Tractor continuously variable transmission

Abstract

The invention discloses a tractor continuously variable transmission which is used for a tractor transmission system and belongs to the technical field of transmissions.The tractor continuously variable transmission comprises a stepped speed change mechanism and a continuously variable speed regulation mechanism, the stepped speed change mechanism and the continuously variable speed regulation mechanism comprise a shaft system, a gear set and a planetary gear mechanism, and the gear set and the planetary gear mechanism are fixedly installed on the shaft system; the wet clutch is fixedly installed on the shaft system and the gear set, the shaft system comprises a first input shaft and a first intermediate shaft parallel to the first input shaft, a second input shaft is coaxially arranged on the first input shaft, the second input shaft and the first intermediate shaft are in meshing transmission through the gear set, and the second input shaft and the planetary gear mechanism are in meshing transmission. According to the transmission system, the stepless speed change function of four stepped sections of the forward gear and the reverse gear can be achieved, stepless automatic speed change can be achieved according to changes of loads and the like in the operation process, through the optimized structural design, the structural scheme of the whole transmission is simple and compact, and the system cost is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of transmissions, and in particular relates to a continuously variable transmission for a tractor. Background Art

[0002] Tractor transmission. Currently, high-end tractors in developed countries such as Europe and the United States almost all use CVT continuously variable transmission, which has a high degree of automation, but is extremely complex in structure, expensive and inconvenient to maintain. Domestic tractors are basically dominated by manual transmission. Manual transmission has the advantages of high power transmission efficiency, low cost and strong reliability. However, tractors equipped with manual transmission have low operating efficiency, high labor intensity, and cannot adapt to the development needs of agricultural automation and intelligence.

[0003] The existing foreign technologies are extremely complex and cannot meet the cost-effectiveness requirements of domestic tractors. For example, the ECCOM series CVT of the German ZF company uses 7 wet clutch systems and 3 planetary gear trains for the step-shift transmission part, and a variable displacement hydraulic pump and motor for the stepless speed regulation part, in conjunction with a planetary gear train, making the entire system extremely complex and costly. At present, China urgently needs tractor continuously variable transmission technology with the performance of foreign products and low cost to meet the needs of domestic agricultural machinery and promote the advancement of tractor modernization technology.

[0004] Patent application number US06798724 discloses a vehicle continuously variable transmission, including a V-belt driven continuously variable transmission and a power transmission separation drive mechanism, the power transmission separation drive mechanism is composed of a combination of a fluid coupling and a planetary gear, and is arranged between the output shaft of the vehicle continuously variable transmission and the V-belt driven continuously variable transmission. This patent still has room for improvement.

[0005] It should be noted that the above introduction to the technical background is only for the convenience of providing a clear and complete description of the technical solutions of the present application and for the convenience of understanding by those skilled in the art. It cannot be considered that the above technical solutions are well known to those skilled in the art simply because they are described in the background technology section of the present application. Summary of the invention

[0006] In view of the problems existing in the prior art, the present invention provides a tractor continuously variable transmission for use in a tractor transmission system. The transmission system can realize a continuously variable speed change function with four stepped sections for forward and reverse gears, and can realize a continuously variable automatic speed change according to changes in load etc. during operation. Through an optimized structural design, the structural scheme of the entire transmission is simple and compact, and the system cost is reduced.

[0007] In order to solve the above technical problems, the present invention specifically provides the following technical solutions: A continuously variable transmission for a tractor includes a step-shifting mechanism and a stepless speed regulating mechanism. The step-shifting mechanism and the stepless speed regulating mechanism include: a shaft system, a gear set fixedly mounted on the shaft system, a planetary gear mechanism, a variable hydraulic pump and a hydraulic motor. Specifically, the step-shifting mechanism includes 6 gear sets, 4 shaft systems and 6 wet clutches; the stepless speed regulating mechanism includes 2 gear sets, 4 shaft systems, 1 planetary gear mechanism, a variable hydraulic pump and a hydraulic motor. A wet clutch fixedly mounted on the shaft system and the gear set includes an active clutch plate group and a driven clutch plate group.

