Heavy truck electric drive assembly and gear shifting control method thereof

Abstract

According to the heavy truck electric drive assembly, the power coupling assembly transmits coupling power of the multiple motors to the planetary gear train, the three planet rows in the planetary gear train are sequentially connected, and the clutch set and the brake are both installed in the planetary gear train to reduce the axial size of the drive assembly; speed ratio switching of the planetary gear train can be formed by controlling the clutch set and the brake, six forward gear power and six reverse gear power are formed on the output shaft, the driving requirements of the heavy truck under various working conditions are met, the efficient operation interval coverage rate of the motor is increased, energy consumption is reduced, and the requirement for the power of a single motor is reduced. Multi-gear expansion and compact layout of the driving assembly are achieved, gear shifting efficiency is improved, gear shifting impact is reduced, the running stability of the heavy truck is improved, reverse gear is prevented from being achieved by relying on motor reverse rotation, the risks of oil seal sealing failure and lubricating blind areas caused by motor reverse rotation are avoided, and the passing performance of the heavy truck under severe working conditions is improved. The invention further provides a gear shifting control method of the electric drive assembly.

Description

Technical Field

[0001] The present invention relates to a heavy-duty truck electric drive assembly, belonging to the technical field of pure electric variable speed drive. Background Art

[0002] Pure electric heavy-duty trucks' multi-speed motor drive systems utilize electricity as their power source, are air-friendly, and effectively reduce vehicle exhaust emissions, making them a hot topic for research and development and application. Medium and heavy-duty trucks require both high torque in the constant torque range and high speeds in the constant power range to meet requirements for acceleration and hill climbing. Therefore, medium and heavy-duty trucks, which require relatively high torque while also emphasizing economy, generally utilize a motor-and-transmission electric drive system to meet the vehicle's speed range and torque requirements.

[0003] The existing heavy-duty truck electric drive transmission system has the following shortcomings: 1. Multi-speed electric drive systems require high motor power, high speed, gears that cover various operating conditions, and miniaturization. However, existing system gears cannot achieve comprehensive coverage of operating conditions, and the increase in motor power is contrary to the lightweight and miniaturized design. Therefore, it is difficult to balance multi-speed scalability and compact layout. At the same time, there are also problems such as long power interruption time and large impact during gear shifting.

[0004] 2. In multi-speed electric drive systems, the design of reverse gear, which relies on motor reversal, presents a significant flaw. During high-speed motor reversal, the oil seal is susceptible to failure due to reverse oil pressure leakage. Furthermore, conventional unidirectional rotary oil pumps are unable to supply oil under reverse conditions, creating a lubrication blind spot and insufficient lubrication of transmission components, impacting lifespan and safety.

[0005] 3. The motor and gearbox are controlled synchronously. In muddy and steep slopes, the torque distribution accuracy cannot be accurately distributed according to the wheel-end torque requirements, affecting the vehicle's passing performance. Summary of the Invention

[0006] The heavy-duty truck electric drive assembly provided by this invention meets the diverse driving requirements of heavy-duty trucks, reduces energy consumption, enables multi-gear expansion and a compact layout for the drive assembly, mitigates the risks of oil seal failure and lubrication blind spots caused by motor reverse rotation, improves the structural reliability of the drive assembly under extreme operating conditions, and enhances the truck's maneuverability under harsh conditions. The invention also provides a shift control method for the heavy-duty truck electric drive assembly.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is: The heavy-duty truck electric drive assembly includes a power coupling assembly, a planetary gear train and an output shaft that are sequentially connected in a transmission manner. The power coupling assembly couples the power of multiple motors and is characterized in that it also includes a clutch group and a brake. The planetary gear train includes planetary gear row 1, planetary gear row 2 and planetary gear row 3 that are coaxially connected in sequence. The output shaft is connected to planet carrier 3 of planetary gear row 3. The power coupling assembly is connected to sun gear 1 of planetary gear row 1. The clutch is assembled on sun gear 1 of planetary gear row 1. Sun gear 1 is connected to sun gear 2 and / or planet carrier 2 of planetary gear row 2 through the clutch group. Planet carrier 1 of planetary gear row 1 and ring gear 2 of planetary gear row 2 are fixed. Planet carrier 2 of planetary gear row 2 and ring gear 3 of planetary gear row 3 are fixed. Sun gear 2 of planetary gear row 2 and sun gear 3 of planetary gear row 3 are fixed. Brake C, brake D and brake E are respectively installed on ring gear 1 of planetary gear row 1, ring gear 2 of planetary gear row 2 and ring gear 3 of planetary gear row 3. The power gear switching of the output shaft is controlled by the clutch group and the three brakes.

[0008] Preferably, the power coupling assembly includes at least two motors, an input shaft connected to the motor, and a constant meshing shaft parallel to and meshing with the input shaft, wherein the constant meshing shaft is coaxially connected to the sun gear.

[0009] Preferably, the constant meshing shaft and the sun gear 1 are coaxially connected through spline fitting.

