Multi-working-mode stepless speed change transmission system for tractor

Abstract

The invention relates to a multi-working-mode stepless speed change transmission system for a tractor, and relates to the field of tractor transmission structures. An outer gear ring of a stepless speed change device is in transmission connection with a first transmission shaft, the first transmission shaft is in transmission connection with a ninth gear and a tenth gear, and the ninth gear and the tenth gear rotationally sleeve a second transmission shaft; and the second transmission shaft is in clutch transmission connection with a driving wheel of the tractor. Two speed change sections are added on the basis of a stepless speed change device, the workable speed interval is expanded, conventional field operation can be efficiently dealt with, and meanwhile cost is reduced. Furthermore, a second motor clutch is installed on a second motor shaft, a sun gear clutch and an engine clutch are arranged on an engine shaft, an ultra-low-speed operation clutch is arranged on a second transmission shaft, and other transmission structures are arranged, so that the four working modes and the three-section gear shifting function can be achieved.

Description

A multi-mode continuously variable transmission system for tractors Technical Field

[0001] This invention relates to the field of tractor transmission structures, and more specifically to a continuously variable transmission system for tractors with multiple operating modes. Background Technology

[0002] Continuously variable transmission (CVT) technology for agricultural tractors previously relied heavily on hydrostatic transmission units to achieve stepless speed regulation. More recently, however, transmission technologies have emerged that utilize generators or electric motors for this purpose. These solutions are primarily based on the existing hydrostatic transmission architecture, resulting in a complex and bulky overall transmission structure.

[0003] For example, the continuously variable transmission device described in patent "2025111960440 - A continuously variable transmission device, tractor and tractor driving method" relies on only two motors and an engine to achieve continuously variable transmission. It has a small speed range that can be used for tractor operation, and the traction force is small at very low speeds (e.g., below 2 km / h), making it unsuitable for field work and unable to meet many operational needs. Summary of the Invention

[0004] The technical problem to be solved by this invention is how to further expand the working speed range.

[0005] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: A continuously variable transmission system for a tractor with multiple working modes includes a continuously variable transmission device, a first transmission shaft, a second transmission shaft, a ninth gear, a high-low gear clutch, and a tenth gear. The outer gear ring of the continuously variable transmission device is connected to the first transmission shaft. The first transmission shaft is connected to the ninth gear and the tenth gear. The ninth gear and the tenth gear are rotatably sleeved on the second transmission shaft and are connected to the second transmission shaft through the high-low gear clutch. The second transmission shaft is connected to the drive wheel of the tractor.

[0006] The beneficial effects of this invention are: by adding two speed ranges to the continuously variable transmission (CVT), the traction force at low speeds is increased, the working speed range is expanded, and it can efficiently handle routine field operations while reducing costs. Specifically, when the high / low gear clutch engages with the ninth gear, it is the routine operating gear, also known as the low gear; when the high / low gear clutch engages with the tenth gear, it is the road transport gear, also known as the high gear.

[0007] Based on the above technical solution, the present invention can be further improved as follows.

[0008] Furthermore, the continuously variable transmission (CVT) includes an engine, an engine shaft, a PTO shaft, a first motor, a second motor, a battery, a sun gear, a planetary gear assembly, and an external gear ring. The engine is drivenly connected to one end of the engine shaft, and the other end of the engine shaft is coaxially and fixedly connected to the planetary gear assembly. The sun gear is rotatably sleeved on the other end of the engine shaft and meshes with the inner side of the planetary gear assembly. The first motor is drivenly connected to the sun gear, and the outer side of the planetary gear assembly meshes with the external gear ring. The second motor is drivenly connected to the external gear ring. The external gear ring is rotatably sleeved on one end of the PTO shaft. The battery is electrically connected to both the first motor and the second motor.

[0009] The advantages of adopting the above-mentioned further solution are: it uses a planetary busbar mechanism in conjunction with two motors to achieve stepless speed regulation, resulting in a small size, simple structure, fewer gears, and lower cost. It also provides four operating modes. The parallel arrangement of the two motors is highly suitable for high-speed, high-power-density motors.

[0010] Furthermore, the continuously variable transmission system for the multi-working mode of the tractor also includes a first gear and an idler gear. The first motor is connected to the first gear, and the first gear is connected to the axle of the sun gear through the idler gear.

[0011] Furthermore, the continuously variable transmission system for the multi-working mode of the tractor also includes a second gear, a second motor clutch, a third gear, and a third drive shaft. The second gear and the third gear are rotatably mounted on the second motor shaft of the second motor. The second motor clutch is installed on the second motor shaft. The second gear and the third gear are connected to the second motor shaft through the second motor clutch. The second gear meshes with the external gear ring. The third gear is connected to the third drive shaft. The third drive shaft is connected to the second drive shaft.

[0012] The beneficial effect of adopting the above-mentioned further solution is that by setting a second motor clutch, the second motor can be switched to drive with the second gear or the third gear, or the path of the second motor outputting power to the outside can be disconnected.

[0013] Furthermore, the continuously variable transmission system for the multi-working mode of the tractor also includes an eleventh gear, a twelfth gear, and a fifteenth gear. The eleventh gear is fixed on the second drive shaft, and the twelfth and fifteenth gears are both fixed on the third drive shaft. The third gear meshes with the twelfth gear, and the fifteenth gear is connected to the eleventh gear.

[0014] The beneficial effects of adopting the above-mentioned further scheme are: the third gear and the third transmission shaft are driven by the meshing of the third gear and the twelfth gear, and the third transmission shaft and the second transmission shaft are driven by the meshing of the fifteenth gear and the eleventh gear.

[0015] Furthermore, the continuously variable transmission system for the multi-working-mode tractor also includes a sun gear clutch, which is mounted on the other end of the engine shaft, and the sun gear is engaged and disengaged from the engine shaft via the sun gear clutch.

