ELECTRIC LINEAR MOTION ACTUATOR AND ELECTRIC DISK BRAKE SYSTEM

摘要

An electric linear motion actuator includes planetary rollers mounted between the radially inner surface of an outer ring member and the radially outer surface of a rotary shaft, and a carrier rotatable about the rotary shaft and including radially movable roller shafts rotatably supporting the respective planetary rollers. Elastic rings each having circumferentially separate ends are each wrapped around the roller shafts to radially inwardly bias the roller shafts, thereby bringing the respective planetary rollers into elastic contact with the radially outer surface of the rotary shaft. Each elastic ring is prevented from rotating relative to the roller shafts, thereby preventing one of the roller shafts from being axially aligned with the gap between the circumferential separate ends, causing the elastic ring to be radially compressed and thus making it impossible for the elastic rings to radially bias the roller shafts.

主权项

1. An electric linear motion actuator comprising:
a housing; an outer ring member mounted in the housing and having a center axis; a rotary shaft extending along the center axis of the outer ring member, and configured to be rotationally driven by an electric motor; a carrier supported on the rotary shaft so as to be rotatable about the rotary shaft; and planetary rollers mounted between a radially outer surface of the rotary shaft and a radially inner surface of the outer ring member, and rotatably supported by the carrier, wherein the outer ring member has a helical rib formed on the radially inner surface of the outer ring member and in engagement with circumferential grooves formed on a radially outer surface of each of the planetary rollers, whereby when the rotary shaft rotates, the planetary rollers are configured to rotate due to frictional contact between the rotary shaft and the respective planetary rollers, thereby moving the outer ring member in an axial direction, wherein the electric linear motion actuator further comprises a friction coupling arrangement configured to frictionally fixedly couple the carrier to the rotary shaft while an axial load applied to the outer ring member in a push-in direction is small, and to uncouple the carrier from the rotary shaft under the axial load when the axial load is large.