TECHNICAL HELD

The present invention relates to a bearing member that is used as a sliding bearing, for example, at a rotational sliding part of an automobile engine.

BACKGROUND ART

One of conventional bearing members is disclosed in, for example, Patent Document 1. The bearing member disclosed in Patent Document 1 is used in, e.g., an internal-combustion engine of an automobile. This bearing member is a multi-layered sliding bearing that has an alloy overlying bearing layer with a thickness of 3 to 50 m on a surface of a copper alloy layer with specific degrees of coefficient of thermal expansion, thermal conductivity, and yield strength. This bearing member is made to have high followability to deformation of an aluminum alloy bearing housing and to have excellent heat dissipation.

CITATION LIST

Patent Document

Patent Document 1: JPH6-94037A

SUMMARY OF INVENTION

Technical Problem

However, in a case of using the conventional bearing member as described above, as a main metal or a connecting rod metal of an automobile engine, the bearing member comes into rotational sliding contact with a shaft body while receiving a load in an axial direction of a connecting rod, whereby the bearing member locally has a high-temperature region between the bearing member and the shaft body due to frictional heat and can cause a seizure due to the frictional heat. In particular, when an axial length is reduced as one of measures to reduce weight of an engine, such a bearing member tends to have a frictional force that increases in accordance with increase in surface pressure and to easily generate a seizure. For this reason, conventional bearing members are desired to be improved in seizure resistance.

The present invention has been made in view of the conventional circumstances, and an object of the present invention is to provide a bearing member having enhanced thermal conductive characteristics in directions along an inner circumferential surface of a shaft hole (directions including an axial direction and a circumferential direction) and thus having improved heat dissipation, whereby temperature rise due to rotational sliding contact with a shaft body is suppressed, and seizure resistance is improved.

Solution to Problem

The bearing member of the present invention includes a coating layer on an inner circumferential surface of a shaft hole into which a shaft body is to be fitted. The coating layer contains a metal base material and a heat conductive material that is dispersed in the base material and that has a thermal conductivity relatively higher than that of the base material. In this bearing member, the heat conductive material has a length in a direction along a surface of the coating layer, longer than a length in a thickness direction of the coating layer, and has a length in a circumferential direction of the shaft hole, longer than a length in an axial direction of the shaft hole.

Advantageous Effects of Invention

The bearing member of the present invention, which has the above-described structure, has enhanced thermal conductive characteristics in directions along the inner circumferential surface of the shaft hole, due to the coating layer formed by dispersing the heat conductive material in the base material. Thus, heat dissipation is improved, whereby temperature rise due to rotational sliding contact with the shaft body is suppressed, and seizure resistance is improved.

