Dual-motor drive gearbox structure and control method thereof

Abstract

The application relates to a double-motor driving gearbox structure and a control method thereof, which comprises a first power mechanism, a second power mechanism, a sub-gearbox confluence mechanism and a sub-gearbox output mechanism. The first power mechanism comprises a first driving motor and a first input shaft, two sets of gear pairs on the first input shaft and a first gear shifting execution mechanism for selectively locking the two sets of gear pairs. The second power mechanism comprises a second driving motor and a second input shaft, two sets of gear pairs on the second input shaft and a second gear shifting execution mechanism for selectively locking the two sets of gear pairs. The sub-gearbox confluence mechanism comprises a planetary gear mechanism and a main gearbox output shaft sleeved in a sun gear, and the two sets of gear pairs are respectively in transmission connection with the main gearbox output shaft and the sun gear. The sub-gearbox output mechanism comprises a rear sub-gearbox, wherein the rear sub-gearbox is internally provided with a sub-gearbox output shaft coaxially connected with the main gearbox output shaft, the sub-gearbox output shaft is in transmission connection with a planetary carrier, and an inner ring is fixedly connected with the rear sub-gearbox. The application can realize uninterrupted gear shifting power and greatly improves gear shifting comfort.

Description

Technical Field

[0001] This application relates to the field of electric drive powertrain technology, and in particular to a dual-motor drive gearbox structure and its control method. Background Technology

[0002] With the development of the automotive industry, the pure electric drive technology for heavy commercial vehicles has ushered in a period of rapid development. Pure electric drive AMT transmissions used for central drive and electric drive axles with AMT transmissions integrated on the drive axle are the two main existing technical routes.

[0003] In related technologies, electric drive transmission solutions for heavy vehicles are usually driven by a low-speed single motor, and the single motor is coaxial with the output shaft. In the process of shifting gears, the drive motor needs to cooperate with the transmission to clear torque and adjust speed. There will inevitably be a power interruption during gear shifting, which will affect the comfort of the vehicle. Moreover, the power interruption in harsh working conditions such as mining areas and climbing long slopes will seriously affect driving safety.

[0004] Therefore, how to solve the unavoidable power interruption problem during gear shifts in existing electric drive systems, while meeting the requirements of vehicle layout, and achieving a simple structure and low cost, has become an important technical challenge that urgently needs to be addressed by those skilled in the art. Summary of the Invention

[0005] This application provides a dual-motor drive gearbox structure and its control method to solve the problem of unavoidable power interruption during gear shifting in existing electric drive systems.

[0006] The first aspect of this application provides a dual-motor drive gearbox structure, including: The first power mechanism includes a first drive motor, a first input shaft connected to the output end of the first drive motor, two sets of gear pairs on the first input shaft, and a first shifting actuator for selectively locking the two sets of gear pairs. The second power mechanism includes a second drive motor, a second input shaft connected to the output end of the second drive motor, two sets of gear pairs located on the second input shaft, and a second shifting actuator for selectively locking the two sets of gear pairs; The auxiliary gearbox merging mechanism includes a planetary gear mechanism consisting of a planet carrier, a sun gear and an internal gear ring, and a main gearbox output shaft that is loosely fitted inside the sun gear. The two sets of gear pairs on the first input shaft and the two sets of gear pairs on the second input shaft are respectively connected to the main gearbox output shaft and the sun gear for transmission. The auxiliary gearbox output mechanism includes a rear auxiliary gearbox, wherein an auxiliary gearbox output shaft is provided inside the rear auxiliary gearbox and coaxially connected to the output shaft of the main gearbox. The auxiliary gearbox output shaft is drivenly connected to the planetary carrier, and the internal gear ring is fixedly connected to the rear auxiliary gearbox.

[0007] In some implementations: the second power mechanism further includes a high-low gear switching mechanism, which includes a third input shaft connected to the output end of the second drive motor. The second input shaft and the third input shaft are coaxially arranged, and the third input shaft is located between the second drive motor and the second input shaft. An intermediate shaft is provided parallel to the second input shaft and the third input shaft. A first gear pair is provided between the third input shaft and the intermediate shaft, and a second gear pair is provided between the second input shaft and the intermediate shaft. A third shifting actuator is provided on the second input shaft for selectively locking the first gear pair and the second gear pair.

