A master-slave cooperative dual-motor electric drive axle configuration and a control method thereof

Abstract

The application belongs to the technical field of vehicle electric drive, and provides a main-aid collaborative double-motor electric drive axle configuration and a control method thereof, and the technical scheme comprises a gear shaft system matched with a main motor and comprising at least one first synchronizer, a gear shaft system matched with an auxiliary motor and comprising at least one second synchronizer; each three-stage planetary gear set reduction gear shifting mechanism comprises at least one third synchronizer and one planetary gear reduction mechanism, a gear shifting fork is arranged on each first synchronizer, second synchronizer and third synchronizer, and the gear shifting fork is connected to a controller; in each driving mode, a corresponding motor driving control strategy is adopted to output a driving torque distributed by a motor; based on the output driving torque distributed by the motor and a gear shifting switching strategy, the gear shifting forks of the synchronizers are switched to realize multi-gear shifting. On the premise of compact overall arrangement, system efficiency optimization is ensured in the whole working condition range.

Description

Technical Field

[0001] This invention belongs to the field of vehicle electric drive technology, and particularly relates to a dual-motor electric drive bridge configuration with main and auxiliary motors and its control method. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] Driven by both environmental protection and economic benefits, the electrification of commercial vehicles, especially heavy-duty trucks, has become an irreversible trend. As a highly integrated powertrain, the electric drive axle directly determines the vehicle's power, range, and economy. Heavy-duty trucks operate under complex conditions with large load variations, requiring the electric drive axle to deliver massive torque at low speeds and achieve efficient cruising at high speeds. Therefore, electric drive axles with multi-speed transmission capabilities have become a key technological approach to expanding the efficient operating range of the electric motor while balancing power and energy efficiency.

[0004] Currently, the technological development of multi-speed electric drive bridges in the industry mainly presents two typical approaches:

[0005] The first type is a multi-motor parallel drive scheme centered on "torque superposition," such as an expandable configuration using a planetary gear set combined with a parallel shaft reduction mechanism. This scheme achieves power superposition through torque converging, demonstrating good modular potential. However, the expansion approach of this configuration relies too heavily on simply increasing the number of motors to increase power, rather than improving energy efficiency through optimizing gear shifting and power source coordination. As a result, multiple motors work together with a fixed mechanical connection, and the system lacks the ability to intelligently decouple and divide the power source according to operating conditions. Under most low-to-medium load cruising conditions, all motors remain mechanically bound and cannot be completely separated, leading to unnecessary idling drag losses and iron losses, which in turn reduces the overall efficiency of the system. In other words, while this scheme solves the problem of "insufficient power," it exacerbates the problem of "excessive energy consumption," and its extensive energy management strategy is accompanied by increased control complexity and cost. To address this technical challenge, improved energy-efficient main and auxiliary motor configurations have emerged in the industry. Current solutions utilize a four-speed parallel-shaft main motor in conjunction with an auxiliary motor to achieve uninterrupted gear switching and improved energy efficiency. However, the parallel-shaft arrangement adopted to achieve multiple speeds inevitably leads to the separation of the motor's orientation from the gear shaft system, significantly increasing the axial length of the electric drive axle. This not only makes the overall structure less compact but, more importantly, lengthens the left half-shaft, weakening its torsional stiffness and transmission reliability. Furthermore, the reverse arrangement of the two motors disrupts the system's structural harmony, potentially negatively impacting performance.

[0006] The second type is a single-motor planetary gear shifting scheme centered on "structural optimization." It achieves two gears by switching the input point of the planetary gear set, and the fixed internal gear ring design also improves rigidity. However, this scheme is inherently limited by the limitations of a single power source. Under any operating condition, a single motor must independently undertake all driving tasks, and its efficiency is "averaged" by the complex operating conditions, making it difficult to maintain a consistently high-efficiency range, exhibiting a clear "efficiency ceiling." At the same time, the power limit of a single motor also restricts further improvements in the vehicle's ultimate power. Summary of the Invention

[0007] To address at least one of the technical problems mentioned above, this invention provides a dual-motor electric drive bridge configuration that integrates main and auxiliary motors. This configuration inherits the advantages of multi-motor systems, such as strong power and good scalability, while incorporating the concepts of intelligent energy management and optimized structural layout. It enables on-demand allocation and efficient coordination of power sources, thereby fundamentally improving the energy utilization efficiency of heavy trucks under all operating conditions.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] The first aspect of the present invention provides a dual-motor electric drive bridge configuration with main and auxiliary motors working together, including a main motor and a gear shaft system matched with the main motor, an auxiliary motor and a gear shaft system matched with the auxiliary motor, and an output shaft; wherein the main motor and the gear shaft system matched with the main motor, the auxiliary motor and the gear shaft system matched with the auxiliary motor are all arranged in a mirror symmetrical manner with the output shaft as the center;

[0010] The configuration also includes a controller and at least one three-stage planetary gear reducer shifting mechanism. The gear shaft system matched with the main motor includes at least one first synchronizer, and the gear shaft system matched with the auxiliary motor includes at least one second synchronizer. Each three-stage planetary gear reducer shifting mechanism includes at least one third synchronizer and a planetary gear reducer mechanism. Each first synchronizer, second synchronizer, and third synchronizer is provided with a shift fork, and the state of the shift fork is controlled by the controller.

[0011] The controller is configured to: based on the collected real-time vehicle status operating data and motor drive mode, in each drive mode, output the drive torque allocated to the motor using a corresponding motor drive control strategy; determine whether gear shifting is required, and if so, control the shift forks of each synchronizer to switch based on the output drive torque allocated to the motor and the gear shifting strategy to achieve multi-gear switching.

[0012] Furthermore, the gear shaft system matched with the main motor also includes a main motor reduction mechanism, a first-gear drive gear, and a second-gear drive gear; the main motor reduction mechanism includes a main motor first-stage reduction driven gear shaft, a main motor first-stage reduction drive gear, and a main motor first-stage reduction driven gear. The main motor first-stage reduction drive gear is connected to the input shaft of the main motor, the main motor first-stage reduction driven gear is fixed to the main motor first-stage reduction driven gear shaft, and the main motor first-stage reduction driven gear meshes with the main motor first-stage reduction drive gear. The first synchronizer selectively engages with the first-gear drive gear or the second-gear drive gear according to the working conditions to achieve power transmission and gear selection.

