Power transmission device

Abstract

To provide a power transmission device for enabling the rotation of right and left driving wheels in both the same direction and opposite directions to make a vehicle travel without using a plurality of power sources corresponding to the respective driving wheels.SOLUTION: A power transmission device 20A includes a gear unit 22 forming a first transmission passage for transmitting power from an engine (a power source) so that right and left rear wheels (a first driving wheel and a second driving wheel) are rotated in the same direction and a second transmission passage for transmitting the power from the engine so that the right and left rear wheels are rotated in the opposite directions, and a connection device 24 for switching between connection of the right and left rear wheels to the first transmission passage and connection of the right and left rear wheels to the second transmission passage.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a power transmission device mounted on a vehicle. [Background technology]

[0002] Conventionally, there are known techniques for transmitting power to each drive wheel of a vehicle. For example, Patent Document 1 describes a left and right independent drive vehicle in which an electric motor is mounted corresponding to each of the two front left and right wheels and an electric motor is mounted corresponding to each of the two rear left and right wheels. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-67076 A Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, in a vehicle in which electric motors are provided as power sources corresponding to each drive wheel as described in the above Patent Document 1, the left and right drive wheels can be rotated in opposite directions to turn with a turning radius smaller than the minimum turning radius of the vehicle. For example, if the left and right rear wheels as drive wheels are rotated in opposite directions, the vehicle can be turned while turning with the front wheel side as the turning center and change direction. However, multiple power sources corresponding to each drive wheel are required, which leads to an increase in the number of parts and a complicated structure. In particular, in a vehicle powered by an internal combustion engine, it is difficult to transmit power in different directions to each drive wheel.

[0005] The present invention has been made in consideration of these problems, and its object is to provide a power transmission device that can rotate the left and right drive wheels in both the same direction and opposite directions to run a vehicle without using multiple power sources corresponding to each drive wheel. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, the power transmission device of the present invention is a power transmission device mounted on a vehicle and transmits power from a power source to a first drive wheel and a second drive wheel on left and right sides, and includes a gear device that forms a first transmission path that transmits the power from the power source so that the first drive wheel and the second drive wheel rotate in the same direction, and a second transmission path that transmits the power from the power source so that the first drive wheel and the second drive wheel rotate in the opposite direction, and a connection device that switches between a connection between the first drive wheel and the second drive wheel and the first transmission path and a connection between the first drive wheel and the second drive wheel and the second transmission path.

[0007] With this configuration, when the first transmission path formed by the gear device is selected by the connection device, the first drive wheel and the second drive wheel are rotated in the same direction, and the vehicle can travel normally, such as going straight or turning. On the other hand, when the second transmission path formed by the gear device is selected by the connection device, the first drive wheel and the second drive wheel are rotated in the opposite direction, and the vehicle can change direction. Therefore, according to the power transmission device of the present invention, it is possible to rotate the left and right drive wheels in both the same direction and opposite directions to run the vehicle, without using multiple power sources corresponding to each drive wheel.

[0008] It is also preferable that the gear device comprises a differential device which receives power from the power source and outputs the input power to a first output member connected to the first drive wheel and a second output member, and a planetary gear mechanism including a fixed element, a first rotating element connected to the second output member, and a second rotating element which rotates in the opposite direction to the first rotating element when power is transmitted from the second output member to the first rotating element, and the connection device comprises a first connection device which connects and disconnects the second drive wheel and the first rotating element, and a second connection device which connects and disconnects the second drive wheel and the second rotating element.

[0009] With this configuration, the first drive wheel rotates in the same direction as the first output member of the differential device. When the second drive wheel and the first rotating element of the planetary gear mechanism, which rotates in the same direction as the first output member and the second output member, are connected by the first connecting device, the first transmission path is formed, and the first drive wheel and the second drive wheel rotate in the same direction. On the other hand, when the second drive wheel and the second rotating element of the planetary gear mechanism are connected by the second connecting device, the second transmission path is formed, and the first drive wheel and the second drive wheel rotate in the opposite direction. Therefore, a configuration in which the left and right drive wheels rotate in both the same direction and the opposite direction can be realized by simply adding the planetary gear mechanism, the first connecting device, and the second connecting device to the differential device to which power is input from the power source, and the complexity of the structure of the power transmission device can be suppressed.

