Transmission device and vehicle

Abstract

This transmission device is attached to an attachment target having a hub shaft, and includes an input member, a hub, and a transmission mechanism. The transmission mechanism transmits torque from the input member to the hub. The hub has an inner cylinder part provided on the radially inner side, an outer cylinder part provided on the radially outer side, and a connection part connecting the inner cylinder part and the outer cylinder part. The inner cylinder part is attached to the hub shaft, the hub is capable of rotating about the hub shaft, and the input member includes a sprocket. The transmission mechanism is disposed between the connection part and the sprocket in the axial direction of the hub shaft, is a multi-speed transmission mechanism, and includes a planetary gear mechanism. The planetary gear mechanism includes a sun gear, a plurality of planetary gears, a planetary carrier that connects the plurality of planetary gears, and a ring gear. The sun gear is connected to the input member so as to allow power transmission, and the ring gear is connected to the hub so as to allow power transmission.

Description

Transmission and vehicle

[0001] The present invention relates to a transmission and a vehicle equipped with the transmission.

[0002] In recent years, with the implementation of the "double carbon" strategy and the rapid development of the new energy field, new energy vehicles are increasingly favored by consumers due to their convenience, environmental friendliness, and low price. In the field of electric vehicles, which are typical new energy vehicles, especially in the fields of electric bicycles and electric motorcycles, a planetary gear mechanism may be used as a transmission. In electric vehicles, different requirements for rotational speed and torque are required in different situations. For example, low rotational speed and high torque are required when starting, and high rotational speed and low torque are required when the vehicle is traveling at high speed.

[0003] In a typical electric vehicle, such as an electric bicycle or electric motorcycle, a motor serving as a power source is installed in the center of the vehicle body in the longitudinal direction, i.e., between the front and rear wheels, and the power source transmits torque to the front or rear wheels via a transmission (chain, sprocket, speed change mechanism). In order to save space in such electric vehicles, it is desirable to make the transmission smaller and more compact, at least without reducing the gear ratio of the transmission.

[0004] The present invention has been made in view of the above circumstances, and has an object to provide a transmission device that is small and compact and can achieve a sufficiently large gear ratio, and also to provide a vehicle equipped with such a transmission device.

[0005] In order to achieve the above object, the present invention uses the following technical means.

[0006] According to one aspect of the present invention, a transmission device that is attached to an attachment object having a hub axle includes an input member, a hub, and a speed change mechanism, wherein the speed change mechanism transmits torque from the input member to the hub, the hub has an inner cylindrical portion provided radially inward, an outer cylindrical portion provided radially outward, and a connecting portion connecting the inner cylindrical portion and the outer cylindrical portion, the inner cylindrical portion is attached to the hub axle, the hub is rotatable around the hub axle, the input member includes a sprocket, the speed change mechanism is disposed between the connecting portion and the sprocket in the axial direction of the hub axle, and includes a planetary gear mechanism that includes a sun gear, a plurality of planet gears, a planet carrier connecting the plurality of planet gears, and a ring gear, the sun gear is connected to the input member, and the ring gear is connected to the hub.

[0007] According to one aspect of the present invention, a planetary gear mechanism with a sun gear as an input end and a ring gear as an output end is advantageous for enabling a speed change mechanism to achieve a large gear ratio in at least one gear, and the space near the hub can be utilized to house the transmission device, making the transmission device smaller and more compact.

[0008] Fig. 1 is a schematic side view of a vehicle according to an embodiment of the present invention. Fig. 2 is a schematic cross-sectional view of a transmission according to an embodiment of the present invention. Fig. 3 is a speed diagram showing a planetary gear mechanism in the first gear stage of the transmission according to the present invention. Fig. 4 is a speed diagram showing a planetary gear mechanism in the second gear stage of the transmission according to the present invention. Fig. 5 is a schematic topology diagram when the input member stops driving and the vehicle is pushed forward by human power. Fig. 6 is a schematic topology diagram when the input member stops driving and the vehicle is pushed backward by human power.

[0009] Hereinafter, exemplary embodiments of the present invention will be described with reference to the drawings. It should be understood that these specific descriptions are merely intended to teach those skilled in the art how to implement the present invention, and do not encompass all possible forms of the present invention or limit the scope of the present invention.