[0013] Furthermore, the gear shaft system matched with the auxiliary motor also includes an auxiliary motor reduction mechanism. The auxiliary motor reduction mechanism includes an auxiliary motor first-stage reduction driven gear shaft, an auxiliary motor first-stage reduction driven gear, an auxiliary motor first-stage reduction driving gear, and an auxiliary motor second-stage reduction driving gear. The auxiliary motor first-stage reduction driven gear is fixed to the auxiliary motor first-stage reduction driven gear shaft. The auxiliary motor first-stage reduction driving gear is connected to the input shaft of the auxiliary motor, and the auxiliary motor first-stage reduction driven gear and the auxiliary motor first-stage reduction driving gear mesh. The second synchronizer engages or disengages with the auxiliary motor second-stage reduction driving gear according to the working conditions to transmit and disengage power. The gear shaft system matched with the auxiliary motor also includes a third needle roller bearing. The auxiliary motor second-stage reduction driving gear is mounted to the auxiliary motor first-stage reduction driven gear shaft through the third needle roller bearing.

[0014] Furthermore, the highest gear of the main motor is set on the side close to the main motor, and the auxiliary motor forms a three-tooth meshing structure with the highest gear of the main motor.

[0015] Furthermore, the three-stage planetary gear reducer also includes a left supporting planetary carrier, a right supporting planetary carrier, a sun gear, planetary gears, and an internal gear ring. Both the left and right supporting planetary carriers have holes into which planetary gear pins are inserted. The left and right supporting planetary carriers are connected by planetary gear pins to jointly support the rotation of the planetary gears. Needle roller bearings are installed between the planetary gears and the planetary gear pins. The sun gear, planetary gears, and internal gear ring mesh with each other.

[0016] Furthermore, in each driving mode, a corresponding motor drive control strategy is adopted to output the driving torque allocated to the motor, including:

[0017] In the single-motor high-efficiency drive mode of the main motor, the control second synchronizer is disconnected, the auxiliary motor is disengaged, the auxiliary motor is decoupled from the transmission system, and the main motor is driven independently.

[0018] In the dual-motor drive mode with main and auxiliary motors working in tandem, the control of the second synchronizer is activated by adjusting the operating torque of the main motor. and the operating torque of the auxiliary motor The power output of the electric drive axle assembly is minimized while still meeting the required driving torque for the entire vehicle.

[0019] A second aspect of the present invention provides a control method for a dual-motor electric drive bridge configuration with primary and secondary cooperative operation, comprising the following steps:

[0020] Acquire real-time vehicle status and operating data;

[0021] The motor drive mode is determined based on the real-time vehicle status data. In each drive mode, the corresponding motor drive control strategy is adopted to output the drive torque allocated to the motor.

[0022] Determine whether a gear shift is needed. If so, based on the driving torque allocated to the output motor and the gear shifting strategy, control the shift forks of each synchronizer to switch to achieve multi-gear switching.

[0023] The method further includes determining the motor braking mode based on real-time vehicle operating data, and matching a braking energy recovery strategy according to the motor braking mode, including:

[0024] It receives sensor inputs such as brake pedal depth, brake pedal travel rate, vehicle speed, battery SOC, motor temperature, and current gear information, and determines the braking intensity level and the maximum regenerative power of the system accordingly.

[0025] The ratio of motor braking to mechanical braking is determined based on the output braking intensity level and the maximum regenerative power. If the braking is identified as an emergency braking, mechanical braking is used entirely. If the braking is identified as a non-emergency braking, the braking force is distributed according to the current driving mode: in single-motor driving mode, braking force is distributed between the main motor and mechanical braking; in dual-motor operating mode, braking force is distributed between the dual motors and mechanical braking.

[0026] Furthermore, the motor drive mode includes a single-motor drive mode and a main-auxiliary coordinated dual-motor drive mode; the specific criteria for judgment are:

[0027] If the required driving torque Tq of the whole vehicle is less than or equal to the maximum efficient output torque of the main motor in the current gear, the temperature of the main motor is lower than the first temperature threshold T1, the battery SOC is within the set normal working range and the throttle opening change is less than the set threshold, then the single motor efficient drive mode of the main motor is adopted.

[0028] If the required driving torque Tq of the whole vehicle is greater than the maximum sustainable output torque of the main motor in the current gear, the temperature of the main motor exceeds the first temperature threshold T1, or the throttle opening change rate exceeds the threshold, then the main and auxiliary coordinated dual motor drive mode is adopted.

[0029] Furthermore, based on the drive torque allocated to the output motor and the shifting strategy, the system switches to the corresponding gear, including:

[0030] When the first synchronizer engages the I gear drive gear on the left and the third synchronizer of the planetary gear shifting mechanism engages the housing shifting assembly on the right, the auxiliary motor joins or disengages through the second synchronizer according to the torque requirement, outputting the first speed ratio as the first gear;

[0031] When the first synchronizer engages the second gear drive gear on the right, and the third synchronizer of the planetary gear shifting mechanism engages the housing shifting assembly on the right, the auxiliary motor joins or disengages through the second synchronizer according to the torque requirement, outputting the second speed ratio as the second gear;

[0032] When the first synchronizer engages the first gear drive gear on the left, and the third synchronizer of the planetary gear shifting mechanism engages the planetary carrier shifting assembly on the left, the auxiliary motor joins or disengages through the second synchronizer according to torque requirements, outputting the third speed ratio as the third gear;

[0033] When the first synchronizer engages the second gear drive gear on the right and the third synchronizer of the planetary gear shifting mechanism engages the planetary carrier shifting assembly on the left, the auxiliary motor joins or disengages through the second synchronizer according to torque requirements, outputting the fourth speed ratio as the fourth gear.

[0034] Compared with the prior art, the beneficial effects of the present invention are:

[0035] This invention employs a layout concept combining parallel shaft multi-gear with planetary gear set multi-gear, and a design approach that balances compactness and reliability. Multiple gears can be set via multiple first synchronizers on the main motor, and multiple three-stage planetary gear set reduction and shifting mechanisms can be implemented. Each three-stage planetary gear set reduction and shifting mechanism offers multiple gears, allowing for gear shifting based on a multiplicative relationship as needed, providing high selectivity. While maintaining a compact layout, this invention maximizes system efficiency across all operating conditions.

[0036] This invention features a main motor with two selectable gears in a two-stage reduction configuration, while the auxiliary motor has only a single gear in its two-stage reduction configuration. The auxiliary motor can be decoupled from the main motor via a synchronizer to reduce drag energy loss. The third-stage reduction is a two-gear planetary gear reducer. By selecting the synchronizer's engagement method, the two gears of the planetary gear reducer can be switched. Smooth speed ratio switching can be achieved by combining the two gears of the main motor with the two gears of the planetary gear reducer, maximizing the main motor's operation within its efficient speed range. Through an intelligent torque distribution strategy, efficient matching across the entire range is achieved.