[0008] According to one embodiment of the present invention, the shaft system includes a first input shaft and a first intermediate shaft arranged parallel to the first input shaft, a second input shaft is coaxially arranged on the first input shaft, the second input shaft is meshed with the first intermediate shaft through a gear set, and the second input shaft is meshed with the planetary gear mechanism.

[0009] Since the torque at the output end is amplified many times more than that at the input end, when the power is coupled at the output end, the torque transmitted by the hydraulic part will increase, the hydraulic loss will increase, and the transmission efficiency will decrease. The present invention uses a part of the engine power to be directly input into the planetary gear mechanism through the first input shaft through the gear ring, and the other part of the power is finally input into the planetary gear mechanism through the transmission of the gear and the intermediate shaft, so that the power is coupled at the input side, the power response is faster, the pressure on the hydraulic mechanism is smaller, and the loss of hydraulic power is reduced, and the transmission efficiency becomes higher.

[0010] According to one embodiment of the present invention, the stepless speed regulating mechanism comprises: a first input shaft, a second input shaft, a first intermediate shaft, a second intermediate shaft, a gear 1, a gear 2, a gear 15, a gear 16, a variable hydraulic pump, a hydraulic motor and a planetary gear mechanism, wherein the first input shaft and the second input shaft are coaxially arranged, the first intermediate shaft and the second intermediate shaft are parallel and arranged with a fixed center distance to the first input shaft. The variable hydraulic pump drive shaft is fixedly connected to the second intermediate shaft, and the hydraulic motor output shaft is fixedly connected to the first intermediate shaft. Gear 1 is fixedly mounted on the second input shaft, gear 2 is fixedly mounted on the first intermediate shaft, gear 1 and gear 2 are meshed for transmission, gear 15 is fixedly mounted on the second intermediate shaft, gear 16 is fixedly mounted on the first input shaft, and gear 15 and gear 16 are meshed for transmission. The planetary gear mechanism comprises a sun gear, a planetary gear, a gear ring and a planet carrier, wherein the sun gear is fixedly mounted on the second input shaft, the gear ring is fixedly mounted on the first input shaft, and the planet carrier is fixedly mounted on the first transmission shaft, and the first transmission shaft is coaxial with the first input shaft, the first output shaft and the second input shaft.

[0011] Power is input through the first input shaft, of which part of the power is directly input into the planetary gear system through the ring gear, and the other part of the power is transmitted to gear 15, the second intermediate shaft, the variable hydraulic pump, the hydraulic motor, the first intermediate shaft, gear 2, gear 1, the second input shaft, the sun gear in sequence through gear 16, and then input into the planetary gear system. The two parts of power are coupled through the planetary gear system and finally output to the first transmission shaft through the planetary carrier. Since the variable hydraulic pump can continuously change the displacement of the pump to change the output of the pump flow, the output speed of the hydraulic motor can be continuously and steplessly changed, and finally the speed of the first transmission shaft can be continuously changed, thereby realizing stepless speed change of the output speed.

[0012] According to one embodiment of the present invention, the stepped speed change mechanism includes: a first transmission shaft, a second transmission shaft, a first output shaft, a second output shaft, gear three, gear four, gear five, gear six, gear seven, gear eight, gear nine, gear ten, gear eleven, gear twelve, gear thirteen, an idler gear, gear fourteen, a first clutch, a second clutch, a third clutch, a fourth clutch, a fifth clutch and a sixth clutch, the first transmission shaft and the first output shaft are coaxial and loosely mounted on the first input shaft, and the second transmission shaft and the second output shaft are parallel and arranged at a fixed center distance from the first input shaft.