[0010] Preferably, the clutch group includes a clutch A that cooperates with sun gear 2 and a clutch B that cooperates with planet carrier 2. Clutch A and clutch B are both installed on sun gear 1. Sun gear 1 is combined with sun gear 2 when clutch A is started, and sun gear 1 is combined with planet carrier 2 when clutch B is started.

[0011] Preferably, the sun gear 2 and the sun gear 3 are fixed on the intermediate shaft respectively, and the sun gear 1 is coupled to the intermediate shaft when the clutch A is started.

[0012] Preferably, the sun gear 1 is in the shape of a gear sleeve, clutch A and clutch B are respectively installed in sun gear 1, the front end of planet carrier 2 extends into sun gear 1 and is radially aligned with clutch B, and the front end of the intermediate shaft passes through planet carrier 2 and extends into sun gear 1 and is radially aligned with clutch A.

[0013] Preferably, it further includes a hydraulic damper engaged with the output shaft.

[0014] The above-mentioned shift control method of the electric drive assembly is characterized by: When the clutch group connects sun gear 1 to sun gear 2, brake E is activated to fix ring gear 3, and forward first gear power is generated on the output shaft; When the clutch group connects sun gear 1 to sun gear 2, brake D is activated to fix ring gear 2, and forward second gear power is generated on the output shaft; When the clutch group connects sun gear 1 to sun gear 2, brake C is activated to fix ring gear 1, and forward third gear power is generated on the output shaft; When the clutch group connects sun gear 1 with sun gear 2 and planet carrier 2 respectively, the fourth gear forward power is formed on the output shaft; When the clutch group connects sun gear 1 to planet carrier 2, brake C is activated to fix ring gear 1, and forward fifth gear power is generated on the output shaft; When the clutch group connects sun gear 1 to planet carrier 2, brake D is activated to fix ring gear 2, and forward sixth gear power is generated on the output shaft; When brake C is activated to fix ring gear 1, brake E is activated to fix ring gear 3, and reverse gear power is generated on the output shaft.

[0015] Preferably, “when the clutch group connects sun gear 1 to sun gear 2” means starting clutch A to connect sun gear 1 to the intermediate shaft; “When the clutch group connects the sun gear 1 to the planet carrier 2” means starting the clutch B to connect the sun gear 1 to the planet carrier 2; “When the clutch group connects sun gear 1 to sun gear 2 and planet carrier 2 respectively” means: clutch A and clutch B are started synchronously to connect sun gear 1 to the intermediate shaft and planet carrier 2 respectively.

[0016] The beneficial effects of the present invention are: The heavy-duty truck electric drive assembly of the present invention has a power coupling component that transmits the coupled power of multiple motors to the planetary gear system. The three planetary gear sets in the planetary gear system are connected in sequence. Sun gear 2 and sun gear 3 are fixedly connected. Planet carrier 1 and ring gear 2 are fixedly connected. Planet carrier 2 and ring gear 3 are fixedly connected. The clutch is assembled on sun gear 1 to disconnect or connect sun gear 1 with sun gear 2 and planet carrier 2. The brakes are respectively installed on the ring gears of the three planetary gear sets to perform braking control on the three ring gears respectively. By controlling the clutch group and the brake, the speed ratio switching of the planetary gear system can be formed, and six forward gears and one reverse gear power can be formed on the output shaft, which can meet the driving needs of various working conditions such as heavy-load escape, heavy-load acceleration, heavy-load high-speed driving, light-load escape, light-load overtaking, light-load high-speed cruising and reverse transmission of heavy trucks, improve the coverage of the motor's efficient operation range, reduce energy consumption, and reduce the power requirements of a single motor. The clutch group and the brake are both installed in the planetary gear system to reduce the axial size of the drive assembly. The characteristics of the planetary gear system, such as large speed ratio, speed ratio switching with the brake, compact structure and easy integration of the multi-stage planetary gear system, are used to realize multi-gear expansion and compact layout of the drive assembly. The speed ratio of the planetary gear system is switched by opening and closing the clutch group and the brake, forming speed shifting, improving shifting efficiency, reducing shifting shock, and improving the operating stability of heavy trucks.

[0017] By utilizing the transmission characteristic that the positioning of the planet carrier in the planetary gear set will form a relative reverse rotation between the sun gear and the ring gear, the power output is transformed from the forward rotation input of the motor to the reverse rotation, thereby realizing reverse gear transmission. The power for both forward and reverse gears is generated by the forward rotation of the motor, avoiding reliance on the reverse rotation of the motor to achieve reverse gear, and avoiding the risk of oil seal failure and lubrication blind spots caused by motor reversal. An independent reverse gear is formed, thereby improving the structural reliability of the drive assembly under extreme working conditions.

[0018] A split-shaft arrangement of the power coupling component and the planetary gear train is formed to support separate control of the power coupling component and the planetary gear train. The number of starting motors can be adjusted according to road conditions during driving, forming an accurate match between power output and driving needs. This not only reduces energy consumption, but also improves the torque distribution accuracy of the wheel ends on both sides of the heavy truck in escape scenarios such as mud and steep slopes, thereby improving the passing performance of the heavy truck under adverse working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the transmission structure of the heavy-duty truck electric drive assembly in a specific implementation method.

