Electric Linear Actuator

The electric linear actuator comprising:

• a housing formed of aluminum alloy;
• an electric motor mounted on the housing;
• a speed reduction mechanism reducing rotational speed of the electric motor via a motor shaft;
• a ball screw mechanism for converting rotational motion of the electric motor, transmitted via the speed reduction mechanism, to axial linear motion of a drive shaft, the ball screw mechanism comprising a nut and a screw shaft, the nut includes a helical screw groove on its inner circumference, the nut is rotationally supported by bearings mounted on the housing but is axially immovable with respect to the housing, the screw shaft is coaxially integrated with the drive shaft, the screw shaft including a helical screw groove on its outer circumference corresponding to the helical screw groove of the nut, the screw shaft inserts into the nut via a large number of balls, the screw shaft is axially movably supported on the housing but is not rotatable with respect to the housing;
• an anti-rotation mechanism for preventing rotation of the screw shaft relative to the housing, the anti-rotation mechanism including a sleeve and a guide pin, the sleeve fit into the blind bore of the housing, the guide pin mounts on the end of the screw shaft via a through-aperture in the screw shaft, the guide pin engages linear recessed grooves of the sleeve;
• and
• the sleeve is fit into a blind bore of the housing so that projecting portions, each having a semicircular cross-section, formed on an outer circumference of the sleeve engage recessed grooves, each having a circular-arc cross-section, on an inner circumference of the blind bore of the housing to prevent rotation of the sleeve relative to the housing.