[0010] In this specification, "axial direction," "radial direction," and "circumferential direction" refer to the axial direction, radial direction, and circumferential direction of the hub T. "Fixed connection" means that two members are connected so that there is no relative movement, and unless otherwise specified, includes both a direct fixed connection and an indirect fixed connection via another member. "Power transmission connection" means that two members are connected so that torque can be transmitted, and includes both a direct connection and an indirect connection. "Lock" includes both a direct lock and an indirect lock via another member. "Engaged state" means a state in which the clutch unit can transmit torque and rotation, and "disengaged state" means a state in which the clutch unit does not transmit torque and rotation. Note that a clutch unit in an engaged state does not necessarily transmit torque and rotation.

[0011] In this specification, the term "rotational speed" may refer to the number of times (number of rotations) that a rotating object rotates around its central axis within a unit of time, and for example, the unit may be rpm (revolutions per minute).

[0012] (Vehicle) Hereinafter, a vehicle 100 according to an embodiment of the present invention will be described with reference to FIG.

[0013] As shown in FIG. 1 , the vehicle 100 of this embodiment is an electric motorcycle. Specifically, the vehicle 100 is an electric bicycle including a front wheel 1, a rear wheel 2, pedals 3, a seat 4, and a chassis. The front wheel 1 and the rear wheel 2 are mounted on the chassis. A motor (not shown) serving as a drive source is provided near the pedal 3. The motor is attached to the chassis and is located between the front wheel 1 and the rear wheel 2 in the longitudinal direction of the vehicle 100. The output of the motor is transmitted to a transmission device 200 at the rear wheel 2 via a chain 5. The vehicle 100 may have the following three drive modes. Specifically, the vehicle 100 includes the following three drive modes:

[0014] In pure electric mode, no human power is involved and the motor is driven entirely by the battery of the vehicle 100. In assisted mode, both battery drive and human power are involved in cycling. In human-powered mode, cycling is purely human-powered, with the vehicle 100 moving by pedaling 3, just like a regular bicycle.

[0015] (Transmission) Hereinafter, a transmission 200 according to one embodiment of the present invention will be described with reference to FIG.

[0016] 2, the transmission device 200 of this embodiment includes an input member 6, a hub T, and a speed change mechanism 7. The speed change mechanism 7 transmits torque from the input member 6 to the hub T. The torque output from the motor can drive the rear wheel 2 via the input member 6 and a planetary gear mechanism 20.

[0017] The vehicle 100 has a chassis fixed to the vehicle body. The chassis includes a pair of support frames 101. The hub axle O is attached to the pair of support frames 101 so as to extend along the width direction of the vehicle and is fixed non-rotatably to the support frames 101. The hub T is rotatable around the hub axle O. The hub T has an inner cylinder portion 11 provided on the radially inner side, an outer cylinder portion 12 provided on the radially outer side, and a connecting portion 13 connecting the inner cylinder portion 11 and the outer cylinder portion 12. The connecting portion 13 is plate-shaped and extends radially outward from the right end edge of the inner cylinder portion 11 to the center of the outer cylinder portion 12. The inner cylinder portion 11 extends from the radially inner edge of the connecting portion 13 toward the left in the axial direction of the hub axle O (the left-right direction in FIG. 2 ) and is attached to the hub axle O by a pair of bearings 14 arranged axially spaced apart. The outer tube portion 12 extends simultaneously from the radially outer edge of the connecting portion 13 to the left and right in the axial direction of the hub axle O, and the tire 10 of the vehicle 100 is attached to the outer peripheral surface of the outer tube portion 12.

[0018] The transmission device 200 further includes a hollow fixed shaft 8. The fixed shaft 8 is fitted onto the hub axle O and is unable to rotate relative to the hub axle O. The left end of the fixed shaft 8 extends to the vicinity of the connecting portion 13. A protrusion 81 is formed on the right end of the fixed shaft 8. The protrusion 81 has an outer shape that fits into an elongated hole formed in the support frame 101. By inserting the protrusion 81 into the elongated hole formed in the support frame 101, the fixed shaft 8 is unable to rotate relative to the support frame 101.

