The utility model provides a for adjustment after the car axle main reducer is active bevel gear bearing pre tightening force across the set and its characteristics is the spacer sleeve for a thick wall cone shaped single section corrugated sleeve, use it to replace the ordinary tubular spacer sleeve and adjusting shim, achieve the stepless adjustment, flexible control, adjust the bearing pre tightening quickly, simple and reliable, bearing preload meet 4 ~ 6 kg.