Power receiving unit, rotating component, process cartridge, and assembly and disassembly methods thereof

Power receiving unit, rotating component, process cartridge, and assembly and disassembly methods thereof are provided. The process cartridge is detachably mounted in an image formation apparatus configured with a swingable power output unit, an outer circumference of the power output unit contains a recessed portion, and the power receiving unit is engaged with the power output unit to receive a driving force. The power receiving unit comprises a wheel hub, a power receiving part, and a bias part. The wheel hub is disposed on an end of a rotating component in the process cartridge. The power receiving part includes a fixing protrusion and a notch that are oppositely disposed, the fixing protrusion is inserted into the recessed portion, and the notch provides a swinging space for the power output unit. The bias part provides a bias force toward the fixing protrusion for the power output unit.

FIELD OF THE DISCLOSURE

The present disclosure generally relates to the field of laser printing, and, more particularly, relates to a process cartridge including a power receiving unit and a rotating component, and methods for assembling and disassembling the process cartridge.

BACKGROUND

The present disclosure relates to a process cartridge. The process cartridge may be applied to an image formation apparatus based on an electrostatic printing technique. The image formation apparatus may be any one of a laser image formation apparatus, a LED image formation apparatus, a copying machine, and a fax machine.

The process cartridge may be detachably mounted in the image formation apparatus. A plurality of rotating components may be disposed in parallel along a length direction of the process cartridge. The rotating component may include a photosensitive component having a photosensitive layer for receiving irradiation of laser beam in the image formation apparatus to form an electrostatic latent image. The rotating component may also include a charging component for charging a surface of the photosensitive component to form uniform charge on the surface of the photosensitive component. In addition, the rotating component may include a developing component for transferring developer in the process cartridge to the electrostatic latent image region of the photosensitive component to form a visible developer image. Further, the rotating component may include components, e.g., a wheel hub or a gear, etc., for transmitting power in the process cartridge. Each component in the above-described rotating component may have to produce relative rotation when the process cartridge operates, which may desire to acquire a rotating driving force from the image formation apparatus.

In the prior art, a power receiving unit is often disposed at an axial end of the process cartridge to engage with a power output unit in the image formation apparatus to receive power. The power receiving unit in the process cartridge is set to be directly connected to a rotating component inside the process cartridge, and the rotational driving force is transmitted to any other rotating component through the rotating component. Alternatively, the rotational driving force is transmitted to a gear on a longitudinal end of the process cartridge through the power receiving unit, and then transmitted to any other rotating component inside the process cartridge through the gear.

FIGS. 1aand 1billustrate schematic diagrams of a process cartridge for receiving a driving force from an image formation apparatus. Referring toFIGS. 1aand 1b, the process cartridge7includes a rotating component1(e.g., a photosensitive component, a developing component, a powder feeding component, etc.). Two ends of the rotating component1are rotatably supported on a frame71of the process cartridge7. A power receiving unit570is disposed on an end of the rotating component1. The image formation apparatus is provided with a swingable power output unit101. After the process cartridge7is mounted into the image formation apparatus along a Z1direction (an axial direction of the rotating component1or a length direction of the process cartridge7), the power receiving unit570in the process cartridge7is engaged with a power output unit101in the image formation apparatus to receive the driving force, thereby driving the rotating component1to rotate.

FIG. 2aillustrates a cross-sectional view of the power receiving unit in the process cartridge and the power output unit in the image formation apparatus in an engaged state when transmitting the power. The power output unit101often has an overall cylindrical shape, and three radially concave recessed portions101aare disposed on an outer circumference101fthereof. The power receiving unit570in the process cartridge7has a hollow cylinder structure, and three claws573are disposed inside the hollow cylinder structure. A claws573is connected to the cylindrical inner wall of the hollow cylinder structure through an elastic arm574. The claws573are inserted into the recessed portions101a, respectively, to realize the engaged power transmission between the power receiving unit570in the process cartridge7and the power output unit101in the image formation apparatus.

FIG. 2billustrates a cross-sectional view of the power receiving unit in the process cartridge and the power output unit in the image formation apparatus in a state when not transmitting the power. Referring toFIG. 2b, when the process cartridge7is attached to or taken out from the image formation apparatus, the outer circumferential wall of the power output unit101pushes the claw573outward to prepare for the claw573entering the recessed portion101a, or to take out the claw573from the recessed portion101a. During such process, the elastic arm574provides elastic deformation force for the claw573. With such a structure, the elastic arm574is easily broken during the repeated disassembly and assembly of the process cartridge7. Once the elastic arm574is broken, the image formation apparatus cannot transmit power to the process cartridge7. The disclosed process cartridge, assembly and disassembly methods thereof are directed to solve one or more problems set forth above and other problems in the art.

