Dual-motor planetary gear train speed change system and speed change control method thereof

Abstract

According to the dual-motor planetary gear train speed change system, the multi-gear speed change design that dual-motor coupling is combined with the planetary gear train is adopted, the efficient operation interval of the motors is increased, the driving requirements under different working conditions are met, energy consumption is reduced, an independent reverse gear is formed, the reliability of the system structure under the extreme working condition is improved, and the working condition adaptability of the speed change system is improved; the coupling assembly and the planetary gear train with the three planetary rows form a composite transmission structure, the system space layout is optimized, the structural compactness of the speed change system is improved, the axial size is shortened, the system weight is reduced, a brake and a clutch are arranged in the planetary gear train, multi-gear switching is formed, multi-gear expansibility and compact layout are both considered, and the transmission efficiency is improved. And the gear shifting impact is eliminated, and the driving experience is improved. The invention further provides a variable speed control method of the dual-motor planetary gear train variable speed system.

Description

Technical Field

[0001] The present invention relates to a dual-motor planetary gear train speed change system and a speed change control method thereof, belonging to the technical field of pure electric transmissions. Background Art

[0002] As electric vehicles continue to demand high-efficiency, multi-scenario power output, single-motor electric drive axles have significant limitations due to the high cost of a single high-power motor and its low efficiency under low-load conditions. This often leads to high vehicle energy consumption and unsatisfactory power performance. With the continuous advancement of technology, electric drive axles with dual-motor architectures have gradually become a popular application. By combining two relatively low-power motors, they not only reduce system costs but also, through precise speed ratio configuration, enable the motors to operate more frequently in the high-efficiency operating range, significantly improving vehicle economy and driving experience.

[0003] However, existing dual-motor, multi-speed electric drive systems rely on motor reversal for reverse gear, a design with significant drawbacks. Oil seals are susceptible to failure due to reverse oil pressure leakage during high-speed motor reversal. Furthermore, conventional unidirectional rotary oil pumps are unable to supply oil during reversal, creating a lubrication blind spot and insufficient lubrication of transmission components, impacting lifespan and safety. Furthermore, while planetary gearboxes can achieve speed ratio switching via brakes, existing technologies often rely on a single mechanical structure (such as parallel shafts or planetary gearboxes), making it difficult to balance multi-speed scalability with a compact layout. Summary of the Invention

[0004] The dual-motor planetary gear transmission system provided by this invention combines dual motor coupling with a planetary gear system's multi-speed transmission design, increasing the motor's efficient operating range to meet driving requirements under various operating conditions. The system also provides an independent reverse gear position, improving system reliability under extreme operating conditions and the transmission's adaptability to various operating conditions. This system combines multi-speed scalability with a compact layout, eliminates shift shock, and enhances the driving experience. The invention also provides a speed control method for the dual-motor planetary gear transmission system.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is: A dual-motor planetary gear transmission system includes a coupling assembly for coupling the power of two motors and a planetary gear train connected to the output end of the coupling assembly. The system is characterized in that the planetary gear train includes a first planetary row, a second planetary row, and a third planetary row connected in sequence from front to back, the second planetary row is equipped with a first brake, the third planetary row is equipped with a second brake, the output end of the first planetary row and the output end of the third planetary row are connected by a clutch, and the planetary gear train outputs forward gear power when the second brake or clutch is activated, or outputs reverse gear power when the first brake is activated.

[0006] Preferably, the coupling assembly includes two motors, an input shaft connected to the shaft ends of the motors, and a constant meshing shaft respectively meshed with the two input shafts, and the constant meshing shaft is connected to the input end of the planetary gear train.

[0007] Preferably, the front end of the constant meshing shaft is equipped with a lubrication pump for pumping lubricating fluid throughout the system.

