Power transmission device and automobile including the same

Abstract

A power transmission apparatus includes a motor to drive a rotating shaft, a first speed reducer to receive a torque from the rotating shaft, a second speed reducer to receive a torque from the first speed reducer, and a first clutch provided outside the second speed reducer to connect and disconnect the second speed reducer with an external component.

Description

[0001] Cross-citation of related applications

[0002] This application claims priority and benefit to Korean Patent Application No. 10-2021-0055514, filed with the Korean Intellectual Property Office on April 29, 2021, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present invention relates to a power transmission device and an automobile including the power transmission device, and more specifically, to a power transmission device capable of variable deceleration and an automobile including the power transmission device. Background Technology

[0004] In electric vehicles equipped with a speed reducer, the speed reducer reduces the rotational speed of the motor and transmits the reduced rotational speed to the wheels. Generally, a planetary gear reducer is provided, which has a structure in which a sun gear, planet gears, ring gears and a support are coupled to each other.

[0005] It may be necessary to install planetary gears with multiple different reduction ratios in a vehicle to achieve optimal efficiency depending on the vehicle's driving conditions. However, the structure of the reducer becomes complex to provide multiple reduction ratios. Therefore, this structural complexity not only increases the reducer's size but also degrades its durability. Thus, to manufacture a reducer that provides multiple reduction ratios, the reducer's construction needs to be simplified, and its durability also needs to be increased. Summary of the Invention

[0006] This summary is provided to introduce selected concepts in a simplified form, which will be further described in the following detailed description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to help determine the scope of the claimed subject matter.

[0007] In one general aspect, a power transmission device includes: an electric motor configured to drive a rotating shaft; a first reducer configured to receive torque from the rotating shaft; a second reducer configured to receive torque from the first reducer; and a first clutch disposed outside the second reducer and configured to connect the second reducer to an external component and disconnect the second reducer from the external component.

[0008] The first reducer may include: a first sun gear configured to receive power from a rotating shaft; and a first planetary gear disposed outside the first sun gear and engaging with the first sun gear.

[0009] The second reduction gear can include a second sun gear, and a second planetary gear disposed outside the second sun gear and engaged with the second sun gear, and the second planetary gear is configured to rotate together with the first planetary gear.

[0010] The second reduction gear can include a ring gear disposed outside the second planetary gear and engaged with the second planetary gear.

[0011] The first clutch can be disposed outside the ring gear and configured to connect and disconnect the ring gear with an external component.

[0012] The power transmission device can further include a second clutch disposed outside the second reduction gear and configured to connect and disconnect the second reduction gear with an external component, and the second clutch can be disposed outside the second sun gear and configured to connect and disconnect the second sun gear with an external component.

[0013] The power transmission device can include a support coupled to the first reduction gear and the second reduction gear and configured to transmit a torque of the first reduction gear to the second reduction gear.

[0014] The power transmission device can further include a differential gear connected to the gear shaft.

[0015] The rotation shaft can be connected to a center of the first sun gear.

[0016] The rotation shaft can be spaced apart from the center of the first sun gear in a radial direction (R) of the first sun gear.

[0017] The power transmission device can further include a first rotation gear connected to the support and configured to rotate together with the support, and a second rotation gear disposed between the first rotation gear and the differential gear and engaged with the first rotation gear.

[0018] The power transmission device can further include a third rotation gear connected to the rotation shaft and configured to rotate together with the rotation shaft, and the third rotation gear can be disposed outside the first sun gear and engaged with the first sun gear.

[0019] In another general aspect, an automobile includes: a first wheel and a second wheel, the first wheel disposed at a left side of the automobile and the second wheel disposed at a right side of the automobile; and a power transmission device configured to provide torque to the first wheel and the second wheel. The power transmission device includes: an electric motor configured to drive a rotation shaft; a first speed reducer configured to receive torque from the rotation shaft; a second speed reducer configured to receive torque from the first speed reducer; a bracket coupled to the first speed reducer and the second speed reducer; and a first clutch disposed outside the second speed reducer and configured to connect and disconnect the second speed reducer with an external component.

[0020] The power transmission device can further include a differential gear connected to the bracket, the first speed reducer can include: a first sun gear configured to receive power from the rotation shaft; and a first planetary gear disposed outside the first sun gear and engaged with the first sun gear, and the second speed reducer can include: a second sun gear; and a second planetary gear disposed outside the second sun gear and engaged with the second sun gear, and the second planetary gear is configured to rotate together with the first planetary gear.

