Continuously variable transmission of ECVT tractor

Abstract

The invention discloses a continuously variable transmission of an ECVT tractor, which comprises an input shaft, a generator, a driving motor, a first clutch, a second clutch, a first sun gear, a plurality of first planet gears, a first gear ring, a first planet carrier, a second sun gear, a plurality of second planet gears, a second gear ring, a second planet carrier and an output gear, the input shaft drives the generator to generate electricity, the driving motor is sleeved on the input shaft, the first sun gear is coaxially and fixedly connected with an output shaft of the driving motor, the first clutch is respectively connected with the input shaft and the second sun gear, and the second clutch is respectively connected with the first planet carrier and the second sun gear. An engine-generator-driving motor electromechanical coupling stepless speed change scheme is adopted, a traditional multi-gear shifting mechanism is omitted, shifting power interruption is avoided, the structure is compact, and the transmission efficiency and reliability are high.

Description

Technical Field

[0001] This invention relates to the field of gearbox technology, and in particular to a continuously variable transmission (CVT) for an ECVT tractor. Background Technology

[0002] Existing tractor transmission systems mainly include stepped transmissions (mechanical shifting, power shifting) and continuously variable transmissions (HST, V-belt mechanical continuously variable transmission, CVT). Among them, CVT technology achieves stepless speed regulation by combining hydrostatic and mechanical transmission, improving work efficiency and driving comfort. However, in high-horsepower tractors, it suffers from insufficient transmission efficiency, low reliability of core components, and limitations on large-scale application. Summary of the Invention

[0003] To address the aforementioned technical problems, the present invention aims to provide a continuously variable transmission (CVT) for an ECVT tractor that can simultaneously improve transmission efficiency and reliability.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A continuously variable transmission (CVT) for an ECVT tractor includes: an input shaft, a generator, a drive motor, a first clutch, a second clutch, a first sun gear, a plurality of first planetary gears, a first ring gear, a first planetary carrier, a second sun gear, a plurality of second planetary gears, a second ring gear, a second planetary carrier, and an output gear. The generator is mounted on the input shaft and drives it to generate electricity. The drive motor is loosely fitted onto the input shaft. The first sun gear is coaxially and fixedly connected to the output shaft of the drive motor and is driven to rotate by the drive motor. The first sun gear externally meshes with the plurality of first planetary gears, and the plurality of first planetary gears internally mesh with the first ring gear. The first ring gear is fixedly mounted on the gearbox housing. The first planetary gears are mounted at one end of the first planetary carrier via bearings. The other end of the first planetary carrier is coaxially fixedly connected to or integrally formed with the second ring gear. Several second planetary gears mesh internally with the second ring gear, and several second planetary gears mesh externally with the sun gear. The sun gear is loosely fitted on the input shaft. The second planetary gears are mounted on one end of the second planetary carrier through bearings. The other end of the second planetary carrier is coaxially fixedly connected to or integrally formed with the output gear. Power is output through the output gear. The first clutch connects the input shaft and the second sun gear respectively. The engagement and disengagement of the input shaft and the second sun gear are achieved through the engagement and disengagement of the friction plates in the first clutch. The second clutch connects the first planetary carrier and the second sun gear respectively. The engagement and disengagement of the first planetary carrier and the second sun gear are achieved through the engagement and disengagement of the friction plates in the second clutch.

[0006] In some embodiments, the first clutch includes a first inner friction plate and a first outer friction plate arranged alternately. The inner side of the first inner friction plate is splinedly connected to the inner hub of the first clutch, and the outer side of the first inner friction plate is splinedly connected to the outer hub of the first clutch. The inner hub of the first clutch is coaxially fixedly connected to the input shaft or integrally formed, and the outer hub of the first clutch is coaxially fixedly connected to the second sun gear or integrally formed.

[0007] In some embodiments, the second clutch includes a second inner friction plate and a second outer friction plate arranged in an alternating manner, the second inner friction plate...

[0008] The inner side of the second inner friction plate is splinedly connected to the inner hub of the second clutch, the outer side of the second inner friction plate is splinedly connected to the outer hub of the second clutch, the inner hub of the second clutch is coaxially fixedly connected to the second sun gear or integrally formed, and the outer hub of the second clutch is coaxially fixedly connected to the first planetary carrier or integrally formed.