[0008] Preferably, the first planetary row includes a first sun gear connected to the constant meshing shaft, a first planetary gear meshed with the first sun gear, a first planetary carrier assembled on the first planetary gear, and a first ring gear whose inner ring is meshed with the first planetary gear. The second planetary row includes a second sun gear, a second planetary gear meshed with the second sun gear, a second planetary carrier assembled on the second planetary gear, and a second ring gear whose inner ring is meshed with the second planetary gear. The third planetary row includes a third sun gear, a third planetary gear meshed with the third sun gear, a third planetary carrier assembled on the third planetary gear, and a third ring gear whose inner ring is meshed with the third planetary gear. The first row of ring gears is fixed, the first planetary carrier, the second sun gear and the third sun gear are fixedly connected, the second ring gear is fixedly connected to the third planetary carrier, an output shaft is assembled on the third planetary carrier, and the first planetary carrier is connected to the output shaft through a clutch.

[0009] Preferably, the first brake is mounted on the second planetary carrier, and the second brake is mounted on the third ring gear.

[0010] Preferably, an intermediate shaft is coaxially fixed on the first planetary carrier, the second sun gear and the third sun gear are fixed on the intermediate shaft, and a clutch is installed between the intermediate shaft and the output shaft, and the intermediate shaft and the output shaft are connected by engagement of the clutch.

[0011] The above-mentioned speed control method for the dual-motor planetary gear train speed change system is characterized by: The first brake and clutch are closed, the second brake is activated, and the planetary gear train outputs first gear forward power; The first and second brakes are closed, the clutch is activated, and the planetary gear train outputs forward second gear power; The second brake and clutch are closed, the first brake is activated, and the planetary gear train outputs reverse power.

[0012] Preferably, When the planetary gear outputs first gear power, the coupling assembly drives the first sun gear to rotate, and the power of the first sun gear is transmitted to the third planetary carrier and the output shaft through the first planetary carrier and the third sun gear; When the planetary gear outputs the second gear power, the coupling assembly drives the first sun gear to rotate, and the power of the first sun gear is transmitted to the output shaft through the first planetary carrier; When the planetary gear outputs reverse power, the coupling assembly drives the first sun gear to rotate, and the power of the first sun gear is transmitted to the third planetary gear and the output shaft through the first planetary carrier, the second sun gear, and the second ring gear.

[0013] The beneficial effects of the present invention are: The dual-motor planetary gear transmission system of the present invention couples the power of the two motors and transmits it to the planetary gear system. The planetary gear system has three sets of planetary gears. Brakes are installed on the second and third planetary gears. The clutch connects the output shaft of the first planetary gear and the output end of the third planetary gear. The planetary gear system outputs forward gear power when the second brake or the clutch is activated, or outputs reverse gear power when the first brake is activated. The dual-motor coupling is combined with the multi-speed transmission design of the planetary gear system to increase the efficient operation range of the motor, meet the driving requirements under different working conditions, reduce energy consumption, and avoid dependence on Reverse gear is achieved by reversing the motor to avoid the risk of oil seal failure in the system due to reverse gear formed by motor reversal, forming an independent reverse gear position, improving the reliability of the system structure under extreme working conditions, and improving the working adaptability of the speed change system. The coupling component and the planetary gear system with three sets of star rows form a composite transmission architecture, optimize the system spatial layout, improve the structural compactness of the speed change system, shorten the axial dimension and reduce the system weight, and set the brake and clutch in the planetary gear system to form multi-speed switching, which not only takes into account the multi-speed scalability and compact layout, but also eliminates the gear shift shock and improves the driving experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 Schematic diagram of the transmission structure of the dual-motor planetary gear transmission system in a specific implementation manner.

[0015] Figure 2 Schematic diagram of the transmission structure of the dual-motor planetary gear transmission system when outputting first gear forward power.

[0016] Figure 3 Schematic diagram of the transmission structure of the dual-motor planetary gear transmission system when outputting forward second gear power.

