Transmission system of combine harvester

Abstract

The invention belongs to the technical field of agricultural machinery, and relates to a transmission system of a combine harvester, which comprises a transmission case, one end of a transmission shaft in the transmission case is sleeved with a forward driving wheel, and the forward driving wheel is in transmission connection with a conveying driving shaft through a forward conveying belt and drives the conveying driving shaft to rotate forward. The other end of the transmission shaft is coaxially provided with a hollow shaft in clearance fit, the transmission shaft and the hollow shaft are in transmission connection through a bevel gear set and have opposite rotation directions, the hollow shaft is sleeved with a reverse driving wheel, and the reverse driving wheel is in transmission connection with the conveying driving shaft through a reverse conveying belt and drives the conveying driving shaft to rotate reversely. The forward conveying belt and the reverse conveying belt are correspondingly provided with a forward tensioning wheel and a reverse tensioning wheel respectively, the forward tensioning wheel and the reverse tensioning wheel are connected to the two ends of a forward and reverse rotation switching connecting rod respectively, and the tensioning state of the forward tensioning wheel and the tensioning state of the reverse tensioning wheel are switched through the forward and reverse rotation switching connecting rod. The transmission system of the combine harvester has the advantages of being simple in structure, stable in transmission and convenient to switch.

Description

Technical Field

[0001] The invention belongs to the technical field of agricultural machinery and relates to a transmission system of a combine harvester. Background Art

[0002] When the combine harvester is working together, the cut crop stems are transported through the conveying trough of the conveying device. During the transportation process, the crop stems in the conveying trough may be blocked by grass. At this time, it is necessary to reverse the conveying device to withdraw the grass and then transport the crop stems again. The grass withdrawal mechanism of the existing combine harvester is generally completed by a clutch: a forward clutch and a reverse clutch are provided on the transmission input shaft, and the transmission input shaft and the harvesting input shaft are linked by the forward clutch and the reverse clutch to transmit the forward and reverse driving forces to the harvesting input shaft of the harvesting part.

[0003] Chinese invention patent application CN 106068899 A discloses a conveying trough of a combine harvester with forward conveying and reverse weeding functions, including a conveying trough shell, a chain rake, a support plate, a transmission and a tensioner. The invention cuts off and connects the power between the power output shaft of the threshing drum of the combine harvester and the power input shaft of the conveying trough through a set of tensioning wheel mechanisms, and transmits power by means of constant meshing of bevel gears in a forward and reverse transmission box. The driver pulls a handle on the driving console to control the reversing operation of the power connecting shaft in the forward and reverse transmission box.

[0004] The above-mentioned combine harvester's reversing method is to use the shift fork to shift the power connection shaft, thereby changing the gear meshing method to achieve different power transmission. Therefore, its essence is also equivalent to a clutch device, which achieves different power transmission by changing the position of the transmission component in the transmission box. In view of this, it is necessary to develop a clutch structure that is truly separated from the transmission box to achieve a reversing transmission system. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a transmission system for a combine harvester, which has the advantages of simple structure, stable transmission and convenient switching.

[0006] In order to solve the above technical problems, the purpose of the present invention is achieved through the following technical solutions:

[0007] A transmission system of a combine harvester comprises a transmission box, a conveying mechanism and a threshing mechanism, wherein the transmission box transmits power forward to drive the conveying mechanism and transmits power backward to drive the threshing mechanism, wherein an engine-driven transmission shaft is arranged in the transmission box, a forward driving wheel is sleeved on one end of the transmission shaft, the forward driving wheel is connected to the conveying driving shaft through a forward conveying belt transmission and drives it to rotate forward, a hollow shaft with a clearance fit is coaxially arranged on the other end of the transmission shaft, the transmission shaft and the hollow shaft are connected through a bevel gear set and have opposite rotation directions, a reverse driving wheel is sleeved on the hollow shaft, the reverse driving wheel is connected to the conveying driving shaft through a reverse conveying belt transmission and drives it to rotate in the reverse direction, the forward conveying belt and the reverse conveying belt are respectively provided with a forward tensioning wheel and a reverse tensioning wheel, the forward tensioning wheel and the reverse tensioning wheel are respectively connected to the two ends of the forward and reverse switching connecting rod and the tensioning state is switched by them: when the forward tensioning wheel tensions the forward conveying belt, the conveying mechanism conveys forward; when the reverse tensioning wheel tensions the reverse conveying belt, the conveying mechanism conveys reversely.