[0009] In some embodiments, the inner hub of the second clutch is coaxially fixedly connected to or integrally formed with the outer hub of the first clutch.

[0010] In some embodiments, the system further includes a first gear, a second gear, a third gear, a first drive shaft, and a high / low gear synchronizer. The first gear is loosely fitted on the input shaft and is coaxially and fixedly connected to the output gear. The second and third gears are loosely fitted on the first drive shaft, which is driven by the rear axle input shaft. The second gear is meshed with the output gear, and the third gear is meshed with the second gear. The high / low gear synchronizer is disposed between the second and third gears and is circumferentially fixedly connected to the first drive shaft for synchronous rotation. The high / low gear synchronizer can engage or disengage with the second or third gear.

[0011] In some embodiments, the system further includes a front axle clutch, a front drive output shaft, a front drive first transmission gear, a front drive second transmission gear, and a front drive third transmission gear. The front drive first transmission gear rotates synchronously and circumferentially fixedly with the first transmission shaft. The front drive second transmission gear meshes with the front drive first transmission gear, and the front drive third transmission gear meshes with the front drive second transmission gear. The front drive third transmission gear is loosely fitted on the front drive output shaft. The front axle clutch is connected to both the front drive output shaft and the front drive third transmission gear. The engagement and disengagement of the front drive third transmission gear and the front drive output shaft are controlled by the engagement and disengagement of the friction plates in the front axle clutch.

[0012] In some embodiments, the system further includes a fourth gear, a fifth gear, and a sixth gear. The fourth gear is fixedly connected to the input shaft and rotates synchronously. The fifth gear meshes with the fourth gear for transmission, and the sixth gear meshes with the fifth gear for transmission. The output end of the sixth gear is connected to an oil pump.

[0013] In some embodiments, the fifth and sixth gears are mounted on the gearbox housing via bearings.

[0014] In some embodiments, the system further includes a PTO clutch, a second drive shaft, a PTO output shaft, a seventh gear, an eighth gear, a ninth gear, a tenth gear, and a PTO high / low gear synchronizer. The PTO clutch is connected to the input shaft and the second drive shaft respectively. The engagement and disengagement of the input shaft and the second drive shaft are achieved through the friction plates in the PTO clutch. The seventh gear and the eighth gear are coaxially fixed on the second drive shaft and rotate synchronously. The ninth gear and the tenth gear are coaxially loosely fitted on the PTO output shaft. The ninth gear meshes with the seventh gear and the tenth gear meshes with the eighth gear. The PTO high / low gear synchronizer is circumferentially fixed and rotates synchronously with the PTO output shaft. The PTO high / low gear synchronizer can engage or disengage with the ninth gear or the tenth gear.

[0015] In some embodiments, the output end of the first drive shaft is coaxially connected to the first bevel gear, and the first bevel gear is connected to the rear axle drive.

[0016] The present invention has the following beneficial effects:

[0017] This invention employs an electromechanical coupling continuously variable transmission (CVT) scheme involving an engine, generator, and drive motor, eliminating the traditional multi-gear shifting mechanism and preventing power interruptions during gear shifts. This allows the tractor to operate without shifting shocks throughout the entire process of starting, working, and driving, while maintaining a wide speed range. The flexible combination of a dual clutch and dual planetary gear set enables the engine to operate within its optimal economic speed range for extended periods, improving transmission efficiency. The high coaxiality of the core components, along with excellent machining and assembly processes, ensures high reliability and convenient maintenance. It is suitable for long-term stable operation under harsh conditions in agricultural machinery, and its compact structure and short transmission chain further enhance transmission efficiency. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the continuously variable transmission (CVT) of an ECVT tractor;

[0019] Explanation of reference numerals in the attached figures:

[0020] 1. Input shaft; 2. Generator; 3. Drive motor; 4. First sun gear; 5. First planetary gear; 6. First ring gear; 71. First planetary carrier; 72. Second ring gear; 81. Output gear; 82. First gear; 9. Second sun gear; 10. Second gear; 11. Third gear; 12. Front drive second transmission gear; 13. Front drive third transmission gear; 14. Fourth gear; 15. Fifth gear; 16. Sixth gear; 17. Seventh gear; 18. Eighth gear; 19. Ninth gear; 20. Tenth gear; 21. First bevel gear 22. Second bevel gear; 23. Differential; 24. Brake; 25. Rear axle sun gear shaft; 26. Rear axle planetary gears; 27. Rear axle ring gear; 28. Rear axle planetary carrier and output shaft assembly; 29. ​​Front drive output shaft; 30. PTO output shaft; 31. Second drive shaft; 32. First drive shaft; 33. Second planetary gear; 34. Front drive first drive gear; 35. Oil pump; A. First clutch; B. Second clutch; C. PTO clutch; D. Front axle clutch; E. PTO high / low gear synchronizer; F. Gearbox high / low gear synchronizer. Detailed Implementation

