Heavy dumper electric drive axle and driving method thereof

Abstract

An electric drive axle of a heavy dumper comprises a motor, first-stage planet rows, a speed change assembly with a two-gear speed change function, a differential mechanism, a half shaft assembled on the differential mechanism and a wheel end planet row assembled at the end of the half shaft, and is characterized in that the two first-stage planet rows are symmetrically arranged on the two sides of the half shaft and meshed with a differential shell of the differential mechanism respectively; the four speed change assemblies are symmetrically arranged on the two sides of the half shaft, the input ends of the speed change assemblies are connected with the motors in a one-to-one correspondence mode, and the output ends of the speed change assemblies are meshed with the first-stage planet row located on the same side of the half shaft. The transmission path is shortened, the wheel end torque is improved, and the high torque density during heavy load and the high motor efficiency during light load are guaranteed; the axial space of the axle axis is fully utilized to optimize the transmission structure, the mass of the two sides of the half shaft is balanced, the structural arrangement balance is improved, and the stability of the electric drive axle in the running state is improved. The invention further provides a driving method of the electric drive axle of the heavy dumper.

Description

Technical Field

[0001] The present invention relates to an electric drive axle of a heavy-duty dump truck and a driving method thereof, and belongs to the technical field of pure electric variable speed drive. Background Art

[0002] Heavy-duty dump trucks face complex operating conditions such as extreme loads, frequent starts and stops, and braking on long slopes, placing stringent demands on their powertrains. These systems must handle exceptionally high torque while ensuring high reliability and efficient energy return. Purely electric heavy-duty commercial trucks typically utilize either a central electric drive or an electric axle to deliver power. Compared to a central electric drive, an electric axle offers greater space savings and a higher level of integration, leading to its widespread application.

[0003] The transmission efficiency and structural design of electric drive axles used in medium- and heavy-duty trucks directly impact vehicle performance. Existing electric drive axle configurations include parallel-axis, coaxial, and planetary gear types. Existing parallel-axis electric drive axles suffer from lengthy transmission chains, high energy loss, and high maintenance costs. Furthermore, their unbalanced powertrain layout leads to poor load-carrying capacity and significant safety risks. Coaxial electric drive axles offer shorter transmission chains, but are typically limited to two motors, failing to meet load standards. They also suffer from insufficient torque density and poor operating adaptability, posing challenges in climbing heavy-load grades, adapting to complex road conditions, and improving energy efficiency. Planetary gear electric drive axles utilize a multi-stage planetary gearbox and multiple clutches or brakes to create variable speed ratios for gear shifting, effectively increasing wheel-end torque and offering a compact design. However, this approach carries relatively high structural and control costs. This proposal improves the electric drive axle in several areas, including the power transmission path and distribution method, the structure, and the control strategy, to meet the drive requirements of heavy-duty dump trucks. Summary of the Invention

[0004] The electric drive axle for heavy-duty dump trucks provided by this invention shortens the transmission path, increases wheel-end torque, and ensures high torque density under heavy loads and high motor efficiency under light loads. It also fully utilizes the axial space of the axle axis to optimize the transmission structure, balance the mass on both sides of the axle shaft, improve the structural layout balance, and enhance the stability of the electric drive axle during operation. The invention also provides a driving method for the electric drive axle of a heavy-duty dump truck.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is: The electric drive axle of a heavy-duty dump truck includes a motor, a first-stage planetary gear, a transmission assembly with a two-speed shifting function, a differential, a half-shaft assembled on the differential, and a wheel-end planetary gear assembled on the end of the half-shaft. It is characterized by: there are two groups of first-stage planetary gears, which are symmetrically arranged on both sides of the half-shaft and respectively meshed with the differential case of the differential; there are four groups of transmission assemblies, which are symmetrically arranged on both sides of the half-shaft; the input end of the transmission assembly is connected to the motor in a one-to-one correspondence, and the output end meshes with the first-stage planetary gear located on the same side of the half-shaft.