[0020] Figure 2 Schematic diagram of the transmission structure of the heavy-duty truck electric drive assembly when outputting first-gear forward power.

[0021] Figure 3 Schematic diagram of the transmission structure of the heavy-duty truck electric drive assembly when outputting forward second gear power.

[0022] Figure 4 Schematic diagram of the transmission structure of the heavy-duty truck electric drive assembly when outputting third-gear forward power.

[0023] Figure 5 Schematic diagram of the transmission structure of the heavy-duty truck electric drive assembly when outputting four forward gears.

[0024] Figure 6 Schematic diagram of the transmission structure of the heavy-duty truck electric drive assembly when outputting five forward gears.

[0025] Figure 7 Schematic diagram of the transmission structure of the heavy-duty truck electric drive assembly when outputting six forward gears.

[0026] Figure 8 Schematic diagram of the transmission structure of the heavy-duty truck electric drive assembly when outputting reverse gear power. DETAILED DESCRIPTION

[0027] The following combination Figures 1 to 8 The embodiments of the present invention are described in detail.

[0028] The heavy truck electric drive assembly includes a power coupling component 1, a planetary gear system 4 and an output shaft 2 that are sequentially connected in a transmission manner. The power coupling component 1 couples the power of multiple motors and is characterized by: further including a clutch group 3 and a brake, the planetary gear system includes a planetary gear 5, a planetary gear 6 and a planetary gear 7 that are sequentially coaxially connected, the output shaft 2 is connected to the planet carrier 3 72 of the planetary gear 7, the power coupling component 1 is connected to the sun gear 51 of the planetary gear 5, the clutch group 3 is installed on the sun gear 51 of the planetary gear 5, and the sun gear 51 is connected to the planetary gear 7 through the clutch group 3. The sun gear 2 61 and / or planet carrier 2 6 of planetary gear 2 are connected, the planet carrier 1 52 of planetary gear 1 5 and the ring gear 2 63 of planetary gear 2 6 are fixed, the planet carrier 2 62 of planetary gear 2 6 and the ring gear 3 73 of planetary gear 3 7 are fixed, the sun gear 2 61 of planetary gear 2 6 and the sun gear 3 71 of planetary gear 3 7 are fixed, and brakes C, D and E are respectively installed on the ring gear 1 53 of planetary gear 1 5, the ring gear 2 63 of planetary gear 2 6 and the ring gear 3 73 of planetary gear 3 7, and the power gear switching of the output shaft is controlled by the clutch group 3 and the three brakes.

[0029] In the heavy-duty truck electric drive assembly described above, the power coupling component 1 transmits the coupled power of multiple motors to the planetary gear system. The three planetary gear sets in the planetary gear system are connected in sequence. Planetary gear set 1 5 includes sun gear 1 51, planetary gear 1, planetary carrier 1 52 and ring gear 1 53. Planetary gear set 2 6 includes sun gear 2 61, planetary gear 2, planetary carrier 2 62 and ring gear 2 63. Planetary gear set 3 7 includes sun gear 3 71, planetary gear 3, planetary carrier 3 72 and ring gear 3 73. Sun gear 2 61 is fixed to sun gear 3 71, planetary carrier 1 52 is fixed to ring gear 2 63, and planetary carrier 2 62 is fixed to ring gear 3 73. Clutch set 3 is installed on sun gear 1 51 to disconnect or connect sun gear 1 51 with sun gear 2 61 and planetary carrier 2 62. Brakes are installed on the ring gears of the three planetary gear sets respectively to brake the three ring gears respectively. By clutching The control of the clutch group 3 and the brake can form a speed ratio switch of the planetary gear system, forming six forward gears and one reverse gear power on the output shaft 2, meeting the driving needs of various working conditions such as heavy-load escape, heavy-load acceleration, heavy-load high-speed driving, light-load escape, light-load overtaking, light-load high-speed cruising and reverse transmission of heavy trucks, improving the coverage rate of the motor's efficient operation range, reducing energy consumption, and reducing the requirements for the power of a single motor. The clutch group 3 and the brake are both installed in the planetary gear system to reduce the axial size of the drive assembly. The characteristics of the planetary gear system with a large speed ratio, the ability to cooperate with the brake to form a speed ratio switch, the compact structure and the easy integration of the multi-stage planetary gear system are utilized to realize the multi-gear expansion and compact layout of the drive assembly. The speed ratio of the planetary gear system is switched by opening and closing the clutch group and the brake to form a speed shift, improve the shift efficiency, reduce the shift shock, and improve the operating stability of the heavy truck. By utilizing the transmission characteristic that the positioning of the planet carrier in the planetary gear set will form a relative reverse rotation between the sun gear and the ring gear, the power output is transformed from the forward rotation input of the motor to the reverse rotation, thereby realizing reverse gear transmission. The power for both forward and reverse gears is generated by the forward rotation of the motor, avoiding reliance on the reverse rotation of the motor to achieve reverse gear, and avoiding the risk of oil seal failure and lubrication blind spots caused by motor reversal. An independent reverse gear is formed, thereby improving the structural reliability of the drive assembly under extreme working conditions.

