Drive unit

Abstract

To provide a drive unit which enables compactification.SOLUTION: A drive unit includes: a rotary electric machine; a first fluid joint; and a differential gear. The first fluid joint is configured to transmit power output from the rotary electric machine through a working fluid. The differential gear is coaxially arranged with the first fluid joint. The differential gear is configured to enable differential rotation of a pair of driving wheels.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a drive unit. [Background technology]

[0002] In recent years, electric vehicles having a torque converter have been proposed. For example, the drive unit of an electric vehicle described in Patent Document 1 has an electric motor, a torque converter, and a differential gear. The power from the electric motor is amplified by the torque converter. The power amplified by the torque converter is then transmitted to each drive wheel via the differential gear. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-205831 A Summary of the Invention [Problem to be solved by the invention]

[0004] There is a demand for making the above-mentioned drive unit more compact. Therefore, an object of the present invention is to provide a drive unit that can be made compact. [Means for solving the problem]

[0005] A drive unit according to an aspect of the present invention is configured to drive a pair of drive wheels to rotate. The drive unit includes a rotating electric machine, a first fluid coupling, and a differential gear. The first fluid coupling is configured to transmit power output from the rotating electric machine via a working fluid. The differential gear is disposed coaxially with the first fluid coupling. The differential gear is configured to enable differential rotation of the pair of drive wheels.

[0006] According to this configuration, the first fluid coupling and the differential device are arranged coaxially, making it possible to make the device compact.

[0007] Preferably, the rotating electric machine is disposed coaxially with the first fluid coupling and the differential device.

[0008] Preferably, the drive unit further includes a reducer or a transmission. The reducer is configured to reduce the speed of the power from the rotating electric machine. The transmission is configured to change the speed of the power from the rotating electric machine.

[0009] Preferably, the speed reducer or transmission is arranged coaxially with the first fluid coupling and the differential.

[0010] Preferably, the reducer or the transmission is disposed in the power transmission path between the rotating electric machine and the first fluid coupling.

[0011] Preferably, the reduction gear or transmission is disposed in the power transmission path between the first fluid coupling and the differential.

[0012] Preferably, the drive unit further includes a forward / reverse switching device configured to switch the rotation direction of the power output from the rotating electric machine.

[0013] Preferably, the forward / reverse switching device is disposed coaxially with the first fluid coupling and the differential device.

[0014] Preferably, the forward / reverse switching device is disposed in the power transmission path between the first fluid coupling and the differential device.

[0015] Preferably, the differential gear is disposed axially between the rotating electric machine and the first fluid coupling.

[0016] Preferably, the rotating electric machine is disposed radially outward from the first fluid coupling.

[0017] Preferably, the rotating electric machine is disposed radially outwardly of the differential device.

[0018] Preferably, the drive unit further includes a countershaft. The countershaft is disposed on a different axis from the first fluid coupling and the differential gear. The countershaft is disposed between the first fluid coupling and the differential gear in the power transmission path.

[0019] Preferably, the countershaft is configured to transmit the power from the first fluid coupling to the differential device after reducing or changing the speed.

[0020] Preferably, the rotating electric machine is disposed on a different axis from that of the first fluid coupling.

[0021] Preferably, the reducer or the transmission is arranged coaxially with the rotating electric machine.

[0022] Preferably, the drive unit further includes a second fluid coupling. The second fluid coupling is arranged coaxially with the first fluid coupling and the differential gear. The first fluid coupling is configured to transmit the power output from the differential gear to the first drive wheel via the working fluid. The second fluid coupling is configured to transmit the power output from the differential gear to the second drive wheel via the working fluid. Effect of the Invention

[0023] According to the present invention, the drive unit can be made compact. [Brief description of the drawings]

