Transmission system and tractor

Abstract

The utility model relates to the technical field of tractors, and discloses a transmission system and a tractor. The input end of the hydraulic stepless speed change device is in transmission connection with the engine, and the section shifting clutch is arranged to be capable of selectively connecting the engine to the high-speed gear section shifting driving gear or the low-speed gear section shifting driving gear in a transmission mode. The first input end and the second input end of the first planetary gear mechanism are correspondingly in transmission connection with the output end of the hydraulic stepless speed change device and the high-speed gear section shifting driving gear respectively; the first input end and the second input end of the second planetary gear mechanism are correspondingly in transmission connection with the output end of the hydraulic stepless speed change device and the low-speed gear section shifting driving gear respectively; the rotating speeds of the first input end and the second input end of the first planetary gear mechanism are correspondingly the same as those of the first input end and the second input end of the second planetary gear mechanism respectively, and the output ends of the first planetary gear mechanism and the second planetary gear mechanism are in transmission connection to the driving wheel. The transmission system can avoid section changing impact, and impact-free section changing is achieved.

Description

Transmission system and tractor Technical Field

[0001] This utility model belongs to the field of tractor technology, specifically relating to a transmission system and a tractor having the same. Background Technology

[0002] The hydraulic-mechanical continuously variable transmission (CVT) consists of a hydraulic speed regulating mechanism, a mechanical speed changing mechanism, and a power distribution and merging mechanism. It is a new type of transmission that combines hydraulic power flow and mechanical power flow in parallel. By combining mechanical power and hydraulic power, it can achieve efficient stepless transmission, allowing the engine to operate in the economic range, improving fuel economy, and also has the function of power shifting. It has become one of the development directions of tractor transmission systems.

[0003] Currently, hydraulic mechanical continuously variable transmissions (CVTs) require shifting gears during the continuously variable transmission process. However, during this shifting process, the operating states of different components change, resulting in differences in the input speed transmitted to the manifold mechanism. This causes interaction forces between the components inside the manifold mechanism, which in turn triggers impacts, affecting the lifespan of the internal components of the hydraulic mechanical CVT and the driving experience. Summary of the Invention

[0004] The purpose of this invention is to provide a transmission system and tractor that solves the problem of impact easily caused during the shifting process of existing hydraulic mechanical continuously variable transmissions.

[0005] To achieve the above objectives, this utility model provides a transmission system, comprising: a hydraulic continuously variable transmission (CVT), the input end of which is connected to an engine; a shift clutch, configured to selectively connect the engine to a high-speed shift drive gear or a low-speed shift drive gear; a first planetary gear mechanism, the first input end and the second input end of which are respectively connected to the output end of the CVT and the high-speed shift drive gear; and a second planetary gear mechanism, the first input end and the second input end of which are respectively connected to the output end of the CVT and the low-speed shift drive gear, wherein the rotational speeds of the first and second input ends of the first planetary gear mechanism are the same as those of the first and second input ends of the second planetary gear mechanism, and the output ends of the first and second planetary gear mechanisms are connected to a drive wheel.

[0006] In some embodiments, the hydraulic continuously variable transmission includes a hydraulic pump driven by the engine and a hydraulic motor driven by the hydraulic pump.

[0007] In some embodiments, the transmission system further includes a sun gear shaft, which is configured to rotate synchronously by the hydraulic motor; the first planetary gear mechanism includes a first sun gear disposed on the sun gear shaft, a first planet carrier with a converging gear, and a first ring gear, the converging gear meshing with the high-speed shift drive gear; the second planetary gear mechanism includes a second sun gear disposed on the sun gear shaft, a second planet carrier, and a second ring gear, the second ring gear having an external gear meshing with the low-speed shift drive gear; the first ring gear and the second planet carrier are connected to the drive wheel as output terminals.

[0008] In some embodiments, the first gear ring and the second planetary carrier are connected to each other via a spline sleeve, so that the first gear ring is connected to the drive wheel via the spline sleeve and the second planetary carrier.

[0009] In some embodiments, the transmission system further includes a travel transmission mechanism for drivingly connecting the output ends of the first planetary gear mechanism and the second planetary gear mechanism to the drive wheel. The travel transmission mechanism includes: a reversing drive gear, which is drivingly connected to the output ends of the first planetary gear mechanism and the second planetary gear mechanism; a reversing double gear, which is disposed on the output shaft of the reversing clutch, and the large gear of the reversing double gear meshes with the reversing drive gear; a reversing idler gear, which meshes with the small gear of the reversing double gear; a reversing driven gear, which meshes with the reversing idler gear; and a reversing synchronizer, which can selectively connect to the reversing drive gear or the reversing driven gear, and the output end of the reversing synchronizer is drivingly connected to the drive wheel.

