CN213799260U

CN213799260U - High-power tractor transmission system

Info

Publication number: CN213799260U
Application number: CN202023085573.9U
Authority: CN
Inventors: 陈正华; 林守信; 刘新力; 陈奇
Original assignee: Zhejiang Haitian Machinery Co ltd
Current assignee: Zhejiang Haitian Machinery Co ltd
Priority date: 2020-12-19
Filing date: 2020-12-19
Publication date: 2021-07-27
Anticipated expiration: 2030-12-19

Abstract

The utility model belongs to the technical field of vehicle transmission system, refer in particular to a high-power tractor transmission system, including clutch input shaft, clutch box output shaft, gearbox input shaft and gearbox output shaft, be equipped with high low fender wet clutch assembly on the clutch input shaft, high low fender wet clutch assembly includes high fender clutch and low fender clutch, and gearbox input shaft and gearbox output shaft are through a plurality of gear drive, and shift position switching is carried out by the synchronizer of electric liquid control. The utility model has the advantages that by means of the characteristic that the power of the high-low gear wet clutch assembly is not interrupted when the gear is shifted, the electro-hydraulic gear shifting actuator is quickly combined with the synchronizer after the quick oil filling of the clutch is finished under the coordination of a control program and the transmission ratio of adjacent gears, so that the power flow is not interrupted under the working condition of heavy-load traction operation, and the adjacent gears can realize smooth, sequential and continuous non-impact gear shifting; the structure is simple, the transmission efficiency is high, the cost is low, and the transmission ratio curve is approximate to stepless speed change.

Description

High-power tractor transmission system

The technical field is as follows:

the utility model belongs to the technical field of vehicle transmission system, refer in particular to a high-power tractor transmission system.

Background art:

at present, a tractor produced in China generally adopts a stepped mechanical gear shifting gearbox controlled by a dry clutch, the clutch is firstly separated when the gearbox shifts gears, so that the transmission power flow is interrupted, and particularly, the operation quality cannot meet the agricultural requirement under the heavy-load traction working condition due to the change of soil specific resistance. Resulting in increased engine oil consumption and reduced production efficiency. The tractor adopting high-low gear power shifting can well realize gear shifting during heavy-load operation to a certain extent without interrupting power flow, but the speed range is narrow. Gearbox gear shifting relies on manual shifting, and the ratio discontinuity of each gear can cause the power flow to break. Therefore, when the tractor faces different working conditions, the engine cannot be always in the optimal working condition. The existing tractor with stepless speed change developed in the developed countries realizes stepless speed change under the cooperation of a controller by means of the combination of a variable pump, a variable (fixed) motor and a plurality of planet bars in a shunting and converging way, and has high cost and low transmission efficiency. The full-power gear-shifting tractor adopts a plurality of wet clutches for transmission, has higher transmission efficiency, but has complex control and high cost.

In addition, when unmanned field operation is carried out, a tractor provided with the stepped mechanical gear shifting gearbox can only be limited to a certain gear and runs at a fixed speed, because the gear shifting time required by the conventional stepped mechanical gear shifting is too long, once the gear shifting is carried out, the dry clutch needs to be separated, and under the working condition of heavy-load traction operation in the field, the traction resistance is large during the field operation, the operation speed is reduced quickly, and the power flow is interrupted.

The invention content is as follows:

the utility model aims at providing a high-power tractor transmission system, which has high transmission efficiency and low cost, and the high-low gear wet clutch finishes the joint of the electro-hydraulic control synchronizer when shifting gears and charging oil, thereby effectively shortening the gear shifting time and avoiding the interruption of power flow; when in design, the transmission ratio of adjacent gears is small, the speed array conforms to an equal ratio series, and the common ratio is small; the transmission ratio curve tends to be infinitely variable.