[0021] The embodiments of the present invention will be described in detail below. It should be emphasized that the following description is merely exemplary and is not intended to limit the scope and application of the present invention.

[0022] It should be noted that when a component is referred to as "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as "connected to" another component, it can be directly connected to or indirectly connected to that other component. Furthermore, a connection can be used for fixing, coupling, or communication.

[0023] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0024] Furthermore, 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. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of the present invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0025] An embodiment of the present invention provides a continuously variable transmission (CVT) for an ECVT tractor, comprising: an input shaft 1, a generator 2, a drive motor 3, a first clutch A, a second clutch B, a first sun gear 4, a plurality of first planetary gears 5, a first ring gear 6, a first planetary carrier 71, a second sun gear 9, a plurality of second planetary gears 33, a second ring gear 72, a second planetary carrier, and an output gear 81. The generator 2 is mounted on the input shaft 1, and the input shaft 1 drives the generator 2 to generate electricity. The drive motor 3 is loosely fitted onto the input shaft 1, i.e., the input shaft 1 passes through the hollow shaft of the drive motor 3, but does not drive the drive motor 3. The first sun gear 4 is coaxially and fixedly connected to the output shaft of the drive motor 3, and is driven to rotate by the drive motor 3. The first sun gear 4 externally meshes with the plurality of first planetary gears 5, and the plurality of first planetary gears 5 internally mesh with the first ring gear 6. The first ring gear 6 is fixedly mounted on the gearbox housing. 5. A bearing is installed at one end of the first planetary carrier 71. The other end of the first planetary carrier 71 is coaxially fixedly connected to or integrally formed with the second gear ring 72. A plurality of second planetary gears 33 are internally meshed with the second gear ring 72, and a plurality of second planetary gears 33 are externally meshed with the sun gear. The sun gear is loosely fitted on the input shaft 1. The second planetary gears 33 are installed at one end of the second planetary carrier via bearings. The other end of the second planetary carrier is coaxially fixedly connected to or integrally formed with the output gear 81. Power is output through the output gear 81. The first clutch A connects the input shaft 1 and the second sun gear 9 respectively. The engagement and disengagement of the friction plates in the first clutch A realizes the engagement and disengagement of the input shaft 1 and the second sun gear 9. The second clutch B connects the first planetary carrier 71 and the second sun gear 9 respectively. The engagement and disengagement of the friction plates in the second clutch B realizes the engagement and disengagement of the first planetary carrier 71 and the second sun gear 9.

[0026] In this embodiment of the invention, the drive motor 3 and the input shaft 1 are coupled via a planetary mechanism to achieve continuously variable transmission (CVT). A first clutch A is installed between the input shaft 1 and the second sun gear 9. By controlling the engagement and disengagement of the main clutch, i.e., the first clutch A, the presence or absence of power input to the gearbox can be controlled, thereby controlling the power output of the front drive output shaft 29 and the rear axle planetary carrier and output shaft assembly 28. A second clutch B is installed between the first planetary carrier 71 and the second sun gear 9. In reverse gear, the engine power drives the generator 2 to generate electricity. By controlling the engagement of the reverse clutch, i.e., the second clutch B, the first clutch A is disengaged, causing the motor to reverse, thus achieving reverse power output for the front drive output shaft 29 and the rear axle planetary carrier and output shaft assembly 28.

[0027] This invention employs an electromechanical coupling continuously variable transmission (CVT) scheme involving an engine, generator, and drive motor, eliminating the traditional multi-gear shifting mechanism and preventing power interruptions during gear shifts. This allows the tractor to operate without shifting shocks throughout the entire process of starting, working, and driving, while maintaining a wide speed range. The flexible combination of a dual clutch and dual planetary gear set enables the engine to operate within its optimal economic speed range for extended periods, improving transmission efficiency. The high coaxiality of the core components, along with excellent machining and assembly processes, ensures high reliability and convenient maintenance. It is suitable for long-term stable operation under harsh conditions in agricultural machinery, and its compact structure and short transmission chain further enhance transmission efficiency.

