Daido Metal Company Ltd.

Motohira Yamada

Osamu Ishigo

Yuichi Tomita

Kwangik Na

Shigeyoshi Mori

A cooling portion has an air inlet into which cooling air flows and is positioned in a preset range. When a distance from the upper to lower ends of an oil chamber in the axial direction of a rotating shaft member is h, and the shortest distance between an outer peripheral face of a casing and an inner peripheral face of a cover is a, the preset range is set in the following manner. Specifically, the preset range is set between &#xbc;h upward and 5/4h downward relative to the upper end of the oil chamber as a reference point, in the axial direction of the rotating shaft member. Additionally, the preset range is set between the outer peripheral face of the casing and relative to the outer peripheral face of the casing as a reference point, in the radial direction of the rotating shaft member.

Vertical bearing device

A main bearing for a crankshaft of an internal combustion engine is composed of a pair of semi-cylindrical bearings. An oil groove extending in a circumferential direction is formed on an inner circumferential surface of one semi-cylindrical bearing. The oil groove has the depth gradually decreasing toward a circumferential end surface of the one semi-cylindrical bearing, and defines a circumferential end portion on the circumferential surface without extending to an axial groove formed in a joint portion of the pair of semi-cylindrical bearings. An extension portion of the inner circumferential surface extends between the circumferential end portion and the axial groove, and a plurality of circumferential grooves extending in the circumferential direction is formed on the extension portion from the oil groove to the axial groove over an entire width of the circumferential end portion of the oil groove.

Main bearing for crankshaft of internal combustion engine

A main bearing for a crankshaft of an internal combustion engine comprises a pair of semi-cylindrical bearings. An oil groove extends on an inner circumferential surface of one semi-cylindrical bearing in a circumferential direction so that the center thereof in an axial direction aligns with that of an inlet opening of a lubricating oil path in a journal section of the crankshaft. The oil groove does not extend up to an axial direction groove formed at a joint portion of the semi-cylindrical bearings so that a separation inner circumferential surface extends between a circumferential direction end portion of the oil groove and the axial direction groove. The length of the separation inner circumferential surface is smaller than that of the inlet opening in the circumferential direction.

A bearing apparatus for a crankshaft of an internal combustion engine having a main bearing and a connecting rod bearing is provided. The main bearing comprises a pair of semi-cylindrical bearings, only one of which has an oil groove extending in a circumferential direction on an inner circumferential surface thereof. The oil groove is separated from an axial groove formed at a joint portion of the semi-cylindrical bearings by a separation inner circumferential surface of which a length Lin the circumferential direction is smaller than a length Lof an inlet opening of a journal portion in the circumferential direction. The connecting rod bearing also comprises a pair of semi-cylindrical bearings, and has axial grooves and crush reliefs with appropriate dimensions at joint portions thereof.

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Inuyama, Japan

Motohira Yamada