[0024] [Figure 1] FIG. 2 is a schematic diagram of a drive unit according to the embodiment. [Diagram 2] FIG. 11 is a schematic diagram of a drive unit according to a modified example. [Diagram 3] FIG. 11 is a schematic diagram of a drive unit according to a modified example. [Figure 4] FIG. 11 is a schematic diagram of a drive unit according to a modified example. [Diagram 5] FIG. 11 is a schematic diagram of a drive unit according to a modified example. [Figure 6] FIG. 11 is a schematic diagram of a drive unit according to a modified example. [Figure 7] FIG. 11 is a schematic diagram of a drive unit according to a modified example. [Figure 8] FIG. 11 is a schematic diagram of a drive unit according to a modified example. [Figure 9] FIG. 11 is a schematic diagram of a drive unit according to a modified example. [Figure 10] FIG. 11 is a schematic diagram of a drive unit according to a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] Hereinafter, the drive unit according to this embodiment will be described with reference to the drawings. In the following description, the axial direction is the direction in which the rotation axis O of the differential gear 4 extends. Moreover, the radial direction is the radial direction of a circle centered on the rotation axis O.

[0026] <Drive unit 100> 1, the drive unit 100 includes an electric motor (an example of a rotating electric machine) 2, a first torque converter (an example of a first fluid coupling) 3, and a differential gear 4 (an example of a differential device). The first torque converter 3 is disposed between the electric motor 2 and the differential gear 4 in the axial direction. That is, the electric motor 2, the first torque converter 3, and the differential gear 4 are disposed in this order in the axial direction.

[0027] The drive unit 100 is mounted on an electric vehicle. The drive unit 100 may also be mounted on a hybrid vehicle. The drive unit 100 is configured to drive a pair of drive wheels 101 to rotate.

[0028] <Electric motor 2> The electric motor 2 has a first stator 21 and a rotor 22. The first stator 21 is fixed to a frame, a housing, or the like. The first stator 21 is non-rotatable.

[0029] The rotor 22 is rotatable about a rotation axis O. The rotor 22 is disposed radially inward relative to the first stator 21. That is, the electric motor 2 is an inner rotor type. The electric motor 2 may be an outer rotor type. The rotor 22 is rotatable relative to the drive shaft 103.

[0030] The electric motor 2 is disposed coaxially with the differential gear 4. That is, the rotation shaft of the electric motor 2 is disposed substantially on the same line as the rotation shaft O of the differential gear 4. Note that the rotation shaft of the electric motor 2 is the rotation shaft of the rotor 22.

[0031] <First torque converter 3> The first torque converter 3 is configured to transmit the power output from the electric motor 2 via a hydraulic fluid (e.g., hydraulic oil). The first torque converter 3 is disposed coaxially with the differential gear 4. That is, the rotation axis of the first torque converter 3 is disposed substantially on the same line as the rotation axis O of the differential gear 4. The first torque converter 3 is rotatable relative to the drive shaft 103.

[0032] The first torque converter 3 has a cover 31, an impeller 32, a turbine 33, and a second stator .

[0033] Power from the electric motor 2 is transmitted to the cover 31. The cover 31 is attached to the rotor 22 of the electric motor 2. The cover 31 rotates integrally with the rotor 22 of the electric motor 2. Note that another member may be interposed between the cover 31 and the rotor 22. Furthermore, the cover 31 may rotate at a different rotation speed from the rotor 22.

[0034] The impeller 32 is fixed to the cover 31. The impeller 32 rotates integrally with the cover 31.

[0035] The turbine 33 is disposed so as to face the impeller 32. Power is transmitted to the turbine 33 from the impeller 32 via the working fluid.

[0036] The second stator 34 is disposed between the impeller 32 and the turbine 33. The second stator 34 is attached to the fixed shaft 104 via a one-way clutch (not shown).

[0037] <Differential gear 4> Power is transmitted from the first torque converter 3 to the differential gear 4. That is, the electric motor 2, the first torque converter 3, and the differential gear 4 are arranged in this order in the power transmission path.

[0038] The differential gear 4 is configured to distribute and transmit the power from the first torque converter 3 to the two drive wheels 101. The differential gear 4 is configured to enable differential rotation of the pair of drive wheels 101. In detail, the differential gear 4 is configured to enable differential rotation of a pair of drive shafts 103.

[0039] The differential gear 4 is disposed coaxially with the first torque converter 3. That is, the rotation axis O of the differential gear 4 and the rotation axis of the first torque converter 3 are disposed substantially on the same line.