[0008] In some implementations: the output end of the intermediate shaft is connected to a PTO power take-off unit, the first gear pair includes a first driving gear and a first driven gear meshing with each other, the first driving gear is fixed on the third input shaft, and the first driven gear is fixed on the intermediate shaft; The second gear pair includes a second driving gear and a second driven gear that mesh with each other. The second driving gear is fixed on the intermediate shaft, and the second driven gear is loosely fitted on the second input shaft. The third shifting actuator is used to selectively lock the first driving gear and the second driven gear.

[0009] In some implementations: the two sets of gear pairs on the first input shaft respectively include a third driving gear and a fourth driving gear that are loosely fitted on the first input shaft, a third driven gear that is fixed on the main output shaft and meshed with the third driving gear, and a fourth driven gear that is fixed on the sun gear and meshed with the fourth driving gear; The two sets of gear pairs on the second input shaft include a fifth driving gear and a sixth driving gear that are respectively loosely fitted on the second input shaft. The fifth driving gear is meshed with the third driven gear, and the sixth driving gear is meshed with the fourth driven gear.

[0010] In some implementations: a hollow shaft for connecting the sun gear is loosely fitted on the main output shaft; the fourth driven gear is fixed on the hollow shaft; the fourth driven gear and the hollow shaft are fitted with a clearance fit via internal and external splines; and the third driven gear and the main output shaft are fitted with a clearance fit via internal and external splines.

[0011] In some implementations: the number of teeth of the third driving gear is different from the number of teeth of the fifth driving gear, so that the speed ratio of the third driving gear to the third driven gear is different from the speed ratio of the fifth driving gear to the third driven gear; The number of teeth of the fourth driving gear may be the same as or different from the number of teeth of the sixth driving gear, so that the speed ratio of the fourth driving gear to the fourth driven gear is different from the speed ratio of the sixth driving gear to the fourth driven gear.

[0012] In some implementations: the auxiliary gearbox output mechanism further includes a disengagement mechanism fixed on the auxiliary gearbox output shaft for engaging or disengaging the planetary carrier. When the rotational speeds of the fourth and sixth drive gears reach a set threshold, the disengagement mechanism disengages from the planetary carrier.

[0013] A second aspect of this application provides a control method for a dual-motor drive gearbox structure, the method using the dual-motor drive gearbox structure described in any of the above embodiments, the method comprising: Obtain the vehicle's driving status parameters, which include at least vehicle speed and load requirements; The target gear and target operating mode are determined based on the driving status parameters. When a gear shift is detected as needed and the vehicle is in drive mode, a power-uninterrupted gear shift strategy is implemented: Control the first drive motor to maintain the current gear and output drive torque; Control the second drive motor to reduce the output torque to a preset threshold, and control the second shift actuator to switch gears; After the second gear shifting actuator completes the gear shift, it controls the second drive motor to resume torque output and controls the first drive motor to perform gear shifting or maintain the current state. Throughout the gear shifting process, the auxiliary gearbox output shaft always receives drive torque from at least one of the first drive motor or the second drive motor.

[0014] In some implementations: the target operating mode includes multiple modes such as single-motor drive mode, dual-motor drive mode, driving charging mode, and parking power generation mode; The method further includes switching between the multiple working modes according to the vehicle speed and load requirements, wherein in the single motor drive mode, only one of the first drive motor or the second drive motor is turned on, while the other is in an idling or stopped state.

[0015] In some implementations: when executing the power-uninterrupted shifting strategy, a torque smoothing transition step is also included: during the process of the second drive motor restoring torque output, the torque of the second drive motor is linearly increased, while the torque of the first drive motor is linearly decreased, until the torque distribution between the two reaches the target ratio.

