Daido Metal Company Ltd.

Ngk Spark Plug Company, Limited

Shinichi Sakurai

Seiji Amano

Toshitaka Honda

Takamitsu Mizuno

Akifumi Yamamoto

A main bearing for a journal portion of a crankshaft includes a pair of upper and lower half bearings forming a cylindrical shape. Each half bearing includes a main cylindrical portion including a circumferentially central portion and having a slide surface, and crush reliefs formed on both circumferential sides of the slide surface. Only the upper half bearing includes an oil groove on its inner peripheral surface, and an oil hole pierced from the oil groove to an outer peripheral surface. The lower half bearing includes an axial groove on the slide surface that is arranged apart from the circumferentially central portion toward the forward side by a circumferential angle of 10&#xb0; or more, and apart from the crush relief located on the forward side by a circumferential angle of 10&#xb0; or more.

Main bearing for crankshaft of internal combustion engine

A connecting rod bearing for a crankpin of a crankshaft of an internal combustion engine includes a pair of half bearings forming a cylindrical shape. Each half bearing has a main cylindrical portion including a circumferentially central portion of the half bearing, and crush reliefs formed on both circumferential sides of the main cylindrical portion with a wall thickness being smaller than that of the main cylindrical portion. At least one half bearing has an axial groove which extends in an axial direction on a slide surface of the main cylindrical portion, and is apart from the circumferentially central portion by a circumferential angle of 10&#xb0; or more toward a forward side in a rotation direction of the crankpin, and apart from the crush relief by a circumferential angle of 10&#xb0; or more toward the circumferentially central portion.

Connecting rod bearing for crankshaft of internal combustion engine

Provided is a semi-cylindrical-shaped half bearing having an inner surface including a center zone and end zones each including a plurality of recesses. Each recess includes a groove forming zone adjacent to the peripheral edge and including a plurality of circumferential grooves extending from the peripheral edge along the circumferential direction. An area ratio Sof an area of the groove forming zone to an area of the recess in the end zone is larger than an area ratio Sin the center zone. A maximum depth Dof the circumferential groove in the end zone is larger than a maximum depth Dof the circumferential groove in the center zone. A sliding bearing of the present invention includes the above half bearing.

Half bearing and sliding bearing

A half thrust bearing includes a sliding surface for receiving an axial force of a crankshaft of an engine, and a rear surface on an opposite side thereto. The sliding surface includes a flat surface portion near a circumferentially central portion, and two inclined flat surface portions on both circumferential sides of the flat surface portion. The axial distance between the rear surface and the sliding surface is maximum at the flat surface portion. At any radial positions, the axial distance in each inclined flat surface portion is maximum on a circumferentially central portion side and is reduced toward a circumferential end portion of the half thrust bearing. Each inclined flat surface portion is arranged to form one constant thickness portion extending linearly from a radially inner end to a radially outer end at a circumferential angle of 45&#xb0;.

Half thrust bearing

Provided is a semi-cylindrical shaped half bearing. The half bearing has an inner surface forming a sliding surface and including a plurality of recesses. Each recess has a smooth recess surface and a peripheral edge. The recess surface forms a convex curve toward the outer diameter side of the half bearing in cross-sectional view in a direction parallel to a circumferential direction of the half bearing. The recess includes a groove forming zone adjacent to the peripheral edge of the recess. The groove forming zone includes a plurality of circumferential grooves. The circumferential grooves extend from the peripheral edge of the recess along the circumferential direction of the half bearing. The present invention also provides a cylindrical sliding bearing including the above half bearing.

A half thrust bearing having a semi-annular shape includes a sliding surface for receiving an axial force of a crankshaft of an internal combustion engine, and a rear surface on an opposite side of the sliding surface, and defines a reference plane on the rear surface side that is perpendicular to an axial direction. The sliding surface includes a flat surface portion near a circumferentially central portion and in parallel with the reference plane, and inclined surface portions on both sides of the flat surface portion in a circumferential direction. At any radial positions of the half thrust bearing, an axial distance between the reference plane and the sliding surface is maximum at the flat surface portion, and is reduced in the inclined surface portions toward both circumferential end portions of the half thrust bearing.

A method for manufacturing an insulator for a spark plug is provided. The method includes: a preparing step; a press pin arranging step; a powder filling step after the press pin arranging step; a cavity blocking step after the powder filling step; a compression molding step after the cavity blocking step; a die releasing step after the compression molding step; and a press pin removing step after the die releasing step.

Growing community of inventors

Inuyama, Japan

Shinichi Sakurai