ELECTRIC LINEAR MOTION ACTUATOR AND ELECTRIC DISC BRAKE DEVICE

摘要

An electric linear motion actuator is provided of which the planetary rollers can be kept in elastic contact with the radially outer surface of the rotary shaft at all times using inexpensive elastic rings such that the rotation of the rotary shaft is reliably transmitted to the planetary rollers at all times. The planetary rollers (21) are mounted between the radially inner surface of an outer ring member (5) and the radially outer surface of a rotary shaft (10). The actuator further includes a carrier (14) rotatable about the rotary shaft (10) and including as many roller shafts (19) as the planetary rollers (21) which are radially movable and rotatably support the respective planetary rollers (21). Elastic rings (23) each having circumferentially separate ends are each wrapped around the roller shafts (19) to radially inwardly bias the roller shafts (19), thereby bringing the respective planetary rollers (21) into elastic contact with the radially outer surface of the rotary shaft (10). Each elastic ring (23) is prevented from rotating relative to the roller shafts (19), thereby preventing one of the roller shafts (19) from being axially aligned with the gap between the circumferential separate ends, causing the elastic ring (23) to be radially compressed and thus making it impossible for the elastic rings (23) to radially bias the roller shafts (19).