阅读说明：本技术 一种三电机三中间轴多挡变速系统 (Three-motor three-intermediate-shaft multi-gear speed change system ) 是由 郝庆军 冯涛 王琳 陆中华 朱学军 于 2021-08-25 设计创作，主要内容包括：本发明提供一种三电机三中间轴多挡变速系统,其特征在于：所述变速系统包括：第一电机；第二电机；第三电机；第一输入轴；第一中间轴；第二输入轴；第二中间轴；第三输入轴；第三中间轴；输出轴；第一离合器；第二离合器；第三离合器；第四离合器；第五离合器；第六离合器；通过6离合器共同作用,实现7种工作模式,变速范围大,适用范围广；通过设置有多根中间轴,变速齿轮均布于各中间轴上,实现多挡变速的同时,有效缩短轴向距离,提升功率密度；所需变速箱档位齿轮种类减少；在相同条件下,单个电机输入扭矩降低,电机转速可更高,可更大地减小电机尺寸,进一步简化内部结构空间。(The invention provides a three-motor three-intermediate-shaft multi-gear speed change system which is characterized in that: the transmission system includes: a first motor; a second motor; a third motor; a first input shaft; a first intermediate shaft; a second input shaft; a second intermediate shaft; a third input shaft; a third intermediate shaft; an output shaft; a first clutch; a second clutch; a third clutch; a fourth clutch; a fifth clutch; a sixth clutch; 7 working modes are realized through the combined action of the 6 clutches, the speed change range is large, and the application range is wide; by arranging the plurality of intermediate shafts and uniformly distributing the speed change gears on the intermediate shafts, the axial distance is effectively shortened and the power density is improved while multi-gear speed change is realized; the variety of gears of the gear box required is reduced; under the same condition, the input torque of a single motor is reduced, the rotating speed of the motor can be higher, the size of the motor can be reduced greatly, and the internal structural space is further simplified.)

1. The utility model provides a three motor three jackshafts multispeed variable speed system which characterized in that: the transmission system includes:

a first electric machine (EM 1);

a second electric machine (EM 2);

a third electric machine (EM 3);

the output shaft (1-1) of the first motor is connected with the first intermediate shaft (1-2) through a first reduction transmission pair; a first motor first input driving gear (Z11), a first motor second input driving gear (Z12) and a first motor third input driving gear (Z13) are arranged on the first intermediate shaft (1-2);

the output shaft (2-1) of the second motor is connected with the second intermediate shaft (2-2) through a second reduction transmission pair; a second motor first input driving gear (Z21), a second motor second input driving gear (Z22) and a second motor third input driving gear (Z23) are arranged on the second intermediate shaft (2-2);

the output shaft (3-1) of the third motor is connected with a third intermediate shaft (3-2) through a third reduction transmission pair; a third motor first input driving gear (Z31), a third motor second input driving gear (Z32) and a third motor third input driving gear (Z33) are arranged on the third intermediate shaft (3-2);

a transmission output shaft (4), the transmission output shaft (4) being provided with a first output driven gear (Z41), a second output driven gear (Z42), and a third output driven gear (Z43);

it is characterized in that the preparation method is characterized in that,

the first motor output shaft (1-1), the second motor output shaft (2-1), the third motor output shaft (3-1), the first intermediate shaft (1-2), the second intermediate shaft (2-2), the third intermediate shaft (3-2) and the speed change system output shaft (4) are arranged in parallel, and the first intermediate shaft, the second intermediate shaft and the third intermediate shaft are arranged on the periphery of the speed change system output shaft (4) in a surrounding mode.

2. A three-motor, three-intermediate-shaft, multi-speed transmission system according to claim 1, wherein: the first output driven gear (Z41) is meshed with a first motor first input driving gear (Z11), a second motor first input driving gear (Z21) and a third motor first input driving gear (Z31); the second output driven gear (Z42) is meshed with a second input driving gear (Z12) of the first motor, a second input driving gear (Z22) of the second motor and a second input driving gear (Z32) of the third motor; the third output driven gear (Z43) is engaged with the first motor third input driving gear (Z13), the second motor third input driving gear (Z23) and the third motor third input driving gear (Z33).