BRIEF SUMMARY OF THE DISCLOSURE

One aspect of the present disclosure includes a power receiving unit of a process cartridge. The process cartridge is detachably mounted in an image formation apparatus configured with a power output unit that is swingable, an outer circumference of the power output unit contains a recessed portion, and the power receiving unit is engaged with the power output unit to receive a driving force. The power receiving unit includes a wheel hub, and the wheel hub is disposed on an end of a rotating component in the process cartridge to transmit the driving force to the rotating component. The power receiving unit also includes a power receiving part mounted inside the wheel hub. The power receiving part includes a fixing protrusion and a notch that are oppositely disposed, the fixing protrusion is inserted into the recessed portion, and the notch provides a swinging space for the power output unit. Further, the power receiving unit includes a bias part, and the bias part provides a bias force toward the fixing protrusion for the power output unit.

Another aspect of the present disclosure includes a rotating component. The rotating component includes an end disposed with a power receiving unit including the above-described power receiving unit.

Another aspect of the present disclosure includes a process cartridge comprising a frame and the above-described rotating component. Two ends of the rotating component are rotatably supported on the frame through a supporting component.

Another aspect of the present disclosure includes a power receiving unit of a process cartridge. The process cartridge is detachably mounted in an image formation apparatus configured with a power output unit that is swingable, an outer circumference of the power output unit contains a recessed portion, and the power receiving unit is engaged with the power output unit to receive a driving force. The power receiving unit includes a fixing protrusion. The fixing protrusion is disposed inside the power receiving unit, and the fixing protrusion is engaged with the recessed portion of the power output unit to receive the driving force. When the power receiving unit moves along an axial direction thereof and is in a contact engagement with the power output unit, the fixing protrusion abuts against a front end of the power output unit to cause the power output unit to be tilted and swung.

Another aspect of the present disclosure includes a power receiving unit of a process cartridge. The process cartridge is detachably mounted in an image formation apparatus configured with a power output unit that is swingable, an outer circumference of the power output unit contains a recessed portion, and the power receiving unit is engaged with the power output unit to receive a driving force. The power receiving unit includes a fixing protrusion. The fixing protrusion is disposed inside the power receiving unit, and the fixing protrusion is engaged with the recessed portion of the power output unit to receive the driving force. When the power receiving unit moves along an axial direction thereof and is disengaged from the power output unit, the fixing protrusion abuts against the recessed portion of the power output unit to cause the power output unit to be tilted and swung.

Another aspect of the present disclosure includes a process cartridge. The process cartridge is disposed with the above-described power receiving unit.

Another aspect of the present disclosure includes a method for assembling a process cartridge. The process cartridge is detachably mounted in an image formation apparatus configured with a power output unit that is swingable, an outer circumference of the power output unit contains a recessed portion, and the power receiving unit is engaged with the power output unit to receive a driving force. The power receiving unit includes a fixing protrusion. The fixing protrusion is disposed inside the power receiving unit, and the fixing protrusion is engaged with the recessed portion of the power output unit to receive the driving force. The method for assembling the process cartridge includes the following. When the process cartridge is mounted into the image formation apparatus along a length direction of the process cartridge or an axial direction of the power receiving unit, the power receiving unit is in a contact with the power output unit, and the fixing protrusion abuts against a front end of the power output unit to cause the power output unit to be tilted and swung.

Another aspect of the present disclosure includes a method for disassembling a process cartridge. The process cartridge is detachably mounted in an image formation apparatus configured with a power output unit that is swingable, an outer circumference of the power output unit contains a recessed portion, and the power receiving unit is engaged with the power output unit to receive a driving force. The power receiving unit includes a fixing protrusion. The fixing protrusion is disposed inside the power receiving unit, and the fixing protrusion is engaged with the recessed portion of the power output unit to receive the driving force. The method for disassembling the process cartridge includes the following. When the process cartridge is taken out from the image formation apparatus along a length direction of the process cartridge or an axial direction of the power receiving unit, the power receiving unit is disengaged from the power output unit, and the fixing protrusion abuts against the recessed portion of the power output unit to cause the power output unit to be tilted and swung.

