Patent ID: 11969774
Assignee: MITSUBISHI ELECTRIC CORPORATION
Field: Machine tools (Mechanical engineering)
Classification: CPC B  F  Y | IPC B  F

Claim 0:
1. A method of manufacturing a check valve, comprising:
placing a raw tube made of copper such that the raw tube is held in a die;
pushing axial push tools from respective opposite ends of the raw tube, and fixing the raw tube;
filling an inside of the raw tube with fluid;
forming a valve seat at an inner circumferential surface of the raw tube by further pushing the axial push tools from the respective ends of the raw tube, such that between the axial push tools, the valve seat has a greater thickness than part of the raw tube that is other than the valve seat;
inserting a valve body into the raw tube; and
forming an inlet portion and an outlet portion at respective opposite end portions of the raw tube by tube-reducing processing,
wherein in the forming the valve seat, the raw tube is formed having a nonuniform thickness such that part of the raw tube is gathered inwardly and the raw tube is not deformed outwardly.