Method of forming fracture start portion of con rod and forming device
AssigneeYasunaga Corporation
InventorsYuji KAIMASU, Jungo MATSUI
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Abstract
A method of forming a fracture start portion of a con rod for forming fracture start portions of a con rod at opposing positions in an inner peripheral surface of a large end of the con rod made of metal, includes a first step of forming a groove portion at a position corresponding to the fracture start portion by using a first insert tip with a large tip end and a second step of forming the fracture start portion, which has become a V-shaped groove, by machining a bottom portion of the groove portion smaller by using a second insert tip having a tip end smaller than the first insert tip.
Claims3
A method of forming a fracture start portion of a con rod for forming fracture start portions of a con rod at opposing positions in an inner peripheral surface of a large end of the con rod made of metal, comprising:
- a first step of forming a groove portion at a position corresponding to the fracture start portion by using a first insert tip with a large tip end R;
- and
- a second step of forming a V-shaped groove by machining a bottom portion R of the groove portion smaller using a second insert tip having a tip end R smaller than the first insert tip.
A fracture start portion forming device of a con rod for forming fracture start portions of a con rod at opposing positions in an inner peripheral surface of a large end of the con rod made of metal, wherein
- after a groove portion is formed at a position corresponding to the fracture start portion by using a first insert tip having a large tip end R, the fracture start portion of the con rod is formed which has become a V-shaped groove by machining a bottom portion R of the groove portion smaller by using a second insert tip having a tip end R smaller than the first insert tip.
Dependencies are inferred from the claim text.