阅读说明：本技术 混合电驱动装置 (Hybrid electric drive device ) 是由 夏承钢 韦小田 赵成 叶伟飞 张于于 孙江明 于 2021-09-28 设计创作，主要内容包括：本发明涉及一种混合电驱动装置,包括发动机、第一电机、第二电机、变速机构、第一输入轴、第二输入轴、第三输入轴、中间轴、输出轴、后传动齿轮组、第一挡位齿轮组、第二挡位齿轮组、第三挡位齿轮组,第一电机与第一输入轴相连,第二电机与第二输入轴相连,发动机与第三输入轴相连。采用了本发明的混合电驱动装置,车辆中低速行驶时,与第三输入轴啮合相关齿轮不被拖动,车辆中高速行驶时,第一电机和第一输入轴啮合相关齿轮不被拖动,降低内部的拖曳损失,提高电驱动系统能效。在高压电气系统出现故障时可通过第一换挡元件和第二换挡元件挂空挡使第一电机和第二电机不被发动机拖动,发动机单独驱动车辆完成跛足回家,从而功能完整且提升能效。(The invention relates to a hybrid electric drive device which comprises an engine, a first motor, a second motor, a speed change mechanism, a first input shaft, a second input shaft, a third input shaft, an intermediate shaft, an output shaft, a rear transmission gear set, a first gear set, a second gear set and a third gear set, wherein the first motor is connected with the first input shaft, the second motor is connected with the second input shaft, and the engine is connected with the third input shaft. By adopting the hybrid electric drive device, when the vehicle runs at a low speed, the gear engaged with the third input shaft is not dragged, and when the vehicle runs at a high speed, the gear engaged with the first input shaft is not dragged, so that the internal dragging loss is reduced, and the energy efficiency of an electric drive system is improved. When the high-voltage electrical system is in failure, the first shifting element and the second shifting element can be used for engaging neutral gear, so that the first motor and the second motor are not dragged by the engine, and the engine independently drives the vehicle to complete limp home, so that the function is complete and the energy efficiency is improved.)

1. A hybrid electric drive device is characterized by comprising an engine, a first motor, a second motor, a speed change mechanism, a first input shaft, a second input shaft, a third input shaft, an intermediate shaft, an output shaft, a rear transmission gear set, a first gear set, a second gear set and a third gear set, wherein the first motor is connected with the first input shaft, the second motor is connected with the second input shaft, the engine is connected with the third input shaft, and the intermediate shaft is connected with the output shaft through the rear transmission gear set; the first gear set is arranged between the first input shaft and the intermediate shaft, the second gear set is arranged between the second input shaft and the intermediate shaft, the third gear set is arranged between the third input shaft and the intermediate shaft, and the engine is connected with the third input shaft through the main clutch.

2. A hybrid electric drive as set forth in claim 1 wherein said first input shaft, said second input shaft, said third input shaft, and said output shaft are coaxially disposed with said first input sleeve disposed outboard of said second input shaft and said second input sleeve disposed outboard of said third input shaft.

3. The hybrid electric drive of claim 1 further comprising a first shift element selectively engaging said first input shaft with said second input shaft and a second shift element selectively engaging said second input shaft with said third input shaft.

4. The hybrid electric drive of claim 1 wherein said third gear gearset comprises a first gear gearset, a reverse gear gearset, and a third shift element, said first gear gearset comprising a first gear drive gear and a reverse gear driven gear, said reverse gear gearset comprising a reverse gear drive gear, a reverse gear idler gear, and a reverse gear driven gear, said first gear drive gear and said reverse gear drive gear being fixedly connected to said third input shaft, said first gear driven gear and said reverse gear driven gear being loosely received on said intermediate shaft and selectively engageable with said intermediate shaft through said third shift element.

5. The hybrid electric drive of claim 1 wherein said first gear gearset comprises a second gear gearset, a third gear gearset, and a fourth shifting element, said second gear gearset comprising a second drive gear and a second driven gear, said third gear gearset comprising a third drive gear and a third driven gear, said second drive gear and said third drive gear being fixedly connected to said first input shaft, said second driven gear and said third driven gear being free-sleeved on said countershaft and selectively engageable with said countershaft by said fourth shifting element.