[0021] The differential gear can include: a first inner gear connected to a first wheel shaft connected with the first wheel and configured to rotate together with the first wheel; a second inner gear connected to a second wheel shaft connected with the second wheel and configured to rotate together with the second wheel; and an outer gear disposed outside the first inner gear and the second inner gear and engaged with the first inner gear and the second inner gear, and the outer gear can be connected to the bracket and configured to rotate together with the bracket.

[0022] The first inner gear can include: an inner gear connected to the first wheel; and an outer gear disposed between the inner gear and the outer gear and engaged with the inner gear and the outer gear.

[0023] The rotation shaft can be spaced apart from the first wheel shaft connected to the first wheel and the second wheel shaft connected to the second wheel in a radial direction (R) of the first sun gear.

[0024] The first sun gear can be spaced apart from the first wheel shaft and the second wheel shaft in a radial direction (R) of the first sun gear.

[0025] A center of the first sun gear can be spaced apart from the first wheel shaft and the second wheel shaft in a radial direction (R) of the first sun gear.

[0026] The first wheel shaft and the second wheel shaft can pass through the center of the first sun gear.

[0027] Other features and aspects will be apparent from the following detailed description, the drawings and the claims. Attached Figure Description

[0028] The accompanying drawings provide a further understanding of the invention and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

[0029] Figure 1 This is a view showing the structure of a power transmission device according to a first exemplary embodiment of the present disclosure.

[0030] Figure 2 This is a view showing the structure of a power transmission device according to a second exemplary embodiment of the present disclosure.

[0031] Figure 3 This is a view showing the structure of a power transmission device according to a third exemplary embodiment of the present disclosure.

[0032] Figure 4 This is a view showing the structure of a power transmission device according to a fourth exemplary embodiment of the present disclosure. Detailed Implementation

[0033] In the following description, a power transmission device according to the present disclosure and a vehicle including the power transmission device will be described with reference to the accompanying drawings.

[0034] Power transmission device

[0035] Figure 1 This is a view showing the structure of a power transmission device according to a first exemplary embodiment of the present disclosure, and Figure 2 This is a view showing the structure of a power transmission device according to a second exemplary embodiment of the present disclosure. Furthermore, Figure 3 This is a view showing the structure of a power transmission device according to a third exemplary embodiment of the present disclosure, and Figure 4 This is a view showing the structure of a power transmission device according to a fourth exemplary embodiment of the present disclosure.

[0036] like Figures 1 to 4 As shown, the power transmission device 10 according to this disclosure may include a motor 100 that generates power to drive a rotating shaft 110. Figures 1 to 4 As shown, the motor 100 can be located outside the wheels 20 and 30, but on the other hand, the motor 100 can be located inside the wheels 20 and 30. Meanwhile, according to this disclosure, the rotating shaft 110 driven by the motor 100 can have a linear shape.

[0037] In addition, the power transmission device 10 may include: a first reducer 200 that receives torque from the rotating shaft 110; a second reducer 300 that receives torque from the first reducer 200; and a bracket 400 coupled to the first reducer 200 and the second reducer 300.

[0038] More specifically, the first reducer 200 may include: a first sun gear 210 that receives power from the rotating shaft 110; and a first planetary gear 220 disposed on the outer side of the first sun gear 210 and engaging with the first sun gear 210. That is, the first planetary gear 220 can revolve around the outer side of the first sun gear 210. Therefore, according to this disclosure, when power is transmitted from the first sun gear 210 to the first planetary gear 220, the rotational speed can be reduced.

[0039] Furthermore, the second reducer 300 may include: a second sun gear 310; a second planetary gear 320 disposed on the outside of and engaging with the second sun gear 310, and rotating together with the first planetary gear 220; and a ring gear 330 disposed on the outside of and engaging with the second planetary gear 320. More specifically, the second planetary gear 320 is directly connected to the first planetary gear 220, and therefore the first planetary gear 220 and the second planetary gear 320 can be fixed to each other. Furthermore, the second planetary gear 320 can revolve around the outside of the second sun gear 310. The second planetary gear 320 can rotate inside the ring gear 330, and simultaneously, the second planetary gear can also revolve inside the ring gear. Meanwhile, as... Figure 1 As shown in the present disclosure, the outer diameter of the second sun gear 310 may be larger than the outer diameter of the first sun gear 210, and the outer diameter of the first planetary gear 220 may be larger than the outer diameter of the second planetary gear 320. However, the relationship between the aforementioned outer diameters is not limited thereto.

