Dual-motor drive system and vehicle

Abstract

A dual-motor drive system, comprising a main drive motor (10), an auxiliary drive motor (11), and a speed reducer (12). The main drive motor is a synchronous motor, and the auxiliary drive motor is an asynchronous motor; when the main drive motor (10) independently operates, the auxiliary drive motor (11) does not generate back electromotive force, so that there is no additional energy loss; the two drive motors correspond to different reduction ratios, and the reduction ratio of the main drive motor (10) is less than that of the auxiliary drive motor. The main drive motor is mainly used for a high-speed drive working condition, and selection of a small reduction ratio allows working condition points to be distributed within a high-efficiency range of the motor; and the auxiliary drive motor is mainly used for a climbing working condition and an acceleration working condition, and selection of a large reduction ratio can obtain greater climbing torque and acceleration, thereby improving the driving efficiency of the system, and reducing energy consumption. An output shaft of each drive motor is integrated with a corresponding input shaft of the speed reducer, thereby achieving high transmission precision of the system, improving the structural strength of the system, and reducing the weight and the size of the system. Also provided is a vehicle comprising the motor drive system.

Description

A dual-motor drive system and vehicle Technical Field

[0001] This invention relates to the field of new energy commercial vehicles, and in particular to a dual-motor drive system and vehicle. Background Technology

[0002] New energy commercial vehicles (including trucks and buses) need to meet various operating conditions, including mountain climbing, urban commuting, and intercity highway operation. Their drive systems need to have multi-condition adaptability and high drive efficiency.

[0003] The drive system of new energy commercial vehicles can adopt a dual drive motor system. Currently, the dual drive motor system includes two drive motors and a reducer. The reducer includes two input shafts, which are connected to the two drive motors respectively. The two input shafts are connected to the same set of gear mechanisms, resulting in low system transmission accuracy. The reducer and the two drive motors are installed in two separate housings, resulting in a large system size and weight. When one motor in the dual drive motor system is driven alone, the rotor of the other motor will generate back electromotive force and cogging torque due to idling, causing high energy loss. The operating points of the two drive motors are not distributed in the high-efficiency range, resulting in poor adaptability to multiple operating conditions, low system drive efficiency, and low energy utilization. Summary of the Invention

[0004] The present invention aims to address the shortcomings of the prior art by providing a dual-motor drive system and vehicle, thereby improving the transmission accuracy of the drive system and reducing energy loss.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is: a dual-motor drive system, comprising:

[0006] The speed reducer includes a first gear train reduction mechanism and a second gear train reduction mechanism;

[0007] The main drive motor is connected to the first gear reduction mechanism;

[0008] A secondary drive motor is connected to the second gear reduction mechanism;

[0009] The main drive motor is a synchronous motor, and the auxiliary drive motor is an asynchronous motor.

[0010] In the dual-motor drive system of the present invention, the main drive motor and the auxiliary drive motor are respectively connected to the first gear reduction mechanism and the second gear reduction mechanism, resulting in high transmission accuracy. The main drive motor is a synchronous motor and the auxiliary drive motor is an asynchronous motor. When the main drive motor drives alone, the stator of the auxiliary drive motor is not energized, so it does not generate back electromotive force and there is no additional energy loss.

[0011] In this invention, the reduction ratio of the main drive motor is less than the reduction ratio of the auxiliary drive motor.

[0012] The reduction ratio of the main drive motor is smaller than that of the auxiliary drive motor. The main drive motor is mainly used for high-speed driving conditions. Choosing a smaller reduction ratio can distribute the operating points within the motor's high-efficiency range. The auxiliary drive motor is mainly used for climbing and acceleration conditions. Choosing a larger reduction ratio can distribute the operating points within the motor's high-efficiency range, resulting in greater climbing torque and acceleration. The two motors correspond to different reduction ratios, which allows each motor to operate within its high-efficiency range, improving the system's drive efficiency and further reducing energy consumption.

[0013] Furthermore, the output shaft of the main drive motor is coaxial with the input shaft of the first gear reduction mechanism, and the output shaft of the auxiliary drive motor is coaxial with the input shaft of the second gear reduction mechanism. The integrated design of the drive motor's output shaft and the reducer's input shaft improves the system's transmission accuracy.

[0014] Furthermore, the first gear system reduction mechanism includes a plurality of gears that are driven sequentially, wherein the shaft of the input gear of the first gear system reduction mechanism is coaxial with the output shaft of the main drive motor; the second gear system reduction mechanism includes a plurality of gears that are driven sequentially, wherein the shaft of the input gear of the second gear system reduction mechanism is coaxial with the output shaft of the auxiliary drive motor; the shaft of the output gear of the first gear system reduction mechanism is coaxial with the shaft of the output gear of the second gear system reduction mechanism.