[0010] In some embodiments, the travel transmission mechanism further includes: a bevel gear shaft, which is arranged parallel to the input shaft of the shift clutch, and one end of the bevel gear shaft is drive-connected to the output end of the commutation synchronizer; a driving bevel gear, which is disposed at the other end of the bevel gear shaft; a driven bevel gear, which meshes with the driving bevel gear; a third planetary gear mechanism, in which the third sun gear of the third planetary gear mechanism is drive-connected to the output end of the driven bevel gear, and the third planet carrier of the third planetary gear mechanism is drive-connected to the left wheel; and a fourth planetary gear mechanism, in which the fourth sun gear of the fourth planetary gear mechanism is drive-connected to the output end of the driven bevel gear, and the fourth planet carrier of the fourth planetary gear mechanism is drive-connected to the right wheel.

[0011] In some embodiments, the transmission system further includes a hydraulic steering device comprising: a steering drive gear located outside the shift clutch; a steering idler gear meshing with the steering drive gear; a steering driven gear meshing with the steering idler gear; a steering pump with its input end connected to the steering driven gear; a steering motor driven by the steering pump; and a hydraulic steering mechanism with its input end connected to the steering motor and its output end connected to the third ring gear of the third planetary gear mechanism and the fourth ring gear of the fourth planetary gear mechanism, respectively.

[0012] In some embodiments, the hydraulic steering mechanism includes: a multi-stage hydraulic gear set, the input end of which is operatively connected to the output end of the steering motor; a first steering gear, which is connected to the output end of the multi-stage hydraulic gear set and meshes with the third gear ring; and a second steering gear, which is connected to the output end of the multi-stage hydraulic gear set and meshes with the fourth gear ring via a hydraulic idler wheel, such that the third gear ring and the fourth gear ring rotate at the same speed but in opposite directions.

[0013] In some embodiments, the transmission system further includes a working power transmission assembly, which is drive-connected to the output shaft of the shift clutch and connected to the working mechanism.

[0014] The second aspect of this utility model provides a tractor, the tractor including the transmission system described in any of the above embodiments.

[0015] Through the above technical solution, the hydraulic power of the hydraulic continuously variable transmission (CVT) can be transmitted to the first input end of the first planetary gear mechanism and the first input end of the second planetary gear mechanism, making their rotational speeds the same. When the shift clutch is connected to the low-speed shift drive gear, the engine power is transmitted to the second input end of the second planetary gear mechanism through the shift clutch and the low-speed shift drive gear. When the shift clutch is connected to the high-speed shift drive gear, the engine power is transmitted to the second input end of the first planetary gear mechanism through the shift clutch and the high-speed shift drive gear. The second input ends of the first and second planetary gear mechanisms achieve the same rotational speed through the gear ratio. Therefore, when the shift clutch switches between the low-speed and high-speed shift drive gears, the input ends of the first and second planetary gear mechanisms rotate at the same speed, avoiding shift shock and achieving shock-free shifting, thus ensuring the lifespan of the transmission system components and the driving experience.

[0016] Other features and advantages of this invention will be described in detail in the following detailed description section. Attached Figure Description

[0017] The accompanying drawings are provided to further illustrate the embodiments of the present invention and form part of the specification. They are used together with the following detailed description to explain the embodiments of the present invention, but do not constitute a limitation thereof. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without any inventive effort. In the drawings:

[0018] Figure 1 is a schematic diagram of the transmission system according to an embodiment of the present disclosure.

[0019] Explanation of reference numerals in the attached figures

[0020] 1. Hydraulic continuously variable transmission (CVT); 2. Hydraulic pump; 3. Hydraulic motor; 4. Engine; 5. Shock absorber; 6. Shift clutch; 7. High-speed shift drive gear; 8. Low-speed shift drive gear; 9. Sun gear shaft; 10. First planetary gear mechanism; 11. First planetary carrier; 12. First ring gear; 13. Spline sleeve; 14. Second planetary gear mechanism; 15. Second planetary carrier; 16. Second ring gear; 17. Reversing drive gear; 18. Reversing double gear; 19. Reversing idler gear; 20. Reversing driven gear; 21. Reversing synchronizer; 22. Drive bevel gear; 23. Driven bevel gear; 24. Drive wheel; 25. Third planetary gear mechanism; 26. Third sun gear; 27. Third planetary carrier; 28. Third ring gear; 29. ​​Fourth planetary gear mechanism; 30. Steering idler gear; 31. Steering gear. Driven gear; 32. Steering pump; 33. Steering motor; 34. First steering gear; 35. Second steering gear; 36. Hydraulic idler gear; 37. First-stage hydraulic drive gear; 38. First-stage hydraulic driven gear; 39. Second-stage hydraulic drive gear; 40. Hydraulic double gear; 41. Third-stage hydraulic driven gear; 42. Fourth-stage hydraulic drive gear; 43. Fourth-stage hydraulic driven gear; 44. PTO clutch; 45. High-speed gear working power drive gear; 46. Low-speed gear working power drive gear; 47. High-speed gear working power driven gear; 48. Low-speed gear working power driven gear; 49. Engaging sleeve; 50. Bevel gear shaft; 51. Fourth sun gear; 52. Fourth planetary carrier; 53. Fourth gear ring; 54. Steering drive gear; S1. Working power output drive shaft; S2. Working power output driven shaft. Detailed Implementation

[0021] The specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the scope of this utility model.