[0013] The active clutch plate group of the first clutch is fixed on the first transmission shaft, and the driven clutch plate group of the first clutch is fixed on the first output shaft; the active clutch plate group of the second clutch is fixed on the second transmission shaft, and the driven clutch plate group of the second clutch is fixed on gear five; the active clutch plate group of the third clutch is fixed on the second transmission shaft, and the driven clutch plate group of the third clutch is fixed on gear eight; the active clutch plate group of the fourth clutch is fixed on gear ten, and the driven clutch plate group of the fourth clutch is fixed on the first output shaft; the active clutch plate group of the fifth clutch is fixed on the first output shaft, and the driven clutch plate group of the fifth clutch is fixed on gear eleven; the active clutch plate group of the sixth clutch is fixed on the first output shaft, and the driven clutch plate group of the sixth clutch is fixed on gear thirteen.

[0014] Gear 3 is fixed on the first transmission shaft, gear 4 is fixed on the second transmission shaft, gear 3 and gear 4 are meshed for transmission; gear 5 is loosely sleeved on the second transmission shaft, gear 6 is fixed on the first output shaft, gear 5 and gear 6 are meshed for transmission; gear 8 is loosely sleeved on the second transmission shaft, gear 7 is fixed on the first output shaft, gear 7 and gear 8 are meshed for transmission; gear 9 is fixed on the second transmission shaft, gear 10 is loosely sleeved on the first output shaft, gear 9 and gear 10 are meshed for transmission; gear 12 is fixed on the second output shaft, gear 11 is loosely sleeved on the first output shaft, gear 11 and gear 12 are meshed for transmission. Gear 14 is fixed on the second output shaft, gear 13 is loosely sleeved on the first output shaft, an idler is installed between gear 13 and gear 14, and the idler is meshed with gear 13 and gear 14 respectively for transmission.

[0015] When the first clutch is engaged, the power is directly transmitted to the first output shaft through the first transmission shaft to achieve one gear; when the second clutch is engaged, the power is transmitted to gear three, gear four, the second transmission shaft, the second clutch, gear five, and gear six in sequence through the first transmission shaft, and is output through the first output shaft to achieve the second gear; when the third clutch is engaged, the power is transmitted to gear three, gear four, the second transmission shaft, the third clutch, gear eight, and gear seven in sequence through the first transmission shaft, and is output through the first output shaft to achieve the third gear; when the fourth clutch is engaged, the power is transmitted to gear three, gear four, the second transmission shaft, gear nine, gear ten, and the fourth clutch in sequence through the first transmission shaft, and is output through the first output shaft to achieve the fourth gear; when the fifth clutch is engaged, the power on the first output shaft is transmitted to the fifth clutch, gear eleven, gear twelve, and the second output shaft in sequence to achieve forward gear power output; when the sixth clutch is engaged, the power on the first output shaft is transmitted to the sixth clutch, gear thirteen, idler gear, gear fourteen, and the second output shaft in sequence to achieve reverse gear power output.

[0016] The power output shaft of the continuously variable speed regulating mechanism of the continuously variable transmission system is the first transmission shaft, which is also the power input shaft of the stepped speed change mechanism. The power of the entire transmission system is input through the first input shaft, and then through the speed change of the continuously variable speed change mechanism, and then through the speed change or direction switching of the stepped speed change mechanism, and finally the power is output through the second output shaft to the front and rear axles of the tractor to drive the vehicle.

[0017] The wet clutch in the system is connected and separated by an electronically controlled hydraulic system, thereby realizing the power shifting with stepped speed; the change of the variable pump displacement is realized by switching the pump displacement through a servo motor or an electronically controlled hydraulic system, thereby realizing stepless speed change. During operation, the continuously variable transmission mechanism realizes the continuous variable speed ratio between adjacent stepped gears, thereby realizing the continuous stepless adjustment of the speed ratio in the entire operating speed change area, so that the engine can work in the optimal speed and power area to meet the needs of real-time load changes, and at the same time can reduce the loss of gears due to meshing friction and increase the service life of gears. In addition, when the continuously variable speed regulating mechanism fails, it will not affect the operation of the stepped speed changing mechanism, and the transmission can still rely on the stepped speed changing mechanism for stable power output.

