JPS6037466Y2 - bearing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a bearing, and particularly to a bearing including a bearing member made of ceramics.

In recent years, bearings using ceramics as bearing members, which have excellent heat resistance and wear resistance, have been used.

However, since ceramics have almost no elongation and have a coefficient of thermal expansion that is about one-third smaller than that of other structural members such as steel, there is the problem that bearing members may break when subjected to concentrated loads or thermal fluctuations. was there.

In view of these problems, the present invention aims to provide a bearing equipped with a bearing member made of ceramics, which is free from the risk of damage to the bearing member even when subjected to concentrated loads or thermal fluctuations.

In order to achieve this objective, the present invention divides a cylindrical bearing member made of ceramics in the circumferential direction, and forms a keyway between the divided ends on the circumferential surface of the bearing member opposite to the bearing surface. Then, the bearing member is attached to the mounting hole of the bearing body or the fitting support surface consisting of the outer peripheral surface of the shaft via the key fitted in the keyway, thereby distributing the concentrated load by displacement of each divided piece. Furthermore, the present invention provides a bearing in which the difference in thermal expansion between the bearing body and shaft and the bearing member made of ceramics when subjected to thermal fluctuations is absorbed by fluctuations in the gap generated at the split ends.

Furthermore, in the present invention, a gap is formed between the divided ends to an extent that does not impede the bearing function, and the gap has a coefficient of thermal expansion larger than that of structural members such as the bearing body and the shaft.
More preferably, a buffer member made of a material with a relatively small elastic modulus and high elongation is interposed, so that no gap is created between the divided ends of the bearing member even when subjected to thermal fluctuations.

A suitable example of the buffer member is a copper plate, and the buffer member is preferably set with an initial compressive force applied to the copper plate.

An embodiment of the present invention will be described below with reference to FIG. 1. Reference numeral 1 denotes a bearing body, and 2 a cylindrical bearing member made of silicon nitride ceramic. A mounting hole 3 as a surface is bored, and key grooves 4 are formed at three locations in the circumferential direction on the circumferential surface.

The bearing member 2 is divided into three parts in the circumferential direction corresponding to the keyway 4, and each divided end 5 is provided on the outer periphery of the bearing member 2.
A key groove 6 corresponding to the key groove 4 between a and 5b
is formed.

A key 7 is fitted into the space surrounded by the key grooves 4 and 6,
The bearing member 2 is attached to the bearing body 1 via the key 7.

Further, a gap δ is provided between each divided end portion 5a, 5b of the bearing member 2, and a buffer member 5 made of a copper plate is interposed in this gap δ, preferably with an initial compressive force applied thereto.

Reference numeral 2a denotes a bearing surface constituted by the inner periphery of the bearing member 2, and the shaft is rotatably supported by fitting into this bearing surface 2a.

In the above configuration, when the shaft is fitted and supported on the bearing surface 2a and installed in the device, a certain amount of clearance is always created between the inner periphery of the mounting hole 3 and the outer periphery of the bearing member 2, so a concentrated load acts. However, in this case, since each divided piece can be displaced, the concentrated load can be distributed even without deformation since the bearing member 2 is made of ceramics, and damage due to the concentrated load can be prevented.

Furthermore, when the bearing is exposed to heat, the shaft and the bearing body 1 thermally expand, increasing the shaft outer diameter and the mounting hole 3 inner diameter.On the other hand, since the bearing member 2 is made of ceramics, the increase in diameter due to thermal expansion will cause the shaft and bearing body 1 to expand thermally. Although it is smaller than the bearing body 1, this difference in diameter is absorbed by the increase in the gap δ between the divided ends 5a*5b of the bearing member 2, and the bearing member 2 is not damaged.

Further, the increase in the gap δ is compensated for by the thermal expansion of the buffer member 8 and the elastic elongation due to the release of the compressive force, so that the bearing member 2 does not wobble.

Note that when silicon nitride ceramics are used as the bearing member 2, the high-temperature strength is several orders of magnitude better than that of alumina ceramics.
It also has good thermal shock resistance, so it can withstand harsh usage conditions.

In the above embodiment, the bearing member 2 is attached to the bearing body 1 side, but the bearing member 12 may be attached to the outer peripheral surface of the shaft 11 as shown in FIG. The bearing shown in FIG. 2 may be assembled with the bearing shown in FIG.

In FIG. 2, 12a is a bearing surface on the outer periphery of the bearing member 12;
13 is a fitting support surface of the bearing member 12 formed on the outer periphery of the shaft 11, 14 is a keyway on the outer periphery of the shaft 11, 15a and 15b are divided ends of the bearing member 12, and 16 is formed between the inner peripheries thereof. 17 is the key fitted in the keyway 14.16, 18 is the gap δ between the split ends 15a and 15b.
This is a buffer member inserted into the

According to the bearing of the present invention, as is clear from the above explanation,
Since the bearing member is made of ceramic, it has excellent heat resistance and wear resistance, and since the bearing member is divided into multiple parts in the circumferential direction and attached to the mating support surface using keys, the bearing member and its mating support are Even if a concentrated load is applied to the bearing member due to a local gap between the bearing member and the surface, the bearing member displaces each divided piece, distributing the concentrated load, preventing damage caused by the concentrated load, and minimizing thermal fluctuations. Even if this occurs, the difference in thermal expansion between the structural member and the bearing member can be absorbed between the split ends, and damage to the bearing member can be prevented. Moreover, a gap is provided between the split ends, and this gap is filled with a material with a large coefficient of thermal expansion. Since the buffer member made of It is possible to eliminate all the drawbacks of bearing members made of ceramics and provide a heat-resistant, long-life bearing.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view of one embodiment of the present invention, and FIG. 2 is a longitudinal cross-sectional view of another embodiment. 1 is the bearing body, 2 and 12 are bearing members, 2a and 12a are bearing surfaces, 3 and 13 are fitting support surfaces, 4 and 6 degrees 14.16 are key grooves, and 5a, 5b, 15a, and 15b are split ends. ,7,1
7 is a key, 8 and 18 are buffer members, and 11 is a shaft.

Claims (1)

[Scope of utility model registration request] The cylindrical bearing members 2, 12 made of ceramics are divided into a plurality of parts in the circumferential direction, and the bearing surfaces 2a of the bearing members 2, 12,
The divided ends 5a, 5b, 15 are provided on the peripheral surface opposite to 12a.
Key grooves 6 and 16 are formed between a and 15b, and the bearing members 2 and 12 are attached to the fitting support surfaces 3 and 13 via keys 7 and 17 fitted in the key grooves 6 and 16, and the bearing members 2, 12 divided ends 5a, 5bg 15a+ 15
A bearing characterized in that a gap δ is provided between b and buffer members 8 and 18 made of a material with a large coefficient of thermal expansion are interposed in this gap δ.