Honda Motor Co., Ltd.

Nichidai Corporation

Yasuhiro Ito

Takayuki Ohnuma

Tsutomu Ando

Yasuyuki Kondo

In a crankshaft, one holeL formed in a crankpinhas a bottom surface having a larger area and a depth from a surface of the crankpin less than those of another holeM. In forming the holeL and the holeM, a preformed productof the crankshaft having a shape smaller than that of a cavity is disposed in a die set and punches are simultaneously inserted into the crankpin. By this operation, the holeL and the holeM are simultaneously formed in each crankpinof the preformed product

Crankshaft and method for producing the same

A preformed product of a crankshaft is formed in a shape smaller than a shape of a cavity of a separatable die setcomposed of an upper die and a lower die and is disposed in the cavity of the die setas a material M. The cavity of the die setmatches a required shape of the crankshaft. When the material M is disposed in the cavity of the die set, a clearance is formed between the material M and the cavity, and when a side-forming punchP is inserted into the material M, a hollow hole is formed in the material M and the cavity is filled with the material M. As a result, not only can weight saving be achieved by forming the hole in the crankpin of the crankshaft, but also degradation of dimensional accuracy by forming the hole can be avoided.

Method for producing crankshaft and production apparatus therefor

The present invention provides a production apparatus for crankshaft, including: a die which has a lower die, an upper die, and plural side forming punches, the upper die being provided movably to the lower die, the side forming punches moving perpendicularly to a movement direction of the upper die; a press ram which moves the upper die to the lower die, closes a material of the crankshaft, and forms the material; cam mechanisms which are provided for the side forming punches and which move the side forming punches to an inside portion of the die in accordance with movement of the press ram; a grade separation structure which is provided to at least one of the side forming punches in order to prevent interference of the side forming punches with each other.

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Tochigi, Japan

Yasuhiro Ito