[0017] Figure 4 Schematic diagram of the transmission structure of the dual-motor planetary gear transmission system when outputting reverse power. DETAILED DESCRIPTION

[0018] The following combination Figures 1 to 4 The embodiments of the present invention are described in detail.

[0019] A dual-motor planetary gear transmission system includes a coupling assembly 1 for coupling the power of two motors, and a planetary gear train connected to the output end of the coupling assembly 1. The planetary gear train includes a first planetary row 2, a second planetary row 3, and a third planetary row 4 connected in sequence from front to back, the second planetary row 3 is equipped with a first brake 5, and the third planetary row 4 is equipped with a second brake 6. The output end of the first planetary row 2 and the output end of the third planetary row 4 are connected by a clutch 7. The planetary gear train outputs forward gear power when the second brake 6 or the clutch 7 is activated, and outputs reverse gear power when the first brake is activated.

[0020] In the dual-motor planetary gear transmission system described above, the coupling component 1 couples the power of the two motors and transmits it to the planetary gear system. The planetary gear system has three sets of planetary gears. The second planetary gear 3 and the third planetary gear 4 are equipped with brakes. The clutch 7 connects the output shaft of the first planetary gear 2 with the output end of the third planetary gear 4. The planetary gear system outputs forward gear power when the second brake 6 or the clutch 7 is activated, or outputs reverse gear power when the first brake 5 is activated. The dual-motor coupling combined with the multi-speed transmission design of the planetary gear system increases the motor's efficient operating range, meets the driving requirements under different working conditions, and reduces energy consumption. , avoid relying on motor reversal to achieve reverse gear, so as to avoid the risk of system oil seal failure caused by reverse gear formed by motor reversal, form an independent reverse gear, improve the reliability of the system structure under extreme working conditions, and improve the working condition adaptability of the speed change system. The coupling component 1 and the planetary gear system with three sets of star rows form a composite transmission architecture, optimize the system space layout, improve the structural compactness of the speed change system, shorten the axial dimension and reduce the system weight, and set the brake and clutch in the planetary gear system to form multi-speed switching, which takes into account the multi-speed scalability and compact layout, eliminates the gear shifting shock, and improves the driving experience.

[0021] The coupling assembly 1 includes two motors 11, an input shaft 12 connected to the shaft ends of the motors 11, and a constant mesh shaft 13 that meshes with the two input shafts 12, respectively. The constant mesh shaft 13 is connected to the input end of the planetary gear train. The input shaft 13 meshes with the constant mesh shaft 13, coupling the power of the two motors 11 to the constant mesh shaft 13, which transmits the power to the planetary gear train. The coupling assembly 1 has a parallel axis structure. The constant mesh shaft 13 rotates when the motors are activated, transmitting the power to the planetary gear train. The planetary gear train cannot output power if the first brake, second brake, and clutch are not activated. It can only output power when the first brake, second brake, or clutch are activated.

[0022] The front end of the constant mesh shaft 13 is equipped with a lubrication pump 14 that pumps lubricant throughout the system. After the motor starts, the constant mesh shaft 13 rotates, driving the lubrication pump 14 to pump oil to lubricate the gears and bearings throughout the system. The constant mesh shaft 13 is unaffected by gear shifting and can drive the lubrication pump 14 in forward, reverse, and neutral gears, ensuring a continuous and stable supply of lubricant under all operating conditions. This solves the lubrication blind spot problem caused by oil pump failure during reverse in traditional electric drive systems. The independent reverse gear control protects the sealing effect of the system's oil seal, while the lubrication pump's directional and continuous oil supply protects the system's lubrication capacity, providing dual protection for the transmission system and significantly improving its structural reliability and stability under extreme operating conditions.