In the disclosed embodiments, in one aspect, through a disposure of a fixing protrusion that is engaged with the recessed portion, the structure may be stable, and may be less likely to be broken, thereby ensuring substantially stable power transmission. In another aspect, the cooperation of the notch and the fixing protrusion may provide a tilting displacement space for the installation and insertion process and the disassembly and removal process of the power output unit in the image formation apparatus and the power receiving unit in the process cartridge, which may avoid interference or inaccessibility issue, and ensure smooth installation and removal. In another aspect, the bias part may improve the stability of the engagement power transmission process.

DETAILED DESCRIPTION

The present disclosure provides a power receiving unit disposed on a process cartridge for receiving a driving force from an image formation apparatus and transmitting the driving force to a rotating component in the process cartridge. The disclosed power receiving unit may be quickly, reliably, and stably engaged to a power output unit in the image formation apparatus to receive the driving force.

In one embodiments, an axial (a length) direction of the process cartridge may be substantially coaxial or parallel to a rotary shaft of a developing component. A mounting direction for mounting the process cartridge into an electronic imaging apparatus may be the same as the axial (length) direction of the process cartridge or an axial direction of the rotary shaft of the developing component. A direction for disassembling (detaching) the process cartridge from the electronic imaging apparatus may be opposite to the mounting direction of the process cartridge.

FIG. 3illustrates a perspective view of the power receiving unit of the process cartridge consistent with disclosed embodiments of the present disclosure; andFIG. 4illustrates an exploded perspective view of the power receiving unit. Referring toFIG. 3andFIG. 4, the power receiving unit may include a wheel hub10, a power receiving part20and a bias part30. The wheel hub10may be fixed to an end of a rotating component in the process cartridge to transmit a driving force to the rotating component. The power receiving part20may be mounted inside the wheel hub10, and a fixing protrusion21, which is engaged with a recessed portion of the power output unit in the image formation apparatus, may be disposed on the inner wall of the power receiving part20. The power receiving part20may further include a notch22, and the notch22may be disposed opposite to the fixing protrusion21. The notch22may provide a certain swinging space for a power output unit101. The bias part30may be disposed on a side where the notch22is located, and may provide a bias force toward the fixing protrusion21for the power output unit in the image formation apparatus.

In one embodiment, a quantity of the fixing protrusions21may be one or two. For illustrative purposes, two fixing protrusions are used as an example in the disclosed embodiments. The bias part30may be a component having an elastic function, e.g., a tension spring, a rubber band, a torsion spring, or a leaf spring, etc. Alternatively, the bias part may be a pair of magnets, etc. For illustrative purposes, a torsion spring is used as an example in the disclosed embodiments.

FIG. 5illustrates a schematic diagram for assembling a power receiving part and a bias part consistent with disclosed embodiments of the present disclosure. Referring toFIG. 5, a mounting portion23for mounting the bias part30and an abutting portion24abutted against a short side31of the bias part30may be disposed on an end of the notch22. A slit25for providing a movable space for a long side32of the bias part30may be disposed on another end of the notch22.

FIG. 6aillustrates a cross-sectional view of the power receiving unit in the process cartridge and the power output unit in the image formation apparatus in an engaged state when not transmitting the driving force consistent with disclosed embodiments of the present disclosure.FIG. 6billustrates a cross-sectional view of the power receiving unit in the process cartridge and the power output unit in the image formation apparatus in an engaged state when transmitting the driving force consistent with disclosed embodiments of the present disclosure. Referring toFIGS. 6aand 6b, when mounting the process cartridge into the image formation apparatus, the power output unit101may be inserted into the power receiving part20. The positions of the fixing protrusion21and a recessed portion101amay be arbitrary, for illustrative purposes, the relative positions of the fixing protrusion21and the recessed portion101aare shifted as an example.

In a process of inserting the power output unit101into the power receiving part20and after the insertion is completed, the power output unit101and the power receiving part20may be in a state illustrated inFIG. 6a. In view of this, the power output unit101may be topped by the fixing protrusion21toward the bias part30, and the long side32of the bias part30may apply a force toward the fixing protrusion21side on the power output unit101. When the power output unit101is rotated along a ‘A’ direction until the fixing protrusion21reaches a position coincided with the recessed portion101a, the fixing protrusion21may be caught in the recessed portion101aunder the restoring force of the bias part30(as illustrated inFIG. 6b), and the power receiving unit in the process cartridge may rotate along the ‘A’ direction together with the power output unit101in the image formation apparatus. When the power receiving unit is detached from the power output unit101, because the power output unit101in the image formation apparatus can swing and the bias part30is disposed, the fixing protrusion21may be axially detached from the recessed portion101ato disengage.