[0006] Preferably, the two groups of speed change assemblies located on the same side of the half shaft are distributed in mirror symmetry, the ring gear of the first-stage planetary gear is fixed to the bridge housing, the planet carrier is engaged with the differential housing, and the sun gear is connected to the output end of the speed change assembly.

[0007] Preferably, the speed change assembly includes an input shaft connected to the motor, a constant meshing shaft meshing with the input shaft, an intermediate shaft parallel to the constant meshing shaft, and a shift gear sleeve mounted on the intermediate shaft that can slide in the axial direction. The intermediate shaft is connected to the input shaft or the constant meshing shaft as the shift gear sleeve slides, and the intermediate shaft meshes with the input end of the sun gear.

[0008] Preferably, the input shaft is coaxially aligned with the intermediate shaft, a direct-connected gear is coaxially fixed on the input shaft, the direct-connected gear is located in front of the shift sleeve, the shift sleeve slides forward and combines with the direct-connected gear, connecting the intermediate shaft and the input shaft to form a second-gear transmission of the speed change assembly.

[0009] Preferably, a rotatable intermediate gear is mounted on the intermediate shaft, the intermediate gear is engaged with the constant mesh shaft, the intermediate gear is located at the rear side of the shift sleeve, the shift sleeve slides backward and engages with the intermediate gear, connecting the intermediate shaft with the constant mesh shaft to form a first gear transmission of the speed change assembly.

[0010] Preferably, there are multiple constant meshing shafts evenly distributed around the periphery of the input shaft, the intermediate shaft is coaxially fixed with the input driving gear, and the input end of the sun gear is integrally formed with an input driven gear meshing with the input driving gear.

[0011] Preferably, two input driven gears are provided on the input end of the sun gear, and each input driven gear is respectively engaged with an input driving gear of a set of speed change components.

[0012] Preferably, the output gear and the hydraulic retarder driving gear are fixed to both ends of the differential housing respectively, the output gear is engaged with the output end of the planetary carrier, and the hydraulic retarder driving gear is engaged with the hydraulic retarder assembled in the axle housing.

[0013] In the above-mentioned driving method of the electric drive axle of the heavy-duty dump truck, when the vehicle is lightly loaded, only one or two motors are used for driving, and when two motors are used for driving, the speed change assemblies corresponding to the two motors are located on the same side of the half-shaft; When the vehicle is heavily loaded, three or four motors are used to drive it; When multiple motors are involved in driving, the speed change components corresponding to each motor are shifted in sequence to achieve speed change.

[0014] Preferably, when the vehicle is lightly loaded and on a flat road, only one motor is used to drive the vehicle, and when the vehicle is lightly loaded and on an uphill or muddy road, two motors are used to drive the vehicle; When the vehicle is heavily loaded, three motors are used to drive it on flat roads; when the vehicle is heavily loaded, four motors are used to drive it on uphill or muddy roads.

[0015] The beneficial effects of the present invention are: The electric drive axle of the heavy-duty dump truck of the present invention has a motor connected to the input end of the speed change assembly, two groups of primary planetary gears are symmetrically arranged on both sides of the half-shafts and respectively meshed with the differential housing, four groups of speed change assemblies are symmetrically arranged on both sides of the half-shafts, and the output end of the speed change assembly meshes with the primary planetary gears located on the same side of the half-shafts, forming a sequential transmission from the motor, speed change assembly, primary planetary gears, differential, half-shafts to the wheel-end planetary gears, and the speed change assembly transmits the power of the motor to the primary planetary gears. The advantages of the compact structure and large speed ratio of the primary planetary gears are utilized to improve the torque transmitted to the differential, that is, shorten the transmission path and increase the wheel-end torque, which can be adjusted according to the vehicle load and working conditions. The number of motors involved in the drive is reduced. One or two motors are used for driving when the vehicle is lightly loaded, and three or four motors are used for driving when the vehicle is heavily loaded. When speed change is required, multiple sets of speed change components are shifted in sequence to avoid power interruption and reduce gear shift shock, realize dynamic drive according to working conditions, and ensure high torque density under heavy load and high motor efficiency under light load; mesh the speed change component with the first-stage planetary gear located on the same side of the half-shaft to form a symmetrical transmission structure on both sides of the half-shaft, make full use of the axial space of the axle axis to optimize the transmission structure, balance the mass on both sides of the half-shaft, improve the balance of the structural layout, and improve the stability of the electric drive axle in the operating state. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the transmission structure of the electric drive axle of a heavy-duty dump truck in a specific implementation manner. DETAILED DESCRIPTION

[0017] The following combination Figure 1 The embodiments of the present invention are described in detail.