[0016] The beneficial effects of the technical solution provided in this application include: This application provides a dual-motor drive gearbox structure and its control method. The dual-motor drive gearbox structure of this application is provided with a first power mechanism, which includes a first drive motor, a first input shaft connected to the output end of the first drive motor, two sets of gear pairs on the first input shaft, and a first shifting actuator for selectively locking the two sets of gear pairs; and a second power mechanism, which includes a second drive motor, a second input shaft connected to the output end of the second drive motor, two sets of gear pairs located on the second input shaft, and a second shifting actuator for selectively locking the two sets of gear pairs. The auxiliary gearbox merging mechanism includes a planetary gear mechanism consisting of a planetary carrier, a sun gear, and an internal gear ring, as well as a main gearbox output shaft loosely fitted inside the sun gear. Two sets of gear pairs on the first input shaft and two sets of gear pairs on the second input shaft are respectively connected to the main gearbox output shaft and the sun gear for transmission. The auxiliary gearbox output mechanism includes a rear auxiliary gearbox, in which an auxiliary gearbox output shaft coaxially connected to the main gearbox output shaft is provided. The auxiliary gearbox output shaft is connected to the planetary carrier for transmission, and the internal gear ring is fixedly connected to the rear auxiliary gearbox.

[0017] Therefore, the dual-motor drive gearbox structure of this application is configured with a first power mechanism and a second power mechanism arranged in parallel. The auxiliary gearbox merging mechanism is configured with a main gearbox output shaft and a planetary gear mechanism that are driveably connected to the first and second power mechanisms. The output ends of the main gearbox output shaft and the planetary gear mechanism are fixedly connected to the auxiliary gearbox output shaft. The first drive motor and the second drive motor can drive the main gearbox output shaft and the planetary gear mechanism to rotate separately or simultaneously. Compared with a single motor with a reduction gearbox, this application can achieve uninterrupted power during gear shifting, greatly improving shifting comfort; and can match the torque output of the two motors in real time according to the wheel end torque required during vehicle operation, greatly improving fuel economy. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the structure of an embodiment of this application; Figure 2 This is a schematic diagram showing torque and vehicle speed under different modes in the embodiments of this application.

[0020] Figure label: 10. First power mechanism; 11. First drive motor; 12. First input shaft; 13. First gear shifting actuator; 14. Third drive gear; 15. Fourth drive gear; 16. Third driven gear; 17. Fourth driven gear; 20. Second power mechanism; 21. Second drive motor; 22. Second input shaft; 23. Second shifting actuator; 24. Fifth drive gear; 25. Sixth drive gear; 30. Auxiliary gearbox merging mechanism; 31. Sun gear; 32. Planetary carrier; 33. Internal gear ring; 34. Main gearbox output shaft; 35. Hollow shaft of the sun gear; 40. Auxiliary gearbox output mechanism; 41. Rear auxiliary gearbox; 42. Auxiliary gearbox output shaft; 43. Disengagement mechanism; 50. High / low gear switching mechanism; 51. Third input shaft; 52. Intermediate shaft; 53. Third gear shifting actuator; 54. First driving gear; 55. First driven gear; 56. Second driving gear; 57. Second driven gear; 58. PTO (Power Take-Off) unit. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0022] This application provides a dual-motor drive gearbox structure and its control method, which can solve the problem of unavoidable power interruption during gear shifting in existing electric drive systems.

[0023] See Figure 1 As shown, the first aspect of this application provides a dual-motor drive gearbox structure, including: The first power mechanism 10 includes a first drive motor 11, a first input shaft 12 connected to the output end of the first drive motor 11, two sets of gear pairs on the first input shaft 12, and a first shifting actuator 13 for selectively locking the two sets of gear pairs.

[0024] The second power mechanism 20 includes a second drive motor 21, a second input shaft 22 connected to the output end of the second drive motor 21, two sets of gear pairs located on the second input shaft 22, and a second shifting actuator 23 for selectively locking the two sets of gear pairs.

