In important occasions, the YI type should be used to ensure that the two supporting end faces are perpendicular to the axis of the spring, so that the spring will not skew when it is compressed. When the spring wire diameter d≤0.5mm, the two supporting end faces of the spring do not need to be ground. For springs with d>0.5mm, both supporting end faces need to be ground flat. The flat part should be no less than 3/4 of the circumference. The end thickness is generally not less than d/8, and the end surface roughness should be less than
1. The distance between each coil of the spring
Let the pitch of the spring be p; the diameter of the spring wire is d; in the free state, there should be an appropriate spacing δ between the turns. In order to maintain a certain elasticity of the spring after compression, it is also necessary to ensure that there is still a certain distance δ1 between the rings under the maximum load. The size of δ1 is generally recommended as: δ1=0.1d≥0.2mm
2. Dead circle
The two end face rings of the spring are tight with the adjacent ring (no gap), and only play a supporting role without participating in deformation, so it is called a dead ring. When the number of working turns of the spring n≤7, the dead loop at each end of the spring is about 0.75 turns; when n>7, the dead loop at each end is about 1 to 1.75 turns.
3. End structure
YI type: Both end face rings are tight with the adjacent ring, and they are ground on a special grinder;
YII type: When heating and winding, the two ends of the spring wire are forged flat and tight with the adjacent ring (the end ring can be ground or not);
YIII type: Both end face rings are not flat with the adjacent ring.