[0040] The differential gear 4 has a pinion gear 41 and a pair of side gears 42. Power is transmitted to the pinion gear 41 from the turbine 33. The rotation shaft of the pinion gear 41 extends in the radial direction. The pinion gear 41 is disposed to rotate on its own axis and revolve around the rotation axis O.

[0041] Each side gear 42 meshes with a pinion gear 41. Each side gear 42 transmits the power transmitted from the pinion gear 41 to a corresponding drive shaft 103.

[0042] [Variations] Although the embodiments of the present invention have been described above, the present invention is not limited to these, and various modifications are possible without departing from the spirit of the present invention.

[0043] Variation 1 2, the drive unit 100 may further include a reduction gear 5. The reduction gear 5 is arranged coaxially with the first torque converter 3 and the differential gear 4. The reduction gear 5 is also arranged coaxially with the electric motor 2. The reduction gear 5 is composed of, for example, a plurality of gears.

[0044] The reduction gear 5 is disposed in the power transmission path between the electric motor 2 and the first torque converter 3. That is, the reduction gear 5 reduces the speed of the power from the electric motor 2 and outputs it to the first torque converter 3.

[0045] The reduction gear 5 is disposed between the electric motor 2 and the first torque converter 3 in the axial direction. That is, the electric motor 2, the reduction gear 5, and the first torque converter 3 are disposed in this order in the axial direction. In detail, the electric motor 2, the reduction gear 5, the first torque converter 3, and the differential gear 4 are disposed in this order in the axial direction.

[0046] 3, the reduction gear 5 may be disposed in the power transmission path between the first torque converter 3 and the differential gear 4. That is, the reduction gear 5 may reduce the power from the first torque converter 3 and output it to the differential gear 4.

[0047] The reduction gear 5 is disposed between the first torque converter 3 and the differential gear 4 in the axial direction. That is, the first torque converter 3, the reduction gear 5, and the differential gear 4 are disposed in this order in the axial direction. In detail, the electric motor 2, the first torque converter 3, the reduction gear 5, and the differential gear 4 are disposed in this order in the axial direction.

[0048] In each of the above-described modified examples, the drive unit 100 may include a transmission instead of the reduction gear 5, or may include a forward / reverse switching device. The forward / reverse switching device is configured to switch the rotation direction of the power output from the electric motor 2. The forward / reverse switching device is configured with a plurality of gears.

[0049] The forward / reverse switching device is preferably disposed between the first torque converter 3 and the differential gear 4 in the power transmission path. That is, the forward / reverse switching device is configured to switch the rotation direction of the power output by the first torque converter 3. With this configuration, the rotation direction of the power input to the first torque converter 3 can be made the same both when traveling forward and when traveling backward.

[0050] Variation 2 4, the differential gear 4 may be disposed between the electric motor 2 and the first torque converter 3 in the axial direction. That is, the electric motor 2, the differential gear 4, and the first torque converter 3 are disposed in this order in the axial direction. Note that the power transmission path is in the order of the electric motor 2, the first torque converter 3, and the differential gear 4.

[0051] Variation 3 5, the electric motor 2 may be disposed radially outward from the first torque converter 3. That is, the electric motor 2 may overlap the first torque converter 3 when viewed in the radial direction. In the axial direction, the electric motor 2 and the first torque converter 3 are disposed at the same position.

[0052] The electric motor 2 is disposed so as to surround the first torque converter 3. The electric motor 2 is attached to the outer circumferential surface of the first torque converter 3. In particular, the rotor 22 of the electric motor 2 is attached to the outer circumferential surface of the cover 31 or the impeller 32 of the first torque converter 3. Note that another member may be interposed between the rotor 22 and the cover 31 or the impeller 32.

[0053] Variation 4 6, the electric motor 2 may be disposed radially outward from the differential gear 4. That is, the electric motor 2 may overlap with the differential gear 4 when viewed in the radial direction. In the axial direction, the electric motor 2 and the differential gear 4 are disposed at the same position.

[0054] The electric motor 2 is disposed so as to surround the differential gear 4. The power transmission path is the electric motor 2, the first torque converter 3, and the differential gear 4 in that order.