[0016] The beneficial effect of adopting the above-mentioned further solution is that the sun gear clutch can connect the sun gear to the engine shaft to lock the planetary mechanism, or disconnect the sun gear from the engine shaft, allowing the planetary mechanism to operate normally. Therefore, this solution can achieve switching between hybrid continuously variable transmission (CVT) modes (parallel hybrid, series hybrid, and engine direct drive stepped transmission + single-motor hybrid).

[0017] Furthermore, the continuously variable transmission system for multi-working modes of tractors also includes an engine clutch and an engine intermediate shaft. The other end of the engine shaft is connected to one end of the engine intermediate shaft via the engine clutch. The other end of the engine intermediate shaft is provided with the sun gear clutch and the sun gear, and the other end of the engine intermediate shaft is coaxially and fixedly connected to the planetary gear assembly.

[0018] The beneficial effect of adopting the above-mentioned further solution is that, by setting an engine clutch, the engine's power can be connected or disconnected. This solution can realize the switching between hybrid continuously variable transmission (CVT) mode, series hybrid CVT mode, engine direct drive stepped transmission + single motor hybrid mode, and pure electric mode.

[0019] Furthermore, the continuously variable transmission system for the multi-working-mode tractor also includes a fourth gear, a fifth gear, and a sixth gear fixed on the first drive shaft. The fourth gear meshes with the gear ring shaft of the outer gear ring, the fifth gear meshes with the ninth gear, and the sixth gear meshes with the tenth gear.

[0020] The beneficial effects of adopting the above-mentioned further scheme are: the external gear ring and the first transmission shaft are connected by meshing with the gear ring shaft and the fourth gear; the transmission connection between the first transmission shaft and the ninth and tenth gears is achieved by meshing with the fifth gear and the ninth gear and meshing with the sixth gear and the tenth gear.

[0021] Furthermore, the continuously variable transmission system for multi-working modes of tractors also includes an ultra-low speed working clutch, a seventh gear, an eighth gear, a thirteenth gear, and a fourteenth gear. The ultra-low speed working clutch is mounted on the second drive shaft. The seventh gear is rotatably sleeved on the second drive shaft and is engaged and disengaged from the second drive shaft through the ultra-low speed working clutch. The eighth gear is coaxially and fixedly connected to the ninth gear. The thirteenth gear and the fourteenth gear are coaxially and fixedly connected and rotatably sleeved on the third drive shaft. The seventh gear meshes with the thirteenth gear, and the eighth gear meshes with the fourteenth gear.

[0022] The beneficial effects of adopting the above-mentioned further solution are: the ultra-low speed operating clutch can switch the engagement or disengagement of the seventh gear and the second drive shaft. When the seventh gear is engaged with the second drive shaft, it is in ultra-low speed operating gear. This solution has three shifting zones. When the vehicle needs to move short distances at low speeds, such as moving the vehicle around or attaching tools, the pure electric drive mode can be used in conjunction with the ultra-low speed operating gear. The vehicle can move slowly at low speeds, while avoiding long-distance driving in pure electric drive mode, which could damage the battery.

[0023] Furthermore, the continuously variable transmission system for the multi-working-mode tractor also includes a front drive connecting shaft, a sixteenth gear, a rear axle assembly, and a front axle assembly; both the front axle assembly and the rear axle assembly are provided with the drive wheel, the sixteenth gear is fixed on the front drive connecting shaft, both the sixteenth gear and the rear axle assembly are connected to the second drive shaft, and the front axle assembly is connected to the front drive connecting shaft.

[0024] The beneficial effect of adopting the above-mentioned further solution is that the second drive shaft transmits power to the drive wheels of the front axle assembly and the rear axle assembly respectively through the sixteenth gear and the rear axle assembly, thereby driving the tractor to move. Attached Figure Description

[0025] Figure 1 is a structural schematic diagram of a first embodiment of a multi-mode continuously variable transmission (CVT) for a tractor according to the present invention; Figure 2 is a structural schematic diagram of a second embodiment of a multi-mode CVT for a tractor according to the present invention; Figure 3 is a structural schematic diagram of a third embodiment of a multi-mode CVT for a tractor according to the present invention; Figure 4 is a structural schematic diagram of a fourth embodiment of a multi-mode CVT for a tractor according to the present invention; Figure 5 is a power transmission route diagram in the hybrid CVT mode of parallel hybrid electric power transmission; Figure 6 is a power transmission route diagram in the series hybrid CVT mode; Figure 7 is a power transmission route diagram in the engine direct drive stepped transmission + single motor hybrid mode; Figure 8 is a power transmission route diagram in the pure electric drive mode.

[0026] The components represented by each number in the attached diagram are listed below: 1. First motor; 2. Second motor; 3. Battery; 4. Engine shaft; 5. First gear; 6. Sun gear; 7. Planetary gear assembly; 8. External gear ring; 9. Second gear; 10. PTO shaft; 11. Engine clutch; 12. Sun gear clutch; 13. Second motor clutch; 14. Third gear; 15. First drive shaft; 16. Fourth gear; 17. Fifth gear; 18. Sixth gear; 19. Second drive shaft; 20. Ultra-low speed operating clutch; 21. Seventh gear; 22. Eighth gear; 23. Ninth gear; 24. High / low gear clutch; 25. Tenth gear; 26. Eleventh gear; 27. Third drive shaft; 28. Twelfth gear; 29. ​​Thirteenth gear; 30. Fourteenth gear; 31. Fifteenth gear; 32. Front drive connecting shaft; 33. Sixteenth gear. Detailed Implementation

[0027] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0028] As shown in Figure 1, this embodiment provides a continuously variable transmission (CVT) system for a tractor with multiple operating modes. It includes a CVT device, a first drive shaft 15, a second drive shaft 19, a ninth gear 23, a high / low gear clutch 24, and a tenth gear 25. The external gear ring 8 of the CVT device is connected to the first drive shaft 15. The first drive shaft 15 is connected to the ninth gear 23 and the tenth gear 25. The ninth gear 23 and the tenth gear 25 are rotatably mounted on the second drive shaft 19 and are connected to the second drive shaft 19 via the high / low gear clutch 24. The second drive shaft 19 is connected to the drive wheels of the tractor.

