Vacuum booster assembly

The invention relates to the technical field of vacuum boosters, and discloses a vacuum booster assembly. The vacuum booster assembly comprises a vacuum booster and a brake master cylinder, wherein the vacuum booster comprises a control piston; the brake master cylinder comprises a master cylinder body and an input a rod; one end of the input rod extends into the control piston along the master cylinder body; a large spring connecting the input rod and the control piston sleeves the input rod; a sleeve sleeves the input rod; the sleeve is in threaded connection to the input rod; one end of thelarge spring abuts against one end portion of the sleeve, and the other end of the large spring abuts against an end surface of the control piston; and the pretightening force of the large spring canbe adjusted by adjusting the position, of the sleeve, relative to the input rod. The vacuum booster assembly can adjust the performance parameters of the vacuum booster assembly so as to meet different performance requirement