Abstract: A spiral spring for reducing maximum stress value and variations in stress distribution. The spiral spring is elastically deformable from a minimally to maximally deformed state. In maximally deformed state, the spiral spring includes a non-contact section, wherein at least some spring material portions are adjacent in radial direction not contacting each other, and a contact section, wherein all spring material portions are adjacent in radial direction contacting each other. An inner reference portion is corresponding to a central angle of 80° or more and 160° or less about a spiral center along a direction of spiral portion extension with a reference line connecting the spiral center and outer contact portion, wherein the outer end portion and outer fixing member contact in maximally deformed state, the inner reference portion being on a radially spiral portion inner side. The contact section is on a radially inner reference portion outer side.

Abstract: The present invention is directed to a helical compression spring which is mounted on a vehicle body to be compressed between an upper seat and a lower seat. The spring has a coil axis that is substantially curved at a predetermined radius of curvature in an unloaded state of the spring. A pitch of a lower end coil of the spring is set to tilt the end plane of the lower end coil at a first predetermined angle to the lower seat in the direction for shortening the longitudinal length of the spring at the inside of the curvature, and/or a pitch of an upper end coil is set to tilt the end plane of the upper end coil at a second predetermined angle to the upper seat in the direction for shortening the longitudinal length of the spring at the outside of the curvature. The coil axis of the spring may be substantially curved in accordance with at least two radius of curvature in the unloaded state of the spring.