Patent ID: 7357381
Filing Date: 2008-04-15
Classification: B21F,B21K,B23P,F16D,F16F,Y10T

Abstract:
1. A method of manufacturing a spring assembly, which includes two annular plates and compression coil springs, said compression coil springs being assembled to said annular plates by caulking projection portions formed on said two annular plates, respectively, the method comprising: forming both of large-diameter projection portions and small-diameter projection portions in each of said two annular plates, while forming large-diameter end turn portions, which are respectively associated with said large-diameter projection portions, and small-diameter end turn portions, which are respectively associated with said small-diameter projection portions, in said compression coil springs; setting the large-diameter end turn portions on outer peripheries of the large-diameter projection portions; inserting a first punch having a portion, whose diameter is larger then an inside diameter of said large-diameter projection portions, thereinto and enlarging said large-diameter projection portions in diameter thereof to the thereby assemble said large-diameter end turn portions of said compression coil springs to said annular plates; subsequently setting said small-diameter end turn portions on outer peripheries of said small-diameter projection portions; and inserting a second punch having a portion, whose diameter is larger than an inside diameter of said small-diameter end turn portions, from inside diameter of said large-diameter projection portions thereinto and enlarging said small-diameter projection portions in diameter thereof to thereby assemble said small-diameter end turn portions of said compression coil springs to said annular plates, wherein the large-diameter projection portions are arranged opposed to the small-diameter projection portions, and wherein the outer periphery of the large-diameter projection portions is larger than the outer periphery of the small-diameter projection portions.