JPS61252918A - Locking device for ceramics bearing - Google Patents

Abstract

PURPOSE:To make a bearing keepable to the specified position in an accurate manner, by locking each extension part at both ends of an inner ring with a retaining ring, while maintaining the extent of clamping force with both ends of the inner ring. CONSTITUTION:A retaining ring 3 is locked to a shaft at both sides of a bearing 2. This retaining ring 3 is provided with an extension part 3a extending along an inner circumferential surface of a bearing inner ring 2a. After a ceramics bearing 2 is attached to a rotary shaft 1, when ambient temperature goes up, the shaft 1, the bearing 2 and the retaining ring 3 are all expanded in both axial and radial directions, but a convex part 3b runs on an incline at the outside of a V-shaped groove 2e of the inner ring 2. Therefore, this convex part 3b comes to clamp an outer end part of an inner ring 2b in consequence, so that initial clamping force is in no case reduced, thus the bearing is keepable to the specified position.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fixing device for a ceramic bearing suitable for use in high temperature, low temperature or other special environments.

[Conventional technology]

Ceramic bearings have recently come to be used in various fields because they have characteristics such as high heat resistance, wear resistance, corrosion resistance, chemical resistance, and high strength.

However, ceramic bearings generally have a smaller linear expansion coefficient than steel, so when installing a ceramic rolling bearing on a rotating shaft, it is not necessary to fix it with interference as is done with ordinary steel bearings. If this is done, when the environmental temperature rises during use, the dimensional difference between the bearing inner diameter and the shaft outer diameter will increase due to the linear expansion difference between the shaft material (made of steel) and the bearing (made of ceramics). It becomes even larger (the interference becomes larger), and as a result, an abnormally large tensile stress acts on the bearing, and in some cases, this alone may cause damage to the bearing. On the other hand, when the environmental temperature decreases, the interference becomes smaller, loosening the bearing and causing vibration.

As a solution to this problem, there is a method of providing a predetermined gap between the inner diameter of the bearing and the outer diameter of the shaft, a method of inserting an elastic body between the inner circumference of the bearing and the outer circumference of the shaft (Japanese Patent Application Laid-Open No. 57-6121), etc. was proposed.

[Problem that the invention seeks to solve]

However, when using these solutions to attach a bearing to a rotating shaft, if there is a gap or lack of support rigidity in the installation, abnormal vibration may occur during rotation, leading to early failure of the bearing. Needless to say. Similarly, even if the bearing is installed correctly at the time of assembly, if the accuracy of the installation deteriorates due to the environment in which it is used, it will result in the same unusable results as described above.

Therefore, the present invention provides the following advantages: 1. When installing a bearing on a rotating shaft, the installation does not require a clearance; 2. Installation errors can be minimized; and 3. Excessive stress may occur due to changes in environmental temperature. There are no gaps when installing the product, 4. There is no increase in installation errors due to changes in environmental temperature, and 5. It can be easily used under various environmental conditions. , aims to provide a fixing device for ceramic bearings.

[Means and effects for achieving the object] According to the present invention, there is provided a retaining ring in which the inner ring of the bearing is extended on both sides in the axial direction, and the outer circumferential surface and side surface of the extended portion are fixed to the rotating shaft, and its axially extending portion. When the environmental temperature changes, relative displacement occurs in the support part, and the shaft,
It absorbs the difference in thermal expansion caused by the expansion of the bearing inner ring and retaining ring,
The above problems can be solved.

〔Example〕

Hereinafter, the present invention will be explained in more detail based on embodiments shown in the drawings.

Figures 1a, b and c show an embodiment of the invention.

In the figure, reference numeral 1 denotes a rotating shaft made of steel, on which a bearing 2 is fixed. It consists of a bearing, an inner ring 2a and an outer ring 213 made of ceramic, and several balls 2c made of steel.

The diameter of the bearing inner ring 2a is slightly larger than the outer diameter of the shaft 1, so that the distance between the outer circumference of the shaft and the diameter of the inner ring becomes O at the expected maximum temperature. The inner ring 2a extends on both sides in the axial direction, and a V-shaped annular groove 2e is provided in each extension portion 2d.

On both sides of the bearing 2, retaining rings 3 are fixed to the shaft. The retaining ring 3 includes an extension portion 3a extending along the outer peripheral surface of the bearing inner ring 2a. The above-mentioned V is located inside the tip of the extension portion 3IL.
A convex portion 3b is provided that cooperates with the V-shaped groove, and the convex portion 3b is tightly fitted into the V-shaped groove when the bearing is mounted (at room temperature), as shown in Fig. 1. A tightening force is applied to the inner ring 2a, and the two retaining rings 3.3 push the bearing inner ring 2a from both sides to fix it in a predetermined position.