3. A three-motor, three-intermediate-shaft, multi-speed transmission system according to claim 2, wherein: the transmission system further includes:

a first clutch (A) disposed on the first intermediate shaft (1-2) between the first motor first input drive gear (Z11) and the first motor second input drive gear (Z12) for selectively engaging therewith;

a second clutch (B) disposed on the first intermediate shaft (1-2) and located on one side of the first motor third input drive gear (Z13) for selective engagement therewith;

a third clutch (C) disposed on the second intermediate shaft (2-2) between the second motor first input drive gear (Z21) and the second motor second input drive gear (Z22) for selectively engaging therewith;

a fourth clutch (D) disposed on the second intermediate shaft (2-2) on one side of a second motor third input drive gear (Z23) to be selectively engageable therewith;

a fifth clutch (E) disposed on said third intermediate shaft (3-2) and located between the third motor first input driving gear (Z31) and the third motor second input driving gear (Z32) for selectively engaging therewith;

a sixth clutch (F) disposed on the third countershaft (3-2) on one side of the third motor third input drive gear (Z33) for selective engagement therewith.

4. A three motor, three intermediate shaft, multiple speed transmission system according to any one of claims 1 to 3, wherein: the first, second and third intermediate shafts are arranged around the periphery of the output shaft (4) of the speed change system at equal intervals in a manner of being 120 degrees apart from each other.

5. A three motor, three intermediate shaft, multiple speed transmission system according to any one of claims 1 to 3, wherein: the first reduction transmission pair comprises a first transmission driving gear (Z1) and a first transmission driven gear (Z10) which are meshed with each other, the first transmission driving gear (Z1) is arranged on the first motor output shaft (1-1), and the first transmission driven gear (Z10) is arranged on the first intermediate shaft (1-2);

the second reduction transmission pair comprises a second transmission driving gear (Z2) and a second transmission driven gear (Z20) which are meshed with each other, the second transmission driving gear (Z2) is arranged on the second motor output shaft (2-1), and the second transmission driven gear (Z20) is arranged on the second intermediate shaft (2-2);

the third reduction transmission pair comprises a third transmission driving gear (Z3) and a third transmission driven gear (Z30) which are meshed with each other, the third transmission driving gear (Z3) is arranged on the third motor output shaft (3-1), and the third transmission driven gear (Z30) is arranged on the third intermediate shaft (3-2).

6. A three-motor, three-intermediate-shaft, multi-speed transmission system according to claim 5, wherein: on the first intermediate shaft (1-2), a first transmission driven gear (Z10), a first motor first input driving gear (Z11), a first motor second input driving gear (Z12) and a first motor third input driving gear (Z13) are sequentially arranged from the direction close to the first motor (EM 1) to the direction far away from the first motor (EM 1).

7. A three-motor, three-intermediate-shaft, multi-speed transmission system according to claim 5, wherein: and a second transmission driven gear (Z20), a second motor first input driving gear (Z21), a second motor second input driving gear (Z22) and a second motor third input driving gear (Z23) are sequentially arranged on the second intermediate shaft (2-2) from the direction close to the second motor (EM 2) to the direction far away from the second motor (EM 2).

8. A three-motor, three-intermediate-shaft, multi-speed transmission system according to claim 5, wherein: and a third transmission driven gear (Z30), a third motor first input driving gear (Z31), a third motor second input driving gear (Z32) and a third motor third input driving gear (Z33) are sequentially arranged on the third intermediate shaft (3-2) from the direction close to the third motor (EM 3) to the direction far away from the third motor (EM 3).

9. A three-motor, three-intermediate-shaft, multi-speed transmission system according to claim 5, wherein: a first output driven gear (Z41), a second output driven gear (Z42) and a third output driven gear (Z43) are sequentially arranged on the output shaft (4) of the speed changing system from the direction close to the first motor, the direction close to the second motor and the direction far from the third motor, the direction far from the second motor and the direction far from the third motor.

