JPH0214564B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The industrial application field of the present invention is the field of ceramic bearings that require two functions: wear 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, in the past, attempts have been made to improve wear resistance and corrosion resistance by using bearings made of oil-impregnated metal, plastic, or the like.

On the other hand, the bushing made of the above-mentioned material, which is fitted into the holder of the bearing part and is provided on the part that supports the rotating shaft, will rotate as the shaft rotates 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 a bushing are insufficient in terms of wear resistance and corrosion resistance when operating conditions are severe, such as in locations near the bottom of water. .

In addition, as a measure to prevent the bush from rotating, if a set screw or key is used, it is necessary to provide a screw hole or key groove in the bush or holder.
Furthermore, separate parts such as screws and keys are required, which increases the number of parts and makes machining extremely troublesome.

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

In other words, it is a bearing in which one rotary shaft is fitted and passed through each bushing provided in each holder of a plurality of bearings that are spaced apart from each other in the axial direction, and the bushing that supports the rotary shaft is inserted into the bushing. Made of ceramic, the central axes of the outer peripheral surface of the bushings are arranged offset from the central axis of the rotating shaft and the central axes of the inner peripheral surface of the bushings, and the central axes of the outer peripheral surfaces of the plurality of bushes are aligned with each other. Place them in a staggered manner.
In addition, a structure was adopted in which the rotating shaft was fitted into each bushing with the entire inner circumferential surface of each ceramic bushing in contact with the outer circumferential surface of the rotating shaft.

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

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

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

FIG. 1 explains a part of the first embodiment of the present invention. As shown in FIGS. 1A and 1B, a ceramic bush 1 has a rotary shaft 2 at an eccentric position.
It is bearing a bearing.

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

Here, the center of the outer peripheral surface of the bush 1 and the center of the inner peripheral surface of the holder 3, which is the holding part of the bush 1, are
If O ₁ is the center of the inner peripheral surface of the bush 1 which is the pivot support of the rotating shaft 2, and the center of the rotating shaft 2 is O ₂ ,
There is a distance of l between the two.

If such a structure is adopted, since the bush 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 bush 1. .

Furthermore, as shown in FIG. 1B, the center O 1 of the outer peripheral surface of the ceramic bush 1 is shifted by l from the center O ₁ of the inner peripheral surface of the bush 1 and the center O ₂ of the rotating shaft 2, so that each Even if the rotational trajectory of the bushings 1 is different and the bushing 1 attempts to rotate due to the rotation of the rotating shaft 2, the rotation of the bushing 1 is regulated and the co-rotation phenomenon does not occur.

In this way, the bush can be prevented from rotating without using a set screw, key, or the like.

FIGS. 2A to 2C illustrate an embodiment of the present invention using the components shown in FIGS. 1A and 1B, and the same parts as in FIG. 1 are designated by the same reference numerals.

If the center of the rotating shaft 1 is regulated by some means, the bearing will be 1 as shown in FIG.
Although it is possible to use a single bearing, if the center of the rotating shaft is determined only by this bearing, a structure in which it is held by two or more bearings is required.

However, if two or more bearings are provided in exactly the same arrangement as shown in FIG. 1, the rotating shaft will begin eccentric rotation about the center _O1 of the bush.

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

That is, for example, when two bearings are arranged, the centers of the left and right bushes 1, 1a are shifted relative to each other. It is desirable that the shifted state be in a completely opposite arrangement.

If such a structure is adopted, since the left and right bushes 1 and 1a mutually restrict their rotation, eccentric rotation will not occur, and the co-rotation phenomenon of the bushes 1 and 1a will not occur.

Incidentally, the fitting structure of the bush 1 is generally an interference fit structure, but thermal expansion between the bush 1, holder 3, and rotating shaft 2 may occur due to changes in ambient temperature conditions, heat generation during rotation of the shaft, etc. The difference in ratio 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 is formed on the outer peripheral surface of the ceramic bush 1, and is the same as the tapered surface 1b of the fitting groove 3a of the holder 3. It is a tapered surface with a slope of .