[0023] Among them, the first planetary row 2 includes a first sun gear 21 connected to the constant meshing shaft, a first planetary gear meshed with the first sun gear 21, a first planetary carrier 22 mounted on the first planetary gear, and a first ring gear 23 whose inner ring is meshed with the first planetary gear. The second planetary row 3 includes a second sun gear 31, a second planetary gear meshed with the second sun gear 31, a second planetary carrier 32 mounted on the second planetary gear, and a second ring gear 33 whose inner ring is meshed with the second planetary gear. The third planetary row 4 includes a third sun gear 41, a third planetary gear meshed with the third sun gear 41, a third planetary carrier 42 mounted on the third planetary gear, and a third ring gear 43 whose inner ring is meshed with the third planetary gear. The first row ring gear 23 is fixed, the first planetary carrier 22, the second sun gear 31 and the third sun gear 41 are fixedly connected, the second ring gear 33 is fixedly connected to the third planetary carrier 42, the output shaft 44 is mounted on the third planetary carrier 42, and the first planetary carrier 22 and the output shaft 44 are connected via a clutch 7. The first ring gear 23 is fixed, so that the first planetary gear 2 can only output power from the first planetary carrier 22. When the clutch is activated, the first planetary carrier 22 is connected to the output shaft 44, and the power of the first planetary carrier 22 is directly transmitted to the output shaft. At this time, the second planetary gear 3 and the third planetary gear 4 do not participate in the transmission. Only when the clutch is closed and the first brake or the second brake is activated can the second planetary gear 3 and the third planetary gear 4 participate in the transmission. During driving, only one of the clutch, the first brake, or the second brake needs to be activated, which simplifies the shift control and avoids shift shock.

[0024] The first brake 5 is mounted on the second planetary carrier 32, and the second brake 6 is mounted on the third ring gear 43. When the first brake and the clutch are both inactive and only the second brake 6 is activated, the power of the coupling assembly 1 is constantly engaged with the shaft 13 and transmitted to the first sun gear 21. The power of the first sun gear 21 is transmitted to the first planetary carrier 22. The first planetary carrier 22 drives the third sun gear 43 to move. The third sun gear 41 transmits the power to the third planetary carrier 42, which is then outputted by the output shaft 44, forming the first forward gear power of the transmission system, meeting the high-torque drive requirements under heavy-load conditions. When the first brake 5 and the second brake 6 are both closed and only the clutch is activated, the power of the coupling assembly 1 is constantly engaged with the shaft 13 and transmitted to the first sun gear 21. The power of the first sun gear 21 is transmitted to the first planetary carrier 22. The first planetary carrier 22 directly drives the output shaft 44 to move. The second forward gear power of the transmission system is formed. The torque of the second forward gear power is less than that of the first forward gear power, while the speed is greater than that of the first forward gear power. The second forward gear power meets the low-torque and high-speed driving requirements under light load conditions; when the second brake and the clutch are both closed and only the first brake is working, the power of the coupling assembly 1 is often transmitted to the first sun gear 21 by the meshing shaft 13, and the power of the first sun gear 21 is transmitted to the first planetary carrier 22, and the first planetary carrier 22 transmits the power to the second sun gear 31. Since the second planetary carrier 32 is fixed by the first brake 5, the second sun gear 31 will drive the second ring gear 33 to rotate in the reverse direction, and the third planetary carrier 42 rotates in the reverse direction coaxially with the second ring gear 33, causing the output shaft 44 to rotate in the reverse direction, forming the reverse gear power of the transmission system.

[0025] The intermediate shaft 24 is coaxially fixed to the first planetary carrier 22, and the second and third sun gears 31 and 41 are fixed to the intermediate shaft 24. The clutch 7 is installed between the intermediate shaft 24 and the output shaft 44, and the intermediate shaft 24 and the output shaft 44 are connected by the engagement of the clutch 7. The intermediate shaft 24 can be integrally formed with the first planetary carrier 22. The second and third sun gears 31 and 41 are assembled on the intermediate shaft 24 and rotate synchronously with the rotation of the first planetary carrier 22. When the clutch 7 is activated, the intermediate shaft 24 and the output shaft 44 are connected. When the clutch 7 is deactivated, the connection between the intermediate shaft 24 and the output shaft 44 is disconnected.

