Patent ID: 8025039

Claim:
A valve spring device which urges a valve attached to a port in a closing direction, the valve spring device comprising: a first spring formed of a compression coil spring and deformable in an axial direction of the valve, wherein the first spring has a wire including portions which contact one another when an axial load acting in a direction to compress the first spring exceeds a predetermined value; and a second spring disposed in series with the first spring and held by a stopper in a manner such that the second spring is subjected to a preload by axial compression, wherein the preload of the second spring is larger than an installation load of the first spring, and wherein the valve spring device has load-deflection characteristics such that only the first spring deforms axially when the axial load acting in the direction to compress the first spring is not larger than the predetermined value, and such that both the first and second springs deform axially when the axial load exceeds the predetermined value.