[0029] By adding two gear shifting sections to the continuously variable transmission (CVT), the traction at low speeds is increased, and the working speed range is expanded, enabling efficient handling of routine field operations while reducing costs. Specifically, when the high / low gear clutch 24 engages with the ninth gear 23, it is the regular operating gear, also known as the low gear; when the high / low gear clutch 24 engages with the tenth gear 25, it is the road transport gear, also known as the high gear.

[0030] Based on the above technical solution, the continuously variable transmission (CVT) includes an engine, an engine shaft 4, a PTO shaft 10, a first motor 1, a second motor 2, a battery 3, a sun gear 6, a planetary gear assembly 7, and an external gear ring 8. The engine is driven to one end of the engine shaft 4, and the other end of the engine shaft 4 is coaxially and fixedly connected to the planetary gear assembly 7. The sun gear 6 is rotatably sleeved on the other end of the engine shaft 4 and meshes with the inner side of the planetary gear assembly 7. The first motor 1 is driven to the sun gear 6, and the outer side of the planetary gear assembly 7 meshes with the external gear ring 8. The second motor 2 is driven to the external gear ring 8, and the external gear ring 8 is rotatably sleeved on one end of the PTO shaft 10. The battery 3 is electrically connected to the first motor 1 and the second motor 2 respectively.

[0031] This solution utilizes a planetary busbar mechanism in conjunction with two motors to achieve stepless speed regulation. It is compact, simple in structure, has few gears, and is low in cost. It also provides four operating modes. The parallel arrangement of the two motors is ideal for high-speed, high-power-density motors.

[0032] Specifically, the planetary gear assembly 7 includes a planetary gear carrier and planetary gears. The planetary gear carrier is coaxially and fixedly connected to the other end of the engine shaft 4. Multiple planetary gears are rotatably mounted on the planetary gear carrier. The planetary gears are located between the sun gear 6 and the external gear ring 8, and mesh with both of them respectively. The sun gear 6 and the external gear ring 8 are coaxially arranged, and the external gear ring 8 is fitted outside the sun gear 6.

[0033] Specifically, the first motor 1 and the second motor 2 are located on both sides of the engine shaft 4, and the shafts of the first motor 1 and the second motor 2 are parallel to the engine shaft 4.

[0034] The other end of the PTO shaft 10 is used to connect to the PTO.

[0035] Based on the above technical solution, the continuously variable transmission system for multi-working modes of tractors also includes a first gear 5 and an idler gear. The first motor 1 is connected to the first gear 5 in a transmission connection. The first gear 5 is connected to the axle of the sun gear 6 through the idler gear in a transmission connection.

[0036] Specifically, a hollow axle is connected to the center of the sun gear 6. The axle is rotated and fitted onto the other end of the engine shaft 4. A gear is fixed or integrally formed on the outside of the axle, and the gear meshes with the idler gear for transmission.

[0037] The continuously variable transmission (CVT) can achieve a hybrid powertrain continuously variable transmission mode. In this mode, the engine transmits power to the planetary gear assembly 7 via the engine shaft 4. The planetary gear assembly 7 then outputs power to the first drive shaft 15 via the external gear ring 8, and then to the second drive shaft 19 via the first drive shaft 15. The second drive shaft 19 then transmits power to the tractor's drive wheels. Referring to Figure 5, the rotation of the planetary gear assembly 7 drives the first motor 1 to rotate, thereby outputting electrical power to the first motor 1. By adjusting the speed of the first motor 1, the planetary gears are continuously adjusted while the engine speed remains constant. The rotational speed output by component 7 on the external gear ring 8; during the speed regulation process, the first motor 1 converts excess electrical power into electrical energy and transmits it to the second motor 2, which in turn converts the electrical energy into electrical power and outputs it to the external gear ring 8; or, the rotation of the external gear ring 8 drives the second motor 2 to rotate, thereby outputting electrical power to the second motor 2; by adjusting the rotational speed of the second motor 2, the rotational speed output by the external gear ring 8 is steplessly regulated while the engine speed remains constant; during the speed regulation process, the second motor 2 converts excess electrical power into electrical energy and transmits it to the first motor 1, which in turn converts the electrical energy into electrical power and outputs it to the external gear ring 8 through the sun gear 6.

[0038] Specifically, "by adjusting the speed of the first motor 1, while keeping the engine speed constant, the speed output of the planetary gear assembly 7 on the external gear ring 8 is continuously adjusted." This means that by energizing the coil of the first motor 1, the resistance to the rotation of the coil of the first motor 1 is adjusted, thereby adjusting the rotational resistance of the planetary gear assembly 7, and thus adjusting its output speed on the external gear ring 8. Similarly, "by adjusting the speed of the second motor 2, while keeping the engine speed constant, the speed output of the external gear ring 8 is continuously adjusted." This means that by adjusting the resistance to the rotation of the coil of the second motor 2, the speed of the external gear ring 8 is adjusted.