[0018] According to an embodiment of the present invention, the gears in the gear set are spoke-type gears, and the spoke-type gears have fan blade structures between adjacent spokes.

[0019] When the transmission is working, high temperature will be generated due to the rotational friction and meshing between gears, especially when the clutch is engaged and disconnected, the temperature rises sharply, and it is usually cooled by adding oil. Since the gears are completely immersed in the oil, the internal gears need to overcome a large oil resistance when rotating. The design of adding a fan-blade structure between the spoke-type gears and the adjacent spokes is convenient for maintenance and installation, and can reduce the oil resistance that needs to be overcome when the gears are running, and increase the transmission efficiency. In addition, the fan-blade structure between the adjacent spokes can drive the oil when rotating, causing the oil to flow faster toward the axis of the gear, which can reduce the vibration of the gear transmission mechanism. At the same time, the oil can pass through the through holes on the spoke-type gears. The through holes between the gears make the flow exchange of the oil in the transmission more sufficient, and the heat generated when the gears are running can be transferred to the oil faster, and it can play a certain effect in reducing noise.

[0020] Compared with the prior art, the present invention has the following beneficial effects: The transmission system provided by the present invention can realize the stepless speed change function of 4 stepped sections for forward and reverse gears. The whole process is fully automatically controlled, and stepless automatic speed change can be realized according to the change of load etc. during operation. At the same time, power coupling is adopted on the input side of the transmission, and the step-shifting part is realized by fixed-axis gear combined with clutch. Through the optimized structural design, the structural scheme of the whole transmission is simple and compact, and the system cost is reduced. In addition, the design of the spoke-type gear and the fan blade structure between adjacent spokes can increase the transmission efficiency and reduce the vibration of the gear transmission mechanism. The through holes between the gears make the flow exchange of the oil in the transmission more sufficient, and the heat generated by the operation of the gears can be transferred to the oil more quickly. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the implementation methods of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the implementation methods or the description of the prior art. Obviously, the drawings in the following description are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0022] Figure 1 It is a schematic diagram of the arrangement of the continuously variable transmission of the present invention; Figure 2 It is a schematic diagram of the arrangement of the stepless speed regulating mechanism of the present invention; Figure 3 It is a schematic diagram of the arrangement of the step-variable speed change mechanism of the present invention; Figure 4 It is a schematic diagram of the gear scheme of the present invention; Figure 5 It is a schematic diagram of arrangement scheme 2 of the continuously variable transmission of the present invention; Figure 6It is a schematic diagram of arrangement scheme 3 of the continuously variable transmission of the present invention.

[0023] Reference numerals: 10-variable hydraulic pump; 11-generator; 20-hydraulic motor; 21-drive motor; 110-first input shaft; 120-second input shaft; 130-first intermediate shaft; 140-first transmission shaft; 150-second transmission shaft; 160-first output shaft; 170-second output shaft; 180-second intermediate shaft; 200-planet carrier P1; 201-gear 1; 202-gear 2; 203-sun gear; 204-planetary gear; 205-ring gear; 206-gear 3; 207-gear 4; 208- Gear five; 209-Gear six; 210-Gear seven; 211-Gear eight; 212-Gear nine; 213-Gear ten; 214-Gear eleven; 215-Gear twelve; 216-Gear thirteen; 217-Idler; 218-Gear fourteen; 219-Gear fifteen; 220-Gear sixteen; 301-First clutch; 302-Second clutch; 303-Third clutch; 304-Fourth clutch; 305-Fifth clutch; 306-Sixth clutch; 40-Drive belt; 41-Drive bevel wheel; 42-Driven bevel wheel. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] The following first describes the concepts involved in the present application in conjunction with the accompanying drawings. It should be noted that the following description of each concept is only to make the content of the present application easier to understand, and does not limit the scope of protection of the present application; at the same time, the embodiments and features in the embodiments of the present application can be combined with each other in the absence of conflict. The present application will be described in detail with reference to the accompanying drawings and in conjunction with the embodiments.