The utility model discloses a realize like this:

a high-power tractor transmission system comprises a clutch input shaft, a clutch output shaft, a gearbox input shaft, a gearbox output shaft, a rear axle assembly input shaft and a rear axle assembly output shaft, wherein the clutch input shaft and the clutch output shaft are in transmission connection through a high-low gear wet clutch assembly, the high-low gear wet clutch assembly comprises a high-gear clutch and a low-gear clutch which are sleeved on the clutch input shaft, a high-gear normally-meshed gear meshed with the high-gear clutch and a low-gear normally-meshed gear meshed with the low-gear clutch are fixedly sleeved on the clutch output shaft, the gearbox input shaft is in linkage with the clutch output shaft, the gearbox input shaft and the gearbox output shaft are in transmission connection through a plurality of transmission gear sets, and the gearbox output shaft synchronously rotates with the corresponding transmission gear set through a hydraulic synchronizer driven by an electro-hydraulic control shifting cylinder, the output shaft of the gearbox is linked with the input shaft of the rear axle assembly, the input shaft of the rear axle assembly is in transmission connection with the output shaft of the rear axle assembly through a plurality of speed gear sets, and the input shaft of the rear axle assembly or/and the output shaft of the rear axle assembly synchronously rotate with the gear sets with corresponding speeds through a speed section synchronizer.

In the transmission system of the high-power tractor, the transmission gear set comprises a first-gear driving gear, a second-gear driving gear, a third-gear driving gear and a fourth-gear driving gear which are sleeved on the input shaft of the gearbox, a first-gear driven gear meshed with the first-gear driving gear, a second-gear driven gear meshed with the second-gear driving gear, a third-gear driven gear meshed with the third-gear driving gear and a fourth-gear driven gear meshed with the fourth-gear driving gear are sleeved on the output shaft of the gearbox, two hydraulic synchronizers are arranged and are respectively positioned between the first-gear driven gear and the second-gear driven gear and between the third-gear driven gear and the fourth-gear driven gear, and the electro-hydraulic control gear shifting oil cylinder drives the hydraulic synchronizers to be connected with the corresponding driven gears so as to realize synchronous rotation of the corresponding driven gears and the output shaft of the gearbox.

In the transmission system of the high-power tractor, the speed gear set comprises an a-gear driving gear, a B-gear driving gear, a C-gear driving gear and a D-gear driving gear which are sleeved on the input shaft of the rear axle assembly, the output shaft of the rear axle assembly is sleeved with an a-gear driven gear meshed with the a-gear driving gear, a B-gear driven gear meshed with the B-gear driving gear, a C-gear driven gear meshed with the C-gear driving gear and a D-gear driven gear meshed with the D-gear driving gear, the speed section synchronizer is provided with two low-gear synchronizers respectively sleeved on the output shaft of the rear axle assembly and a high-gear synchronizer sleeved on the input shaft of the rear axle assembly, the low-gear synchronizer is positioned between the a-gear driven gear and the B-gear driven gear, and is connected with the a-gear driven gear or the B-gear driven gear by the low-gear synchronizer to realize the synchronous rotation of the input shaft of the rear axle assembly and the a-gear driven gear or the B-gear driven gear, the high-gear synchronizer is positioned between the C-gear driving gear and the D-gear driving gear and is engaged with the C-gear driving gear or the D-gear driving gear to realize synchronous rotation of the output shaft of the rear axle assembly and the C-gear driving gear or the D-gear driving gear.

In the transmission system of the high-power tractor, the clutch input shaft and the transmission output shaft are positioned on the same axis, the transmission output shaft is a hollow shaft, the inner hole of the transmission output shaft is provided with the PTO linkage shaft, one end of the PTO linkage shaft is linked with the clutch input shaft through a coupler, the other end of the PTO linkage shaft is in transmission connection with the PTO intermediate shaft through the PTO clutch, and the PTO intermediate shaft is in transmission connection with the PTO output shaft through the PTO transmission gear set.