[0018] The electric drive axle of a heavy-duty dump truck includes a motor 1, a first-stage planetary gear 2, a transmission assembly 3 with a two-speed shifting function, a differential 4, a half-shaft 5 assembled on the differential 4, and a wheel-end planetary gear 6 assembled at the end of the half-shaft 5. It is characterized in that: there are two groups of first-stage planetary gears 2, which are symmetrically arranged on both sides of the half-shaft 5 and respectively meshed with the differential housing 41 of the differential 4; there are four groups of transmission assemblies 3, which are symmetrically arranged on both sides of the half-shaft 5; the input end of the transmission assembly 3 is connected to the motor 1 in a one-to-one correspondence, and the output end is meshed with the first-stage planetary gear 2 located on the same side of the half-shaft.

[0019] In the heavy-duty dump truck electric drive axle described above, the motor 1 is connected to the input end of the speed change assembly 3, two sets of primary planetary gears 2 are symmetrically arranged on both sides of the half shaft 5 and are respectively engaged with the differential housing 41, and four sets of speed change assemblies 3 are symmetrically arranged on both sides of the half shaft 5. The output end of the speed change assembly 3 is engaged with the primary planetary gear 2 located on the same side of the half shaft 5, forming a sequential transmission from the motor 1, the speed change assembly 3, the primary planetary gear 2, the differential 4, the half shaft 5 to the wheel end planetary gear 6. The speed change assembly 3 transmits the power of the motor to the primary planetary gear 2. The advantages of the compact structure and large speed ratio of the primary planetary gear 2 are used to increase the torque transmitted to the differential 4, that is, shorten the transmission path and increase the wheel end torque. The load and working conditions are adjusted to adjust the number of motors involved in the drive. When the vehicle is lightly loaded, one or two motors are used to drive the vehicle. When the vehicle is heavily loaded, three or four motors are used to drive the vehicle. When speed change is required, multiple groups of speed change components 3 are shifted in sequence to avoid power interruption and reduce gear shift shock, so as to achieve dynamic drive according to the working conditions and ensure high torque density under heavy load and high motor efficiency under light load. The speed change component 3 is meshed with the first-stage planetary gear 2 located on the same side of the half-shaft to form two groups of symmetrical transmission structures on both sides of the half-shaft 5, making full use of the axial space of the axle axis to optimize the transmission structure, balance the mass on both sides of the half-shaft, improve the balance of the structural layout, and improve the stability of the electric drive bridge in the operating state.

[0020] The two transmission assemblies 3 on the same side of the axle 5 are arranged in mirror-symmetrical arrangement. The ring gear 21 of the primary planetary gear set 2 is fixed to the axle housing, the planet carrier 22 meshes with the differential housing 41, and the sun gear 23 is connected to the output end of the transmission assembly 3. As can be seen from the accompanying drawings, two transmission assemblies 3 are provided on either side of the axle 5. The two transmission assemblies 3 on the same side of the axle are arranged in mirror-symmetrical arrangement and are respectively connected to the sun gear 23 of the primary planetary gear set 2 on the same side of the axle. The two transmission assemblies 3 on the same side of the axle are arranged along the axle axis, fully utilizing the space along the axle axis and optimizing the transmission structure. The two transmission assemblies 3 on the same side of the axle transmit power to the primary planetary gear set 2 on the same side of the axle, which drives the differential 4. When motors are driving both sides of the axle, the power of the two primary planetary gear sets converges at the differential housing 41.

