Small-drag direct connection four-wheel drive power transmission mechanism

Abstract

The utility model relates to power transmission device technical field especially is a kind of small tow straight connection four drive power transmission mechanism, the upper layer transmission of the sub-gearbox of this small tow straight connection four drive power transmission mechanism is straight connection transmission, lower layer transmission is four drive transmission, straight connection and four drive are ingeniously combined but do not interfere with each other, can be used flexibly, straight connection and four drive can remove any one mechanism component, and there is no influence to another transmission, powerful structure is compact and promotes;Drive is carried out through the straight connection transmission on sub-gearbox, compared with traditional belt drive, structure is reliable, transmission efficiency is high, gear shifting is smooth;The four drive transmission structure of this small tow straight connection four drive power transmission mechanism is compact and promotes unique, transmission is reliable, does not reduce ground clearance, fills the defect that traditional small tow power is small and power is insufficient, expands the use of small tow;Four drive clutch operating mechanism is arranged at the left side of sub-gearbox, and the locking mechanism arranged is simple and reliable, and the overall structure volume is small, convenient to operate, economical and practical.

Description

Technical Field

[0001] This utility model relates to the field of power transmission device technology, specifically to a small tractor direct-drive four-wheel drive power transmission mechanism. Background Technology

[0002] Small tractors are mainly used for field operations and transporting goods in rural areas. In some complex terrain operations, such as rainy, snowy, muddy roads, or mountainous areas, paddy fields, or orchards where climbing is required, four-wheel drive small tractors have obvious advantages in passing.

[0003] Four-wheel drive tractors achieve their four-wheel drive function by equipping them with a gearbox that integrates four-wheel drive capabilities. For example, in the prior art, Chinese patent document CN204186958U describes a tractor gearbox, mainly used in belt-driven four-wheel drive tractors, and Chinese patent document CN215890979U describes a four-wheel drive gearbox, also used in tractors. Existing four-wheel drive gearboxes for tractors are a single unit, which is not flexible in use and cannot be adjusted according to manufacturing requirements during production, thus hindering manufacturing efficiency and cost savings. Utility Model Content

[0004] The present invention aims to provide a direct-drive four-wheel drive power transmission mechanism for small tractors, so as to solve the technical problem that the existing small tractor gearboxes are not convenient to flexibly adjust between direct drive and four-wheel drive.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: Design a small tractor direct-drive four-wheel drive transmission mechanism, including a main gearbox, an auxiliary gearbox, and a bias gearbox. The auxiliary gearbox has a power input shaft, and the main gearbox has a direct-drive output shaft. The auxiliary gearbox, bias gearbox, and main gearbox each have a first gear transmission assembly and a second gear transmission assembly. The power input shaft is sequentially driven to the direct-drive output shaft through the first gear transmission assembly and the second gear transmission assembly. The auxiliary gearbox also has a secondary gearbox four-wheel drive output shaft. The main gearbox and auxiliary gearbox each have a third gear transmission assembly and a fourth gear transmission assembly. The third gear transmission assembly is driven to the fourth gear transmission assembly and is driven to the secondary gearbox four-wheel drive output shaft through the fourth gear transmission assembly. A four-wheel drive clutch control mechanism for operating the clutch of the fourth gear transmission assembly is provided on one side of the auxiliary gearbox.

[0006] Preferably, the power input shaft is a secondary gearbox bevel gear shaft, the first gear transmission assembly includes a secondary gearbox main drive shaft, the secondary gearbox main drive shaft is provided with a secondary gearbox large bevel gear that meshes with the bevel gear on the power input shaft; both the secondary gearbox main drive shaft and the direct-drive output shaft have one end located in the gearbox, the second gear transmission assembly includes a gearbox drive gear mounted on the secondary gearbox main drive shaft and a gearbox driven gear mounted on the direct-drive output shaft, and also includes a gearbox intermediate shaft disposed in the gearbox, the gearbox intermediate shaft is provided with a gearbox intermediate wheel located between the gearbox drive gear and the gearbox driven gear.

