Dual-motor heavy truck electric drive axle and drive control method thereof

Abstract

A double-motor heavy truck electric drive axle comprises a main motor, a sun gear, a single-stage planet row connected with the main motor, a main reduction gear set connected with a planet carrier of the single-stage planet row and a differential mechanism meshed with the main reduction gear set and located below the main motor. The auxiliary motor is connected with the main reduction gear set and arranged opposite to the main motor, and the gear shifting and speed changing assembly has a two-gear speed changing function and is assembled between the single-stage planet row and the main reduction gear set and connected with the axle housing. A gear ring of the single-stage planet row is locked with the axle housing or the planet carrier along with gear shifting of the gear shifting and speed changing assembly. According to the invention, the efficient operation range of the motors is widened, the cost is reduced, the transmission efficiency and the flexibility of dual-motor driving are improved, power interruption during gear shifting is avoided, the passing performance of a vehicle under severe working conditions is improved, the axial size of the electric drive axle is reduced, and the arrangement of the electric drive axle is facilitated. The invention further provides a driving control method of the dual-motor heavy truck electric drive axle.

Description

Technical Field

[0001] The present invention relates to a dual-motor heavy-duty truck electric drive axle, belonging to the technical field of electric drive axles. The present invention also relates to a drive control method for a dual-motor heavy-duty truck electric drive axle. Background Art

[0002] At present, the technology of electric drive axle assemblies is increasingly widely used in the field of heavy commercial vehicles. The power assembly of an electric drive axle usually uses an electric motor to provide power, and after passing through a planetary gear train for speed reduction, the power is input into a differential gear train, and finally the power is output to the wheels through the differential gear train. In the actual use of new energy vehicles, the vehicle needs to adapt to a variety of complex working conditions, and it is necessary to meet the high torque requirements when fully loaded and climbing slopes, and also meet the high efficiency requirements when cruising at high speeds. For example, when driving on a highway, the vehicle needs to maintain a high speed to reach the destination quickly and safely; while when driving on a rough mountain road, the vehicle needs to have a stronger power output to overcome the complex and changeable road conditions; it is very difficult for a single-motor drive axle to meet the power output requirements under various working conditions. Dual motors have quite an advantage over single motors in terms of improving drive efficiency. Therefore, dual-motor electric drive axles are gradually being applied. Through the cooperation of dual motors, higher power output is provided to meet the power requirements under different working conditions. However, the existing dual-motor multi-speed electric drive axles still have the following problems: 1. The driving mode of dual motors is not flexible enough and there is a problem of huge power consumption. The requirements for the power of the motors are relatively high. Under heavy load conditions, the motors need to maintain high power output, with high energy consumption, a narrow high-efficiency power area, and low energy utilization rate, which affects the cruising range.

[0003] 2. When driving on muddy, soft dirt roads or in areas without roads, the wheels are prone to slipping and the passability is poor. There is a power interruption during gear shifting, which will affect the comfort of the vehicle. Moreover, the power interruption in scenarios such as mining areas with harsh working conditions and climbing long slopes will seriously affect driving safety.

[0004] 3. The differential and the two motors are respectively arranged on both sides of the paired gears and the single-stage planetary row, with a relatively large axial length and an insufficiently compact structure. Therefore, the volume is often large and it is not easy to install and arrange. Summary of the Invention

[0005] The dual-motor heavy-duty truck electric drive axle provided by the present invention broadens the high-efficiency operating range of the motors, reduces costs, improves transmission efficiency and the flexibility of dual-motor drive, avoids power interruption during gear shifting, improves the passing performance of the vehicle under harsh working conditions, reduces the axial dimension of the electric drive axle, and facilitates the arrangement of the electric drive axle. The present invention also provides a drive control method for a dual-motor heavy-duty truck electric drive axle.

[0006] To achieve the above object, the technical solution adopted by the present invention is: The electric drive axle of a dual-motor heavy-duty truck comprises a main motor, a single-stage planetary gearbox connected with a sun gear and the main motor, a main reduction gear set connected with a planet carrier of the single-stage planetary gearbox, and a differential meshing with the main reduction gear set and located below the main motor. The differential is characterized in that it also comprises an auxiliary motor connected with the main reduction gear set and arranged opposite to the main motor, and a shifting speed component with a two-speed shifting function. The shifting speed component is assembled between the single-stage planetary gearbox and the main reduction gear set and connected with the axle housing, and the ring gear of the single-stage planetary gearbox is locked with the axle housing or the planet carrier as the shifting speed component shifts gears.