In the transmission system of the high-power tractor, the PTO transmission gear set comprises a PTO low-gear driving gear and a PTO high-gear driving gear which are sleeved on the PTO linkage shaft, a PTO low-gear driven gear meshed with the PTO low-gear driving gear and a PTO high-gear driven gear meshed with the PTO high-gear driving gear are sleeved on the PTO output shaft, and the PTO output shaft is connected with the PTO low-gear driven gear or the PTO high-gear driven gear through a PTO synchronizer so as to realize the synchronous rotation of the PTO output shaft and the PTO low-gear driven gear or the PTO high-gear driven gear.

In foretell high-power tractor transmission system, still including the jackshaft that reverses gear, the cover is equipped with the constant mesh gear that reverses gear and with the synchronous pivoted driving gear that reverses gear constant mesh gear on the jackshaft that reverses gear, clutch input shaft passes through the clutch that reverses gear and the meshing of the constant mesh gear that reverses gear, the cover is equipped with the driven gear that reverses gear with the driving gear meshing that reverses gear on the clutch output shaft.

In the transmission system of the high-power tractor, the output shaft of the rear axle assembly is in meshed transmission with the differential assembly through the output bevel gear, and two output ends of the differential assembly are in transmission connection with the left half shaft and the right half shaft through the planetary gear sets respectively.

In the transmission system of the high-power tractor, the transmission system further comprises a 4WD intermediate shaft and a 4WD output shaft, wherein the 4WD intermediate shaft is sleeved with a 4WD constant mesh gear meshed with the C-gear driven gear, the 4WD output shaft is sleeved with a 4WD driving gear meshed with the 4WD constant mesh gear, and the 4WD output shaft is connected with the 4WD driving gear through a 4WD synchronizer so as to realize synchronous rotation of the 4WD output shaft and the 4WD driving gear.

Compared with the prior art, the utility model outstanding advantage is:

the utility model has the advantages that by means of the characteristic that the power of the high-low gear wet clutch is not interrupted when the gear is shifted, the electro-hydraulic gear shifting actuator is quickly combined with the synchronizer after the quick oil filling of the clutch is finished under the coordination of a control program and the transmission ratio of adjacent gears, so that the power flow is not interrupted under the working condition of heavy-load traction operation, and the adjacent gears can realize smooth, sequential and continuous impact-free gear shifting; the transmission ratio curve is approximate to stepless speed change, and the unmanned driving operation requirement can be met.

Description of the drawings:

FIG. 1 is a mechanical schematic diagram of the chassis transmission of the present invention;

fig. 2 is a schematic diagram of a gear and speed curve of the present invention.

In the figure: 1. a clutch input shaft; 2. a clutch output shaft; 3. a transmission input shaft; 4. a gearbox output shaft; 5. a rear axle assembly input shaft; 6. a rear axle assembly output shaft; 7. a high-low gear wet clutch assembly; 8. a high range clutch; 9. a low range clutch; 10. a high-gear normally meshed gear; 11. a low-gear normally meshed gear; 12. a gear shifting oil cylinder; 13. a hydraulic synchronizer; 14. a first gear driving gear; 15. a second gear driving gear; 16. a third gear drive gear; 17. a fourth gear drive gear; 18. a first-gear driven gear; 19. a second driven gear; 20. a third-gear driven gear; 21. a fourth-gear driven gear; 22. the gear A is a driving gear; 23. a B gear driving gear; 24. a C gear driving gear; 25. a D gear driving gear; 26. a gear A driven gear; 27. a B-gear driven gear; 28. a C-gear driven gear; 29. a D-gear driven gear; 30. a low range synchronizer; 31. a high gear synchronizer; 32. a PTO universal joint shaft; 33. a PTO clutch; 34. a PTO countershaft; 35. a PTO output shaft; 36. a PTO low range drive gear; 37. a PTO high range drive gear; 38. a PTO low range driven gear; 39. a PTO high-speed driven gear; 40. a PTO synchronizer; 41. a reverse gear intermediate shaft; 42. a reverse gear constant mesh gear; 43. a reverse drive gear; 44. a reverse clutch; 45. a reverse driven gear; 46. an output bevel gear; 47. a differential assembly; 48. a left half shaft; 49. a right half shaft; 50. a 4WD countershaft; 51. a 4WD output shaft; 52. 4WD constant mesh gear; 53. 4WD drive gear; 54. 4WD synchronizer.