[0025] The auxiliary gearbox merging mechanism 30 includes a planetary gear mechanism consisting of a planet carrier 32, a sun gear 31, and an internal gear ring 33, as well as a main gearbox output shaft 34 loosely fitted inside the sun gear 31. Two sets of gear pairs on the first input shaft 12 are respectively connected to the main gearbox output shaft 34 and the sun gear 31 for transmission. Two sets of gear pairs on the second input shaft 22 are respectively connected to the main gearbox output shaft 34 and the sun gear 31 for transmission.

[0026] The auxiliary gearbox output mechanism 40 includes a rear auxiliary gearbox 41, which has an auxiliary gearbox output shaft 42 coaxially connected to the main gearbox output shaft 34. The auxiliary gearbox output shaft 42 is connected to the planetary carrier 32 for transmission, and the internal gear ring 33 is fixedly connected to the rear auxiliary gearbox 41.

[0027] The first drive motor 11 and the second drive motor 21 are respectively connected to the first input shaft 12 and the second input shaft 22; the power transmission paths of the first power mechanism 10 and the second power mechanism 20 are independent of each other, and both the first power mechanism 10 and the second power mechanism 20 are provided with two sets of gear pairs, as well as a shifting actuator for selectively locking the two sets of gear pairs.

[0028] The power from the first power mechanism 10 and the second power mechanism 20 is ultimately coupled to the output shaft 42 of the auxiliary gearbox through the auxiliary gearbox merging mechanism 30. When a gear shift is required, one of the drive motors is controlled to maintain the current gear and output drive torque, while the other drive motor is controlled to cooperate with its corresponding gear shifting actuator to switch gears. After the shift is completed, the torque is redistributed, thereby achieving uninterrupted power shifting.

[0029] The dual-motor drive gearbox structure of this application embodiment is provided with a first power mechanism 10 and a second power mechanism 20 arranged in parallel. The auxiliary gearbox merging mechanism 30 is provided with a main gearbox output shaft 34 and a planetary gear mechanism that are drively connected to the first power mechanism 10 and the second power mechanism 20.

[0030] The output ends of the main gearbox output shaft 34 and the planetary gear mechanism are fixedly connected to the auxiliary gearbox output shaft 42. The first drive motor 11 and the second drive motor 21 can drive the main gearbox output shaft 34 and the planetary gear mechanism to rotate separately or simultaneously. Compared with the arrangement of a single motor with a reduction gearbox, this application can achieve uninterrupted power shifting, greatly improving shifting comfort; and can match the torque output of the two motors in real time according to the wheel end torque required when the vehicle is driving, greatly improving economy.

[0031] In some alternative implementations: see Figure 1As shown, this application embodiment provides a dual-motor drive gearbox structure. The second power mechanism 20 of the dual-motor drive gearbox structure further includes a high / low gear switching mechanism 50. The high / low gear switching mechanism 50 includes a third input shaft 51 connected to the output end of the second drive motor 21. The second input shaft 22 and the third input shaft 51 are coaxially arranged, and the third input shaft 51 is located between the second drive motor 21 and the second input shaft 22.

[0032] An intermediate shaft 52 is arranged parallel to the second input shaft 22 and the third input shaft 51. A first gear pair is provided between the third input shaft 51 and the intermediate shaft 52, and a second gear pair is provided between the second input shaft 22 and the intermediate shaft 52. A third shifting actuator 53 for selectively locking the first gear pair and the second gear pair is provided on the second input shaft 22.

[0033] A PTO (Power Take-Off) device 58 is connected to the output end of the intermediate shaft 52. The first gear pair includes a first driving gear 54 and a first driven gear 55 meshing with each other. The first driving gear 54 is fixed on the third input shaft 51, and the first driven gear 55 is fixed on the intermediate shaft 52. The second gear pair includes a second driving gear 56 and a second driven gear 57 meshing with each other. The second driving gear 56 is fixed on the intermediate shaft 52, and the second driven gear 57 is loosely fitted on the second input shaft 22.

