Patent ID: 9243660
Filing Date: 2016-01-26
CPC Classification: F16C

Claim Text:
1. A main bearing for rotatably supporting a journal section of a crankshaft of an internal combustion engine, the journal section comprising a cylindrical body part, a lubricating oil path extending to penetrate the cylindrical body part, and two inlet openings of the lubricating oil path that are formed on an outer circumferential surface of the cylindrical body part, wherein the main bearing consists of a first half bearing and a second half bearing which are combined into a cylindrical shape by butting respective circumferential end surfaces, the first and second half bearings are configured to form an axial groove extending through an entire length of the main bearing in an axial direction on an inner circumferential surface side of each butting portion when the first and second half bearings are combined, each half bearing has a main cylinder portion including a central portion of the half bearing in the circumferential direction, and crush relief portions which are formed throughout an entire length of the half bearing in the axial direction at both end portions of the half bearing in the circumferential direction so that a wall thickness of the crush relief portion becomes thinner than that of the main cylinder portion, each crush relief portion extending from the end surface of the half bearing in the circumferential direction toward the central portion in the circumferential direction with a center angle not less than 3° and not more than 15°, each crush relief portion is formed by an outward protruding curved surface in a protruding shape protruding outward in the radial direction seen from the axial direction of the half bearing, a plurality of crush relief grooves extending in the circumferential direction through an entire length of the crush relief portion are formed in each crush relief portion to communicate with the axial groove, an oil groove is formed only on an inner circumferential surface of the first half bearing among the first and second half bearings, the oil groove extending in the circumferential direction through at least an entire length of the main cylinder portion of the first half bearing, and the second half bearing further has a transition region formed between at least the crush relief portion on a front side of the crankshaft in a rotation direction and the main cylinder portion such that a wall thickness of the transition region becomes thinner toward the crush relief portion from the main cylinder portion, the transition region comprising an inward protruding curved surface in a protruding shape protruding inward in a radial direction seen from the axial direction of the half bearing.