[0039] In the continuously variable transmission (CVT) mode of the hybrid electric vehicle, specifically as shown in Figure 5, the engine's mechanical power flows through the planetary gear carrier, then through the planetary gears to the external ring gear 8, and is finally output to the drive wheels; the electrical power flows through the planetary gears to the sun gear 6, and is output to the first motor 1. By adjusting the speed of the first motor 1, the speed output of the planetary gear assembly 7 on the external ring gear 8 can be continuously adjusted while keeping the engine speed constant. During the speed adjustment process, the first motor 1 converts excess power into electrical energy, which is transmitted to the second motor 2. The second motor 2 converts the electrical energy into torque, which is output to the external ring gear 8 and merged with the mechanical power before being output to the drive wheels. During this period, the torque output of the second motor 2 can be rapidly increased or decreased to adapt to complex changes in the drive wheels and maintain a constant vehicle speed. During the adjustment of the second motor 2, if the torque of the second motor 2 suddenly increases and the required power exceeds the generating power of the first motor 1, power can be temporarily drawn from the battery 3 to meet the vehicle's power requirements; if the torque of the second motor 2 suddenly decreases and the required power is less than the generating power of the first motor 1, the excess electrical energy can be stored in the battery 3 for future use. That is, under this operating condition, the first motor 1 is equivalent to a generator, and the second motor 2 is equivalent to a drive motor.

[0040] Under certain speed regulation conditions, the power generation roles of the first motor 1 and the second motor 2 may be switched. The power transmission path is as follows: In this case, the mechanical power flow does not change, but the second motor 2 becomes a generator and the first motor 1 becomes a drive motor. The direction of the electrical power flow is opposite to that of the previous condition.

[0041] During most field and engineering operations, the vehicle operates in hybrid continuously variable transmission (CVT) mode, which offers high efficiency and a wide speed range under heavy loads. In CVT mode, the gears can be further adjusted by switching the engagement position of the high / low gear clutch 24, enabling two-stage gear changes. The high / low gear clutch 24 can be switched to engage with the ninth gear 23 to engage the conventional operating gear; or, it can be switched to engage with the tenth gear 25 to engage the road transport gear.

[0042] As shown in Figure 2, in Embodiment 2, based on Embodiment 1, the continuously variable transmission system for a tractor with multiple working modes further includes a second gear 9, a second motor clutch 13, a third gear 14, and a third transmission shaft 27. The second gear 9 and the third gear 14 are rotatably mounted on the second motor shaft of the second motor 2. The second motor clutch 13 is installed on the second motor shaft. The second gear 9 and the third gear 14 are connected to the second motor shaft via the second motor clutch 13. The second gear 9 meshes with the external gear ring 8. The third gear 14 is connected to the third transmission shaft 27. The third transmission shaft 27 is connected to the second transmission shaft 19.

[0043] By setting the second motor clutch 13, the second motor 2 can be switched to drive the second gear 9 or the third gear 14, or the path for the second motor 2 to output power can be disconnected.

[0044] Based on the above technical solution, the continuously variable transmission system for multi-working modes of tractors further includes an eleventh gear 26, a twelfth gear 28, and a fifteenth gear 31. The eleventh gear 26 is fixed on the second transmission shaft 19, the twelfth gear 28 and the fifteenth gear 31 are both fixed on the third transmission shaft 27, the third gear 14 meshes with the twelfth gear 28, and the fifteenth gear 31 is connected to the eleventh gear 26.

[0045] The third gear 14 and the third drive shaft 27 are connected by the meshing of the third gear 14 and the twelfth gear 28. The third drive shaft 27 and the second drive shaft 19 are connected by the meshing of the fifteenth gear 31 and the eleventh gear 26.

[0046] Based on the above technical solution, the continuously variable transmission system for multi-working modes of tractors also includes a sun gear clutch 12, which is installed at the other end of the engine shaft 4, and the sun gear 6 is connected to the engine shaft 4 via the sun gear clutch 12.

[0047] The sun gear clutch 12 can connect the sun gear 6 to the engine shaft 4 to lock the planetary mechanism, or disconnect the sun gear 6 from the engine shaft 4, allowing the planetary mechanism to operate normally. Therefore, this solution can switch between hybrid continuously variable transmission (CVT) modes (parallel hybrid, series hybrid, and engine direct drive stepped transmission + single-motor hybrid).

[0048] The power transmission routes for each mode are as follows: 1. Hybrid continuously variable transmission (CVT) mode with parallel electric and combined hydraulic transmissions (CVT) as shown in Figure 2. The power transmission route in this mode is shown in Figure 5. The vehicle operates in the hybrid CVT mode with parallel electric and combined hydraulic transmissions during most field and engineering operations. This mode has high efficiency and a large speed range under heavy load conditions. The working principle is as follows (the same as the principle of the hybrid CVT mode with parallel electric and combined hydraulic transmissions in Example 1): The sun gear clutch 12 is in neutral, and the second motor clutch 13 is engaged to the right (the second motor clutch 13 engages the second motor shaft of the second motor 2 with the second gear 9 for transmission). The engagement position of the high and low gear clutches 24 can be selected according to the required vehicle speed.

[0049] The engine power is divided into two paths via the planetary gear carrier. Mechanical power flows through the planetary gears to the external ring gear 8, and is ultimately output to the drive wheels. Electrical power flows through the planetary gears to the sun gear 6, and is output to the first motor 1. By adjusting the speed of the first motor 1, the speed output by the planetary gear assembly 7 on the external ring gear 8 can be continuously adjusted while keeping the engine speed constant. During speed adjustment, the first motor 1 converts excess power into electrical energy, which is transmitted to the second motor 2. The second motor 2 converts the electrical energy into torque, which is output to the external ring gear 8 and merges with the mechanical power before being output to the drive wheels. During this period, the torque output of the second motor 2 can be rapidly increased or decreased to adapt to complex changes in the drive wheels and maintain a constant vehicle speed. During the adjustment of the second motor 2, if the torque of the second motor 2 suddenly increases, and the required power exceeds the generating power of the first motor 1, power can be temporarily drawn from the battery 3 to meet the vehicle's power needs. If the torque of the second motor 2 suddenly decreases, and the required power is less than the generating power of the first motor 1, the excess electrical energy can be stored in the battery 3 for future use.