[0034] The third shift actuator 53 is used to selectively lock the first drive gear 54 and the second driven gear 57. When the third shift actuator 53 selectively locks the first drive gear 54, the power of the second drive motor 21 is transmitted to the second input shaft 22 after passing through the third input shaft 51, the first drive gear 54 and the third shift actuator 53 in sequence.

[0035] When the third shift actuator 53 selectively locks the second driven gear 57, the power of the second drive motor 21 is transmitted sequentially through the third input shaft 51, the first drive gear 54, the first driven gear 55, the intermediate shaft 52, the second drive gear 56, the second driven gear 57 and the third shift actuator 53, and then to the second input shaft 22.

[0036] In some alternative implementations: see Figure 1 As shown, this application embodiment provides a dual-motor drive gearbox structure. The two sets of gear pairs on the first input shaft 12 of the dual-motor drive gearbox structure include a third driving gear 14 and a fourth driving gear 15 respectively loosely fitted on the first input shaft 12, a third driven gear 16 fixed on the main gearbox output shaft 34 and meshing with the third driving gear 14, and a fourth driven gear 17 fixed on the sun gear 31 and meshing with the fourth driving gear 15.

[0037] The two gear pairs on the second input shaft 22 include a fifth driving gear 24 and a sixth driving gear 25, which are respectively loosely fitted on the second input shaft 22. The fifth driving gear 24 is meshed with the third driven gear 16, and the sixth driving gear 25 is meshed with the fourth driven gear 17.

[0038] A hollow sun gear shaft 35, which connects to the sun gear 31, is loosely fitted on the main output shaft 34. The fourth driven gear 17 is fixed on the hollow sun gear shaft 35. The fourth driven gear 17 and the hollow sun gear shaft 35 are fitted with a clearance through internal splines and external splines. The third driven gear 16 and the main output shaft 34 are fitted with a clearance through internal splines and external splines.

[0039] When the first drive motor 11 and the second drive motor 21 are driven, due to manufacturing tolerances, assembly errors, and stress deformation, the power from the first power mechanism 10 and the second power mechanism 20 is easily out of sync when it converges to the same auxiliary box output shaft 42, causing a "side load" phenomenon (i.e., the load is concentrated on one side of the spline teeth) in the traditional rigid spline connection. The internal spline and external spline clearance fit designed in this application allows the connecting parts to generate a small amount of self-adjustment (self-alignment) at the moment of stress, while ensuring the transmission of torque, thus releasing the additional stress caused by the asynchrony.

[0040] In some alternative implementations: see Figure 1 As shown in the embodiment of this application, a dual-motor drive gearbox structure is provided. The number of teeth on the third drive gear 14 is different from the number of teeth on the fifth drive gear 24, so that the speed ratio between the third drive gear 14 and the third driven gear 16 is different from the speed ratio between the fifth drive gear 24 and the third driven gear 16. The number of teeth on the fourth drive gear 15 is the same as or different from the number of teeth on the sixth drive gear 25, so that the speed ratio between the fourth drive gear 15 and the fourth driven gear 17 is different from the speed ratio between the sixth drive gear 25 and the fourth driven gear 17.

[0041] The embodiments of this application employ asymmetrical gear sets (i.e., the speed ratio of the third driving gear 14 to the third driven gear 16 is different from the speed ratio of the fifth driving gear 24 to the third driven gear 16, and the speed ratio of the fourth driving gear 15 to the fourth driven gear 17 is different from the speed ratio of the sixth driving gear 25 to the fourth driven gear 17), so that the speed ratios of the first power mechanism 10 and the second power mechanism 20 are misaligned, thereby expanding the coverage range of the total speed ratio (e.g., a larger span between low speed and high torque and high speed and low speed).

[0042] In some alternative implementations: see Figure 1As shown, this application embodiment provides a dual-motor drive gearbox structure. The auxiliary gearbox output mechanism 40 of the dual-motor drive gearbox structure also includes a disengagement mechanism 43 fixed on the auxiliary gearbox output shaft 42 for engaging or disengaging the planetary carrier 32. When the rotational speed of the fourth drive gear 15 and the sixth drive gear 25 reaches a set threshold, the disengagement mechanism 43 disengages the planetary carrier 32 to prevent the fourth drive gear 15 and the sixth drive gear 25 from overspeeding.