[0010] Furthermore, it is preferable that the planetary gear mechanism includes a ring gear as the fixed element, a sun gear as the second rotating element, a plurality of first pinion gears meshing with the sun gear, a plurality of second pinion gears meshing with the ring gear and the plurality of first pinion gears, and a carrier as the first rotating element that rotatably holds the plurality of first pinion gears and the plurality of second pinion gears and revolves together with the plurality of first pinion gears and the plurality of second pinion gears. With this configuration, it is possible to realize a configuration in which the left and right drive wheels are rotated in both the same direction and in opposite directions using a double pinion type planetary gear mechanism, and it is possible to prevent the structure of the power transmission device from becoming complicated.

[0011] In addition, it is preferable that the differential is a bevel gear type differential including a first side gear as the first output member and a second side gear as the second output member. With this configuration, a configuration can be realized in which the left and right drive wheels are rotated in both the same direction and in opposite directions using the bevel gear type differential, and it is possible to suppress the complexity of the structure of the power transmission device.

[0012] Moreover, it is preferable that the differential device includes a differential side ring gear to which power from the power source is input, a differential side sun gear as the first output member, a plurality of differential side first pinion gears meshing with the differential side sun gear, a plurality of differential side second pinion gears meshing with the differential side ring gear and the plurality of differential side first pinion gears, and a differential side carrier as the second output member that holds the plurality of differential side first pinion gears and the plurality of differential side second pinion gears so as to be rotatable and revolves together with the plurality of differential side first pinion gears and the plurality of differential side second pinion gears. With this configuration, it is possible to realize a configuration in which the left and right drive wheels are rotated in both the same direction and in opposite directions using a planetary gear mechanism type differential device, and it is possible to suppress the complexity of the structure of the power transmission device.

[0013] In addition, it is preferable that the differential device, the planetary gear mechanism, the first connecting device and the second connecting device are disposed on a drive shaft. With this configuration, it is possible to prevent the power transmission device from becoming large in diameter. Effect of the Invention

[0014] According to the power transmission device of the present invention, it is possible to run a vehicle by rotating the left and right drive wheels both in the same direction and in opposite directions without using multiple power sources corresponding to each drive wheel. [Brief description of the drawings]

[0015] [Figure 1] 1 is a schematic configuration diagram showing a vehicle equipped with a power transmission device of a first embodiment. [Diagram 2] 1 is a schematic configuration diagram showing a power transmission device of a first embodiment. [Diagram 3] FIG. 4 is an explanatory diagram showing the relationship between a driving mode and the state of each clutch. [Figure 4] 4 is a collinear diagram showing a power transmission device, a relationship between the rotation speed of the rear wheels, and a torque balance relationship in a normal driving mode; FIG. [Diagram 5]FIG. 4 is a collinear diagram illustrating the relationship between the rotation speed of the rear wheels and the torque balance relationship in the power transmission device in a left-right reverse mode. [Figure 6] FIG. 4 is an explanatory diagram showing an example of the behavior of the vehicle in a left-right reverse mode. [Figure 7] FIG. 4 is a schematic configuration diagram showing a power transmission device according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

[0017] [First embodiment] 1 is a schematic diagram showing a vehicle equipped with a power transmission device of a first embodiment. The vehicle 1 is equipped with front wheels 2R, 2L as driven wheels, and rear wheels 3R ​​(first drive wheels) and rear wheels 3L (second drive wheels) as drive wheels, and is capable of running by driving the rear wheels 3R, 3L with the output of an engine 10 (power source). In the vehicle 1, power from the engine 10 is transmitted to the power transmission device 20A via a transmission 12 and a propeller shaft 14, and is further transmitted to the rear wheel 3R via a drive shaft 16R and to the rear wheel 3L via a drive shaft 16L. The drive shafts 16R, 16L are arranged coaxially.

[0018] The engine 10 is an internal combustion engine such as a gasoline engine. The transmission 12 receives rotation output from the engine 10, changes the speed at a predetermined gear ratio, and outputs the rotation to a propeller shaft 14. The transmission 12 also switches between driving ranges such as a neutral range, a parking range, a forward range (D range), and a reverse range (R range) according to a shift position set by the driver operating a shift lever (not shown). The transmission 12 may be a stepped transmission or a continuously variable transmission. The engine 10 and the transmission 12 are controlled by a control device 18 mounted on the vehicle 1.