[0028] The first gear ring 6 is fixedly installed on the gearbox housing, which can directly transmit the reaction force of the planetary mechanism to the housing, with strong load-bearing capacity and large torque resistance.

[0029] In this embodiment, the first planetary carrier 71 and the second gear ring 72 are integrally formed as a planetary carrier and gear ring assembly, the second planetary carrier and the output gear 81 are integrally formed as a gear and planetary carrier assembly, and the output gear 81 and the first gear 82 are integrally formed as a double gear.

[0030] The second planetary carrier is integrally formed with the output gear 81 and the first gear 82, integrating the functions of the planetary carrier and the double gear. On the one hand, it receives power input from the planetary mechanism coupling through the planetary carrier section; on the other hand, it meshes with the second gear 10 and the third gear 11 respectively through the double gear, and selects the high and low gears for power output through the high and low gear synchronizer F of the transmission. The above-mentioned integrated structure has a short power transmission path and high rigidity, which significantly improves the load-bearing capacity and reliability of the transmission.

[0031] In this embodiment and some other embodiments, the first clutch A includes an alternating first inner friction plate and a first outer friction plate. The inner side of the first inner friction plate is splinedly connected to the inner hub of the first clutch A, and the outer side of the first inner friction plate is splinedly connected to the outer hub of the first clutch A. The inner hub of the first clutch A is coaxially fixedly connected to the input shaft 1 or integrally formed, and the outer hub of the first clutch A is coaxially fixedly connected to the second sun gear 9 or integrally formed. The second clutch B includes an alternating second inner friction plate and a second outer friction plate. The inner side of the second inner friction plate is splinedly connected to the inner hub of the second clutch B, and the outer side of the second inner friction plate is splinedly connected to the outer hub of the second clutch B. The inner hub of the second clutch B is coaxially fixedly connected to the second sun gear 9 or integrally formed, and the outer hub of the second clutch B is coaxially fixedly connected to the first planetary carrier 71 or integrally formed. The above structure is compact, has good coaxiality, and can shorten the axial dimension.

[0032] In this embodiment and some other embodiments, the inner hub of the second clutch B is coaxially fixedly connected to or integrally formed with the outer hub of the first clutch A. This arrangement can improve transmission efficiency and enhance structural rigidity.

[0033] In this embodiment and some other embodiments, the system also includes a first gear 82, a second gear 10, a third gear 11, a first drive shaft 32, and a high / low gear synchronizer F. The first gear 82 is loosely fitted on the input shaft 1 and is coaxially and fixedly connected to the output gear 81. The second gear 10 and the third gear 11 are loosely fitted on the first drive shaft 32, which is connected to the rear axle input shaft 1. The second gear 10 meshes with the output gear 81, and the third gear 11 meshes with the second gear 10. The high / low gear synchronizer F is positioned between the second gear 10 and the third gear 11 and is circumferentially fixedly connected to the first drive shaft 32, rotating synchronously. The high / low gear synchronizer F can engage or disengage with either the second gear 10 or the third gear 11. The overall transmission mechanism is compact, has high space utilization, high coaxiality, operates smoothly, and does not interfere with the original power transmission of the input shaft.

[0034] In this embodiment and some other embodiments, the system also includes a front axle clutch D, a front drive output shaft 29, a front drive first transmission gear 34, a front drive second transmission gear 12, and a front drive third transmission gear 13. The front drive first transmission gear 34 is circumferentially fixed and rotates synchronously with the first drive shaft 32. The front drive second transmission gear 12 is meshed with the front drive first transmission gear 34, and the front drive third transmission gear 13 is meshed with the front drive second transmission gear 12. The front drive third transmission gear 13 is loosely fitted on the front drive output shaft 29. The front axle clutch D is connected to both the front drive output shaft 29 and the front drive third transmission gear 13. The engagement and disengagement of the front drive third transmission gear 13 and the front drive output shaft 29 are controlled by the engagement and disengagement of the friction plates in the front axle clutch D. In this embodiment, the second transmission gear 12 is an idler gear, and the second transmission gear 12 is mounted on the gearbox housing via bearings. The above-mentioned front drive transmission system has high integration and compact layout, without significantly increasing the axial dimension.