10. A method of shifting a three motor, three countershaft multiple speed transmission according to any one of claims 1-9 wherein: the multi-gear speed change system is provided with an electric control unit, and the electric control unit predicts the load condition of the current system according to the current torque demand, the motor rotating speed and the opening information of an accelerator pedal;

if it is determined that the upshift action can be performed,

in the shifting process of shifting from the 1 st gear to the 2 nd gear and from the 4 th gear to the 5 th gear, controlling the torque of the second driving motor (EM 2) to be reduced until a gear disengaging action is carried out, simultaneously driving the first driving motor (EM 1) and the third driving motor (EM 3) to increase the torque, after the second driving motor (EM 2) is shifted, recovering the driving torque of the second driving motor (EM 2), and simultaneously controlling the first driving motor (EM 1) and the third driving motor (EM 3) to reduce the torque;

in the shifting process of shifting from the 2 nd gear to the 3 rd gear and shifting from the 5 th gear to the 6 th gear, controlling the torque of the first driving motor (EM 1) to be reduced until a gear disengaging action is carried out, simultaneously driving the second driving motor (EM 2) and the third driving motor (EM 3) to increase the torque, after the shifting of the first driving motor (EM 1) is completed, recovering the driving torque of the first driving motor (EM 1), and simultaneously controlling the second driving motor (EM 2) and the third driving motor (EM 3) to reduce the torque;

in the shifting process of shifting from the 3 rd gear to the 4 th gear and shifting from the 6 th gear to the 7 th gear, controlling the torque of the third driving motor (EM 3) to be reduced until a gear disengaging action is carried out, simultaneously driving the first driving motor (EM 1) and the second driving motor (EM 2) to increase the torque, after the shifting of the third driving motor (EM 3) is completed, recovering the driving torque of the third driving motor (EM 3), and simultaneously controlling the first driving motor (EM 1) and the second driving motor (EM 2) to reduce the torque;

if it is determined that the downshift action can be performed,

in the shifting process of shifting from the 2 nd gear to the 1 st gear and from the 5 th gear to the 4 th gear, controlling the torque of the second driving motor (EM 2) to be reduced until a gear disengaging action is carried out, simultaneously driving the first driving motor (EM 1) and the third driving motor (EM 3) to increase the torque, after the second driving motor (EM 2) is shifted, recovering the driving torque of the second driving motor (EM 2), and simultaneously controlling the first driving motor (EM 1) and the third driving motor (EM 3) to reduce the torque;

in the shifting process of shifting from the 3 rd gear to the 2 nd gear and shifting from the 6 th gear to the 5 th gear, controlling the torque of the first driving motor (EM 1) to be reduced until a gear disengaging action is carried out, simultaneously driving the second driving motor (EM 2) and the third driving motor (EM 3) to increase the torque, after the shifting of the first driving motor (EM 1) is completed, recovering the driving torque of the first driving motor (EM 1), and simultaneously controlling the second driving motor (EM 2) and the third driving motor (EM 3) to reduce the torque;

in the shifting process of shifting from the 4 th gear to the 3 rd gear and shifting from the 7 th gear to the 6 th gear, controlling the torque of the third driving motor (EM 3) to be reduced until a gear disengaging action is carried out, simultaneously driving the first driving motor (EM 1) and the second driving motor (EM 2) to increase the torque, after the shifting of the third driving motor (EM 3) is completed, recovering the driving torque of the third driving motor (EM 3), and simultaneously controlling the first driving motor (EM 1) and the second driving motor (EM 2) to reduce the torque;

when the vehicle is parked, the electronic control unit controls corresponding gear shifting mechanisms close to the first driving motor (EM 1), the second driving motor (EM 2) and the third driving motor (EM 3) to act simultaneously, and the gear is shifted back to the neutral gear.

Technical Field

The invention relates to the technical field of vehicle speed change systems, in particular to a three-motor three-intermediate-shaft multi-gear speed change system.

Background

In current vehicle speed change system, the transmission mode of many jackshafts of many driving sources has been proposed to different operating modes, wherein more often adopt for the arrangement mode of many jackshafts of bi-motor, however in current bi-motor bi-jackshaft transmission system, the moment of torsion that the jackshaft receives is great, and output torque is less, and the jackshaft tooth axle life-span is low, and power density is little, and simultaneously for realizing the transmission of keeping off more, the epaxial gear number of every transmission is more, and axial dimension is great, and occupation space is big.

Disclosure of Invention

In order to solve the defects in the prior art, the invention provides a three-motor three-intermediate-shaft multi-gear speed change system.