[0019] The control device 18 is a control device that performs overall control of the vehicle 1, and includes an input / output device, a memory device (ROM, RAM, non-volatile RAM, etc.), a central processing unit (CPU), etc. The control device 18 receives detection amounts such as the accelerator opening and vehicle speed detected by various sensors (not shown) and various operation information, and calculates information required for controlling the vehicle 1. Based on the calculated information, the control device 18 controls the operation of the engine 10, the transmission 12, a clutch C1 (first connecting device) and a clutch C2 (second connecting device) of the power transmission device 20A, which will be described later, and the like.

[0020] Next, the power transmission device 20A will be described with reference to Fig. 2. Fig. 2 is a schematic diagram showing the power transmission device 20A of the first embodiment. As shown in the figure, the power transmission device 20A includes a gear device 22 including a differential device 30 and a planetary gear mechanism 40, and a connecting device 24 including a clutch C1 and a clutch C2.

[0021] The differential device 30 is a bevel gear type differential device including a differential ring gear 31, a differential case 32, a pair of pinion gears 33, a first side gear 34, and a second side gear 35.

[0022] The differential ring gear 31 is connected to the propeller shaft 14 via the pinion gear 17. The differential case 32 rotates together with the differential ring gear 31 around the drive shafts 16R and 16L. The pair of pinion gears 33 are bevel gears supported by the differential case 32 so as to be rotatable around an axis perpendicular to the drive shafts 16R and 16L, and rotate together with the differential case 32 around the drive shafts 16R and 16L. The first side gear 34 and the second side gear 35 are housed in the differential case 32, mesh with the pair of pinion gears 33, and are supported so as to be rotatable around the drive shafts 16R and 16L. The first side gear 34 is a first output member connected to the drive shaft 16R and outputs power from the engine 10 to the rear wheels 3R ​​via the drive shaft 16R. The second side gear 35 is connected to the drive shaft 16L via the carrier 45 of the planetary gear mechanism 40 and the clutch C2 of the connection device 24, and serves as a second output member that outputs power from the engine 10 to the rear wheels 3L.

[0023] As a result, when the vehicle 1 travels straight, the differential device 30 rotates about the drive shafts 16R, 16L without relative rotation between the pair of pinion gears 33 and the first and second side gears 34, 35. On the other hand, when the vehicle 1 turns, the differential device 30 absorbs the difference in rotation speed between the rear wheels 3R, 3L by relative rotation between the pair of pinion gears 33 and the first and second side gears 34, 35.

[0024] The planetary gear mechanism 40 is a double-pinion type planetary gear mechanism including a ring gear 41 (fixed element), a sun gear 42 (second rotating element), a plurality of first pinion gears 43, a plurality of second pinion gears 44, and a carrier 45 (first rotating element).

[0025] The ring gear 41 is an internal gear fixed non-rotatably to the casing 25 that houses the components of the power transmission device 20A, and is arranged coaxially with the drive shafts 16R and 16L. The sun gear 42 is an external gear arranged coaxially with the ring gear 41, and is connected to the drive shaft 16L via the clutch C1. The first pinion gears 43 are external gears that mesh with the sun gear 42, and are arranged at intervals from each other along the circumferential direction of the sun gear 42. The second pinion gears 44 are external gears that mesh with the ring gear 41 and adjacent first pinion gears 43, and are arranged at intervals from each other along the circumferential direction of the sun gear 42. The carrier 45 rotates (revolves) around the drive shafts 16R, 16L together with the first pinion gears 43 and the second pinion gears 44 while holding the first pinion gears 43 and the second pinion gears 44 rotatably (freely spinning). The carrier 45 is connected to the second side gear 35 of the differential device 30, and is also connected to the drive shaft 16L via the clutch C2.

[0026] The clutch C1 is a friction engagement device that can connect and disconnect the carrier 45 of the planetary gear mechanism 40 and the drive shaft 16L, i.e., the rear wheels 3L, by switching between an engaged state and a released state. The clutch C2 is a friction engagement device that can connect and disconnect the sun gear 42 of the planetary gear mechanism 40 and the drive shaft 16L, i.e., the rear wheels 3L, by switching between an engaged state and a released state. The clutches C1 and C2 may be of either a multi-plate type or a single-plate type, and may be of either a hydraulic type or an electric type. The clutches C1 and C2 may be of a meshing type connection device. The clutches C1 and C2 are arranged coaxially with the drive shafts 16R and 16L. Therefore, the differential device 30, the planetary gear mechanism 40, and the clutches C1 and C2 are all arranged on the drive shafts 16R and 16L.