[0007] Preferably, the third gear transmission assembly includes a four-drive shaft driven by the direct-drive output shaft, and a main gearbox bevel gear shaft. The four-drive shaft and the main gearbox bevel gear shaft are respectively provided with meshing four-drive drive gears and four-drive driven gears. The fourth gear transmission assembly includes a secondary gearbox drive shaft. One end of the secondary gearbox drive shaft is located in the main gearbox. The main gearbox bevel gear shaft and the secondary gearbox drive shaft are respectively provided with meshing main gearbox drive bevel gears and secondary gearbox driven bevel gears. The secondary gearbox drive shaft and the secondary gearbox four-drive output shaft are respectively provided with meshing secondary gearbox power output drive gears and secondary gearbox power output driven gears.

[0008] Preferably, the four-wheel drive clutch control mechanism includes a four-wheel drive output control lever, the lower end of which is connected to a power output slide rod, the bottom of which is connected to a connecting fork, the connecting fork being connected to a four-wheel drive output lever via a connecting pin, one end of which has an oblong hole, the connecting pin being slidably disposed in the oblong hole, one end of which is connected to a four-wheel drive output shift fork assembly, the four-wheel drive output shift fork assembly having a shift fork shaft connected to the auxiliary gearbox power output driven gear, the auxiliary gearbox power output driven gear being assembled on the auxiliary gearbox four-wheel drive output shaft via a spline structure; the four-wheel drive clutch control mechanism also includes a locking assembly.

[0009] Preferably, the locking assembly includes a locking bracket disposed on the auxiliary gearbox, a locking spring disposed in the locking bracket, two locking grooves spaced apart vertically on the power output slide rod, and a locking steel ball corresponding to the locking groove at the front end of the locking spring.

[0010] Preferably, the power input shaft is located at the upper part of the auxiliary gearbox, and the auxiliary gearbox four-wheel drive output shaft is located at the lower part of the auxiliary gearbox.

[0011] Preferably, the auxiliary gearbox is connected to the front end of the main gearbox via a flange structure, and the bias gearbox and the four-wheel drive clutch control mechanism are respectively located on both sides of the main gearbox.

[0012] Preferably, the main gearbox integrates a small tractor gearbox for driving the small tractor's rear axle. Compared with the prior art, the beneficial effects of this utility model are as follows: the upper transmission of the auxiliary gearbox of the direct-drive four-wheel drive power transmission mechanism of this small tractor is a direct-drive transmission, and the lower transmission is a four-wheel drive transmission. The direct drive and four-wheel drive are cleverly combined but do not interfere with each other, allowing for flexible use. The direct drive and four-wheel drive can be used simultaneously or independently. Any one of the mechanism components can be removed without affecting the other transmission. It is powerful and compact in structure. Driven by the direct drive on the auxiliary gearbox, compared with the traditional belt drive, it has a reliable structure, high transmission efficiency, and smooth shifting. The four-wheel drive transmission structure of the direct-drive four-wheel drive power transmission mechanism of this small tractor is compact and unique, reliable in transmission, does not reduce ground clearance, and fills the defects of traditional small tractors with low power and insufficient power, thereby expanding the application of small tractors. The four-wheel drive clutch control mechanism is located on the left side of the auxiliary gearbox. The locking mechanism is simple and reliable. The overall structure is small in size, easy to operate, and economical. Attached Figure Description

[0013] The present invention will be explained in detail below with reference to the accompanying drawings. It should be noted that the drawings are used to provide a further understanding of the present invention and form part of the specification. They are used together with the embodiments of the present invention to explain the present invention, but should not impose any limitation on the implementability of the present invention.

[0014] In the attached diagram: Figure 1 This is a side view of an embodiment of the small tractor direct-drive four-wheel drive transmission mechanism of this utility model.

[0015] Figure 2 for Figure 1 AA sectional view.

[0016] Figure 3 for Figure 1 BB cross-sectional view.

[0017] Figure 4 This is a schematic diagram of the four-wheel drive clutch control mechanism in one embodiment of the small tractor direct-drive four-wheel drive power transmission mechanism of this utility model.

[0018] Figure 5 This is a schematic diagram of the connection structure between the power input shaft and the four-wheel drive output shaft of the auxiliary gearbox in one embodiment of the direct-drive four-wheel drive mechanism of this utility model.