[0022] The transmission system according to this utility model is described below with reference to the accompanying drawings.

[0023] Referring to Figure 1, this utility model provides a transmission system including a hydraulic continuously variable transmission (CVT) 1, a shift clutch 6, a first planetary gear mechanism 10, and a second planetary gear mechanism 14. The input end of the hydraulic CVT 1 is connected to the engine 4. The shift clutch 6 is configured to selectively connect the engine 4 to a high-speed shift drive gear 7 or a low-speed shift drive gear 8. The first and second input ends of the first planetary gear mechanism 10 are respectively connected to the output end of the hydraulic CVT 1 and the high-speed shift drive gear 7. The first and second input ends of the second planetary gear mechanism 14 are respectively connected to the output end of the hydraulic CVT 1 and the low-speed shift drive gear 8. The rotational speeds of the first and second input ends of the first planetary gear mechanism 10 are the same as the rotational speeds of the first and second input ends of the second planetary gear mechanism 14. The output ends of the first and second planetary gear mechanisms 10 and 14 are connected to the drive wheel 24.

[0024] The power from engine 4 is transmitted in two ways: one to the hydraulic continuously variable transmission (CVT) 1 and the other to the shifting clutch 6. The hydraulic power from the CVT 1 and the mechanical power from the shifting clutch 6 can converge to either the first planetary gear mechanism 10 or the second planetary gear mechanism 14, and then the output ends of the first planetary gear mechanism 10 and the second planetary gear mechanism 14 are connected to the drive wheel 24 to achieve power transmission and drive the vehicle. The hydraulic power from the CVT 1 can be transmitted to the first input end of the first planetary gear mechanism 10 and the first input end of the second planetary gear mechanism 14, so that the first input ends of the first planetary gear mechanism 10 and the first input ends of the second planetary gear mechanism 14 rotate at the same speed. When the shift clutch 6 is engaged with the low-speed shift drive gear 8, the power of the engine 4 is transmitted to the second input end of the second planetary gear mechanism 14 through the shift clutch 6 and the low-speed shift drive gear 8. When the shift clutch 6 is engaged with the high-speed shift drive gear 7, the power of the engine 4 is transmitted to the second input end of the first planetary gear mechanism 10 through the shift clutch 6 and the high-speed shift drive gear 7. The second input end of the first planetary gear mechanism 10 and the second input end of the second planetary gear mechanism 14 achieve the same speed through the gear transmission ratio. Therefore, when the shift clutch 6 switches between the low-speed shift drive gear 8 and the high-speed shift drive gear 7, the input ends of the first planetary gear mechanism 10 and the second planetary gear mechanism 14 rotate at the same speed, avoiding shift shock and achieving shock-free shifting, thus ensuring the life of the internal components of the transmission system and the driving experience. Furthermore, the transmission system transmits power through two planetary gear mechanisms, eliminating the need for a secondary gearbox. Due to the stepless speed change characteristics of the hydraulic continuously variable transmission device 1, the output speed of the hydraulic continuously variable transmission device 1 can be continuously and steplessly adjusted, thereby realizing automatic stepless speed change across the entire speed range of the vehicle. With fewer gears, operation is more convenient.

[0025] To achieve the transmission of hydraulic power, the hydraulic continuously variable transmission (CVT) 1 includes a hydraulic pump 2 driven by the engine 4 and a hydraulic motor 3 driven by the hydraulic pump 2. The power from the engine 4 is transmitted to the hydraulic pump 2, thereby transferring the mechanical power of the engine 4 to the hydraulic pump 2. The hydraulic pump 2 then drives the hydraulic motor 3 to rotate, achieving the transmission of hydraulic power. This enables stepless speed regulation and forward / reverse rotation at the first input end of the first planetary gear mechanism 10 and the second input end of the second planetary gear mechanism 14, allowing the transmission system to better match the operating conditions of the engine 4, improving the vehicle's power and fuel economy, and achieving high transmission efficiency. Furthermore, the hydraulic CVT 1 can automate gear shifting, reducing the driver's workload.

[0026] In order to prevent the hydraulic pump 2 of the hydraulic continuously variable transmission 1 from being damaged by the vibration energy generated by the engine 4 during operation, a shock absorber 5 is used to connect the output end of the engine 4 and the hydraulic pump 2 so as to transmit the power of the engine 4 to the hydraulic continuously variable transmission 1.

[0027] In one implementation, the shock absorber 5 is a torsional shock absorber, which is fixed to the flywheel of the engine 4 by bolts.