[0030] The power coupling assembly 1 comprises at least two motors, an input shaft 11 connected to the motors, and a constant mesh shaft 12 parallel to and meshing with the input shaft 11. The constant mesh shaft 12 is coaxially connected to the sun gear 51. As shown in the figure, the two input shafts 11 couple the power of the two motors to the constant mesh shaft 12, forming a motor power coupling. The constant mesh shaft 12 transmits the power to the planetary gear train. Different numbers of motors can be configured according to the heavy truck's load capacity, application scenario, and installation space.

[0031] The constant mesh shaft 12 and sun gear 1 51 are coaxially connected via splines. This creates a split-shaft arrangement between the power coupling assembly 1 and the planetary gear train, supporting separate control of the two. This allows the number of starter motors to be adjusted based on road conditions during driving, accurately matching power output with driving requirements. This not only reduces energy consumption but also improves torque distribution accuracy between the wheels when escaping from muddy or steep slopes, enhancing the truck's maneuverability under adverse conditions.

[0032] The clutch assembly 3 includes a clutch A that cooperates with the second sun gear 61 and a clutch B that cooperates with the second planetary carrier 62. Both clutch A and clutch B are mounted on the first sun gear 51. When clutch A is activated, the first sun gear 51 engages with the second sun gear 52, and when clutch B is activated, the first sun gear 51 engages with the second planetary carrier 62. By controlling the opening and closing of clutch A, clutch B, brake C, brake D, and brake E, six forward gears and reverse gear power can be generated for the output shaft 2, such as Figures 2 to 8 As shown, a transmission structure for six forward gears and a reverse gear is formed on the output shaft 2. The dotted line in the figure represents the process of power being transmitted from the sun gear 51 to the output shaft 2.

[0033] When clutch A is started to connect sun gear 1 51 with sun gear 2 61 and brake E is started to fix ring gear 3 73, since brake C is not started, planetary gear set 1 5 cannot transmit, planetary carrier 2 62 and ring gear 3 73 are fixed together, and planetary gear set 2 6 cannot transmit, the power of coupled power assembly 1 is transmitted to sun gear 1 51, which directly drives sun gear 3 71 to rotate. After being decelerated by planetary gear set 3 7, the power is output from planetary carrier 3 72 and forms the first gear forward power on output shaft 2. The first gear forward power has the maximum torque and the minimum speed, which is suitable for heavy trucks to get out of trouble when going uphill or through muddy roads when heavily loaded. When clutch A is started to connect sun gear 1 51 with sun gear 2 61 and brake D is started to fix ring gear 2 63, planetary row 1 5 cannot transmit power because brake C is not activated. The power of coupled power assembly 1 is transmitted to sun gear 1 51, which in turn transmits power to sun gear 2 61 and sun gear 3 71. The power of sun gear 2 61 is transmitted to planetary carrier 3 72 via planetary carrier 2 62 and ring gear 3 72. The power of sun gear 3 71 is also transmitted to planetary carrier 3 72. The power converges on planetary carrier 3 72 to form second-gear forward power on output shaft 2. The torque of the second-gear forward power is less than that of the first-gear forward power, but the speed is greater than that of the first-gear forward power. This is suitable for heavy-load acceleration conditions such as overtaking when heavy trucks are accelerating under heavy load. When the starting clutch A connects the sun gear 1 51 with the sun gear 2 61 and the starting brake C fixes the ring gear 1 53, the power of the coupled power assembly 1 is transmitted to the sun gear 1 51, which drives the sun gear 2 61 and the sun gear 3 71 to rotate synchronously. The power of the sun gear 1 51 is transmitted to the planet carrier 1 52, which drives the ring gear 2 63 to rotate synchronously. The power of the ring gear 2 63 is transmitted to the planet carrier 2 62, and the power of the sun gear 2 61 is also transmitted to the planet carrier 2 62. The power is merged on the planet carrier 2 62, and the power of the planet carrier 2 62 is transmitted to the planet carrier 3 72 via the ring gear 3 73. The power of the sun gear 3 71 is also transmitted to the planet carrier 3 72. The power is merged on the planet carrier 3 72 to form the third forward gear power on the output shaft 2. The torque of the third forward gear power is less than that of the second forward gear power, and the speed is greater than that of the second forward gear power. It is suitable for heavy-load and high-speed driving conditions when heavy trucks are heavy-loaded and traveling at high speed on flat roads. When starting clutch A connects sun gear 1 51 with sun gear 2 61, and starting clutch B connects sun gear 1 51 with planet carrier 2 62, since brake C is not activated, planet row 1 5 cannot transmit, and the power of coupled power assembly 1 is transmitted to sun gear 1 51, which drives sun gear 2 61, planet carrier 2 62 and sun gear 3 71 to rotate synchronously. Since brake D is not activated, ring gear 2 63 is in a free state, and the power of sun gear 2 61 will not be transmitted to planet carrier 2 62. The power of planet carrier 2 62 is only directly driven by sun gear 1 51, and ring gear 3 73 rotates synchronously with planet carrier 2 62 and transmits power to planet carrier 3 72. The power of sun gear 3 71 is also transmitted to planet carrier 3 72. The power converges on planet carrier 3 72 to form the fourth forward gear power on the output shaft 2. The torque of the fourth forward gear power is less than that of the third forward gear power, and the speed is greater than that of the third forward gear power. It is suitable for light load escape conditions such as heavy trucks with light loads going uphill or passing through muddy roads; When the clutch B is started to connect the sun gear 1 51 with the planet carrier 2 62 and the brake C is started to fix the ring gear 1 53, the power of the power coupling assembly 1 is transmitted to the sun gear 1 51, and the power of the sun gear 1 51 is transmitted to the planet carrier 1 52. The planet carrier 1 52 drives the ring gear 2 63 to rotate synchronously, and the ring gear 2 63 transmits the rotation to the planet carrier 2 62. The sun gear 1 51 directly drives the planet carrier 2 62 to rotate synchronously. The power is combined with the planet carrier 2 62. The planet carrier 2 62 drives the ring gear 3 73 to rotate synchronously. The ring gear 3 73 transmits the power to the planet carrier 3 72, forming a fifth-speed forward power on the output shaft 2. The torque of the fifth-speed forward power is less than that of the fourth-speed forward power, and the speed is greater than that of the fourth-speed forward power. It is suitable for light-load acceleration conditions where heavy trucks accelerate under light loads. When clutch B is started to connect sun gear 1 51 with planet carrier 2 62 and brake D is started to fix ring gear 2 63, since brake C is not started, planet row 1 5 cannot transmit power, and the power of coupling power assembly 1 is transmitted to sun gear 1 51, which drives planet carrier 2 62 and ring gear 3 73 to rotate synchronously. The power of planet carrier 2 62 is transmitted to sun gear 2 61, which drives sun gear 3 71 to rotate synchronously. The power of sun gear 3 71 is transmitted to planet carrier 3 72, and the power of ring gear 3 73 is also transmitted to planet carrier 3 72. The power converges on planet carrier 3 72 to form the sixth forward gear power on the output shaft 2. The torque of the sixth forward gear power is less than that of the fifth forward gear power, and the speed is greater than that of the fifth forward gear power. It is suitable for light-load high-speed cruising conditions of heavy trucks with light loads on flat roads; When the starting brake C fixes the ring gear 1 53 and the starting brake E fixes the ring gear 3 73, the power of the coupled power assembly 1 is transmitted to the sun gear 1 51, and the sun gear 1 51 transmits the power to the planetary carrier 1 52. The planetary carrier 1 52 drives the ring gear 2 62 to rotate synchronously. Since the planetary carrier 2 62 is fixed to the ring gear 3 73, the planetary carrier 2 62 is also fixed and cannot rotate. The ring gear 2 62 will drive the sun gear 2 61 to rotate in the opposite direction, and the sun gear 2 61 drives the sun gear 3 71 to rotate in the opposite direction synchronously. The sun gear 3 71 transmits the power to the planetary carrier 3 72, so that the output shaft 2 rotates in the opposite direction with the planetary carrier 3 72, forming a reverse gear power on the output shaft 2 to meet the reverse gear transmission requirements of heavy trucks. When in reverse gear, the motor still rotates forward to input power to avoid the risk of oil seal failure and lubrication blind spots due to motor reversal, forming an independent reverse gear position, and improving the structural reliability of the drive assembly under extreme working conditions.