The specific implementation mode is as follows:

the invention will now be further described with reference to specific embodiments, with reference to figures 1-2:

a high-power tractor transmission system comprises a clutch input shaft 1, a clutch output shaft 2, a gearbox input shaft 3, a gearbox output shaft 4, a rear axle assembly input shaft 5 and a rear axle assembly output shaft 6, wherein the clutch input shaft 1 and the clutch output shaft 2 are in transmission connection through a high-low gear wet clutch assembly 7, the high-low gear wet clutch assembly 7 comprises a high-gear clutch 8 and a low-gear clutch 9 which are sleeved on the clutch input shaft 1, the clutch output shaft 2 is fixedly sleeved with a high-gear normally-meshed gear 10 meshed with the high-gear clutch 8 and a low-gear normally-meshed gear 11 meshed with the low-gear clutch 9, the gearbox input shaft 3 is linked with the clutch output shaft 2, the gearbox input shaft 3 is in transmission connection with the gearbox output shaft 4 through a plurality of transmission gear sets, and the gearbox output shaft 4 synchronously rotates with the corresponding transmission gear set through a hydraulic synchronizer 13 driven by an electro-hydraulic control gear shifting oil cylinder 12, the gearbox output shaft 4 is linked with the rear axle assembly input shaft 5, the rear axle assembly input shaft 5 is in transmission connection with the rear axle assembly output shaft 6 through a plurality of speed gear sets, and the rear axle assembly input shaft 5 or/and the rear axle assembly output shaft 6 synchronously rotate with the corresponding speed gear sets through the speed section synchronizer.

The utility model discloses keep off the characteristic that wet clutch was not interrupted when shifting with the help of height, height keeps off wet clutch assembly 7 promptly and can realize the high fast switch-over between clutch 8 and the low clutch 9 that keeps off in the short time, and simultaneously, because adjacent transmission keeps off the continuous just common ratio of drive ratio between the position less, the hydraulic pressure synchronizer 13 of the hydro-hydraulic control hydro-cylinder 12 driven of shifting can accomplish the joint of shifting fast after the oil charge of height keeps off wet clutch assembly 7 ends, guarantee that the power flow does not break under the heavy load traction operation operating mode, make adjacent fender position can realize level and smooth, order, continuous no impact is shifted, shift the time of shifting has effectively been shortened, a structure is simple, high transmission efficiency, with low costs and drive ratio curve approximate infinitely variable, can satisfy unmanned driving operation demand.

Under the normal working condition, the oil filling time of the high-low gear wet clutch assembly 7 is within 0.3s, and under the heavy-load traction working condition, the time required by the high-low gear wet clutch assembly 7 to switch from the low gear to the high gear is within 1.0s-1.2 s.

Meanwhile, in this embodiment, the transmission gears include four gears, and the specific structure thereof is: the transmission gear set comprises a first gear driving gear 14, a second gear driving gear 15, a third gear driving gear 16 and a fourth gear driving gear 17 which are sleeved on the transmission input shaft 3, a first gear driven gear 18 meshed with the first gear driving gear 14, a second gear driven gear 19 meshed with the second gear driving gear 15, a third gear driven gear 20 meshed with the third gear driving gear 16 and a fourth gear driven gear 21 meshed with the fourth gear driving gear 17 are sleeved on the transmission output shaft 4, and the hydraulic synchronizer 13 is provided with two gears and is respectively located between the first gear driven gear 18 and the second gear driven gear 19 and between the third gear driven gear 20 and the fourth gear driven gear 21.

