JPS61241521A - Ceramic bearing - Google Patents

Abstract

PURPOSE:To obtain a bearing which is excellent in wear-resistance and corrosion resistance, and eliminate the need of a whirl-stop by providing a bush made of ceramic, which is fitted to a holder of the bearing and supporting a rotary shaft, and disposing the bush and the rotary shaft in such a manner that the central axes thereof are shifted from each other. CONSTITUTION:A bush 1 made of ceramics is fitted to a holder 3. The holder 3 and the bush 1 forms a bearing portion. When the center of the bush 1 is O1, and the center of a rotary shaft 2 is O2, there is a distance l between both centers. In this structure, even if the bush 1 is about to be rotated by rotation of the rotary shaft 2, the rotation of the bush 1 is regulated not to cause follow ing rotation. Furthermore, the ceramic bearing is excellent in corrosion, wear- resistance and durability, and can be used without lubrication.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The industrial application field of the present invention is the field of ceramic bearings which are required to have two functions: II corrosion resistance and bearing rotation prevention.

[Prior Art] For example, various devices used underwater, such as a traveling screen, may have rotating shafts disposed underwater.

In such a case, foreign matter such as sand is likely to enter the bearing part of the shaft located particularly near the bottom of the water, and both the shaft and the bearing part may wear out.

Therefore, conventionally, bearings made of oil-impregnated metal, plastic, or the like have been used to improve dust resistance and corrosion resistance.

On the other hand, if the bushing made of the above-mentioned material is fitted into the holder of the bearing part and is provided on the part that supports the rotating shaft, the bushing itself will rotate with the rotation of the shaft if it is not fixed. A so-called co-rotation phenomenon occurs.

Therefore, in the past, items were fixed to the holder using a set screw, a key, or the like.

[Problems to be solved by the invention] However, bearings using oil-impregnated metal or plastic as bushings cannot be used under severe operating conditions, such as in locations near the bottom of water.
It was insufficient in terms of dust resistance and corrosion resistance.

J, T, Around the bushing 11 Second prevention 1: As a second countermeasure, if a set screw or key is used, it is necessary to install a screw hole or key groove in the bushing or holder, etc.
Since separate parts such as screws and keys were required, the number of parts increased and the machining was extremely troublesome.

[Means for Solving the Problems] In the present invention, the following measures were taken in order to solve the above-mentioned problems.

The bearing bushing is made of ceramic, which has excellent wear and corrosion resistance and can be used without lubrication.By shifting the center of the rotating shaft and the center of the bushing, the rotation locus of the shaft and bushing can be made different. , to prevent the simultaneous rotation of the bushings from occurring.

[Function] When ceramic is used as the bushing material, it can be used without lubrication, has excellent wear resistance and corrosion resistance, and can significantly increase durability.

Furthermore, by shifting the center of the rotating shaft and the center of the bushing, it is possible to completely separate the rotation stopper without using any special parts.

[Example] Hereinafter, the present invention will be described in detail based on an example shown in the drawings.

[First Embodiment 1] Figure 1 explains the first embodiment of the present invention.
As shown in Figures (A) and (B), a ceramic bushing 1 supports a rotating shaft 2 at an eccentric position.

A ceramic bushing 1 is fitted into a holder 3. The holder 3 and the bushing 1 constitute a bearing section.

Here, the center of the bushing 1 is 01, and the center of the rotating shaft 2 is O.
When the two are held back, the distance between them is Q.

If such a structure is adopted, since the bushing 1 is made of ceramic, it has excellent corrosion resistance and wear resistance, can be used without lubrication, and has excellent durability, so there is almost no need to replace the bushing 1. .

In addition, the center 01 of the ceramic bushing 1 and the center 0□ of the rotating shaft 2 shown in Fig. 1 (B) are Q. Even if bush 1 tries to rotate due to the rotation of bush 1, bush 1
rotation is regulated and co-rotation phenomenon does not occur.

In this way, the circumference of the bushing can be tightened without using a female thread or a key.

[Second Embodiment] FIGS. 2(A) to 2(G) illustrate a second embodiment of the present invention, in which the same parts as in FIG. 1 are given the same reference numerals.

If the center of the rotating shaft 1 is regulated by some means, even one bearing can be used as shown in Figure 1, but if the center of the rotating shaft is determined only by this bearing, requires a 171Ji structure that is held in place by two or more bearings.

However, if two or more bearings as shown in FIG. 1 are installed in exactly the same arrangement, the rotating shaft will start eccentrically rotating around the center 01 of the bushing.

Therefore, a structure as shown in FIGS. 2(A) to 2(C') is required.

That is, for example, when two bearings are arranged, the centers of the left and right bushings 1.1a are relatively shifted from each other. It is desirable that the shifted state be in a completely opposite arrangement.