[0034] Sun gear 2 61 and sun gear 3 71 are respectively fixed to intermediate shaft 8, and sun gear 1 51 engages with intermediate shaft 8 upon activation of clutch A. Intermediate shaft 8 assembles sun gear 2 61 and sun gear 3 71 together, forming a coupling with clutch A. This simplifies the internal structure of the planetary gear train, and the sequentially connected structure of the three planetary gears is simpler, more compact, and easier to assemble.

[0035] The sun gear 1 51 is in the shape of a gear sleeve, with clutch A and clutch B respectively mounted within sun gear 1 51. The front end of planet carrier 2 62 extends into sun gear 1 51 and is radially aligned with clutch B. The front end of intermediate shaft 8 passes through planet carrier 2 62 and extends into sun gear 1 51 and is radially aligned with clutch A. Clutch A and clutch B are assembled within sun gear 1 51, with intermediate shaft 8 and planet carrier 2 62 also extending into sun gear 51, resulting in radial alignment between clutch A and the front end of intermediate shaft 8, and between clutch B and the front end of planet carrier 2 62. Activation of clutch A quickly couples intermediate shaft 8 with sun gear 1 51, thus forming a connection between sun gear 2 61 and sun gear 1 51. Activation of clutch B quickly couples planet carrier 2 62 with sun gear 1 51. Furthermore, the radial space between the coupled power assembly 1 and the planetary gear train is fully utilized to assemble clutch assembly 3, without increasing the axial dimension and improving the structural compactness.

[0036] It also includes a hydraulic buffer 9 that meshes with the output shaft 2. When the heavy truck encounters a long downhill road condition, the hydraulic buffer 9 can reduce the rotation speed of the output shaft 2 to reduce the vehicle speed and ensure driving safety when going down the long slope. At the same time, during the descent, the power of the output shaft 2 is transmitted to the coupled power assembly 1 through the planetary gear train 4 to charge the motor, forming a downhill power recovery.