Correspondingly, the two shift cylinders 12 are also arranged and correspond to the hydraulic synchronizers 13 one by one, and the electro-hydraulic control shift cylinders 12 drive the corresponding hydraulic synchronizers 13 to be connected with the corresponding driven gears. Thus, by controlling the engagement of the high-low gear wet clutch assembly 7 and the hydraulic synchronizer 13, the following gears can be formed: 1. l formed by engagement of the low clutch 9 and engagement of the hydraulic synchronizer 13 with a one-speed driven gear 18₁A gear position; 2. h formed by engagement of high clutch 8 and engagement of one-speed driven gear 18 by hydraulic synchronizer 13₁A gear position; 3. l formed by engagement of the low clutch 9 and engagement of the second driven gear 19 by the hydraulic synchronizer 13₂A gear position; 4. h formed by engagement of high-gear clutch 8 and engagement of two-gear driven gear 19 by hydraulic synchronizer 13₂A gear position; 5. l formed by engagement of low clutch 9 and engagement of third driven gear 20 by hydraulic synchronizer 13₃A gear position; 6. h formed by engagement of high clutch 8 and engagement of third driven gear 20 by hydraulic synchronizer 13₃A gear position; 7. l formed by engagement of the low clutch 9 and engagement of the fourth driven gear 21 by the hydraulic synchronizer 13₄A gear position; 8. h formed by engagement of the high clutch 8 and engagement of the fourth driven gear 21 by the hydraulic synchronizer 13₄And (4) gear position.

And will be shifted in the following order: l is₁→H₁→L₂→H₂→L₃→H₃→L₄→H₄. The gear transmission ratios are continuous, the transmission ratio common ratio of adjacent gears is small, the shifting axial force of the hydraulic synchronizer 13 is large, and the shifting engagement can be completed within 0.3s in the oil filling process of the high-low gear wet clutch assembly 7.

Meanwhile, the utility model discloses when going at high speed, can slow down in order to realize shifting under the cooperation of stopper, and when field operation and need turn around, but self-actuating brake keeps off the position in order to reduce, realizes turning to the radius switching-over for a short time.

Furthermore, in the present embodiment, four speed range gears are provided, and the specific speed gear transmission structure is: the speed gear set comprises an A-gear driving gear 22, a B-gear driving gear 23, a C-gear driving gear 24 and a D-gear driving gear 25 which are sleeved on a rear axle assembly input shaft 5, an A-gear driven gear 26 meshed with the A-gear driving gear 22, a B-gear driven gear 27 meshed with the B-gear driving gear 23, a C-gear driven gear 28 meshed with the C-gear driving gear 24 and a D-gear driven gear 29 meshed with the D-gear driving gear 25 are sleeved on a rear axle assembly output shaft 6, two speed section synchronizers are arranged and respectively provided for a low-gear synchronizer 30 sleeved on the rear axle assembly output shaft 6 and a high-gear synchronizer 31 sleeved on the rear axle assembly input shaft 5, the low-gear synchronizer 30 is positioned between the A-gear driven gear 26 and the B-gear driven gear 27, and the low-gear synchronizer 30 is connected with the A-gear driven gear 26 or the B-gear driven gear 27, The high-gear synchronizer 31 is positioned between the C-gear driving gear 24 and the D-gear driving gear 25, and the high-gear synchronizer 31 is engaged with the C-gear driving gear 24 or the D-gear driving gear 25 to realize synchronous rotation of the output shaft of the rear axle assembly and the C-gear driving gear 24 or the D-gear driving gear 25. Meanwhile, the shifting operation of the low-gear synchronizer 30 and the high-gear synchronizer 31 is manual or electric control operation, and the gear engagement is completed before the actual working condition operation to be performed.