[0026] Embodiment 1 See attached Figure 1-Figure 4As shown, a continuously variable transmission for a tractor includes a step-shifting mechanism and a stepless speed regulating mechanism, wherein the step-shifting mechanism and the stepless speed regulating mechanism include: a shaft system, a gear set fixedly mounted on the shaft system, a planetary gear mechanism, a variable hydraulic pump 10 and a hydraulic motor 20. Specifically, the step-shifting mechanism includes 6 gear sets, 4 shaft systems and 6 wet clutches; the stepless speed regulating mechanism includes 2 gear sets, 4 shaft systems, 1 planetary gear mechanism, a variable hydraulic pump 10 and a hydraulic motor 20. A wet clutch fixedly mounted on the shaft system and the gear set includes an active clutch plate group and a driven clutch plate group.

[0027] The stepless speed regulating mechanism comprises: a first input shaft 110, a second input shaft 120, a first intermediate shaft 130, a second intermediate shaft 180, a gear 1 201, a gear 2 202, a gear 15 219, a gear 16 220, a variable hydraulic pump 10, a hydraulic motor 20 and a planetary gear mechanism. The first input shaft 110 and the second input shaft 120 are coaxially arranged, the first intermediate shaft 130 and the second intermediate shaft 180 are parallel and arranged with a fixed center distance to the first input shaft 110. The drive shaft of the variable hydraulic pump 10 is fixedly connected with the second intermediate shaft 180, and the output shaft of the hydraulic motor 20 is fixedly connected with the first intermediate shaft 130. The gear 1 201 is fixedly mounted on the second input shaft 120, the gear 2 202 is fixedly mounted on the first intermediate shaft 130, the gear 1 201 and the gear 2 202 are meshed for transmission, the gear 15 219 is fixedly mounted on the second intermediate shaft 180, the gear 16 220 is fixedly mounted on the first input shaft 110, and the gear 15 219 and the gear 16 220 are meshed for transmission. The planetary gear mechanism includes a sun gear 203 , planetary gears 204 , a ring gear 205 and a planet carrier 200 . The sun gear 203 is fixedly mounted on the second input shaft 120 , the ring gear 205 is fixedly mounted on the first input shaft 110 , and the planet carrier 200 is fixedly mounted on the first transmission shaft 140 .

[0028] The power is input through the first input shaft 110, of which a part of the power is directly input into the planetary gear system through the ring gear 205, and the other part of the power is transmitted to the gear 15 219, the second intermediate shaft 180, the variable hydraulic pump 10, the hydraulic motor 20, the first intermediate shaft 130, the gear 2 202, the gear 1 201, the second input shaft 120, the sun gear 203 in sequence through the gear 16 220, and input into the planetary gear system. The two parts of the power are coupled through the planetary gear system, and finally the power is output to the first transmission shaft 140 through the planetary carrier 200; since the variable hydraulic pump 10 can continuously change the displacement of the pump to change the output of the pump flow, the output speed of the hydraulic motor 20 can be continuously and steplessly changed, and finally the speed of the first transmission shaft 140 can be continuously changed, so as to realize the stepless speed change of the output speed.

[0029] The stepped speed change mechanism includes: a first transmission shaft 140, a second transmission shaft 150, a first output shaft 160, a second output shaft 170, a gear three 206, a gear four 207, a gear five 208, a gear six 209, a gear seven 210, a gear eight 211, a gear nine 212, a gear ten 213, a gear eleven 214, a gear twelve 215, a gear thirteen 216, an idler gear 217, a gear fourteen 218, a first clutch 301, a second clutch 302, a third clutch 303, a fourth clutch 304, a fifth clutch 305 and a sixth clutch 306. The first transmission shaft 140 and the first output shaft 160 are coaxial and loosely mounted on the first input shaft 110. The second transmission shaft 150 and the second output shaft 170 are parallel and arranged with a fixed center distance from the first input shaft 110.