6. The hybrid electric drive device according to claim 1, wherein the second gear set includes a fourth gear set and a highest gear set, the fourth gear set includes a fourth gear driving gear and a fourth gear driven gear, the highest gear set includes a highest gear driving gear and a highest gear driven gear, the fourth gear driving gear is freely sleeved on the second input shaft and selectively connected with the second input shaft through the first shifting element, the fourth gear driven gear is fixedly connected with the intermediate shaft, the highest gear driving gear is freely sleeved on the third input shaft and selectively connected with the third input shaft through the second shifting element, and the highest gear driven gear is fixedly connected with the intermediate shaft.

7. The hybrid electric drive device according to claim 6, wherein the second gear set further comprises a fifth gear set, a sixth gear set and a fifth shifting element, the fifth gear set comprises a fifth gear driving gear and a fifth gear driven gear, the sixth gear set comprises a sixth gear driving gear and a sixth gear driven gear, the fifth gear driving gear and the sixth gear driving gear are fixedly connected to the second input shaft, and the fifth gear driven gear and the sixth gear driven gear are freely sleeved on the intermediate shaft and selectively connected with the intermediate shaft through the fifth shifting element.

Technical Field

The invention relates to the technical field of vehicle transmission and driving, in particular to the field of hybrid electric driving, and particularly relates to a hybrid electric driving device.

Background

In the conventional commercial vehicle hybrid electric drive device, a motor module is mostly arranged between a clutch and a gearbox to form a parallel hybrid electric drive device, when a motor pushes a vehicle to start to a certain speed, the clutch is connected with an engine to start driving the vehicle, the motor can boost or switch to a power generation mode to generate power to charge an electric storage device; in the operation process, the motor can boost or generate power according to an energy management strategy, and the working point of the engine is adjusted to be close to a BSFC curve so as to improve the energy efficiency; when the vehicle brakes, the motor is switched to a regenerative braking mode, and energy is recovered to charge the power storage device. There is also a series hybrid electric drive on a commercial vehicle, i.e. the engine does not directly drive the vehicle, it only works in the high efficiency region to drive the generator to generate electricity, and the driving motor drives the vehicle directly or through the gearbox.

The hybrid electric drive device described above inevitably has the following problems: when a high-voltage electrical system fails, for example, an electric storage device or a motor fails, the high-voltage electrical system does not have a function of limping home, which is a serious problem for a vehicle transporting goods, and the goods cannot be transported to a destination at any time, and the goods required for storage may be damaged, so that the demand of a commercial vehicle cannot be fully satisfied. Even in the case of a parallel hybrid electric drive, there is a loss of energy when the engine is running and there is a possibility of damage or unsafe high voltage electrical system caused by the motor being dragged. Therefore, the market also expects to provide a hybrid electric drive device with a more complete limp home function and improved energy efficiency.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a hybrid electric driving device which has the advantages of good safety, high energy efficiency and wide application range.

In order to achieve the above object, the hybrid electric drive device of the present invention is as follows:

the hybrid electric drive device is mainly characterized by comprising an engine, a first motor, a second motor, a speed change mechanism, a first input shaft, a second input shaft, a third input shaft, an intermediate shaft, an output shaft, a rear transmission gear set, a first gear set, a second gear set and a third gear set, wherein the first motor is connected with the first input shaft, the second motor is connected with the second input shaft, the engine is connected with the third input shaft, and the intermediate shaft is connected with the output shaft through the rear transmission gear set; the first gear set is arranged between the first input shaft and the intermediate shaft, the second gear set is arranged between the second input shaft and the intermediate shaft, the third gear set is arranged between the third input shaft and the intermediate shaft, and the engine is connected with the third input shaft through the main clutch.

Preferably, the first input shaft, the second input shaft, the third input shaft and the output shaft are coaxially arranged, the first input shaft is arranged outside the second input shaft, and the second input shaft is arranged outside the third input shaft.

Preferably, the device further comprises a first shift element selectively engaging the first input shaft with the second input shaft and a second shift element selectively engaging the second input shaft with the third input shaft.

Preferably, the third gear set includes a first gear set, a reverse gear set and a third shifting element, the first gear set includes a first gear driving gear and a first gear driven gear, the reverse gear set includes a reverse gear driving gear, a reverse gear idler gear and a reverse gear driven gear, the first gear driving gear and the reverse gear driving gear are fixedly connected to the third input shaft, and the first gear driven gear and the reverse gear driven gear are freely sleeved on the intermediate shaft and selectively connected to the intermediate shaft through the third shifting element.

Preferably, the first gear set includes a second gear set, a third gear set and a fourth shifting element, the second gear set includes a second driving gear and a second driven gear, the third gear set includes a third driving gear and a third driven gear, the second driving gear and the third driving gear are fixedly connected to the first input shaft, and the second driven gear and the third driven gear are freely sleeved on the intermediate shaft and selectively connected with the intermediate shaft through the fourth shifting element.