[0008] In the above-mentioned transmission system of a combine harvester, the bevel gear set includes a first bevel gear mounted on the transmission shaft, a second bevel gear mounted on the hollow shaft, and a third bevel gear mounted on the threshing drive shaft. The first bevel gear and the second bevel gear are simultaneously meshed with the third bevel gear for transmission, and the intersection angle between the transmission shaft, the hollow shaft and the threshing drive shaft is 90°.

[0009] In the above-mentioned transmission system of a combine harvester, a main power wheel is mounted on one end of the transmission shaft, the main power wheel is connected to the engine through a main power belt, and the main power wheel is located outside the forward drive wheel and is integrally formed with the forward drive wheel.

[0010] In the above-mentioned transmission system of a combine harvester, the other end of the transmission shaft extends out of the hollow shaft and is mounted with a fan driving wheel, the fan driving wheel is located on the outside of the reverse driving wheel, the fan driving wheel is connected to the fan driving shaft through a fan driving belt, the fan driving shaft drives the fan mechanism to work, and the fan mechanism is arranged below the threshing mechanism, and its air outlet faces the bottom of the threshing mechanism.

[0011] In the above-mentioned transmission system of a combine harvester, the transmission shaft, the hollow shaft, the threshing transmission shaft and the transmission box are all supported by a plurality of bearings, the reverse drive wheel extends outwardly to form a reverse drive wheel bearing mounting seat, and a bearing is arranged between the reverse drive wheel bearing mounting seat and the transmission shaft.

[0012] In the above-mentioned transmission system of a combine harvester, the forward tensioning wheel is arranged on the front side of the forward conveying belt, and the reverse tensioning wheel is arranged on the rear side of the reverse conveying belt; or, the forward tensioning wheel is arranged on the rear side of the forward conveying belt, and the reverse tensioning wheel is arranged on the front side of the reverse conveying belt; the forward-reverse switching connecting rod drives the forward tensioning wheel and the reverse tensioning wheel to rotate in the same direction to switch the tensioning state. Specifically, when the forward-reverse switching link drives the forward tensioning wheel and the reverse tensioning wheel to rotate backward, the forward tensioning wheel tensions the forward conveying belt, and when the forward-reverse switching link drives the forward tensioning wheel and the reverse tensioning wheel to rotate forward, the reverse tensioning wheel tensions the reverse conveying belt; or, the forward tensioning wheel is arranged on the rear side of the forward conveying belt, and the reverse tensioning wheel is arranged on the front side of the reverse conveying belt, and when the forward-reverse switching link drives the forward tensioning wheel and the reverse tensioning wheel to rotate backward, the reverse tensioning wheel tensions the reverse conveying belt, and when the forward-reverse switching link drives the forward tensioning wheel and the reverse tensioning wheel to rotate forward, the forward tensioning wheel tensions the forward conveying belt.

[0013] In the above-mentioned transmission system of a combine harvester, the forward and reverse switching connecting rod includes a connecting rod shaft which is laterally arranged and rotatably connected to a connecting rod bracket, the connecting rod bracket is fixedly connected to the frame of the combine harvester, and the two ends of the connecting rod shaft are respectively provided with a forward crank and a reverse crank extending in different directions, the forward crank and the reverse crank are respectively hinged with a forward driving rod and a reverse driving rod, the forward driving rod is connected to a forward tensioning wheel, and the reverse driving rod is connected to a reverse tensioning wheel, and a connecting rod driving handle for driving the rotation thereof is fixed to the connecting rod shaft; the connecting rod bracket can be connected to any frame of the combine harvester, such as a frame of a conveying mechanism and a frame of a threshing mechanism.

