Main bearing for crankshaft of internal combustion engine

Abstract

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° to 15°. 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.

Description

BACKGROUND OF THE INVENTION[0001](1) Field of the Invention[0002]The invention of the present application relates to a main bearing for supporting a crankshaft of an internal combustion engine.[0003](2) Description of the Related Art[0004]A crankshaft of an internal combustion engine is supported at a journal section thereof by a cylinder block lower part of the internal combustion engine via a main bearing made of a pair of half bearings. For the main bearing, a lubricating oil that is discharged by an oil pump is fed into a lubricating oil groove that is formed along an inner circumferential surface of the main bearing through a through-port that is formed in a wall of the main bearing from an oil gallery that is formed in a cylinder block wall. Further, a first lubricating oil path is formed by being penetrated in a diameter direction of the journal section, and both end openings of the first lubricating oil path communicate with the lubricating oil groove of the main bearing. Fu...

AI Technical Summary

Benefits of technology

The patent text describes a main bearing for crankshafts of internal combustion engines. The design of the bearing has a high efficiency in removing foreign objects. The oil in the bearing has a high pressure in the gap between the bearing and the journal surface, which pushes the foreign objects towards the inner surface of the other bearing. This reduces the amount of foreign objects that enter the bearing and causes damage. The technical effect of the design is to improve the efficiency and lifespan of the main bearing in engines.

Problems solved by technology

Further, “the pressure of the oil which accompanies the journal surface and flows to the circumferential end portion side in the gap between the second curved surface and the journal surface>the pressure of the oil in the oil groove” is established, and the foreign matters are difficult to disperse while flowing to the gap between the second curved surface and the journal surface from the oil groove.

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