Preferably, the second gear set includes a fourth gear set and a highest gear set, the fourth gear set includes a fourth gear driving gear and a fourth gear driven gear, the highest gear set includes a highest gear driving gear and a highest gear driven gear, the fourth gear driving gear is sleeved on the second input shaft in an empty manner and selectively communicated with the second input shaft through the first shifting element, the fourth gear driven gear is fixedly connected to the intermediate shaft, the highest gear driving gear is sleeved on the third input shaft in an empty manner and selectively communicated with the third input shaft through the second shifting element, and the highest gear driven gear is fixedly connected to the intermediate shaft.

Preferably, the second gear set further includes a fifth gear set, a sixth gear set and a fifth shifting element, the fifth gear set includes a fifth gear driving gear and a fifth gear driven gear, the sixth gear set includes a sixth gear driving gear and a sixth gear driven gear, the fifth gear driving gear and the sixth gear driving gear are fixedly connected to the second input shaft, and the fifth gear driven gear and the sixth gear driven gear are freely sleeved on the intermediate shaft and selectively connected to the intermediate shaft through the fifth shifting element.

With the hybrid electric drive of the present invention, the engine can utilize all gears while the first and second electric machines can utilize only some gears. When the vehicle runs at a low speed, the second shifting element and the third shifting element are in neutral, the first shifting element is in neutral or the first input shaft and the second input shaft are combined, the fourth shifting element is in second gear or third gear, the gear meshed with the third input shaft is not dragged, when the vehicle runs at a high speed, the third shifting element and the fourth shifting element are in neutral, the first shifting element and the second shifting element can selectively drive the engine at fourth gear or fifth gear, and the first motor and the gear meshed with the first input shaft are not dragged, so that internal dragging loss during running of the vehicle is reduced, and energy efficiency of an electric drive system is improved. When the high-voltage electrical system is in failure, the first shifting element and the second shifting element can be engaged in neutral gear, so that the first electric machine and the second electric machine are not dragged by the engine, and the engine can drive the vehicle to complete limp home, so that the hybrid electric drive device with complete limp home function and improved energy efficiency is obtained.

Drawings

Fig. 1 is a schematic structural view of an embodiment of the hybrid electric drive device of the present invention.

Fig. 2 is a schematic structural view of another embodiment of the hybrid electric drive device of the present invention.

Fig. 3 is a schematic view of a pure electric drive two-gear-suspension structure of a hybrid electric drive device according to a first embodiment of the present invention.

Fig. 4 is a structural schematic diagram of a pure electric drive two-gear and three-gear middle process of the hybrid electric drive device according to the first embodiment of the present invention.

Fig. 5 is a schematic diagram of a pure electric drive three-gear structure of the first embodiment of the hybrid electric drive device of the invention.

Reference numerals:

1 Engine

2 first electric machine

3 second electric machine

4 speed change mechanism

41 first input shaft

42 second input shaft

43 third input shaft

44 intermediate shaft

45 output shaft

46 rear drive gear set

47 first gear set

471 two-gear set

4711 two-gear driving gear

4712 two-gear driven gear

472 three speed gear set

4721 three-gear drive gear

4722 three-gear driven gear

473 fourth shift element

48 second gear set

481 four-gear set

4811 four-speed drive gear

4812 four-gear driven gear

482 highest gear gearset

4821 highest gear drive gear

4822 highest driven gear

483 five-gear set

4831 five-gear driving gear

4832 five-gear driven gear

484 six-gear set

4841 six-gear driving gear

4842 six-speed driven gear

485 fifth shift element

49 third gear gearset

491 one-gear set

4911 first gear drive gear

4912 first-gear driven gear

492 reverse gear set

4921 reverse gear drive gear

4922 reverse gear idler

4923 reverse driven gear

493 third shift element

51 first shifting element

52 second shifting element

Detailed Description

In order to more clearly describe the technical contents of the present invention, the following further description is given in conjunction with specific embodiments.