[0021] Among them, the speed change assembly 3 includes an input shaft 31 connected to the motor 1, a constant meshing shaft 32 meshing with the input shaft 31, an intermediate shaft 33 parallel to the constant meshing shaft 32, and a shift gear sleeve 34 that can slide in the axial direction is mounted on the intermediate shaft 33. The intermediate shaft 33 is connected to the input shaft 31 or the constant meshing shaft 32 as the shift gear sleeve 33 slides, and the intermediate shaft 33 meshes with the input end of the sun gear 23. The motor 1 drives the input shaft 31 to rotate, and the input shaft 31 drives the constant mesh shaft 32 to rotate. When the shift gear sleeve 33 slides to connect the intermediate shaft 33 with the constant mesh shaft 32, the input shaft 31 drives the intermediate shaft 33 to rotate through the constant mesh shaft 32, and the intermediate shaft 33 transmits power to the sun gear 23, forming a first gear transmission of the speed change assembly. When the shift gear sleeve 33 slides to connect the intermediate shaft 33 with the input shaft 31, the input shaft 31 directly drives the intermediate shaft 33 to rotate, and the intermediate shaft 33 transmits power to the sun gear 23, forming a second gear transmission of the speed change assembly 3. In first gear transmission, the input shaft 31 forms an indirect transmission with the intermediate shaft 33 through the constant mesh shaft 32, and the power torque transmitted to the intermediate shaft 33 is greater and the speed is lower. In second gear power, the input shaft 31 and the intermediate shaft 33 form a direct transmission, and the power torque transmitted to the intermediate shaft 33 is less than that of the first gear transmission, and the speed is higher than that of the first gear transmission.

[0022] The input shaft 31 is coaxially aligned with the intermediate shaft 33. A direct-connection gear 35 is coaxially fixed to the input shaft 31. The direct-connection gear 35 is located in front of the shift sleeve 34. The shift sleeve 34 slides forward to engage with the direct-connection gear 35, connecting the intermediate shaft 33 to the input shaft 31 and forming the second gear of the transmission assembly. The combination of the shift sleeve 34 and the straight-side gear 34 is equivalent to directly connecting the intermediate shaft 33 to the input shaft 31. The input shaft 31 directly drives the rotation of the intermediate shaft 33. At this time, the speed of the intermediate shaft 33 is higher and the torque is lower, forming the second gear of the transmission assembly.

[0023] The intermediate shaft 33 is rotatably mounted with an intermediate gear 36, which meshes with the constant mesh shaft 32. Intermediate gear 36 is located behind the shift sleeve 34. The shift sleeve 34 slides rearward to engage with the intermediate gear 36, connecting the intermediate shaft 33 with the constant mesh shaft 32, thus establishing first gear transmission for the transmission assembly 3. When the shift sleeve 34 engages the intermediate gear 36, the input shaft 31 is indirectly connected to the intermediate shaft 33 via the constant mesh shaft 32. The input shaft 31 drives the constant mesh shaft 32 to rotate, which in turn drives the intermediate shaft 33 to rotate. At this point, the speed of the intermediate shaft 33 is lower, but the torque is higher, thus establishing first gear transmission for the transmission assembly. When the shift sleeve 34 is in the neutral position and is not engaged with the direct-connected gear 35 or the intermediate gear 36, the input shaft 31 is disconnected from the intermediate shaft 33, the power of the input shaft 21 cannot be transmitted to the intermediate shaft 33, and the speed change assembly 3 cannot transmit. Only when the shift sleeve 34 is engaged with the direct-connected gear 25 or the intermediate gear 36 can the power of the input shaft 31 be transmitted to the intermediate shaft 33, and the transmission of the speed change assembly 3 can be formed.

[0024] The constant mesh shafts 32 are multiple and evenly distributed around the periphery of the input shaft 31. An input driving gear 37 is coaxially fixed to the intermediate shaft 33. An input driven gear 24 is integrally formed on the input end of the sun gear 23 and meshes with the input driving gear 37. The multiple constant mesh shafts 32 collectively carry and transmit power, reducing inter-tooth stress, lowering wear during transmission, and improving the transmission reliability of the transmission assembly 3.