[0007] Preferably, the main reduction gear set comprises an output gear coaxially fixed with the output shaft of the planet carrier and a main reduction gear meshed with the output gear, and the main reduction gear meshes with the differential housing of the differential.

[0008] Preferably, the output gear is coaxially connected to the output end of the auxiliary motor.

[0009] Preferably, the output shaft of the planetary carrier passes through the output gear and is connected to the output end of the auxiliary motor.

[0010] Preferably, the gear shifting assembly includes a synchronizer gear fixed coaxially with the ring gear, a synchronizer sleeve slidably assembled on the synchronizer gear along the axial direction, an L gear fixed to the bridge housing, and an H gear coaxially fixed with the output gear. The synchronizer sleeve moves to the left and combines with the L gear, and moves to the right and combines with the H gear.

[0011] Preferably, the outer end of the ring gear is meshed with the planetary gear of the single-stage planetary gear set, the inner end is supported on the output shaft of the planetary carrier through a bearing, and the synchronizer gear is fixed to the outer periphery of the inner end of the ring gear.

[0012] Preferably, the rated power of the auxiliary motor is smaller than the rated power of the main motor.

[0013] The driving control method of the dual-motor heavy-duty truck electric drive axle described above is characterized in that: the two gears of the speed shift assembly are set to the L gear and the H gear, and the speed shift assembly is in a neutral position between the L gear and the H gear in an initial state; Under light load conditions, the speed shifting assembly is shifted to the H gear to lock the ring gear and the planetary carrier, and the main motor is used for transmission to form a light load direct drive mode; Under heavy load conditions, the speed shift assembly is shifted to the L gear to lock the ring gear and the bridge housing, and the main motor is used for transmission to form a torque-increasing movement mode; Under adverse working conditions, shift the speed shift assembly to L gear to lock the ring gear and the bridge housing, and use the main motor and auxiliary motor to drive synchronously to form an auxiliary escape mode.

[0014] Preferably, "shifting the shift gear assembly to the H gear to lock the ring gear and the planet carrier" means moving the synchronizer sleeve to the right to engage with the H gear; "shifting the shift gear assembly to the L gear to lock the ring gear and the axle housing" means moving the synchronizer sleeve to the left to engage with the L gear.

[0015] The beneficial effects of the invention are: In the dual-motor heavy truck electric drive axle of the present invention, the main motor is connected to the sun gear of the single-stage planetary gear set, and the auxiliary motor is connected to the main reduction gear set. The main motor serves as the main transmission component, and the auxiliary motor serves as the auxiliary transmission component; when the ring gear is locked with the axle housing as the shift gear assembly shifts gears, the power of the main motor is decelerated and torque-increased by the single-stage planetary gear set, output from the planet carrier and transmitted to the main reduction gear set. The main reduction gear set drives the differential to operate, so as to drive the wheels. By utilizing the characteristics of a large speed ratio of the single-stage planetary gear set, low-speed high-torque drive is achieved, which is suitable for heavy-load working conditions. When driving on long uphill slopes or muddy sections and other harsh working conditions that require continuous output of high-torque power, while the main motor performs low-speed high-torque drive, the auxiliary motor is started to drive the main reduction gear set, forming synchronous drive of the main motor and the auxiliary motor. The auxiliary motor shares a part of the output power of the main motor, reducing the output power of the main motor, which not only improves the power sealing of the driving torque, but also enables both motors to operate in the high-efficiency range, so as to reduce energy consumption, extend the driving time of the main motor, and increase the cruising range; when the ring gear is locked with the planet carrier as the shift gear assembly shifts gears, the power of the main motor is transmitted to the single-stage planetary gear set. In the single-stage planetary gear set, only a small speed ratio reduction is formed between the sun gear and the planetary gears, and then the planet carrier and the ring gear are driven to rotate synchronously to transmit the power to the main reduction gear set to drive the wheels, which is suitable for light-load working conditions, achieving high-speed low-torque drive, increasing the driving speed, and enabling the motor to operate in the high-efficiency range, reducing energy consumption; by adjusting the speed ratio of the single-stage planetary gear set through shifting the shift gear assembly, rapid switching between high-speed low-torque gears and low-speed high-torque gears is realized, reducing the number of gears, simplifying the speed change control structure and process. By using the auxiliary motor to share the output power of the main motor, the high-efficiency operation range of the motor is broadened, the cost is reduced, the transmission efficiency and the flexibility of dual-motor drive are improved; in harsh working conditions, synchronous drive of the two motors is used, and the shifting of the shift gear assembly will not affect the normal drive of the auxiliary motor, avoiding power interruption during shifting and improving the passing performance of the vehicle under harsh working conditions; the main motor and the auxiliary motor are arranged oppositely, the shift gear assembly is arranged between the single-stage planetary gear set and the main reduction gear set, and the differential is arranged below the main motor. By utilizing the compact structure of the single-stage planetary gear set and the setting that the differential is axially staggered with the motor, the axial dimension of the electric drive axle is reduced, which is convenient for the layout of the electric drive axle. Description of the Drawings