The hybrid electric drive device comprises an engine, a first motor, a second motor, a speed change mechanism, a first input shaft, a second input shaft, a third input shaft, an intermediate shaft, an output shaft, a rear transmission gear set, a first gear set, a second gear set and a third gear set, wherein the first motor is connected with the first input shaft, the second motor is connected with the second input shaft, the engine is connected with the third input shaft, and the intermediate shaft is connected with the output shaft through the rear transmission gear set; the first gear set is arranged between the first input shaft and the intermediate shaft, the second gear set is arranged between the second input shaft and the intermediate shaft, the third gear set is arranged between the third input shaft and the intermediate shaft, and the engine is connected with the third input shaft through the main clutch.

In a preferred embodiment of the present invention, the first input shaft, the second input shaft, the third input shaft, and the output shaft are coaxially disposed, the first input sleeve is disposed outside the second input shaft, and the second input sleeve is disposed outside the third input shaft.

In a preferred embodiment of the invention, the device further comprises a first shifting element for selectively connecting the first input shaft to the second input shaft and a second shifting element for selectively connecting the second input shaft to the third input shaft.

As a preferred embodiment of the present invention, the third gear set includes a first gear set, a reverse gear set and a third shifting element, the first gear set includes a first gear driving gear and a first gear driven gear, the reverse gear set includes a reverse gear driving gear, a reverse gear idler gear and a reverse gear driven gear, the first gear driving gear and the reverse gear driving gear are fixedly connected to the third input shaft, and the first gear driven gear and the reverse gear driven gear are freely sleeved on the intermediate shaft and selectively connected to the intermediate shaft through the third shifting element.

As a preferred embodiment of the present invention, the first gear set includes a second gear set, a third gear set and a fourth shifting element, the second gear set includes a second driving gear and a second driven gear, the third gear set includes a third driving gear and a third driven gear, the second driving gear and the third driving gear are fixedly connected to the first input shaft, and the second driven gear and the third driven gear are loosely sleeved on the intermediate shaft and selectively connected to the intermediate shaft through the fourth shifting element.

As a preferred embodiment of the present invention, the second gear set includes a fourth gear set and a highest gear set, the fourth gear set includes a fourth gear driving gear and a fourth gear driven gear, the highest gear set includes a highest gear driving gear and a highest gear driven gear, the fourth gear driving gear is idly sleeved on the second input shaft and selectively communicated with the second input shaft through the first shifting element, the fourth gear driven gear is fixedly connected to the intermediate shaft, the highest gear driving gear is idly sleeved on the third input shaft and selectively communicated with the third input shaft through the second shifting element, and the highest gear driven gear is fixedly connected to the intermediate shaft.

As a preferred embodiment of the present invention, the second gear set further includes a fifth gear set, a sixth gear set and a fifth shifting element, the fifth gear set includes a fifth gear driving gear and a fifth gear driven gear, the sixth gear set includes a sixth gear driving gear and a sixth gear driven gear, the fifth gear driving gear and the sixth gear driving gear are fixedly connected to the second input shaft, and the fifth gear driven gear and the sixth gear driven gear are freely sleeved on the intermediate shaft and selectively connected to the intermediate shaft through the fifth shifting element.

In an embodiment of the present invention, as shown in fig. 1, a hybrid electric drive device includes: an engine 1; a first electric machine 2; a second motor 3; the speed change mechanism 4 comprises a first input shaft 41, a second input shaft 42, a third input shaft 43, an intermediate shaft 44, an output shaft 45 and a rear transmission gear set 46, wherein the first motor 2 is connected with the first input shaft 41, the second motor 3 is connected with the second input shaft 42, the engine 1 is connected with the third input shaft 43, and the intermediate shaft 44 is connected with the output shaft 45 through the rear transmission gear set 46; a first gear gearset 47 arranged between first input shaft 41 and countershaft 44, a second gear gearset 48 arranged between second input shaft 42 and countershaft 44, a third gear gearset 49 arranged between third input shaft 43 and countershaft 44; the first shifting element 51 selectively connects the first input shaft 41 to the second input shaft 42, and the second shifting element 52 selectively connects the second input shaft 42 to the third input shaft 43.

The first motor, the second motor and the engine are respectively connected with the first input shaft, the second input shaft and the third input shaft, the first gear shifting element can selectively enable the first input shaft to be connected with the second input shaft, the second gear shifting element can selectively enable the second input shaft to be connected with the third input shaft, therefore, the engine can utilize all gears, the first motor and the second motor can only utilize partial gears, when a high-voltage electrical system fails, the first gear shifting element and the second gear shifting element can be in neutral gear engagement, the first motor and the second motor are not dragged by the engine, the engine can independently drive the vehicle to complete limp home, and therefore the hybrid electric drive device with the complete limp home function is obtained.