[0026] The above-mentioned speed control method for the dual-motor planetary gear train speed change system is characterized by: The first brake 5 and clutch 7 are closed, the second brake 6 is activated, and the planetary gear train outputs the first gear forward power; The first brake 5 and the second brake 6 are closed, the clutch 7 is activated, and the planetary gear train outputs forward second gear power; The second brake 6 and the clutch 7 are closed, the first brake 5 is activated, and the planetary gear train outputs reverse power.

[0027] In the above-described speed control method, the planetary gear system outputs the first forward gear power when the second brake 6 is activated, outputs the second forward gear power when the clutch 7 is activated, or outputs the reverse gear power when the first brake 5 is activated. The first forward gear power meets the high-torque drive requirement under heavy-load conditions; the torque of the second forward gear power is less than that of the first forward gear power, while the speed is greater than that of the first forward gear power. The second forward gear power meets the low-torque and high-speed drive requirement under light-load conditions; the dual-motor coupling combined with the multi-speed speed change design of the planetary gear system increases the motor's efficient operating range, meets the drive requirements under different working conditions, reduces energy consumption, avoids relying on motor reversal to achieve reverse gear, and avoids the risk of system oil seal failure caused by motor reversal to form reverse gear, forms an independent reverse gear, improves the reliability of the system structure under extreme working conditions, and improves the working condition adaptability of the speed change system.

[0028] in, When the planetary gear outputs first gear power, the coupling assembly 1 drives the first sun gear 21 to rotate, and the power of the first sun gear 21 is transmitted to the third planetary carrier 42 and the output shaft 44 through the first planetary carrier 22 and the third sun gear 41; When the planetary gear outputs the second gear power, the coupling assembly 1 drives the first sun gear 21 to rotate, and the power of the first sun gear 21 is transmitted to the output shaft 44 through the first planetary carrier 22; When the planetary gear outputs reverse power, the coupling assembly 1 drives the first sun gear 21 to rotate, and the power of the first sun gear 21 is transmitted to the third planetary carrier 42 and the output shaft 44 through the first planetary carrier 22, the second sun gear 31 and the second ring gear 33.

[0029] When the first brake and the clutch are both not activated and only the second brake 6 is activated, the power of the coupling assembly 1 is often engaged with the shaft 13 and transmitted to the first sun gear 21, the power of the first sun gear 21 is transmitted to the first planetary carrier 22, the first planetary carrier 22 drives the third sun gear 43 to move, the third sun gear 43 transmits the power to the third planetary carrier 42, and the power is output by the output shaft 44, forming the forward first gear power of the transmission system; when the first brake and the second brake are both closed and only the clutch is activated, the power of the coupling assembly 1 is often engaged with the shaft 13 and transmitted to the first sun gear 21, the power of the first sun gear 21 is transmitted to the first planetary carrier 22, the third sun gear 43 transmits the power to the third planetary carrier 42, and the third sun gear 43 transmits the power to the third planetary carrier 42, and the third sun gear 43 is output by the output shaft 44, forming the forward first gear power of the transmission system; when the first brake and the second brake are both closed and only the clutch is activated, the power of the coupling assembly 1 is often engaged with the shaft 13 and transmitted to the first sun gear 21, the power of the first sun gear 21 is transmitted to the first planetary carrier 22, the third sun gear 43 transmits the power to the third planetary carrier A planet carrier 22 directly drives the output shaft 44 to move, forming the second forward gear power of the transmission system; when the second brake and the clutch are both closed and only the first brake is working, the power of the coupling assembly 1 is often transmitted to the first sun gear 21 by the meshing shaft 13, and the power of the first sun gear 21 is transmitted to the first planet carrier 22. The first planet carrier 22 transmits the power to the second sun gear 31. Since the second planet carrier 32 is fixed by the first brake 5, the second sun gear 31 will drive the second ring gear 33 to rotate in the reverse direction, and the third planet carrier 42 will rotate in the reverse direction coaxially with the second ring gear 33, causing the output shaft 44 to rotate in the reverse direction, forming the reverse gear power of the transmission system.