[0027] In the power transmission device 20A configured as described above, the operation of the clutches C1 and C2 is controlled by the control device 18, thereby switching the driving mode of the vehicle 1. FIG. 3 is an explanatory diagram showing the relationship between the driving mode and the state of each clutch. As shown in the figure, the driving modes of the vehicle 1 include a normal driving mode and a left-right reverse mode. The driving mode may be configured to be switchable by the driver operating a mode change switch (not shown) provided in the passenger compartment of the vehicle 1, for example. Note that the driving mode may also be configured to be switchable by the driver changing the shift position.

[0028] The normal driving mode is a mode in which the gear device 22 of the power transmission device 20A forms a first transmission path that transmits the power from the engine 10 so that the rear wheels 3R ​​and 3L rotate in the same direction. On the other hand, the left-right reverse mode is a mode in which the gear device 22 forms a second transmission path that transmits the power from the engine 10 so that the rear wheels 3R ​​and 3L rotate in opposite directions. When the driving mode is set to the normal driving mode, the control device 18 puts the clutch C1 in an engaged state and the clutch C2 in a released state. When the driving mode is set to the left-right reverse mode, the control device 18 puts the clutch C1 in a released state and the clutch C2 in an engaged state.

[0029] The normal running mode and the left-right reverse running mode will be described with reference to Figs. 4 and 5. Fig. 4 is a collinear diagram showing the relationship between the components of the power transmission device 20A in the normal running mode, the rotation speed of the rear wheels 3R ​​and 3L, and the torque balance relationship. Fig. 5 is a collinear diagram showing the relationship between the components of the power transmission device 20A in the left-right reverse running mode, the rotation speed of the rear wheels 3R ​​and 3L, and the torque balance relationship. In Figs. 4 and 5, black circles indicate rotating elements whose rotation speed is 0. In addition, for the sake of simplicity, the differential device 30 is described as a rotating element to which torque from the engine 10 is input, and the description of the absorption of the rotation speed difference between the left and right rear wheels 3R ​​and 3L by the differential device 30 is omitted.

[0030] As shown in FIG. 4, in the normal driving mode, the carrier 45 of the planetary gear mechanism 40 and the rear wheel 3L are connected by the clutch C1, and the sun gear 42 of the planetary gear mechanism 40 and the rear wheel 3L are disconnected by the clutch C2. As a result, as shown by the white arrow in the figure, when torque (power) in the forward direction is input to the differential device 30, the torque is transmitted from the first side gear 34 (see FIG. 2) of the differential device 30 to the rear wheel 3R, and a first transmission path is formed in which the torque is transmitted from the second side gear 35 (see FIG. 2) of the differential device 30 and the carrier 45 to the rear wheel 3L. Then, the torque transmitted from the differential device 30 and the reaction torque (black arrow) generated in the rear wheels 3R ​​and 3L as the driving wheels are balanced. At this time, the carrier 45 rotates in the same direction as the first side gear 34 and the second side gear 35 of the differential device 30, so that the rear wheels 3R ​​and 3L rotate in the same direction (here, the forward direction). This allows driving in forward and reverse ranges.

[0031] On the other hand, as shown in Fig. 5, in the left-right reverse mode, the clutch C1 releases the connection between the carrier 45 of the planetary gear mechanism 40 and the rear wheel 3L, and the clutch C2 connects the sun gear 42 of the planetary gear mechanism 40 and the rear wheel 3L. As a result, as shown by the white arrow in the figure, when torque in the forward direction, for example, is input to the differential device 30, the torque is transmitted from the first side gear 34 of the differential device 30 to the rear wheel 3R, and a second transmission path is formed in which the torque is transmitted from the second side gear 35 of the differential device 30, the carrier 45, and the sun gear 42 to the rear wheel 3L. The torque transmitted to the carrier 45 acts on the sun gear 42 as a torque in the reverse direction, and the torque transmitted from the differential device 30 and the reaction torque generated at the rear wheels 3R ​​and 3L (see the black arrows) are balanced. At this time, the sun gear 42 rotates in the opposite direction to the carrier 45, the first side gear 34 of the differential device 30, and the rear wheel 3R, so that the rear wheel 3L also rotates in the opposite direction to the rear wheel 3R.