[0019] Figure 6 for Figure 3 DD sectional view.

[0020] Figure 7 for Figure 1 EE sectional view.

[0021] In the diagram: 1. Main gearbox; 2. Direct-drive output shaft; 3. Auxiliary gearbox; 4. Auxiliary gearbox main drive shaft; 5. Auxiliary gearbox main sleeve; 6. Auxiliary gearbox main cover; 7. Power input shaft; 8. Auxiliary gearbox large bevel gear; 9. Auxiliary gearbox off-center gearbox connecting flange; 10. Off-center gearbox drive gear; 11. Off-center gearbox intermediate shaft; 12. Off-center gearbox driven gear; 13. Main gearbox right end cover; 14. Main gearbox transmission shaft right end cover; 15. Four-wheel drive shaft; 16. Four-wheel drive drive gear; 17. Four-wheel drive driven gear; 18. Main gearbox bevel gear shaft; 19. Main gearbox drive bevel gear; 20. Auxiliary gearbox driven bevel gear; 21. Auxiliary gearbox drive shaft; 22. Auxiliary gearbox power output drive gear; 23. Auxiliary gearbox... 24. Driven gearbox power output passive gear, 25. Auxiliary gearbox four-wheel drive output shaft, 26. Auxiliary gearbox end cap, 27. Auxiliary gearbox sleeve cup, 28. Four-wheel drive output lever, 281. Waist-shaped hole, 29. Connecting fork, 30. Power output slide bar, 301. Locking groove, 31. Locking support, 32. Four-wheel drive output control lever, 33. Locking steel ball, 34. Locking spring, 35. Four-wheel drive output shift fork assembly, 351. Shift fork shaft, 36. Four-wheel drive output shift fork shaft bushing, 37. Offset gearbox intermediate wheel, 38. First connecting pin, 39. Second connecting pin, 40. Third connecting pin, 41. Direct drive shaft, 42. Direct drive spline sleeve, 43. Four-wheel drive shaft, 44. Four-wheel drive connection spline sleeve. Detailed Implementation

[0022] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0023] Hereinafter, 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.

[0024] In one embodiment, a small tractor direct-drive four-wheel drive transmission mechanism is provided, such as... Figure 1 As shown, the direct-drive four-wheel drive transmission mechanism of the small tractor includes a main gearbox 1, a secondary gearbox 3, and a bias gearbox 10. The power of the small tractor engine is input to the secondary gearbox 3, the bias gearbox 10 is located between the main gearbox 1 and the secondary gearbox 3, and the secondary gearbox 3 then outputs power to the main gearbox 1 through the bias gearbox 10.

[0025] like Figure 2As shown, a power input shaft 7 is provided in the auxiliary gearbox 3, and a direct-drive output shaft 2 is provided in the main gearbox 1. The power input shaft 7 receives power from the small tractor engine, and the direct-drive output shaft 2 outputs power to drive the rear axle of the small tractor. A first gear transmission assembly and a second gear transmission assembly are respectively provided in the auxiliary gearbox 3, the bias gearbox 10, and the main gearbox 1. The power input shaft 7 is sequentially driven to the direct-drive output shaft 2 through the first gear transmission assembly and the second gear transmission assembly.

[0026] Combination Figure 5 and Figure 6 As shown, the auxiliary gearbox 3 also includes an auxiliary gearbox four-wheel drive output shaft 25. The power output from the auxiliary gearbox four-wheel drive output shaft 25 is used to drive the front axle, realizing four-wheel drive for the small tractor. The main gearbox 1 and the auxiliary gearbox 3 also respectively include a third gear transmission assembly and a fourth gear transmission assembly. The third gear transmission assembly is driven and connected to the fourth gear transmission assembly, which in turn is driven and connected to the auxiliary gearbox four-wheel drive output shaft 25. A four-wheel drive clutch control mechanism is provided on one side of the auxiliary gearbox 3 for operating the clutch of the fourth gear transmission assembly. The four-wheel drive clutch control mechanism can be used to engage and disengage the power distributed to the auxiliary gearbox four-wheel drive output shaft 25, allowing the small tractor to switch between two-wheel drive mode and four-wheel drive mode. In two-wheel drive mode, only the rear axle of the small tractor is driven, so that both rear wheels of the small tractor have power. In four-wheel drive mode, both the rear axle and the front axle of the small tractor are driven simultaneously, so that both rear wheels and the front wheels of the small tractor have power.