[0030] The active clutch plate group of the first clutch 301 is fixed on the first transmission shaft 140, and the driven clutch plate group of the first clutch 301 is fixed on the first output shaft 160; the active clutch plate group of the second clutch 302 is fixed on the second transmission shaft 150, and the driven clutch plate group of the second clutch 302 is fixed on the gear five 208; the active clutch plate group of the third clutch 303 is fixed on the second transmission shaft 150, and the driven clutch plate group of the third clutch 303 is fixed on the gear eight 211; the active clutch plate group of the fourth clutch 304 is fixed on the gear ten 213, and the driven clutch plate group of the fourth clutch 304 is fixed on the first output shaft 160; the active clutch plate group of the fifth clutch 305 is fixed on the first output shaft 160, and the driven clutch plate group of the fifth clutch 305 is fixed on the gear eleven 214; the active clutch plate group of the sixth clutch 306 is fixed on the first output shaft 160, and the driven clutch plate group of the sixth clutch 306 is fixed on the gear thirteen 216.

[0031] Gear three 206 is fixed on the first transmission shaft 140, gear four 207 is fixed on the second transmission shaft 150, and gear three 206 and gear four 207 are meshed for transmission; gear five 208 is loosely sleeved on the second transmission shaft 150, gear six 209 is fixed on the first output shaft 160, and gear five 208 and gear six 209 are meshed for transmission; gear eight 211 is loosely sleeved on the second transmission shaft 150, gear seven 210 is fixed on the first output shaft 160, and gear seven 210 and gear eight 211 are meshed for transmission; gear nine 212 is fixed on the second transmission shaft 150, gear ten 213 is loosely sleeved on the first output shaft 160, and gear nine 212 and gear ten 213 are meshed for transmission; gear twelve 215 is fixed on the second output shaft 170, gear eleven 214 is loosely sleeved on the first output shaft 160, and gear eleven 214 and gear twelve 215 are meshed for transmission. Gear 14 218 is fixed on the second output shaft 170, gear 13 216 is loosely mounted on the first output shaft 160, and idler gear 217 is installed between gear 13 216 and gear 14 218. Idler gear 217 is meshed with gear 13 216 and gear 14 218 for transmission.

[0032] When the first clutch 301 is engaged, the power is directly transmitted to the first output shaft 160 through the first transmission shaft 140 to achieve a gear position; when the second clutch 302 is engaged, the power is sequentially transmitted to the gear three 206, the gear four 207, the second transmission shaft 150, the second clutch 302, the gear five 208, and the gear six 209 through the first transmission shaft 140, and is output through the first output shaft 160 to achieve a second gear position; when the third clutch 303 is engaged, the power is sequentially transmitted to the gear three 206, the gear four 207, the second transmission shaft 150, the third clutch 303, the gear eight 211, and the gear seven 210 through the first transmission shaft 140, and is output through the first output shaft 160 to achieve a third gear position; when the fourth clutch 302 is engaged, the power is sequentially transmitted to the gear three 206, the gear four 207, the second transmission shaft 150, the third clutch 303, the gear eight 211, and the gear seven 210 through the first transmission shaft 140, and is output through the first output shaft 160 to achieve a third gear position; When the fifth clutch 305 is engaged, the power on the first output shaft 160 is transmitted to the fifth clutch 305, gear 11 214, gear 12 215 and the second output shaft 170 in sequence to realize the forward gear power output; when the sixth clutch 306 is engaged, the power on the first output shaft 160 is transmitted to the sixth clutch 306, gear 13 216, idler 217, gear 14 218 and the second output shaft 170 in sequence to realize the reverse gear power output.

[0033] The power output shaft of the continuously variable speed regulating mechanism of the continuously variable transmission system is the first transmission shaft 140, which is also the power input shaft of the stepped speed change mechanism. The power of the entire transmission system is input through the first input shaft 110, and is shifted by the continuously variable speed change mechanism, and then shifted or switched in direction by the stepped speed change mechanism, and finally the power is output to the front and rear axles of the tractor through the second output shaft 170 to drive the vehicle.