[0032] FIG. 6 is an explanatory diagram showing an example of the behavior of the vehicle 1 in the left-right reverse mode. It is assumed that the driver operates the steering wheel (not shown) to tilt the front wheels 2R and 2L to the left while depressing the accelerator, with the shift position set to the forward range and the driving mode set to the left-right reverse mode. At this time, as shown by the white arrow in the figure, the rear wheel 3R rotates in the forward direction and the rear wheel 3L rotates in the backward direction. Therefore, the vehicle 1 turns around the front end portion near the front wheels 2R and 2L while slipping the rear wheels 3R ​​and 3L, as shown by the arc-shaped white arrow and the dashed line. In other words, it becomes possible to turn with a turning radius smaller than the minimum turning radius when the vehicle 1 turns in the normal driving mode, and it becomes possible to easily change direction. Note that FIG. 6 shows the turning of the vehicle 1 in the left-right reverse mode in a schematic manner, and the positions of the front wheels 2R and 2L are not necessarily fixed during turning.

[0033] As described above, the power transmission device 20A of the first embodiment includes a gear device 22 that forms a first transmission path that transmits power from the engine 10 (power source) so that the rear wheels 3R ​​(first drive wheel) and the rear wheels 3L (second drive wheel) rotate in the same direction, and a second transmission path that transmits power from the engine 10 so that the rear wheels 3R ​​and 3L rotate in the opposite direction, and a connection device 24 that switches between the connection of the rear wheels 3R ​​and 3L to the first transmission path and the connection of the rear wheels 3R ​​and 3L to the second transmission path.

[0034] With this configuration, when the first transmission path formed by the gear device 22 is selected by the connection device 24, the rear wheels 3R, 3L are rotated in the same direction, allowing the vehicle to travel normally, such as going straight or turning. On the other hand, when the second transmission path formed by the gear device 22 is selected by the connection device 24, the rear wheels 3R, 3L are rotated in the opposite direction to change the direction of the vehicle. Therefore, with the power transmission device 20A, it is possible to rotate the left and right drive wheels in both the same and opposite directions to run the vehicle, without using multiple power sources corresponding to each drive wheel (rear wheels 3R, 3L).

[0035] The gear device 22 also includes a differential device 30 that receives power from the engine 10 and outputs the input power to a first side gear 34 (first output member) connected to the rear wheel 3R and a second side gear 35 (second output member), and a planetary gear mechanism 40 that includes a ring gear 41 (fixed element), a carrier 45 (first rotating element) connected to the second side gear 35, and a sun gear 42 (second rotating element) that rotates in the opposite direction to the carrier 45 when power is transmitted from the second side gear 35 to the carrier 45. The connection device 24 includes a clutch C1 (first connection device) that connects and disconnects the rear wheel 3L and the carrier 45, and a clutch C2 (second connection device) that connects and disconnects the rear wheel 3L and the sun gear 42.

[0036] With this configuration, the rear wheel 3R rotates in the same direction as the first side gear 34 of the differential device 30. When the rear wheel 3L and the carrier 45 are connected by the clutch C1, the first transmission path is formed, and the rear wheels 3R ​​and 3L rotate in the same direction. On the other hand, when the rear wheel 3L and the sun gear 42 are connected by the clutch C2, the second transmission path is formed, and the rear wheels 3R ​​and 3L rotate in the opposite directions. Therefore, by simply adding the planetary gear mechanism 40 and the clutches C1 and C2 to the differential device 30 to which the power is input from the engine 10, a configuration can be realized in which the left and right rear wheels 3R ​​and 3L rotate in both the same direction and the opposite directions, and the structure of the power transmission device 20A can be prevented from becoming complicated.

[0037] Moreover, the planetary gear mechanism 40 includes a ring gear 41 as a fixed element, a sun gear 42 as a second rotating element, a plurality of first pinion gears 43 meshing with the sun gear 42, a plurality of second pinion gears 44 meshing with the ring gear 41 and the plurality of first pinion gears 43, and a carrier 45 as a first rotating element that rotatably holds the plurality of first pinion gears 43 and the plurality of second pinion gears 44 and revolves together with the plurality of first pinion gears 43 and the plurality of second pinion gears 44. This configuration makes it possible to realize a configuration in which the left and right rear wheels 3R, 3L are rotated in both the same direction and in opposite directions using the double pinion type planetary gear mechanism 40, and makes it possible to suppress the complication of the structure of the power transmission device 20A.

