Toyoda Koki Kabushiki Kaisha

Naoki Ito

Shinji Soma

Toshiyuki Saito

Kazuhisa Sugiyama

Mamoru Katsuta

A grinding machine rotatably carrying a finish grinding wheel and a super-finish grinding wheel respectively on first and second wheel heads practices a method of grinding workpiece surfaces to super-finish surfaces with micro oil pockets. A surface of a workpiece rotatably carried on the machine is first ground with the finish grinding wheel to a predetermined diameter under the control of a sizing device. The workpiece surface is then ground with the super-finish grinding wheel to a target diameter under the control of a sizing device. The super-finish grinding is performed to the extent that peaks of a section curve representing the roughness of the workpiece surface attained by the finish grinding are removed but bottoms of the surface curve are left to a depth when the target diameter is reached, so that the bottoms so left of the roughness constitute the micro oil pockets.

Method and apparatus for grinding workpiece surfaces to super-finish surface with micro oil pockets

A crankpin of a crankshaft rotatably supports a big end of a connecting rod through a sliding bearing fitted therein. The sectional profile of the crankpin takes the form of a polygon whose profile is made of plural arcs of curvature. When the crankpin rotates relative to the bearing , the wedge effect is generated to decrease the squeeze loss, a kind of the power loss. And, the oil film thickness between the crankpin and the bearing is secured to prevent the shear loss, another kind of the power loss, from increasing, whereby the power loss can be decreased in total.

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Handa, Japan

Naoki Ito