Then, the press plate 4 is fixed to the holder 3 on the large diameter side of the tapered surface 1b of the bush 1 with bolts 5, and a ring-shaped rubber or the like is formed between the press plate 5 and the bush 1, for example. Elastic members 6 are arranged.

When such a structure is adopted, since the fitting structure between the bush 1 and the holder 3 has a tapered structure, the fitting is performed reliably and no looseness occurs due to the wedge effect.

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

Note that in order to prevent backlash, it is best to increase the fit, but this only applies to materials with high ductility, such as ceramics, which have low ductility.
If the material is hard and brittle, increasing the interference fit will cause cracks during installation.

Further, ceramic has a small coefficient of thermal expansion, and a difference in thermal expansion occurs between the bush and the holder, and no matter how the tight fitting method is used, looseness will occur.
On the other hand, for the bush holding part shown in Fig. 3,
In the other embodiment shown in FIG. 4, the structure of the holding plate 4 is different.

That is, a ring-shaped projection 4a is projected toward the bush 1 from the side of the holding plate 4, which has a hole 4b for rolling through in the center thereof, and is brought into contact with the edge of the bush 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 a structure is adopted, the presser plate 4 is in direct contact with the bush 1 via the protrusion 4a,
Due to the presence of the elastic member 7, deformation of the bush, holder, etc. due to thermal expansion can be absorbed.

It can also absorb vibrations and prevent ceramic cracking.

In addition, in the embodiment shown in FIGS. 3 and 4,
Although the elastic members 6 and 7 are used directly or indirectly, a structure in which the press plate 4 directly presses the ceramic bush 1 may be adopted without using the elastic members 6 and 7.

[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. can significantly increase durability.

In addition, by arranging the central axes of the outer peripheral surface of each bushing to be offset from the central axis of the rotating shaft and the central axes of the inner peripheral surface of the bushing, the bushings tend to rotate as the rotating shaft rotates. The rotation locus can be made different from the rotation locus of the rotary shaft, and as a result, the bush can be reliably and easily prevented from rotating without using a separate member for preventing rotation, such as a screw or key.

Then, the center axes of the outer circumferential surfaces of a plurality of bushes provided in the axial direction of the rotating shaft are arranged so as to be offset from each other, and the mating surfaces of the inner circumferential surfaces of the ceramic bushes are brought into contact with the outer circumferential surface of the rotating shaft. By fitting the rotary shaft to each bushing in the state of As a result, eccentric rotation of each bushing does not occur, and the co-rotation phenomenon of each bushing can be prevented, so that all the bushings can be held even more reliably and easily to prevent them from rotating. You can leave it there.

As a result of these, a single rotating shaft that is fitted and passed through each bush provided in each holder of a plurality of bearings provided apart from each other in the direction of the bearing,
It can be rotated smoothly at all times without any problems.

Note that 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 drawings]

Figures 1A and B are a vertical sectional view and a side view showing a part of an embodiment of the present invention, and Figures 2A, B, and C are a side view, a longitudinal sectional view, and a right side view of an embodiment of the invention. The plan view, FIG. 3, and FIG. 4 are longitudinal cross-sectional views showing different structural examples of the bush holding portion in the present invention. 1, 1a...button, 1b...tapered surface, 2
... Rotating shaft, 3 ... Holder, 4 ... Holding plate, 4a
...Protrusion, 5...Bolt, 6, 7...Elastic member.

Claims (1)

[Claims] 1. A bearing in which one rotary shaft is fitted through each bushing provided in each holder of a plurality of bearings provided apart from each other in the axial direction, and the bushing that supports the rotary shaft is made of ceramic. The central axes of the outer peripheral surface of the bushing are offset from the central axis of the rotating shaft and the central axes of the inner peripheral surface of the bushing, and the central axes of the outer peripheral surface of the plurality of bushes are offset from each other. The ceramic bearing has a structure in which the rotating shaft is fitted into each bushing with the entire inner circumferential surface of each ceramic bushing in contact with the outer circumferential surface of the rotating shaft.