[0027] In this embodiment, the rear half of the main gearbox 1 is integrated with a small tractor gearbox for driving the small tractor rear axle, and the power output from the direct-connect output shaft 2 directly drives the small tractor rear axle through the small tractor gearbox.

[0028] Furthermore, such as Figure 2 As shown, the power input shaft 7 in the auxiliary gearbox 3 is an auxiliary gearbox bevel gear shaft. A bevel gear is located at one end of the power input shaft 7 within the auxiliary gearbox 3. The first gear transmission assembly includes the auxiliary gearbox main drive shaft 4, on which a large auxiliary gearbox bevel gear 8 meshes with the bevel gear on the power input shaft 7. Both the auxiliary gearbox main drive shaft 4 and the direct-drive output shaft 2 have one end located within the bias gearbox 10. The second gear transmission assembly includes a bias gearbox drive gear 11 mounted on the auxiliary gearbox main drive shaft 4 and a bias gearbox driven gear 13 mounted on the direct-drive output shaft 2. It also includes a bias gearbox intermediate shaft 12 located within the bias gearbox 3. A bias gearbox intermediate wheel 37 is located on the bias gearbox intermediate shaft 12 between the bias gearbox drive gear 11 and the bias gearbox driven gear 13, through which power is transmitted to the direct-drive output shaft 2.

[0029] Furthermore, in combination Figure 7As shown, the third gear transmission assembly includes a four-drive shaft 16 driven by a direct-drive output shaft 2. The direct-drive output shaft 2 drives the four-drive shaft 16 through a set of indirect gear shafts and indirect gears (not shown in the figure) disposed in the main gearbox 1. The third gear transmission assembly also includes a main gearbox bevel gear shaft 19, on which meshing four-drive drive gears 17 and four-drive driven gears 18 are respectively provided. Figure 6 As shown, the fourth gear transmission assembly includes a secondary gearbox drive shaft 22, one end of which is located in the main gearbox 1. The main gearbox bevel gear shaft 19 and the secondary gearbox drive shaft 22 are respectively provided with a main gearbox driving bevel gear 20 and a secondary gearbox driven bevel gear 21 that mesh with each other. The secondary gearbox drive shaft 22 and the secondary gearbox four-wheel drive output shaft 25 are respectively provided with a secondary gearbox power output driving gear 23 and a secondary gearbox power output driven gear 24 that mesh with each other, thus realizing the power distribution to the secondary gearbox four-wheel drive output shaft 25.

[0030] Furthermore, such as Figure 3 and Figure 4 As shown, the four-wheel drive clutch control mechanism includes a four-wheel drive output control lever 32. The lower end of the four-wheel drive output control lever 32 is connected to a power output slide rod 30 via a first connecting pin 38. A connecting fork 29 is connected to the bottom of the power output slide rod 30, and the connecting fork 29 is threadedly connected to the bottom of the power output slide rod 30. The connecting fork 29 is connected to a four-wheel drive output lever 28 via a second connecting pin 39. One end of the four-wheel drive output lever 28 has a waist-shaped hole 281, and the second connecting pin 39 is slidably disposed in the waist-shaped hole 28. One end of the four-wheel drive output lever 28 is connected to a four-wheel drive output shift fork assembly 35. The four-wheel drive output shift fork assembly 35 is mounted on the auxiliary gearbox 3 via a four-wheel drive output shift fork shaft bushing 36. The four-wheel drive output shift fork assembly 35 has a shift fork shaft 351 connected to the auxiliary gearbox power output driven gear 24. The auxiliary gearbox power output driven gear 24 is assembled on the auxiliary gearbox four-wheel drive output shaft 25 via a spline structure. A locking component is also provided on the four-wheel drive clutch control mechanism, such as... Figure 3 and Figure 4 As shown, the locking assembly includes a locking support 31 disposed on the auxiliary gearbox 3, a spring hole in the locking support 31, a locking spring 34 disposed in the spring hole, two locking grooves 301 spaced apart vertically on the power output slide rod 30, and a locking steel ball 33 corresponding to the locking groove 301 at the front end of the locking spring 34.

[0031] The working mode of the four-wheel drive clutch control mechanism is as follows: (1) Lift the four-wheel drive output control lever 32, pull the power output slide bar 30 through the first connecting pin 38, pull the connecting fork 29 through the threaded connection, drive the four-wheel drive output lever 28 (the connecting pin 2 can slide in the waist-shaped hole 281) to rotate along the lever axis 282 through the second connecting pin 39, drive the shift fork shaft 351 of the four-wheel drive output shift fork assembly 35 to rotate through the third connecting pin 40, drive the shift fork shaft 351 to rotate, drive the auxiliary gearbox power output passive gear 24 to slide forward along the spline of the auxiliary gearbox four-wheel drive output shaft 25, at the same time, the locking spring 34 in the locking support 31 presses the locking steel ball 33 and locks it in the lower circumferential locking groove 301 of the power output slide bar 30, the auxiliary gearbox power output passive gear 24 meshes with the auxiliary gearbox power output active gear 23 and disengages and locks, disengaging the four-wheel drive transmission. (2) Press the four-wheel drive output control lever 32 and reverse the operation of the above steps. The locking spring 34 presses the locking steel ball 33 into the upper circumferential locking groove 301 of the power output slide bar 30 and locks it. The auxiliary gearbox power output passive gear 24 meshes with the auxiliary gearbox power output active gear 23 and locks it, thus connecting the four-wheel drive transmission.

[0032] Furthermore, the power input shaft 7 of the direct-drive four-wheel drive transmission mechanism of the small tractor is located on the upper front side of the auxiliary gearbox 3, and the four-wheel drive output shaft 25 of the auxiliary gearbox is located on the lower front side of the auxiliary gearbox 3. Through this vertical distribution, the space on the front side of the auxiliary gearbox 3 is fully utilized, and the power of the small tractor engine at the front can be directly transmitted to the power input shaft 7, and the four-wheel drive output shaft 25 of the auxiliary gearbox can also directly transmit power to the front axle of the small tractor.

[0033] Combination Figure 2 As shown, the auxiliary gearbox 3 is connected to the front end of the main gearbox 1 via a flange structure. The bias gearbox 10 and the four-wheel drive clutch operating mechanism are respectively located on both sides of the auxiliary gearbox 3. An auxiliary gearbox bias gearbox connecting flange 9 is provided between the auxiliary gearbox 3 and the bias gearbox 10. The auxiliary gearbox main drive shaft 4 passes through the auxiliary gearbox bias gearbox connecting flange 9. A main gearbox right end cover 14 is provided between the main gearbox 1 and the bias gearbox 10, and the direct-drive output shaft 2 passes through the main gearbox right end cover 14. An auxiliary gearbox main sleeve cup 5 and an auxiliary gearbox main through cover 6 are provided at the front end of the auxiliary gearbox 3. The power input shaft 7 passes through the auxiliary gearbox main sleeve cup 5 and the auxiliary gearbox main through cover 6. A main gearbox shift shaft right end cover 15 is provided on the side of the main gearbox 1 to seal the shaft hole of the main gearbox 1 shift fork shaft. Figure 6 As shown, an auxiliary gearbox cover 26 and an auxiliary gearbox sleeve 27 are also provided at the front end of the auxiliary gearbox 2 for mounting the auxiliary gearbox drive shaft 22.

[0034] The working principle of this small tractor's direct-drive four-wheel drive mechanism is as follows: Direct drive means the gear mechanism directly transmits the prime mover power, transferring the diesel engine power of the small tractor directly to the main gearbox 1 via the auxiliary gearbox 3 and the bias gearbox 10. Four-wheel drive means the front axle is driven by a gear mechanism, specifically through the main gearbox 1 and the auxiliary gearbox 10, which transmit power to the four-wheel drive front axle. The four-wheel drive opening and closing mechanism is a lever self-locking mechanism located on the side of the auxiliary gearbox 3. Both the direct drive mechanism and the four-wheel drive mechanism are driven by the auxiliary gearbox 3; they can be used simultaneously or independently. Although the two mechanisms are integrated, they do not interfere with each other, offering a flexible configuration.