[0037] The present invention also protects the shift control method of the electric drive assembly described above, which is characterized by: When the clutch pack 3 connects the sun gear 1 51 with the sun gear 2 61, the brake E is activated to fix the ring gear 3 73, and the forward first gear power is generated on the output shaft 2; When the clutch group 3 connects the sun gear 1 51 with the sun gear 2 61, the brake D is activated to fix the ring gear 2 62, and the forward second gear power is generated on the output shaft 2; When the clutch group 3 connects the sun gear 1 51 with the sun gear 2 61, the brake C is activated to fix the ring gear 1 53, and the forward third gear power is generated on the output shaft 2; When the clutch group 3 connects the sun gear 1 51 with the sun gear 2 61 and the planet carrier 2 62 respectively, the fourth gear forward power is generated on the output shaft 2; When the clutch group 3 connects the sun gear 1 51 with the planet carrier 2 62, the brake C is activated to fix the ring gear 1 53, and the fifth gear forward power is generated on the output shaft 2; When the clutch group 3 connects the sun gear 1 51 with the planet carrier 2 62, the brake D is activated to fix the ring gear 2 63, and the forward sixth gear power is formed on the output shaft; When brake C is activated to fix ring gear 1 53, brake E is activated to fix ring gear 3 73, and reverse gear power is generated on output shaft 2.

[0038] The shift control method described above can form a speed ratio switching of the planetary gear system by controlling the clutch group 3 and the brake, and form six forward gear powers and one reverse gear power on the output shaft 2, which can meet the driving requirements of various working conditions such as heavy-load escape, heavy-load acceleration, heavy-load high-speed driving, light-load escape, light-load overtaking, light-load high-speed cruising and reverse transmission of heavy trucks. The torque of the first forward gear power is the largest and the speed is the smallest, which is suitable for heavy-load escape conditions such as heavy trucks going uphill or through muddy roads when heavily loaded. The torque of the second forward gear power is less than that of the first forward gear power, and the speed is greater than that of the first gear power, which is suitable for heavy-load acceleration conditions such as heavy trucks accelerating when heavily loaded. The torque of the third forward gear power is less than that of the second forward gear power, and the speed is greater than that of the second forward gear power, which is suitable for heavy trucks traveling at high speed on flat roads when heavily loaded. The torque of the forward fourth gear power is less than that of the forward third gear power, and the speed is greater than that of the forward third gear power, which is suitable for light-load escape conditions such as heavy-duty trucks going uphill with a light load or passing through muddy roads. The torque of the forward fifth gear power is less than that of the forward fourth gear power, and the speed is greater than that of the forward fourth gear power, which is suitable for light-load acceleration conditions such as heavy-duty trucks accelerating with a light load. The torque of the forward sixth gear power is less than that of the forward fifth gear power, and the speed is greater than that of the forward fifth gear power, which is suitable for light-load and high-speed cruising conditions such as heavy-duty trucks cruising at high speed on flat roads with a light load. The reverse gear power meets the reverse transmission requirements of heavy-duty trucks. When in reverse gear, the motor still rotates forward to input power to avoid the risk of oil seal failure and lubrication blind spots due to motor reversal, forming an independent reverse gear position, and improving the structural reliability of the drive assembly under extreme working conditions.

[0039] Here, “when the clutch group 3 connects the sun gear 1 51 with the sun gear 2 61 ” means starting the clutch A to connect the sun gear 1 51 with the intermediate shaft 8 ; “When the clutch group 3 connects the sun gear 1 51 with the planet carrier 2 62 ” means starting the clutch B to connect the sun gear 1 51 with the planet carrier 2 62 ; “When the clutch group 3 connects the sun gear 1 51 with the sun gear 2 61 and the planet carrier 2 62 respectively” means: clutch A and clutch B are started synchronously to connect the sun gear 1 51 with the intermediate shaft 8 and the planet carrier 2 62 respectively.

[0040] Since the sun gear 2 61 and the sun gear 3 71 are fixed on the intermediate shaft 8 , the starting clutch A combines the sun gear 1 51 with the intermediate shaft 8 , which is equivalent to connecting the sun gear 1 51 with the sun gear 2 61 .