The technical scheme provided by the invention is as follows: the utility model provides a three motor three jackshafts multispeed variable speed system which characterized in that: the transmission system includes:

a first electric machine (EM 1);

a second electric machine (EM 2);

a third electric machine (EM 3);

the output shaft (1-1) of the first motor is connected with the first intermediate shaft (1-2) through a first reduction transmission pair; a first motor first input driving gear (Z11), a first motor second input driving gear (Z12) and a first motor third input driving gear (Z13) are arranged on the first intermediate shaft (1-2);

the output shaft (2-1) of the second motor is connected with the second intermediate shaft (2-2) through a second reduction transmission pair; a second motor first input driving gear (Z21), a second motor second input driving gear (Z22) and a second motor third input driving gear (Z23) are arranged on the second intermediate shaft (2-2);

the output shaft (3-1) of the third motor is connected with a third intermediate shaft (3-2) through a third reduction transmission pair; a third motor first input driving gear (Z31), a third motor second input driving gear (Z32) and a third motor third input driving gear (Z33) are arranged on the third intermediate shaft (3-2);

a transmission output shaft (4), the transmission output shaft (4) being provided with a first output driven gear (Z41), a second output driven gear (Z42), and a third output driven gear (Z43);

the first motor output shaft (1-1), the second motor output shaft (2-1), the third motor output shaft (3-1), the first intermediate shaft (1-2), the second intermediate shaft (2-2), the third intermediate shaft (3-2) and the speed change system output shaft (4) are arranged in parallel, and the first intermediate shaft, the second intermediate shaft and the third intermediate shaft are arranged on the periphery of the speed change system output shaft (4) in a surrounding mode.

Further, the first output driven gear (Z41) is meshed with the first motor first input driving gear (Z11), the second motor first input driving gear (Z21) and the third motor first input driving gear (Z31); the second output driven gear (Z42) is meshed with a second input driving gear (Z12) of the first motor, a second input driving gear (Z22) of the second motor and a second input driving gear (Z32) of the third motor; the third output driven gear (Z43) is engaged with the first motor third input driving gear (Z13), the second motor third input driving gear (Z23) and the third motor third input driving gear (Z33).

Further, the transmission system further includes:

a first clutch (A) disposed on the first intermediate shaft (1-2) between the first motor first input drive gear (Z11) and the first motor second input drive gear (Z12) for selectively engaging therewith;

a second clutch (B) disposed on the first intermediate shaft (1-2) and located on one side of the first motor third input drive gear (Z13) for selective engagement therewith;

a third clutch (C) disposed on the second intermediate shaft (2-2) between the second motor first input drive gear (Z21) and the second motor second input drive gear (Z22) for selectively engaging therewith;

a fourth clutch (D) disposed on the second intermediate shaft (2-2) on one side of a second motor third input drive gear (Z23) to be selectively engageable therewith;

a fifth clutch (E) disposed on said third intermediate shaft (3-2) and located between the third motor first input driving gear (Z31) and the third motor second input driving gear (Z32) for selectively engaging therewith;

a sixth clutch (F) disposed on the third countershaft (3-2) on one side of the third motor third input drive gear (Z33) for selective engagement therewith.

Furthermore, the first, second and third intermediate shafts are arranged around the periphery of the output shaft (4) of the speed change system at equal intervals in a manner of being 120 degrees apart from each other.

5. A three motor, three intermediate shaft, multiple speed transmission system according to any one of claims 1 to 3, wherein: the first reduction transmission pair comprises a first transmission driving gear (Z1) and a first transmission driven gear (Z10) which are meshed with each other, the first transmission driving gear (Z1) is arranged on the first motor output shaft (1-1), and the first transmission driven gear (Z10) is arranged on the first intermediate shaft (1-2);

the second reduction transmission pair comprises a second transmission driving gear (Z2) and a second transmission driven gear (Z20) which are meshed with each other, the second transmission driving gear (Z2) is arranged on the second motor output shaft (2-1), and the second transmission driven gear (Z20) is arranged on the second intermediate shaft (2-2);

the third reduction transmission pair comprises a third transmission driving gear (Z3) and a third transmission driven gear (Z30) which are meshed with each other, the third transmission driving gear (Z3) is arranged on the third motor output shaft (3-1), and the third transmission driven gear (Z30) is arranged on the third intermediate shaft (3-2).

