Honda Giken Kogyo Kabushiki Kaisha

Ryuji Soga

Shuichi Yamane

Hiroshi Sugita

Kimio Momose

Yoshiro Akiyama

Hisayuki Sakurai

Tadatomo Hatayama

Shigehisa Seya

Takashi Asada

Seiichi Akimoto

Takashi Kihara

Kenichia Hakozaki

Nobuaki Hojo

Yousuke Yamazaki

A preform for a connecting rod of an engine is manufactured with a good productivity. The preform has a large-end mass portion which corresponds to a large-end portion of the connecting rod, a small-end mass portion which corresponds to a small-end portion thereof, and a shaft portion which corresponds to a rod portion thereof. There is manufactured a preform blank which has a shaft-shaped portion which is formed by extrusion. This shaft-shaped portion is made up of the shaft portion and an extended portion which extends axially forward from the shaft portion. The small-end mass portion is formed by squeezing the extended portion in the axial direction in a plurality of times starting with a portion near the shaft portion.

Method of manufacturing preform for connecting rod

A connecting rod is formed by cold forging in a single pressing cycle at a good accuracy without separately preparing a large-end cap, to thereby reduce the manufacturing cost. A double-action type of forging apparatus is made up of an upper die, a lower die, and a large-end portion punch and a small-end portion punch, both being movably provided in each of the dies. The upper die is closed to the lower die while forging a preform, to thereby roughly form a connecting rod. Then, the large-end portion punch and the small-end portion punch are protruded into a forming space between both the upper and lower dies to forge the parts to be pierced, thereby filling underfilled parts with material. Then, the large-end portion punch and the small-end portion punch on the side of the upper die are pushed out of the forming space to reach the lower die. The underfills left in the parts to be pierced are blanked or punched away to form a large-end hole and a small-end hole.

Method of manufacturing connecting rod

A metallic product is formed by an electric upsetter having anvil and clamp electrodes. The anvil electrode is made of a material having a relatively small thermal conductivity. A rod-shaped blank of a metallic material is placed between the anvil and clamp electrodes. Then, an electric current is passed through the rod-shaped blank to heat the same. The rod-shaped blank is pushed toward the anvil electrode under a constant force to thicken an end of the rod-shaped blank which is held against the anvil electrode. The electric current passed through the rod-shaped blank is controlled such that the rod-shaped blank is pushed at a predetermined speed depending on a displacement by which the rod-shaped blank is pushed toward the anvil electrode, thereby producing a preliminary product with the thickened end. The preliminary product is subsequently formed into an engine valve by closed-die forging.

Method of forming metallic product

Growing community of inventors

Tochigi-ken, Japan

Ryuji Soga