[0050] 2. The “Series Hybrid CVT Mode” and “Engine Direct Drive Stepped Transmission + Single Motor Hybrid Mode” are shown in Figure 2. When the vehicle is performing road transfer and road transport operations, the vehicle switches between the “Series Hybrid CVT Mode” and the “Engine Direct Drive Stepped Transmission + Single Motor Hybrid Mode” according to the vehicle speed and load. This can improve road driving comfort and reduce fuel consumption. The working principle is as follows: The power transmission route in the Series Hybrid CVT Mode is shown in Figure 6. When the vehicle starts and the vehicle speed is low, the transmission works in the Series Hybrid CVT Mode. At this time, the sun gear clutch 12 is engaged to the right, locking the planetary mechanism, and the second motor clutch 13 is engaged to the left (so that the second motor shaft of the second motor 2 engages with the third gear 14 for transmission). The high and low gear clutches 24 are both in the neutral position.

[0051] All the power provided by the engine drives the first motor 1 to generate electricity. The generated electricity drives the second motor 2, which directly propels the vehicle to start and travel at low speed. At this time, the engine load is relatively light and it can operate at its most economical speed. Specifically, referring to Figure 6, the power transmission path is as follows: engine shaft 4 - sun gear clutch 12 - sun gear 6 - first gear 5 - first motor 1 - second motor 2 - second motor clutch 13 - third gear 14 - twelfth gear 28 - third drive shaft 27 - fifteenth gear 31 - eleventh gear 26 - second drive shaft 19, and finally transmitted to the drive wheels through the second drive shaft 19.

[0052] As the vehicle speed increases and the engine load increases, in order to avoid the disadvantage of low efficiency of the series hybrid system affecting fuel consumption, the transmission switches to the engine direct drive stepped transmission + single motor hybrid mode. The power transmission route is shown in Figure 7. At this time, the sun gear clutch 12 remains stationary (in the right engagement position), the second motor clutch is in neutral to disconnect the second motor 2, and the high-low gear clutch 24 engages the low gear to the left.

[0053] At this point, the planetary gear set is locked and loses its transmission capability. Power is directly transmitted to the mechanical stepped transmission section, and output after deceleration. Since the power transmission does not pass through the electric transmission path, the transmission efficiency is the highest at this time. The first motor 1 can share part of the load according to the load conditions. For example, when the road load suddenly increases, it draws power from the battery 3 to provide some additional power. When the road load suddenly decreases, it absorbs excess engine power to generate electricity and stores it in the battery 3, maintaining the stability of the engine load and reducing the extra fuel consumption caused by frequent fluctuations in engine load. At the same time, the first motor 1 can provide a power recovery function to avoid kinetic energy waste and further reduce fuel consumption. Specifically, referring to Figure 7, the power transmission path is: engine shaft 4 - sun gear clutch 12 - sun gear 6 - planetary gear assembly 7 - external gear ring 8 - fourth gear 16 - first drive shaft 15 - fifth gear 17 - ninth gear 23 - second drive shaft 19.

[0054] As the vehicle speed increases further, the high / low gear clutch 24 can be engaged to the right to switch to a higher gear.

[0055] Based on Example 2, as shown in Figure 3, Example 3 further includes an engine clutch 11 and an engine intermediate shaft for a multi-working-mode continuously variable transmission system for a tractor. The other end of the engine shaft 4 is connected to one end of the engine intermediate shaft via the engine clutch 11. The other end of the engine intermediate shaft is provided with the sun gear clutch 12 and the sun gear 6, and the other end of the engine intermediate shaft is coaxially and fixedly connected to the planetary gear assembly 7.

[0056] In this embodiment, the engine power can be connected or disconnected by setting the engine clutch 11. This solution can realize the switching between hybrid continuously variable transmission (CVT) mode, series hybrid CVT mode, engine direct drive stepped transmission + single motor hybrid mode, and pure electric mode.

[0057] Based on the above technical solution, the continuously variable transmission system for multi-working modes of tractors also includes a fourth gear 16, a fifth gear 17 and a sixth gear 18 fixed on the first transmission shaft 15. The fourth gear 16 meshes with the gear ring shaft of the external gear ring 8, the fifth gear 17 meshes with the ninth gear 23, and the sixth gear 18 meshes with the tenth gear 25.

[0058] The external gear ring 8 is driven by the gear ring shaft and the fourth gear 16 through meshing; the transmission connection between the first transmission shaft 15 and the ninth gear 23 and the tenth gear 25 is achieved by the meshing of the fifth gear 17 with the ninth gear 23 and the meshing of the sixth gear 18 with the tenth gear 25.

[0059] Specifically, a hollow gear shaft is coaxially fixed on the side of the outer gear ring 8 facing away from the planetary gear assembly 7. The gear shaft is rotatably sleeved on the PTO shaft 10. A gear shaft gear is coaxially fixed on the outside of the gear shaft. The gear shaft gear meshes with the fourth gear 16, realizing the meshing transmission between the fourth gear 16 and the gear shaft of the outer gear ring 8.

[0060] The solution in this embodiment can switch between hybrid continuously variable transmission (CVT) mode, series hybrid CVT mode, engine direct drive stepped transmission + single motor hybrid mode, and pure electric mode.

[0061] In the hybrid continuously variable transmission (CVT) mode, the series hybrid CVT mode, and the engine direct drive stepped transmission + single motor hybrid mode, the engine clutch 11 is engaged, and the other end of the engine shaft 4 is connected to the engine intermediate shaft through the engine clutch 11. The transmission principle in the above three modes is the same as in Embodiment 2.

