Identification and quality requirements of clutch pressure plate spring

The function of the pressure plate spring is to use its tension to tightly press the clutch pressure plate and the clutch plate on the minute wheel, so that the power of the engine can be reliably transmitted to the drive train.

The quality requirements of the pressure plate spring are as follows:

1) Material: The material of the pressure plate spring is 65Mn steel wire or group I and II carbon spring steel wire.

2) Hardness: The hardness value of the cold coiled spring after quenching and tempering treatment should be in the range of 44-52HRC. Under special circumstances, the hardness value can be expanded to 55HRC.

3) Appearance quality requirements: The surface quality of the finished spring should be smooth, free of defects such as cracks, oxide skin, and corrosion. Cold rolled springs are not allowed to have individual indentations, pits and scratches whose depth exceeds half of the material diameter tolerance.

4) Processing density

a. The surface roughness of the spring should not be less than 12.5µm.

b. The flattened part of the compression spring support ring with both ends of the ring 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.

c. 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 coils of normal pitch are not allowed to contact.

d. 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.

e. The straightness tolerance of the compression spring axis line is half of the perpendicularity tolerance.