[0028] In one implementation, the hydraulic pump 2 is a variable displacement pump, and the hydraulic motor 3 is a fixed displacement motor. When the rotational speed of the hydraulic pump 2 is constant, the rotational speed of the hydraulic motor 3 will also change when the displacement of the hydraulic pump 2 changes. The rotational speed of the hydraulic motor 3 can be adjusted within the range of -X rpm to +X rpm, thereby realizing the stepless speed change of the hydraulic continuously variable transmission device 1.

[0029] In some embodiments, the hydraulic pump 2 has an input shaft connected to the torsional damper at its front end and an output shaft at its rear end. The input shaft and the output shaft are fixedly connected to each other to enable the power output of the engine 4 to the shift clutch 6.

[0030] In some embodiments, the transmission system further includes a sun gear shaft 9, which is configured to be driven synchronously by a hydraulic motor 3; the first planetary gear mechanism 10 includes a first sun gear mounted on the sun gear shaft 9, a first planet carrier 11 with a converging gear, and a first ring gear 12, the converging gear meshing with a high-speed shift drive gear 7; the second planetary gear mechanism 14 includes a second sun gear mounted on the sun gear shaft 9, a second planet carrier 15, and a second ring gear 16, the second ring gear 16 having an external gear meshing with a low-speed shift drive gear 8; the first ring gear 12 and the second planet carrier 15 are connected to the drive wheel 24 as output terminals.

[0031] The first input end of the first planetary gear mechanism 10 is the first sun gear, and the second input end is the first planet carrier 11; the first input end of the second planetary gear mechanism 14 is the second sun gear, and the second input end is the second ring gear 16. The sun gear shaft 9 is driven to rotate by the hydraulic motor 3, realizing stepless speed regulation and forward and reverse rotation, so that the first sun gear and the second sun gear mounted on the sun gear shaft 9 rotate at the same speed, thus achieving the same speed at the first input end of the first planetary gear mechanism 10 and the first input end of the second planetary gear mechanism 14. When the vehicle starts, it is in a low gear. The shift clutch 6 is connected to the low gear shift drive gear 8. The low gear shift drive gear 8 rotates and drives the second ring gear 16 of the second planetary gear mechanism 14 to rotate through meshing with the external gear. The hydraulic power of the hydraulic continuously variable transmission 1 and the mechanical power of the engine 4 converge in the second planetary gear mechanism 14 and are transmitted to the drive wheel 24 through the second planetary carrier 15 of the second planetary gear mechanism 14 to drive the drive wheel 24 to move. When the shift clutch 6 shifts gears, the shift clutch 6 disengages from the low gear shift drive gear 8 and connects to the high gear shift drive gear 7. The high gear shift drive gear 7 meshes with the converging gear, thereby driving the first planetary carrier 11 equipped with the converging gear to rotate synchronously. The hydraulic power of the hydraulic continuously variable transmission 1 and the mechanical power of the engine 4 converge in the first planetary gear mechanism 10 and are transmitted to the drive wheel 24 through the first ring gear 12 of the first planetary gear mechanism 10 to drive the drive wheel 24 to move. By setting the first planetary gear mechanism 10 and the second planetary gear mechanism 14 with appropriate gear parameters, the rotational speed of the first planetary carrier 11 and the rotational speed of the second ring gear 16 can always remain the same, thus achieving the same rotational speed at the second input end of the first planetary gear mechanism 10 and the second input end of the second planetary gear mechanism 14. When the shifting clutch 6 switches between the low-speed shifting drive gear 8 and the high-speed shifting drive gear 7, since the input ends of the first planetary gear mechanism 10 and the second planetary gear mechanism 14 rotate at the same speed, shock-free shifting of the shifting clutch 6 can be achieved.

[0032] In some embodiments, the transmission system includes a hydraulic control device capable of controlling the connection between the shift clutch 6 and the low-speed shift drive gear 8 or the high-speed shift drive gear 7.

[0033] In some embodiments, both the confluence gear and the external gear located on the second gear ring 16 are external meshing cylindrical gears.

[0034] In some embodiments, the output shaft of the hydraulic motor 3 is connected to the sun gear shaft 9 via a spline.

[0035] To transmit power from the first planetary gear mechanism 10 to the drive wheel 24, the first ring gear 12 of the first planetary gear mechanism 10 and the second planetary carrier 15 of the second planetary gear mechanism 14 can be connected to the drive wheel 24 via transmission. Alternatively, the first ring gear 12 and the second planetary carrier 15 can be connected to each other via a spline sleeve 13, allowing the first ring gear 12 to be transmitted to the drive wheel 24 through the spline sleeve 13 and the second planetary carrier 15. Because the first ring gear 12 and the second planetary carrier 15 are connected via the spline sleeve 13, the rotational speed of the first ring gear 12 is the same as that of the second planetary carrier 15, thus transmitting the power of the first ring gear 12 to the drive wheel 24.