[0034] The wet clutch in the system is connected and separated by an electronically controlled hydraulic system, thereby realizing the power shifting with stepped speed; the change of the variable pump displacement is realized by switching the pump displacement through a servo motor or an electronically controlled hydraulic system, thereby realizing stepless speed change. During operation, the continuously variable speed mechanism realizes the continuous change of the speed ratio between adjacent stepped gears, thereby realizing the continuous stepless adjustment of the speed ratio in the entire operation speed change area, so that the engine can work in the optimal speed and power area to meet the needs of real-time load changes. In addition, when the continuously variable speed mechanism fails, it will not affect the operation of the stepped speed mechanism, and the transmission can still rely on the stepped speed mechanism for stable power output.

[0035] The gears in the gear set are spoke-type gears, and the spoke-type gears have fan blade structures between adjacent spokes.

[0036] When the transmission is working, high temperature will be generated due to the rotational friction and meshing between gears, especially when the clutch is engaged and disconnected, the temperature rises sharply, and it is usually cooled by adding oil. Since the gears are completely immersed in the oil, the internal gears need to overcome a large oil resistance when rotating. The design of adding a fan-blade structure between the spoke-type gears and the adjacent spokes is convenient for maintenance and installation, and can reduce the oil resistance that needs to be overcome when the gears are running, and increase the transmission efficiency. In addition, the fan-blade structure between the adjacent spokes can drive the oil when rotating, causing the oil to flow faster toward the axis of the gear, which can reduce the vibration of the gear transmission mechanism. At the same time, the oil can pass through the through holes on the spoke-type gears. The through holes between the gears make the flow exchange of the oil in the transmission more sufficient, and the heat generated when the gears are running can be transferred to the oil faster, and it can play a certain effect in reducing noise.

[0037] Embodiment 2 See attached Figure 5 As shown, another mode of the continuously variable transmission system of the present invention is to replace the variable hydraulic pump 10 in Example 1 with a generator 11, and replace the hydraulic motor 20 in Example 1 with a drive motor 21. By continuously changing the rotation speed of the generator 11, the rotation speed of the engine connected to the first input shaft 110 is continuously changed, thereby realizing continuously variable transmission, and the transmission response is faster, the cost is lower, and the maintenance is convenient and simple.

[0038] Embodiment 3 See attached Figure 6As shown, another mode of the continuously variable transmission system of the present invention, compared with the scheme of embodiment 1, a mechanical continuously variable transmission mechanism is used to replace the continuously variable transmission mechanism composed of the variable hydraulic pump 10 and the hydraulic motor 20, and the mechanical continuously variable transmission mechanism includes: a driving bevel wheel 41, a driven bevel wheel 42, and a transmission belt 40, wherein the driving bevel wheel 41 is fixedly mounted on the first input shaft 110, the driven bevel wheel 42 is fixedly mounted on the second input shaft 120, the transmission belt 40 is respectively mounted in the driving and driven bevel wheels, and the gear 2 202 is fixedly mounted on the first intermediate shaft 130, and the gear 2 202 is meshed with the gear 1 201 through the idler wheel 217, so that the power transmitted by the mechanical continuously variable transmission mechanism is input to the sun gear 203 of the planetary gear train, and the mechanical continuously variable transmission mechanism composed of the bevel wheel and the transmission belt 40 can realize continuous change of the transmission ratio by changing the meshing radius of the bevel wheel and the transmission belt 40, so that the continuously variable transmission function can also be realized through this implementation scheme. This implementation scheme has high structural strength, low failure rate, and higher transmission ratio.