Thus, in the above speed gear transmission configuration the following gear speed ranges can be formed: the speed control device includes an a-range speed section formed by engagement of the low synchronizer 30 with the a-range driven gear 26, a B-range speed section formed by engagement of the low synchronizer 30 with the B-range driven gear 27, a C-range speed section formed by engagement of the high synchronizer 31 with the C-range driving gear 24, and a D-range speed section formed by engagement of the high synchronizer 31 with the D-range driving gear 25. The speed of the gear A speed interval, the speed of the gear B speed interval and the speed of the gear C speed interval are small, the gear A speed interval, the speed of the gear B speed interval and the speed of the gear C speed interval are suitable for various working condition operations in a field, and the gear A speed interval, the speed of the gear B speed interval and the speed of the gear C speed interval are respectively a power output operation gear, a medium-load traction operation gear and a heavy-load traction operation gear; and the speed of the D gear speed interval is larger, so that the D gear speed interval is suitable for road transportation work operation and is a road transportation work gear. Meanwhile, in the embodiment, the interval range of the speed interval of the gear C is large, and the speed covered by the speed interval can completely meet the requirement of unmanned operation.

Further, because the utility model discloses can be applied to the tractor on, consequently, the concrete transmission structure of the PTO transmission system that the tractor will possess is: the clutch input shaft 1 and the gearbox output shaft 4 are located on the same axis, the gearbox output shaft 4 is a hollow shaft, a PTO linkage shaft 32 is arranged in an inner hole of the gearbox output shaft 4, one end of the PTO linkage shaft 32 is in linkage with the clutch input shaft 1 through a coupler, the other end of the PTO linkage shaft is in transmission connection with a PTO intermediate shaft 34 through a PTO clutch 33, and the PTO intermediate shaft 34 is in transmission connection with a PTO output shaft 35 through a PTO transmission gear set.

In addition, in this embodiment, the PTO transmission system has two transmission gears, and the specific transmission gear structure thereof is: the PTO transmission gear set comprises a PTO low-gear driving gear 36 and a PTO high-gear driving gear 37 which are sleeved on the PTO linkage shaft 32, a PTO low-gear driven gear 38 meshed with the PTO low-gear driving gear 36 and a PTO high-gear driven gear 39 meshed with the PTO high-gear driving gear 37 are sleeved on the PTO output shaft 35, and the PTO output shaft 35 is connected with the PTO low-gear driven gear 38 or the PTO high-gear driven gear 39 through a PTO synchronizer 40 so as to realize synchronous rotation of the PTO output shaft 35 and the PTO low-gear driven gear 38 or the PTO high-gear driven gear 39. Namely, the PTO low gear formed by combining the PTO synchronizer 40 and the PTO low gear driven gear 38, and the PTO high gear formed by combining the PTO synchronizer 40 and the PTO high gear driven gear 39, the output rotating speeds of the PTO low gear and the PTO high gear can effectively meet the requirement of field operation on the vehicle speed.

Further, the utility model discloses the concrete transmission structure of reversing gear does: the clutch is characterized by further comprising a reverse gear intermediate shaft 41, wherein a reverse gear normally-meshed gear 42 and a reverse gear driving gear 43 synchronously rotating with the reverse gear normally-meshed gear 42 are sleeved on the reverse gear intermediate shaft 41, the clutch input shaft 1 is meshed with the reverse gear normally-meshed gear 42 through a reverse gear clutch 44, and a reverse gear driven gear 45 meshed with the reverse gear driving gear 43 is sleeved on the clutch output shaft 2.

Furthermore, the transmission structure between the output shaft 6 of the rear axle assembly and the two rear driving wheels is as follows: the rear axle assembly output shaft 6 is in meshed transmission with a differential assembly 47 through an output bevel gear 46, two output ends of the differential assembly 47 are in transmission connection with a left half shaft 48 and a right half shaft 49 through planetary gear sets respectively, and two rear driving wheels of the differential assembly are connected with the left half shaft 48 and the right half shaft 49 respectively.