Furthermore, a first transmission driven gear (Z10), a first motor first input driving gear (Z11), a first motor second input driving gear (Z12) and a first motor third input driving gear (Z13) are sequentially arranged on the first intermediate shaft (1-2) from the direction close to the first motor (EM 1) to the direction far away from the first motor (EM 1).

Furthermore, a second transmission driven gear (Z20), a second motor first input driving gear (Z21), a second motor second input driving gear (Z22) and a second motor third input driving gear (Z23) are sequentially arranged on the second intermediate shaft (2-2) from the direction close to the second motor (EM 2) to the direction far away from the second motor (EM 2).

Furthermore, a third transmission driven gear (Z30), a third motor first input driving gear (Z31), a third motor second input driving gear (Z32) and a third motor third input driving gear (Z33) are sequentially arranged on the third intermediate shaft (3-2) from the direction close to the third motor (EM 3) to the direction far away from the third motor (EM 3).

Further, a first output driven gear (Z41), a second output driven gear (Z42) and a third output driven gear (Z43) are sequentially arranged on the output shaft (4) of the speed change system from the direction close to the first motor, the direction close to the second motor and the direction far from the third motor.

The multi-gear speed change system is provided with an electric control unit which predicts the load condition of the current system according to the current torque demand, the motor rotating speed and the opening information of an accelerator pedal;

if it is determined that the upshift action can be performed,

in the shifting process of shifting from the 1 st gear to the 2 nd gear and from the 5 th gear to the 6 th gear, controlling the torque of the second driving motor (EM 2) to be reduced until a gear disengaging action is carried out, simultaneously driving the first driving motor (EM 1) and the third driving motor (EM 3) to increase the torque, after the second driving motor (EM 2) is shifted, recovering the driving torque of the second driving motor (EM 2), and simultaneously controlling the first driving motor (EM 1) and the third driving motor (EM 3) to reduce the torque;

in the shifting process of shifting from the 2 nd gear to the 3 rd gear and shifting from the 5 th gear to the 6 th gear, controlling the torque of the first driving motor (EM 1) to be reduced until a gear disengaging action is carried out, simultaneously driving the second driving motor (EM 2) and the third driving motor (EM 3) to increase the torque, after the shifting of the first driving motor (EM 1) is completed, recovering the driving torque of the first driving motor (EM 1), and simultaneously controlling the second driving motor (EM 2) and the third driving motor (EM 3) to reduce the torque;

in the shifting process of shifting from the 3 rd gear to the 4 th gear and shifting from the 6 th gear to the 7 th gear, controlling the torque of the third driving motor (EM 3) to be reduced until a gear disengaging action is carried out, simultaneously driving the first driving motor (EM 1) and the second driving motor (EM 2) to increase the torque, after the shifting of the third driving motor (EM 3) is completed, recovering the driving torque of the third driving motor (EM 3), and simultaneously controlling the first driving motor (EM 1) and the second driving motor (EM 2) to reduce the torque;

if it is determined that the downshift action can be performed,

in the shifting process of shifting from the 2 nd gear to the 1 st gear and from the 5 th gear to the 4 th gear, controlling the torque of the second driving motor (EM 2) to be reduced until a gear disengaging action is carried out, simultaneously driving the first driving motor (EM 1) and the third driving motor (EM 3) to increase the torque, after the second driving motor (EM 2) is shifted, recovering the driving torque of the second driving motor (EM 2), and simultaneously controlling the first driving motor (EM 1) and the third driving motor (EM 3) to reduce the torque;

in the shifting process of shifting from the 3 rd gear to the 2 nd gear and shifting from the 6 th gear to the 5 th gear, controlling the torque of the first driving motor (EM 1) to be reduced until a gear disengaging action is carried out, simultaneously driving the second driving motor (EM 2) and the third driving motor (EM 3) to increase the torque, after the shifting of the first driving motor (EM 1) is completed, recovering the driving torque of the first driving motor (EM 1), and simultaneously controlling the second driving motor (EM 2) and the third driving motor (EM 3) to reduce the torque;

in the shifting process of shifting from the 4 th gear to the 3 rd gear and shifting from the 7 th gear to the 6 th gear, controlling the torque of the third driving motor (EM 3) to be reduced until a gear disengaging action is carried out, simultaneously driving the first driving motor (EM 1) and the second driving motor (EM 2) to increase the torque, after the shifting of the third driving motor (EM 3) is completed, recovering the driving torque of the third driving motor (EM 3), and simultaneously controlling the first driving motor (EM 1) and the second driving motor (EM 2) to reduce the torque;

when the vehicle is parked, the electronic control unit controls corresponding gear shifting mechanisms close to the first driving motor (EM 1), the second driving motor (EM 2) and the third driving motor (EM 3) to act simultaneously, and the gear is shifted back to the neutral gear.

