A. The flattened part of the compression spring support ring with both ends and tightly ground is not less than 3/4 of the circumference, and the end thickness is generally not less than 1/8 of the diameter of the wire. For springs with flat forged ends, the end thickness should be no more than 1/3 of the wire diameter, and the width should be no less than 70% of the wire diameter.
B. According to the application requirements, the unevenness of the spring pitch can be checked. The tolerance is 10% of the pitch, and the minimum tolerance value is generally 0.3mm. When the compression spring is compressed to 80% of the full deformation, the spring coil of normal pitch is not allowed to contact.
C. The perpendicularity tolerance between the two ends of the compression spring and the spring axis is 2.5% of the free height, and the minimum tolerance is 1mm.
D. The straightness tolerance of the compression spring axis is half of the perpendicularity tolerance
E. The surface roughness of the spring should not be less than 12.5?m.