[0043] See Figure 2 As shown, by controlling the working modes of the first drive motor 11 and the second drive motor 21, and in conjunction with the first shift actuator 13, the second shift actuator 23, the third shift actuator 53 and the disengagement mechanism 43, the working modes shown in Table 1 can be formed.

[0044] Table 1: Working Modes of Dual-Motor Drive Gearbox Structure

[0045] Mode 1: Extreme Economy Mode, the first drive motor 11 drives the highest gear, with no drag loss from the intermediate shaft 52 and planetary gear mechanism.

[0046] Mode 2: Single motor power mode, the first drive motor 11 drives the second-highest gear, without the drag loss of the intermediate shaft 52.

[0047] Modes 3-6: The working mode of the second drive motor 21, with a small difference in the speed ratio of the four gears; among them, modes 4 and 6 have drag loss of the intermediate shaft 52, and are slightly less efficient than modes 1 and 2.

[0048] Modes 7-12: Dual motor operating modes, used for scenarios with high power requirements; among them, modes 9 and 11 are the second lowest dual motor settings, with mode 9 having stronger power; among them, modes 10 and 12 are the highest and second highest dual motor settings, with mode 12 having stronger power.

[0049] See Figure 1 As shown, a second aspect of this application provides a control method for a dual-motor drive gearbox structure. The method uses the dual-motor drive gearbox structure described in any of the above embodiments, and includes: Step 101: Obtain the vehicle's driving status parameters, which include at least vehicle speed and load requirements.

[0050] Step 102: Determine the target gear and target operating mode based on the driving status parameters. The target operating mode includes multiple modes such as single motor drive mode, dual motor drive mode, driving charging mode, and parking power generation mode.

[0051] Step 103: When a gear shift is detected and the vehicle is in drive mode, execute the power-uninterrupted gear shifting strategy: Step 104: Control the first drive motor 11 to maintain the current gear and output drive torque; Step 105: Control the second drive motor 21 to reduce the output torque to a preset threshold, and control the second shift actuator 23 to perform gear switching.

[0052] Step 106: After the second gear shifting actuator 23 completes the gear shifting, control the second drive motor 21 to restore torque output, and control the first drive motor 11 to perform gear shifting or maintain the current state.

[0053] Throughout the gear shifting process, the auxiliary gearbox output shaft 42 always receives drive torque from at least one of the first drive motor 11 or the second drive motor 21.

[0054] In some optional implementations: This application provides a control method for a dual-motor drive gearbox structure, the method further includes: switching between multiple working modes according to vehicle speed and load requirements, wherein in a single-motor drive mode, only one of the first drive motor 11 or the second drive motor 21 is turned on, while the other is in an idling or stopped state.

[0055] When executing the uninterrupted power shifting strategy, a torque smoothing transition step is also included: during the process of the second drive motor 21 restoring torque output, the torque of the second drive motor 21 is linearly increased, while the torque of the first drive motor 11 is linearly decreased, until the torque distribution between the two reaches the target ratio.

[0056] Working principle This application provides a dual-motor drive gearbox structure and its control method. The dual-motor drive gearbox structure of this application is provided with a first power mechanism 10, which includes a first drive motor 11, a first input shaft 12 connected to the output end of the first drive motor 11, two sets of gear pairs on the first input shaft 12, and a first shifting actuator 13 for selectively locking the two sets of gear pairs; and a second power mechanism 20, which includes a second drive motor 21, a second input shaft 22 connected to the output end of the second drive motor 21, two sets of gear pairs located on the second input shaft 22, and a second shifting actuator 23 for selectively locking the two sets of gear pairs. The auxiliary gearbox merging mechanism 30 includes a planetary gear mechanism consisting of a planetary carrier 32, a sun gear 31, and an internal gear ring 33, and a main gearbox output shaft 34 loosely fitted inside the sun gear 31. Two sets of gear pairs on the first input shaft 12 and two sets of gear pairs on the second input shaft 22 are respectively connected to the main gearbox output shaft 34 and the sun gear 31 for transmission. The auxiliary gearbox output mechanism 40 includes a rear auxiliary gearbox 41, in which a secondary gearbox output shaft 42 coaxially connected to the main gearbox output shaft 34 is provided. The secondary gearbox output shaft 42 is connected to the planetary carrier 32 for transmission, and the internal gear ring 33 is fixedly connected to the rear auxiliary gearbox 41.