[0062] The principle of pure electric mode is as follows: The engine is off, engine clutch 11 disengages from the engine, sun gear clutch 12 engages to the right and locks the planetary gear mechanism, and second motor clutch 13 is in neutral, disengaging the second motor 2. At this time, the first motor 1 draws power directly from the motor to drive the vehicle. High / low gear clutch 24 can engage high or low gear. The power transmission path is: battery 3 - first motor 1 - first gear 5 - sun gear 6 - planetary gear assembly 7 - external gear ring 8 - fourth gear 16 - first drive shaft 15 - fifth gear 17 or sixth gear - second drive shaft 19.

[0063] Based on Example 3, as shown in Figure 4, Example 4 of the continuously variable transmission system for a tractor with multiple working modes further includes an ultra-low speed working clutch 20, a seventh gear 21, an eighth gear 22, a thirteenth gear 29, and a fourteenth gear 30. The ultra-low speed working clutch 20 is mounted on the second drive shaft 19. The seventh gear 21 is rotatably sleeved on the second drive shaft 19 and is engaged and disengaged from the second drive shaft 19 through the ultra-low speed working clutch 20. The eighth gear 22 is coaxially and fixedly connected to the ninth gear 23. The thirteenth gear 29 and the fourteenth gear 30 are coaxially and fixedly connected and rotatably sleeved on the third drive shaft 27. The seventh gear 21 meshes with the thirteenth gear 29, and the eighth gear 22 meshes with the fourteenth gear 30.

[0064] In this embodiment, the ultra-low speed operating clutch 20 can switch the engagement or disengagement of the seventh gear 21 with the second drive shaft 19. When the seventh gear 21 is engaged with the second drive shaft 19, it is in ultra-low speed operating mode. This scheme has three shifting sections. When the vehicle needs to move short distances at low speeds, such as moving the vehicle or attaching tools, the pure electric drive mode can be used in conjunction with the ultra-low speed operating mode. The vehicle can move slowly at low speeds, while avoiding long-distance driving in pure electric drive mode, which could damage the battery.

[0065] The solution in this embodiment can switch between the following four modes and has three-segment shifting: hybrid continuously variable transmission (CVT) mode, series hybrid CVT mode, engine direct drive stepped transmission + single motor hybrid mode, and pure electric mode.

[0066] The power transmission routes for each mode are as follows: 1. Hybrid continuously variable transmission (CVT) mode with parallel electric power supply as shown in Figure 5. The vehicle operates in hybrid continuously variable transmission mode with parallel electric power supply during most field operations and engineering operations. This mode has high efficiency and a large speed range under heavy load conditions. The working principle is as follows (the same as the principle of hybrid continuously variable transmission mode with parallel electric power supply in Example 1): The sun gear clutch 12 is in neutral, and the second motor clutch 13 is engaged to the right (the second motor clutch 13 engages the second motor shaft of the second motor 2 with the second gear 9 for transmission). The engagement position of the high and low gear clutches 24 can be selected according to the required vehicle speed.

[0067] The engine power is divided into two paths via the planetary gear carrier. The engine transmits power to the planetary gear assembly 7 through the engine shaft 4. The planetary gear assembly 7 outputs power to the first drive shaft 15 through the external gear ring 8, and then to the second drive shaft 19 through the first drive shaft 15. The second drive shaft 19 then transmits power to the tractor's drive wheels. The electrical power is transmitted to the sun gear 6 through the planetary gears and output to the first motor 1. By adjusting the speed of the first motor 1, the speed output by the planetary gear assembly 7 on the external gear ring 8 can be steplessly adjusted while keeping the engine speed constant. During the speed adjustment process, the first motor 1 converts excess power into electrical energy, which is transmitted to the second motor 2. The second motor 2 converts the electrical energy into torque, which is output to the external gear ring 8 and merged with the mechanical power before being output to the drive wheels. During this period, the torque output of the second motor 2 can be rapidly increased or decreased to adapt to complex changes in the drive wheels and maintain a constant vehicle speed. During the adjustment of the second motor 2, if the torque of the second motor 2 suddenly increases and the required power exceeds the power output of the first motor 1, power can be temporarily drawn from the battery 3 to meet the power requirements of the vehicle; if the torque of the second motor 2 suddenly decreases and the required power is less than the power output of the first motor 1, the excess electrical energy can be stored in the battery 3 for future use.

[0068] 2. As shown in Figure 4, the “Series Hybrid CVT Mode” and the “Engine Direct Drive Stepped Transmission + Single Motor Hybrid Mode” are used when the vehicle is performing road transfer and road transport operations. The vehicle switches between the “Series Hybrid CVT Mode” and the “Engine Direct Drive Stepped Transmission + Single Motor Hybrid Mode” according to the vehicle speed and load. This can improve road driving comfort and reduce fuel consumption. The working principle is as follows: The power transmission route in the Series Hybrid CVT Mode is shown in Figure 6. When the vehicle starts and the vehicle speed is low, the transmission works in the Series Hybrid CVT Mode. At this time, the sun gear clutch 12 is engaged to the right, locking the planetary mechanism, and the second motor clutch 13 is engaged to the left (so that the second motor shaft of the second motor 2 engages with the third gear 14 and drives). The high and low gear clutches 24 and the ultra-low speed working clutch 20 are both in the neutral position.

[0069] All the power provided by the engine drives the first motor 1 to generate electricity. The generated electricity drives the second motor 2, which directly propels the vehicle to start and travel at low speed. At this time, the engine load is relatively light and it can operate at its most economical speed. Specifically, referring to Figure 6, the power transmission path is as follows: engine shaft 4 - sun gear clutch 12 - sun gear 6 - first gear 5 - first motor 1 - second motor 2 - second motor clutch 13 - third gear 14 - twelfth gear 28 - third drive shaft 27 - fifteenth gear 31 - eleventh gear 26 - second drive shaft 19, and finally transmitted to the drive wheels through the second drive shaft 19.