[0041] When clutch A is started to connect sun gear 1 51 with sun gear 2 61 and brake E is started to fix ring gear 3 73, since brake C is not started, planetary gear set 1 5 cannot transmit, planetary carrier 2 62 and ring gear 3 73 are fixed together, and planetary gear set 2 6 cannot transmit, the power of coupled power assembly 1 is transmitted to sun gear 1 51, which directly drives sun gear 3 71 to rotate. After being decelerated by planetary gear set 3 7, the power is output from planetary carrier 3 72 and forms the first gear forward power on output shaft 2. The first gear forward power has the maximum torque and the minimum speed, which is suitable for heavy trucks to get out of trouble when going uphill or through muddy roads when heavily loaded. When clutch A is started to connect sun gear 1 51 with sun gear 2 61 and brake D is started to fix ring gear 2 63, planetary row 1 5 cannot transmit power because brake C is not activated. The power of coupled power assembly 1 is transmitted to sun gear 1 51, which transmits power to sun gear 2 61 and sun gear 3 71. The power of sun gear 2 61 is transmitted to planetary carrier 3 72 via planetary carrier 2 62 and ring gear 3 72. The power of sun gear 3 71 is also transmitted to planetary carrier 3 72. The power converges on planetary carrier 3 72 to form second-gear forward power on output shaft 2. The torque of the second-gear forward power is less than that of the first-gear forward power, and the speed is greater than that of the first-gear forward power. This is suitable for heavy-load acceleration conditions where heavy trucks accelerate under heavy load. When the starting clutch A connects the sun gear 1 51 with the sun gear 2 61 and the starting brake C fixes the ring gear 1 53, the power of the coupled power assembly 1 is transmitted to the sun gear 1 51, which drives the sun gear 2 61 and the sun gear 3 71 to rotate synchronously. The power of the sun gear 1 51 is transmitted to the planet carrier 1 52, which drives the ring gear 2 63 to rotate synchronously. The power of the ring gear 2 63 is transmitted to the planet carrier 2 62, and the power of the sun gear 2 61 is also transmitted to the planet carrier 2 62. The power is merged on the planet carrier 2 62, and the power of the planet carrier 2 62 is transmitted to the planet carrier 3 72 via the ring gear 3 73. The power of the sun gear 3 71 is also transmitted to the planet carrier 3 72. The power is merged on the planet carrier 3 72 to form the third forward gear power on the output shaft 2. The torque of the third forward gear power is less than that of the second forward gear power, and the speed is greater than that of the second forward gear power. It is suitable for heavy-load and high-speed driving conditions when heavy trucks are heavy-loaded and traveling at high speed on flat roads. When starting clutch A connects sun gear 1 51 with sun gear 2 61, and starting clutch B connects sun gear 1 51 with planet carrier 2 62, since brake C is not activated, planet row 1 5 cannot transmit, and the power of coupled power assembly 1 is transmitted to sun gear 1 51, and sun gear 51 drives sun gear 2 61, planet carrier 2 62 and sun gear 3 71 to rotate synchronously. Since brake D is not activated, ring gear 2 63 is in a free state, and the power of sun gear 2 61 will not be transmitted to planet carrier 2 62. The power of planet carrier 2 62 is only directly driven by sun gear 1 51, and ring gear 3 73 rotates synchronously with planet carrier 2 62 and transmits power to planet carrier 3 72. The power of sun gear 3 71 is also transmitted to planet carrier 3 72. The power converges on planet carrier 3 72 to form the fourth forward gear power on the output shaft 2. The torque of the fourth forward gear power is less than that of the third forward gear power, and the speed is greater than that of the third forward gear power. It is suitable for light load escape conditions such as heavy trucks with light loads going uphill or passing through muddy roads; When the clutch B is started to connect the sun gear 1 51 with the planet carrier 2 62 and the brake C is started to fix the ring gear 1 53, the power of the power coupling assembly 1 is transmitted to the sun gear 1 51, and the power of the sun gear 1 51 is transmitted to the planet carrier 1 52. The planet carrier 1 52 drives the ring gear 2 63 to rotate synchronously, and the ring gear 2 63 transmits the rotation to the planet carrier 2 62. The sun gear 1 51 directly drives the planet carrier 2 62 to rotate synchronously. The power is combined with the planet carrier 2 62. The planet carrier 2 62 drives the ring gear 3 73 to rotate synchronously. The ring gear 3 73 transmits the power to the planet carrier 3 72, forming a fifth-speed forward power on the output shaft 2. The torque of the fifth-speed forward power is less than that of the fourth-speed forward power, and the speed is greater than that of the fourth-speed forward power. It is suitable for light-load acceleration conditions where heavy trucks accelerate under light loads. When clutch B is started to connect sun gear 1 51 with planet carrier 2 62 and brake D is started to fix ring gear 2 63, since brake C is not started, planet row 1 5 cannot transmit power, and the power of coupling power assembly 1 is transmitted to sun gear 1 51, which drives planet carrier 2 62 and ring gear 3 73 to rotate synchronously. The power of planet carrier 2 62 is transmitted to sun gear 2 61, which drives sun gear 3 71 to rotate synchronously. The power of sun gear 3 71 is transmitted to planet carrier 3 72, and the power of ring gear 3 73 is also transmitted to planet carrier 3 72. The power converges on planet carrier 3 72 to form the sixth forward gear power on the output shaft 2. The torque of the sixth forward gear power is less than that of the fifth forward gear power, and the speed is greater than that of the fifth forward gear power. It is suitable for light-load high-speed cruising conditions of heavy trucks with light loads on flat roads; When the starting brake C fixes the ring gear 1 53 and the starting brake E fixes the ring gear 3 73, the power of the coupled power assembly 1 is transmitted to the sun gear 1 51, and the sun gear 1 51 transmits the power to the planetary carrier 1 52. The planetary carrier 1 52 drives the ring gear 2 62 to rotate synchronously. Since the planetary carrier 2 62 is fixed to the ring gear 3 73, the planetary carrier 2 62 is also fixed and cannot rotate. The ring gear 2 62 will drive the sun gear 2 61 to rotate in the opposite direction, and the sun gear 2 61 drives the sun gear 3 71 to rotate in the opposite direction synchronously. The sun gear 71 transmits the power to the planetary carrier 3 72, causing the output shaft 2 to rotate in the opposite direction with the planetary carrier 3 72, forming a reverse gear power on the output shaft 2 to meet the reverse gear transmission requirements of heavy trucks. When in reverse gear, the motor still rotates forward to input power to avoid the risk of oil seal failure and lubrication blind spots due to motor reversal, forming an independent reverse gear position, and improving the structural reliability of the drive assembly under extreme working conditions.

