ELECTRIC LINEAR ACTUATOR

An object of the present invention is to provide an electric linear actuator provided with the anti-rotation mechanism for the screw shaft which is able to achieve a simple structure and thus low manufacturing cost and to reduce the sliding friction and wear. 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; 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; and a blind bore formed on the housing for containing an end of the screw shaft characterized in that a sleeve for an anti-rotation of the screw shaft is fitted in the blind bore of the housing and is press-formed of steel sheet.