[0037] This invention features a two-gear parallel shaft combined with a two-gear planetary gear set, satisfying multiple requirements such as low-speed torque, high-speed range, and adaptability to complex operating conditions. It also solves the problems of excessive axial dimension and incompatibility with the opposite motor arrangement caused by directly placing four gears on the parallel shaft. Allocating gears to the planetary gear train mechanism not only significantly reduces the axial dimension of the electric drive axle, improving compatibility with many converted electric vehicles, but also increases torque and speed of the auxiliary motor, improving its energy utilization. Compared to a structure that simply amplifies torque through superposition, this gear arrangement offers more possibilities for motor selection and control.

[0038] The auxiliary motor of this invention largely solves the problem of insufficient torque in single-motor heavy-duty vehicles, can meet the torque requirements of vehicles under harsh working conditions, and can also work in the high-efficiency operating range in conjunction with the main motor.

[0039] Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0040] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0041] Figure 1 This is a schematic diagram of the electric drive bridge arrangement provided in an embodiment of the present invention;

[0042] Figure 2 This is a schematic diagram of the overall structure of the main-auxiliary cooperative dual-motor electric drive bridge configuration provided in an embodiment of the present invention;

[0043] Figure 3 This is a schematic diagram of the output shaft assembly structure provided in an embodiment of the present invention;

[0044] Figure 4 This is a schematic diagram of the six-speed electric drive bridge structure provided in an embodiment of the present invention;

[0045] Figure 5 This is a schematic diagram of the four-speed electric drive bridge structure provided in an embodiment of the present invention;

[0046] Figure 6 This is a schematic diagram of a first-gear transmission provided in an embodiment of the present invention;

[0047] Figure 7 This is a schematic diagram of a two-speed transmission provided in an embodiment of the present invention;

[0048] Figure 8 This is a schematic diagram of a three-speed transmission provided in an embodiment of the present invention;

[0049] Figure 9 This is a schematic diagram of a four-speed transmission provided in an embodiment of the present invention;

[0050] Among them, 1. Main motor; 2. Main motor first-stage reduction drive gear; 3. Main motor first-stage reduction driven gear; 4. Second gear drive gear; 5. First synchronizer; 6. First gear drive gear; 7. Main motor first-stage reduction driven gear shaft; 8. First needle roller bearing; 9. Second needle roller bearing; 10. Second synchronizer; 11. Auxiliary motor first-stage reduction driven gear shaft; 12. Third needle roller bearing; 13. Auxiliary motor second-stage reduction drive gear; 14. Auxiliary motor first-stage reduction driven gear; 15. Auxiliary motor first-stage reduction drive gear; 16. Auxiliary motor; 17. Left half 18. Output shaft; 19. I-gear driven gear; 20. II-gear driven gear; 21. First support housing; 22. Planetary carrier shift assembly; 23. Third synchronizer; 24. Second support housing; 25. Housing shift assembly; 26. Internal gear ring; 27. Planetary gear; 28. Left support planetary carrier; 29. ​​Planetary gear pin; 30. Fourth needle roller bearing; 31. Differential; 32. Right half shaft; 33. First differential bevel gear; 34. Second differential bevel gear; 35. Sun gear; 36. Right support planetary carrier; 37. Internal gear ring shift assembly. Detailed Implementation

[0051] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0052] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0053] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0054] In this invention, terms such as "left" and "right" indicate orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings. They are merely relational terms determined for the convenience of describing the structural relationships of the various components or elements of this invention, and do not specifically refer to any component or element in this invention, nor should they be construed as limitations on this invention.

[0055] In this invention, terms such as "fixed connection," "connected," and "linked" should be interpreted broadly, indicating a fixed connection, an integral connection, or a detachable connection; a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can determine the specific meaning of these terms in this invention based on the specific circumstances, and they should not be construed as limitations on the invention.

[0056] Existing electric drive axle solutions, whether multi-motor parallel drive or single-motor planetary gear shifting, have failed to adequately address the core challenge of "optimizing system efficiency across all operating conditions while maintaining a compact layout." Multi-motor parallel drive solutions, centered on "torque superposition," possess the potential of multiple power sources, but structural redundancy or outdated control strategies lead to additional energy losses. Single-motor planetary gear shifting solutions, centered on "structural optimization," achieve two gears through structural optimization, but their efficiency improvement is limited by the single motor.

[0057] The electric drive bridge configuration of this invention adopts a symmetrical arrangement of the main motor and auxiliary motor, which improves the coordination of the system layout. The main motor has two selectable gears in its two-stage reduction gear, while the auxiliary motor has only one gear in its two-stage reduction gear. It can also be decoupled from the main motor through a synchronizer to reduce drag energy loss. The three-stage reduction gear is a two-gear planetary gear reducer. By selecting the combination method of the synchronizer, the two gears of the planetary gear reducer mechanism can be switched. By matching the two gears of the main motor with the two gears of the planetary gear, smooth speed ratio switching can be achieved, so as to maximize the operation of the main motor in the high-efficiency speed range. Through intelligent torque distribution strategy, it works in coordination to achieve high-efficiency matching across the entire range.

[0058] Furthermore, the highest gear of the main motor is located near the motor side, and the auxiliary motor forms a three-tooth meshing structure with the highest gear of the main motor. Structurally, this shortens the axial distance of the auxiliary motor's output shaft, reducing the coupling cost between the auxiliary and main motors. The auxiliary motor only needs a lower speed to match the full speed of the main motor, thereby reducing the development cost of the auxiliary motor. In terms of performance, it can reduce the speed fluctuation of the auxiliary motor and enable a faster intervention response. The use of the auxiliary motor largely solves the problem of insufficient torque in single-motor heavy-duty vehicles, meeting the torque requirements of vehicles under harsh operating conditions and working in the efficient operating range with the main motor. The two-gear shifting mode of the parallel shaft combined with the two-gear planetary gear set not only meets multiple requirements such as low-speed torque, high-speed range, and adaptability to complex operating conditions, but also solves the problems of excessive axial dimension of the system and incompatibility with the opposite motor arrangement direction caused by directly placing four gears on the parallel shaft. Distributing gears to the planetary gear train not only significantly reduces the axial dimension of the electric drive axle, making it more compatible with many converted electric vehicles, but also reduces speed and increases torque for the auxiliary motor, improving its energy utilization. Compared to a structure that amplifies torque by a single ratio, this gear arrangement offers more possibilities for motor selection and control.

[0059] In summary, in terms of performance and structural layout, this invention inherits the advantages of multi-motor systems in terms of strong power and good expandability; in terms of efficiency, it meets multiple requirements such as low-speed torque, high-speed range and adaptability to complex working conditions through four gears, while the coordinated cooperation of the two motors ensures that the main and auxiliary motors can work in the high-efficiency speed range; in terms of structure, it retains the multi-gear design concept while greatly shortening the overall layout axial space and improving coordination.