[0025] Two input driven gears 24 are provided at the input end of the sun gear 23. Each input driven gear 34 meshes with an input driving gear 37 of a transmission assembly 3. A primary planetary gear set 2 and two transmission assemblies 3 are provided on either side of the axle 5. The input driving gears 37 of the two transmission assemblies 3 on the same side of the axle mesh with the two input driven gears 34 on the input end of the sun gear on that side. This combines the power of the two transmission assemblies 3 at the input end of the sun gear 23, shortening the transmission path, optimizing the transmission structure, and improving transmission efficiency.

[0026] The differential housing 41 is secured to its two ends with an output gear 42 and a hydraulic retarder drive gear 43. The output gear 42 meshes with the output end of the planetary carrier 22, while the hydraulic retarder drive gear 43 meshes with the hydraulic retarder 7 mounted in the axle housing. The meshing of the output end of the planetary carrier 22 and the output gear 42 transmits power from the primary planetary gear set 2 to the differential housing 41, causing the differential 4 to rotate, driving the axle shafts 5. The hydraulic retarder 7 provides a buffering function, reducing the rotational speed of the differential housing 41 when descending long slopes, thereby reducing vehicle speed and ensuring driving safety.

[0027] In the above-mentioned driving method of the electric drive axle of the heavy-duty dump truck, when the vehicle is lightly loaded, only one or two motors 1 are used for driving, and when two motors 1 are used for driving, the speed change assemblies 3 corresponding to the two motors are located on the same side of the half shaft 5; When the vehicle is heavily loaded, three or four motors 1 are used to drive it; When multiple motors 1 participate in driving, the speed change assembly 3 corresponding to each motor 1 is shifted in sequence to achieve speed change.

[0028] The driving method described above uses one or two motors to drive the vehicle when it is lightly loaded. When two motors are used, the speed change assemblies 3 corresponding to the two motors are located on the same side of the axle 5. The two speed change assemblies 3 located on the same side of the axle transmit the power of the two motors 1 to the first-stage planetary gear 2 on the same side. Only the two motors located on one side of the axle are used for driving, and the two motors located on the other side of the axle do not participate in the driving. This shortens the transmission path, improves transmission efficiency, places the motors in a high-efficiency range, reduces energy consumption, ensures high efficiency of the motors under light load, and reduces energy consumption. When the vehicle is heavily loaded, three or four motors are used to drive the vehicle, meeting the high torque requirements of the wheel ends, improving power density, and meeting the continuous high torque driving requirements of heavy loads. When multiple motors 1 are used for driving, multiple speed change assemblies 3 shift gears in sequence to avoid power interruption and impact during the shifting process. This allows the distribution and number of motors involved in the drive to be adjusted according to the vehicle load and road conditions, and forms a speed shift through the speed change assemblies 3, thereby realizing a control strategy for dynamic driving according to the working conditions.

[0029] When the vehicle is lightly loaded, only one motor 1 is used for driving on flat roads. When the vehicle is lightly loaded, two motors 2 are used for driving on uphill or muddy roads. When the vehicle is heavily loaded, three motors 1 are used to drive the vehicle on a flat road; when the vehicle is heavily loaded, four motors 1 are used to drive the vehicle on an uphill or muddy road.

[0030] When the load is light, a maximum of two motors are used to drive the vehicle, ensuring that the motors are in the high-efficiency range and reducing energy consumption. When the load is heavy, at least three motors are used to drive the vehicle, increasing the wheel-end torque density and ensuring continuous high-power output. This ensures that the vehicle can escape from trouble in time under heavy load conditions, improves the heavy-duty dump truck's adaptability to working conditions, ensures reliable driving under multiple working conditions, and reduces energy consumption.