[0070] As the vehicle speed increases and the engine load increases, in order to avoid the disadvantage of low efficiency of the series hybrid system affecting fuel consumption, the transmission switches to the engine direct drive stepped transmission + single motor hybrid mode. The power transmission route is shown in Figure 7. At this time, the sun gear clutch 12 remains stationary (in the right engagement position), the second motor clutch is in neutral to disconnect the second motor 2, the ultra-low speed working clutch 20 remains in neutral, and the high-low gear clutch 24 engages the low gear to the left.

[0071] At this point, the planetary gear set is locked and loses its transmission capability. Power is directly transmitted to the mechanical stepped transmission section, and output after deceleration. Since the power transmission does not pass through the electric transmission path, the transmission efficiency is the highest at this time. The first motor 1 can share part of the load according to the load conditions. For example, when the road load suddenly increases, it draws power from the battery 3 to provide some additional power. When the road load suddenly decreases, it absorbs excess engine power to generate electricity and stores it in the battery 3, maintaining the stability of the engine load and reducing the extra fuel consumption caused by frequent fluctuations in engine load. At the same time, the first motor 1 can provide a power recovery function to avoid kinetic energy waste and further reduce fuel consumption. Specifically, as shown in Figure 7, the power transmission path is: engine shaft 4 - sun gear clutch 12 - sun gear 6 - planetary gear assembly 7 - external gear ring 8 - fourth gear 16 - first drive shaft 15 - fifth gear 17 - ninth gear 23 - second drive shaft 19.

[0072] As the vehicle speed increases further, the high / low gear clutch 24 can be engaged to the right to switch to a higher gear.

[0073] 3. The principle of pure electric mode is as follows: As shown in Figure 8, when the vehicle needs to move short distances at low speeds, such as for repositioning or attaching tools, the engine is off, the engine clutch 11 disengages, the sun gear clutch 12 engages to the right and locks the planetary mechanism, the second motor clutch 13 is in neutral and disengages the second motor 2, the ultra-low speed working clutch 20 engages to the right in ultra-low speed working gear, and the high / low gear clutch 24 is in neutral. At this time, the first motor 1 draws power directly from the motor to drive the vehicle. Simultaneously, the stepped transmission engages the ultra-low speed working gear, which has a very low maximum speed, allowing the vehicle to move slowly at low speeds. This also prevents users from using pure electric drive mode for long distances, which could damage the battery. The power transmission path is as follows: Battery 3 - First Motor 1 - First Gear 5 - Sun Gear 6 - Planetary Gear Assembly 7 - External Gear Ring 8 - Fourth Gear 16 - First Drive Shaft 15 - Fifth Gear 17 - Ninth Gear 23 - Eighth Gear 22 - Fourteenth Gear 30 - Thirteenth Gear 29 - Seventh Gear 21 - Second Drive Shaft 19, and finally transmitted to the drive wheel through the second drive shaft 19.

[0074] In Embodiment 5, based on any of the above embodiments, the continuously variable transmission system for a tractor with multiple working modes further includes a front drive connecting shaft 32, a sixteenth gear 33, a rear axle assembly, and a front axle assembly; both the front axle assembly and the rear axle assembly are provided with the drive wheel, the sixteenth gear 33 is fixed on the front drive connecting shaft 32, both the sixteenth gear 33 and the rear axle assembly are connected to the second drive shaft 19, and the front axle assembly is connected to the front drive connecting shaft 32.

[0075] The second drive shaft 19 transmits power to the drive wheels of the front axle assembly and the rear axle assembly respectively through the sixteenth gear 33 and the rear axle assembly, thereby driving the tractor.

[0076] Based on any of the above embodiments, the shifting method can be either a mechanical AMT or a wet clutch.

[0077] This invention discloses a multi-mode continuously variable transmission (CVT) for tractors. The segmented shifting section is arranged on a four-shaft configuration with three gears, corresponding to ultra-low speed operation (0-2 km / h), regular operation (5-14 km / h), and road transport operation (>20 km / h). The ultra-low speed gear reuses the low-gear (ninth gear 23) and utilizes the direct-drive shaft of the second motor as support, achieving three-stage reduction within a limited space and compensating for insufficient drive torque during ultra-low speed operation. This transmission system can be configured with either two segments or a full three-segment configuration, depending on the target market's operational requirements. This transmission system offers multiple operating modes, can handle various working conditions, and has strong adaptability.

[0078] Among them, the hybrid continuously variable transmission (CVT) mode is particularly suitable for heavy-duty operations. The engine operates at its optimal fuel consumption speed, ensuring stable load and low fuel consumption. It can output maximum traction at speeds above 2 km / h, making it highly adaptable to various operations. Traction is lower below 2 km / h; if operation is required under these conditions, the ultra-low speed working gear can be selected.

[0079] When transporting on roads, the series hybrid continuously variable transmission (CVT) mode is used for starting and low-speed driving to cope with low-speed conditions and frequent start-stop operations, such as rural roads. The series hybrid system can ensure that the engine is not working or directly enters the optimal fuel consumption condition when it is working, thereby minimizing fuel consumption.

[0080] When entering provincial highways or national highways where high speeds can be driven for extended periods, the low efficiency of the series hybrid transmission leads to high fuel consumption. In this case, the system can switch to an engine-driven direct-drive stepped transmission + single-motor hybrid mode. The engine-driven direct-drive stepped transmission mode, without the electric motor involved in the transmission, offers the highest efficiency and lowest fuel consumption. However, its limited gears make it unsuitable for handling changing road conditions (uphill, downhill, acceleration, deceleration, etc.). The single-motor hybrid mode compensates for and balances engine power to adapt to these conditions, while also providing a kinetic energy recovery mode to further reduce fuel consumption. Compared to existing continuously variable transmission (CVT) solutions, the direct-drive stepped transmission + single-motor hybrid mode improves driving efficiency over long distances at high speeds (above 30 km / h).

