumption during no load, no load speed), and jitter characteristics of the small motor vary. In particular, when adhesion failure occurs in the inner ring, preload is hardly applied, which causes a fatal defect in the product.

Further, when pre-loading the rolling bearing 2, it is necessary to pressurize the inner ring for a time (4 minutes) for hardening the adhesive. For this reason, there is also a problem that the work time for assembling the rolling bearing 2 into the device becomes long.

On the other hand, when the rolling bearing 2 is mechanically preloaded without using an adhesive or the like, for example, the structure shown in FIG. 8 is used. That is, it is necessary to dispose the coil spring 15 between the convex portions 16a of the rotary shaft 16 and the inner ring 2a of the rolling bearing 2 and apply a preload to the inner ring 2a side by the coil spring 15. However, in this case, since the coil spring 15 for preload is arranged, the rotating shaft 16 becomes longer by that amount, which causes an inconvenience of increasing the size of the device.

In view of the above points, an object of the present invention is to provide a rolling bearing capable of reliably applying a constant preload, shortening the assembling time, and not increasing the size of the device. There is.

[0010]

According to the present invention, the above object is to provide a bearing having an inner ring fixed to the shaft side and an outer ring arranged outside the inner ring, and the positions of the inner ring and the outer ring. Is achieved by a rolling bearing having a built-in preload mechanism that relatively shifts along the axial direction by utilizing magnetic force.

In the present invention, preferably, the preload mechanism is
That is, it is configured to have a plurality of magnets that exert a magnetic force on each other.

Further, according to the present invention, preferably, the preload mechanism is composed of a plurality of magnetized portions which exert a magnetic force on each other.

Further, the present invention is preferably that the plurality of magnets or magnetized portions are arranged so as to exert repulsive force on each other.

[0014]

According to the above structure, the rolling bearing according to the present invention has the preload mechanism inside which the relative positions of the inner ring and the outer ring are relatively displaced, so that the rolling bearing is always preloaded. Therefore, if this rolling bearing is used, the assembly time of the device can be shortened. In this case, since the preload is applied by using the magnetic force, it is possible to reliably apply a constant preload. Further, since the preload mechanism is built in, the entire rolling bearing including the preload mechanism can be downsized.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described in detail below with reference to FIGS. It should be noted that the examples described below are suitable specific examples of the present invention, and therefore, various technically preferable limitations are given, but the scope of the present invention particularly limits the present invention in the following description. Unless otherwise stated, the present invention is not limited to these modes.

FIG. 1 shows a radial type ball bearing 20 which is an embodiment of the present invention. In FIG. 1, reference numeral 21 is a cylindrical inner ring in which an arc-shaped ring groove 21a is formed on the outer peripheral surface side and a shaft fixing hole portion 21b is formed on the inner peripheral surface side. Also, 22 is located outside the inner ring 21
And an arcuate ring groove 22a arranged concentrically with the inner peripheral surface side.
Is a cylindrical outer ring in which is formed.

A ring groove 21a between the inner ring 21 and the outer ring 22,
A plurality of balls 23, which are rolling elements, are arranged between the members 22a via a holder 24. This ball 23 is the inner ring 2
1 has a function of keeping the clearance space S between the outer ring 22 and the outer ring 22 at a constant value and smoothly rotating the inner ring 21 with respect to the outer ring 22. Ring-shaped seal members 25 are arranged on both sides of the ball 23 in the gap space S. This seal member 2
Reference numeral 5 is, for example, for preventing foreign matter from entering the ball 23 side, and the curved outer edge portion side is mounted in the inner groove of the outer ring 22.

On the upper side of the inner ring 21 and the outer ring 22, the upper end faces are flush with each other, but on the lower side, the outer ring 22 is the inner ring 2.
It is extended downward from 1 and a step portion is formed between the inner ring 21 and the outer ring 22. A preload mechanism 26 that displaces the positions of the inner ring 21 and the outer ring 22 relative to each other and eliminates rattling of the balls 23 is arranged at the position of this step. The preload mechanism 26 will be described below.