Guide bevels (an inclined surface or a curved surface) may be disposed on the front and rear (axial direction) ends of the fixing protrusion21, such that the fixing protrusion21may be smoothly inserted into or detached from the recessed portion101a.

The difference between the present embodiment and the above-described embodiment may include that the bias part in the present embodiment may be disposed on the inner wall of the wheel hub.

FIG. 7illustrates a cross-sectional view of a power receiving unit in the process cartridge and a power output unit in the image formation apparatus in an engaged state when transmitting the driving force consistent with disclosed embodiments of the present disclosure. The bias part30amay be disposed on the inner wall of the wheel hub10. In one embodiment, the bias part30amay be an elastic structure integrally formed with the wheel hub10. In another embodiment, the bias part30amay be a separately installed elastic part. The bias part30amay be disposed on a side opposite to the fixing protrusion21.

In the above-described embodiments, the bias part may be a component having an elastic function, e.g., a tension spring, a rubber band, a torsion spring, or a leaf spring, etc. Alternatively, the bias part may be a pair of magnets, etc. The wheel hub10may be integrally formed with the power receiving part20. A holder11of the wheel hub10may be fixedly connected to a rotating component, e.g., a photosensitive component (photosensitive drum), in the process cartridge. The power receiving unit may be fixed to the frame of the process cartridge by a supporting component.

FIGS. 8-9illustrates schematic diagrams of the power receiving unit in the process cartridge. The parts that are not described in detail in the Embodiment 3 may refer to the descriptions associated with structures, functions, and operations of the same or similar parts in the above-described embodiments, which are not repeated herein.

Processing Cartridge

Referring toFIG. 8, the power receiving unit a100may be disposed on one end of the process cartridge aC in the axial (length) direction. The power receiving unit a100may be mounted into the image formation apparatus along a direction Z1to engage with the power output unit101to receive the rotational driving force and transmit the rotational driving force to the rotating component in the process cartridge aC to make it rotated.

Power Receiving Unit

Referring toFIGS. 9-12a, the power receiving unit a100may include a wheel hub a120, a power receiving part a110, and a bias part a130. The wheel hub a120may be directly or indirectly connected to the rotating component in the process cartridge aC to transmit a driving force to the rotating component. The wheel hub a120may have a hollow cylindrical structure, and may include an inner hole a115. The power receiving part a110may be disposed inside the wheel hub a120. A trapezoidal shaped fixing protrusion a111may be disposed on the inner wall of the power receiving part a110. The fixing protrusion a111may be disposed around the rotary shaft of the power receiving part a110. A quantity of the fixing protrusions a111may be one or two.

As viewed from the axial direction of the power receiving unit a100, referring toFIG. 10, a guide bevel a111amay be formed on the outward end (front end) of the fixing protrusion a111, and another guide bevel a111bmay be formed on the inward end (rear end) thereof. As viewed from the end direction of the power receiving unit a100, referring toFIGS. 11-12a, a substantially upright engagement side a111cmay be formed on a side of the fixing protrusion a111, and a guide bevel a111dmay be formed on another side of the fixing protrusion a111. A notch a112may be formed inside the power receiving part a110and opposite to the fixing protrusion a111. A minimum distance of the notch a112is W3. The bias part a130may be disposed on the wheel hub a120, and may be inserted into the contour of the wheel hub a120through an intermediate “U”-shaped structure. One side (short side) a131of the bias part a130may be fixed to the protrusion of the outer surface of the wheel hub a120, and another side (long side) a132of the bias part a130may be disposed on the inside the wheel hub a120. The side (long side) a132of the bias part a130may be extended into the notch a112of the power receiving part a110. As viewed from the end direction of the power receiving unit a100, the side (long side) a132may be disposed opposite to the fixing protrusion a111, and a portion (the side (long side) a132) of the bias part a130may be overlapped with the notch a112.

