A motor assembly includes a shaft, an electric motor operatively connected to the shaft to drive the shaft in a first rotational direction, a clutch assembly connected to the shaft, and a fan connected to the clutch assembly and configured to supply the electric motor with cooling air. The clutch assembly drives the fan when the electric motor drives the shaft and allows the fan to freewheel in the first rotational direction when the electric motor is not driving the shaft. A method of operating a fan cooled electric motor includes energizing the electric motor to drive a shaft in a first rotational direction using the electric motor and de-energizing the electric motor so that it no longer drives the shaft, allowing the fan to freewheel in the first rotational direction.

A motor assembly includes a shaft, an electric motor operatively connected to the shaft to drive the shaft in a first rotational direction, a clutch assembly connected to the shaft, and a fan connected to the clutch assembly and configured to supply the electric motor with cooling air. The clutch assembly drives the fan when the electric motor drives the shaft and allows the fan to freewheel in the first rotational direction when the electric motor is not driving the shaft. A method of operating a fan cooled electric motor includes energizing the electric motor to drive a shaft in a first rotational direction using the electric motor and de-energizing the electric motor so that it no longer drives the shaft, allowing the fan to freewheel in the first rotational direction.

A wedge clutch, including: outer and inner races; a wedge plate radially between the inner and outer races; and an electromagnetic actuator. The electromagnetic actuator includes: a coil; a first coil core piece including a first end disposed within the coil and a second end connected to the wedge plate; and a second coil core piece including a first end disposed within the first coil and a second end connected to the wedge plate. In a locked mode of the clutch, the inner race and outer races and the wedge plate are non-rotatably connected for rotation of the inner race in a circumferential direction. In a free-wheel mode of the clutch, the inner race is rotatable, with respect to the outer race, in the circumferential direction. To transition from the locked mode to the free-wheel mode, the electromagnetic actuator is arranged to be energized to radially contract the wedge plate.

A wedge clutch includes a first race rotatable about an axis and having first tapered surfaces annularly arranged about the axis, and a second race rotatable about the axis and concentric with the first race, the second race having a circumferential groove. A plurality of wedge segments are annularly arranged about the axis, each wedge segment having a second tapered surface contacting one of the first tapered surfaces. A plurality of pawls extend radially through at least a portion of either the first race or the second race. Each pawl is circumferentially aligned with a respective gap between two adjacent wedge segments. An actuating ring is configured to move axially along the axis. Axial movement of the actuating ring engages the pawls to force each pawl radially into the respective gap to separate the two adjacent wedge segments.

A radial wedge clutch, including: an axis of rotation; a shaft; an outer ring located radially outward of the shaft; a cage radially disposed between the shaft and the outer ring; a plurality of circumferentially aligned wedge plate segments radially disposed between the shaft and the outer ring; at least one resilient element urging the plurality of circumferentially aligned wedge plate segments radially outwardly; and an actuation plate axially displaceable in a first axial direction to engage the cage and rotate the cage and the plurality of circumferentially aligned wedge plate segments.

A radial wedge clutch, including: an axis of rotation; a shaft; an outer ring located radially outward of the shaft; a cage radially disposed between the shaft and the outer ring; a plurality of circumferentially aligned wedge plate segments radially disposed between the shaft and the outer ring; at least one resilient element urging the plurality of circumferentially aligned wedge plate segments radially outwardly; and an actuation plate axially displaceable in a first axial direction to engage the cage and rotate the cage and the plurality of circumferentially aligned wedge plate segments.

A switchable wedge clutch includes an inner race, and an outer race that has an inner surface defining a plurality of tapered regions. A plurality of wedge plate are disposed between the inner and outer races, and are moveable circumferentially about the inner race. Each wedge plate segment has a tapered outer surface configured to engage and slide relative to the tapered regions of the outer race. An actuating ring has a plurality of axially-extending tapered fingers configured to fit between two of the wedge plate segments. The wedge plate segments are wedged between the tapered regions and the inner race to lock the inner and outer race together. Axial movement of the actuating ring forces the wedge plate segments circumferentially against biasing forces of springs to unwedge the wedge plate segments from between the outer race and the inner race and unlock the wedge clutch.

A wedge clutch includes a first race rotatable about an axis and having first tapered surfaces annularly arranged about the axis, and a second race rotatable about the axis and concentric with the first race, the second race having a circumferential groove. A plurality of wedge segments are annularly arranged about the axis, each wedge segment having a second tapered surface contacting one of the first tapered surfaces. A plurality of pawls extend radially through at least a portion of either the first race or the second race. Each pawl is circumferentially aligned with a respective gap between two adjacent wedge segments. An actuating ring is configured to move axially along the axis. Axial movement of the actuating ring engages the pawls to force each pawl radially into the respective gap to separate the two adjacent wedge segments.

A clutch assembly for selectively transmitting torque between an engine and a torque converter is provided. A first plate is non-rotatably connected to a torque converter cover. A second plate is configured to receive a torque input from an engine. A wedge clutch is disposed axially between the first and second plates and is configured to selectively transfer torque between the first plate and the second plate. The wedge clutch includes wedge segments that are configured to collectively radially expand and contract to selectively transfer torque between the first plate and the second plate.

A clutch mechanism, for use in a rotary power tool having a motor, comprises an input member to which torque from the motor is transferred and an output member co-rotatable with the input member, the output member defining a rotational axis. The clutch mechanism further comprises a cam surface formed on one of the input member or the output member and a compression spring carried by the other of the input member or the output member for co-rotation therewith. The clutch mechanism also comprises a follower having a circular cross-sectional shape biased against the cam surface by the compression spring. In response to relative rotation between the input member and the output member, the cam surface displaces the follower along a line of action coaxial or parallel with the spring. The line of action does not intersect the rotational axis.