Compared with the prior art, the invention has the following beneficial effects:

1) the invention provides a three-motor three-intermediate-shaft multi-gear speed change system, which changes the number of intermediate shafts in the prior art from 2 to 3 or more, effectively prolongs the service life of intermediate shaft gear shafts, increases the power density, reduces the size of a box body occupied by the intermediate shaft gear shafts, and realizes unpowered interruption in the whole gear shifting process.

2) The invention provides a three-motor three-intermediate-shaft multi-gear speed change system 3 pair of gears, which realizes 7 working modes through the combined action of 6 clutches, and has the advantages of large speed change range and wide application range.

3) The invention provides a three-motor three-intermediate-shaft multi-gear speed change system 3 pair of gears, which is provided with a plurality of intermediate shafts, and speed change gears are uniformly distributed on the intermediate shafts, so that multi-gear speed change is realized, the axial distance is effectively shortened, and the power density is improved.

4) The invention provides a three-motor three-intermediate-shaft multi-gear speed change system, which realizes multi-gear speed change and reduces the types of gears of a gear box required at the same time because the number of intermediate shafts is large.

5) The invention provides a three-motor three-intermediate-shaft multi-gear speed change system, which has the advantages that under the same condition, the input torque of a single motor is reduced, the rotating speed of the motor can be higher, the size of the motor can be greatly reduced, and the internal structure space is further simplified.

Drawings

Fig. 1 is a schematic structural diagram of a three-motor three-intermediate-shaft multi-gear speed change system.

Fig. 2 is a structural side view of a three-motor three-intermediate-shaft multi-gear speed change system.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "upper", "lower", "inner", "outer", "front", "rear", "both ends", "one end", "the other end", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "disposed," "connected," and the like are to be construed broadly, such as "connected," which may be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

In order to solve the defects in the prior art, the technical scheme provided by the invention is as follows:

a three-motor, three-countershaft, multiple speed transmission system comprising:

a first electric machine EM 1; a second electric machine EM 2; a third electric machine EM 3.

The first input shaft 1-1 is fixedly connected with an output shaft of the first electric motor EM1, and a first transmission driving gear Z1 is fixedly arranged on the first input shaft 1-1.

The transmission mechanism comprises a first intermediate shaft 1-2, wherein a first transmission driven gear Z10 meshed with a first transmission driving gear Z1 is fixedly arranged on the first intermediate shaft 1-2, and a first motor first input driving gear Z11, a first motor second input driving gear Z12 and a first motor third input driving gear Z13 are further arranged on the first intermediate shaft 1-2.

The second input shaft 2-1 is fixedly connected with an output shaft of the second electric motor EM2, and a second transmission driving gear Z2 is fixedly arranged on the second input shaft 2-1.

The transmission mechanism comprises a second intermediate shaft 2-2, wherein a second transmission driven gear Z20 meshed with a second transmission driving gear Z2 is fixedly arranged on the second intermediate shaft 2-2, and a second motor first input driving gear Z21, a second motor second input driving gear Z22 and a second motor third input driving gear Z23 are further arranged on the second intermediate shaft 2-2.

And the third input shaft 3-1 is fixedly connected with an output shaft of the third electric motor EM3, and a third transmission driving gear Z3 is fixedly arranged on the third input shaft 3-1.

The third countershaft 3-2 is fixedly provided with a third transmission driven gear Z30 meshed with a third transmission driving gear Z3, and the third countershaft 3-2 is further provided with a third motor first input driving gear Z31, a third motor second input driving gear Z32 and a third motor third input driving gear Z33.

A transmission system output shaft 4, on which a first output driven gear Z41, a second output driven gear Z42, and a third output driven gear Z43 are fixedly provided; the first output driven gear Z41 is meshed with a first motor first input driving gear Z11, a second motor first input driving gear Z21 and a third motor first input driving gear Z31, the second output driven gear Z42 is meshed with a first motor second input driving gear Z12, a second motor second input driving gear Z22 and a third motor second input driving gear Z32, and the third output driven gear Z43 is meshed with a first motor third input driving gear Z13, a second motor third input driving gear Z23 and a third motor third input driving gear Z33.