[0019] The input member 6 includes a sprocket 61 and a transmission sleeve 62. The transmission sleeve 62 includes an integrally formed cylindrical portion 621 and flange portion 622. The cylindrical portion 621 extends along the axial direction of the hub axle O. The input member 6 is supported by and rotatable relative to the fixed shaft 8 by being attached to the fixed shaft 8 by a pair of bearings 16 arranged on the left and right. The flange portion 622 extends radially outward from the right end of the cylindrical portion 621. A through hole into which the connecting member 63 is inserted is formed in the flange portion 622, and a stepped portion 623 is formed extending rightward from the radially inner end of the flange portion 622. The sprocket 61 has a hollow disk shape, can be attached to the stepped portion 623, and is fixed to the transmission sleeve 62 by the connecting member 63. Chain teeth are formed on the outer periphery of the sprocket 61. The chain 5 is stretched over the sprocket 61 and the sprocket on the output shaft of the motor, and meshes with the chain teeth of these sprockets. When the chain 5 is driven by the pedals 3 and / or the motor to operate, the sprocket 61 rotates accordingly.

[0020] The transmission mechanism 7 is disposed between the coupling portion 13 and the input member 6 in the axial direction of the hub axle O and includes a planetary gear mechanism 20. The planetary gear mechanism 20 is a single-row planetary gear mechanism and includes a ring gear 201, a sun gear 202, a planet carrier 203, planet gears 204, and a housing 205. The sun gear 202 serves as a power input end and is attached to the end of the cylindrical portion 621 opposite the sprocket 61, thereby achieving a power transmission connection with the input member 6 and being able to receive torque input from the motor. The housing 205 is fixed to the coupling portion 13 by a connecting member. The ring gear 201 serves as a power output end and is power transmission connected to the hub T. The planetary gears 204 are located radially between the ring gear 201 and the sun gear 202 and mesh with the ring gear 201 and the sun gear 202, respectively.

[0021] The transmission mechanism 7 further includes a first clutch unit 301, a second clutch unit 302, and a third clutch unit 70. When the first clutch unit 301 is in an engaged state, the planetary carrier 203 can be locked to the hub axle O by the first clutch unit 301 and is therefore unable to rotate. When both the second clutch unit 302 and the third clutch unit 70 are in an engaged state, the planetary carrier 203 can be locked to the ring gear 201, which serves as a power output component, by the second clutch unit 302 and the third clutch unit 70, and the planetary gear mechanism 20 rotates as a unit. The first clutch unit 301 can be selectively engaged, or the second clutch unit 302 and the third clutch unit 70 can be selectively engaged at different gear stages.

[0022] The first clutch unit 301, the second clutch unit 302, and the third clutch unit 70 are located axially of the hub axle O between the gear pair structure (ring gear 201, sun gear 202, and planet gears 204) of the planetary gear mechanism 20 and the connecting portion 13. The second clutch unit 302 is located radially outward from the first clutch unit 301. The third clutch unit 70 is located radially outward from the second clutch unit 302. The first clutch unit 301 is located radially inward from the planet carrier 203. The second clutch unit 302 and the third clutch unit 70 are located radially outward from the planet carrier 203. The first clutch unit 301, the second clutch unit 302, and the third clutch unit 70 overlap each other in the axial direction. That is, when viewed in a radial direction perpendicular to the axial direction, the first clutch unit 301, the second clutch unit 302, and the third clutch unit 70 are shielded from each other.

[0023] The first clutch unit 301 and the second clutch unit 302 each have an inner ring and an outer ring. In an engaged state, the inner ring and the outer ring cannot rotate relative to each other, and in a disengaged state, the inner ring and the outer ring can rotate relative to each other. The first clutch unit 301 and the second clutch unit 302 are both one-way clutches. In this specification, a one-way clutch refers to a clutch in which one of the inner ring and the outer ring of the clutch is connected to the input member 6 as an active component and the other of the inner ring and the outer ring is a passive component, and the one of the inner ring and the outer ring is engaged only when the input member 6 rotates in one direction, allowing the one of the inner ring and the outer ring to transmit torque to the other, and disengaged when the input member 6 changes direction and rotates in the other direction, preventing the one of the inner ring and the outer ring from transmitting torque to the other.