As shown in fig. 1, the first input shaft 41, the second input shaft 42, the third input shaft 43 and the output shaft 45 are coaxially arranged, the first input shaft 41 is sleeved on the outer side of the second input shaft 42, and the second input shaft 42 is sleeved on the outer side of the third input shaft 43. I.e. the three input shafts are arranged coaxially, and the output shaft is arranged coaxially therewith, which is advantageous for arranging the first shifting element 51 and the second shifting element 52 such that the three input shafts are switched on or off at the right moment.

As shown in fig. 1, the third gear gearset 49 includes a first gear gearset 491, a reverse gear gearset 492, and a third shifting element 493. The third gear gearset 49 may also be provided with more gearsets to meet the requirements of different vehicle types for speed change, and is not limited to this. The third input shaft 43 is connected to the engine 1, so that when limping home, the engine 1 can directly drive the two gearsets without power connection to the other input shaft, so as not to drive the two electric machines.

Specifically, the first gear set 491 includes a first gear driving gear 4911 and a first gear driven gear 4912, the reverse gear set 492 includes a reverse gear driving gear 4921, a reverse gear idler gear 4922 and a reverse gear driven gear 4923, the first gear driving gear 4911 and the reverse gear driving gear 4921 are fixedly connected to the third input shaft 43, the first gear driven gear 4912 and the reverse gear driven gear 4923 are loosely fitted on the countershaft 44 and selectively engaged with the countershaft 44 by the third shifting element 493.

As shown in fig. 1, first gear gearset 47 includes a two-gear gearset 471, a three-gear gearset 472, and a fourth shift element 473. That is, the first electric machine 2 directly drives the two gear sets, so that when the first shifting element 51 is disconnected, the vehicle can be driven by the first electric machine 2 to run, the second shifting element 52 enables the second input shaft 42 and the third input shaft 43 to be connected, and the engine 1 drives the second electric machine 3 to generate electricity, so that the series starting condition is realized. When both the first shifting element 51 and the second shifting element 52 are engaged, the power of the engine 1 can also be transmitted to the first input shaft 41, and the vehicle can be driven after shifting with the second gear set 471 or the third gear set 472. More gear sets are possible and can be selected as desired, without limitation.

Specifically, second gear set 471 includes a second gear drive gear 4711 and a second gear driven gear 4712, third gear set 472 includes a third gear drive gear 4721 and a third gear driven gear 4722, second gear drive gear 4711 and third gear drive gear 4721 are grounded to first input shaft 41, second gear driven gear 4712 and third gear driven gear 4722 are freely sleeved on countershaft 44 and selectively engageable with countershaft 44 via fourth shift element 473.

As shown in fig. 1, the second gear set 48 includes a fourth gear set 481 and a highest gear set 482. In the case of a shifting synchronizer or a shifting sleeve, the first shifting element 51 can realize either one of two gears, so that in order to fully utilize the characteristics of the device, a four-gear set 481 is provided which also uses the first shifting element 51 to realize shifting. Furthermore, a highest gear gearset 482 is also provided, which shifts with the second shifting element 52. Obviously, the highest gear in the gear shift mechanism 4 shown in fig. 1 is the fifth gear, and more gears are possible.

Specifically, the fourth-gear set 481 includes a fourth-gear driving gear 4811 and a fourth-gear driven gear 4812, the highest-gear set 482 includes a highest-gear driving gear 4821 and a highest-gear driven gear 4822, the fourth-gear driving gear 4811 is loosely sleeved on the second input shaft 42 and selectively communicated with the second input shaft 42 through the first shifting element 51, the fourth-gear driven gear 4812 is fixedly connected to the intermediate shaft 44, the highest-gear driving gear 4821 is loosely sleeved on the third input shaft 43 and selectively communicated with the third input shaft 43 through the second shifting element 52, and the highest-gear driven gear 4822 is fixedly connected to the intermediate shaft 44.

Fig. 2 is a schematic structural diagram of a hybrid electric drive device according to another embodiment of the present invention. As shown in fig. 2, the second gear set 48 also includes a fifth gear gearset 483, a sixth gear gearset 484, and a fifth shifting element 485.

Specifically, the fifth-gear set 483 includes a fifth-gear driving gear 4831 and a fifth-gear driven gear 4832, the sixth-gear set 484 includes a sixth-gear driving gear 4841 and a sixth-gear driven gear 4842, the fifth-gear driving gear 4831 and the sixth-gear driving gear 4841 are fixedly connected to the second input shaft 42, and the fifth-gear driven gear 4832 and the sixth-gear driven gear 4842 are loosely fitted on the counter shaft 44 and selectively engaged with the counter shaft 44 through the fifth shift element 485.