[0035] In this embodiment and some other embodiments, a fourth gear 14, a fifth gear 15, and a sixth gear 16 are also included. The fourth gear 14 is fixedly connected to the input shaft 1 and rotates synchronously. The fifth gear 15 meshes with the fourth gear 14 for transmission, and the sixth gear 16 meshes with the fifth gear 15 for transmission. The output end of the sixth gear 16 is connected to the oil pump 35. In this embodiment, the fifth gear 15 is an idler gear and is mounted on the gearbox housing via bearings. The sixth gear 16 is also mounted on the gearbox housing via bearings. The fourth gear 14 is fixedly connected to the input shaft 1 and rotates synchronously. The oil pump can be driven to work as soon as the engine starts, and the hydraulic system can build up pressure quickly and reliably.

[0036] In this embodiment and some other embodiments, it also includes a PTO clutch C, a second drive shaft 31, a PTO output shaft 30, a seventh gear 17, an eighth gear 18, a ninth gear 19, a tenth gear 20, and a PTO high / low gear synchronizer E. The PTO clutch C is connected to the input shaft 1 and the second drive shaft 31 respectively. The engagement and disengagement of the input shaft 1 and the second drive shaft 31 are achieved through the friction plates in the PTO clutch C. The seventh gear 17 and the eighth gear 18 are coaxially fixed on the second drive shaft 31 and rotate synchronously. The ninth gear 19 and the tenth gear 20 are coaxially loosely fitted on the PTO output shaft 30. The ninth gear 19 is meshed with the seventh gear 17 and the tenth gear 20 is meshed with the eighth gear 18. The PTO high / low gear synchronizer E is circumferentially fixed and rotates synchronously with the PTO output shaft 30. The PTO high / low gear synchronizer E can engage or disengage with the ninth gear 19 or the tenth gear 20. The above settings can independently control the connection and separation of power between input shaft 1 and second transmission shaft 31, realize the independent on / off of PTO power, without affecting the overall vehicle's travel transmission, meet the power requirements of agricultural machinery under different working conditions, and flexibly switch PTO high and low speeds to adapt to the speed requirements of different agricultural machinery.

[0037] In this embodiment and some other embodiments, the output end of the first drive shaft 32 is coaxially connected to the first bevel gear 21, and the first bevel gear 21 is connected to the rear axle drive. In this embodiment, the rear axle includes a second bevel gear 22, a differential 23, a brake 24, a rear axle sun gear shaft 25, a rear axle planetary gears 26, a rear axle ring gear 27, a rear axle planetary carrier, and an output shaft assembly 28. The second bevel gear 22 is fixed on the differential 23 and meshes with the first bevel gear 21. The brake 24 is mounted on the rear axle sun gear shaft 25, and the rear axle sun gear shaft 25 is connected to the differential 23. The rear axle planetary gears 26 are mounted on the rear axle planetary carrier and output shaft assembly 28 through bearings. The rear axle planetary gears 26 mesh with the rear axle sun gear shaft 25. The rear axle ring gear 27 is fixed on the gearbox housing and meshes with the rear axle planetary gears 26.

[0038] To overcome the efficiency and reliability bottlenecks of traditional CVTs, and to optimize fuel economy and adaptability to complex working conditions, this application considers the use of hybrid technology. Traditional hybrid technology is mostly in the conceptual design stage in the field of agricultural machinery and has not yet been commercialized. This embodiment provides an implementable electric continuously variable transmission (ECVT) drive technology with a hybrid architecture. By decoupling engine power generation and motor drive speed from vehicle speed, and combining energy recovery and multi-condition control strategies, the operating efficiency of high-horsepower tractors is improved. In this embodiment, the input shaft 1 is connected to the engine, which is the only power input element of the transmission. The engine power drives three components to perform different functions through the input shaft 1: 1. The input shaft 1 drives the generator 2 to generate electricity, which supplies the drive motor 3 for stepless speed regulation; 2. The input shaft 1 drives the oil pump 35 to establish hydraulic pressure through the fourth gear 14 → fifth gear 15 → sixth gear 16. The hydraulic pressure controls the disengagement and engagement of the various clutches of the transmission and the lubrication of the transmission; 3. When the first clutch (A) is engaged, the input shaft 1 drives the sun gear 9, forming a planetary mechanism coupling with the drive motor 3. In addition, when the PTO clutch C is engaged, the input shaft 1 can also drive the PTO device to operate.