[0024] The first clutch unit 301 is mounted on the fixed shaft 8. Specifically, the inner ring of the first clutch unit 301 is fixed to or formed integrally with the fixed shaft 8, and the outer ring is fixed to or formed integrally with the planet carrier 203. When the first clutch unit 301 is in an engaged state, the planet carrier 203 is locked to the fixed shaft 8 by the first clutch unit 301, and can also be locked to the hub axle O. The inner ring of the second clutch unit 302 is fixed to or formed integrally with the planet carrier 203. The outer ring of the second clutch unit 302 is fixed to or formed integrally with the inner ring (inner hub) of the third clutch unit 70. When the third clutch unit 70 is in an engaged state, the ring gear 201 and the outer ring of the second clutch unit 302 are power-transmittingly connected. When the first clutch unit 301 and the second clutch unit 302 are both in an engaged state, the third clutch unit 70 is disengaged, thereby interrupting the power transmission between the sun gear 202 and the ring gear 201. In this embodiment, the third clutch unit 70 is a friction clutch.

[0025] By using the above configuration, in this embodiment, when the input member 6 rotates toward one circumferential side, one of the first clutch unit 301 and the second clutch unit 302 is engaged, and the other is disengaged. On the other hand, when the input member 6 rotates toward the other circumferential side, one of the first clutch unit 301 and the second clutch unit 302 is disengaged, and the other is engaged. Typical one-way clutches include various known one-way clutches such as a sprag-type one-way clutch, a ratchet wheel-ratchet pawl-type one-way clutch, and a roller-type one-way clutch. The third clutch unit 70 may be any known clutch, for example, a one-way clutch or a two-way clutch.

[0026] As shown in Figure 3, when the transmission 200 is in first gear, the sun gear 202 is driven toward one side in the circumferential direction by the input member 6, the second clutch unit 302 is in a disengaged state, and the first clutch unit 301 is in an engaged state. This prevents the planetary carrier 203 from rotating, and the planetary gears 204 only rotate on their axes without revolving. This causes the ring gear 201 to output a rotational speed reduced relative to the sun gear 202. The ring gear 201 is decelerated to a preset reduction ratio (gear ratio), for example, 1.23. That is, the sun gear 202, which is the power input end, rotates toward the other side in the circumferential direction at a reduction ratio where the rotational speed of the sun gear 202 is 1.23 times the rotational speed of the ring gear 201, which is the power output end.

[0027] As shown in FIG. 4 , when the transmission 200 is in second gear, the sun gear 202 is driven toward the other circumferential side by the input member 6, the first clutch unit 301 is in a disengaged state, and the second clutch unit 302 and the third clutch unit 70 are in an engaged state. As a result, the planetary carrier 203 rotates integrally with the ring gear 201, the planetary gears 204 only revolve without rotating on their axes, and the sun gear 202, planetary gears 204, planetary carrier 203, and ring gear 201 rotate integrally toward the other circumferential side. In this case, the reduction ratio (gear ratio) is 1. That is, the ring gear 201 outputs power at a constant speed relative to the sun gear 202. That is, the rotation speed of the sun gear 202, which is the power input end, is the same as the rotation speed of the ring gear 201, which is the power output end.

[0028] 5, when the driving of the input member 6 stops and the vehicle 100 is pushed forward by human power, the ring gear 201 rotates toward the other circumferential direction, the first clutch unit 301 and the second clutch unit 302 are in a disengaged state, and the third clutch unit 70 is in an engaged state. At this time, the ring gear 201 and the hub axle O are not locked. When driven by human power, the ring gear 201 drives the sun gear 202 to rotate.

[0029] 6, when the driving of the input member 6 stops and the vehicle 100 is pushed backward by human power, the ring gear 201 rotates toward one side in the circumferential direction, the first clutch unit 301 and the second clutch unit 302 are in an engaged state, and the third clutch unit 70 is in a disengaged state. At this time, the power transmission connection between the ring gear 201 and the second clutch unit 302 is released, and the ring gear 201 and the hub axle O are not locked. When driven by human power, the ring gear 201 drives the sun gear 202 to rotate.

[0030] The configuration and effects of the present embodiment will now be described.

