Daido Metal Company Ltd.

Yuki Kawashima

Motohiko Koushima

Kenta Kato

A main bearing includes first and second half bearings, each having a main cylinder portion and crush relief portions in both circumferential end portions. An oil groove circumferentially extends on an inner circumferential surface only of the first half bearing, one circumferential end portion of the oil groove opens on a circumferential end surface on a front side in a rotation direction, and the other circumferential end portion of the oil groove is positioned in the crush relief portion on a rear side in the rotation direction. The first half bearing includes a transition region between the crush relief portion on the front side in the rotation direction and the main cylinder portion, and the second half bearing includes a transition region between the crush relief portion on the rear side in the rotation direction and the main cylinder portion.

Main bearing for crankshaft of internal combustion engine

A main bearing includes first and second half bearings, each having a main cylinder portion and crush relief portions in both circumferential end portions. An oil groove circumferentially extends on an inner circumferential surface only of the first half bearing, one circumferential end portion of the oil groove opens on a circumferential end surface on a front side in a rotation direction, and the other circumferential end portion of the oil groove is positioned in the main cylinder portion. The first half bearing includes a transition region at least between the crush relief portion on the rear side in the rotation direction and the main cylinder portion, and the second half bearing includes a transition region at least between the crush relief portion on the front side in the rotation direction and the main cylinder portion.

A main bearing for a crankshaft of an internal combustion engine has first and second half bearings forming an axial groove on an inner circumferential surface of a butting portion. Each half bearing has a main cylinder portion including a central portion, and crush relief portions each extending toward the central portion from an end surface of the half bearing with a center angle of 3&#xb0; to 15&#xb0;. A plurality of crush relief grooves are formed in each crush relief portion in the circumferential direction to communicate with the axial groove. An oil groove is formed in the circumferential direction on an inner circumferential surface of the first half bearing. The second half bearing has a transition region having an inward protruding curved surface a wall thickness of which becomes thinner toward the crush relief portion from the main cylinder portion.

A main bearing for a crankshaft of an internal combustion engine has first and second half bearings forming an axial groove on an inner circumferential side of a butting portion. Each half bearing has a main cylinder portion including a central portion in a circumferential direction, and crush relief portions each extending toward the central portion from an end surface of the half bearing in the circumferential direction with a center angle of 3&#xb0; to 15&#xb0;. A plurality of crush relief grooves are formed in each crush relief portion to extend in the circumferential direction and communicate with the axial groove. The first half bearing has an oil groove extending in the circumferential direction and a transition region having an inward protruding curved surface with a wall thickness becoming thinner toward the crush relief portion from the main cylinder portion.

A connecting rod bearing fort supporting a crankpin of an internal combustion engine is provided. The crankpin has a discharge port on its surface for supplying lubrication oil to a gap between the crankpin and the connecting rod bearing constituted by a pair of half bearings. The half bearing includes a main cylindrical portion, crush reliefs and transitional regions. A plurality of crush relief grooves are formed in the crush relief to continuously extend in a circumferential direction, and an axial groove is formed at an inner side end edge of the half bearing in the circumferential direction to continuously extend in an axial direction so that the crush relief grooves communicate with the axial groove.

Connecting rod bearing

According to the invention, there is provided a connecting rod bearing constituted by a half bearing, which has a main cylindrical portion, crush reliefs and a transitional region. The crush relief is formed so that a depth from a virtual inner circumferential surface at a position of an end surface of the half bearing in a circumferential direction is larger than a depth from the virtual inner circumferential surface at a position where the crush relief connects with the transitional region. Further, a plurality of circumferential grooves are provided in the main cylindrical portion to continuously extend in the circumferential direction throughout an entire length of the main cylindrical portion in the circumferential direction, and are continuously provided also in the transitional region.

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Inuyama, Japan

Yuki Kawashima