[0040] As described above, according to this disclosure, the first planetary gear 220 and the second planetary gear 320 can be fixed to each other. Therefore, the rotational motion between the first planetary gear 220 and the second planetary gear 320 can be synchronized. That is, according to this disclosure, when the first planetary gear 220 rotates, the second planetary gear 320 can rotate at the same angular velocity as the first planetary gear 220. Conversely, when the second planetary gear 320 rotates, the first planetary gear 220 can rotate at the same angular velocity as the second planetary gear 320.

[0041] Continue to refer to Figures 1 to 4The power transmission device 10 according to the present disclosure can further include a first clutch 500 and a second clutch 600, which are disposed outside the second reducer 300. The first clutch 500 and the second clutch 600 can be components for connecting the second reducer 300 with external components of the power transmission device, or can be components for disconnecting the second reducer from external components of the power transmission device. For example, when the power transmission device 10 according to the present disclosure is installed to an automobile, the first clutch 500 and the second clutch 600 can be components for selectively fixing some portions of the second reducer 300 with other components of the automobile, or components for selectively disconnecting some portions of the second reducer from other components of the automobile.

[0042] More specifically, as shown in Figures 1 to 4 , the first clutch 500 can be disposed outside the ring gear 330 and can connect or disconnect the ring gear 330 with external components of the power transmission device. Also, the second clutch 600 can be disposed outside the second sun gear 310 and can connect or disconnect the second sun gear 310 with external components of the power transmission device. The description of the structure and the principle of operation of the first clutch 500 and the second clutch 600 will be replaced by the description of the clutch according to the related art.

[0043] Continuing to refer to Figures 1 to 4 , the power transmission device 10 according to the present disclosure can further include a differential gear 700 connected to the bracket 400. For example, when the automobile turns, there is a difference in the rotational speed between the left wheel and the right wheel of the automobile, and the differential gear 700 can be a component that utilizes torque to make the left wheel and the right wheel have different rotational speeds. The configuration of the differential gear 700 will be described below.

[0044] Meanwhile, as shown in Figures 1 to 3 , according to the first to third exemplary embodiments of the present disclosure, the rotational shaft 110 of the motor 100 can be connected to the center of the first sun gear 210. More preferably, the rotational shaft 110 can be directly connected to the first sun gear 210. For example, the rotational shaft 110 can pass through the center of the first sun gear 210.

[0045] On the other hand, as shown in Figure 4 , according to the fourth exemplary embodiment of the present disclosure, the rotational shaft 110 of the motor 100 can be spaced apart from the first sun gear 210 in the radial direction R of the first sun gear 210. Accordingly, according to the fourth exemplary embodiment, such a component that serves as a medium for power transmission between the first sun gear 210 and the rotational shaft 110 can be additionally provided between the first sun gear 210 and the rotational shaft 110.

[0046] Meanwhile, as shown in Figure 3 According to a third exemplary embodiment of the present disclosure, the power transmission device 10 can further include a first rotary gear 810 connected to the bracket 400 and rotatable together with the bracket 400, and a second rotary gear 820 disposed between the first rotary gear 810 and the differential gear 700 and engaged with the first rotary gear 810 and the differential gear 700.

[0047] As shown in Figure 3 Unlike the first and second exemplary embodiments of the present disclosure, the power transmission device 10 according to the third exemplary embodiment can have a bias structure in which the first reducer 200, the second reducer 300, and the bracket 400 are spaced apart from the differential gear 700. Accordingly, the first rotary gear 810 and the second rotary gear 820 can be components that serve as a medium for power transmission between the bracket 400 and the differential gear 700.

[0048] Meanwhile, as shown in Figure 4 According to a fourth exemplary embodiment of the present disclosure, the power transmission device 10 can further include a third rotary gear 830 connected to the rotary shaft 110 and rotatable together with the rotary shaft 110. Here, the third rotary gear 830 can be disposed on the outside of the first sun gear 210 and engaged with the first sun gear 210. The third rotary gear 830 can be a component that serves as a medium for power transmission between the motor 100 and the first sun gear 210.