Meanwhile, the present embodiment is applied to four-wheel drive, and further includes a 4WD intermediate shaft 50 and a 4WD output shaft 51, the 4WD intermediate shaft 50 is sleeved with a 4WD constant mesh gear 52 meshed with the C-range driven gear 28, the 4WD output shaft 51 is sleeved with a 4WD drive gear 53 meshed with the 4WD constant mesh gear 52, and the 4WD output shaft 51 is engaged with the 4WD drive gear 53 through a 4WD synchronizer 54 to realize synchronous rotation of the 4WD output shaft 51 and the 4WD drive gear 53.

The above-mentioned embodiment is only one of the preferred embodiments of the present invention, and the scope of the present invention is not limited thereto, so: all equivalent changes made according to the shape, structure and principle of the utility model are covered within the protection scope of the utility model.

Claims

1. A high-power tractor transmission system which characterized in that: the clutch transmission comprises a clutch input shaft (1), a clutch output shaft (2), a transmission input shaft (3), a transmission output shaft (4), a rear axle assembly input shaft (5) and a rear axle assembly output shaft (6), wherein the clutch input shaft (1) and the clutch output shaft (2) are in transmission connection through a high-low gear wet clutch assembly (7), the high-low gear wet clutch assembly (7) comprises a high-gear clutch (8) and a low-gear clutch (9) which are sleeved on the clutch input shaft (1), the clutch output shaft (2) is fixedly sleeved with a high-gear normally-meshed gear (10) meshed with the high-gear clutch (8) and a low-gear normally-meshed gear (11) meshed with the low-gear clutch (9), the transmission input shaft (3) is linked with the clutch output shaft (2), and the transmission input shaft (3) and the transmission output shaft (4) are in transmission connection through a plurality of transmission gear sets, And a gearbox output shaft (4) synchronously rotates with a corresponding transmission gear set through a hydraulic synchronizer (13) driven by an electro-hydraulic control gear shifting oil cylinder (12), the gearbox output shaft (4) is linked with a rear axle assembly input shaft (5), the rear axle assembly input shaft (5) is in transmission connection with a rear axle assembly output shaft (6) through a plurality of speed gear sets, and the rear axle assembly input shaft (5) or/and the rear axle assembly output shaft (6) synchronously rotates with the corresponding speed gear set through a speed zone synchronizer.

2. A high power tractor drive system according to claim 1, characterised in that: the transmission gear set comprises a first-gear driving gear (14), a second-gear driving gear (15), a third-gear driving gear (16) and a fourth-gear driving gear (17) which are sleeved on a transmission input shaft (3), a first-gear driven gear (18) meshed with the first-gear driving gear (14), a second-gear driven gear (19) meshed with the second-gear driving gear (15), a third-gear driven gear (20) meshed with the third-gear driving gear (16) and a fourth-gear driven gear (21) meshed with the fourth-gear driving gear (17) are sleeved on a transmission output shaft (4), two hydraulic synchronizers (13) are arranged and are respectively positioned between the first-gear driven gear (18) and the second-gear driven gear (19) and between the third-gear driven gear (20) and the fourth-gear driven gear (21), and an electro-hydraulic control oil cylinder (12) drives a hydraulic synchronizer (13) to be connected with a corresponding driven gear, So as to realize the synchronous rotation of the corresponding driven gear and the output shaft (4) of the gearbox.

