Hmcvt power split transmission system for tractor

Abstract

The utility model relates to tractor gearbox technical field, specifically, relates to a tractor with HMCVT power split transmission system. The system includes power input shaft, and power input shaft transmission connection has variable pump, motor, and the output end transmission connection of motor has first sun gear, and power input shaft installs first gear ring, and first gear ring and first sun gear between installation have first planetary gear, and first planetary gear is connected with first planet carrier, still include auxiliary gearbox input shaft, and auxiliary gearbox input shaft is connected with first planet carrier between advance block clutch, and auxiliary gearbox input shaft installs second sun gear and second gear ring, and second gear ring is rotatably connected with auxiliary gearbox input shaft, and second gear ring is connected with brake, and second gear ring and second sun gear between installation have mutually meshed second planetary gear, third planetary gear, and second planetary gear, third planetary gear install on first planet carrier. The structural scheme of whole transmission is simple and compact, and reduces system cost.

Description

Technical Field

[0001] This utility model relates to the field of tractor gearbox technology, specifically to an HMCVT power split transmission system for tractors. Background Technology

[0002] Tractors, as the core power equipment of modern agricultural production, are widely used in all aspects of tilling, sowing, fertilizing, harvesting, and transportation. Currently, most agricultural tractors in China use manual shift gearboxes. Traditional manual shift gearboxes and even more advanced power shift gearboxes have fixed gear ratios for each gear. To reduce engine fuel consumption and shift shock, existing technology uses the method of increasing the number of gears in the gearbox to buffer the impact of gear changes. However, more and more gears also mean that the gearbox structure becomes more and more complex, and at the same time, power interruption is prone to occur during gear shifts, affecting the vehicle's ability to adapt to various complex working conditions.

[0003] Hydraulic mechanical continuously variable transmission (HMCVT) combines the stepless speed regulation of hydraulic transmission with the high efficiency of mechanical transmission, making it the preferred transmission solution for modern high-end tractors. It can achieve smooth speed changes while ensuring uninterrupted traction, significantly improving work quality and driver comfort.

[0004] Existing foreign technologies are extremely complex and cannot meet the cost-effectiveness requirements of domestic tractors, such as... Figure 3 As shown, the ECCOM series CVT from the German company ZF employs a stepped-shift transmission system with seven wet clutches and three planetary gear sets, while the continuously variable transmission (CVT) uses a variable displacement hydraulic pump and motor, along with a planetary gear set, making the entire system extremely complex and costly. Currently, there is an urgent need in China for tractor transmissions with continuously variable performance and low cost to meet the demands of domestic agricultural machinery and promote the advancement of tractor modernization technology. Utility Model Content

[0005] The purpose of this invention is to provide a power split transmission system for tractors that addresses the above problems. It utilizes two sets of planetary gear sets to achieve continuously variable transmission and power reversal functions, and is simple, compact, and reduces system costs.

[0006] To achieve the above objectives, this utility model discloses an HMCVT power split transmission system for tractors. The system includes a power input shaft, a variable displacement pump connected to the power input shaft, a motor connected to the variable displacement pump, a first sun gear connected to the output end of the motor, a first ring gear mounted on the power input shaft, a first planetary gear mounted between the first ring gear and the first sun gear, and a first planetary carrier connected to the first planetary gear. It also includes a secondary gearbox input shaft, a forward gear clutch connected between the secondary gearbox input shaft and the first planetary carrier, a second sun gear and a second ring gear mounted on the secondary gearbox input shaft, the second ring gear rotatably connected to the secondary gearbox input shaft, a brake connected to the second ring gear, and meshing second and third planetary gears mounted between the second ring gear and the second sun gear. The second and third planetary gears are mounted on the first planetary carrier, and the secondary gearbox input shaft is connected to the travel output shaft.