The first, second and third input shafts, the first, second and third intermediate shafts and the output shaft are arranged in parallel, and the first, second and third intermediate shafts are arranged around the outer circumference of the output shaft (see fig. 2).

A first clutch a disposed on the first countershaft 1-2 between the first motor first input drive gear Z11 and the first motor second input drive gear Z12 for selectively engaging therewith.

A second clutch B disposed on the first intermediate shaft 1-2 on one side of the first motor third input drive gear Z13 for selective engagement therewith;

a third clutch C disposed on the second intermediate shaft 2-2 between the second motor first input driving gear Z21 and the second motor second input driving gear Z22 for selectively engaging therewith;

a fourth clutch D provided on the second intermediate shaft 2-2 at one side of the second motor third input driving gear Z23 to be selectively engaged therewith;

a fifth clutch E disposed on the third intermediate shaft 3-2 between the third motor first input drive gear Z31 and the third motor second input drive gear Z32 for selectively engaging therewith;

a sixth clutch F disposed on the third intermediate shaft 3-2 on one side of the third motor third input drive gear Z33 for selective engagement therewith.

Specifically, the first, second and third countershafts are arranged around the periphery of the output shaft at equal intervals at 120 degrees intervals, so that the arrangement of the gear shifting gears on the countershafts is balanced, and the internal structure is further simplified (see fig. 2).

Specifically, the first clutch, the second clutch, the third clutch, the fourth clutch, the fifth clutch and the sixth clutch are dog-type gear shifting clutches, so that gear shifting response is timely, and gear shifting is safe and reliable.

Specifically, a first transmission driven gear Z10, a first motor first input driving gear Z11, a first motor second input driving gear Z12 and a first motor third input driving gear Z13 are sequentially disposed on the first countershaft 1-2 from a position close to the first electric motor EM1 to a position away from the first electric motor EM 1.

Specifically, a second transmission driven gear Z20, a second motor first input driving gear Z21, a second motor second input driving gear Z22 and a second motor third input driving gear Z23 are sequentially disposed on the second intermediate shaft 2-2 from a direction close to the second electric motor EM2 to a direction away from the second electric motor EM 2.

Specifically, a third transmission driven gear Z30, a third motor first input driving gear Z31, a third motor second input driving gear Z32 and a third motor third input driving gear Z33 are sequentially disposed on the third intermediate shaft 3-2 from a position close to the third electric motor EM3 to a position far from the third electric motor EM 3.

Specifically, a first output driven gear Z41, a second output driven gear Z42, and a third output driven gear Z43 are provided in this order on the transmission output shaft 4 from the direction close to the first, second, and third motors to the direction away from the first, second, and third motors.

The invention further provides a gear shifting method of the three-motor three-intermediate-shaft multi-gear speed changing system, wherein the multi-gear speed changing system is provided with an electric control unit, and the electric control unit predicts the load condition of the current system according to the current torque demand, the motor rotating speed and the opening degree information of an accelerator pedal;

if it is determined that the upshift action can be performed,

in the shifting process of shifting from the 1 st gear to the 2 nd gear and from the 4 th gear to the 5 th gear, controlling the torque of the second driving motor EM2 to be reduced until a gear disengaging action is carried out, simultaneously driving the first driving motor EM1 and the third driving motor EM3 to increase the torque, after the gear shifting of the second driving motor EM2 is completed, recovering the driving torque of the second driving motor EM2, and simultaneously controlling the first driving motor EM1 and the third driving motor EM3 to reduce the torque;

in the shifting process of shifting from the 2 nd gear to the 3 rd gear and from the 5 th gear to the 6 th gear, controlling the torque of the first driving motor EM1 to be reduced until a gear disengaging action is carried out, simultaneously driving the second driving motor EM2 and the third driving motor EM3 to increase the torque, after the shifting of the first driving motor EM1 is completed, recovering the driving torque of the first driving motor EM1, and simultaneously controlling the second driving motor EM2 and the third driving motor EM3 to reduce the torque;