Power Output Unit

Referring toFIG. 13, the power output unit101in the image formation apparatus may be coupled to one side of a gear base150, and a mounting post151may be disposed on the other side of the gear base150. Referring toFIG. 14, the mounting post151of the gear base150may be rotatably coupled to a holder P11disposed on an outer frame of the image formation apparatus. The middle part (cylindrical) of the gear base150may pass through an inner frame P12of the image formation apparatus. A reset elastic part152may be disposed inside the gear base150. The reset elastic part152may enable the power output unit101and the gear base150to be integrally expanded and contracted along the axial direction thereof with respect to the inner frame P12. At the same time, because the aperture W2of the inner frame P12is larger than the middle part W1of the gear base150, the power output unit101may have a certain radial movement space for substantially swinging in the image formation apparatus. The power output unit101may be tilted with respect to the inner frame P12when being subjected to an external force. When the external force is removed, the reset elastic part152may enable the power output unit101to be restored from the tilted state to the initial state.

Referring toFIG. 15, the power output unit101may often have an overall cylindrical shape, and three radially concave recessed portions101amay be disposed on the outer circumference of the power output unit101. An arc-shaped protrusion portion101bmay be disposed on the front end of the power output unit101. A guide bevel101cmay be formed on one end of the recessed portion101aclose to the protrusion portion101b. A diameter of the front end of the power output unit101is W4.

Contact Engagement Between the Power Receiving Unit and the Power Output Unit

FIGS. 16-18billustrate schematic diagrams of a contact engagement between the power receiving unit a100in the process cartridge and the power output unit101in the image formation apparatus. When the power receiving unit a100is mounted into the image formation apparatus along the direction Z1(axial direction) and is in contact engagement with the power output unit101, the protrusion portion101bon the front end of the power output unit101may first abut against the guide bevel a111aof the fixing protrusion a111. The power output unit101may swing to a certain extent, and the minimum distance W3of the notch a112may be greater than or equal to the diameter W4of the power output unit101. With the continuation of the mounting movement of the process cartridge C, the guide bevel a111aof the fixing protrusion a111may push the protrusion portion101bof the power output unit101to cause the power output unit101to be tilted by the external force and to be moved toward the notch a112. In view of this, a rotation axis of the power output unit101may be inclined with respect to a rotation axis of the power receiving unit a100(there is an inclination angle R1).

In the above-described mounting process, the guide bevel a111aof the fixing protrusion a111may cause the power output unit101to be tilted, thereby avoiding structural interference between the power output unit101and the fixing protrusion a111. Referring toFIG. 17b, after mounting the power receiving unit a100, even if the fixing protrusion a111and the recessed portion101ahave a staggered relative position and are not engaged, after the motor drives the power output unit101to rotate counterclockwise, the recessed portion101aof the power output unit101may move to a position corresponding to the fixing protrusion a111, and the cylindrical surface of the power output unit101may no longer abut against the fixing protrusion a111. In view of this, the reset elastic part152in the gear base150may enable the power output unit101to be restored from the tilt state to the initial state. The fixing protrusion a111may be caught into the recessed portion101ato receive the rotational driving force, as illustrated inFIG. 18b.

Disengagement Between the Power Receiving Unit and the Power Output Unit

FIG. 19illustrates a schematic diagram of a disengagement between the power receiving unit a100in the process cartridge and the power output unit101in the image formation apparatus. Referring toFIG. 19, when the power receiving unit a100moves along the direction Z2(reverse of the direction Z1) to be disengaged from the power output unit101in the image formation apparatus, the guide bevel a111bof the fixing protrusion a111may abut against the guide bevel101cin the recessed portion101aof the power output unit101. With the continuation of the detaching movement of the process cartridge C, the guide bevel a111bmay push the guide bevel101cto enable the power output unit101to be tilted by the external force and to be moved toward the notch a112. In view of this, a rotation axis of the power output unit101may be inclined with respect to a rotation axis of the power receiving unit a100(there is an inclination angle R2). With the tilting movement of the power output unit101, the fixing protrusion a111may be disengaged from the recessed portion101a. When the power output unit101is no longer in contact with the fixing protrusion a111, the power output unit101may be restored from the tilted state to the initial state under the action of the reset elastic part152.

In addition, during the above-described process (contact engagement between the power receiving unit and the power output unit), referring toFIGS. 17a-18b, through auxiliary disposure of the bias part a130, after the power output unit101abuts against the fixing protrusion a111and is tilted, the side a132(long side) of the bias part a130may be deformed by the thrust of the power output unit101. When the recessed portion101aof the power output unit101moves to a position corresponding to the fixing protrusion a111, the side a132(long side) of the bias part a130may apply an elastic force to push the cylindrical surface of the power output unit101to enable the power output unit101to be moved toward the fixing protrusion a111.