[0014] In the above-mentioned transmission system of a combine harvester, the forward tensioning wheel is rotatably connected to the forward tensioning mounting plate, the forward tensioning mounting plate is rotatably connected to the transmission box, the forward drive rod is hinged to the forward tensioning mounting plate and drives it to rotate; the reverse tensioning wheel is rotatably connected to the reverse tensioning mounting plate, the reverse tensioning mounting plate is rotatably connected to the transmission box, the reverse drive rod is hinged to the reverse tensioning mounting plate and drives it to rotate.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] 1. The present invention provides a new transmission system for a combine harvester, which uses a transmission shaft to drive a conveying mechanism to convey materials in a forward direction, and a hollow shaft to drive a conveying structure to convey materials in a reverse direction. The transmission shaft and the hollow shaft are driven by a bevel gear set to have opposite rotation directions. When working, the conveying direction is switched by a tensioning mechanism outside the transmission box. The present invention does not use any clutch structure, nor does it use a shift fork to shift gears or shafts. When working, the transmission system in the transmission box will not change. Therefore, the structure of the present invention is simpler and the transmission is more stable.

[0017] 2. The present invention switches the conveying direction by means of a forward and reverse switching connecting rod. When the forward and reverse switching connecting rod is rotated in different directions, one tensioning wheel can simultaneously tighten the corresponding transmission belt and the other tensioning wheel can loosen the corresponding transmission belt, thereby achieving the purpose of switching the conveying direction, and the operation is very convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a stereogram of the present invention;

[0019] Figure 2 It is a structural diagram of the reverse conveying state of the present invention;

[0020] Figure 3 is another structural diagram of the reverse conveying state of the present invention;

[0021] Figure 4 It is a structural diagram of the forward conveying state of the present invention;

[0022] Figure 5 It is another structural diagram of the forward conveying state of the present invention;

[0023] Figure 6 It is a stereoscopic diagram of the forward and reverse switching connecting rod of the present invention;

[0024] Figure 7 It is a three-dimensional diagram of the transmission box of the present invention;

[0025] Figure 8 yes Figure 7 Axial cross-sectional view of

[0026] 1. Drive wheel; 2. Conveying mechanism; 3. Threshing mechanism; 4. Transmission shaft; 5. Forward driving wheel; 6. Conveying driving shaft; 7. Forward conveying belt; 8. Hollow shaft; 9. Reverse driving wheel; 10. Reverse conveying belt; 11. Forward tensioning wheel; 12. Reverse tensioning wheel; 13. First bevel gear; 14. Second bevel gear; 15. Threshing driving shaft; 16. Third bevel gear; 17. Main power wheel; 18. Main power belt; 19. Fan driving wheel; 20. Fan driving belt; 21. Fan driving shaft; 22. Fan mechanism; 23. Bearing; 24. Reverse driving wheel bearing mounting seat; 25. Connecting rod bracket; 26. Connecting rod shaft; 27. Forward crank; 28. Reverse crank; 29. ​​Forward driving rod; 30. Reverse driving rod; 31. Connecting rod driving handle; 32. Forward tensioning mounting plate; 33. Reverse tensioning mounting plate. DETAILED DESCRIPTION

[0027] The present invention will be further described below with reference to specific embodiments of the present invention. Figure 1-8 :

[0028] A transmission system of a combine harvester includes a conveying mechanism 2, a threshing mechanism 3, a fan mechanism 22, a transmission box 1 and a conveying direction switching mechanism. Specifically, the structures of each mechanism are as follows:

[0029] The conveying mechanism 2 is used to convey the cut crop stems. After the crop stems are cut, they are conveyed from bottom to top by the conveying mechanism 2 to the threshing mechanism 3. The conveying mechanism 2 includes a conveying drive shaft 6, a conveying driven shaft and a conveying chain. When the conveying drive shaft 6 rotates forward or reversely, it drives the conveying chain to rotate forward or reversely, thereby driving the conveying mechanism 2 to convey forward or reversely.