[0038] Moreover, the differential 30 is a bevel gear type differential including a first side gear 34 as a first output member and a second side gear 35 as a second output member. With this configuration, it is possible to realize a configuration in which the left and right rear wheels 3R, 3L are rotated in both the same direction and the opposite directions using the bevel gear type differential 30, and it is possible to suppress the structure of the power transmission device 20A from becoming complicated.

[0039] Moreover, the differential device 30, the planetary gear mechanism 40, and the clutches C1, C2 are disposed on the drive shafts 16R, 16L. This configuration makes it possible to prevent the power transmission device 20A from becoming large in diameter.

[0040] [Second embodiment] Next, a power transmission device of a second embodiment will be described. Fig. 7 is a schematic diagram showing a power transmission device 20B of the second embodiment. The power transmission device 20B includes a differential device 50 instead of the differential device 30. Since other components of the power transmission device 20B are similar to those of the power transmission device 20A, detailed description thereof will be omitted and the same components will be denoted by the same reference numerals.

[0041] 7, the differential device 50 includes a differential-side ring gear 51, a differential-side sun gear 52, a plurality of differential-side first pinion gears 53, a plurality of differential-side second pinion gears 54, and a differential-side carrier 55. In other words, the differential device 50 is configured as a double-pinion planetary gear mechanism type differential device.

[0042] The differential side ring gear 51 is an internal gear connected to the propeller shaft 14 via the pinion gear 17, to which power from the engine 10 is input, and is disposed coaxially with the drive shafts 16R, 16L. The differential side sun gear 52 is an external gear disposed coaxially with the differential side ring gear 51, and is connected to the drive shaft 16R. The differential side sun gear 52 is a first output member that outputs power from the engine 10 to the rear wheel 3R via the drive shaft 16R.

[0043] The multiple differential side first pinion gears 53 are external gears that mesh with the differential side sun gear 52, and are arranged at intervals from one another in the circumferential direction of the differential side sun gear 52. The multiple differential side second pinion gears 54 are external gears that mesh with adjacent differential side first pinion gears 53 and differential side ring gear 51, and are arranged at intervals from one another in the circumferential direction of the differential side sun gear 52.

[0044] The differential side carrier 55 rotates (revolves) around the drive shafts 16R, 16L together with the multiple differential side first pinion gears 53 and the multiple differential side second pinion gears 54 while holding the multiple differential side first pinion gears 53 and the multiple differential side second pinion gears 54 rotatably (rotatably). The differential side carrier 55 is connected to the carrier 45 of the planetary gear mechanism 40 and rotates around the drive shafts 16R, 16L together with the carrier 45. In other words, the differential side carrier 55 is connected to the drive shaft 16L via the carrier 45 of the planetary gear mechanism 40 and the clutch C2 of the connection device 24, and is a second output member that outputs power from the engine 10 to the rear wheel 3L. The carrier 45 and the differential side carrier 55 may be configured as an integral member.

[0045] As a result, when the vehicle 1 travels straight, the differential device 50 rotates about the drive shafts 16R, 16L without relative rotation between the differential side carrier 55 and the differential side sun gear 52. On the other hand, when the vehicle 1 turns, the differential device 50 absorbs the difference in rotation speed between the rear wheels 3R, 3L by relative rotation between the differential side carrier 55 and the differential side sun gear 52.

[0046] Even when the planetary gear mechanism type differential 50 is used, the operation of the clutches C1, C2 can be switched as shown in Fig. 3 to switch between the normal driving mode and the left / right reverse rotation mode, as in the power transmission device 20A of the first embodiment. That is, the elements of the differential device 30 shown in Figs. 4 and 5 are replaced with the differential device 50. In this way, a configuration in which the left and right driving wheels are rotated in both the same direction and the opposite directions can be realized using the planetary gear mechanism type differential device 50, and the structure of the power transmission device 20B can be prevented from becoming complicated.

[0047] Also in the power transmission device 20B, the differential device 50, the planetary gear mechanism 40, and the clutches C1, C2 are disposed on the drive shafts 16R, 16L. This configuration makes it possible to prevent the power transmission device 20B from becoming larger in diameter.

[0048] Although the description of the embodiment is finished above, the aspects of the present invention are not limited to this embodiment. For example, in the first and second embodiments, a double-pinion type planetary gear mechanism is used as the planetary gear mechanism 40, but the planetary gear mechanism 40 may include a fixed element, a first rotating element connected to the second output member of the differential device 30, 50, and a second rotating element that rotates in the opposite direction to the first rotating element.

