A clamping body freewheel unit and a drive device for motor-assisted driving of an electric bicycle having a clamping body freewheel unit. The clamping body freewheel unit includes a plurality of clamping bodies by which force transmission between an inner shaft and an outer shaft, coupled together via the clamping body freewheel unit, is allowed only in one of two opposite directions of rotation, a cage by which the plurality of clamping bodies of the clamping body freewheel unit are kept together at a defined spacing in a circumferential direction, and a plurality of rolling elements by which the inner and outer shafts are mounted rotatable relative to one another when the inner and outer shafts are coupled together via the clamping body freewheel unit, wherein at least some of the plurality of rolling elements and the clamping bodies are held jointly on the cage.

The invention relates to a freewheeling element comprising a cage, a plurality of clamping bodies, each of the clamping bodies being received in an associated clamping body pocket formed in the cage, and a plurality of rolling bodies, each of the rolling bodies being received in an associated rolling body pocket formed in the cage, the cage having a higher resilience than the clamping bodies and the rolling bodies.

A clutch has an inner race, an outer race spaced from the inner race and forming a radial cavity between the races, and a plurality of sprags disposed in the radial cavity. The sprags have a different coefficient of thermal expansion (CTE) from the inner race, the outer race, or both races, and a sprag cage retains the sprags at a uniform spacing within the radial cavity. When the clutch is at a first temperature, a gap exists between the sprags and the inner race, between the sprags and the outer race, or between the sprags and both races, and the clutch is disengaged. When the clutch is at a second temperature the sprags are in contact with both the races, and the clutch is engaged.

To provide a simple-structured cam clutch that does not require precise control, uses a smaller drive force for forcibly changing cam postures, and provides improved clutch operation stability and high responsiveness. The cam clutch includes a plurality of cams circumferentially arranged between an inner race and an outer race and supported by a cage member, and a selector allowing a rotation angle thereof to be controlled relatively to the inner race or the outer race to which the cage member is fixed. The selector has a cam posture control surface in contact with cam surfaces of the cams and capable of causing the cams to change posture thereof. The cam posture control surface includes a cam release portion radially protruded toward the cams more than a cam actuator portion and causing the cams to change posture thereof to a non-operating posture.

A clamping body freewheel unit and a drive device for motor-assisted driving of an electric bicycle having a clamping body freewheel unit. The clamping body freewheel unit includes a plurality of clamping bodies by which force transmission between an inner shaft and an outer shaft, coupled together via the clamping body freewheel unit, is allowed only in one of two opposite directions of rotation, a cage by which the plurality of clamping bodies of the clamping body freewheel unit are kept together at a defined spacing in a circumferential direction, and a plurality of rolling elements by which the inner and outer shafts are mounted rotatable relative to one another when the inner and outer shafts are coupled together via the clamping body freewheel unit, wherein at least some of the plurality of rolling elements and the clamping bodies are held jointly on the cage.

A clutch has an inner race, an outer race spaced from the inner race and forming a radial cavity between the races, and a plurality of sprags disposed in the radial cavity. The sprags have a different coefficient of thermal expansion (CTE) from the inner race, the outer race, or both races, and a sprag cage retains the sprags at a uniform spacing within the radial cavity. When the clutch is at a first temperature, a gap exists between the sprags and the inner race, between the sprags and the outer race, or between the sprags and both races, and the clutch is disengaged. When the clutch is at a second temperature the sprags are in contact with both the races, and the clutch is engaged.

To provide a simple-structured cam clutch that does not require precise control, uses a smaller drive force for forcibly changing cam postures, and provides improved clutch operation stability and high responsiveness. The cam clutch includes a plurality of cams circumferentially arranged between an inner race and an outer race and supported by a cage member, and a selector allowing a rotation angle thereof to be controlled relatively to the inner race or the outer race to which the cage member is fixed. The selector has a cam posture control surface in contact with cam surfaces of the cams and capable of causing the cams to change posture thereof. The cam posture control surface includes a cam release portion radially protruded toward the cams more than a cam actuator portion and causing the cams to change posture thereof to a non-operating posture.

The present invention aims at providing a cam clutch that realizes a reduction in production cost, improves productivity and assemblability, and increases the degree of design freedom. The cam clutch includes: an inner race and an outer race that are coaxial and rotatable relative to each other; a plurality of cams circumferentially arranged between the inner race and the outer race; and positioning members that keep each two adjacent cams at fixed positions relative to each other. The positioning members are configured to link each two adjacent cams such as to be tiltable independently of each other.

A wedge clutch includes first and second races supported for rotation about a common axis. The first race defines a cam surface and circumferentially arranged pockets recessed into the cam surface. A wedge element is formed of circumferentially arranged wedges each having an ear disposed in one of the pockets. Resilient members are disposed in the pockets and act between the ears to bias the wedge element to a contracted position in which the wedge elements collectively contract towards the axis and the clutch is engaged. A cage is axial movable towards the wedge element to engage with the ears to compress the resilient members and move the wedge element to an expanded position in which the wedge elements collectively expand away from the axis and the clutch is disengaged.

The invention relates to a freewheeling element comprising a cage, a plurality of clamping bodies, each of the clamping bodies being received in an associated clamping body pocket formed in the cage, and a plurality of rolling bodies, each of the rolling bodies being received in an associated rolling body pocket formed in the cage, the cage having a higher resilience than the clamping bodies and the rolling bodies.