[0007] In operation, the engine's power is input to the system via the power input shaft. Part of the power is transmitted to the first planetary carrier via the first ring gear and first planetary gears – this is the mechanical power transmission path. The other part of the power is transmitted to the variable displacement pump, which converts the mechanical energy into hydraulic energy and transmits it to the motor. The motor then converts the hydraulic energy back into mechanical energy, which is transmitted to the first planetary carrier via the first sun gear and first planetary gears – this is the hydraulic power transmission path. The two power components are coupled on the first planetary carrier. With a constant input speed, by continuously changing the displacement of the variable displacement pump, the motor speed can be altered, thereby changing the speed of the first planetary carrier and achieving continuously variable transmission (CVT).

[0008] When the forward gear clutch is engaged and the brake is disengaged, power is directly transmitted to the input shaft of the auxiliary gearbox; this is forward gear. When the forward gear clutch is disengaged and the brake is engaged, the second ring gear is locked and its speed is zero. Power is transmitted to the input shaft of the auxiliary gearbox via the second planetary gear set, and the rotational direction of the second sun gear is opposite to that of the second planetary carrier; this is reverse gear.

[0009] The technical solution of this application can realize continuously variable transmission and power reversal functions, and can realize automatic speed change according to changes in load and other factors during operation. Through optimized structural design, the structure of the entire transmission is simple and compact, reducing system cost.

[0010] Preferably, a first-speed drive gear, a second-speed drive gear, a third-speed drive gear, and a fourth-speed drive gear are installed on the input shaft of the auxiliary gearbox. The travel output shaft includes a rear drive output shaft, on which a first-speed driven gear, a second-speed driven gear, a third-speed driven gear, and a fourth-speed driven gear are correspondingly installed. A first-speed and second-speed synchronizer is provided between the first-speed and second-speed driven gears, and a third-speed and fourth-speed synchronizer is provided between the third-speed and fourth-speed driven gears.

[0011] In use, the engagement sleeves of the first and second gear synchronizers and the third and fourth gear synchronizers can slide left and right. When the engagement sleeves of the first and second gear synchronizers slide to the right, the first gear driven gear is connected to the rear drive output shaft, which is the first gear state. When the engagement sleeves of the first and second gear synchronizers slide to the left, the second gear driven gear is connected to the rear drive output shaft, which is the second gear state. When the engagement sleeves of the third and fourth gear synchronizers slide to the right, the third gear driven gear is connected to the rear drive output shaft, which is the third gear state. When the engagement sleeves of the third and fourth gear synchronizers slide to the left, the fourth gear driven gear is connected to the rear drive output shaft, which is the fourth gear state.

[0012] The technical solution of this application can realize the continuously variable transmission function and power reversing function of four forward gears and reverse gears. It can realize automatic speed change according to the changes of load, etc. during operation. Through optimized structural design, the structure of the entire transmission is simple and compact, reducing system cost.

[0013] Preferably, the travel output shaft further includes a front drive output shaft, which is connected to a front drive driven gear via a front drive clutch, and a front drive driving gear that meshes with the front drive driven gear is mounted on the rear drive output shaft.

[0014] When in use, when the front drive clutch is engaged, the rear drive output shaft and drive gear drive the front drive driven gear and front drive output shaft to rotate, thus switching between two-wheel drive and four-wheel drive modes.

[0015] Preferably, a variable pump drive gear is mounted on the power input shaft, and a variable pump driven gear is mounted on the input end of the variable pump.

[0016] In use, the power input shaft and the variable pump drive gear drive the variable pump driven gear and the variable pump input to rotate. The structure is compact and easy to use.

[0017] Preferably, a motor drive gear is installed at the output end of the motor, and a corresponding motor driven gear is installed on the first sun gear.

[0018] In use, the motor and the motor drive gear drive the motor driven gear and the first sun gear to rotate. The structure is compact and easy to use.

[0019] Preferably, the gear ratio between the second gear ring and the second sun gear is 1.5-2.5.

[0020] When in use, the forward and reverse gear ratios can be the same or close, improving comfort.

[0021] Preferably, a hydraulic pump is connected to the end of the power input shaft.

[0022] When in use, the hydraulic pump is used for tasks such as lifting plows, and it is easy to use.

[0023] Preferably, a PTO drive gear is mounted on the power input shaft, and a PTO driven gear that meshes with the PTO drive gear is connected to the power output shaft via a PTO clutch.

[0024] When in use, the PTO clutch C controls the output and cut-off of power from the power take-off shaft, making it easy to use.

[0025] In summary, the beneficial effects of this utility model are as follows: the technical solution of this application can realize continuously variable transmission and power reversal functions, and can realize automatic speed change according to changes in load, etc. during operation. Through optimized structural design, the structure of the entire transmission is simple and compact, reducing system cost. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of an HMCVT power split transmission system for tractors according to this utility model; Figure 2 This utility model relates to a shifting instruction for an HMCVT power split transmission system for tractors; Figure 3 This is a schematic diagram of the structure of a CVT transmission in the background art.

[0027] In the diagram: 1. Power input shaft; 2. Variable pump drive gear; 3. Variable pump driven gear; 4. Variable pump; 5. Motor; 6. Motor drive gear; 7. Motor driven gear; 8. First sun gear; 9. First planet gear; 10. First planet carrier; 11. First ring gear; 12. Second planet carrier; 13. Second ring gear; 14. Second planet gear; 15. Third planet gear; 16. Second sun gear; 17. Secondary gearbox input shaft; 18. Fourth gear drive gear; 19. Third gear drive gear; 20. Second gear drive gear; 21. 1. First gear drive gear; 22. Fourth gear driven gear; 23. Third gear driven gear; 24. Second gear driven gear; 25. First gear driven gear; 26. Third and fourth gear synchronizers; 27. First and second gear synchronizers; 28. Rear drive output shaft; 29. ​​Front drive drive gear; 30. Front drive driven gear; 31. Front drive output shaft; 32. PTO drive gear; 33. PTO driven gear; 34. Power output shaft; 35. Hydraulic pump; B1. Brake; C1. Forward gear clutch; C2. Front drive clutch; C3. PTO clutch. Detailed Implementation

[0028] The specific embodiments of this utility model will be further described in detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this utility model, but are not intended to limit the scope of this utility model.

[0029] 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 technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0030] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" 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 mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0031] like Figure 1As shown, a power split transmission system for tractors (HMCVT) includes a power input shaft 1, a variable pump 4 connected to the power input shaft 1, a motor 5 connected to the variable pump 4, a first sun gear 8 connected to the output end of the motor 5, a first gear ring 11 mounted on the power input shaft 1, a first planet gear 9 mounted between the first gear ring 11 and the first sun gear 8, the first planet gear 9 connected to a first planet carrier 10, and a secondary gearbox input shaft 17. Specifically, the secondary gearbox input shaft 17 is a hollow structure, through which the power input shaft 1 passes. A forward gear clutch C1 is connected between the secondary gearbox input shaft 17 and the first planetary carrier 10. A second sun gear 16 and a second ring gear 13 are mounted on the secondary gearbox input shaft 17. The second ring gear 13 is rotatably connected to the secondary gearbox input shaft 17. A brake B1 is connected to the second ring gear 13. A second planetary gear 14 and a third planetary gear 15 are installed between the second ring gear 13 and the second sun gear 16. A second planetary carrier 12 is connected to the first planetary carrier 10. The second planetary gear 14 and the third planetary gear 15 are mounted on the second planetary carrier 12. The secondary gearbox input shaft 17 is drive-connected to the travel output shaft. In operation, the engine's power is input to the system via the power input shaft 1. Part of the power is transmitted to the first planetary carrier 10 via the first ring gear 11 and the first planetary gear 9 – this is the mechanical power transmission path. The other part of the power is transmitted to the variable pump 4, which converts mechanical energy into hydraulic energy and transmits it to the motor 5. The motor 5 converts hydraulic energy back into mechanical energy, which is then transmitted to the first planetary carrier 10 via the first sun gear 8 and the first planetary gear 9 – this is the hydraulic power transmission path. The two power components are coupled on the first planetary carrier 10. With a constant input speed, by continuously changing the displacement of the variable pump 4, the speed of the motor 5 can be changed, thereby changing the speed of the first planetary carrier 10, achieving continuously variable transmission (CVT). When the forward gear clutch C1 engages and the brake B1 disengages, the power is directly transmitted to the auxiliary gearbox input shaft 17, which is the forward gear position. When the forward gear clutch C1 is disengaged and the brake B1 is engaged, the second ring gear 13 is locked and its speed is zero. Power is transmitted to the input shaft 17 of the auxiliary gearbox via the second planetary gear set. The rotational direction of the second sun gear 16 is opposite to that of the second planetary carrier 12. At this time, it is in reverse gear.