[0060] Please refer to Figure 1 The overall structure of a main-auxiliary cooperative dual-motor electric drive bridge configuration is as follows: Figure 1 As shown, it includes a main motor 1 and a gear shaft system matched with the main motor, an auxiliary motor 16 and a gear shaft system matched with the auxiliary motor, wherein the main motor 1 and the gear shaft system matched with the main motor, and the auxiliary motor 16 and the gear shaft system matched with the auxiliary motor are all arranged in a mirror symmetrical manner with the output shaft 18 as the center.

[0061] Please refer to Figure 2 The gear shaft system matched with the main motor specifically includes the main motor first-stage reduction drive gear 2, the main motor first-stage reduction driven gear 3, the second-stage drive gear 4, the first synchronizer 5, the first-stage drive gear 6, and the main motor first-stage reduction driven gear shaft 7.

[0062] The main motor's first-stage reduction drive gear 2 is connected to the input shaft of the main motor 1. The main motor's first-stage reduction driven gear 3 is fixed to the main motor's first-stage reduction driven gear shaft 7, and the main motor's first-stage reduction driven gear 3 meshes with the main motor's first-stage reduction drive gear 2. The main motor's first-stage reduction driven gear shaft 7 is also equipped with a first-gear drive gear 6 and a second-gear drive gear 4. The first-gear drive gear 6 is mounted on the main motor's first-stage reduction driven gear shaft 7 via a first needle roller bearing 8, and the second-gear drive gear 4 is mounted on the main motor's first-stage reduction driven gear shaft 7 via a second needle roller bearing 9. The main motor's first-stage reduction driven gear shaft 7 is also fixed with a first synchronizer 5, which can be selected to engage with either the first-gear drive gear 6 or the second-gear drive gear 4 according to the working conditions to achieve power transmission and gear selection.

[0063] In this embodiment, the main motor first-stage reduction drive gear 2 and the input shaft of the main motor 1 are connected by a spline to transmit torque, and the first synchronizer 5 is fixedly connected to the main motor first-stage reduction driven gear shaft 7 by a spline connection.

[0064] Continue to refer to Figure 2 The gear shaft system matched with the auxiliary motor specifically includes a second synchronizer 10, an auxiliary motor first-stage reduction driven gear shaft 11, a third needle roller bearing 12, an auxiliary motor second-stage reduction driving gear 13, an auxiliary motor first-stage reduction driven gear 14, and an auxiliary motor first-stage reduction driving gear 15.

[0065] The auxiliary motor's primary reduction drive gear 15 is connected to the input shaft of the auxiliary motor 16. The auxiliary motor's primary reduction driven gear 14 is fixed to the auxiliary motor's primary reduction driven gear shaft 11, and the auxiliary motor's primary reduction driven gear 14 meshes with the auxiliary motor's primary reduction drive gear 15. The auxiliary motor's primary reduction driven gear shaft 11 is also equipped with an auxiliary motor's secondary reduction drive gear 13 and a second synchronizer 10. The auxiliary motor's secondary reduction drive gear 13 is mounted to the auxiliary motor's primary reduction driven gear shaft 11 via a third needle roller bearing 12. The driven gear shaft 11 of the primary reduction gear of the auxiliary motor can rotate relative to each other with the help of the third needle roller bearing 12. Since the secondary reduction gear 13 of the auxiliary motor and the driven gear shaft 11 of the primary reduction gear of the auxiliary motor are an integral structure, the torque can only be transmitted through the second synchronizer 10 in conjunction with the secondary reduction gear 13 of the auxiliary motor. The second synchronizer 10 can selectively engage or disengage with the secondary reduction gear 13 of the auxiliary motor according to the working conditions to transmit and disengage power, effectively realizing the decoupling of the auxiliary motor's power and avoiding energy loss due to dragging of parts on the auxiliary motor side when the main motor works alone.

[0066] In this embodiment, the input shafts of the auxiliary motor 16 and the primary reduction drive gear 15 of the auxiliary motor are connected by a spline to transmit torque, and the second synchronizer 10 is fixedly connected to the driven gear shaft 11 of the primary reduction gear of the auxiliary motor by a spline connection.

[0067] Please refer to Figure 3 The dual-motor electric drive bridge configuration with main and auxiliary coordination also includes a first-gear driven gear 19 and a second-gear driven gear 20. The first-gear driven gear 19 and the second-gear driven gear 20 are fixed to both ends of the output shaft 18. The first-gear driven gear 19 meshes with the first-gear driving gear 6, and the second-gear driven gear 20 meshes with the second-gear driving gear 4 and the auxiliary motor secondary reduction driving gear 13, respectively.

[0068] Specifically, the driven gear 19 of gear I and the driven gear 20 of gear II are fixedly connected to both ends of the output shaft 18 via splines;

[0069] Furthermore, the main-auxiliary coordinated dual-motor electric drive bridge configuration also includes a three-stage planetary gear reducer shifting mechanism, a differential assembly, and a two-half-shaft structure; the three-stage planetary gear reducer shifting mechanism and the differential assembly are placed in the space between the main motor 1 and the auxiliary motor 16;

[0070] The three-stage planetary gear reducer includes a first support housing 21, a third synchronizer 23, a second support housing 24, a housing shifting assembly 25, an internal gear ring 26, an internal gear ring shifting assembly 37, and a planetary structure.

[0071] The first support housing 21 and the second support housing 24 (only part of them are shown, not all of them) are used to support the deceleration and shifting mechanism; the housing shifting assembly 25 is interference-fitted with the second support housing 24 so that the housing shifting assembly 25 can be fixed.

[0072] The planetary structure includes a planetary carrier shift assembly 22, planetary gears 27, a left supporting planetary carrier 28, planetary gear pins 29, a fourth needle roller bearing 30, a sun gear 35, and a right supporting planetary carrier 36. It should be noted that the number of planetary gears 27 can be configured according to torque requirements, and one of them is shown in Figure 4.

[0073] The right support planetary carrier 36 is rotatably sleeved on the output shaft. There is a gap between the two, and their movements are independent. Both the left support planetary carrier 28 and the right support planetary carrier 36 have holes into which planetary gear pins 29 are inserted. The left support planetary carrier 28 and the right support planetary carrier 36 are connected by planetary gear pins 29 and jointly support the rotation of planetary gear 27. The fourth needle roller bearing 30 is installed between planetary gear 27 and planetary gear pin 29. The sun gear 35, planetary gear 27 and internal gear ring 26 mesh with each other.

