An in-wheel drive device includes: a wheel bearing including a hub; and a speed reducer at least partially disposed in an internal space of the wheel bearing. The speed reducer includes: planet gears; a ring gear configured to engage the planet gears; and a carrier coupled to the planet gears and configured to transmit, to an outside of the in-wheel drive device, power generated by a revolution of the plurality of planet gears. A first sealing part is disposed in a region in which the carrier and the wheel bearing face each other.

An in-wheel drive device includes: a wheel bearing including a hub and an outer race spaced apart outward in a radial direction from the hub; and a speed reducer including a ring gear coupled to the wheel bearing. An outer surface of the ring gear, in the radial direction, and an inner surface of the wheel bearing, in the radial direction, adjoin to define first and second regions. The ring gear includes a protruding portion disposed on the outer surface of the ring gear in the second region and having a shape protruding toward the inner surface of the wheel bearing. The wheel bearing includes a recessed portion disposed on the inner surface of the wheel bearing in the second region and having a shape corresponding to a shape of the protruding portion. The protruding portion and the recessed portion engage each other in the second region.

A hub motor assembly includes a hub axle, a hub shell, a motor unit, a cycloidal speed reducer, and a one-way clutch unit. When an output shaft of the motor unit rotates in a first direction about an axial line, a cycloidal wheel of the cycloidal speed reducer is driven to produce an eccentric cycloidal motion relative to the axial line, to thereby drive rotation of the hub shell in the first direction. When the output shaft rotates in a second direction opposite to the first direction, the hub shell is prevented from rotating with the output shaft.

A bicycle hub assembly comprises a hub axle, a hub body, a sprocket support body, and a freewheel structure. The sprocket support body includes at least ten external spline teeth configured to engage with a bicycle rear sprocket assembly. Each of the at least ten external spline teeth has an external-spline driving surface and an external-spline non-driving surface. The freewheel structure includes a first ratchet member and a second ratchet member. The first ratchet member includes at least one first ratchet tooth. The second ratchet member includes at least one second ratchet tooth configured to engage with the at least one first ratchet tooth in a torque transmitting manner.

A bicycle hub assembly comprises a hub axle, a hub body, a sprocket support body, and a freewheel structure. The sprocket support body includes at least ten external spline teeth configured to engage with a bicycle rear sprocket assembly. Each of the at least ten external spline teeth has an external-spline driving surface and an external-spline non-driving surface. The freewheel structure includes a first ratchet member and a second ratchet member. The first ratchet member includes at least one first ratchet tooth. The second ratchet member includes at least one second ratchet tooth configured to engage with the at least one first ratchet tooth in a torque transmitting manner.

A conical shaped bicycle cassette has a unitary sprocket assembly. Each annular portion of an individual sprocket is mechanically supported either from a back of the sprocket, in an axial direction toward a bicycle hub or from an inner radial direction toward a centerline axis of the bicycle cassette and hub. The axial support zones and radial support zones are alternated around a circumference of the sprocket so that an entirety of the sprocket is supported in either the axial direction or the radial direction. In this way, the chain driving loads on the cassette are spread throughout the entire cassette and the areas of highly localized stress from the cassette are removed.

A conical shaped bicycle cassette has a unitary sprocket assembly. Each annular portion of an individual sprocket is mechanically supported either from a back of the sprocket, in an axial direction toward a bicycle hub or from an inner radial direction toward a centerline axis of the bicycle cassette and hub. The axial support zones and radial support zones are alternated around a circumference of the sprocket so that an entirety of the sprocket is supported in either the axial direction or the radial direction. In this way, the chain driving loads on the cassette are spread throughout the entire cassette and the areas of highly localized stress from the cassette are removed.

A bicycle hub assembly comprises a hub axle, a hub shell, a sprocket support body, a first ratchet member, a second ratchet member, a first biasing member, at least one receiving member, and a second biasing member. The first ratchet member is provided between the second ratchet member and the first biasing member in an axial direction. The at least one receiving member is provided between the first ratchet member and the first biasing member in a radial direction with respect to a rotational axis. The at least one receiving member includes a radially receiving part having a radially outer surface. The second biasing member contacts the radially outer surface of the radially receiving part to bias the radially receiving part toward the rotational axis in the radial direction.

A bicycle rear sprocket assembly comprises at least one sprocket having a total tooth number that is equal to or larger than 15. The at least one sprocket includes at least ten internal spline teeth configured to engage with a bicycle hub assembly.

A bicycle component for an at least partially muscle-powered bicycle with at least one freewheel unit including a freewheel component and a support unit and a spring unit, the freewheel component containing a tubular body section extending around a central axis and configured hollow showing a non-round outer contour for non-rotatable and axially displaceable coupling and a front surface with axial engagement components. The spring unit urges the freewheel component and the support unit apart in an axial direction of the central axis. The freewheel component, the support unit, and the spring unit form an assembly suitable for pre-assembly, and the spring unit is attached to the freewheel component and the support unit.