[0049] As shown in Figure 4 Unlike the first to third exemplary embodiments of the present disclosure, the power transmission device 10 according to the fourth exemplary embodiment of the present disclosure can have a structure in which the rotary shaft 110 is spaced apart from the first sun gear 210. Accordingly, the third rotary gear 830 can be a component that serves as a medium for power transmission between the rotary shaft 110 and the first sun gear 210.

[0050] Automobile

[0051] Referring to Figures 1 to 4 According to the present disclosure, an automobile can include first and second wheels 20 and 30 disposed on one side and the other side, respectively, in a left-right direction, and a power transmission device 10 for providing torque to the first and second wheels 20 and 30.

[0052] The power transmission device 10 can include a motor 100 to drive a rotation shaft 110, a first reducer 200 to receive torque from the rotation shaft 110, a second reducer 300 to receive torque from the first reducer 200, a bracket 400 coupled to the first reducer 200 and the second reducer 300, a first clutch 500 disposed outside the second reducer 300 and connecting or disconnecting the second reducer 300 and an external component of the power transmission device 10, and a second clutch 600 disposed outside the second reducer 300 and connecting or disconnecting the second reducer 300 and an external component of the power transmission device 10.

[0053] Further, the power transmission device 10 provided in the automobile can further include a differential gear 700 connected to the bracket 400. Further, the first reducer 200 can include a first sun gear 210 to receive power from the rotation shaft 110, and a first planetary gear 220 disposed on an outer side of the first sun gear 210 and engaged with the first sun gear 210. Further, the second reducer 300 can include a second sun gear 310, and a second planetary gear 320 disposed on an outer side of the second sun gear 310 and engaged with the second sun gear 310. The second planetary gear 320 is connected to the first planetary gear 220 and revolves together with the first planetary gear 220.

[0054] Meanwhile, as described above, the first clutch 500 can be disposed outside the ring gear 330 in the second reducer 300, and the first clutch can connect or disconnect the ring gear 330 and an external component of the power transmission device. Further, as described above, the second clutch 600 can be disposed outside the second sun gear 310 in the second reducer 300, and the second clutch can connect or disconnect the second sun gear 310 and an external component of the power transmission device.

[0055] Meanwhile, as Figure 2 shown in FIG. 2, according to a second exemplary embodiment of the present disclosure, the differential gear 700 can include a first inner gear 710 connected to the first wheel shaft 40 connected to the first wheel 20 and rotatable together with the first wheel 20, a second inner gear 720 connected to the second wheel shaft 50 connected to the second wheel 30 and rotatable together with the second wheel 30, and an outer gear 730 disposed on an outer side of the first inner gear 710 and the second inner gear 720 and engaged with the first inner gear 710 and the second inner gear 720. Here, as Figure 2 shown in FIG. 2, the outer gear 730 can be connected to the bracket 400 and rotate together with the bracket 400.

[0056] Meanwhile, according to a second exemplary embodiment of the present disclosure, the first internal gear 710 and the second internal gear 720 provided in the differential gear 700 can have different structures. For example, as shown in Figure 2 the first internal gear 710 can include an internal gear 712 connected to the first wheel shaft 40 by the first wheel 20, and an external gear 714 provided between and engaged with the internal gear 712 and the external gear 730. On the other hand, the second internal gear 720 can have a single gear structure.

[0057] As described above, according to the second exemplary embodiment of the present disclosure, a differential gear having a planetary gear structure can be provided in an automobile. In this case, the volume of the automobile or the power transmission device can be reduced in the axial direction.

[0058] Meanwhile, referring to Figure 3 and Figure 4 , according to the third and fourth exemplary embodiments of the present disclosure, the rotational shaft 110 of the motor 100 in the automobile can be spaced apart from the first wheel shaft 40 connected to the first wheel 20 and the second wheel shaft 50 connected to the second wheel 30 in the radial direction R of the first sun gear 210.

[0059] Here, as shown in Figure 3 , according to the third exemplary embodiment of the present disclosure, the first sun gear 210 can be spaced apart from the first wheel shaft 40 and the second wheel shaft 50 in the radial direction R.

[0060] On the other hand, as shown in Figure 4 , according to the fourth exemplary embodiment of the present disclosure, the center of the first sun gear 210 can be aligned with the first wheel shaft 40 and the second wheel shaft 50 in the radial direction R. For example, referring to Figure 4 , the first wheel shaft 40 and the second wheel shaft 50 can pass through the center of the first sun gear 210.

