PURPOSE: To intend to simplify manufacture of a spring assembly, by providing an inserting port with opened one part of a fitting groove formed with a bent ring-shaped base plate, herefrom inserting a coil seat part formed in one end of a coil spring so as to be same dimension as the fitting pitch interval, and hereafter closing the other end of the fitting groove.

CONSTITUTION: A ring-shaped base plate 1 consists of a bottom plate part 3 and inner and outer side parts 4, 5 which are bent at inner and outer ring end of the base plate in U-shape and formed into a fitting groove 6. Moreover a oil spring 2 consists of an acting part 7 of a small diameter and a coil seat part 8 of a large diameter, and the coil seat part 8 is inserted in the fitting groove 6. Besides the coil seat part 8 is wound in the same dimension as the fitting pitch interval. In this manufacture firstly either one of inner and outer sides plates 4, 5 is kept in no bending state so as to form the inserting port in the ring-shaped base plate 1 and herefrom the coil seat part 8 of the coil spring is inserted and hereafter the remaining side plate is bent. Therefore it can be manufactured easily.