ELECTRIC LINEAR ACTUATOR AND ELECTRIC DISC BRAKE DEVICE

摘要

An outer ring member (5) movable in a shaft direction is assembled in a housing (1), and a rotating shaft (10) rotationally driven by an electric motor (11) is provided above the shaft center of the outer ring member (5). A planetary roller (21) is rotatably supported by a carrier (14) rotatably supported centered on the rotating shaft (10). A spiral groove (23) to be engaged to the spiral projection (6) provided on the inner diameter surface of the outer ring member (5) is formed on the outer diameter surface of the planetary roller (21). The rotation of the rotating shaft (10) makes the planetary roller (21) rotate and revolve by the frictional contact with the rotating shaft (10) and makes the outer ring member (5) move linearly in the shaft direction. The shaft direction force in the push-in direction, which is loaded to the planetary roller (21) from the outer ring member (5), is received by a thrust bearing (24) assembled between the planetary roller (21) and an inner-side disc (14a) of the carrier (14). An aligning seat (27) is provided between the planetary roller (21) and the thrust bearing (24) and shear movement is made to occur at the contact surface of the aligning seat (27) by an unbalanced load loaded to the planetary roller (21) from the outer ring member (5), thereby equalizing the surface pressure distribution in a circumferential direction of the thrust bearing (24).