[0039] The power transmission routes of the electrical system and hydraulic system in this embodiment are as follows:

[0040] Power system: Engine → Input shaft 1 → Generator 2. There is no power disconnection device between generator 2 and input shaft 1. When the engine is started, the generator immediately starts generating electricity; the engine starts synchronously and drives the generator to generate electricity, which is immediate, simple in structure, eliminates the need for power disconnection and engagement mechanisms, reduces failure points, and improves the reliability of the power system.

[0041] Hydraulic system: Engine → Input shaft 1 → Fourth gear 14 → Fifth gear 15 → Sixth gear 16 → Oil pump 35. There is no power disconnect device between oil pump 35 and input shaft 1. When the engine is started, the hydraulic system is immediately established; the engine can drive the oil pump to work, and the hydraulic system can instantly build up pressure, with stable oil supply and timely action, meeting the hydraulic requirements of gearbox control and the whole machine.

[0042] The continuously variable transmission (CVT) for forward and backward movement in this embodiment is implemented as follows:

[0043] How to achieve continuously variable transmission (CVT):

[0044] Clutch: First clutch A is engaged, second clutch B is disengaged;

[0045] Power transmission route 1: Engine → Input shaft 1 → First clutch A → Second sun gear 9;

[0046] Power transmission route 2: Engine → Input shaft 1 → Generator 2 → Drive motor 3 → First sun gear 4 → First planet gear 5 → First planet carrier 71 → Second gear ring 72;

[0047] Power 1 and Power 2 converge at the second planetary gear 33, and through the stepless speed regulation of the drive motor 3, the power of the planetary gear 33 to the output gear 81 is continuously variable.

[0048] Reverse gear implementation method:

[0049] Clutch: First clutch A disengages, second clutch B engages. Second sun gear 9, first planetary carrier 71, and second ring gear 72 form a single unit;

[0050] Power transmission route: Engine → Input shaft 1 → Generator 2 → Drive motor 3 → First sun gear 4 → First planet gear 5 → First planet carrier 71 → Second ring gear 72 → Output gear 81;

[0051] Reverse gear is achieved by reversing the drive motor 3, without the engine directly participating.

[0052] PTO power output method:

[0053] Two gears can be achieved based on the gear engagement status of the PTO high / low gear synchronizer E;

[0054] Gear 1: Engine → Input Shaft 1 → PTO Clutch C → Seventh Gear 17 → Ninth Gear 19 → PTO Output Shaft 30;

[0055] Gear 2: Engine → Input Shaft 1 → PTO Clutch C → Eighth Gear 18 → Tenth Gear 20 → PTO Output Shaft 30;

[0056] The PTO output speed is not affected by the continuously variable transmission (CVT). As long as the engine input speed is constant, the PTO output speed will also be constant.

[0057] Front-drive output method:

[0058] Two gears can be achieved depending on the engagement state of the high / low gear synchronizer F in the transmission.

[0059] Gear 1: Continuously variable transmission (refer to the forward continuously variable transmission and reverse gear implementation method) → Output gear 81 → Second gear 10 → First drive shaft 32 → Front drive first drive gear 34 → Front drive second drive gear 12 → Front drive third drive gear 13 → Front drive output shaft 29.

[0060] Gear 2: Continuously variable transmission (refer to the implementation method of forward continuously variable transmission and reverse gear) → Output gear 81 → Third gear 11 → First drive shaft 32 → Front drive first drive gear 34 → Front drive second drive gear 12 → Front drive third drive gear 13 → Front drive output shaft 29.