After the ceramic bearing 2 is attached to the rotating shaft 1, when the environmental temperature rises, the shaft 1, the bearing 2, and the retaining ring 3 expand in the axial and radial directions according to the linear expansion coefficients of the materials used. At this time, since the shaft 1 and the retaining ring 3 are made of steel, the expansion is relatively large. However, since the inner ring 2 is made of ceramics, its expansion is smaller than that of steel. That is, a difference in expansion occurs for each part. Therefore, since the retaining ring 3 is fixed to the shaft 1, it moves to the right together with the shaft (as shown in FIG. It moves upward and outward from the groove 2θ, and moves obliquely upward along the outer slope of the V-shaped groove. That is, the relative positions of each part at high temperatures are as shown in FIG.
It rides on the outer slope of the character-shaped groove 2e. In this state, the convex portion 3b will tighten the outer end of the inner ring 2b, so
The force does not decrease during the first tightening. In this case, an appropriate inclination angle θ of the V-shaped groove 2e, that is, the inclination angle θ at which the tightening force does not change before and after temperature changes, is expressed by the following equation.

Note that this retaining ring 3 can be divided into two parts, which makes assembly extremely easy.

Next, FIGS. 2a, b, and c show another embodiment.

This embodiment differs from the embodiment shown in FIG. 1 in that the bearing 2 is fitted to the shaft 1 with a gap, and retaining rings 3, 3 are attached to the shaft 1 on the side surfaces of both side extensions of the inner ring 2a. There is no place. However, the end of the axial extension 2d of the bearing inner ring 2a is a conical surface 2f with a small angle, whereas the axial extension 3a of the retaining ring 3 is flexible and has a radius R on its inner surface. A convex surface 3C is provided.

Therefore, when the bearing is fitted onto the shaft 1 and fixed on both sides by the retaining ring 3 as shown in FIG. Then, an elastic force is applied to tighten the axially extending portion 2d of the bearing inner ring, and the bearing 2 is fixed in a predetermined position by the retaining rings 3 on both sides. The extension portion 3C is in contact with the conical surface 2C at a portion near the end thereof.

When the environmental temperature rises, the retaining ring 3 moves away from the bearing inner ring 2a and expands radially outward at the same time.

The state is as shown in FIG. 2C. The retaining ring 3 comes into contact with the axially extending portion 2d of the bearing inner ring 2a at a portion near the tip of the extending portion 3a on the inner side than when assembled, but the tightening force remains unchanged. However, the retaining ring is separated from the side surface of the bearing inner ring 2a.

〔Effect of the invention〕

In the present invention, the bearing is fitted to the shaft with a gap, both ends of the inner ring are extended to both sides in the axial direction, and the extended portions are fixed to the shaft and fixed by a safety ring. However, the inner ring of the bearing will not be damaged by excessive tensile force, and even if the shaft and retaining ring expand, the tightening force on both ends of the inner ring will be maintained, so the ceramic bearing will always hold the specified position accurately. can do.

[Brief explanation of drawings]

FIG. 1a is a sectional side view of the main part of an embodiment of the present invention, the same (
b and c are enlarged cross-sectional side views showing the operation of the retaining ring during its installation and at high temperatures; Fig. 2a is a cross-sectional side view of main parts showing another embodiment, and Fig. 2a is the same (b)
, c is an enlarged cross-sectional side view showing the operation of the retaining ring during its installation and at high temperatures. 1... Rotating shaft 2... Bearing 2a... Bearing inner ring 2b... Bearing outer ring 2C... Pole 2d... Axial extension of inner ring 2e... Same
V-shaped groove 3...Retaining ring 3a...Same axial extension part 3b...Same convex part 3c...Same convex surface

Claims (3)

[Claims] (1) When the environmental temperature changes by extending the inner ring of the bearing on both sides in the axial direction and supporting the outer peripheral surface and side surfaces of the extended portion by a retaining ring fixed to the rotating shaft and its axial extension. a shaft that causes relative displacement in the support portion;
A fixing device for a ceramic bearing, characterized by absorbing the difference in expansion and contraction due to heat between the bearing inner ring and the retaining ring. (2) A patent claim in which the axially extending portion of the bearing inner ring has a V-shaped groove on the outer peripheral surface, and the axially extending portion of the retaining ring includes a convex portion that cooperates with the V-shaped groove. The device according to item 1. (3) A conical surface is formed on both ends of the outer peripheral surface of the axially extending portion of the bearing inner ring, and the axially extending portion of the retaining ring is flexible and includes a convex surface that cooperates with the conical surface. The device according to item 1.