COIL SPRING AND ITS ATTACHING METHOD

PROBLEM TO BE SOLVED: To prevent occurrence of a crack to the next stage coil, and provide a coil spring hardly deteriorated, by forming in the end coil of the coil spring, a damage preventing part to avoid stress concentration against the next stage coil brought into contact with the end coil. SOLUTION: A taper slit part 10A1 is arranged in a first stage coil part 10A so as to be brought into tight contact with a contact surface. Hereby, a coil spring 10 can be perpendicularly erected against the contact surface. When the coil spring 10 is pushed up from the contact surface, the coil spring 10 is compressed, and the coil side projected end part 10A2 of the first stage coil part 10A and the contact surface side projected end part 10B1 of a second stage coil part 10B are brought into contact with each other. At this time, a curved surface part (damage preventing part) 10A3 is arranged, which is formed at the end of the coil side projected end part 10A2, therefore the end of the coil side projected end part 10A2 can be prevented from being brought into contact with the contact surface side projected end part 10B1.