[0057] Therefore, the dual-motor drive gearbox structure of this application is provided with a first power mechanism 10 and a second power mechanism 20 arranged in parallel. The auxiliary gearbox merging mechanism 30 is provided with a main gearbox output shaft 34 and a planetary gear mechanism that are drively connected to the first power mechanism 10 and the second power mechanism 20. The output ends of the main gearbox output shaft 34 and the planetary gear mechanism are fixedly connected to the auxiliary gearbox output shaft 42. The first drive motor 11 and the second drive motor 21 can drive the main gearbox output shaft 34 and the planetary gear mechanism to rotate separately or simultaneously. Compared with the single motor with a reduction gearbox arrangement, this application can achieve uninterrupted power shifting, greatly improving shifting comfort; and can match the torque output of the two motors in real time according to the wheel end torque required when the vehicle is driving, greatly improving economy.

[0058] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0059] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0060] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A dual-motor drive gearbox structure, characterized in that, include: The first power mechanism (10) includes a first drive motor (11), a first input shaft (12) connected to the output end of the first drive motor (11), two sets of gear pairs on the first input shaft (12), and a first shifting actuator (13) for selectively locking the two sets of gear pairs. The second power mechanism (20) includes a second drive motor (21), a second input shaft (22) connected to the output end of the second drive motor (21), two sets of gear pairs located on the second input shaft (22), and a second shifting actuator (23) for selectively locking the two sets of gear pairs. The auxiliary gearbox merging mechanism (30) includes a planetary gear mechanism consisting of a planet carrier (32), a sun gear (31) and an internal gear ring (33), and a main gearbox output shaft (34) loosely fitted inside the sun gear (31). The two sets of gear pairs on the first input shaft (12) and the two sets of gear pairs on the second input shaft (22) are respectively connected to the main gearbox output shaft (34) and the sun gear (31) for transmission. The auxiliary gearbox output mechanism (40) includes a rear auxiliary gearbox (41), in which a secondary gearbox output shaft (42) is provided, which is coaxially connected to the main gearbox output shaft (34). The secondary gearbox output shaft (42) is connected to the planetary carrier (32) for transmission, and the internal gear ring (33) is fixedly connected to the rear auxiliary gearbox (41).

2. The dual-motor drive gearbox structure as described in claim 1, characterized in that: The second power mechanism (20) further includes a high-low gear switching mechanism (50), which includes a third input shaft (51) connected to the output end of the second drive motor (21). The second input shaft (22) and the third input shaft (51) are coaxially arranged, and the third input shaft (51) is located between the second drive motor (21) and the second input shaft (22). An intermediate shaft (52) is arranged parallel to the second input shaft (22) and the third input shaft (51). A first gear pair is provided between the third input shaft (51) and the intermediate shaft (52), and a second gear pair is provided between the second input shaft (22) and the intermediate shaft (52). A third shifting actuator (53) for selectively locking the first gear pair and the second gear pair is provided on the second input shaft (22).

3. The dual-motor drive gearbox structure as described in claim 2, characterized in that: The output end of the intermediate shaft (52) is connected to a PTO power take-off (58). The first gear pair includes a first driving gear (54) and a first driven gear (55) meshing with each other. The first driving gear (54) is fixed on the third input shaft (51), and the first driven gear (55) is fixed on the intermediate shaft (52). The second gear pair includes a second driving gear (56) and a second driven gear (57) meshing with each other. The second driving gear (56) is fixed on the intermediate shaft (52), and the second driven gear (57) is loosely fitted on the second input shaft (22). The third shifting actuator (53) is used to selectively lock the first driving gear (54) and the second driven gear (57).