[0015] Furthermore, the first gear reduction mechanism includes a sixth gear, a seventh gear, an eighth gear, and a ninth gear; the second gear reduction mechanism includes a first gear, a second gear, a third gear, a fourth gear, and a fifth gear; the first gear and the second gear mesh, the second gear and the third gear are coaxial, the third gear and the fourth gear mesh, the fourth gear and the fifth gear are coaxial, and the fifth gear and the sixth gear mesh; the ninth gear and the eighth gear mesh, the eighth gear and the seventh gear are coaxial, and the seventh gear and the sixth gear mesh.

[0016] In this invention, the first and second gears constitute the first-stage reduction of the second gear system reduction mechanism, the third and fourth gears constitute the second-stage reduction, and the fifth and sixth gears constitute the third-stage reduction; the ninth and eighth gears constitute the first-stage reduction of the first gear system reduction mechanism, and the seventh and sixth gears constitute the second-stage reduction. The multi-stage reduction gear structure reduces the size and moment of inertia of the gears, thus reducing the size of the reducer and consequently the drive system, while simultaneously improving the transmission accuracy of the drive system.

[0017] Furthermore, the main drive motor, the auxiliary drive motor, and the reducer are installed in the same housing, reducing the system weight and size.

[0018] Furthermore, in this invention, the main drive motor is a flat wire permanent magnet synchronous motor, and the auxiliary drive motor is an induction asynchronous motor.

[0019] In this invention, the auxiliary drive motor is a flat wire asynchronous motor, which has the advantages of high speed and high efficiency.

[0020] The main drive motor of this invention is a flat-wire permanent magnet synchronous motor, which has the advantages of high power factor and high efficiency. The auxiliary drive motor is an induction asynchronous motor. When the main drive motor drives the rotor of the auxiliary drive motor to rotate, the stator of the auxiliary drive motor is not energized, so no back electromotive force is generated and there is no additional energy loss.

[0021] As an inventive concept, the present invention also provides a vehicle that employs the aforementioned dual-motor drive system.

[0022] Compared with the prior art, the beneficial effects of the present invention are:

[0023] The dual-motor drive system of the present invention has a main drive motor that is a synchronous motor and an auxiliary drive motor that is an asynchronous motor. When the main drive motor drives alone, the auxiliary drive motor does not generate back electromotive force and there is no additional energy loss.

[0024] Each drive motor corresponds to a different reduction ratio, which can make the operating points of each motor evenly distributed in the high-efficiency range, improve the system drive efficiency, and reduce energy consumption;

[0025] The integrated design of the drive motor output shaft and the reducer input shaft improves the transmission accuracy and structural strength of the drive system.

[0026] The gear structure adopts multi-stage reduction, which reduces the size of the gears, reduces the moment of inertia of the gears, and reduces the size of the reducer.

[0027] The dual drive motors and reducers are installed in the same housing, which reduces the weight and size of the drive system. Attached Figure Description

[0028] Figure 1 is a topology diagram of a dual-drive motor system according to an embodiment of the present invention;

[0029] Figure 2 is a structural diagram of the dual-drive motor system according to an embodiment of the present invention;

[0030] Figure 3 shows the high-efficiency zone of the main drive motor in an embodiment of the present invention;

[0031] Figure 4 is a mechanical transmission diagram of the main drive motor driving alone in an embodiment of the present invention;

[0032] Figure 5 shows the high-efficiency zone of the auxiliary drive motor in an embodiment of the present invention;

[0033] Figure 6 is a mechanical transmission diagram of the auxiliary drive motor driving alone according to an embodiment of the present invention;

[0034] Figure 7 is a mechanical transmission diagram of the main drive motor and the auxiliary drive motor driving simultaneously in an embodiment of the present invention.

[0035] In the diagram: 1-First gear; 2-Second gear; 3-Third gear; 4-Fourth gear; 5-Fifth gear; 6-Sixth gear; 7-Seventh gear; 8-Eighth gear; 9-Ninth gear; 10-Main drive motor; 11-Secondary drive motor; 12-Reducer; 13-Secondary drive motor output shaft; 14-Main drive motor output shaft; 15-Output shaft of the dual-motor drive system. Detailed Implementation

[0036] The present invention will be described in detail below with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of the present invention can be combined with each other. For ease of description, the terms "upper," "lower," "left," and "right" appearing below only indicate that they correspond to the upper, lower, left, and right directions of the drawings themselves, and do not limit the structure. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Example