[0030] The threshing mechanism 3 is used to remove grains from crop stems and then separate them. The threshing mechanism 3 is driven by a threshing drive shaft 15.

[0031] The fan mechanism 22 is arranged below the threshing mechanism 3, with its air outlet facing the bottom of the threshing mechanism 3. The fan mechanism 22 is used to assist the threshing mechanism 3 in separating grains and crop stems. The fan mechanism 22 is driven by a fan drive shaft 21.

[0032] Transmission box 1 is the power transmission source of each mechanism of the combine harvester. The transmission box 1 transmits power forward to drive the conveying mechanism 2, transmits power backward to drive the threshing mechanism 3, and transmits power downward to drive the fan mechanism 22. The transmission box 1 is provided with an engine-driven transmission shaft 4, and one end of the transmission shaft 4 is provided with a main power wheel 17, and the main power wheel 17 is connected to the engine through a main power belt 18, wherein:

[0033] The driving structure of the conveying mechanism 2 is: a forward driving wheel 5 is mounted on one end of the transmission shaft 4, and the forward driving wheel 5 is connected to the conveying driving shaft 6 through a forward conveying belt 7 and drives it to rotate forward; a hollow shaft 8 with a clearance fit is coaxially arranged on the other end of the transmission shaft 4, and the transmission shaft 4 and the hollow shaft 8 are connected through a bevel gear set and have opposite rotation directions; a reverse driving wheel 9 is mounted on the hollow shaft 8, and the reverse driving wheel 9 is connected to the conveying driving shaft 6 through a reverse conveying belt 10 and drives it to rotate in the reverse direction; preferably, the main power wheel 17 is located on the outside of the forward driving wheel 5 and is integrally formed with the forward driving wheel 5.

[0034] The driving structure of the threshing mechanism 3 is: the bevel gear set includes a first bevel gear 13 mounted on the transmission shaft 4, a second bevel gear 14 mounted on the hollow shaft 8, and a third bevel gear 16 mounted on the threshing drive shaft 15. The first bevel gear 13 and the second bevel gear 14 are simultaneously meshed with the third bevel gear 16 for transmission, and the intersection angle between the transmission shaft 4, the hollow shaft 8 and the threshing drive shaft 15 is 90°.

[0035] The driving structure of the fan mechanism 22 is: the other end of the transmission shaft 4 extends out of the hollow shaft 8 and is mounted with a fan driving wheel 19, the fan driving wheel 19 is located on the outside of the reverse driving wheel 9, the fan driving wheel 19 is connected to the fan driving shaft 21 through a fan driving belt 20, and the fan driving shaft 21 drives the fan mechanism 22 to work.

[0036] The conveying direction switching mechanism, the forward conveying belt 7 and the reverse conveying belt 10 are respectively provided with a forward tensioning wheel 11 and a reverse tensioning wheel 12, the forward tensioning wheel 11 and the reverse tensioning wheel 12 are respectively connected to the two ends of the forward and reverse switching connecting rod and the tensioning state is switched by the forward tensioning wheel 11: when the forward tensioning wheel 11 tensions the forward conveying belt 7, the conveying mechanism 2 conveys in the forward direction; when the reverse tensioning wheel 12 tensions the reverse conveying belt 10, the conveying mechanism 2 conveys in the reverse direction.