[0081] In the description of this invention, it should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first" and "second" may explicitly or implicitly include at least one of those features.

[0082] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0083] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0084] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A continuously variable transmission system for a tractor with multiple operating modes, comprising a continuously variable transmission device, characterized in that, It also includes a first drive shaft (15), a second drive shaft (19), a ninth gear (23), a high-low gear clutch (24), and a tenth gear (25). The outer gear ring (8) of the continuously variable transmission is connected to the first drive shaft (15). The first drive shaft (15) is connected to the ninth gear (23) and the tenth gear (25). The ninth gear (23) and the tenth gear (25) are rotatably mounted on the second drive shaft (19) and are connected to the second drive shaft (19) through the high-low gear clutch (24). The second drive shaft (19) is connected to the drive wheel of the tractor.

2. The continuously variable transmission system for a tractor with multiple operating modes according to claim 1, characterized in that, The continuously variable transmission (CVT) includes an engine, an engine shaft (4), a PTO shaft (10), a first motor (1), a second motor (2), a battery (3), a sun gear (6), a planetary gear assembly (7), and an external gear ring (8). The engine is driven to one end of the engine shaft (4), and the other end of the engine shaft (4) is coaxially and fixedly connected to the planetary gear assembly (7). The sun gear (6) is rotatably sleeved on the other end of the engine shaft (4) and meshes with the inner side of the planetary gear assembly (7). The first motor (1) is driven to the sun gear (6), and the outer side of the planetary gear assembly (7) meshes with the external gear ring (8). The second motor (2) is driven to the external gear ring (8), and the external gear ring (8) is rotatably sleeved on one end of the PTO shaft (10). The battery (3) is electrically connected to the first motor (1) and the second motor (2) respectively.

3. A continuously variable transmission system for a tractor with multiple operating modes according to claim 2, characterized in that, It also includes a first gear (5) and an idler gear. The first motor (1) is connected to the first gear (5) in a transmission connection. The first gear (5) is connected to the axle of the sun gear (6) in a transmission connection through the idler gear.

4. A continuously variable transmission system for a tractor with multiple operating modes according to claim 2, characterized in that, It also includes a second gear (9), a second motor clutch (13), a third gear (14) and a third transmission shaft (27). The second motor (2) has the second gear (9) and the third gear (14) rotatably mounted on the second motor shaft. The second motor clutch (13) is installed on the second motor shaft. The second gear (9) and the third gear (14) are connected to the second motor shaft through the second motor clutch (13). The second gear (9) meshes with the external gear ring (8). The third gear (14) is connected to the third transmission shaft (27). The third transmission shaft (27) is connected to the second transmission shaft (19).

5. A continuously variable transmission system for a tractor with multiple operating modes according to claim 4, characterized in that, It also includes an eleventh gear (26), a twelfth gear (28) and a fifteenth gear (31). The eleventh gear (26) is fixed on the second transmission shaft (19). The twelfth gear (28) and the fifteenth gear (31) are both fixed on the third transmission shaft (27). The third gear (14) meshes with the twelfth gear (28) for transmission. The fifteenth gear (31) and the eleventh gear (26) are connected for transmission.

6. A continuously variable transmission system for a tractor with multiple operating modes according to claim 4, characterized in that, It also includes a sun gear clutch (12), which is installed at the other end of the engine shaft (4), and the sun gear (6) is connected to the engine shaft (4) via the sun gear clutch (12).

7. A continuously variable transmission system for a tractor with multiple operating modes according to claim 6, characterized in that, It also includes an engine clutch (11) and an engine intermediate shaft. The other end of the engine shaft (4) is connected to one end of the engine intermediate shaft via the engine clutch (11). The other end of the engine intermediate shaft is provided with the sun gear clutch (12) and the sun gear (6). The other end of the engine intermediate shaft is coaxially fixedly connected to the planetary gear assembly (7).

8. A continuously variable transmission system for a tractor with multiple operating modes according to claim 7, characterized in that, It also includes a fourth gear (16), a fifth gear (17) and a sixth gear (18) fixed on the first transmission shaft (15). The fourth gear (16) meshes with the gear ring shaft of the external gear ring (8), the fifth gear (17) meshes with the ninth gear (23), and the sixth gear (18) meshes with the tenth gear (25).

9. A continuously variable transmission system for a tractor with multiple operating modes according to claim 8, characterized in that, It also includes an ultra-low speed operating clutch (20), a seventh gear (21), an eighth gear (22), a thirteenth gear (29), and a fourteenth gear (30). The ultra-low speed operating clutch (20) is mounted on the second drive shaft (19). The seventh gear (21) is rotatably sleeved on the second drive shaft (19) and is connected to the second drive shaft (19) via the ultra-low speed operating clutch (20). The eighth gear (22) is coaxially fixedly connected to the ninth gear (23). The thirteenth gear (29) and the fourteenth gear (30) are coaxially fixedly connected and rotatably sleeved on the third drive shaft (27). The seventh gear (21) meshes with the thirteenth gear (29), and the eighth gear (22) meshes with the fourteenth gear (30).

10. A continuously variable transmission system for a tractor with multiple operating modes according to claim 1, characterized in that, It also includes a front drive connecting shaft (32), a sixteenth gear (33), a rear axle assembly and a front axle assembly; the front axle assembly and the rear axle assembly are both provided with the drive wheel, the sixteenth gear (33) is fixed on the front drive connecting shaft (32), the sixteenth gear (33) and the rear axle assembly are both connected to the second drive shaft (19), and the front axle assembly is connected to the front drive connecting shaft (32).

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