[0036] In some embodiments, the transmission system further includes a travel transmission mechanism for drivingly connecting the output ends of the first planetary gear mechanism 10 and the second planetary gear mechanism 14 to the drive wheel 24. The travel transmission mechanism includes a reversing drive gear 17, a reversing double gear 18, a reversing idler gear 19, a reversing driven gear 20, and a reversing synchronizer 21. The reversing drive gear 17 is drivenly connected to the output ends of the first planetary gear mechanism 10 and the second planetary gear mechanism 14. The reversing double gear 18 is located on the output shaft of the reversing clutch 6. The large gear of the reversing double gear 18 meshes with the reversing drive gear 17. The reversing idler gear 19 meshes with the small gear of the reversing double gear 18. The reversing driven gear 20 meshes with the reversing idler gear 19. The reversing synchronizer 21 can selectively connect to the reversing drive gear 17 or the reversing driven gear 20. The output end of the reversing synchronizer 21 is drivenly connected to the drive wheel 24. When the reversing synchronizer 21 pushes forward and connects with the reversing drive gear 17, the power from the output end of the first planetary gear mechanism 10 or the second planetary gear mechanism 14 is directly transmitted to the reversing synchronizer 21 through the reversing drive gear 17, and then to the drive wheel 24 connected to the output end of the reversing synchronizer 21, driving the vehicle forward. When the reversing synchronizer 21 pushes backward and connects with the reversing driven gear 20, the power from the output end of the first planetary gear mechanism 10 or the second planetary gear mechanism 14 is transmitted to the drive wheel 24 connected to the output end of the reversing synchronizer 21 through the reversing drive gear 17, the reversing double gear 18, the reversing idler gear 19, the reversing driven gear 20, and the reversing synchronizer 21 connected to the reversing driven gear 20, driving the vehicle backward. Through the cooperation of the reversing drive gear 17, the reversing double gear 18, the reversing idler gear 19, the reversing driven gear 20, and the reversing synchronizer 21, reversing is achieved, enabling the vehicle to move forward or backward, thus driving the vehicle.

[0037] In some embodiments, the reversing drive gear 17 is connected to the second planetary carrier 15 via a spline, and the reversing double gear 18 is rotatably connected to the output shaft of the shift clutch 6.

[0038] In some embodiments, the walking transmission mechanism further includes a bevel shaft 50, a driving bevel gear 22, a driven bevel gear 23, a third planetary gear mechanism 25, and a fourth planetary gear mechanism 29. The bevel shaft 50 is arranged parallel to the input shaft of the shift clutch 6, and one end of the bevel shaft 50 is drivenly connected to the output end of the commutator synchronizer 21. The driving bevel gear 22 is disposed at the other end of the bevel shaft 50. The driven bevel gear 23 meshes with the driving bevel gear 22. The third sun gear 26 of the third planetary gear mechanism 25 is drivenly connected to the output end of the driven bevel gear 23. The third planetary carrier 27 of the third planetary gear mechanism 25 is drivenly connected to the left wheel. The fourth sun gear 51 of the fourth planetary gear mechanism 29 is drivenly connected to the output end of the driven bevel gear 23. The fourth planetary carrier 52 of the fourth planetary gear mechanism 29 is drivenly connected to the right wheel. The power of the commutator synchronizer 21 is transmitted through the bevel shaft 50 and the driven bevel gear 23 that meshes with the driving bevel gear 22 to the third sun gear 26 of the third planetary gear mechanism 25 and the fourth sun gear 51 of the fourth planetary gear mechanism 29. The power then drives the left and right wheels of the vehicle to rotate and move through the third planet carrier 27 of the third planetary gear mechanism 25 and the fourth planet carrier 52 of the fourth planetary gear mechanism 29.

[0039] In some embodiments, the transmission system further includes a hydraulic steering device, which includes a steering drive gear 54, a steering idler gear 30, a steering driven gear 31, a steering pump 32, a steering motor 33, and a hydraulic steering mechanism. The steering drive gear 54 is located outside the shift clutch 6. The steering idler gear 30 meshes with the steering drive gear 54, and the steering driven gear 31 meshes with the steering idler gear 30. The input end of the steering pump 32 is driven by the steering driven gear 31. The steering motor 33 is driven by the steering pump 32. The input end of the hydraulic steering mechanism is driven by the steering motor 33. The output end of the hydraulic steering mechanism is driven by the third ring gear 28 of the third planetary gear mechanism 25 and the fourth ring gear 53 of the fourth planetary gear mechanism 29, respectively. The shift clutch 6 rotates under the drive of the engine 4, thereby driving the steering drive gear 54 located outside the shift clutch 6 to rotate, and driving the steering idler gear 30 and the steering driven gear 31 meshing with the steering idler gear to rotate, driving the steering pump 32 to rotate. The rotation of the steering pump 32 generates hydraulic power to drive the steering motor 33 to work. The steering motor 33 transmits power to the hydraulic steering mechanism and drives the third gear ring 28 and the fourth gear ring 53 to rotate, thereby realizing the steering of the vehicle.