[0042] 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 truck electric drive assembly includes a power coupling assembly, a planetary gear train, and an output shaft that are sequentially connected in a transmission manner. The power coupling assembly couples the power of multiple motors and is characterized by: It also includes a clutch group and a brake. The planetary gear system includes planetary row 1, planetary row 2 and planetary row 3 which are coaxially connected in sequence. The output shaft is connected to planetary carrier 3 of planetary row 3. The power coupling assembly is connected to sun gear 1 of planetary row 1. The clutch is assembled on sun gear 1 of planetary row 1. Sun gear 1 is connected to sun gear 2 and / or planetary carrier 2 of planetary row 2 through the clutch group. Planetary carrier 1 of planetary row 1 and ring gear 2 of planetary row 2 are fixed. Planetary carrier 2 of planetary row 2 and ring gear 3 of planetary row 3 are fixed. Sun gear 2 of planetary row 2 and sun gear 3 of planetary row 3 are fixed. Brake C, brake D and brake E are respectively installed on ring gear 1 of planetary row 1, ring gear 2 of planetary row 2 and ring gear 3 of planetary row 3. The power gear switching of the output shaft is controlled by the clutch group and the three brakes.

2. The heavy-duty truck electric drive assembly according to claim 1, characterized in that: The power coupling assembly includes at least two motors, an input shaft connected to the motor, and a constant meshing shaft parallel to and meshing with the input shaft, wherein the constant meshing shaft is coaxially connected to the sun gear.

3. The heavy-duty truck electric drive assembly according to claim 2, characterized in that: The constant meshing shaft and the sun gear 1 are coaxially connected through spline matching.

4. The heavy-duty truck electric drive assembly according to claim 2, characterized in that: The clutch group includes a clutch A that cooperates with the second sun gear and a clutch B that cooperates with the second planetary carrier. Both clutch A and clutch B are installed on the first sun gear. When the clutch A is started, the first sun gear is combined with the second sun gear, and when the clutch B is started, the first sun gear is combined with the second planetary carrier.

5. The heavy truck electric drive assembly according to claim 4, characterized in that: The sun gear 2 and the sun gear 3 are fixed on the intermediate shaft respectively, and the sun gear 1 is connected to the intermediate shaft when the clutch A is started.

6. The heavy truck electric drive assembly according to claim 5, characterized in that: The sun gear 1 is in the shape of a gear sleeve, clutch A and clutch B are respectively installed in the sun gear 1, the front end of the planet carrier 2 extends into the sun gear 1 and is radially aligned with the clutch B, and the front end of the intermediate shaft passes through the planet carrier 2 and extends into the sun gear 1 and is radially aligned with the clutch A.

7. The heavy truck electric drive assembly according to claim 1, characterized in that: Also included is a hydraulic damper engaged with the output shaft.

8. The shift control method for a heavy truck electric drive assembly according to any one of claims 1 to 7, characterized in that: When the clutch group connects sun gear 1 to sun gear 2, brake E is activated to fix ring gear 3, and forward first gear power is generated on the output shaft; When the clutch group connects sun gear 1 to sun gear 2, brake D is activated to fix ring gear 2, and forward second gear power is generated on the output shaft; When the clutch group connects sun gear 1 to sun gear 2, brake C is activated to fix ring gear 1, and forward third gear power is generated on the output shaft; When the clutch group connects sun gear 1 with sun gear 2 and planet carrier 2 respectively, the fourth gear forward power is formed on the output shaft; When the clutch group connects sun gear 1 to planet carrier 2, brake C is activated to fix ring gear 1, and forward fifth gear power is generated on the output shaft; When the clutch group connects sun gear 1 to planet carrier 2, brake D is activated to fix ring gear 2, and forward sixth gear power is generated on the output shaft; When brake C is activated to fix ring gear 1, brake E is activated to fix ring gear 3, and reverse gear power is generated on the output shaft.

9. The shift control method of the electric drive assembly according to claim 8, characterized in that: "When the clutch group connects sun gear 1 to sun gear 2" means starting clutch A to connect sun gear 1 to the intermediate shaft; "When the clutch group connects the sun gear 1 to the planet carrier 2" means starting the clutch B to connect the sun gear 1 to the planet carrier 2; "When the clutch group connects sun gear 1 to sun gear 2 and planet carrier 2 respectively" means: clutch A and clutch B are started synchronously to connect sun gear 1 to the intermediate shaft and planet carrier 2 respectively.

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