[0032] The technical solution of this application can realize continuously variable transmission and power reversal functions, and can realize automatic speed change according to changes in load and other factors during operation. Through optimized structural design, the structure of the entire transmission is simple and compact, reducing system cost.

[0033] Specifically, a variable pump drive gear 2 is mounted on the power input shaft 1, and a variable pump driven gear 3 is correspondingly mounted on the input end of the variable pump 4. In operation, the power input shaft 1 and the variable pump drive gear 2 drive the variable pump driven gear 3 and the input of the variable pump 4, resulting in a compact structure and ease of use. A motor drive gear 6 is mounted on the output end of the motor 5, and a motor driven gear 7 is correspondingly mounted on the first sun gear 8. In operation, the motor 5 and the motor drive gear 6 drive the motor driven gear 7 and the first sun gear 8, resulting in a compact structure and ease of use. The gear ratio between the second gear ring 13 and the second sun gear 16 is 1.5-2.5. Specifically, it can be 1.5, 2.0, or 2.5. In operation, the forward and reverse gear ratios can be the same or close, improving comfort.

[0034] Specifically, a hydraulic pump 35 is connected to the end of the power input shaft 1. In use, the hydraulic pump 35 is used for tasks such as plow lifting, and is easy to operate. A PTO drive gear 32 is mounted on the power input shaft 1, and a PTO driven gear 33, which meshes with the PTO drive gear 32, is connected to the power output shaft 34 via a PTO clutch C3. In use, the PTO clutch C3 controls the power output and cutoff of the power output shaft 34, and is easy to operate.

[0035] like Figure 1 , Figure 2 As shown, a first-speed drive gear 21, a second-speed drive gear 20, a third-speed drive gear 19, and a fourth-speed drive gear 18 are mounted on the input shaft 17 of the auxiliary gearbox. The drive output shaft includes a rear drive output shaft 28, on which a first-speed driven gear 25, a second-speed driven gear 24, a third-speed driven gear 23, and a fourth-speed driven gear 22 are correspondingly mounted. A first-speed and second-speed synchronizer 27 is provided between the first-speed driven gear 25 and the second-speed driven gear 24, and a third-speed and fourth-speed synchronizer 26 is provided between the third-speed driven gear 23 and the fourth-speed driven gear 22. In use, the engagement sleeves of the first and second gear synchronizers 27 and the third and fourth gear synchronizers 26 can slide left and right. When the engagement sleeve of the first and second gear synchronizers 27 slides to the right, the first gear driven gear 25 is connected to the rear drive output shaft 28, which is the first gear state. When the engagement sleeve of the first and second gear synchronizers 27 slides to the left, the second gear driven gear 24 is connected to the rear drive output shaft 28, which is the second gear state. When the engagement sleeve of the third and fourth gear synchronizers 26 slides to the right, the third gear driven gear 23 is connected to the rear drive output shaft 28, which is the third gear state. When the engagement sleeve of the third and fourth gear synchronizers 26 slides to the left, the fourth gear driven gear 22 is connected to the rear drive output shaft 28, which is the fourth gear state.

[0036] The technical solution of this application can realize continuously variable transmission (CVT) with four forward gears and reverse gear, as well as power reversing function. It enables automatic gear shifting during operation based on changes in load, etc. Through optimized structural design, the entire transmission structure is simple and compact, reducing system cost. By controlling the disengagement and engagement of the forward gear clutch C1 and brake B1, the vehicle can achieve power reversing function in four gears.

