Power transmission system and tractor

Abstract

The invention discloses a power transmission system and a tractor, the power transmission system comprises a power reversing device, a central transmission device, a main speed change device and an auxiliary speed change device, the central transmission device can transmit power to left and right wheels, and the main speed change device is provided with at least two main speed change gears; a main variable-speed input shaft of the main variable-speed device can receive power from the power reversing device and transmit the power to a main variable-speed output shaft, an auxiliary variable-speed driven shaft of the auxiliary variable-speed device is in meshing transmission with the main variable-speed output shaft, and a driving gear and a driven gear of the auxiliary variable-speed gear set are arranged on the auxiliary variable-speed driven shaft and the auxiliary variable-speed output shaft respectively. The first end of the auxiliary speed change output shaft is provided with a first shaft end gear body, the first shaft end gear body is in meshing transmission with the central transmission device, and the second end of the auxiliary speed change output shaft can be switched to be in butt joint transmission with the main speed change output shaft, so that the main speed change output shaft is directly connected with the central transmission device, and the effect of expanding the output rotating speed range can be achieved; and the purpose of wide application range is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of power transmission, and particularly relates to a power transmission system and a tractor. Background Art

[0002] As a core equipment in agricultural mechanized production, the power transmission system of a tractor needs to efficiently transmit the power output by the engine to the functional components of the drive wheels or working devices, which directly affects the traction performance, fuel economy and applicability to complex terrains of the tractor.

[0003] The output speed range of the power transmission system of traditional tractors is usually set according to typical tillage scenarios (such as plowing and rotary tillage). Although it can meet the basic farmland operation requirements, with the increasing demand for multi-functional operations in modern agriculture, the existing speed range can no longer meet the requirements, especially in the case of operating in complex terrains, resulting in limited application ranges. Summary of the Invention

[0004] Aiming at the above defects or deficiencies, the present invention provides a power transmission system and a tractor, aiming to solve the technical problem of the limited output speed range of the power transmission system of existing tractors.

[0005] To achieve the above object, in a first aspect of the present invention, a power transmission system is provided. The power transmission system includes a power reversing device, a central transmission device, a main speed change device and a sub-speed change device; the power reversing device can receive engine power and has forward gears and reverse gears; the central transmission device can transmit power to the left and right wheels; the main speed change device has at least two main speed change gears, and the main speed change input shaft of the main speed change device can receive power from the power reversing device and transmit it to the main speed change output shaft; the sub-speed change device includes a sub-speed change output shaft, a sub-speed change driven shaft and a sub-speed change gear set. The sub-speed change driven shaft is in meshing transmission with the main speed change output shaft. The driving gear and the driven gear of the sub-speed change gear set are respectively arranged on the sub-speed change driven shaft and the sub-speed change output shaft. A first shaft end gear body is provided at the first end of the sub-speed change output shaft, and the first shaft end gear body is in meshing transmission with the central transmission device. The second end of the sub-speed change output shaft can be switched to be in butt joint transmission with the main speed change output shaft, so that the main speed change output shaft is directly connected to the central transmission device.

[0006] In an embodiment of the present invention, a second shaft end gear body is provided at the first end of the main speed change output shaft, a third shaft end gear body meshing with the second shaft end gear body is provided at the first end of the sub-speed change driven shaft, and the number of teeth of the third shaft end gear body is greater than that of the second shaft end gear body. The number of the sub-speed change gear sets is at least two, and the speed ratios of the at least two sub-speed change gear sets are set to be different and both greater than 1.

[0007] In an embodiment of the present invention, the auxiliary speed change device has a first auxiliary speed change gear position, a second auxiliary speed change gear position, and a third auxiliary speed change gear position. The first auxiliary speed change gear position is set such that the second end of the auxiliary speed change output shaft is in butt joint transmission with the main speed change output shaft. The second auxiliary speed change gear position is set to perform two-stage deceleration successively through a second shaft end gear body, a third shaft end gear body, and one of the auxiliary speed change gear sets. The third auxiliary speed change gear position is set to perform two-stage deceleration successively through the second shaft end gear body, the third shaft end gear body, and another auxiliary speed change gear set. And the speed ratio of the second auxiliary speed change gear position is set to be 2 - 2.4, and the speed ratio of the third auxiliary speed change gear position is set to be 4.2 - 4.8.

[0008] In an embodiment of the present invention, the speed ratio of the second auxiliary speed change gear position is set to be 2.19.

[0009] In an embodiment of the present invention, the speed ratio of the third auxiliary speed change gear position is set to be 4.6.

[0010] In an embodiment of the present invention, the number of teeth of the second shaft end gear body is set to be 18, the number of teeth of the third shaft end gear body is set to be 34, the number of teeth of the mid-range driving gear in the auxiliary speed change gear set of the second auxiliary speed change gear position is set to be 25, and the number of teeth of the mid-range driven gear is set to be 29. The number of teeth of the low-range driving gear in the auxiliary speed change gear set of the third auxiliary speed change gear position is set to be 16, and the number of teeth of the low-range driven gear is set to be 39.

[0011] In an embodiment of the present invention, a constantly meshing driving gear is provided on the reversing output shaft of the power reversing device, and a fourth shaft end gear body meshing with the constantly meshing driving gear is provided at the first end of the main speed change input shaft. And the speed ratio of the forward gear set of the power reversing device is set to be 0.75 - 0.8, and the product of the speed ratio of the forward gear set and the speed ratio between the constantly meshing driving gear and the fourth shaft end gear body is set to be 0.98 - 1.0.

[0012] In an embodiment of the present invention, the speed ratio of the forward gear set is set to be 0.77.

[0013] In an embodiment of the present invention, the speed ratio between the constantly meshing driving gear and the fourth shaft end gear body is set to be 1.296.