As shown in fig. 1, in the hybrid electric drive device, when the vehicle is driven normally, the first motor 2 and the second motor 3 can provide power at the second gear or the third gear selectively at the medium and low speeds, and the pure electric mode drive is performed, the engine 1 can provide power as a main power source at the fourth gear or the fifth gear selectively at the medium and high speeds, and the first motor 2 and the second motor 3 can be selectively used as a supplementary power source or generate power according to requirements, so that the engine works in a low oil consumption area most of the time, and the energy efficiency is improved.

In the hybrid electric drive device shown in fig. 1, the three power sources, i.e., the engine 1, the first electric machine 2 and the second electric machine 3, can realize power combination output in a superposition mode or output in a separate mode through the first gear shifting mechanism 51 and the second gear shifting mechanism 52, so that the output of a main output power source can be kept unchanged selectively during gear shifting, and the other power sources are shifted in high gears in advance to realize uninterrupted power during gear shifting. In the electric-only drive mode, the hybrid electric drive shown in fig. 1 shifts up to three gears in two, first in the 2-gear engaged state shown in fig. 3, the second shift element 52 and the third shift element 493 shift into neutral, the first shift element 51 can select neutral or connect the first input shaft 41 and the second input shaft 42 according to the load demand, and the fourth shift element 473 shifts up to two gears, while the vehicle keeps driving in two gears. When the upshift condition is met, the state shown in fig. 4 is that the second shift element 52 and the third shift element 493 are kept in neutral, the first shift element 51 is put into fourth gear, then the fourth shift element 473 is put back into neutral first and then put into third gear, then the first shift element 51 is put back into neutral or the first input shaft 41 and the second input shaft 42 are fixedly connected according to the load requirement, and at this time, the state shown in fig. 5 belongs to the state of 3 gears, and after the actions are completed, the second gear upshift is realized and the power of the whole process is not interrupted.

When the first shifting element 51 is in the fourth gear, the third shifting element 493 and the fourth shifting element 473 can be shifted into neutral, so that the first electric machine 2, which is not involved in driving at high vehicle speeds, is prevented from being dragged, thereby increasing the energy efficiency. When the second shift element 52 is shifted to connect the second input shaft 42 and the third input shaft 43, the engine 1 can drive the vehicle after shifting by the four-speed gear set 481.

When the second shifting element 52 is in the fifth gear, the first shifting element 51, the third shifting element 493 and the fourth shifting element 473 can be shifted into neutral, and the second electric machine 3 can also be prevented from being dragged like the first electric machine 2 without participating in driving the vehicle, thereby improving the energy efficiency at high vehicle speeds.

In the pure electric driving mode, the second shift element 52 is in the neutral gear, and the power of the engine 1 is not transmitted to the second input shaft 42, so that even if the engine 1 does not work, the clutch does not need to be separated, namely, the engine 1 is connected with the third input shaft 43 through the main clutch 6, and in the pure electric driving mode, the clutch does not need to be separated specially, and the normally closed main clutch 6 can also meet the requirement of the pure electric driving mode, and the problem of failure of elastic parts caused by long-term separation does not need to be considered.

With the hybrid electric drive of the present invention, the engine can utilize all gears while the first and second electric machines can utilize only some gears. When the vehicle runs at a low speed, the second shifting element and the third shifting element are in neutral, the first shifting element is in neutral or the first input shaft and the second input shaft are combined, the fourth shifting element is in second gear or third gear, the gear meshed with the third input shaft is not dragged, when the vehicle runs at a high speed, the third shifting element and the fourth shifting element are in neutral, the first shifting element and the second shifting element can selectively drive the engine at fourth gear or fifth gear, and the first motor and the gear meshed with the first input shaft are not dragged, so that internal dragging loss during running of the vehicle is reduced, and energy efficiency of an electric drive system is improved. When the high-voltage electrical system is in failure, the first shifting element and the second shifting element can be engaged in neutral gear, so that the first electric machine and the second electric machine are not dragged by the engine, and the engine can drive the vehicle to complete limp home, so that the hybrid electric drive device with complete limp home function and improved energy efficiency is obtained.

In this specification, the invention has been described with reference to specific embodiments thereof. It will, however, be evident that various modifications and changes may be made thereto without departing from the broader spirit and scope of the invention. The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense.