Electric linear actuator

摘要

An electric linear actuator has a housing with an electric motor, a speed reduction mechanism and a ball screw mechanism. The ball screw mechanism converts the rotational motion of the electric motor to an axial linear motion of a drive shaft. The ball screw mechanism has a nut and a screw shaft. The screw shaft is inserted into the nut, via a large number of balls. The screw shaft is axially movably supported on the housing but is non-rotatable with respect to the housing. An output gear, forming part of the speed reduction mechanism, is secured on the nut. The bearings are arranged at either side of the output gear. The bearings are mounted on the housing, via a ring-shaped washer, formed from an elastic member.

主权项

1. An electric linear actuator comprising:
a housing; an electric motor mounted on the housing; a speed reduction mechanism for transmitting the rotational power of the electric motor to a ball screw mechanism via a motor shaft while reducing a motor speed; the ball screw mechanism converts the rotational motion of the electric motor, transmitted via the speed reduction mechanism, to an axial linear motion of a drive shaft, the ball screw mechanism includes a nut and a screw shaft, the nut is formed with a helical screw groove on its inner circumference, the nut is rotationally supported by bearings on the housing, the bearings include an an outer rim and an inner ring, the nut is axially immovable with respect to the housing, the screw shaft is coaxially integrated with the drive shaft, the screw shaft is formed with a helical screw groove on its outer circumference that corresponds to the helical screw groove of the nut, the screw shaft is inserted into the nut, via a large number of balls, the screw shaft is axially movably supported on the housing, the screw shaft is non-rotatable with respect to the housing; an output gear secured on the nut forms part of the speed reduction mechanism; and the bearings are arranged at either side of the output gear and are mounted on the housing, one of the bearings is arranged on the axially output side of the output gear, and is mounted on the housing via a washer; the washer is a ring-shaped washer formed from an elastic member and is separate from the outer ring, the ring-shaped washer is positioned between at least one of the bearings and a housing wall to prevent contact of the inner ring of the bearing with the housing wall.