According to the embodiments of the present invention, the overall size reduction allows installation space to be advantageously secured, reduction in noise generated during operation improves the comfort of the driver, and the strength and stability of the connective structure between parts can be increased and power transmission can be more effective.

A planetary roller screw drive for an actuator of a rear-axle steering system of a motor vehicle, including a planetary roller support which accommodates the planetary rollers and is connected to a drive sleeve for rotation therewith, which drive sleeve is driven rotatably about the screw spindle and is mounted rotatably on a machine part by an axial angular contact roller bearing which is arranged coaxially with respect to the drive sleeve and of which the rollers are in rolling contact with angled-bearing raceways which are inclined with respect to a plane arranged transversely with respect to the axis of rotation of the drive sleeve.

A spindle drive (20) for an actuator of a steer-by-wire steering system (10). The spindle drive has a linearly displaceable threaded spindle (27). The spindle drive (20) is in the form of a roller screw drive. The roller screw drive has a first efficiency in the driving direction and a second different efficiency in the reverse-driving direction.

A reverse input blocking clutch includes an input member, an output member, a pressed member, and an engaging member. When a rotational torque is inputted to the input member, the engaging member moves in a direction away from a pressed surface of the pressed member due to engagement with the input member, and transmits the rotational torque inputted to the input member to the output member due to engagement with the output member; and when rotational torque is reversely inputted to the output member, moves in the direction closer to the pressed surface based on engagement with the output member, and by being pressed against the pressed surface does not transmit the rotational torque reversely inputted to the output member to the input member, or transmits only part thereof to the input member due to engagement with the input member.

A linear actuator system having an actuator housing, a motor assembly, a screw shaft, a thrust tube, and a nut assembly. The nut assembly is engaged with the screw shaft and directly coupled with the thrust tube. The nut assembly can define a mechanical fitting for direct physical engagement between the thrust tube and the nut assembly, absent additional load bearing components intervening therebetween. The nut assembly is configured to convert rotational motion of the rotor about the longitudinal axis to linear motion of the thrust tube along the longitudinal axis. A cooling loop can be at least partially embedded, potted or seated within the actuator housing, with a thermally conductive material disposed at least partially about the cooling loop to conduct heat from the actuator housing.

A linear actuator system having an actuator housing, a motor assembly, a screw shaft, a thrust tube, and a nut assembly. The nut assembly is engaged with the screw shaft and directly coupled with the thrust tube. The nut assembly can define a mechanical fitting for direct physical engagement between the thrust tube and the nut assembly, absent additional load bearing components intervening therebetween. The nut assembly is configured to convert rotational motion of the rotor about the longitudinal axis to linear motion of the thrust tube along the longitudinal axis. A cooling loop can be at least partially embedded, potted or seated within the actuator housing, with a thermally conductive material disposed at least partially about the cooling loop to conduct heat from the actuator housing.

A load sensor to be used in an electromechanical brake system includes a flange member capable of deflecting when receiving, at a load receiving portion, a load from the axially front side; a support member capable of supporting the flange member from the axially rear side, at a support portion displaced from the load receiving portion in a radial direction orthogonal to the axial direction; and a displacement detecting mechanism configured to detect the amount of relative movement between the flange and support members. A variable detection sensitivity mechanism enables the relative movement amount with respect to the change of the load applied to the flange member to be larger in a low load range in which the load is equal to or lower than a predetermined load value than in a high load range in which the load is higher than the predetermined load value.

Provided is a reverse input blocking clutch capable of easily releasing a state in which rotation of an output member is prevented or suppressed.

The reverse input blocking clutch 5 includes an input member 14, an output member 15, a pressed member 16, and an engaging member 17. When a rotational torque is inputted to the input member 14, the engaging member 17 moves in a direction away from a pressed surface 28 of the pressed member 16 due to engagement with the input member 14, and transmits the rotational torque inputted to the input member 14 to the output member 15 due to engagement with the output member 15; and when rotational torque is reversely inputted to the output member 15, moves in the direction closer to the pressed surface 28 based on engagement with the output member 15, and by being pressed against the pressed surface 28 does not transmit the rotational torque reversely inputted to the output member 15 to the input member 14, or transmits only part thereof to the input member 14 due to engagement with the input member 14.

A spindle drive (20) for an actuator of a steer-by-wire steering system (10). The spindle drive has a linearly displaceable threaded spindle (27). The spindle drive (20) is in the form of a roller screw drive. The roller screw drive has a firs efficiency in the driving direction and a second different efficiency in the reverse-driving direction.

A linear actuator having a free fall function. The linear actuator moves a piston-rod member back and forth using torque of a rotary motor. Here, the piston-rod member is disposed within a portion of a cylinder body to be movable back and forth. In the event of jamming in which the piston-rod member is stopped due to sticking between an operating nut and a screw member, the piston-rod member is caused to freely fall in a direction in which load is applied. This can consequently obtain the maximum stretched length of the piston-rod member, thereby providing safety in an emergency.