The preload mechanism 26 includes a first magnet plate 27 and a second magnet plate 27.
It is composed of a magnet plate 28 and a stop ring 29.
The first magnet plate 27 and the second magnet plate 28 are both disk-shaped magnets having holes 27a and 28a in the center, and the outer diameter of the first magnet plate 27 is slightly larger, but the inner diameters of both are larger. The dimensions are almost the same.

The first magnet plate 27 is positioned outside the lower end of the inner ring 21 concentrically with the inner ring 21, and the second magnet plate 2
8 is positioned concentrically with the outer ring 22 via a stop ring 29 inside the lower end of the outer ring 22. In this case, the first and second magnet plates 27 and 28 are arranged at a predetermined distance so as to face each other in the vertical direction, which is the axial direction of the inner ring 21 and the outer ring 22. Further, as shown in FIG. 2, the first and second magnet plates 27 and 28 have magnetic poles of the same polarity, for example, N poles, formed on the surface sides facing each other.

Here, the procedure for assembling the preload mechanism 26 will be described with reference to FIG. First, the hole 27a of the first magnet plate 27 is fitted into the step-like convex portion 21c formed on the outer peripheral portion of the lower end of the inner ring 21, and the first magnet plate 27 is press-fitted and fixed to the inner ring 21. Next, the outer edge of the first magnet plate 27 is inserted into the step groove 22b formed on the inner peripheral surface of the lower end of the outer ring 22. After that, when the stop ring 29 is press-compressed into the stop groove 22c in the step groove 22b and inserted, the assembling of the preload mechanism 26 to the inner ring 21 and the outer ring 22 side is completed.

Next, the operation when the above ball bearing 20 is used in a small motor will be described. FIG. 4 shows a ball bearing 20.
The cross section of the small motor using is shown.

When the hole 21b side of the inner ring 21 of the ball bearing 20 is fixed to the motor shaft 1 and the outer peripheral surface side of the outer ring 22 is fixed to the sleeve 3 side, the assembly of this ball bearing 20 into a small motor is completed. . In this state, if the motor shaft 1 rotates,
As the inner ring 21 rotates, the ball 23 also rotates.
The motor shaft 1 rotates smoothly while being supported by the sleeve 3 via the ball bearing 20 in the radial direction.
In this case, the first magnet plate 27 of the preload mechanism 26 is also the inner ring 2
Rotate with 1.

On the other hand, the first magnet plate 27 and the second magnet plate 28 of the preload mechanism 26 generate repulsive forces that repel each other.
Therefore, as shown in FIG. 1, the inner ring 21 to which the first magnet plate 27 is attached receives an upward force, and the second magnet plate 28
The outer ring 22 to which is attached receives a downward force.

That is, the preload is applied to the ball bearing 20, and the positions of the inner ring 21 and the outer ring 22 are relatively displaced in the vertical direction. Therefore, the ball 23 and the ring grooves 21a, 22 of the inner ring 21 and the outer ring 22 are formed.
Even if there is a gap with a, the ball 23 is pressed by the inner ring 21 and the outer ring 22.
3 No rattling occurs. Therefore, this ball bearing 20
By using, the motor shaft 1 rotates quietly in a constant state without noise or vibration of the motor shaft 1.

As described above, since the ball bearing 20 has the preload mechanism 26 of a simple structure incorporated therein,
A preload can be applied only by mounting the ball bearing 20 on the motor shaft 1 or the sleeve 3 side, and this small motor can be assembled in a short time. Further, since the structure of the preload mechanism 26 is simple, the preload mechanism 26 can be easily incorporated in the bearing and the preload mechanism 26 can be easily incorporated.
Also, the ball bearing 20 in which the above is incorporated does not increase in size. Therefore, the size of the device can be reduced as compared with the case where the preload mechanism is provided outside the bearing.

Further, in this preload mechanism 26, since a preload is applied by a magnetic force using a magnet, a constant preload can be applied to the ball bearing 20 easily and reliably. Therefore, unlike the conventional bearing in which the preload is applied by using the adhesive, there is no inconvenience that the magnitude of the preload varies greatly or the preload cannot be applied. In this case, the inner ring 2
The magnitude of the preload applied between the first magnet plate 27 and the outer ring 22 depends on the size of the gap between the first magnet plate 27 and the second magnet plate 28 and the magnitude of the magnetization amount of the first and second magnet plates 27 and 28. It can be easily changed by changing.