[0074] The planetary carrier shift assembly 22 is fixed on the right supporting planetary carrier 36. The internal gear ring shift assembly 37 is disposed on the internal gear ring 26. The internal gear ring shift assembly 37 and the movable third synchronizer 23 are constantly engaged. A shift fork is provided on the third synchronizer 23. The shift fork slides left and right to engage with the planetary carrier shift assembly 22 or the housing shift assembly 25. In the figure, the third synchronizer 23 moves to the left to engage with the planetary carrier shift assembly 22, and moves to the right to engage with the housing shift assembly 25. When the third synchronizer 23, the internal gear ring shift assembly 37, and the planetary carrier shift assembly 22 are engaged simultaneously, this is the high gear of the planetary gear set, with a speed ratio of 1. When the third synchronizer 23, the internal gear ring shift assembly 37, and the housing shift assembly 25 are engaged simultaneously, this is the low gear of the planetary gear set, with a speed ratio of 3.

[0075] The differential assembly includes a differential 31, a first differential bevel gear 33, and a second differential bevel gear 34. The two-half-shaft structure includes a left half-shaft 17 and a right half-shaft 32. The housing of the differential 31 is fixedly connected to the left supporting planetary carrier 28. The first differential bevel gear 33 is connected to the left half-shaft 17, and the second differential bevel gear 34 and right half-shaft 32 are all connected by splines. Power comes from the planetary carrier to the differential housing and is transmitted to the half-shafts through the differential. After the power is output through the left supporting planetary carrier 28, since the left supporting planetary carrier 28 is fixedly connected to the differential 31 housing by bolts, the power is split in the differential to the first differential bevel gear 33 and the second differential bevel gear 34 on both sides and then transmitted to the left half-shaft 17 and the right half-shaft 32 to drive the wheels.

[0076] like Figure 4 The diagram shows the principle of the dual-motor electric drive bridge configuration. This invention adopts a layout concept of multiple gears on the parallel shaft combined with multiple gears on the planetary gear set, as well as a layout concept that combines compactness and reliability. The main motor has two gears on the parallel shaft × two gears on the planetary gear set = four forward gears. Of course, it is not limited to this. Multiple gears can be set by setting multiple first synchronizers on the main motor, and multiple three-stage planetary gear set reduction and shifting mechanisms can be set. Each three-stage planetary gear set reduction and shifting mechanism can set multiple gears. The gears can be increased according to the multiplicative relationship as needed, and the gear selection is strong.

[0077] The following example uses a two-speed configuration, integrating the planetary gear shifting mechanism and differential assembly with the output shaft, placing the entire assembly between the main and auxiliary motors. This approach, while ensuring multiple gears meet operational requirements, also shortens the axial space, enabling a four-speed mode for the vehicle. Figure 5 As shown, the specific working principle is as follows:

[0078] like Figure 6As shown, when the first synchronizer 5 engages with the first gear drive gear 6 on the left and the third synchronizer 23 of the planetary gear shift mechanism engages with the housing shift assembly 25 on the right, (the auxiliary motor 16 joins or disengages through the second synchronizer 10 according to torque requirements), the power system has a speed ratio at this time, which is the first gear, and can be used for vehicle starting or climbing steep slopes with full load.

[0079] like Figure 7 As shown, when the first synchronizer 5 engages with the second gear drive gear 4 on the right, and the third synchronizer 23 of the planetary gear shift mechanism engages with the housing shift assembly 25 on the right (the auxiliary motor 16 joins or disengages through the second synchronizer 10 according to torque requirements), the power system has another speed ratio, which is the second gear, and can be used to drive the vehicle to cruise at low and medium speeds.

[0080] like Figure 8 As shown, when the first synchronizer 5 engages with the first gear drive gear 6 on the left, and the third synchronizer 23 of the planetary gear shift mechanism engages with the planetary carrier shift assembly 22 on the left (the auxiliary motor joins or disengages through the second synchronizer 10 according to torque requirements), the power system has a third speed ratio, which is the third gear, and can be used to drive the vehicle for medium and high speed cruising.

[0081] like Figure 9 As shown, when the first synchronizer 5 engages the second gear drive gear 4 on the right and the third synchronizer 23 of the planetary gear shift mechanism engages the planetary carrier shift assembly 22 on the left (the auxiliary motor joins or disengages through the second synchronizer 10 according to torque requirements), the power system has the last speed ratio, which is the fourth gear, and can be used to drive the vehicle to cruise at high speed.

[0082] Throughout the four gear shifts, the main motor can always operate within its efficient mid-range speed by selecting appropriate gear ratios. When the main motor's torque is insufficient to meet vehicle demands, the optional auxiliary motor can promptly supplement it, preventing the main motor from overloading and causing efficiency drops. Furthermore, while there is a brief power interruption when shifting from second to third gear, the vehicle speed is already relatively high in this shift range, resulting in minimal and acceptable shift shock. Shifts between other gears can be seamless thanks to the pre-adjusted auxiliary motor, significantly improving ride comfort, especially during low-gear shifts.

[0083] The present invention has a clear division of labor between the main and auxiliary motors. The four gears are mainly for the main motor, so that the main motor can work in a wider range of high-efficiency speeds, resulting in better overall efficiency. It avoids the frequent start-stop of the motor when switching gears back and forth between the two motors, which greatly reduces the efficiency and service life of the motor. The gears of the present invention have a multiplicative relationship, which has greater scalability in a limited space.

[0084] The following are various operating modes of the power system and their shifting and energy control strategies in the embodiments of the present invention. When developing the strategy in the drive mode, the operating torque of the two motors is coordinated and controlled based on the optimal efficiency of the electric drive system. The theoretical guiding formula is as follows:

[0085] ,

[0086] ,

[0087] ,

[0088] ,

[0089] ,

[0090] in, The desired operating torque allocated to the main motor, in N·m; The desired operating torque allocated to the auxiliary motor, in N·m; T out This refers to the output shaft torque. The planetary gear reducer (three-stage reduction) ratio is given; T is the current torque requirement of the vehicle; n1 is the current speed of the main motor in rpm; n2 is the current speed of the auxiliary motor in rpm; η 1、 η2 represents the efficiency of the main motor and auxiliary motor at corresponding torque and speed, including motor efficiency and motor controller efficiency; P represents the operating torque of the main motor, T, provided the vehicle operates at speed n and the required torque T. 主 The working torque of the auxiliary motor is T 辅 At that time, the power output of the entire electric drive axle assembly is given in kW. It is also assumed that the main motor's efficient speed range is [a, b] and the maximum torque that can be generated within this range is T. max The critical point for switching operating modes corresponds to the throttle depth K; the vehicle's real-time torque requirements. .