[0016] Figure 1 It is a transmission schematic diagram of the dual-motor heavy truck electric drive axle of the present invention.

[0017] Figure 2 It is a transmission schematic diagram of the dual-motor heavy truck electric drive axle when forming L gear power.

[0018] Figure 3 Schematic diagram of the transmission of a dual-motor heavy truck electric drive axle when forming H-gear power. Specific implementation manner

[0019] The following is combined with Figures 1 to 3 to make a detailed description of the embodiments of the present invention.

[0020] The dual-motor heavy truck electric drive axle includes a main motor 1, a single-stage planetary gear set 2 connected to the main motor 1, a main reduction gear set 3 connected to the planet carrier 22 of the single-stage planetary gear set 2, and a differential 4 meshing with the main reduction gear set 3 and located below the main motor 1. It is characterized in that: it further includes an auxiliary motor 5 connected to the main reduction gear set 3 and disposed opposite to the main motor 1, and a shift transmission assembly 6 with two-speed shifting function. The shift transmission assembly 6 is assembled between the single-stage planetary gear set 2 and the main reduction gear set 3 and connected to the axle housing 7. The ring gear 23 of the single-stage planetary gear set 2 is locked with the axle housing 7 or the planet carrier 22 as the shift transmission assembly 6 shifts gears.

[0021] For the dual-motor heavy-duty truck electric drive axle described above, the main motor 1 is connected to the sun gear 21 of the single-stage planetary gear set 2, and the auxiliary motor 5 is connected to the main reduction gear set 3. The main motor 1 serves as the main transmission component, and the auxiliary motor 2 serves as the auxiliary transmission component. When the ring gear 23 is locked to the axle housing 7 with the shifting of the shifting and speed-changing component 6, the power of the main motor 1 is decelerated and torque-increased by the single-stage planetary gear set 2, output from the planet carrier 22 and transmitted to the main reduction gear set 3. The main reduction gear set 3 drives the differential 4 to operate so as to drive the wheels. By utilizing the characteristic of the large speed ratio of the single-stage planetary gear set, low-speed and high-torque drive is achieved, which is suitable for heavy-load working conditions. In harsh working conditions such as climbing long slopes or muddy sections where high-torque power needs to be continuously output, while the main motor performs low-speed and high-torque drive, the auxiliary motor 5 is started to transmit power to the main reduction gear set 3, forming synchronous transmission of the main motor 1 and the auxiliary motor 5. The auxiliary motor 5 shares a part of the output power of the main motor 1, reducing the output power of the main motor 1. This not only improves the power sealing of the driving torque, but also enables both motors to operate in the high-efficiency range, so as to reduce energy consumption, extend the transmission time of the main motor 1, and increase the cruising range. When the ring gear 23 is locked to the planet carrier 22 with the shifting of the shifting and speed-changing component 6, the power of the main motor 1 is transmitted to the single-stage planetary gear set. Only a small speed ratio reduction is formed between the sun gear 21 and the planet gears in the single-stage planetary gear set 2, and then the planet carrier 22 and the ring gear 23 are driven to rotate synchronously to transmit the power to the main reduction gear set 3 to drive the wheels, which is suitable for light-load working conditions, achieving high-speed and low-torque drive, increasing the driving speed, and enabling the motor to operate in the high-efficiency range, reducing energy consumption. By utilizing the shifting of the speed-changing and shifting component 6 to adjust the speed ratio of the single-stage planetary gear set 2, rapid switching between high-speed and low-torque gears and low-speed and high-torque gears is realized, the number of gears is reduced, and the speed-changing control structure and process are simplified. By using the auxiliary motor to share the output power of the main motor, the high-efficiency operation range of the motor is broadened, the cost is reduced, the transmission efficiency and the flexibility of dual-motor drive are improved. In harsh working conditions, synchronous transmission of the two motors is adopted, and the shifting of the shifting and speed-changing component will not affect the normal transmission of the auxiliary motor, avoiding power interruption during shifting and improving the passing performance of the vehicle in harsh working conditions. The main motor 1 and the auxiliary motor 5 are arranged oppositely, the shifting and speed-changing component 6 is arranged between the single-stage planetary gear set 2 and the main reduction gear set 3, and the differential 4 is arranged below the main motor 1. By utilizing the compact structure of the single-stage planetary gear set 2 and the setting that the differential and the motor are axially staggered, the axial dimension of the electric drive axle is reduced, facilitating the arrangement of the electric drive axle.