[0040] In some embodiments, the steering pump 32 is connected to the steering driven gear 31 via a spline, and the steering motor 33 is mounted on the outside of the gearbox.

[0041] The third ring gear 28 and the fourth ring gear 53 rotate at the same speed but in opposite directions, which makes the speed of the third planetary carrier 27 different from that of the fourth planetary carrier 52. This, in turn, makes the speed of the left wheel different from that of the right wheel, enabling the vehicle to turn or make a U-turn. The driver can turn the vehicle and make a U-turn on the spot simply by operating the steering wheel, without having to reverse, which greatly reduces labor intensity and improves work efficiency.

[0042] In some embodiments, the hydraulic steering mechanism includes a multi-stage hydraulic gear set, a first steering gear 34, and a second steering gear 35. The input end of the multi-stage hydraulic gear set is connected to the output end of the steering motor 33. The first steering gear 34 is connected to the output end of the multi-stage hydraulic gear set and meshes with a third gear ring 28. The second steering gear 35 is connected to the output end of the multi-stage hydraulic gear set and meshes with a fourth gear ring 53 via a hydraulic idler wheel 36, ensuring that the third gear ring 28 and the fourth gear ring 53 rotate at the same speed but in opposite directions. The power of the steering motor 33 is transmitted to the first steering gear 34 and the second steering gear 35 through the multi-stage hydraulic gear set. The meshing of the gears ensures that the third gear ring 28 and the fourth gear ring 53 rotate at the same speed, while the hydraulic idler wheel 36 ensures that the third gear ring 28 and the fourth gear ring 53 rotate in opposite directions, thereby enabling vehicle steering and U-turns.

[0043] When the hydraulic steering mechanism is not working, the rotational speeds of the third ring gear 28 and the fourth ring gear 53 are 0, and the third sun gear 26 and the fourth sun gear 51 drive the third planetary carrier 27 and the fourth planetary carrier 52 to rotate at the same speed, enabling the vehicle to travel in a straight line. When the hydraulic steering mechanism is working, the rotational speeds of the third sun gear 26 and the fourth sun gear 51 are the same, and the rotational speeds of the third ring gear 28 and the fourth ring gear 53 are the same but in opposite directions. After merging, they drive the rotation of the third planetary carrier 27 and the fourth planetary carrier 52, but the rotational speeds of the third planetary carrier 27 and the fourth planetary carrier 52 are different, that is, the rotational speeds of the left wheel and the right wheel are different, thereby enabling the vehicle to turn. By changing the rotational speeds of the steering motor 33 and the third sun gear 26 and the fourth sun gear 51, the vehicle can turn according to different turning radii. When the third sun gear 26 and the fourth sun gear 51 are not rotating and the steering motor 33 is working, the third ring gear 28 and the fourth ring gear 53 rotate at the same speed in opposite directions, and the third planetary carrier 27 and the fourth planetary carrier 52 also rotate at the same speed in opposite directions, thereby enabling the vehicle to turn around on the spot.

[0044] In some embodiments, the multi-stage hydraulic gear set includes a first-stage hydraulic gear set, a second-stage hydraulic gear set, a third-stage hydraulic gear set, and a fourth-stage hydraulic gear set. The first-stage hydraulic gear set includes a first-stage hydraulic drive gear 37 that is driven and connected to the output end of the steering motor 33, and a first-stage hydraulic driven gear 38 that meshes with the first-stage hydraulic drive gear 37. The second-stage hydraulic gear set includes a second-stage hydraulic drive gear 39 that is driven and connected to the first-stage hydraulic driven gear 38, and a hydraulic double gear 40. The large gear of the hydraulic double gear 40 meshes with the second-stage hydraulic drive gear 39. The third-stage hydraulic gear set includes a third-stage hydraulic driven gear 41 that meshes with the small gear of the hydraulic double gear 40. The fourth-stage hydraulic gear set includes a fourth-stage hydraulic drive gear 42 that is driven and connected to the third-stage hydraulic driven gear 41, and a fourth-stage hydraulic driven gear 43 that meshes with the fourth-stage hydraulic drive gear 42. The fourth-stage hydraulic driven gear 43 is coaxially connected to the first steering gear 34 and the second steering gear 35.

[0045] In some embodiments, the primary hydraulic drive gear 37 is connected to the steering motor 33 via a spline, the secondary hydraulic drive gear 39 is connected to the primary hydraulic driven gear 38 via a spline, and the hydraulic double gear 40 is mounted on the shaft of the first steering gear 34 and can rotate freely relative to the shaft.

[0046] In some embodiments, the transmission system further includes a working power transmission assembly, which is driveably connected to the output shaft of the shift clutch 6 and to the working mechanism. The shift clutch 6 drives the working mechanism through the working power transmission assembly.