[0031] (1) A transmission device 200 that is attached to an attachment object having a hub axle O includes an input member 6, a hub T, and a speed change mechanism 7 that transmits torque from the input member 6 to the hub T, the hub T having an inner cylindrical portion 11 provided on the radially inner side, an outer cylindrical portion 12 provided on the radially outer side, and a connecting portion 13 that connects the inner cylindrical portion 11 and the outer cylindrical portion 12, the inner cylindrical portion 11 being attached to the hub axle O, and the hub T being rotatable around the hub axle O, The input member 6 includes a sprocket 61, and the transmission mechanism 7 includes a planetary gear mechanism 20 arranged between the connecting portion 13 and the sprocket 61 in the axial direction of the hub axle O, and the planetary gear mechanism 20 has a sun gear 202, a plurality of planet gears 204, a planet carrier 203 connecting the plurality of planet gears 204, and a ring gear 201, and the sun gear 202 is transmission connected to the input member 6, and the ring gear 201 is transmission connected to the hub T.

[0032] According to this configuration, the planetary gear mechanism 20, which has the sun gear 202 as the input end and the ring gear 201 as the output end, is advantageous for the transmission mechanism 7 to achieve a large gear ratio in at least one gear, and the space near the hub T can be utilized to accommodate the transmission device 200, making the transmission device 200 smaller and more compact.

[0033] (2) The transmission mechanism 7 further includes a first clutch unit 301 and a second clutch unit 302, and when the sun gear 202 is driven by the input member 6 to rotate in one circumferential direction, the first clutch unit 301 engages to lock the planetary carrier 203 and the hub axle O, and when the sun gear 202 is driven by the input member 6 to rotate in the other circumferential direction, the second clutch unit 302 engages to rotate the planetary gear mechanism 20 integrally, and the first clutch unit 301 is arranged axially between the sun gear 202 and the connecting portion 13, and the second clutch unit 302 is arranged axially between the ring gear 201 and the connecting portion 13.

[0034] According to this configuration, two-speed drive can be realized by realizing a constant speed mode and a deceleration mode.

[0035] (3) The input member 6 further includes a transmission sleeve 62 fitted onto the hub axle O, and the sprocket 61 is fixed to the transmission sleeve 62 and is power-transmittingly connected to the sun gear 202 via the transmission sleeve 62 .

[0036] This configuration eliminates the need to specially design the sprocket 61, allowing for general-purpose components.

[0037] (4) The transmission sleeve 62 includes a cylindrical portion 621 and a flange portion 622 formed integrally, the cylindrical portion 621 extending along the axial direction, the sprocket 61 attached to the flange portion 622, and the sun gear 202 attached to the end of the cylindrical portion 621 opposite the sprocket 61.

[0038] According to this configuration, there is no need to specially design the sun gear 202, and the components can be made more versatile.

[0039] (5) The transmission device 200 further includes a hollow fixed shaft 8 that is fitted onto the hub axle O and cannot rotate relative to the hub axle O, and the first clutch unit 301 is provided on the fixed shaft 8. When the first clutch unit 301 is in an engaged state, the planetary carrier 203 is locked to the fixed shaft 8 by the first clutch unit 301.

[0040] With this configuration, there is no need to specially design the hub axle O, and the component can be made more versatile.

[0041] (6) The input member 6 is attached to the fixed shaft 8 so as to be rotatable relative to the fixed shaft 8 .

[0042] (7) The first clutch unit 301 and the second clutch unit 302 are one-way clutches, and the transmission mechanism 7 further has a third clutch unit 70, where the first clutch unit 301, the second clutch unit 302, and the third clutch unit 70 overlap each other in the axial direction, and when the first clutch unit 301 and the second clutch unit 302 are both in a connected state, the third clutch unit 70 separates to release the transmission connection between the sun gear 202 and the ring gear 201.

[0043] According to this configuration, when the vehicle 100 moves backward and the ring gear 201 of the transmission rotates in the reverse direction, the ring gear 201 can be prevented from being locked.

[0044] (8) In the radial direction of the hub axle O, the second clutch unit 302 and the third clutch unit 70 are provided radially outside the planet carrier 203, and the first clutch unit 301 is provided radially inside the planet carrier 203.

[0045] This configuration allows the transmission device to be made even smaller and more compact.

