Patent ID: 8487492
Filing Date: 2013-07-16
Classification: F16H

Abstract:
1. A motor assembly, comprising a gearbox and a motor engaging the gearbox, a motor shaft of the motor being supported by a first bearing fixed in a front cap of the motor, one end of the motor shaft protruding from the front cap and being supported by a second bearing fixed in the gearbox, a worm fixed to a worm portion of the motor shaft between the first and second bearings, the worm rotating with the motor shaft to drive a worm gear of the gearbox, wherein the gearbox comprises a chamber located between the first bearing and the worm, a bushing assembly being fixed in the chamber, the bushing assembly comprising a sleeve and a bushing disposed inside the sleeve, the motor shaft being supported by the bushing, the bushing having a plurality of ribs arranged around its outer peripheral surface, the sleeve engaging with an inner surface of the chamber and having a plurality of grooves in an inner surface engaging the ribs on the bushing, axial ends of the bushing assembly being contacted by the front cap and the bottom of the chamber preventing the bushing assembly from moving axially, a stopper being formed at one end of the sleeve, the sleeve comprising a plurality of ridges each of which is formed between two adjacent grooves, a bump extending radially inwardly being formed on at least some of the ridges, at the end of the sleeve remote from the stopper, the bumps cooperating with the stopper to prevent the bushing moving axially with respect to the sleeve, the sleeve having a plurality of axial ribs formed on an outer peripheral surface, the chamber having a plurality of axial grooves engaging the axial ribs of the sleeve, one end of each axial rib tapering axially to form a guide portion, one end of each axial groove tapering axially to form a guide portion, the guide portions of the chamber and the guide portions of the sleeve matching mutually with each other to guide the engagement of the sleeve with the chamber.