| 摘要 |
A manufacturing method of a master-cylinder primary piston for a vehicle is provided to reduce processing cost, improve productivity, and mass-produce products with good quality by cold forging an aluminum alloy, thereby manufacturing the primary piston. A manufacturing method of a master-cylinder primary piston(1) for a vehicle comprises: a cutting process(100) of cutting an aluminum round bar with a predetermined thickness into short rods(A) with the same weight; a hardening process(200) of positioning a hardening pin(202) and a supporting bar(203) at upper and lower sides of the short bar respectively in a state that the short bar is inserted into a hardening tool(201), and pressurizing the hardening pin by a pressurizing unit; a spring inserted pipe-forming process(400) of positioning a pressurizing pin(402) and a spring inserted pipe-forming pin(403) at upper and lower sides of the short bar respectively in a state that the short bar is inserted into a spring inserted pipe-forming tool(401), and pressurizing the pressurizing pin by a pressurizing unit to form a spring inserted pipe(3); and a guiding groove-forming process(500) of positioning a forming pin(502) and a supporting pin(503) at upper and lower sides of the formed object respectively in a state that a formed object(B) is inserted into a guide groove-forming tool(501) in a way that the spring inserted pipe faces upward, and pressurizing the forming pin by a pressurizing unit to form guiding grooves(4) and a spring locking projection(5). |