[0035] Direct drive operation process: The engine flywheel is directly connected via a clutch, engaging... Figure 5 As shown, the small tractor engine transmits power to the direct-drive shaft 41 via the clutch. The direct-drive shaft 41 then transmits power to the power input shaft 7 (the power input shaft 7 has a splined end) via the direct-drive spline sleeve 42. Figure 2 As shown, the power input shaft 7 transmits power to the auxiliary gearbox large bevel gear 8, which drives the auxiliary gearbox main drive shaft 4. The auxiliary gearbox main drive shaft 4 transmits power to the direct-connect output shaft 2 in the main gearbox 1 via the off-center gearbox drive gear 11, off-center gearbox intermediate shaft 12, off-center gearbox intermediate wheel 37, off-center gearbox driven gear 13 and splines. Finally, the power is transmitted to the small tractor gearbox integrated in the main gearbox 1 through the direct-connect output shaft 2.

[0036] Four-wheel drive operation process: Combining Figure 7 and Figure 6 As shown, the four-wheel drive shaft 16 transmits power to the auxiliary four-wheel drive output shaft 25 via the four-wheel drive drive gear 17, the four-wheel drive driven gear 18, the main gearbox bevel gear shaft 19, the main gearbox drive bevel gear 20, the auxiliary gearbox driven bevel gear 21, the auxiliary gearbox drive shaft 22, the auxiliary gearbox power output drive gear 23, and the auxiliary gearbox power output driven gear 24. Finally, the power is used to drive the small trailer front axle through the four-wheel drive connection spline sleeve 44, universal joint, and four-wheel drive drive shaft 43.

[0037] The structural features of the direct-drive four-wheel drive transmission mechanism of the small tractor are as follows: (1) The upper transmission of the auxiliary gearbox 3 is a direct-drive transmission, and the lower transmission is a four-wheel drive transmission. The direct drive and the four-wheel drive are cleverly combined but do not interfere with each other. For example, the direct drive can be used alone, while the four-wheel drive output shaft 25 of the auxiliary gearbox on the lower side can be left unused or the relevant four-wheel drive parts can be removed; when using the four-wheel drive alone, the direct-drive related parts and the side gearbox are removed, the original output shaft 2 is restored, the clutch pulley is installed, and the original belt drive mechanism is restored through the pulley on the engine flywheel, and the four-wheel drive mechanism can be used normally. Therefore, it can be used at the same time or individually. Any one of the mechanism parts can be removed without affecting the other transmission. It has powerful functions and a compact structure. (2) Driven by the direct drive on the auxiliary gearbox 3, compared with the traditional belt drive, the structure is reliable, the transmission efficiency is high, and the shifting is smooth. (3) The four-wheel drive transmission structure of the direct-drive four-wheel drive transmission mechanism of the small tractor is compact and unique, the transmission is reliable, and the ground clearance is not reduced. It fills the defect of the traditional small tractor's low power and insufficient power, thereby expanding the use of the small tractor. (4) The four-wheel drive clutch control mechanism is located on the left side of the auxiliary gearbox 3. The locking mechanism is simple and reliable, and the overall structure is small in size, easy to operate and economical.

[0038] It should be noted that, unless otherwise defined, all terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains, and those terms defined herein, such as those in a common dictionary, should be interpreted as having a meaning consistent with their meaning in the context of the relevant art.

[0039] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein. Those skilled in the art will readily understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. Therefore, all such modifications are intended to be included within the scope of this disclosure as defined in the claims, and will not be detailed herein.