The opposing magnetic poles of the first magnet plate 27 and the second magnet plate 28 have different polarities, and the first and second magnet plates 2 are
Even if the suction force is generated in 7, 28, the preload can be similarly applied.

In the above embodiment, the outer ring 22 side is placed on the inner ring 2 side.
Although the preload mechanism 26 is provided on this step portion so as to be longer than the one side, conversely, the preload mechanism 26 may be provided on this step portion by making the inner ring 21 side longer than the outer ring 22 side.

Further, as shown in FIG. 5, instead of the first and second magnet plates 27 and 28, the cylindrical first and second magnet cylinders 3 having magnetic poles on the inner peripheral surface side and the outer peripheral surface side, respectively.
You may use 0,31. That is, the preload mechanism 260
Is the first magnet cylinder 3 attached to the outer surface of the lower end of the inner ring 21.
0, and a second magnet cylinder 31 that is concentric with the first magnet cylinder 30 but is attached to the inner surface of the lower end of the outer ring 22 in a state of being slightly displaced vertically. Even in this case, the positions of the inner ring 21 and the outer ring 22 are relatively displaced in the vertical direction due to the attractive force or the repulsive force generated between the first and second magnet cylinders 30 and 31, and the same effect as that of the above embodiment can be obtained. You can

Further, as shown in FIG. 6, a magnetized portion 32 is formed integrally with the inner ring 21 on the lower end outer surface of the inner ring 21, and a magnetized portion 33 is formed integrally with the lower end inner surface of the outer ring. Even when the preload mechanism 270 is configured by slightly shifting the magnetized portions 32 and 33 up and down, the same effect can be obtained.

Further, in the above embodiment, the ball bearing 20 having the balls 23 as the rolling elements has been described, but the same effect can be obtained also with the roller bearing in which the rolling elements are rollers. That is, the same effect can be obtained with a rolling bearing having rolling elements between the inner ring and the outer ring.

[0033]

As described above, according to the present invention, it is possible to provide a rolling bearing which can surely apply a constant preload, has a short assembling time, and does not cause an increase in the size of the device. You can

[Brief description of drawings]

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

FIG. 2 shows a first magnet plate and a second magnet plate in the preload mechanism of the ball bearing of FIG.
The figure which shows the direction of a magnetic pole with a magnet plate.

FIG. 3 is an explanatory view of an assembling procedure of the preload mechanism of the ball bearing of FIG.

4 is a sectional view of a small motor incorporating the ball bearing of FIG.

FIG. 5 is a sectional view around a preload mechanism of a ball bearing which is another embodiment of the present invention.

FIG. 6 is a cross-sectional view around a preload mechanism of a ball bearing which is another embodiment of the present invention.

FIG. 7 is a sectional view of a small motor incorporating a conventional rolling bearing.

FIG. 8 is a view showing a state in which a conventional rolling bearing is externally preloaded.

[Explanation of symbols]

 20 Ball Bearing 21 Inner Ring 22 Outer Ring 26 Preload Mechanism 27 First Magnet Plate 28 Second Magnet Plate 30 First Magnet Cylinder 31 Second Magnet Cylinder 32 Magnetization Part 33 Magnetization Part

Claims (4)

[Claims] 1. A bearing having an inner ring fixed to the shaft side and an outer ring arranged outside the inner ring, wherein the inner ring and the outer ring are positioned relative to each other in the axial direction by utilizing magnetic force. A rolling bearing characterized by having a built-in preload mechanism for shifting. 2. The rolling bearing according to claim 1, wherein the preload mechanism has a plurality of magnets that exert a magnetic force on each other. 3. The preload mechanism is composed of a plurality of magnetized portions that exert magnetic force on each other.
The rolling bearing according to claim 1. 4. The plurality of magnets or magnetized portions are arranged so as to exert a repulsive force on each other.
The rolling bearing according to claim 2 or 3.