[0030] 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 dual-motor planetary gear train speed change system, comprising a coupling assembly for coupling the power of two motors, and a planetary gear train connected to the output end of the coupling assembly, characterized in that: The planetary gear train includes a first planetary gear, a second planetary gear, and a third planetary gear connected in sequence from front to back. The second planetary gear is equipped with a first brake, and the third planetary gear is equipped with a second brake. The output end of the first planetary gear and the output end of the third planetary gear are connected by a clutch. The planetary gear train outputs forward gear power when the second brake or the clutch is activated, or outputs reverse gear power when the first brake is activated.

2. The dual-motor planetary gear transmission system according to claim 1, characterized in that: The coupling assembly includes two motors, an input shaft connected to the shaft ends of the motors, and a constant meshing shaft respectively meshed with the two input shafts, wherein the constant meshing shaft is connected to the input end of the planetary gear system.

3. The dual-motor planetary gear transmission system according to claim 2, characterized in that: The front end of the constant meshing shaft is equipped with a lubrication pump that pumps lubricating fluid to the entire system.

4. The dual-motor planetary gear transmission system according to claim 2, characterized in that: The first planetary row includes a first sun gear connected to the constant meshing shaft, a first planetary gear meshed with the first sun gear, a first planetary carrier mounted on the first planetary gear, and a first ring gear whose inner ring is meshed with the first planetary gear. The second planetary row includes a second sun gear, a second planetary gear meshed with the second sun gear, a second planetary carrier mounted on the second planetary gear, and a second ring gear whose inner ring is meshed with the second planetary gear. The third planetary row includes a third sun gear, a third planetary gear meshed with the third sun gear, a third planetary carrier mounted on the third planetary gear, and a third ring gear whose inner ring is meshed with the third planetary gear. The first row ring gear is fixed, the first planetary carrier, the second sun gear and the third sun gear are fixedly connected, the second ring gear is fixedly connected to the third planetary carrier, an output shaft is mounted on the third planetary carrier, and the first planetary carrier is connected to the output shaft through a clutch.

5. The dual-motor planetary gear transmission system according to claim 4, characterized in that: The first brake is mounted on the second planetary carrier, and the second brake is mounted on the third ring gear.

6. The dual-motor planetary gear transmission system according to claim 4, characterized in that: The intermediate shaft is coaxially fixed on the first planet carrier, the second sun gear and the third sun gear are fixed on the intermediate shaft, the clutch is installed between the intermediate shaft and the output shaft, and the intermediate shaft and the output shaft are connected through the engagement of the clutch.

7. The speed control method of a dual-motor planetary gear transmission system according to any one of claims 1 to 6, characterized in that: The first brake and clutch are closed, the second brake is activated, and the planetary gear train outputs first gear forward power; The first and second brakes are closed, the clutch is activated, and the planetary gear train outputs forward second gear power; The second brake and clutch are closed, the first brake is activated, and the planetary gear train outputs reverse power.

8. The speed control method of the dual-motor planetary gear train speed change system according to claim 6, characterized in that: When the planetary gear outputs first gear power, the coupling assembly drives the first sun gear to rotate, and the power of the first sun gear is transmitted to the third planetary carrier and the output shaft through the first planetary carrier and the third sun gear; When the planetary gear outputs the second gear power, the coupling assembly drives the first sun gear to rotate, and the power of the first sun gear is transmitted to the output shaft through the first planetary carrier; When the planetary gear outputs reverse power, the coupling assembly drives the first sun gear to rotate, and the power of the first sun gear is transmitted to the third planetary gear and the output shaft through the first planetary carrier, the second sun gear, and the second ring gear.

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