[0039] The embodiments and / or implementation methods described above are only used to illustrate the preferred embodiments and / or implementation methods for realizing the technology of the present invention, and are not intended to limit the implementation methods of the technology of the present invention in any form. Any technical personnel in this field may make slight changes or modifications to other equivalent embodiments without departing from the scope of the technical means disclosed in the content of the present invention, but they should still be regarded as technologies or embodiments that are essentially the same as the present invention. This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and its core ideas of this application. The above is only the preferred implementation method of this application. It should be pointed out that due to the limitations of textual expression and the objective existence of infinite specific structures, ordinary technicians in this technical field can make several improvements, modifications or changes without departing from the principles of this application, and can also combine the above technical features in an appropriate manner; these improvements, modifications, changes or combinations, or the direct application of the concept and technical solution of the invention to other occasions without improvement, should be regarded as the scope of protection of this application.

Claims

1. A continuously variable transmission for a tractor, comprising a stepped speed change mechanism and a stepless speed regulating mechanism, wherein the stepped speed change mechanism and the stepless speed regulating mechanism comprise: A shaft system, a gear set and a planetary gear mechanism fixedly mounted on the shaft system, and a wet clutch fixedly mounted on the shaft system and the gear set. The invention is characterized in that: the shaft system comprises a first input shaft (110) and a first intermediate shaft (130) arranged in parallel with the first input shaft (110); a second input shaft (120) is coaxially arranged on the first input shaft (110); the second input shaft (120) and the first intermediate shaft (130) are meshed and driven via a gear set; and the second input shaft (120) is meshed and driven with the planetary gear mechanism.

2. A tractor continuously variable transmission according to claim 1, characterized in that: The planetary gear mechanism comprises a sun gear (203), a ring gear (205) and a planet carrier (200); the sun gear (203) is fixedly mounted on the second input shaft (120), the ring gear (205) is fixedly mounted on the first input shaft (110), and the planet carrier (200) is fixedly mounted on the first transmission shaft (140).

3. A continuously variable transmission for tractors according to claim 1, characterized in that: The shaft system further comprises a second intermediate shaft (180), wherein the second intermediate shaft (180) is parallel to the first intermediate shaft (130), and the second intermediate shaft (180) and the first input shaft (110) are arranged at a fixed center distance.

4. A continuously variable transmission for tractors according to claim 3, characterized in that: The second intermediate shaft (180) is fixedly connected to a drive shaft of a variable hydraulic pump (10), and the first intermediate shaft (130) is fixedly connected to an output shaft of a hydraulic motor (20).

5. A continuously variable transmission for tractors according to claim 3, characterized in that: A gear 1 (201) is fixedly mounted on the second input shaft (120), a gear 2 (202) is fixedly mounted on the first intermediate shaft (130), the gear 1 (201) and the gear 2 (202) are meshed for transmission, a gear 15 (219) is fixedly mounted on the second intermediate shaft (180), a gear 16 (220) is fixedly mounted on the first input shaft (110), the gear 15 (219) and the gear 16 (220) are meshed for transmission.

6. A continuously variable transmission for tractors according to claim 1, characterized in that: The step-variable transmission mechanism comprises a first transmission shaft (140) and a second transmission shaft (150); the first transmission shaft (140) and a first output shaft (160) are coaxial; the first transmission shaft (140) is loosely mounted on the first input shaft (110); the second transmission shaft (150) and the second output shaft (170) are parallel; and the second transmission shaft (150) and the first input shaft (110) are arranged at a fixed center distance.

7. A continuously variable transmission for tractors according to claim 6, characterized in that: A gear fourteen (218) is fixed on the second output shaft (170), a gear thirteen (216) is loosely mounted on the first output shaft (160), an idler wheel (217) is installed between the gear thirteen (216) and the gear fourteen (218), and the idler wheel (217) is respectively meshed with the gear thirteen (216) and the gear fourteen (218) for transmission.

8. A continuously variable transmission for tractors according to claim 1, characterized in that: A driving clutch plate group and a driven clutch plate group are fixed on the shaft system and on the shaft system and the gear group.

9. A continuously variable transmission for tractors according to claim 1, characterized in that: The shaft systems are meshed and driven by the gear sets.

10. A continuously variable transmission for tractors according to claim 1, characterized in that: The gears in the gear set are spoke-type gears, and there are fan blade structures between adjacent spokes of the spoke-type gears.

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