[0091] Based on the above theory, when the vehicle speed is n and the required torque is T q At that time, by controlling the operating torque of the main motor and the operating torque of the auxiliary motor The power distribution is optimized to minimize the output power of the electric drive axle assembly while meeting the overall vehicle requirements. This achieves optimal efficiency and energy saving for the electric drive axle assembly, and the torque distribution scheme between the two motors is considered the optimal solution. However, this basic strategy needs to be constrained and optimized based on actual operating conditions and the performance parameters of the electric drive axle assembly. This is because the main motor can efficiently meet the vehicle's power needs in many situations, and it is also necessary to avoid frequent intervention of the auxiliary motor. Therefore, the following constraint rules are set for use in conjunction:

[0092] Auxiliary motor intervention delay: To avoid frequent starts and stops of the auxiliary motor when there are slight torque fluctuations or throttle depth errors exceeding the critical throttle depth K corresponding to the working mode switching point, a short delay and torque hysteresis are set. Only when the high torque demand stabilizes for a certain period of time (set as...) will the auxiliary motor engage. Only then can the auxiliary motor be commanded to connect.

[0093] Main motor priority principle: When optimizing torque allocation, under the premise of meeting demand and overall efficiency, priority is given to ensuring the torque request of the main motor. The auxiliary motor is used as a supplement rather than an equal, so that the main motor can be engaged more naturally when switching back to single motor mode.

[0094] After theoretical analysis and preliminary constraints, the intelligent control strategy under the driving mode is described. Its core control strategy mainly adopts a three-layer control architecture of "decision layer - allocation layer - execution layer".

[0095] Specifically, the steps include the following:

[0096] Step 1: Obtain real-time vehicle status and operation data, and analyze the current operating condition of the vehicle based on the real-time status and operation data;

[0097] In this embodiment, the real-time vehicle status data obtained specifically includes throttle opening and rate of change; vehicle speed and rate of change of vehicle speed; main motor and auxiliary motor speeds; main and auxiliary motor temperatures and inverter temperatures; battery SOC, SOH and maximum allowable discharge power; current gear and synchronizer position; and the required driving torque Tq for the entire vehicle.

[0098] The current operating condition of the vehicle, as determined by real-time status data analysis, specifically includes:

[0099] When the required driving torque Tq of the whole vehicle is small and changes smoothly, the vehicle is in a light-load cruising condition.

[0100] When the required driving torque Tq of the whole vehicle is moderate and continues to increase, the vehicle is in a medium-load acceleration condition.

[0101] When the required driving torque Tq of the whole vehicle is greater than or equal to the maximum output capacity of the main motor, the vehicle is in a high-load acceleration / climbing condition.

[0102] When the vehicle speed is greater than or equal to the preset high-speed threshold Vh, the vehicle is in high-speed cruising mode.

[0103] Other special operating conditions include: high motor temperature, limited battery power, and low adhesion conditions.

[0104] Step 2: Determine the motor drive mode based on the vehicle's real-time operating data, and in each drive mode, use the corresponding motor drive control strategy to output the drive torque allocated to the motor.

[0105] In this embodiment, the motor drive modes include a single motor drive mode and a main-auxiliary cooperative dual motor drive mode.

[0106] The specific criteria for judgment are:

[0107] If the required driving torque Tq of the whole vehicle is less than or equal to the maximum efficient output torque of the main motor in the current gear, the temperature of the main motor is lower than the first temperature threshold T1, the battery SOC is within the set normal working range and the throttle opening change is less than the set threshold, then the single motor efficient drive mode of the main motor is adopted.

[0108] If the required driving torque Tq of the whole vehicle is greater than the maximum sustainable output torque of the main motor in the current gear, the temperature of the main motor exceeds the first temperature threshold T1, or the throttle opening change rate dAPS exceeds the threshold d0, then the main and auxiliary coordinated dual motor drive mode is adopted.

[0109] In each driving mode, a corresponding motor drive control strategy is adopted, specifically including:

[0110] In the main motor single-motor high-efficiency drive mode, the second synchronizer 10 is disconnected, the auxiliary motor 16 is disengaged, and the auxiliary motor is decoupled from the transmission system; the auxiliary motor torque is set to 0; the main motor is driven independently, and the main motor operating point remains in the high-efficiency region; this mode covers most daily operating conditions and has the lowest energy loss.

[0111] In the dual-motor drive mode with main and auxiliary motors working in tandem, the control of the second synchronizer 10 is activated by adjusting the operating torque of the main motor. and the operating torque of the auxiliary motor The power is allocated so that the power output of the electric drive axle assembly is minimized while meeting the driving torque required by the whole vehicle.

[0112] Furthermore, in the main-auxiliary coordinated dual-motor drive mode, the second synchronizer 10 is engaged to control the working torque of the main motor. and the operating torque of the auxiliary motor The torque distribution is performed such that the power output of the electric drive axle assembly is minimized while meeting the required driving torque for the entire vehicle. The torque distribution logic is a globally optimal distribution based on the efficiency MAP. This is done according to the obtained efficiency MAPs η1 and η2 of the main motor and auxiliary motor, and based on T... 主 ×n1 / 9550 / η1+T 辅 The theoretical calculation of ×n2 / 9550 / η2=P, for any total demand torque T q Online calculation of all satisfied Calculate the total output power P of the system from the combinations, and select the one that minimizes P. This optimization requires real-time dynamic weight adjustment, taking into account factors such as battery SOC and motor temperature to adjust for a more efficient combination.

[0113] Step 3: Determine whether a gear shift is needed, and based on the driving torque allocated to the output motor and the gear shifting strategy, switch to the corresponding gear;

[0114] When dealing with shift control without power interruption, the core strategy is to fully utilize the auxiliary motor to achieve shifting without power interruption. However, for shift control with power interruption (for 2-3 gears, i.e., planetary gear shifting), the high-speed response of the motor can be utilized to allow the main motor to actively adjust its speed during shifting to match the synchronous speed of the new gear, thereby reducing shift shock and time.

[0115] Specifically, the steps include the following:

[0116] Step 301: Determine whether a gear shift is required and the type of gear shift;

[0117] In this embodiment, a shift command is issued if any of the following conditions are met;

[0118] The main motor speed deviates from the high-efficiency range;

[0119] As the vehicle speed continued to increase, the main motor reached its maximum speed.

[0120] The vehicle needs to enter a high-speed cruising or high-torque acceleration range;

[0121] The motor temperature needs to be reduced to allow it to operate in a higher efficiency range.

[0122] It should be noted that the specific type of gear shift needs to be determined based on the issued gear shift command, such as whether it is upshifting or downshifting, which gear to upshift to, and which gear to downshift to. This can be achieved using existing judgment logic, which is not the focus of this application, so it will not be explained in detail.

[0123] Step 302: Execute the corresponding shift strategy according to the different shift types to switch to the target gear;

[0124] The shifting between 1 / 2 gear and 3 / 4 gear can be achieved without power interruption by supplementing the power of the auxiliary motor; however, the shifting between 2 / 3 gear will result in power interruption due to structural limitations.