[0046] (9) When the sun gear 202 is driven by the input member 6 to rotate toward the other circumferential side, the first clutch unit 301 disengages, the second clutch unit 302 engages, the third clutch unit 70 engages, the planetary carrier 203 is locked to the ring gear 201 by the second clutch unit 302 and the third clutch unit 70, and the ring gear 201 rotates toward the other circumferential side; when the input member 6 stops driving and the ring gear 201 rotates toward one circumferential side, the first clutch unit 301 engages, the second clutch unit 302 engages, the third clutch unit 70 disengages, and the sun gear 202 rotates toward the other circumferential side.

[0047] With this configuration, two-speed drive can be easily achieved.

[0048] (10) The vehicle 100 comprises a transmission device 200, a chassis as an attachment object, front wheels 1 and rear wheels 2 provided on the chassis, and a power source attached to the chassis and positioned between the front wheels 1 and rear wheels 2 in the fore-and-aft direction of the vehicle 100, and the torque output from the power source can drive the front wheels 1 or rear wheels 2 via the input member 6 and the planetary gear mechanism 20.

[0049] According to this configuration, the space near the hub T can be utilized to accommodate the multi-speed transmission device 200, thereby realizing a smaller, more compact design and enabling the use of more versatile parts.

[0050] By using the above technical means, the input member 6 includes a sprocket 61, and the transmission mechanism 7 includes a planetary gear mechanism 20 arranged between the connecting portion 13 and the sprocket 61 in the axial direction of the hub axle O, and the planetary gear mechanism 20 has a sun gear 202, a plurality of planet gears 204, a planet carrier 203 connecting the plurality of planet gears 204, and a ring gear 201, and the sun gear 202 is transmission-connected to the input member 6, and the ring gear 201 is transmission-connected to the hub T.

[0051] According to this configuration, the space near the hub T can be utilized to accommodate the transmission device 200 including the planetary gear mechanism 20, and the transmission device 200 can be made smaller and more compact without reducing the gear ratio of the transmission device 200.

[0052] Although an embodiment of the present invention has been described above, the above embodiment merely shows one application example of the present invention, and is not intended to limit the technical scope of the present invention to the specific configuration of the above embodiment.

[0053] For example, in the above specific embodiment, the vehicle 100 is an electric two-wheeled vehicle, but the present invention is not limited thereto. In another preferred technical means, the vehicle 100 may be an electric three-wheeled vehicle, in which case the front wheels may be drive wheels and a transmission may be provided on the front wheels.

[0054] Furthermore, in the specific embodiment described above, the fixed shaft 8 is fitted onto the outside of the hub axle O, and the first clutch unit 301 and the input member 6 are mounted on the fixed shaft 8, but this is not limiting. In another preferred technical means, the first clutch unit 301 and the input member 6 may be mounted directly on the hub axle O without providing a fixed shaft 8.

[0055] In the specific embodiment described above, the reduction ratio is 1.23 in the first gear stage. However, it goes without saying that the reduction ratio can be adjusted by setting a different gear ratio.

[0056] REFERENCE SIGNS LIST 100 Vehicle 1 Front wheel 2 Rear wheel 3 Pedal 4 Seat 5 Chain 10 Tire 101 Support frame 200 Transmission device T Hub 11 Inner cylindrical portion 12 Outer cylindrical portion 13 Connecting portion 14 Bearing 16 Bearing O Hub shaft 6 Input member 61 Sprocket 62 Transmission sleeve 621 Cylindrical portion 622 Flange portion 623 Step portion 63 Connecting member 7 Transmission mechanism 20 Planetary gear mechanism 201 Ring gear 202 Sun gear 203 Planet carrier 204 Planetary gear 205 Housing 301 First clutch unit 302 Second clutch unit 70 Third clutch unit 8 Fixed shaft 81 Protrusion

Claims

1. A transmission device that is attached to an attachment object having a hub axle (O), comprising: an input member (6); a hub (T); and a speed change mechanism (7) that transmits torque from the input member (6) to the hub (T), wherein the hub (T) has an inner cylindrical portion (11) provided on the radially inner side, an outer cylindrical portion (12) provided on the radially outer side, and a connecting portion (13) that connects the inner cylindrical portion (11) and the outer cylindrical portion (12), wherein the inner cylindrical portion (11) is attached to the hub axle (O), and the hub (T) is rotatable around the hub axle (O), the input member (6) includes a sprocket (61), and the speed change mechanism (7) is disposed between the connecting portion (13) and the sprocket (61) in the axial direction of the hub axle (O) and includes a planetary gear mechanism (20), and the planetary gear mechanism (20) is A transmission device comprising: a sun gear (202); a plurality of planet gears (204); a planet carrier (203) connecting the plurality of planet gears (204); and a ring gear (201), wherein the sun gear (202) is transmission-connected to the input member (6), and the ring gear (201) is transmission-connected to the hub (T).

