When relative positions of cages are changed from first positions to second positions, rollers are moved toward each other against an elastic biasing force of an elastic member such that an off state is achieved in which the rollers are disengaged from a cam surface or an inner peripheral surface portion to have a clearance therefrom. When the relative positions of the cages are changed from the second positions to the first positions, the rollers are moved away from each other by the elastic biasing force such that an on state is achieved in which one of the rollers on a downstream side engages with the cam surface or the inner peripheral surface portion without any clearance while the other of the rollers on an upstream side has a clearance from the cam surface or the inner peripheral surface portion.

A controllable one-way clutch assembly having an electromagnetic actuator module equipped with an energizeable coil assembly, a strut moveable in response to energization of the coil assembly from a released position to a locked position, and a latching mechanism operable to releaseably hold the strut in the released position when the coil assembly is not energized.

A controllable one-way clutch assembly having an electromagnetic actuator module equipped with an energizeable coil assembly, a strut moveable in response to energization of the coil assembly from a released position to a locked position, and a latching mechanism operable to releaseably hold the strut in the released position when the coil assembly is not energized.

An actuator controller to controllably supply DC power to a bi-directional electromechanical actuator is provided. The controller includes a first circuit to receive power and direction command signals from a remote electronic control unit through a vehicle-based bus. Control logic is operative to determine a vehicle system failure and to generate a failsafe position command signal in the event of the failure. A failsafe power circuit controllably stores electrical power and supplies the stored electrical power based on the failsafe position command signal. A power switching and supply circuit supplies DC power of a desired polarity to the electromechanical actuator in response to the power and direction command signals in the absence of the failure and supplies the stored electrical power to the electromechanical actuator in the event of the failure.

An actuator controller to controllably supply DC power to a bi-directional electromechanical actuator is provided. The controller includes a first circuit to receive power and direction command signals from a remote electronic control unit through a vehicle-based bus. Control logic is operative to determine a vehicle system failure and to generate a failsafe position command signal in the event of the failure. A failsafe power circuit controllably stores electrical power and supplies the stored electrical power based on the failsafe position command signal. A power switching and supply circuit supplies DC power of a desired polarity to the electromechanical actuator in response to the power and direction command signals in the absence of the failure and supplies the stored electrical power to the electromechanical actuator in the event of the failure.

An inner peripheral surface of an outer cylindrical tubular portion and an outer peripheral surface of an inner cylindrical tubular portion of a rotor are respectively shaped into a stepped form. A radial distance between the outer cylindrical tubular portion and the inner cylindrical tubular portion at a counter-armature side location is larger than that of an armature side location in the rotor. An outer peripheral surface of an outer cylindrical tubular portion and an inner peripheral surface of an inner cylindrical tubular portion of a stator are respectively shaped into a stepped form. A radial distance between the outer peripheral surface of the outer cylindrical tubular portion and the inner peripheral surface of the inner cylindrical tubular portion at the counter-armature side location is larger than that of the armature side location in the stator.

An inner peripheral surface of an outer cylindrical tubular portion and an outer peripheral surface of an inner cylindrical tubular portion of a rotor are respectively shaped into a stepped form. A radial distance between the outer cylindrical tubular portion and the inner cylindrical tubular portion at a counter-armature side location is larger than that of an armature side location in the rotor. An outer peripheral surface of an outer cylindrical tubular portion and an inner peripheral surface of an inner cylindrical tubular portion of a stator are respectively shaped into a stepped form. A radial distance between the outer peripheral surface of the outer cylindrical tubular portion and the inner peripheral surface of the inner cylindrical tubular portion at the counter-armature side location is larger than that of the armature side location in the stator.

A clutch system includes a rotary input member, a wrap spring clutch and a rotary output member. The wrap spring clutch has a first end, a second end, and a plurality of coils. The stiffness of the wrap spring clutch is selected such that, when transmitting less than a selected coil engagement torque, the clutch system transmits torque helically from the rotary input member, to the second end, helically through the wrap spring clutch to the first end, and into the rotary output member. When transmitting more than the selected coil engagement torque, the clutch system transmits torque in parallel from the rotary input member, to the second end, helically through the wrap spring clutch to the first end, and into the rotary output member, and from the rotary input member through the coil engagement surface, to the first end, and into the rotary output member.

In an aspect, a clutch assembly is provided that uses an electromagnet to generate a magnetic circuit which drives an armature to a position whereat it engages the clutch to operatively connect a rotating member to a stationary member. In embodiments wherein the armature initially rotates with the rotating member, the magnetic circuit passes through the stationary member. In embodiments wherein the armature is initially stationary, the magnetic circuit extends through the rotating member.

In an aspect, a clutch assembly is provided that uses an electromagnet to generate a magnetic circuit which drives an armature to a position whereat it engages the clutch to operatively connect a rotating member to a stationary member. In embodiments wherein the armature initially rotates with the rotating member, the magnetic circuit passes through the stationary member. In embodiments wherein the armature is initially stationary, the magnetic circuit extends through the rotating member.