[0055] Variation 5 7, the drive unit 100 may further include a countershaft 6. The countershaft 6 is disposed on a different axis from the first torque converter 3 and the differential gear 4. In other words, the rotation axis of the countershaft 6 is not disposed on the same line as the rotation axis O of the first torque converter 3 and the differential gear 4. The rotation axis of the countershaft 6 extends substantially parallel to the rotation axis O of the first torque converter 3 and the differential gear 4.

[0056] The countershaft 6 is disposed in the power transmission path between the first torque converter 3 and the differential gear 4. That is, the first torque converter 3 transmits power to the differential gear 4 via the countershaft 6.

[0057] The counter shaft 6 is configured to reduce the speed of the power from the first torque converter 3 and transmit it to the differential gear 4. That is, the counter shaft 6 functions as a reducer. For example, the counter shaft 6 has a plurality of gears.

[0058] In this case, for example, the differential gear 4 has a ring gear (not shown). One of the gears of the counter shaft 6 meshes with the ring gear of the differential gear 4 to rotate the ring gear. The rotation of the ring gear causes the pinion gear 41 to revolve around the rotation axis O.

[0059] The counter shaft 6 may be configured to change the speed of the power from the first torque converter 3 and transmit it to the differential gear 4. In other words, the counter shaft 6 may have a transmission.

[0060] Variation 6 8, the electric motor 2 may be disposed on a different axis from the first torque converter 3. In other words, the rotation axis of the electric motor 2 is not disposed on the same line as the rotation axis O of the first torque converter 3 and the differential gear 4. The rotation axis of the electric motor 2 extends substantially parallel to the rotation axis O of the first torque converter 3 and the differential gear 4.

[0061] In this case, for example, power is transmitted from the electric motor 2 to the first torque converter 3 as follows. First, the electric motor 2 has an output shaft 23 and a gear 24. The gear 24 is attached to the output shaft 23.

[0062] The first torque converter 3 has a ring gear 35. The ring gear 35 is provided on the cover 31, for example, but may be provided on the impeller 32 or the like. The ring gear 35 may be a separate member from the cover 31, or may be a single member. The gear 24 of the electric motor 2 meshes with this ring gear 35, thereby transmitting power from the electric motor 2 to the first torque converter 3. Note that another member may be interposed between the electric motor 2 and the first torque converter 3.

[0063] In this modified example, as shown in Fig. 9, the reduction gear 5 may be disposed coaxially with the electric motor 2. The reduction gear 5 may be disposed coaxially with the differential gear 4. Note that a transmission may be provided instead of the reduction gear 5.

[0064] Variation 7 10, the drive unit 100 may further include a second torque converter 7. The second torque converter 7 is disposed coaxially with the first torque converter 3 and the differential gear 4. That is, the rotation axis of the second torque converter 7 is disposed substantially on the same line as the rotation axis O of the first torque converter 3 and the differential gear 4.

[0065] In this modified example, the order of the torque converters 3, 7 and the differential gear 4 in the power transmission path is reversed. That is, the power transmission path has the electric motor 2, the differential gear 4, and the torque converters 3, 7 in this order.

[0066] Specifically, the first torque converter 3 is configured to transmit the power output from the differential gear 4 to the first driving wheel 101a. More specifically, the power from the first side gear 42a of the differential gear 4 is transmitted to the cover 31 of the first torque converter 3.

[0067] The power transmitted to the cover 31 is transmitted in this order to the impeller 32, the working fluid, and the turbine 33. Then, the first torque converter 3 transmits the power from the turbine 33 to the first driving wheel 101a.

[0068] The second torque converter 7 is configured to transmit the power output from the differential gear 4 to the second driving wheel 101b. In detail, the second torque converter 7 has a cover 71, an impeller 72, a turbine 73, and a second stator 74. Power from the second side gear 42b of the differential gear 4 is transmitted to the cover 71 of the second torque converter 7.

[0069] The power transmitted to the cover 71 of the second torque converter 7 is transmitted in this order to the impeller 72, the working fluid, and the turbine 73. Then, the second torque converter 7 transmits the power from the turbine 73 to the second driving wheel 101b.