2. A transmission device according to claim 1, wherein the speed change mechanism (7) further includes a first clutch unit (301) and a second clutch unit (302), and when the sun gear (202) is driven by the input member (6) to rotate in one circumferential direction, the first clutch unit (301) is engaged to lock the planet carrier (203) and the hub axle (O), and when the sun gear (202) is driven by the input member (6) to rotate in the other circumferential direction, the second clutch unit (302) is engaged to rotate the planetary gear mechanism (20) integrally, the first clutch unit (301) is disposed between the sun gear (202) and the connecting portion (13) in the axial direction, and the second clutch unit (302) is disposed between the ring gear (201) and the connecting portion (13) in the axial direction.

3. A transmission device according to claim 1 or 2, wherein the input member (6) further includes a transmission sleeve (62) fitted onto the hub axle (O), and the sprocket (61) is fixed to the transmission sleeve (62) and is connected to the sun gear (202) via the transmission sleeve (62).

4. A transmission device according to claim 3, wherein the transmission sleeve (62) includes an integrally formed cylindrical portion (621) and flange portion (622), the cylindrical portion (621) extends along the axial direction, the sprocket (61) is attached to the flange portion (622), and the sun gear (202) is attached to the end of the cylindrical portion (621) opposite to the sprocket (61).

5. A transmission device according to claim 2, wherein the transmission device (200) further includes a hollow fixed shaft (8) fitted onto the hub axle (O) and unable to rotate relative to the hub axle (O), the first clutch unit (301) is provided on the fixed shaft (8), and when the first clutch unit (301) is in an engaged state, the planet carrier (203) is locked to the fixed shaft (8) by the first clutch unit (301).

6. A transmission device according to claim 5, wherein the input member (6) is attached to the fixed shaft (8) so as to be rotatable relative to the fixed shaft (8).

7. A transmission device according to claim 2, wherein the first clutch unit (301) and the second clutch unit (302) are one-way clutches, the speed change mechanism (7) further has a third clutch unit (70), the first clutch unit (301), the second clutch unit (302) and the third clutch unit (70) overlap one another in the axial direction, and when the first clutch unit (301) and the second clutch unit (302) are both in an engaged state, the third clutch unit (70) separates to release the transmission connection between the sun gear (202) and the ring gear (201).

8. A transmission device according to claim 7, wherein the second clutch unit (302) and the third clutch unit (70) are provided radially outside the planet carrier (203) in the radial direction of the hub axle (O), and the first clutch unit (301) is provided radially inside the planet carrier (203).

9. A transmission device as set forth in claim 7, wherein, when the sun gear (202) is driven by the input member (6) to rotate toward the other circumferential side, the first clutch unit (301) is disengaged, the second clutch unit (302) is engaged, the third clutch unit (70) is engaged, the planetary carrier (203) is locked to the ring gear (201) by the second clutch unit (302) and the third clutch unit (70), and the ring gear (201) rotates toward the other circumferential side; and when the input member (6) stops driving and the ring gear (201) rotates toward one circumferential side, the first clutch unit (301) is engaged, the second clutch unit (302) is engaged, the third clutch unit (70) is disengaged, and the sun gear (202) rotates toward the other circumferential side.

10. A vehicle comprising: a transmission device (200) according to any one of claims 1 to 9; a chassis as the mounting object; front wheels (1) and rear wheels (2) provided on the chassis; and a power source attached to the chassis and positioned between the front wheels (1) and the rear wheels (2) in the fore-and-aft direction of the vehicle (100), wherein the torque output from the power source can drive the front wheels (1) or the rear wheels (2) via the input member (6) and the planetary gear mechanism (20).

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