[0037] The transmission process of the reverse transmission in this embodiment is: Figure 2 and attached Figure 3, by operating the forward and reverse switching link, the reverse tensioning wheel 12 tensions the reverse conveying belt 10. At this time, the forward conveying belt 7 is in a relaxed state, and the reverse conveying belt 10 is in a tensioned state. The engine drives the main power wheel 17 to rotate through the main power belt 18, and the forward driving wheel 5 and the transmission shaft 4 rotate accordingly. However, since the forward conveying belt 7 is in a relaxed state, the forward driving wheel 5 cannot drive the forward conveying belt 7 to rotate synchronously, but will be in a slipping state. When the transmission shaft 4 rotates, the first bevel gear 13 mounted on the transmission shaft 4 rotates accordingly, and the first bevel gear 13 drives the third bevel gear 16 and the second bevel gear 14 to rotate in turn. When the third bevel gear 16 rotates, it outputs power to drive the threshing mechanism 3, and the second bevel gear 14 mounted on the hollow shaft 8 drives the hollow shaft 8 to rotate. Since the rotation directions of the first bevel gear 13 and the second bevel gear 14 are opposite, the rotation directions of the transmission shaft 4 and the hollow shaft 8 are also opposite. The hollow shaft 8 drives the reverse driving wheel 9 mounted on the hollow shaft 8 to rotate. Since the reverse conveying belt 10 is in a tensioned state, the reverse driving wheel 9 drives the conveying drive shaft 6 to rotate in the reverse direction through the reverse conveying belt 10, thereby achieving the purpose of reverse conveying.

[0038] The transmission process of the forward conveying in this embodiment is: Figure 4 and attached Figure 5 By operating the forward and reverse switching connecting rod, the forward tensioning wheel 11 tensions the forward conveying belt 7. At this time, the reverse conveying belt 10 is in a relaxed state, and the forward conveying belt 7 is in a tensioned state. The engine drives the main power wheel 17 to rotate through the main power belt 18, and the forward driving wheel 5 and the transmission shaft 4 rotate accordingly. Since the forward conveying belt 7 is in a tensioned state, the forward driving wheel 5 drives the conveying drive shaft 6 to rotate forward through the forward conveying belt 7, thereby achieving the purpose of forward conveying. When the transmission shaft 4 rotates, the first bevel gear 13 mounted on the transmission shaft 4 rotates accordingly, and the first bevel gear 13 drives the third bevel gear 16 and the second bevel gear 14 to rotate in turn. When the third bevel gear 16 rotates, it outputs power to drive the threshing mechanism 3, and the second bevel gear 14 mounted on the hollow shaft 8 drives the hollow shaft 8 to rotate. Since the rotation directions of the first bevel gear 13 and the second bevel gear 14 are opposite, the rotation directions of the transmission shaft 4 and the hollow shaft 8 are also opposite. The hollow shaft 8 drives the reverse driving wheel 9 mounted on the hollow shaft 8 to rotate. Since the reverse conveying belt 10 is in a relaxed state, the reverse driving wheel 5 cannot drive the reverse conveying belt 7 to rotate synchronously, but will be in a slipping state.

[0039] Compare with Figure 7 and attached Figure 8 The transmission shaft 4, hollow shaft 8, threshing transmission shaft 4 and transmission box 1 are all supported by a plurality of bearings 23. The reverse drive wheel 9 extends outwardly from a reverse drive wheel 9 bearing 23 mounting seat, and a bearing 23 is arranged between the reverse drive wheel 9 bearing 23 mounting seat and the transmission shaft 4.

[0040] The specific structure of this embodiment of switching the tensioning state by operating the forward and reverse switching connecting rod is:

[0041] The forward tensioning wheel 11 is arranged at the front side of the forward conveying belt 7, and the reverse tensioning wheel 12 is arranged at the rear side of the reverse conveying belt 10. The forward-reverse switching link drives the forward tensioning wheel 11 and the reverse tensioning wheel 12 to rotate in the same direction to switch the tensioning state. Specifically, when the forward-reverse switching link drives the forward tensioning wheel 11 and the reverse tensioning wheel 12 to rotate backward, the forward tensioning wheel 11 tensions the forward conveying belt 7, and the reverse tensioning wheel 12 and the reverse conveying belt 10 are out of the tensioning state; when the forward-reverse switching link drives the forward tensioning wheel 11 and the reverse tensioning wheel 12 to rotate forward, the reverse tensioning wheel 12 tensions the reverse conveying belt 10, and the forward tensioning wheel 11 and the forward conveying belt 7 are out of the tensioning state.

[0042] See attached pictures Figure 3 , Attachment Figure 5 and attached Figure 6 The forward and reverse switching connecting rod includes a connecting rod shaft 26 which is laterally arranged and rotatably connected to a connecting rod bracket 25. The connecting rod bracket 25 is fixedly connected to the frame of the combine harvester. The two ends of the connecting rod shaft 26 are respectively provided with a forward crank 27 and a reverse crank 28 extending in different directions. The forward crank 27 and the reverse crank 28 are respectively hinged with a forward driving rod 29 and a reverse driving rod 30. The forward driving rod 29 is connected to the forward tensioning wheel 11, and the reverse driving rod 30 is connected to the reverse tensioning wheel 12. A connecting rod driving handle 31 for driving the rotation thereof is fixed to the connecting rod shaft 26. The connecting rod bracket 25 can be connected to any frame of the combine harvester, such as the frame of the conveying mechanism 2 and the frame of the threshing mechanism 3.

[0043] Furthermore, the forward tensioning wheel 11 is rotatably connected to the forward tensioning mounting plate 32, the forward tensioning mounting plate 32 is rotatably connected to the transmission box 1, and the forward drive rod 29 is hinged to the forward tensioning mounting plate 32 and drives it to rotate; the reverse tensioning wheel 12 is rotatably connected to the reverse tensioning mounting plate 33, the reverse tensioning mounting plate 33 is rotatably connected to the transmission box 1, and the reverse drive rod 30 is hinged to the reverse tensioning mounting plate 33 and drives it to rotate.

[0044] By pulling the connecting rod driving handle 31, the connecting rod shaft 26 is driven to rotate. When the connecting rod shaft 26 rotates, one end of the connecting rod shaft 26 drives the forward tensioning mounting plate 32 to rotate around the transmission box 1 through the forward crank 27 and the forward driving rod 29, and the other end of the connecting rod shaft 26 drives the reverse tensioning mounting plate 33 to rotate around the transmission box 1 through the reverse crank 28 and the reverse driving rod 30. The forward tensioning mounting plate 32 is rotated to make the forward tensioning wheel 11 rotate forward or backward, and the reverse tensioning mounting plate 33 is rotated to make the reverse tensioning wheel 12 rotate forward or backward. After the adjustment is completed, the forward and reverse switching connecting rod can also be locked by a compression spring or other locking device.

[0045] The above embodiments are only preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Therefore, any equivalent changes made based on the structure, shape, and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A transmission system for a combine harvester, comprising a transmission box (1), a conveying mechanism (2) and a threshing mechanism (3), wherein the transmission box (1) transmits power forward to drive the conveying mechanism (3) and transmits power backward to drive the threshing mechanism (3), characterized in that: The transmission box (1) is provided with a transmission shaft (4) driven by an engine. One end of the transmission shaft (4) is provided with a forward driving wheel (5). The forward driving wheel (5) is connected to the conveying driving shaft (6) through a forward conveying belt (7) and drives the conveying driving shaft (6) to rotate in a forward direction. The other end of the transmission shaft (4) is coaxially provided with a hollow shaft (8) with a clearance fit. The transmission shaft (4) and the hollow shaft (8) are connected to each other through a bevel gear set and have opposite rotation directions. The hollow shaft (8) is provided with a reverse driving wheel (9). The reverse driving wheel (9) is connected to the conveying driving shaft (6) through a forward conveying belt (7). The shaft (6) is connected to the reverse conveying belt (10) and driven to rotate in the reverse direction. The forward conveying belt (7) and the reverse conveying belt (10) are respectively provided with a forward tensioning wheel (11) and a reverse tensioning wheel (12). The forward tensioning wheel (11) and the reverse tensioning wheel (12) are respectively connected to the two ends of the forward and reverse switching connecting rod and the tensioning state is switched by the forward tensioning wheel (11): when the forward tensioning wheel (11) tensions the forward conveying belt (7), the conveying mechanism (2) conveys in the forward direction; when the reverse tensioning wheel (12) tensions the reverse conveying belt (10), the conveying mechanism (2) conveys in the reverse direction.