[0061] Rear axle output method:

[0062] Two gears can be achieved depending on the engagement state of the high and low gear synchronizer F of the gearbox;

[0063] Gear 1: Continuously variable transmission (refer to the forward continuously variable transmission and reverse gear implementation method) → Output gear 81 → Second gear 10 → First drive shaft 32 → First bevel gear 21 → Second bevel gear 22 → Differential 23 → Rear axle sun gear shaft 25 → Rear axle planetary gears 26 → Rear axle planetary carrier and output shaft assembly 28;

[0064] Gear 2: Continuously variable transmission (refer to the forward continuously variable transmission and reverse gear implementation method) → Output gear 81 → Third gear 11 → First drive shaft 32 → First bevel gear 21 → Second bevel gear 22 → Differential 23 → Rear axle sun gear shaft 25 → Rear axle planetary gears 26 → Rear axle planetary carrier and output shaft assembly 28;

[0065] Braking implementation method:

[0066] The first clutch A disengages, the second clutch B disengages, the brake 24 engages, and the rear axle sun gear shaft 25 locks with the gearbox housing, thus achieving the braking function.

[0067] The above description provides a further detailed explanation of the present invention in conjunction with specific / preferred embodiments, and it should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various substitutions or modifications can be made to these described embodiments without departing from the concept of the present invention, and all such substitutions or modifications should be considered within the scope of protection of the present invention. In the description of this specification, the reference to terms such as "an embodiment," "some embodiments," "preferred embodiment," "example," "specific example," or "some examples," etc., indicates that the 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. Moreover, the specific features, structures, materials, or characteristics described can be combined in any suitable manner in one or more embodiments or examples. Without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification and the features of different embodiments or examples. Although the embodiments of the present invention and their advantages have been described in detail, it should be understood that various changes, substitutions, and modifications can be made herein without departing from the scope of protection of the patent application.

Claims

1. A continuously variable transmission (CVT) for an ECVT tractor, characterized in that, include: The gearbox comprises an input shaft (1), a generator (2), a drive motor (3), a first clutch (A), a second clutch (B), a first sun gear (4), several first planetary gears (5), a first ring gear (6), a first planetary carrier (71), a second sun gear (9), several second planetary gears (33), a second ring gear (72), a second planetary carrier, and an output gear (81). The generator (2) is mounted on the input shaft (1), and the input shaft (1) drives the generator (2) to generate electricity. The drive motor (3) is loosely fitted on the input shaft (1). The first sun gear (4) is coaxially and fixedly connected to the output shaft of the drive motor (3), and is driven to rotate by the drive motor (3). The first sun gear (4) meshes externally with several first planetary gears (5), and several first planetary gears (5) mesh internally with the first ring gear (6). The first ring gear (6) is fixedly mounted on the gearbox housing. The first planetary gears (5) are mounted on one end of the first planetary carrier (71) through bearings. The other end of the first planetary carrier (71) is coaxially fixedly connected to the second gear ring (72) or integrally formed. Several second planetary gears (33) are internally meshed with the second gear ring (72), and several second planetary gears (33) are externally meshed with the sun gear. The sun gear is loosely fitted on the input shaft (1). The second planetary gears (33) are installed at one end of the second planetary carrier through bearings. The other end of the second planetary carrier is coaxially fixedly connected to the output gear (81) or integrally formed. Power is output through the output gear (81). The first clutch (A) is connected to the input shaft (1) and the second sun gear (9) respectively. The engagement and disengagement of the friction plates in the first clutch (A) realizes the engagement and disengagement of the input shaft (1) and the second sun gear (9). The second clutch (B) is connected to the first planetary carrier (71) and the second sun gear (9) respectively. The engagement and disengagement of the first planetary carrier (71) and the second sun gear (9) realizes the engagement and disengagement of the first planetary carrier (71) and the second sun gear (9) through the engagement and disengagement of the friction plates in the second clutch (B).

2. The continuously variable transmission (CVT) for an ECVT tractor as described in claim 1, characterized in that, The first clutch (A) includes a first inner friction plate and a first outer friction plate arranged alternately. The inner side of the first inner friction plate is splinedly connected to the inner hub of the first clutch (A), and the outer side of the first inner friction plate is splinedly connected to the outer hub of the first clutch (A). The inner hub of the first clutch (A) is coaxially fixedly connected to the input shaft (1) or integrally formed. The outer hub of the first clutch (A) is coaxially fixedly connected to the second sun gear (9) or integrally formed.

3. The continuously variable transmission (CVT) for an ECVT tractor as described in claim 2, characterized in that, The second clutch (B) includes a second inner friction plate and a second outer friction plate arranged alternately. The inner side of the second inner friction plate is splinedly connected to the inner hub of the second clutch (B), and the outer side of the second inner friction plate is splinedly connected to the outer hub of the second clutch (B). The inner hub of the second clutch (B) is coaxially fixedly connected to the second sun gear (9) or integrally formed. The outer hub of the second clutch (B) is coaxially fixedly connected to the first planetary carrier (71) or integrally formed.

