ELECTRIC LINEAR ACTUATOR

An object of the present invention is to provide an electric linear actuator which can reduce damage and wear of the housing and perform the anti-rotation of the nut with a simple structure to improve the reliability and manufacturing cost of the electric linear actuator. According to the present invention, there is provided an electric linear actuator comprising a housing; an electric motor mounted on the housing; a speed reduction mechanism for reducing rotational speed of the electric motor via a motor shaft; and a ball screw mechanism for converting rotational motion of the electric motor transmitted via the speed reduction mechanism to axial linear motion of a driving shaft; the ball screw mechanism comprising a nut formed with a helical screw groove on its inner circumference and supported by bearings mounted on the housing rotationally but axially immovably, and a screw shaft coaxially integrated with the driving shaft, formed with helical screw groove on its outer circumference corresponding to the helical screw groove of the nut, inserted into the nut via a large number of balls, and supported on the housing axially movably but not rotationally, characterized in that a sleeve is secured on the housing for preventing rotation of the screw shaft relative to the housing and formed with at least one axially extending recessed groove on the inner circumference of the sleeve; that at least one guide pin mounted on the end of the screw shaft is engaged with the recessed groove; and that a tapering chamfered portion is formed on the end of the nut.