At the same time, in the process of engagement between the power receiving unit and the power output unit for receiving the power, the side a132(long side) of the bias part a130may also apply the elastic force to push the cylindrical surface of the power output unit101to enable the fixing protrusion a111of the power receiving unit a100to be not disengaged from the recessed portion101aof the power output unit101.

Moreover, in the process cartridge aC, referring toFIG. 8, a convex power receiving unit a200may be disposed on a same end as the power receiving unit a100. The convex power receiving unit a200may be engaged with a concave power output unit201to receive the rotational driving force. The power receiving unit a100and the convex power receiving unit a200may be separately independent units to drive the respective rotating components to rotate. In one embodiment, the power receiving unit a100may drive the photosensitive component a10to rotate, and the convex power receiving unit a200may drive the developing component a20to rotate.

Further, to make the relative rotation substantially stable, a quantity of components in the process cartridge may be reduced, and the convex power receiving unit a200may be eliminated. Referring toFIG. 20, a pair of transfer parts a11and a21(gears) may be added on one end of the photosensitive component a10and the developing component a20. Through the disposure of the transfer parts a11and a21, the power receiving unit a100may simultaneously drive the photosensitive component a10and the developing component a20to rotate after receiving the rotational driving force from the power output unit101. Referring toFIG. 21, the transfer parts a11and a21may be disposed on the same end as the power receiving unit a100, and the transfer part a11may be integrally disposed with the power receiving unit a100. Further, referring toFIGS. 22-23, the transfer parts a11and a21(gears) may be replaced by a belt a30, an inner side of the belt a30may be sleeved on an outer side of the power receiving unit a100, and another inner side of the belt a30may be sleeved on the axial center of the developing part a20. The belt a30may be disposed on one end (driving end or conductive end) or both ends of the photosensitive component a10and the developing component a20.

FIGS. 24-25illustrate perspective views of the power receiving unit in the process cartridge consistent with disclosed embodiments of the present disclosure. The power receiving part20cmay be mounted inside the wheel hub10cand on the base11c. An elastic part12cmay be disposed between the base11cand the power receiving part20cto enable the power receiving part20cto be expanded and contracted along the axial direction of the rotational shaft of the power receiving unit and to translate with respect to the base11c.

FIG. 26illustrates a perspective view of the power receiving unit after removing the wheel hub10c, andFIG. 27illustrates a perspective view of the power receiving part20c. A fixing protrusion21cand a trapezoidal block22cmay be disposed on the power receiving part20c. The trapezoidal block22cmay be closer to the base11cthan the fixing protrusion21c. The trapezoidal block22cmay allow the power receiving part20cto translate inside the wheel hub10c.

A quantity of the fixing protrusions21cmay be at least one. In one embodiment, a quantity of the fixing protrusions21cmay be two. A quantity of the trapezoidal blocks22cmay be at least one, and the trapezoidal block22cmay have at least one inclined surface. In one embodiment, a quantity of the trapezoidal blocks22cmay be two (forming a cross-coaxial structure), and each trapezoidal block22cmay have two inclined surfaces. At the same time, the angle between every two inclined surfaces may be 90 degrees.

Similarly, other couplings may be used to replace the trapezoidal block22cin the disclosed embodiments, such that the power receiving part20cmay be fixed to the inside of the wheel hub10c, and the power receiving part20cmay translate inside the wheel hub10c.

FIG. 28illustrates a perspective view of another power receiving part20dconsistent with disclosed embodiments in the present disclosure. Referring toFIG. 28, the power receiving part20dmay include a fixing protrusion21d, a ball portion22d, and a transfer portion23d. In one embodiment, the transfer portion23dmay be located on the ball portion22dfor transmitting power to the wheel hub10c. The power receiving part20dillustrated inFIG. 28may be interchangeable with the power receiving part20cillustrated inFIG. 27.

A quantity of the fixing protrusions21dmay be at least one. In one embodiment, a quantity of the fixing protrusions21dmay be two. Similarly, a recessed hole for carrying the ball portion22dof the power receiving part20dmay be disposed on the base, such that the power receiving part20dmay rotate inside the wheel hub.