[0037] Specifically, the drive output shaft also includes a front drive output shaft 31, which is connected to a front drive driven gear 30 via a front drive clutch C2. A front drive driving gear 29, which meshes with the front drive driven gear 30, is mounted on the rear drive output shaft 28. In use, when the front drive clutch C2 is engaged, the rear drive output shaft 28 and the front drive driving gear 29 drive the front drive driven gear 30 and the front drive output shaft 31 to rotate, thereby switching between two-wheel drive and four-wheel drive modes.

[0038] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present utility model, and these improvements and substitutions should also be considered within the protection scope of the present utility model.

Claims

1. A power split transmission system for tractors (HMCVT), comprising a power input shaft (1), a variable displacement pump (4) connected to the power input shaft (1), and a motor (5) connected to the variable displacement pump (4), characterized in that, The output end of the motor (5) is connected to a first sun gear (8). A first gear ring (11) is mounted on the power input shaft (1). A first planet gear (9) is mounted between the first gear ring (11) and the first sun gear (8). The first planet gear (9) is connected to a first planet carrier (10). The motor also includes a secondary gearbox input shaft (17). A forward gear clutch (C1) is connected between the secondary gearbox input shaft (17) and the first planet carrier (10). A second sun gear (16) and a second gear ring (13) are mounted on the secondary gearbox input shaft (17). The second gear ring (13) is rotatably connected to the secondary gearbox input shaft (17). A brake (B1) is connected to the second gear ring (13). A second planet gear (14) and a third planet gear (15) are installed between the second gear ring (13) and the second sun gear (16). The second planet gear (14) and the third planet gear (15) are mounted on the first planet carrier (10). The secondary gearbox input shaft (17) is connected to the travel output shaft.

2. The HMCVT power split drive system for tractors as described in claim 1, characterized in that, The auxiliary gearbox input shaft (17) is equipped with a first gear drive gear (21), a second gear drive gear (20), a third gear drive gear (19) and a fourth gear drive gear (18). The drive output shaft includes a rear drive output shaft (28). The rear drive output shaft (28) is equipped with a first gear driven gear (25), a second gear driven gear (24), a third gear driven gear (23) and a fourth gear driven gear (22). The first gear driven gear (25) and the second gear driven gear (24) are connected by a first and second gear synchronizer (27). The third gear driven gear (23) and the fourth gear driven gear (22) are connected by a third and fourth gear synchronizer (26).

3. The HMCVT power split transmission system for tractors as described in claim 2, characterized in that, The drive output shaft also includes a front drive output shaft (31), which is connected to a front drive driven gear (30) via a front drive clutch (C2), and a front drive driving gear (29) that meshes with the front drive driven gear (30) is mounted on the rear drive output shaft (28).

4. The HMCVT power split drive system for tractors as described in claim 1, characterized in that, A variable pump drive gear (2) is installed on the power input shaft (1), and a variable pump driven gear (3) is installed at the input end of the variable pump (4).

5. The HMCVT power split drive system for tractors as described in claim 1, characterized in that, The output end of the motor (5) is equipped with a motor drive gear (6), and the first sun gear (8) is equipped with a corresponding motor driven gear (7).

6. The HMCVT power split drive system for tractors as described in claim 1, characterized in that, The gear ratio between the second gear ring (13) and the second sun gear (16) is 1.5-2.

5.

7. The HMCVT power split drive system for tractors as described in any one of claims 1 to 6, characterized in that, A hydraulic pump (35) is connected to the end of the power input shaft (1).

8. The HMCVT power split drive system for tractors as described in any one of claims 1 to 6, characterized in that, A PTO drive gear (32) is mounted on the power input shaft (1), and a PTO driven gear (33) that meshes with the PTO drive gear (32) is connected to the power output shaft (34) via a PTO clutch (C3).

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