[0037] This embodiment 1 provides a dual-motor drive system, as shown in Figures 1 and 2. The dual-motor drive system includes two drive motors and a reducer. The main drive motor M1 is a flat-wire permanent magnet synchronous motor, and the auxiliary drive motor M2 is a flat-wire asynchronous motor. The reducer includes a first gear reduction mechanism and a second gear reduction mechanism. The output shaft of the main drive motor and the input shaft of the first gear reduction mechanism are on the same shaft (coaxial), and the output shaft of the auxiliary drive motor and the input shaft of the second gear reduction mechanism are on the same shaft. The sixth, seventh, eighth, and ninth gears form the first gear reduction mechanism with a reduction ratio of i1, connecting motor M1 and the output shaft of the dual-motor drive system. The shaft of the ninth gear (the input side gear of the first gear reduction mechanism) is the output shaft of the main drive motor M1 and also the input shaft of the first gear reduction mechanism. The ninth gear meshes with the eighth gear, the eighth gear and the seventh gear are coaxial, and the seventh gear meshes with the sixth gear. The ninth gear and the eighth gear constitute the first stage of reduction in the first gear reduction mechanism, and the seventh gear and the sixth gear constitute the second stage of reduction in the first gear reduction mechanism. The first, second, third, fourth, fifth, and sixth gears form a second gear reduction mechanism with a reduction ratio of i2. This mechanism connects the auxiliary drive motor M2 to the output shaft of the dual-motor drive system. The shaft of the first gear (the input gear of the second gear reduction mechanism) is the output shaft of motor M2 and also the input shaft of the second gear reduction mechanism. The first and second gears mesh; the second and third gears are coaxial; the third and fourth gears mesh; the fourth and fifth gears are coaxial; and the fifth gear (the output gear of the second gear reduction mechanism) and the sixth gear (the output gear of the first gear reduction mechanism) mesh. The first and second gears constitute the first stage of reduction in the second gear reduction mechanism; the third and fourth gears constitute the second stage; and the fifth and sixth gears constitute the third stage. Where i1 < i2.

[0038] The main drive motor, auxiliary drive motor, and reducer are installed in the same housing.

[0039] The operating mode of the dual-motor drive system in this embodiment is as follows:

[0040] (1) M1 motor main drive

[0041] The M1 motor is a flat-wire permanent magnet synchronous motor, characterized by high power factor and high efficiency. This design places the high-efficiency region of the M1 motor within the low-torque region (see Figure 3), and utilizes a relatively small reduction ratio i1. As shown in Figure 4, when the M1 motor drives the vehicle alone, it functions similarly to the overdrive / high-speed gear in a traditional gasoline-powered vehicle, meeting the vehicle's high-speed stability requirements while also satisfying its low-speed, low-speed acceleration, and low-speed hill-climbing needs. In this state, the M1 motor operates within its high-efficiency region, minimizing energy loss.

[0042] As shown in Figure 1, when motor M1 is working, it drives the rotor of motor M2 to rotate. If motor M2 is a permanent magnet synchronous motor, a back electromotive force will be generated inside it. The cogging torque of the permanent magnet will lead to energy loss and reduce driving efficiency. Therefore, in this embodiment, motor M2 is designed as an asynchronous motor. When motor M1 drives the rotor of motor M2 to rotate, the stator of motor M2 is not energized, and no back electromotive force is generated, resulting in no additional energy loss.

[0043] (2) M2 motor auxiliary drive

[0044] The M2 motor is a flat-wire asynchronous motor, which has the advantages of high speed and high efficiency. By selecting a relatively large reduction ratio i2, the operating range of the M2 motor is distributed in the high-speed, low-torque range (see Figure 5). As shown in Figure 6, when the M2 motor is driven alone, it is equivalent to the medium and low speed gears of a traditional fuel vehicle, which meets the general low-speed climbing requirements of the vehicle. At this time, the M2 motor operates in the high-efficiency range, which can reduce energy loss.

[0045] (3) M1+M2 dual motor drive

[0046] As shown in Figure 7, when motors M1 and M2 are driven simultaneously, their maximum power output is equivalent to the first gear of a traditional gasoline vehicle, which can meet the vehicle's starting acceleration and extreme hill climbing requirements, as well as the vehicle's low-speed acceleration and high-speed overtaking requirements. Details are as follows:

[0047] ①When the vehicle starts, both motors start simultaneously, providing sufficient starting torque and acceleration torque. After the vehicle is running normally, motor M1 works alone.

[0048] ② When the vehicle is running at low or high speed, and encounters situations requiring rapid acceleration or climbing, the M2 motor responds quickly and works together with the M1 motor to drive the vehicle and meet its power requirements.