[0061] A driving method of the power transmission device 10 and the automobile according to the present disclosure will be described hereinafter based on the foregoing description.

[0062] In the power transmission device and the automobile according to the present disclosure, two types of reduction modes can be obtained.

[0063] First, in the first reduction mode by the power transmission device 10, the ring gear 330 is engaged with the external components of the power transmission device by the first clutch 500, but the second sun gear 310 is disconnected from the external components of the power transmission device by the second clutch 600. Accordingly, the torque of the rotational shaft 110 generated according to the driving of the motor 100 is transmitted to the carrier 400 through the first sun gear 210, the first planetary gear 220, the second planetary gear 320, and the ring gear 330. Here, the carrier 400 rotates at a rotational angular velocity reduced by the first reduction ratio compared to the rotational angular velocity of the rotational shaft 110. Meanwhile, the carrier 400, which has received the power, transmits the power to the differential gear 700. The first wheel 20 and the second wheel 30 receive the power from the differential gear 700 through the first wheel shaft 40 and the second wheel shaft 50, and then rotate. Meanwhile, in the first reduction mode, the second sun gear 310 rotates by being engaged with the rotation of the second planetary gear 320.

[0064] Second, in the second reduction mode by the power transmission device 10, the second sun gear 310 is engaged with the external components of the power transmission device by the second clutch 600, but the ring gear 330 is disconnected from the external components of the power transmission device by the first clutch 500. Accordingly, the torque of the rotational shaft 110 generated according to the driving of the motor 100 is transmitted to the carrier 400 through the first sun gear 210, the first planetary gear 220, the second planetary gear 320, and the second sun gear 310. Here, the carrier 400 rotates at a rotational angular velocity reduced by the second reduction ratio compared to the rotational angular velocity of the rotational shaft 110. Meanwhile, the carrier 400, which has received the power, transmits the power to the differential gear 700. The first wheel 20 and the second wheel 30 receive the power from the differential gear 700 through the first wheel shaft 40 and the second wheel shaft 50, and then rotate. Meanwhile, in the second reduction mode, the ring gear 330 rotates by being engaged with the rotation of the second planetary gear 320.

[0065] Meanwhile, the second sun gear 310 is engaged with the external components of the power transmission device by the second clutch 600, and the ring gear 330 is engaged with the external components of the power transmission device by the first clutch 500. In this case, a parked state can be obtained. On the other hand, the second sun gear 310 is disconnected from the external components of the power transmission device by the second clutch 600, and the ring gear 330 is disconnected from the external components of the power transmission device by the first clutch 500. In this case, it is possible to prevent the power from being transmitted to the carrier 400 during driving.

[0066] Meanwhile, Z S1 is the number of teeth on the first sun gear 210, Z S2 is the number of teeth on the second sun gear 310, ZP1 is the number of teeth on the first planetary gear 220, Z P2 is the number of teeth on the second planetary gear 320, Z R is the number of teeth on the ring gear 330, the first reduction ratio R1 and the second reduction ratio R2 of the power transmission device 10 according to an exemplary embodiment of the present disclosure can be expressed as follows:

[0067] R1 = (Z P1 / Z S1 ) x (Z R / Z P2 ) + 1

[0068] R2 = (Z P1 / Z S1 ) x (Z S2 / Z P2 ) + 1

[0069] Meanwhile, the above-described contents regarding the power transmission device 10 according to the present disclosure can also be applied to an automobile according to the present disclosure in the same manner.

[0070] According to the present disclosure, a reducer for an automobile can be manufactured, which, although having a simplified structure compared to the prior art, is capable of providing a plurality of reduction ratios, and also has increased durability.

[0071] The present disclosure has been described with reference to specific embodiments and drawings, but the present disclosure is not limited thereto, and it is obvious that the present disclosure can be variously changed and modified within the technical spirit of the present disclosure and the equivalent scope of the appended claims by those skilled in the art to which the present disclosure pertains.