[0022] Among them, the main reduction gear set 3 includes an output gear 31 coaxially fixed to the output shaft of the planet carrier 22 and a main reduction gear 32 meshing with the output gear 31. The main reduction gear 32 meshes with the differential case of the differential 4. The planet carrier 22 drives the output gear 31 to rotate synchronously, the output gear 31 drives the main reduction gear 32 to rotate, and the main reduction gear 32 drives the differential case to rotate, causing the differential to move, and driving the wheels through the half shafts in the differential 4.

[0023] Among them, the output gear 31 is coaxially connected to the output end of the auxiliary motor 5. When the auxiliary motor 5 starts, it directly drives the output gear 31 to rotate. The power is transmitted to the differential through the speed reduction between the output gear 31 and the main reduction gear 32. The auxiliary motor 5 directly transmits power to the main reduction gear set 3, shares a part of the output power under harsh working conditions, reduces the output power of the main motor, enables both the main motor 1 and the auxiliary motor 5 to operate in the high-efficiency range, increases the torque density of the wheels, ensures that the vehicle can maintain a large torque output for a long time under harsh working conditions, and improves the transmission efficiency of the vehicle under harsh working conditions.

[0024] Among them, the output shaft of the planet carrier 22 passes through the output gear 31 and is connected to the output end of the auxiliary motor 5. The output gear 31 is fixed on the output shaft of the planet carrier 22, and the auxiliary motor 5 is connected to the output shaft of the planet carrier 22, so that the planet carrier 22, the output gear 31 and the auxiliary motor 5 are connected together through the output shaft of the planet carrier, simplifying the transmission structure and improving the transmission reliability.

[0025] Among them, the shift and speed change assembly 6 includes a synchronizer gear 61 coaxially fixed with the ring gear 23, a synchronizer sleeve 62 slidably assembled axially on the synchronizer gear 61, an L-gear 63 fixed to the axle housing 7, and an H-gear 64 coaxially fixed with the output gear 31. The synchronizer sleeve 62 moves to the left to engage with the L-gear 63 and moves to the right to engage with the H-gear 64. In the initial state, the synchronizer sleeve 62 is located between the L-gear 63 and the H-gear 64 and is not engaged with either of them. When the synchronizer sleeve 62 moves to the left to engage with the L-gear 63, the ring gear 23 is locked to the axle housing 7, and the single-stage planetary gear set 2 uses the planet carrier 22 as the output end to perform a large speed ratio reduction on the power of the main motor 1. The power is further reduced by the main reduction gear set 3 to form a low-speed and high-torque driving torque input to the differential, forming the L-gear power of the wheels; when the synchronizer sleeve 62 moves to the right to engage with the H-gear 64, the ring gear 23 and the planet carrier 22 are locked together, and a small speed ratio reduction between the sun gear 21 and the planet gear 24 is formed in the single-stage planetary gear set 2. Then, the planet gear 24 drives the planet carrier 22 and the internal gear ring 24 to rotate synchronously to transmit the power to the main reduction gear set 3. The power is further reduced by the main reduction gear set 3 to form a high-speed and low-torque driving torque input to the differential, forming the H-gear power of the wheels, realizing the rapid switching between the high-speed and low-torque gear and the low-speed and high-torque gear, reducing the number of gears, and simplifying the speed change control structure and process.

[0026] Among them, the outer end of the ring gear 23 is meshed with the planetary gear 24 of the single-stage planetary row 2, and the inner end is supported on the output shaft of the planetary carrier 22 through a bearing. The synchronizer gear 61 is fixed to the outer periphery of the inner end of the ring gear 23. The inner end of the ring gear 23 is supported on the output shaft of the planetary carrier 22, and the synchronizer gear 61 is fixed to the inner end of the ring gear 23, forming a single-stage planetary row 2, a speed shift assembly 6 and a main reduction gear set 3 coaxially connected in sequence, making the speed shift assembly 6 easier to assemble, reducing the axial size, and improving the compactness of the structure.

