Abstract:

After a certain type of relay is stored in a low-temperature environment of -55 ℃, there exists a problem that the release voltage decreases significantly or even fails. Through problem investigation, a thermal-structural coupling simulation model is used to quantitatively analyze the deformation of the shaft-hole of the relay at low temperature. It is found that the deformation of the hole at low temperature is about 3 times that of the shaft, and the burrs exist in the holes of the failed products. The analysis shows that the deformation of parts will increase the shaft-hole pressure, leading to a simultaneous increase in friction, which ultimately reduces the product release voltage. By optimizing the minimum shaft-hole fit clearance of 3 batches of products from 0.01 mm to 0.02 mm and strengthening the control of burrs in the holes, the product qualification rate increased from 85% to over 98% verifying the effectiveness of the optimization scheme, which provides a new design direction for relay tolerance optimization and burr control in the shaft-hole design of drive components.

Key words: relay, low-temperature environments, release voltage degradation, tolerance optimization