[0125] The specific gear positions corresponding to the synchronizer engagement states are shown in Table 1:

[0126] Table 1. Gear Relationships Corresponding to Synchronizer Engagement States

[0127]

[0128] In this embodiment, if the type of gear shift is a non-powered interrupted gear shift, it includes the interchange of gears between 1st and 2nd gear, and between 3rd and 4th gear;

[0129] During the gear shift preparation phase, the auxiliary motor is instructed to engage or its torque is slightly increased to share part of the total torque. During the gear shift execution phase, the main motor torque drops rapidly to zero. At this time, the vehicle power is entirely maintained by the auxiliary motor. Synchronizer I is connected to the designated gear. When the gear shift ends, the main motor quickly increases the torque to the target value in the new gear, while the auxiliary motor torque smoothly decreases to the optimized distribution value or disengages.

[0130] Specifically, when the shift type is a power-interrupted shift, the third synchronizer remains unchanged, and the second synchronizer determines its current state, which may be engaged or disengaged. If the shift is engaged, the second synchronizer remains unchanged and continues to provide power to achieve a power-interrupted shift. If the shift is disengaged, it needs to be engaged to achieve a power-interrupted shift. The first synchronizer is controlled to connect to the designated gear.

[0131] For example, when shifting from 1st to 2nd gear, while the third synchronizer of the planetary gear shifting mechanism is engaged with the right-hand housing shifting assembly, the second synchronizer determines its current state, which may be engaged or disengaged. If it is engaged during the shift, the second synchronizer remains unchanged, continuing to provide power to achieve unpowered shifting. If it is disengaged, it needs to be engaged to achieve unpowered shifting. The first synchronizer is controlled to change from its original left-hand engaged 1st gear drive gear to its right-hand engaged 2nd gear drive gear, outputting the second speed ratio.

[0132] If the shift type is a power interruption shift, including the switch between 2nd and 3rd gear, the main motor actively adjusts its speed during the shift to match the synchronous speed of the new gear, taking advantage of the high-speed response of the motor, thus reducing shift shock and time.

[0133] Specifically, when the shift type is power interruption shift, the first synchronizer and the third synchronizer are simultaneously connected to the designated gear, and the dual-motor cooperative or single-motor mode is restored after the shift.

[0134] For example, when shifting from 2nd gear to 3rd gear, the first synchronizer right engages with the 2nd gear drive gear, and the third synchronizer right engages with the housing shift assembly of the planetary gear shift mechanism, which is changed to the first synchronizer left engages with the 1st gear drive gear, and the third synchronizer left engages with the planetary carrier shift assembly of the planetary gear shift mechanism.

[0135] Step 4: Determine the motor braking mode based on the vehicle's real-time operating data, and match the braking energy recovery strategy according to the motor braking mode;

[0136] Braking energy recovery strategy; Similar to the intelligent control strategy in drive mode, the braking energy recovery strategy also adopts a three-layer control architecture of "decision layer - allocation layer - execution layer".

[0137] First, the decision-making level uses information such as brake pedal depth and travel rate, vehicle speed, battery SOC, motor temperature, and current gear input from sensors to determine whether the braking intensity is light, moderate, or emergency braking, and to determine the system's maximum regenerative power.

[0138] The decision-making layer determines the ratio of motor braking to mechanical braking. It identifies whether the braking type is emergency braking or non-emergency braking. In emergency braking, mechanical braking is used exclusively; in non-emergency braking, the decision is made to proceed to the allocation layer. To avoid frequent intervention of the auxiliary motor, braking energy recovery only considers the allocation under the current mode. That is, in single-motor drive mode, the main motor mechanical braking allocates braking force; in dual-motor operation mode, the allocation is between the dual motors and mechanical braking. This allocation strategy allows for smoother mode switching between drive and braking, greatly increasing braking safety.

[0139] While ensuring sufficient braking force, the system maximizes the proportion of electric motor braking to improve fuel economy. Similarly, if the system is in dual-motor cooperative mode, the torque distribution logic, like the drive strategy, is a globally optimal allocation based on the efficiency MAP. Finally, at the decision-making level, motor torque control commands are sent to the controllers of the main and auxiliary motors, strictly controlling the rate of torque change to ensure smooth braking and avoid shocks. In addition, for main motor regenerative braking conditions, especially during continuous braking conditions such as long downhill slopes, the system can actively downshift the main motor, increasing its speed and moving it from a low-efficiency, low-speed range to a high-efficiency, medium-to-high-speed power generation range, thereby significantly improving its regenerative power and capacity.

[0140] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A dual-motor electric drive bridge configuration with main and auxiliary motors, comprising a main motor and a gear shaft system matched with the main motor, an auxiliary motor and a gear shaft system matched with the auxiliary motor, and an output shaft assembly; wherein, The main motor and its matching gear shaft system, as well as the auxiliary motor and its matching gear shaft system, are arranged in a mirror-symmetrical manner with the output shaft assembly as the center. The configuration further includes a controller and at least one three-stage planetary gear reducer shifting mechanism. The gear shaft system matched with the main motor includes at least one first synchronizer, and the gear shaft system matched with the auxiliary motor includes at least one second synchronizer. Each three-stage planetary gear reducer shifting mechanism includes at least one third synchronizer and a planetary gear reduction mechanism. Each first synchronizer, second synchronizer, and third synchronizer is equipped with a shift fork, and the state of the shift fork is controlled by the controller. The highest gear of the main motor is located close to the main motor side. The auxiliary motor forms a three-tooth meshing structure with the highest gear of the main motor, which shortens the axial distance of the auxiliary motor's output shaft and reduces the coupling cost between the auxiliary and main motors. The auxiliary motor only needs a lower speed to match the full speed of the main motor, reducing speed fluctuations of the auxiliary motor and providing a faster intervention response. The controller is configured to: based on the collected real-time vehicle status operating data and motor drive mode, output the allocated drive torque of the motor using a corresponding motor drive control strategy in each drive mode; determine whether a gear shift is needed; if so, based on the output allocated drive torque of the motor and the gear shifting strategy, control the shift forks of each synchronizer to switch to achieve multi-gear switching. Based on the drive torque allocated to the output motor and the shifting strategy, the system switches to the corresponding gear, including: When the first synchronizer engages the I gear drive gear on the left and the third synchronizer of the planetary gear shifting mechanism engages the housing shifting assembly on the right, the auxiliary motor joins or disengages through the second synchronizer according to the torque requirement, outputting the first speed ratio as the first gear; When the first synchronizer engages the second gear drive gear on the right, and the third synchronizer of the planetary gear shifting mechanism engages the housing shifting assembly on the right, the auxiliary motor joins or disengages through the second synchronizer according to the torque requirement, outputting the second speed ratio as the second gear; When the first synchronizer engages the first gear drive gear on the left, and the third synchronizer of the planetary gear shifting mechanism engages the planetary carrier shifting assembly on the left, the auxiliary motor joins or disengages through the second synchronizer according to torque requirements, outputting the third speed ratio as the third gear; When the first synchronizer engages the second gear drive gear on the right and the third synchronizer of the planetary gear shifting mechanism engages the planetary carrier shifting assembly on the left, the auxiliary motor joins or disengages through the second synchronizer according to torque requirements, outputting the fourth speed ratio as the fourth gear.

