Electric linear motion actuator and electric brake system

摘要

An electric brake system is proposed which includes an electric linear motion actuator and can generate the required braking force with high accuracy. A load sensor (30) is provided in a motion converting mechanism of the actuator which converts the rotary motion of a rotary shaft (4) to which the rotation of an electric motor (2) is transmitted to linear motion of an outer ring member (5) as an output member. The load sensor (30) detects the pushing force with which the outer ring member (5) linearly drives a driven member. With this arrangement, if the driven member is a braking member of an electric brake system, it is possible to directly detect the braking force applied by the driven member and thus to accurately generate the required braking force.

主权项

1. An electric linear motion actuator comprising:
a housing; a rotary member rotatably mounted to the housing; an electric motor having a rotor shaft operably connected to the rotary member to transmit rotary motion of the rotor shaft to cause rotary motion of the rotary member; a motion converter mechanism provided in the housing for converting rotary motion of the rotor shaft of the electric motor, or rotary motion of the rotary member, to a linear motion of an output member for linearly driving a driven member in forward and rearward directions, wherein the driven member is configured to be pushed by a front side of the output member; a thrust bearing which receives a rearward reaction force of a pushing force of the output member; a backup member mounted in the housing and axially supporting the thrust bearing, the backup member including an annular portion and an axially elongated cylindrical portion extending from the annular portion, said annular portion and said cylindrical portion together having a single common radially inner surface; a plurality of bearings including first and second bearings mounted within said single common radially inner surface, such that the first and second bearings are axially spaced apart from each other and such that the first and second bearings are supported by the backup member; a stopper fixed to the housing and restricting axial movement of the backup member in a rearward direction; a load sensor mounted between the thrust bearing and the backup member, or between the backup member and the stopper; and a heat insulator protecting the load sensor; wherein the load sensor is configured to detect a pushing force with which the output member pushes the driven member when the driven member is linearly driven by the output member; and wherein the rotary member is rotatably supported by the backup member via the plurality of bearings.