[0047] In some embodiments, the working power transmission assembly includes a working power input shaft, a working power output drive shaft S1, and a working power output driven shaft S2. The working power input shaft is driven to the output shaft of the shift clutch 6. The working power output drive shaft S1 is connected to the working power input shaft through a PTO clutch 44 and is provided with a high-speed working power drive gear 45 and a low-speed working power drive gear 46. The working power output driven shaft S2 is used to connect to the working mechanism and is fitted with a high-speed working power driven gear 47 and a low-speed working power driven gear 48 that respectively mesh with the high-speed working power drive gear 45 and the low-speed working power drive gear 46, as well as a meshing sleeve 49 for selectively connecting the working power output driven shaft S2 to the high-speed working power driven gear 47 or the low-speed working power driven gear 48. The power from the shift clutch 6 is transmitted to the working power output drive shaft S1 via the working power input shaft and the PTO clutch 44. Both the high-speed working power drive gear 45 and the low-speed working power drive gear 46 rotate with the working power output drive shaft S1. Through the engagement sleeve 49, they connect with the high-speed working power driven gear 47 or the low-speed working power driven gear 48, enabling different speed inputs to the working power output driven shaft S2, thus achieving power output and high / low gear switching to drive the working mechanism. When the engagement sleeve 49 slides to the front end, the high-speed gear engages, and the spline of the engagement sleeve 49 engages with the spline of the high-speed working power driven gear 47. The high-speed working power driven gear 47 is relatively fixed to the working power output driven shaft S2, and the PTO clutch 44 outputs power. The power output of the PTO clutch 44 is transmitted to the driven shaft S2 via the working power output drive shaft S1, the high-speed working power drive gear 45, the high-speed working power driven gear 47, and the engagement sleeve 49. When the engagement sleeve 49 slides to the rear end, the low-speed gear engages, and the spline of the engagement sleeve 49 engages with the spline of the low-speed working power driven gear 48. The low-speed working power driven gear 48 is relatively fixed to the working power output driven shaft S2. The power output of the PTO clutch 44 is transmitted to the working power output driven shaft S2 via the working power output drive shaft S1, the low-speed working power drive gear 46, the low-speed working power driven gear 48, and the engagement sleeve 49. When the engagement sleeve 49 is in the middle position, the power output of the PTO clutch 44 is not transmitted to the working power output driven shaft S2.

[0048] In some implementations, the working power output drive shaft S1 and the working power output driven shaft S2 are arranged in parallel.

[0049] In some embodiments, the front end of the shift clutch 6 is connected to the output shaft of the hydraulic pump 2 via a spline, and the rear end of the shift clutch 6 is connected to the rotating gear at the front end of the PTO clutch 44 via a spline. The rear end of the PTO clutch 44 housing is connected to the working power output drive shaft S1 via a spline. When the PTO clutch 44 is engaged, the rotating gear at the front end of the PTO clutch 44 and the PTO clutch 44 housing form a fixed whole, and the power of the shift clutch 6 is transmitted to the working power output drive shaft S1 through the PTO clutch 44. When the PTO clutch 44 is disengaged, the rotating gear at the front end of the PTO clutch 44 rotates with the shift clutch 6, while the PTO clutch 44 housing and the working power output drive shaft S1 do not rotate, and the power is disconnected.

[0050] In some embodiments, the engagement sleeve 49 is splined to the working power output driven shaft S2 and can slide back and forth on the working power output driven shaft S2. The high-speed working power driven gear 47 and the low-speed working power driven gear 48 are mounted on the working power output driven shaft S2 by bearings and can rotate freely around the working power output driven shaft S2.

[0051] The second aspect of this utility model provides a tractor, which includes the transmission system of any of the above-described embodiments. The tractor's transmission system is a mechanical-hydraulic dual-flow transmission, which splits the power of the engine 4 into mechanical power from the shift clutch 6 and hydraulic power from the hydraulic continuously variable transmission device 1, and transmits them to the first planetary gear mechanism 10 or the second planetary gear mechanism 14 for convergence and output. The vehicle's stepless speed regulation is achieved by adjusting the speed at the output end of the hydraulic continuously variable transmission device 1 and the gear position of the shift clutch 6. Furthermore, this transmission system reduces the number of gear transmission stages, has a simple structure, occupies little space, has low production costs, facilitates vehicle weight reduction, has higher transmission efficiency, effectively reduces labor intensity, and has a clear transmission route.

[0052] In the description of this utility model, it should be understood 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 as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this utility model, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0053] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0054] 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.