[0027] Among them, the rated power of the auxiliary motor 5 is less than the rated power of the main motor 1. As an auxiliary transmission component, the auxiliary motor 5 requires a smaller rated power, which can not only meet the needs of auxiliary transmission, but also make the main motor 1 and the auxiliary motor 5 work in a high-efficiency range during auxiliary transmission, reducing energy consumption, and a smaller motor can be selected as the auxiliary motor 5 to reduce space occupancy and cost.

[0028] The present invention also protects a driving control method for a dual-motor heavy-duty truck electric drive axle, characterized in that: the two gears of the speed shift assembly 6 are set to the L gear and the H gear, and the speed shift assembly 6 is in a neutral position between the L gear and the H gear in an initial state; Under light load conditions, the speed shifting assembly 6 is shifted to the H gear to lock the ring gear 23 and the planetary carrier 22, and the main motor 1 is used for transmission to form a light load direct drive mode; Under heavy load conditions, the speed shift assembly 6 is shifted to the L gear to lock the ring gear 23 and the bridge housing 7, and the main motor 1 is used for transmission to form a torque-increasing movement mode; Under adverse working conditions, the speed shift assembly 6 is shifted to the L gear to lock the ring gear 23 and the bridge housing 7, and the main motor 1 and the auxiliary motor 5 are driven synchronously to form an auxiliary escape mode.

[0029] The driving control method of the dual-motor heavy-duty truck electric drive axle described above. Under heavy-load conditions, the ring gear 23 is locked with the axle housing 7. The power of the main motor 1 is decelerated and torque-increased by the single-stage planetary gear set 2, output from the planet carrier 22 and transmitted to the main reduction gear set 3. The main reduction gear set 3 drives the differential 4 to operate to form the power of the L gear to drive the wheels. By utilizing the characteristic of the large speed ratio of the single-stage planetary gear set, low-speed high-torque driving is achieved. When driving on a long uphill or muddy road section and other harsh conditions that require continuous output of high-torque power, while the main motor is performing low-speed high-torque driving, the auxiliary motor 5 is started to transmit power to the main reduction gear set 3, forming the synchronous transmission of the main motor 1 and the auxiliary motor 5. The auxiliary motor 5 shares a part of the output power of the main motor 1, reducing the output power of the main motor 1, which not only improves the power sealing of the driving wheel torque, but also enables both motors to operate in the high-efficiency range, so as to reduce energy consumption, extend the transmission time of the main motor 1, and increase the cruising range; Under light-load conditions, when the ring gear 23 is locked with the planet carrier 22, the power of the main motor 1 is transmitted to the single-stage planetary gear set. In the single-stage planetary gear set 2, only a small speed ratio reduction is formed between the sun gear 21 and the planet gears, and then the planet carrier 22 and the ring gear 23 are driven to rotate synchronously to transmit the power to the main reduction gear set 3. The main reduction gear set 3 drives the differential 4 to operate to form the power of the H gear to drive the wheels, achieving high-speed low-torque driving, increasing the driving speed, and enabling the motor to operate in the high-efficiency range, reducing energy consumption; The speed ratio of the single-stage planetary gear set 2 is adjusted by shifting the shift gear assembly 6 to achieve a quick switch between the high-speed low-torque gear and the low-speed high-torque gear. The auxiliary motor shares the output power of the main motor to broaden the high-efficiency operation range of the motor, reduce costs, improve the transmission efficiency and the flexibility of dual-motor drive; In harsh conditions, the two motors are synchronously transmitted, and the shifting of the shift gear assembly will not affect the normal transmission of the auxiliary motor, avoiding power interruption during shifting, and improving the passing performance of the vehicle under harsh conditions.