[0070] Variation 8 In the above embodiment, the differential gear 4 is illustrated as an example of a differential device, but the differential device is not limited to this. For example, the differential device may be a torque vectoring device. [Explanation of symbols]

[0071] 2: Electric motor 3: First torque converter 4: Differential gear 5: Reducer 6: Countershaft 7: Second torque converter 100: Drive unit 101: Drive wheel

Claims

1. A drive unit that drives a pair of drive wheels to rotate, A rotating electric machine; a first fluid coupling configured to transmit power output from the rotating electric machine via a working fluid; a differential device arranged coaxially with the first fluid coupling and configured to enable differential rotation of a pair of drive wheels; Equipped with The differential device is disposed between the rotating electric machine and the first fluid coupling in the axial direction. Drive unit.

2. A drive unit that rotates a pair of drive wheels, A rotating electric machine; a first fluid coupling configured to transmit power output from the rotating electric machine via a working fluid; a differential device arranged coaxially with the first fluid coupling and configured to enable differential rotation of a pair of drive wheels; Equipped with The rotating electric machine is disposed radially outward from the first fluid coupling. Drive unit.

3. A drive unit that rotates a pair of drive wheels, A rotating electric machine; a first fluid coupling configured to transmit power output from the rotating electric machine via a working fluid; a differential device arranged coaxially with the first fluid coupling and configured to enable differential rotation of a pair of drive wheels; a second fluid coupling arranged coaxially with the first fluid coupling and the differential device; Equipped with the first fluid coupling is configured to transmit the power output from the differential device to a first drive wheel via a working fluid; The second fluid coupling is configured to transmit the power output from the differential device to a second drive wheel via a working fluid. Drive unit.

4. the rotating electric machine is disposed coaxially with the first fluid coupling and the differential device; A drive unit according to any one of claims 1 to 3.

5. Further comprising a reducer configured to reduce the speed of the power from the rotating electric machine, or a transmission configured to change the speed of the power from the rotating electric machine. A drive unit according to any one of claims 1 to 4.

6. The reduction gear or transmission is disposed coaxially with the first fluid coupling and the differential gear. A drive unit according to claim 5.

7. The reduction gear or the transmission is disposed between the rotating electric machine and the first fluid coupling in a power transmission path. A drive unit according to claim 5 or 6.

8. The reduction gear or the transmission is disposed between the first fluid coupling and the differential device in a power transmission path. A drive unit according to claim 5 or 6.

9. The vehicle further includes a forward / reverse switching device configured to switch the rotation direction of the power output from the rotating electric machine. A drive unit according to any one of claims 1 to 8.

10. The forward / reverse switching device is disposed coaxially with the first fluid coupling and the differential device. A drive unit according to claim 9.

11. The forward / reverse switching device is disposed between the first fluid coupling and the differential device in a power transmission path. A drive unit according to claim 9 or 10.

12. The differential device is disposed between the rotating electric machine and the first fluid coupling in the axial direction. A drive unit according to claim 2 or 3.

13. The rotating electric machine is disposed radially outward from the first fluid coupling. A drive unit according to claim 1 or 3.

14. The rotating electric machine is disposed radially outward from the differential device. A drive unit according to claim 1 or 3.

15. A counter shaft is further provided which is arranged on a different axis from the first fluid coupling and the differential device, The countershaft is disposed between the first fluid coupling and the differential device in a power transmission path. A drive unit according to any one of claims 1 to 14.

16. The countershaft is configured to reduce or change the speed of the power from the first fluid coupling and transmit it to the differential device.

16. A drive unit according to claim 15.

17. The rotating electric machine is disposed on a different axis from the first fluid coupling. A drive unit according to any one of claims 1 to 14.

18. The reduction gear or the transmission is arranged coaxially with the rotating electric machine. A drive unit according to claim 17 when dependent on claim 5.

19. a second fluid coupling arranged coaxially with the first fluid coupling and the differential gear; the first fluid coupling is configured to transmit the power output from the differential device to a first drive wheel via a working fluid; The second fluid coupling is configured to transmit the power output from the differential device to a second drive wheel via a working fluid. A drive unit according to claim 1 or 2.

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