2. The transmission system of a combine harvester according to claim 1, characterized in that: The bevel gear set comprises a first bevel gear (13) mounted on a transmission shaft (4), a second bevel gear (14) mounted on a hollow shaft (8), and a third bevel gear (16) mounted on a threshing drive shaft (15); the first bevel gear (13) and the second bevel gear (14) are simultaneously meshed with the third bevel gear (16) for transmission; and an intersection angle between the transmission shaft (4), the hollow shaft (8) and the threshing drive shaft (15) is 90°.

3. The transmission system of a combine harvester according to claim 1, characterized in that: One end of the transmission shaft (4) is provided with a main power wheel (17), the main power wheel (17) is connected to the engine through a main power belt (18), and the main power wheel (17) is located outside the forward drive wheel (5) and is integrally formed with the forward drive wheel (5).

4. The transmission system of a combine harvester according to claim 1, characterized in that: The other end of the transmission shaft (4) extends out of the hollow shaft (8) and is provided with a fan driving wheel (19), the fan driving wheel (19) is located outside the reverse driving wheel (9), the fan driving wheel (19) is connected to the fan driving shaft (21) through a fan driving belt (20), the fan driving shaft (21) drives a fan mechanism (22) to work, the fan mechanism (22) is arranged below the threshing mechanism (3), and its air outlet faces the bottom of the threshing mechanism (3).

5. The transmission system of a combine harvester according to claim 2, characterized in that: The transmission shaft (4), the hollow shaft (8), the threshing transmission shaft (15) and the transmission box (1) are all supported by a plurality of bearings (23); the reverse driving wheel (9) extends outwardly to form a reverse driving wheel bearing mounting seat (24); and a bearing (23) is provided between the reverse driving wheel bearing mounting seat (24) and the transmission shaft (4).

6. The transmission system of a combine harvester according to claim 1, characterized in that: The forward tensioning wheel (11) is arranged on the front side of the forward conveying belt (7), and the reverse tensioning wheel (12) is arranged on the rear side of the reverse conveying belt (11); or, the forward tensioning wheel (11) is arranged on the rear side of the forward conveying belt (7), and the reverse tensioning wheel (12) is arranged on the front side of the reverse conveying belt (11); the forward-reverse switching connecting rod drives the forward tensioning wheel (11) and the reverse tensioning wheel (12) to rotate in the same direction to switch the tensioning state.

7. The transmission system of a combine harvester according to claim 1, characterized in that: The forward and reverse switching connecting rod comprises a connecting rod shaft (26) which is transversely arranged and rotatably connected to a connecting rod bracket (25); the connecting rod bracket (25) is fixedly connected to the frame of the combine harvester; the two ends of the connecting rod shaft (26) are respectively provided with a forward crank (27) and a reverse crank (28) extending in different directions; the forward crank (27) and the reverse crank (28) are respectively hinged with a forward driving rod (29) and a reverse driving rod (30); the forward driving rod (29) is connected to a forward tensioning wheel (11), and the reverse driving rod (30) is connected to a reverse tensioning wheel (12); and a connecting rod driving handle (31) for driving the connecting rod shaft (26) to rotate is fixedly provided.

8. The transmission system of a combine harvester according to claim 7, characterized in that: The forward tensioning wheel (11) is rotatably connected to the forward tensioning mounting plate (32), the forward tensioning mounting plate (32) is rotatably connected to the transmission box (1), and the forward driving rod (29) is hinged to the forward tensioning mounting plate (32) and drives the forward tensioning mounting plate (32) to rotate; The reverse tensioning wheel (12) is rotatably connected to the reverse tensioning mounting plate (33), the reverse tensioning mounting plate (33) is rotatably connected to the transmission box (1), and the reverse driving rod (30) is hinged to the reverse tensioning mounting plate (33) and drives it to rotate.

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