[0049] Furthermore, at least one of the differential device 30 or 50, the planetary gear mechanism 40, and the clutches C1 and C2 does not have to be disposed coaxially with the drive shafts 16R and 16L.

[0050] Furthermore, in a four-wheel drive vehicle in which both the front wheels 2R, 2L and the rear wheels 3R, 3L are driven, the power transmission devices 20A, 20B may be applied to both a power transmission device that transmits power from the engine 10 to the front wheels 2R, 2L and a power transmission device that transmits power to the rear wheels 3R, 3L. Furthermore, the power source may be another power source such as an electric motor.

[0051] Furthermore, as long as the power transmission devices 20A, 20B are provided with a gear device that forms the first transmission path and the second transmission path, and a connection device that switches between the connection between the rear wheels 3R, 3L and the first transmission path and the connection between the rear wheels 3R, 3L and the second transmission path, they may include components such as other gear devices, planetary gear mechanisms, gears, clutches, etc., and are not limited to those shown in the first and second embodiments. [Explanation of symbols]

[0052] 1 vehicle 2R, 2L front wheel 3L rear wheel (second drive wheel) 3R Rear wheel (first drive wheel) 10 Engine (power source) 16R, 16L drive shaft 20A, 20B Power transmission device 22 Gearing 24 Connection Device 25 Casing 30, 50 differential 34 First side gear (first output member) 35 Second side gear (second output member) 40 Planetary Gear Mechanism 41 Ring gear (fixed element) 42 Sun gear (second rotating element) 43 1st pinion gear 44 2nd pinion gear 45 Carrier (first rotating element) 51 Differential ring gear 52 Differential side sun gear (first output member) 53 Differential side first pinion gear 54 Differential side second pinion gear 55 Differential side carrier (second output member) C1 Clutch (first connecting device) C2 Clutch (second connecting device)

Claims

1. A power transmission device that is mounted on a vehicle and transmits power from a power source to left and right first and second drive wheels, a gear device that forms a first transmission path that transmits power from the power source so that the first drive wheel and the second drive wheel rotate in the same direction, and a second transmission path that transmits power from the power source so that the first drive wheel and the second drive wheel rotate in opposite directions; a connection device that switches between a connection between the first drive wheel and the second drive wheel and the first transmission path and a connection between the first drive wheel and the second drive wheel and the second transmission path; A power transmission device comprising:

2. The gear device comprises: a differential device that receives power from the power source and outputs the input power to a first output member connected to the first drive wheel and to a second output member; a planetary gear mechanism including a fixed element, a first rotating element connected to the second output member, and a second rotating element that rotates in a direction opposite to that of the first rotating element when power is transmitted from the second output member to the first rotating element, The connection device includes: a first connection device that connects and disconnects the second drive wheel and the first rotating element; a second connection device that connects and disconnects the second drive wheel and the second rotating element; The power transmission device according to claim 1 , comprising:

3. The planetary gear mechanism includes: A ring gear as the fixed element; a sun gear as the second rotating element; a plurality of first pinion gears meshing with the sun gear; a plurality of second pinion gears meshing with the ring gear and the plurality of first pinion gears; a carrier serving as the first rotating element that rotatably holds the plurality of first pinion gears and the plurality of second pinion gears and revolves together with the plurality of first pinion gears and the plurality of second pinion gears; 3. The power transmission device of claim 2, comprising:

4. 4. The power transmission device according to claim 2, wherein the differential device is a bevel gear type differential device including a first side gear as the first output member and a second side gear as the second output member.

5. The differential device includes: a differential side ring gear to which power from the power source is input; a differential-side sun gear as the first output member; a plurality of differential side first pinion gears meshing with the differential side sun gear; a plurality of differential side second pinion gears meshing with the differential side ring gear and the plurality of differential side first pinion gears; a differential side carrier serving as the second output member that rotatably holds the plurality of differential side first pinion gears and the plurality of differential side second pinion gears and revolves together with the plurality of differential side first pinion gears and the plurality of differential side second pinion gears; The power transmission device according to claim 2 or 3, comprising:

6. 4. The power transmission device according to claim 2, wherein the differential device, the planetary gear mechanism, the first connecting device and the second connecting device are arranged side by side on a drive shaft.

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