4. The continuously variable transmission (CVT) for an ECVT tractor as described in claim 3, characterized in that, The inner hub of the second clutch (B) is coaxially fixedly connected to the outer hub of the first clutch (A) or is integrally formed.

5. The continuously variable transmission (CVT) for an ECVT tractor as described in claim 1, characterized in that, It also includes a first gear (82), a second gear (10), a third gear (11), a first drive shaft (32), and a high-low gear synchronizer (F). The first gear (82) is loosely fitted on the input shaft (1) and is coaxially and fixedly connected to the output gear (81). The second gear (10) and the third gear (11) are loosely fitted on the first drive shaft (32). The first drive shaft (32) is connected to the rear axle input shaft (1). The second gear (10) is meshed with the output gear (81) and is connected to the third gear (11). The high-low gear synchronizer (F) is set between the second gear (10) and the third gear (11) and is circumferentially fixedly connected to the first drive shaft (32) for synchronous rotation. The high-low gear synchronizer (F) can engage or disengage with the second gear (10) or the third gear (11).

6. The continuously variable transmission (CVT) for an ECVT tractor as described in claim 5, characterized in that, It also includes a front axle clutch (D), a front drive output shaft (29), a front drive first transmission gear (34), a front drive second transmission gear (12), and a front drive third transmission gear (13). The front drive first transmission gear (34) rotates synchronously with the first transmission shaft (32) in a fixed circumferential direction. The front drive second transmission gear (12) meshes with the front drive first transmission gear (34) for transmission. The front drive third transmission gear (13) meshes with the front drive second transmission gear (12) for transmission. The front drive third transmission gear (13) is loosely fitted on the front drive output shaft (29). The front axle clutch (D) is connected to the front drive output shaft (29) and the front drive third transmission gear (13) respectively. The engagement and disengagement of the front drive third transmission gear (13) and the front drive output shaft (29) are controlled by the engagement and disengagement of the friction plates in the front axle clutch (D).

7. The continuously variable transmission (CVT) for an ECVT tractor as described in claim 1, characterized in that, It also includes a fourth gear (14), a fifth gear (15) and a sixth gear (16). The fourth gear (14) is fixedly connected to the input shaft (1) and rotates synchronously. The fifth gear (15) meshes with the fourth gear (14) for transmission. The sixth gear (16) meshes with the fifth gear (15) for transmission. The output end of the sixth gear (16) is connected to the oil pump (35).

8. The continuously variable transmission (CVT) for an ECVT tractor as described in claim 7, characterized in that, The fifth gear (15) and the sixth gear (16) are mounted on the gearbox housing via bearings.

9. The continuously variable transmission (CVT) for an ECVT tractor as described in claim 1, characterized in that, It also includes a PTO clutch (C), a second drive shaft (31), a PTO output shaft (30), a seventh gear (17), an eighth gear (18), a ninth gear (19), a tenth gear (20), and a PTO high / low gear synchronizer (E). The PTO clutch (C) is connected to the input shaft (1) and the second drive shaft (31) respectively. The engagement and disengagement of the input shaft (1) and the second drive shaft (31) are achieved through the friction plates in the PTO clutch (C). The seventh gear (17) and the eighth gear (18) are connected to the input shaft (19) and the second drive shaft (30). 8) The PTO high and low gear synchronizer is fixed on the second transmission shaft (31) and rotates synchronously. The ninth gear (19) and the tenth gear (20) are coaxially loosely fitted on the PTO output shaft (30). The ninth gear (19) meshes with the seventh gear (17) for transmission, and the tenth gear (20) meshes with the eighth gear (18) for transmission. The PTO high and low gear synchronizer (E) rotates synchronously with the PTO output shaft (30) in a circumferential direction. The PTO high and low gear synchronizer (E) can be engaged or disengaged from the ninth gear (19) or the tenth gear (20).

10. The continuously variable transmission (CVT) for an ECVT tractor as described in claim 1, characterized in that, The output end of the first drive shaft (32) is coaxially connected to the first bevel gear (21), and the first bevel gear (21) is connected to the rear axle drive.

Images