Electrically driven linear actuator

摘要

Electrically driven linear actuator which can suppress generation of vibration or noise even if the alternating load or vibratory load would be applied to the actuator. Electrically driven linear actuator comprising an electric motor (5) mounted on a housing; a screw shaft (7) coaxially connected to a motor shaft (5a) of the electric motor (5) and formed on its outer circumferential surface with a screw groove (7a); a nut (8) threadably engaged with the screw shaft (7), having a pair of supporting shafts (12) on the outer circumferential surface of the nut (8) supporting one end of a link (2) and formed on its inner circumferential surface with a screw groove (8a) corresponding to the screw groove (7a) of the screw shaft (7); a number of balls (9) contained between the screw grooves (7a,8a); ball circulating members (14) each being formed with an endless ball circulating passage (15) between the screw grooves (7a,8a); a ball screw (3) for converting a rotary motion of the electric motor (5) to an axial motion of the nut (8) and causing a swing motion of the link (2) via the supporting shafts (12); and a pair of supporting bearings (10,11;22,11) for supporting the screw shaft (7) rotatably but axially immovably relative to the housing (4), one supporting bearing (10,22) arranged at a side of the electric motor (5) of each pair of the supporting bearing is an angular ball bearing and the other supporting bearing (11) is a sliding bearing.