[0031] The above fully describes the technical solutions of the embodiments of the present invention in conjunction with the accompanying drawings. It should be noted that the embodiments described are only part of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

Claims

1. A heavy-duty dump truck electric drive axle includes a motor, a primary planetary gear, a transmission assembly with a two-speed shift function, a differential, a half-shaft assembled on the differential, and a wheel-end planetary gear assembled on the end of the half-shaft, characterized by: There are two sets of first-stage planetary gears, which are symmetrically arranged on both sides of the half-shafts and meshed with the differential case of the differential respectively. There are four sets of speed change assemblies, which are symmetrically arranged on both sides of the half-shafts. The input end of the speed change assembly is connected to the motor one-to-one, and the output end is meshed with the first-stage planetary gear on the same side of the half-shaft.

2. The heavy-duty dump truck electric drive axle according to claim 1, characterized in that: The two sets of speed change components located on the same side of the half-shaft are distributed in mirror symmetry. The ring gear of the first-stage planetary gear is fixed to the bridge housing, the planet carrier is meshed with the differential housing, and the sun gear is connected to the output end of the speed change component.

3. The heavy-duty dump truck electric drive axle according to claim 2, characterized in that: The speed change assembly includes an input shaft connected to the motor, a constant meshing shaft meshing with the input shaft, an intermediate shaft parallel to the constant meshing shaft, and a shift sleeve mounted on the intermediate shaft that can slide in the axial direction. The intermediate shaft is connected to the input shaft or the constant meshing shaft as the shift sleeve slides, and the intermediate shaft meshes with the input end of the sun gear.

4. The heavy-duty dump truck electric drive axle according to claim 3, characterized in that: The input shaft is coaxially aligned with the intermediate shaft, and a direct-connected gear is coaxially fixed on the input shaft. The direct-connected gear is located in front of the shift sleeve. The shift sleeve slides forward and engages with the direct-connected gear, connecting the intermediate shaft and the input shaft to form a second-gear transmission of the speed change assembly.

5. The heavy-duty dump truck electric drive axle according to claim 4, characterized in that: The intermediate shaft is equipped with a rotatable intermediate gear, which meshes with the constant mesh shaft. The intermediate gear is located at the rear side of the shift sleeve. The shift sleeve slides backward and engages with the intermediate gear, connecting the intermediate shaft with the constant mesh shaft to form a first gear transmission of the speed change assembly.

6. The heavy-duty dump truck electric drive axle according to claim 3, characterized in that: There are multiple constantly meshing shafts, which are evenly distributed around the periphery of the input shaft. The intermediate shaft is coaxially fixed with the input driving gear, and the input end of the sun gear is integrally formed with an input driven gear meshing with the input driving gear.

7. The heavy-duty dump truck electric drive axle according to claim 6, characterized in that: Two input driven gears are provided on the input end of the sun gear, and each input driven gear is respectively engaged with an input driving gear of a set of speed change components.

8. The heavy-duty dump truck electric drive axle according to claim 2, characterized in that: The output gear and the hydraulic retarder driving gear are fixed on both ends of the differential housing respectively. The output gear is engaged with the output end of the planetary frame, and the hydraulic retarder driving gear is engaged with the hydraulic retarder assembled in the axle housing.

9. The driving method of the electric drive axle of a heavy-duty dump truck according to any one of claims 1 to 8, wherein when the vehicle is lightly loaded, only one or two motors are used to drive the vehicle, and when two motors are used to drive the vehicle, the speed change assemblies corresponding to the two motors are located on the same side of the half-axle; When the vehicle is heavily loaded, three or four motors are used to drive it; When multiple motors are involved in driving, the speed change components corresponding to each motor are shifted in sequence to achieve speed change.

10. The driving method of the electric drive axle of a heavy-duty dump truck according to claim 9, characterized in that: When the vehicle is lightly loaded, only one motor is used to drive the vehicle on flat roads. When the vehicle is lightly loaded, two motors are used to drive the vehicle on uphill or muddy roads. When the vehicle is heavily loaded, three motors are used to drive it on flat roads; when the vehicle is heavily loaded, four motors are used to drive it on uphill or muddy roads.

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