[0055] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A transmission system, characterized in that, include: A hydraulic continuously variable transmission (CVT) (1), the input end of which is connected to an engine (4) via transmission; a shift clutch (6), the shift clutch (6) being configured to selectively connect the engine (4) to a high-speed shift drive gear (7) or a low-speed shift drive gear (8); a first planetary gear mechanism (10), the first input end and the second input end of which are respectively connected to the output end of the hydraulic CVT (1) and the high-speed shift drive gear (7); and The second planetary gear mechanism (14) has its first and second input ends connected to the output end of the hydraulic continuously variable transmission (1) and the low-speed shift drive gear (8), respectively. The rotational speeds of the first and second input ends of the first planetary gear mechanism (10) are the same as those of the first and second input ends of the second planetary gear mechanism (14). The output ends of the first planetary gear mechanism (10) and the second planetary gear mechanism (14) are connected to the drive wheel (24).

2. The transmission system according to claim 1, characterized in that, The hydraulic continuously variable transmission (1) includes a hydraulic pump (2) driven by the engine (4) and a hydraulic motor (3) driven by the hydraulic pump (2).

3. The transmission system according to claim 2, characterized in that, The transmission system also includes a sun gear shaft (9), which is configured to be driven synchronously by the hydraulic motor (3); the first planetary gear mechanism (10) includes a first sun gear disposed on the sun gear shaft (9), a first planet carrier (11) with a converging gear, and a first ring gear (12), the converging gear meshing with the high-speed shift drive gear (7); the second planetary gear mechanism (14) includes a second sun gear disposed on the sun gear shaft (9), a second planet carrier (15), and a second ring gear (16), the second ring gear (16) having an external gear meshing with the low-speed shift drive gear (8); the first ring gear (12) and the second planet carrier (15) are connected to the drive wheel (24) as output ends.

4. The transmission system according to claim 3, characterized in that, The first gear ring (12) and the second planetary carrier (15) are connected to each other through a spline sleeve (13), so that the first gear ring (12) is connected to the drive wheel (24) through the spline sleeve (13) and the second planetary carrier (15).

5. The transmission system according to claim 1, characterized in that, The transmission system further includes a travel transmission mechanism for drivingly connecting the output ends of the first planetary gear mechanism (10) and the second planetary gear mechanism (14) to the drive wheel (24). The travel transmission mechanism includes: a reversing drive gear (17), which is drivingly connected to the output ends of the first planetary gear mechanism (10) and the second planetary gear mechanism (14); and a reversing double gear (18), which is disposed on the output shaft of the segment-changing clutch (6). The large gear of (18) meshes with the reversing drive gear (17); the reversing idler gear (19) meshes with the small gear of the reversing double gear (18); the reversing driven gear (20) meshes with the reversing idler gear (19); and the reversing synchronizer (21) is selectively connected to the reversing drive gear (17) or the reversing driven gear (20), the output end of the reversing synchronizer (21) being connected to the drive wheel (24) in a transmission.

6. The transmission system according to claim 5, characterized in that, The walking transmission mechanism further includes: a bevel gear shaft (50), which is arranged parallel to the input shaft of the shift clutch (6), and one end of the bevel gear shaft (50) is connected to the output end of the reversing synchronizer (21); a driving bevel gear (22), which is disposed at the other end of the bevel gear shaft (50); a driven bevel gear (23), which meshes with the driving bevel gear (22); and a third planetary gear mechanism (25). The third sun gear (26) of the third planetary gear mechanism (25) is driven to the output end of the driven bevel gear (23), and the third planet carrier (27) of the third planetary gear mechanism (25) is driven to the left wheel; and the fourth planetary gear mechanism (29) has the fourth sun gear (51) driven to the output end of the driven bevel gear (23), and the fourth planet carrier (52) of the fourth planetary gear mechanism (29) is driven to the right wheel.

7. The transmission system according to claim 6, characterized in that, The transmission system further includes a hydraulic steering device, which includes: a steering drive gear (54) located outside the shift clutch (6); a steering idler gear (30) meshing with the steering drive gear (54); a steering driven gear (31) meshing with the steering idler gear (30); a steering pump (32) whose input end is connected to the steering driven gear (31); a steering motor (33) driven by the steering pump (32); and a hydraulic steering mechanism whose input end is connected to the steering motor (33), and whose output end is connected to the third ring gear (28) of the third planetary gear mechanism (25) and the fourth ring gear (53) of the fourth planetary gear mechanism (29), respectively.

8. The transmission system according to claim 7, characterized in that, The hydraulic steering mechanism includes: a multi-stage hydraulic gear set, the input end of which is connected to the output end of the steering motor (33); a first steering gear (34), which is connected to the output end of the multi-stage hydraulic gear set and meshes with the third gear ring (28); and a second steering gear (35), which is connected to the output end of the multi-stage hydraulic gear set and meshes with the fourth gear ring (53) through a hydraulic idler wheel (36), such that the third gear ring (28) and the fourth gear ring (53) have the same rotation speed and opposite rotation directions.

9. The transmission system according to any one of claims 1-8, characterized in that, The transmission system also includes a working power transmission component, which is connected to the output shaft of the shift clutch (6) and to the working mechanism.

10. A tractor, characterized in that, The tractor includes a transmission system according to any one of claims 1-9.

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