Claims

1. A power transmission device, comprising: The motor is configured to drive the rotating shaft; A first reducer is configured to receive torque from the rotating shaft; The second reducer is configured to receive torque from the first reducer; as well as A first clutch is disposed outside the second reducer and configured to connect the second reducer to an external component and to disconnect the second reducer from the external component; The first reducer includes: A first sun gear, configured to receive power from the rotating shaft; and A first planetary gear is disposed outside the first sun gear and engages with the first sun gear; The second reducer includes: The second sun gear; and A second planetary gear is disposed outside the second sun gear and engages with the second sun gear, and the second planetary gear is configured to rotate together with the first planetary gear; The power transmission device further includes a second clutch, which is disposed outside the second reducer and configured to connect the second reducer to an external component and to disconnect the second reducer from the external component. The second clutch is disposed outside the second sun gear and configured to connect the second sun gear to an external component and to disconnect the second sun gear from the external component.

2. The power transmission device according to claim 1, wherein, The second reducer includes a ring gear disposed outside the second planetary gear and engaging with the second planetary gear.

3. The power transmission device according to claim 2, wherein, The first clutch is disposed outside the ring gear and configured to connect the ring gear to an external component and to disconnect the ring gear from the external component.

4. The power transmission device according to claim 1 further includes a bracket, the bracket being coupled to the first reducer and the second reducer and configured to transmit the torque of the first reducer to the second reducer.

5. The power transmission device according to claim 4 further includes a differential gear, the differential gear being connected to the bracket.

6. The power transmission device according to claim 5, wherein, The rotating shaft is connected to the center of the first sun gear.

7. The power transmission device according to claim 5, wherein, The rotation axis is spaced apart from the center of the first sun gear in the radial direction (R).

8. The power transmission device according to claim 6, further comprising: A first rotating gear is connected to the bracket and configured to rotate together with the bracket; as well as A second rotating gear is disposed between the first rotating gear and the differential gear, and the second rotating gear engages with the first rotating gear.

9. The power transmission device according to claim 7, further comprising a third rotating gear connected to the rotating shaft and configured to rotate together with the rotating shaft. in, The third rotary gear is disposed on the outside of the first sun gear and engages with the first sun gear.

10. A car comprising: A first wheel and a second wheel, wherein the first wheel is located on the left side of the vehicle and the second wheel is located on the right side of the vehicle; as well as A power transmission device configured to provide torque to the first wheel and the second wheel, wherein the power transmission device includes: The motor is configured to drive the rotating shaft; A first reducer is configured to receive torque from the rotating shaft; The second reducer is configured to receive torque from the first reducer; The bracket is coupled to the first reducer and the second reducer; and A first clutch is disposed outside the second reducer and configured to connect the second reducer to an external component and to disconnect the second reducer from the external component; The first reducer includes: A first sun gear, configured to receive power from the rotating shaft; and A first planetary gear is disposed outside the first sun gear and engages with the first sun gear; The second reducer includes: The second sun gear; and A second planetary gear is disposed outside the second sun gear and engages with the second sun gear, and the second planetary gear is configured to rotate together with the first planetary gear; The power transmission device further includes a second clutch, which is disposed outside the second reducer and configured to connect the second reducer to an external component and to disconnect the second reducer from the external component. The second clutch is disposed outside the second sun gear and configured to connect the second sun gear to an external component and to disconnect the second sun gear from the external component.

11. The automobile according to claim 10, wherein, The power transmission device also includes a differential gear, which is connected to the bracket.

12. The automobile according to claim 11, wherein, The differential gear includes: A first internal gear is connected to a first wheel axle connected to the first wheel and configured to rotate together with the first wheel; A second internal gear, connected to a second wheel axle connected to the second wheel and configured to rotate together with the second wheel; and An external gear is disposed outside and engages with the first internal gear and the second internal gear. The external gear is connected to the bracket and configured to rotate together with the bracket.

13. The automobile according to claim 12, wherein, The first internal gear includes: Internal gear, connected to the first wheel; and An external gear is disposed between the internal gear and the external gear and engages with the internal gear and the external gear.

14. The automobile according to claim 10, wherein, The rotating shaft is spaced apart from the first wheel axle connected to the first wheel and the second wheel axle connected to the second wheel in the radial direction (R) of the first sun gear.

15. The automobile according to claim 14, wherein, The first sun gear is spaced apart from the first wheel axle and the second wheel axle in the radial direction (R) of the first sun gear.

16. The automobile according to claim 14, wherein, The center of the first sun gear is spaced apart from the first wheel axle and the second wheel axle in the radial direction (R) of the first sun gear.

17. The automobile according to claim 14, wherein, The first wheel axle and the second wheel axle pass through the center of the first sun gear.

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