2. The dual-motor electric drive bridge configuration with main and auxiliary motors as described in claim 1, characterized in that, The gear shaft system matched with the main motor also includes a main motor reduction mechanism, a first-gear drive gear, and a second-gear drive gear. The main motor reduction mechanism includes a main motor first-stage reduction driven gear shaft, a main motor first-stage reduction drive gear, and a main motor first-stage reduction driven gear. The main motor first-stage reduction drive gear is connected to the input shaft of the main motor. The main motor first-stage reduction driven gear is fixed to the main motor first-stage reduction driven gear shaft. The main motor first-stage reduction driven gear and the main motor first-stage reduction drive gear mesh. The first synchronizer selectively engages with the first-gear drive gear or the second-gear drive gear according to the working conditions to achieve power transmission and gear selection.

3. The dual-motor electric drive bridge configuration with main and auxiliary motors as described in claim 1, characterized in that, The gear shaft system matched with the auxiliary motor also includes an auxiliary motor reduction mechanism. This mechanism comprises a primary reduction driven gear shaft, a primary reduction driven gear, a primary reduction driving gear, and a secondary reduction driving gear. The primary reduction driven gear is fixed to the primary reduction driven gear shaft. The primary reduction driving gear is connected to the input shaft of the auxiliary motor, and the primary reduction driven gear meshes with it. The second synchronizer engages or disengages with the secondary reduction driving gear according to operating conditions to transmit and disengage power. The gear shaft system matched with the auxiliary motor also includes a third needle roller bearing, through which the secondary reduction driving gear is mounted to the primary reduction driven gear shaft.

4. The dual-motor electric drive bridge configuration with main and auxiliary motors as described in claim 1, characterized in that, The three-stage planetary gear reducer also includes a left supporting planetary carrier, a right supporting planetary carrier, a sun gear, planetary gears, and an internal gear ring. Both the left and right supporting planetary carriers have holes into which planetary gear pins are inserted. The left and right supporting planetary carriers are connected by planetary gear pins to jointly support the rotation of the planetary gears. Needle roller bearings are installed between the planetary gears and planetary gear pins. The sun gear, planetary gears, and internal gear ring mesh with each other.

5. The dual-motor electric drive bridge configuration with main and auxiliary motors as described in claim 1, characterized in that, In each drive mode, a corresponding motor drive control strategy is used to output the drive torque allocated to the motor, including: In the single-motor high-efficiency drive mode of the main motor, the control second synchronizer is disconnected, the auxiliary motor is disengaged, the auxiliary motor is decoupled from the transmission system, and the main motor is driven independently. In the dual-motor drive mode with main and auxiliary motors working in tandem, the control of the second synchronizer is activated by adjusting the operating torque of the main motor. and the working torque of the auxiliary motor The power output of the electric drive axle assembly is minimized while still meeting the required driving torque for the entire vehicle.

6. A control method for a dual-motor electric drive bridge configuration with primary and secondary cooperative operation, employing a dual-motor electric drive bridge configuration with primary and secondary cooperative operation as described in any one of claims 1-5, characterized in that, Includes the following steps: Obtain real-time vehicle status and operating data; The motor drive mode is determined based on the real-time vehicle status data. In each drive mode, the corresponding motor drive control strategy is adopted to output the drive torque allocated to the motor. Determine whether a gear shift is needed. If so, based on the driving torque allocated to the output motor and the gear shifting strategy, control the shift forks of each synchronizer to switch to achieve multi-gear switching. Based on the drive torque allocated to the output motor and the shifting strategy, the system switches to the corresponding gear, including: When the first synchronizer engages the first gear drive gear on the left and the third synchronizer of the planetary gear shifting mechanism engages the housing shifting assembly on the right, the auxiliary motor joins or disengages through the second synchronizer according to the torque requirement, outputting the first speed ratio as the first gear; When the first synchronizer engages the second gear drive gear on the right, and the third synchronizer of the planetary gear shifting mechanism engages the housing shifting assembly on the right, the auxiliary motor joins or disengages through the second synchronizer according to the torque requirement, and outputs the second speed ratio as the second gear; When the first synchronizer engages the first gear drive gear on the left, and the third synchronizer of the planetary gear shifting mechanism engages the planetary carrier shifting assembly on the left, the auxiliary motor joins or disengages through the second synchronizer according to torque requirements, outputting the third speed ratio as the third gear; When the first synchronizer engages the second gear drive gear on the right and the third synchronizer of the planetary gear shifting mechanism engages the planetary carrier shifting assembly on the left, the auxiliary motor joins or disengages through the second synchronizer according to torque requirements, outputting the fourth speed ratio as the fourth gear.

7. The control method for a dual-motor electric drive bridge configuration with main and auxiliary motors as described in claim 6, characterized in that, The method further includes determining the motor braking mode based on real-time vehicle operating data, and matching a braking energy recovery strategy according to the motor braking mode, including: It receives sensor inputs such as brake pedal depth, brake pedal travel rate, vehicle speed, battery SOC, motor temperature, and current gear information, and determines the braking intensity level and the maximum regenerative power of the system accordingly. The ratio of motor braking to mechanical braking is determined based on the output braking intensity level and the maximum regenerative power. If the braking is identified as an emergency braking, mechanical braking is used entirely. If the braking is identified as a non-emergency braking, the braking force is distributed according to the current driving mode: in single-motor driving mode, braking force is distributed between the main motor and mechanical braking; in dual-motor operating mode, braking force is distributed between the dual motors and mechanical braking.

8. The control method for a dual-motor electric drive bridge configuration with main and auxiliary motors as described in claim 6, characterized in that, Motor drive modes include single-motor drive mode and main-auxiliary coordinated dual-motor drive mode; the specific criteria for judgment are: If the required driving torque Tq of the whole vehicle is less than or equal to the maximum efficient output torque of the main motor in the current gear, the temperature of the main motor is lower than the first temperature threshold T1, the battery SOC is within the set normal working range and the throttle opening change is less than the set threshold, then the single motor efficient drive mode of the main motor is adopted. If the required driving torque Tq of the whole vehicle is greater than the maximum sustainable output torque of the main motor in the current gear, the temperature of the main motor exceeds the first temperature threshold T1, or the throttle opening change rate exceeds the threshold, then the main and auxiliary coordinated dual motor drive mode is adopted.

Images