If such a structure is adopted, the left and right bushings 1.1a
Since the rotation of the bushings 1.1a is mutually restricted, eccentric rotation does not occur, and the co-rotation phenomenon of the bushing 1.1a does not occur.

[Third Embodiment] By the way, the fitting structure of the bushing 1 is generally an interference fitting structure, but due to changes in ambient temperature conditions, heat generation during rotation of the shaft, etc., the bushing 1, holder 3, and rotating shaft 2 may The difference in thermal expansion coefficient between the two causes looseness in the fitting part.

In order to prevent the occurrence of such backlash, a structure as shown in FIGS. 3 and 4 may be adopted.

That is, in the example shown in FIG. 3, a tapered surface 1b of, for example, 5 to 10 degrees -6= is formed on the outer peripheral surface of the ceramic bush 1, and the fitting groove 3a of the holder 3 is formed on the tapered surface. 1b and 1b are tapered surfaces with the same slope.

Then, the presser plate 4 is fixed to the holder 3 on the large diameter side of the tapered surface 1b of the pusher 11 with bolts 5, and a ring-shaped rubber or the like is formed between the presser plate 5 and the bush 1. The elastic member 6 is arranged in the position 1.

If this J: Una structure is adopted, the bushing 1 and holder 3
Since the fitting structure has a tapered structure, the fitting is performed reliably and there is no play due to the wedge effect.

In addition, since the bushing 1 is pressed by the elastic member 6, even if the bushing 1, holder 3, shaft 2, etc. expand thermally, it can be absorbed. Measures can be taken to prevent cracking.

In addition, in order to prevent backlash, it is better to increase the interference fit, but this is true when the ductility is large.
In the case of materials such as ceramics, which have low ductility and are hard and brittle, if the interference fit is increased, cracks will occur during installation LJ.

Furthermore, ceramic has a small coefficient of thermal expansion, and a difference in thermal expansion occurs between the bushing and the holder, and no matter how the tight fitting method is used, looseness will occur.

[Fourth Embodiment] On the other hand, in another embodiment shown in FIG. 4, the structure of the push plate 4 is different.

That is, a ring-shaped projection 4a is projected toward the bushing 1 from the side of the holding plate 4, which has a hole 4b for transposition in the center thereof, and is brought into contact with the edge of the bushing 1.

Further, an elastic member 7 is elastically inserted between the head 5a of the bolt 5 and the outer surface of the holding plate 4.

When such an I4 construction is adopted, the presser foot 4 is in direct contact with the bushing 1 via the protrusion 4a, but due to the presence of the elastic member 7, deformation due to thermal expansion of the bushing, holder, etc. can be absorbed. can.

Further, it is possible to absorb photographic images, prevent cracking of ceramics 11-, etc.

In the embodiment shown in FIG. 3.4, the elastic member 6.7 is used directly or indirectly.
7, a structure may be adopted in which the ceramic bushing 1 is directly pressed by the presser plate 4.

Further, even when a tapered structure is adopted, it is of course possible to make the circumference of the bushing 1 if the center of the bushing and the center of the rotating shaft are shifted from each other, as in the forward-speed embodiment.

[Effects] As is clear from the above explanation, according to the present invention, since a ceramic bushing is used as the bushing fitted to the holder, it has excellent wear resistance and corrosion resistance, and can be used without lubrication. It can significantly increase durability! - can.

Furthermore, if the center of the ceramic bushing and the center of the rotating shaft are placed offset from each other, their rotation trajectories will be different, and rotation can be prevented without using separate members such as screws or keys.

In addition, if the bushing is mounted in a tapered structure and the bushing is pressed by a presser plate, the bushing can be fixed without wobbling.

[Brief explanation of the drawing]

Fig. 1 (A>, (B) is a vertical sectional view and side view showing a first embodiment of the present invention, Fig. 2 (A), (B), (C) is a second embodiment of the present invention. A left side view, a vertical cross-sectional view, a right side view, and FIGS. 3 and 4 are longitudinal cross-sectional views illustrating the third and fourth embodiments of the present invention and explaining structural examples with different sizes, respectively. 1.1a...button, 1b...tapered surface, 2...
・Rotating shaft, 3... Holder, 4... Holding plate, 4a...
-Protrusion, 5... Bolt, 6.7... Elastic member. Patent applicant: Ube Industries, Ltd. Figures 3 and 4

Claims (2)

[Claims] (1) A ceramic bearing in which the bush that is fitted into the bearing holder and supports the rotating shaft is made of ceramic, and the center axis of the bush is offset from the center axis of the rotating shaft. (2) When a plurality of ceramic bearings are used, the ceramic bearing according to claim 1, wherein the central axes of the bushes of at least two bearings are shifted from each other.