Patent ID: 9182021
Filing Date: 2015-11-10
Classification: B60T,F16D,F16H,Y10T

Abstract:
1. An electric linear motion actuator comprising an electric motor having a rotor shaft, a reduction gear mechanism including an output gear having a center axis for reducing a rotation of the rotor shaft of the electric motor and outputting the thus reduced rotation at the output gear, a slide member movable in a direction of the center axis of the output gear, a rotation-to-linear-motion converting mechanism for converting a rotary motion of the output gear of the reduction gear mechanism to a linear motion and transmitting the linear motion to the slide member, and a locking mechanism capable of selectively rotationally locking and unlocking the rotor shaft of the electric motor, wherein the locking mechanism comprises a plurality of engaging portions provided on one side of one of a plurality of gears forming the reduction gear mechanism so as to be arranged in a circumferential direction of the one of the plurality of gears, a locking pin movable toward and away from the engaging portions and configured to be brought into engagement with any one of the engaging portions when moved toward the engaging portions, thereby locking the gears of the reduction gear mechanism, and a pin driving actuator for driving the locking pin between an advanced position and a retracted position, the pin driving actuator being mounted between the electric motor and a housing in which the slide member and the rotation-to-linear-motion converting mechanism are mounted, wherein the engaging portions are each formed with a locking surface provided at one circumferential end of the engaging portion and configured such that when the locking pin engages the locking surface, the locking surface prevents the one of the plurality of gears from rotating in a direction in which the slide member moves backward, and a tapered surface provided at another circumferential end of the engaging portion and configured such that when the one of the plurality of gears tends to rotate in a direction in which the slide member is advanced, the locking pin is allowed to separate from the engaging portion while sliding along the tapered surface.