in the shifting process of shifting from the 3 rd gear to the 4 th gear and from the 6 th gear to the 7 th gear, controlling the torque of the third driving motor EM3 to be reduced until a gear disengaging action is carried out, simultaneously driving the first driving motor EM1 and the second driving motor EM2 to increase the torque, after the shifting of the third driving motor EM3 is completed, recovering the driving torque of the third driving motor EM3, and simultaneously controlling the first driving motor EM1 and the second driving motor EM2 to reduce the torque;

if it is determined that the downshift action can be performed,

in the shifting process of shifting the 2 nd gear to the 1 st gear and shifting the 5 th gear to the 4 th gear, controlling the torque of the second driving motor EM2 to be reduced until a gear disengaging action is carried out, simultaneously driving the first driving motor EM1 and the third driving motor EM3 to increase the torque, after the gear shifting of the second driving motor EM2 is completed, recovering the driving torque of the second driving motor EM2, and simultaneously controlling the first driving motor EM1 and the third driving motor EM3 to reduce the torque;

in the shifting process of shifting from the 3 rd gear to the 2 nd gear and from the 6 th gear to the 5 th gear, controlling the torque of the first driving motor EM1 to be reduced until a gear disengaging action is carried out, simultaneously driving the second driving motor EM2 and the third driving motor EM3 to increase the torque, after the shifting of the first driving motor EM1 is completed, recovering the driving torque of the first driving motor EM1, and simultaneously controlling the second driving motor EM2 and the third driving motor EM3 to reduce the torque;

in the shifting process of shifting from the 4 th gear to the 3 rd gear and from the 7 th gear to the 6 th gear, controlling the torque of the third driving motor EM3 to be reduced until a gear disengaging action is carried out, simultaneously driving the first driving motor EM1 and the second driving motor EM2 to increase the torque, after the shifting of the third driving motor EM3 is completed, recovering the driving torque of the third driving motor EM3, and simultaneously controlling the first driving motor EM1 and the second driving motor EM2 to reduce the torque;

when the vehicle is parked, the electronic control unit controls corresponding shifting mechanisms close to the first driving motor EM1, the second driving motor EM2 and the third driving motor EM3 to act simultaneously, and the vehicle is shifted back to the neutral gear.

The working conditions of all clutches in different gear working conditions of the system are as follows (as shown in table 1):

TABLE 1 operating condition table of each clutch in different gear operating conditions of the system

Note: and v represents the operating position of each clutch under the current operating condition.

In the N gear, the first clutch A is centered, the second clutch B is not engaged, the third clutch C is centered, the fourth clutch D is not engaged, the fifth clutch E is centered, and the sixth clutch F is not engaged;

in the 1 gear, the first clutch A is engaged on the left, the second clutch B is not engaged, the third clutch C is engaged on the left, the fourth clutch D is not engaged, the fifth clutch E is engaged on the left, and the sixth clutch F is not engaged;

in the gear 2, the first clutch A is engaged on the left, the second clutch B is not engaged, the third clutch C is engaged on the right, the fourth clutch D is not engaged, the fifth clutch E is engaged on the left, and the sixth clutch F is not engaged;

in the 3-gear stage, the first clutch A is engaged on the right, the second clutch B is not engaged, the third clutch C is engaged on the right, the fourth clutch D is not engaged, the fifth clutch E is engaged on the left, and the sixth clutch F is not engaged;

in the 4-gear stage, the first clutch A is engaged to the right, the second clutch B is not engaged, the third clutch C is engaged to the right, the fourth clutch D is not engaged, the fifth clutch E is engaged to the right, and the sixth clutch F is not engaged;

in the gear 5, the first clutch A is engaged to the right, the second clutch B is not engaged, the third clutch C is centered, the fourth clutch D is engaged to the left, the fifth clutch E is engaged to the right, and the sixth clutch F is not engaged;

in the 6-gear, the first clutch A is in the middle, the second clutch B is engaged on the left, the third clutch C is in the middle, the fourth clutch D is engaged on the left, the fifth clutch E is engaged on the right, and the sixth clutch F is not engaged;

in gear 7, the first clutch a is centered, the second clutch B is engaged to the left, the third clutch C is centered, the fourth clutch D is engaged to the left, the fifth clutch E is centered, and the sixth clutch F is engaged to the left.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.