3. A high power tractor drive system according to claim 1, characterised in that: the speed gear set comprises an A gear driving gear (22), a B gear driving gear (23), a C gear driving gear (24) and a D gear driving gear (25) which are sleeved on a rear axle assembly input shaft (5), an A gear driven gear (26) meshed with the A gear driving gear (22), a B gear driven gear (27) meshed with the B gear driving gear (23), a C gear driven gear (28) meshed with the C gear driving gear (24) and a D gear driven gear (29) meshed with the D gear driving gear (25) are sleeved on a rear axle assembly output shaft (6), two speed section synchronizers are arranged and respectively provided as a low gear synchronizer (30) sleeved on the rear axle assembly output shaft (6) and a high gear synchronizer (31) sleeved on the rear axle assembly input shaft (5), and the low gear synchronizer (30) is positioned between the A gear driven gear (26) and the B gear driven gear (27), the low-gear synchronizer (30) is connected with the A-gear driven gear (26) or the B-gear driven gear (27) to realize synchronous rotation of the rear axle assembly input shaft (5) and the A-gear driven gear (26) or the B-gear driven gear (27), the high-gear synchronizer (31) is located between the C-gear driving gear (24) and the D-gear driving gear (25), and the high-gear synchronizer (31) is connected with the C-gear driving gear (24) or the D-gear driving gear (25) to realize synchronous rotation of the rear axle assembly output shaft and the C-gear driving gear (24) or the D-gear driving gear (25).

4. A high power tractor drive system according to claim 1, characterised in that: the clutch input shaft (1) and the gearbox output shaft (4) are located on the same axis, the gearbox output shaft (4) is a hollow shaft, a PTO linkage shaft (32) is arranged in an inner hole of the gearbox output shaft (4), one end of the PTO linkage shaft (32) is in linkage with the clutch input shaft (1) through a coupler, the other end of the PTO linkage shaft is in transmission connection with a PTO intermediate shaft (34) through a PTO clutch (33), and the PTO intermediate shaft (34) is in transmission connection with a PTO output shaft (35) through a PTO transmission gear set.

5. A high power tractor drive system according to claim 4, characterised in that: the PTO transmission gear set comprises a PTO low-gear driving gear (36) and a PTO high-gear driving gear (37) which are sleeved on a PTO linkage shaft (32), a PTO low-gear driven gear (38) meshed with the PTO low-gear driving gear (36) and a PTO high-gear driven gear (39) meshed with the PTO high-gear driving gear (37) are sleeved on a PTO output shaft (35), and the PTO output shaft (35) is connected with the PTO low-gear driven gear (38) or the PTO high-gear driven gear (39) through a PTO synchronizer (40) to realize synchronous rotation of the PTO output shaft (35) and the PTO low-gear driven gear (38) or the PTO high-gear driven gear (39).

6. A high power tractor drive system according to claim 1, 2 or 3, characterised in that: the clutch is characterized by further comprising a reverse gear intermediate shaft (41), wherein the reverse gear intermediate shaft (41) is sleeved with a reverse gear normally-meshed gear (42) and a reverse gear driving gear (43) which synchronously rotates with the reverse gear normally-meshed gear (42), the clutch input shaft (1) is meshed with the reverse gear normally-meshed gear (42) through a reverse gear clutch (44), and the clutch output shaft (2) is sleeved with a reverse gear driven gear (45) meshed with the reverse gear driving gear (43).

7. A high power tractor drive system according to claim 1, characterised in that: the rear axle assembly output shaft (6) is in meshed transmission with the differential assembly (47) through an output bevel gear (46), and two output ends of the differential assembly (47) are in transmission connection with a left half shaft (48) and a right half shaft (49) through planetary gear sets respectively.

8. A high power tractor drive system according to claim 3, characterised in that: the transmission mechanism further comprises a 4WD intermediate shaft (50) and a 4WD output shaft (51), wherein the 4WD intermediate shaft (50) is sleeved with a 4WD normally-meshed gear (52) meshed with the C-gear driven gear (28), the 4WD output shaft (51) is sleeved with a 4WD driving gear (53) meshed with the 4WD normally-meshed gear (52), and the 4WD output shaft (51) is connected with the 4WD driving gear (53) through a 4WD synchronizer (54) to realize synchronous rotation of the 4WD output shaft (51) and the 4WD driving gear (53).