摘要 |
PROBLEM TO BE SOLVED: To reduce machining time, to improve dimensional precision and to stabilize quality by using a carbon steel for JIS machine structures in the range of S35C-S55C, machining simultaneously the outline, cam groove and hole through fine blanking after spheroidizing annealing, applying a heat treatment to the entire plate after the machining, and imparting a required hardness to form a product. SOLUTION: The manufacturing is by four processes in figure (b) : (STO1) preparation of a base material; (STO2) the base material is spheroidized, given a Rockwell hardness of 28-32, and improved in cold blanking characteristics; (STO3) the outer circumference 31, attaching hole 32, 33 and cam groove 34 of a cam plate 30 are blanked simultaneously by fine blanking, also with a press oil used as a lubricant containing at least 10% or more of molybdenum disulfide, improving the roughness on the broken-out section in blanking; and (STO4) the blanked cam plate 30 is quenched, tempered and hardened to have a Rockwell hardness 52-58. |