[0049] (4) Individual energy recovery of M1 motor

[0050] Because permanent magnet synchronous motors are more efficient than asynchronous motors, the M1 motor is used for brake energy recovery during normal braking and coasting conditions of the vehicle.

[0051] (5) Energy recovery of M1+M2 dual motors

[0052] Because the braking torque of a single M1 motor or a single M2 motor is relatively small, when the vehicle needs to brake urgently or encounters a long downhill condition, the M1 motor and the M2 motor will participate in electric braking simultaneously to improve the vehicle's braking efficiency, shorten the braking distance, and improve the energy recovery rate.

[0053] The structural features of the dual-motor drive system in this embodiment are as follows:

[0054] (1) The motor housing and the reducer housing are an integral structure, which improves the strength of the transmission structure, reduces weight, and reduces volume;

[0055] (2) The output shaft of the drive motor is integrated with the input shaft of the reducer. The corresponding first gear and ninth gear are integrated with the output shafts of motors M2 and M1, respectively. Compared with other dual-motor drive systems, the dual motor and reducer are integrated, resulting in high transmission accuracy, improved structural strength, and reduced system weight and volume.

[0056] (3) Compared with other dual-motor drive systems, the M2 motor is a flat wire asynchronous motor, which solves the problem that the rotor will generate back electromotive force and cogging torque when the M1 motor drives alone and the M2 motor is a permanent magnet synchronous motor, resulting in energy loss.

[0057] (4) Compared with other dual-motor drive systems, each drive motor corresponds to a different reduction ratio, which can make the operating points of each drive motor distributed in the high-efficiency range, thereby improving the system drive efficiency;

[0058] (5) Compared with other dual-motor drive systems, this embodiment uses a flat wire motor, which reduces the weight and volume of the dual-motor drive system, saves vehicle installation space, and improves the efficiency of the drive system. Example

[0059] This embodiment provides a vehicle that uses the dual-motor drive system of Embodiment 1 described above.

[0060] The vehicle in this embodiment can be a pure electric vehicle, a hybrid electric vehicle, or a gas-electric hybrid vehicle.

[0061] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0062] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A dual-motor drive system, characterized in that, include: The speed reducer includes a first gear train reduction mechanism and a second gear train reduction mechanism; The main drive motor is connected to the first gear reduction mechanism; A secondary drive motor is connected to the second gear reduction mechanism; The main drive motor is a synchronous motor, and the auxiliary drive motor is an asynchronous motor.

2. The dual-motor drive system according to claim 1, characterized in that, The reduction ratio of the main drive motor is less than that of the auxiliary drive motor.

3. The dual-motor drive system according to claim 1, characterized in that, The output shaft of the main drive motor is coaxial with the input shaft of the first gear reduction mechanism.

4. The dual-motor drive system according to claim 1, characterized in that, The output shaft of the auxiliary drive motor is coaxial with the input shaft of the second gear reduction mechanism.

5. The dual-motor drive system according to any one of claims 1 to 4, characterized in that, The first gear reduction mechanism includes multiple gears that are driven sequentially, wherein the shaft of the input gear of the first gear reduction mechanism is coaxial with the output shaft of the main drive motor.

6. The dual-motor drive system according to claim 5, characterized in that, The second gear system reduction mechanism includes multiple gears that are driven sequentially, wherein the shaft of the input gear of the second gear system reduction mechanism is coaxial with the output shaft of the auxiliary drive motor; the shaft of the output gear of the first gear system reduction mechanism is coaxial with the shaft of the output gear of the second gear system reduction mechanism.

7. The dual-motor drive system according to claim 6, characterized in that, The first gear reduction mechanism includes a sixth gear, a seventh gear, an eighth gear, and a ninth gear; the second gear reduction mechanism includes a first gear, a second gear, a third gear, a fourth gear, and a fifth gear; the first gear and the second gear mesh, the second gear and the third gear are coaxial, the third gear and the fourth gear mesh, the fourth gear and the fifth gear are coaxial, and the fifth gear and the sixth gear mesh. The ninth gear meshes with the eighth gear, the eighth gear and the seventh gear are coaxial, and the seventh gear meshes with the sixth gear.

8. The dual-motor drive system according to claim 1, characterized in that, The main drive motor, the auxiliary drive motor, and the reducer are installed in the same housing.

9. The dual-motor drive system according to claim 1, characterized in that, The main drive motor is a flat wire permanent magnet synchronous motor, and the auxiliary drive motor is an induction asynchronous motor.

10. A vehicle, characterized in that, It employs the dual-motor drive system described in any one of claims 1 to 9.

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