4. The dual-motor drive gearbox structure as described in claim 1, characterized in that: The two sets of gear pairs on the first input shaft (12) include a third driving gear (14) and a fourth driving gear (15) respectively loosely fitted on the first input shaft (12), a third driven gear (16) fixed on the main output shaft (34) and meshed with the third driving gear (14), and a fourth driven gear (17) fixed on the sun gear (31) and meshed with the fourth driving gear (15). The two sets of gear pairs on the second input shaft (22) include a fifth driving gear (24) and a sixth driving gear (25) respectively loosely fitted on the second input shaft (22). The fifth driving gear (24) meshes with the third driven gear (16), and the sixth driving gear (25) meshes with the fourth driven gear (17).

5. The dual-motor drive gearbox structure as described in claim 4, characterized in that: The main output shaft (34) is fitted with a hollow sun gear shaft (35) that connects to the sun gear (31). The fourth driven gear (17) is fixed on the hollow sun gear shaft (35). The fourth driven gear (17) and the hollow sun gear shaft (35) are fitted with a clearance fit through internal splines and external splines. The third driven gear (16) and the main output shaft (34) are fitted with a clearance fit through internal splines and external splines.

6. The dual-motor drive gearbox structure as described in claim 4, characterized in that: The number of teeth of the third driving gear (14) is different from the number of teeth of the fifth driving gear (24), so that the speed ratio of the third driving gear (14) to the third driven gear (16) is different from the speed ratio of the fifth driving gear (24) to the third driven gear (16). The number of teeth of the fourth driving gear (15) is the same as or different from the number of teeth of the sixth driving gear (25), so that the speed ratio of the fourth driving gear (15) to the fourth driven gear (17) is different from the speed ratio of the sixth driving gear (25) to the fourth driven gear (17).

7. The dual-motor drive gearbox structure as described in claim 4, characterized in that: The auxiliary gearbox output mechanism (40) also includes a disengagement mechanism (43) fixed on the auxiliary gearbox output shaft (42) for engaging or disengaging the planetary carrier (32). When the rotational speeds of the fourth drive gear (15) and the sixth drive gear (25) reach a set threshold, the disengagement mechanism (43) disengages from the planetary carrier (32).

8. A control method for a dual-motor driven gearbox structure, characterized in that, The method uses the dual-motor drive gearbox structure according to any one of claims 1 to 7, and the method includes: Obtain the vehicle's driving status parameters, which include at least vehicle speed and load requirements; The target gear and target operating mode are determined based on the driving status parameters. When a gear shift is detected as needed and the vehicle is in drive mode, a power-uninterrupted gear shift strategy is implemented: Control the first drive motor (11) to maintain the current gear and output drive torque; Control the second drive motor (21) to reduce the output torque to a preset threshold, and control the second shift actuator (23) to perform gear switching; After the second gear shifting actuator (23) completes the gear shifting, it controls the second drive motor (21) to resume torque output and controls the first drive motor (11) to perform gear shifting or maintain the current state; Throughout the gear shifting process, the auxiliary gearbox output shaft (42) always receives drive torque from at least one of the first drive motor (11) or the second drive motor (21).

9. The control method for a dual-motor drive gearbox structure as described in claim 8, characterized in that: The target operating modes include multiple modes such as single-motor drive mode, dual-motor drive mode, driving charging mode, and parking power generation mode. The method further includes switching between the multiple working modes according to the vehicle speed and load requirements, wherein in the single motor drive mode, only one of the first drive motor (11) or the second drive motor (21) is turned on, while the other is in an idle or stopped state.

10. The control method for a dual-motor drive gearbox structure as described in claim 8, characterized in that: When executing the power uninterrupted shifting strategy, a torque smoothing transition step is also included: during the process of the second drive motor (21) restoring torque output, the torque of the second drive motor (21) is linearly increased, while the torque of the first drive motor (11) is linearly decreased until the torque distribution between the two reaches the target ratio.

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