Method of manufacturing spring assembly

A method of manufacturing a spring assembly, which includes annular plates and compression coil springs, and which is adapted to assemble the compression coil springs to each of the annular plates by caulking projection portions formed in the annular plates, the method comprising:

• forming the projection portions in each of the annular plates, the projection portions to be opposite each other;
• setting one of end turn portions of each of the compression springs on the projection portions of one of the annular plates, wherein plural large-diameter walls and plural small-diameter walls are alternately provided in a circumferential direction of each of the projection portions;
• inserting a punch having a portion, whose diameter is larger than an inside diameter of a space between the small-diameter walls, inside a space surrounded by the large-diameter walls and the small-diameter walls of the projection portions, the punch forcibly and outwardly spreading the small-diameter walls, thereby enlarging the large-diameter walls adjoining each of the small-diameter walls and the projection portions in diameter;
• setting the other end turn portion of each of the compression coil springs on an associated one of the projection portions of the other annular plate;
• and
• inserting a punch having a portion, whose diameter is larger than an inside diameter of a space between the small-diameter wall, inside a space surrounded by the large-diameter walls and the small-diameter walls of each of the projection portions provided in the other annular plate, the punch forcibly and outwardly spreading the small-diameter walls, thereby enlarging the large-diameter walls adjoining each of the small-diameter walls and the projection portions in diameter.

A method of manufacturing a spring assembly, which includes two annular plates and compression coil springs, and which is adapted to assemble the compression coil springs to the annular plates by caulking projection portions formed in the two annular plates, the method comprising:

• forming the projection portions in each of the annular plates, the projection portions being opposite each other;
• alternately providing plural large-diameter walls and plural small-diameter walls in a circumferential direction of the projection portions;
• and
• inserting a punch having a portion, whose diameter is larger than an inside diameter of a space between the small-diameter walls, inside a space surrounded by the large-diameter walls and the small-diameter walls of each of the projection portions provided in the one of the annular plates, the punch forcibly and outwardly spreading the small-diameter walls, thereby enlarging the large-diameter walls adjoining each of the small-diameter walls and the projection portions in diameter.