[0030] Among them, "shifting the speed shifting component 6 to the H gear to lock the ring gear 23 and the planet carrier 22" means that the synchronizer sleeve 62 moves to the right to engage with the H-gear 64; "shifting the speed shifting component 6 to the L gear to lock the ring gear 23 and the axle housing 7" means that the synchronizer sleeve 62 moves to the left to engage with the L-gear 63. In the initial state, the synchronizer sleeve 62 is located between the L-gear 63 and the H-gear 64. When the synchronizer sleeve 62 moves to the left to engage with the L-gear 63, the ring gear 23 is locked to the axle housing 7. The single-stage planetary gear set 2 uses the planet carrier 22 as the output end to perform a large speed ratio reduction on the power of the main motor. After the power is further reduced by the main reduction gear set 3, a low-speed and high-torque driving torque is input to the differential to form the L-gear power of the wheel; when the synchronizer sleeve 62 moves to the right to engage with the H-gear 64, the ring gear 23 and the planet carrier 22 are locked together. A small speed ratio reduction between the sun gear 21 and the planet gear 24 is formed in the single-stage planetary gear set 2, and then the planet gear 24 drives the planet carrier 22 and the internal gear ring 24 to rotate synchronously to transmit the power to the main reduction gear set 3. After the power is further reduced by the main reduction gear set 3, a high-speed and low-torque driving torque is input to the differential to form the H-gear power of the wheel, realizing the rapid switching between the high-speed and low-torque gear and the low-speed and high-torque gear.

[0031] The technical solutions of the embodiments of the present invention have been completely described above in conjunction with the accompanying drawings. It should be noted that the described embodiments are only a part of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the protection scope of the present invention.

Claims

1. A dual-motor heavy-duty truck electric drive axle, comprising a main motor, a single-stage planetary gearbox connected to the main motor by a sun gear, a main reduction gear set connected to a planetary carrier of the single-stage planetary gear set, and a differential meshing with the main reduction gear set and located below the main motor, characterized in that: It also includes an auxiliary motor connected to the main reduction gear set and arranged opposite to the main motor, and a gear shifting assembly with a two-speed shifting function. The gear shifting assembly is assembled between the single-stage planetary gear set and the main reduction gear set and connected to the bridge housing. The ring gear of the single-stage planetary gear set is locked with the bridge housing or the planetary carrier as the gear shifting assembly shifts gears.

2. The dual-motor heavy-duty truck electric drive axle according to claim 1 is characterized in that: The main reduction gear set comprises an output gear coaxially fixed with the output shaft of the planet carrier and a main reduction gear meshed with the output gear, and the main reduction gear meshes with the differential housing of the differential.

3. The dual-motor heavy-duty truck electric drive axle according to claim 2 is characterized in that: The output gear is coaxially connected to the output end of the auxiliary motor.

4. The dual-motor heavy-duty truck electric drive axle according to claim 3 is characterized by: The output shaft of the planetary carrier passes through the output gear and is connected to the output end of the auxiliary motor.

5. The dual-motor heavy-duty truck electric drive axle according to claim 3 is characterized by: The gear shifting assembly includes a synchronizer gear fixed coaxially with the ring gear, a synchronizer sleeve slidably assembled on the synchronizer gear along the axial direction, an L gear fixed to the bridge housing, and an H gear fixed coaxially with the output gear. The synchronizer sleeve moves to the left and combines with the L gear, and moves to the right and combines with the H gear.

6. The dual-motor heavy-duty truck electric drive axle according to claim 5 is characterized by: The outer end of the gear ring is meshed with the planetary gear of the single-stage planetary row, the inner end is supported on the output shaft of the planetary carrier through a bearing, and the synchronizer gear is fixed on the outer periphery of the inner end of the gear ring.

7. The dual-motor heavy-duty truck electric drive axle according to claim 6, characterized in that: The rated power of the auxiliary motor is smaller than the rated power of the main motor.

8. The driving control method of the electric drive axle of a dual-motor heavy truck according to any one of claims 1 to 7, characterized in that: The two gears of the speed shift assembly are set to L gear and H gear, and the speed shift assembly is in a neutral position between L gear and H gear in an initial state; Under light load conditions, the speed shifting assembly is shifted to the H gear to lock the ring gear and the planetary carrier, and the main motor is used for transmission to form a light load direct drive mode; Under heavy load conditions, the speed shift assembly is shifted to the L gear to lock the ring gear and the bridge housing, and the main motor is used for transmission to form a torque-increasing movement mode; Under adverse working conditions, shift the speed shift assembly to L gear to lock the ring gear and the bridge housing, and use the main motor and auxiliary motor to drive synchronously to form an auxiliary escape mode.

9. The driving control method of the electric drive axle of a dual-motor heavy truck according to claim 8 is characterized by: "Shifting the speed shift assembly to H gear so that the ring gear and the planetary carrier are locked" means moving the synchronizer sleeve to the right to engage with the H gear; "shifting the speed shift assembly to L gear so that the ring gear and the bridge housing are locked" means moving the synchronizer sleeve to the left to engage with the L gear.

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