Patent ID: 8656798

Claim:
A linear actuator comprising: a rotational motion component; a linear motion component; and a ball screw mechanism configured to convert a rotational motion transmitted to the rotational motion component into a linear motion, wherein the ball screw mechanism has a guide projection projecting in a radial direction and provided in the linear motion component, and a guide groove engaged with the guide projection and disposed in a securing portion facing the linear motion component to guide the guide projection in an axial direction, and has a structure to make the linear motion component subject not to rotate, the rotation of the guide projection is restricted at a shaft arranged in the linear motion component and a first position of the guide projection is adjustable in an axial direction, and is provided on a first outer peripheral surface of a cylindrical body with a shaft end position at the stroke end secured in such a manner that the axial end portion can be shifted along the axial direction, and the guide projection has a projection projecting by a predetermined length from the guide groove, while engaging into the guide groove, at a stroke end of the linear motion component, and abuts a abutting portion provided in the rotational motion component with the projection of the guide projection, the guide groove is formed in a guide member having a second outer peripheral surface in the axial direction, and the guide member is fit into a support hole in a rotatable manner, the support hole being formed in the axial direction at a second position, facing the linear motion component, of the securing portion, the second outer peripheral surface has a cylindrical portion, the support hole has an inner circumference surface, and the guide member has an engage groove on the cylindrical portion, the engage groove being engaged with a projecting stripe formed on the inner peripheral surface, the projecting stripe extending along a circumferential direction of the inner circumference surface.