Claims

1. A small tractor direct-drive four-wheel drive power transmission mechanism, characterized in that: The system includes a main gearbox, an auxiliary gearbox, and a bias gearbox. The auxiliary gearbox has a power input shaft, and the main gearbox has a direct-drive output shaft. The auxiliary gearbox, bias gearbox, and main gearbox each have a first gear transmission assembly and a second gear transmission assembly. The power input shaft is sequentially driven to the direct-drive output shaft through the first gear transmission assembly and the second gear transmission assembly. The auxiliary gearbox also has a four-wheel drive output shaft. The main gearbox and auxiliary gearbox each have a third gear transmission assembly and a fourth gear transmission assembly. The third gear transmission assembly is driven to the fourth gear transmission assembly and is driven to the four-wheel drive output shaft through the fourth gear transmission assembly. A four-wheel drive clutch control mechanism for operating the clutch of the fourth gear transmission assembly is provided on one side of the auxiliary gearbox.

2. The small tractor direct-drive four-wheel drive transmission mechanism according to claim 1, characterized in that: The power input shaft is a secondary gearbox bevel gear shaft. The first gear transmission assembly includes a secondary gearbox main drive shaft, on which a secondary gearbox large bevel gear is provided that meshes with the bevel gear on the power input shaft. Both the secondary gearbox main drive shaft and the direct-drive output shaft have one end located in the gearbox. The second gear transmission assembly includes a gearbox drive gear mounted on the secondary gearbox main drive shaft and a gearbox driven gear mounted on the direct-drive output shaft. It also includes a gearbox intermediate shaft disposed in the gearbox, on which a gearbox intermediate wheel is provided between the gearbox drive gear and the gearbox driven gear.

3. The small tractor direct-drive four-wheel drive transmission mechanism according to claim 1, characterized in that: The third gear transmission assembly includes a four-drive shaft driven by the direct-drive output shaft, and a main gearbox bevel gear shaft. The four-drive shaft and the main gearbox bevel gear shaft are respectively provided with meshing four-drive drive gears and four-drive driven gears. The fourth gear transmission assembly includes a secondary gearbox drive shaft. One end of the secondary gearbox drive shaft is located in the main gearbox. The main gearbox bevel gear shaft and the secondary gearbox drive shaft are respectively provided with meshing main gearbox drive bevel gears and secondary gearbox driven bevel gears. The secondary gearbox drive shaft and the secondary gearbox four-drive output shaft are respectively provided with meshing secondary gearbox power output drive gears and secondary gearbox power output driven gears.

4. The small tractor direct-drive four-wheel drive transmission mechanism according to claim 3, characterized in that: The four-wheel drive clutch control mechanism includes a four-wheel drive output control lever, the lower end of which is connected to a power output slide rod. A connecting fork is connected to the bottom of the power output slide rod, and the connecting fork is connected to a four-wheel drive output lever via a connecting pin. One end of the four-wheel drive output lever has an oblong hole, and the connecting pin is slidably disposed in the oblong hole. One end of the four-wheel drive output lever is connected to a four-wheel drive output shift fork assembly. The four-wheel drive output shift fork assembly has a shift fork shaft connected to the auxiliary gearbox power output driven gear. The auxiliary gearbox power output driven gear is assembled on the auxiliary gearbox four-wheel drive output shaft via a spline structure. The four-wheel drive clutch control mechanism also includes a locking assembly.

5. The small tractor direct-drive four-wheel drive transmission mechanism according to claim 4, characterized in that: The locking assembly includes a locking bracket disposed on the auxiliary gearbox, a locking spring disposed in the locking bracket, two locking grooves spaced apart vertically on the power output slide rod, and a locking steel ball corresponding to the locking groove at the front end of the locking spring.

6. The small tractor direct-drive four-wheel drive transmission mechanism according to claim 1, characterized in that: The power input shaft is located at the upper part of the auxiliary gearbox, and the auxiliary gearbox four-wheel drive output shaft is located at the lower part of the auxiliary gearbox.

7. The small tractor direct-drive four-wheel drive transmission mechanism according to claim 1, characterized in that: The auxiliary gearbox is connected to the front end of the main gearbox via a flange structure, and the bias gearbox and the four-wheel drive clutch control mechanism are respectively located on both sides of the auxiliary gearbox.

8. The small tractor direct-drive four-wheel drive transmission mechanism according to claim 1, characterized in that: The main gearbox integrates a small tractor gearbox for driving the small tractor rear axle.

Images