[0014] In an embodiment of the present invention, the number of teeth of the forward driving gear in the forward gear set is set to be 35, and the number of teeth of the forward driven gear is set to be 27.

[0015] In an embodiment of the present invention, the number of teeth of the constantly meshing driving gear is set to be 27, and the number of teeth of the fourth shaft end gear body is set to be 35.

[0016] In an embodiment of the present invention, the main speed change device has a first main speed change gear position, a second main speed change gear position, a third main speed change gear position, and a fourth main speed change gear position. The speed ratio of the first main speed change gear position is set to 1.7 - 1.8, the speed ratio of the second main speed change gear position is set to 1.2 - 1.3, the speed ratio of the third main speed change gear position is set to 1.07 - 1.12, and the speed ratio of the fourth main speed change gear position is set to 0.7 - 0.9.

[0017] In an embodiment of the present invention, the number of teeth of the first gear driving gear in the first main speed change gear position is set to 17, and the number of teeth of the first gear driven gear is set to 30. The speed ratio of the first main speed change gear position is set to 1.76.

[0018] In an embodiment of the present invention, the number of teeth of the second gear driving gear in the second main speed change gear position is set to 20, and the number of teeth of the second gear driven gear is set to 25. The speed ratio of the second main speed change gear position is set to 1.25.

[0019] In an embodiment of the present invention, the number of teeth of the third gear driving gear in the third main speed change gear position is set to 21, and the number of teeth of the third gear driven gear is set to 23. The speed ratio of the third main speed change gear position is set to 1.095.

[0020] In an embodiment of the present invention, the number of teeth of the fourth gear driving gear in the fourth main speed change gear position is set to 25, and the number of teeth of the fourth gear driven gear is set to 20. The speed ratio of the fourth main speed change gear position is set to 0.8.

[0021] In an embodiment of the present invention, a first engaging device is provided at the second end of the auxiliary speed change output shaft. The first engaging device can be switched between connecting the auxiliary speed change output shaft and the main speed change output shaft and disconnecting the auxiliary speed change output shaft and the main speed change output shaft. The driving gear in the auxiliary speed change gear set close to the first engaging device is integrally provided with the auxiliary speed change driven shaft, and the driven gear in the auxiliary speed change gear set close to the first engaging device can be connected or disconnected from the auxiliary speed change output shaft through the first engaging device.

[0022] In an embodiment of the present invention, a second engaging device is further provided on the auxiliary speed change driven shaft. The second engaging device can be switched between connecting with the driving gear of the auxiliary speed change gear set and disconnecting from the driving gear of the auxiliary speed change gear set.

[0023] In an embodiment of the present invention, the first shaft end gear body is a bevel gear body, and the central transmission device has a large bevel gear meshing with the bevel gear body; wherein, the speed ratio between the bevel gear body and the large bevel gear is set to 4.0 - 4.5, or, the speed ratio between the bevel gear body and the large bevel gear is set to 4.2, or, the number of teeth of the bevel gear body is set to 10, and the number of teeth of the large bevel gear is set to 42.

[0024] In an embodiment of the present invention, the power transmission system further includes a wheel transmission device that receives power from the central transmission device. The wheel transmission device includes a wheel half shaft and a planetary gear ring, and the speed ratio between the half shaft gear body of the wheel half shaft and the planetary gear ring is set to be 5.4 - 5.6.

[0025] In an embodiment of the present invention, the power transmission system further includes a transfer device. The transfer device is provided with a transfer driven gear that meshes with the driven gear of the auxiliary speed change gear set, and the speed ratio between the driven gear of the auxiliary speed change gear set and the transfer driven gear is set to be greater than 1.

[0026] In an embodiment of the present invention, the number of teeth of the wheel half shaft is set to 14, and the number of teeth of the planetary gear ring is set to 63.

[0027] In an embodiment of the present invention, the speed ratio between the wheel half shaft and the planetary gear ring is set to 5.57.

[0028] In an embodiment of the present invention, the mid - range driven gear in the auxiliary speed change gear set meshes with the transfer driven gear. Among them, the number of teeth of the mid - range driven gear is set to 29, the number of teeth of the transfer driven gear is set to 34, or the speed ratio between the mid - range driven gear and the transfer driven gear is set to 1.17.

[0029] To achieve the above object, a second aspect of the present invention provides a tractor, wherein the tractor includes the power transmission system described above.

[0030] Through the above - mentioned technical solution, the power transmission system provided by the present invention has the following beneficial effects:

[0031] When the tractor uses the above - mentioned power transmission system, the power steering device can transmit the engine power to the main transmission input shaft of the main transmission device. The main transmission input shaft can transmit the power to the auxiliary transmission device. The auxiliary transmission device can transmit the power to the central transmission device through the auxiliary transmission output shaft. The central transmission device can transmit the power to the left and right wheels. The main transmission device has at least two main transmission gears, and the auxiliary transmission driven shaft of the auxiliary transmission device meshes with the main transmission output shaft and can transmit the power from the auxiliary transmission driven shaft to the auxiliary transmission output shaft through the auxiliary speed change gear set to play a role in expanding the output speed range. In addition, the auxiliary transmission device can also be switched to the auxiliary transmission output shaft to be directly connected to the main transmission output shaft for transmission, so that the main transmission output shaft is directly connected to the central transmission device. At this time, the auxiliary transmission device can be in the high - speed gear, thereby further playing a role in expanding the output speed range and achieving the purpose of wide application range.

[0032] Other features and advantages of the present invention will be described in detail in the subsequent specific implementation part. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings are used to provide a further understanding of the embodiments of the present invention, and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the embodiments of the present invention, but do not constitute a limitation to the embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on the structures shown in these drawings. In the drawings:

[0034] Figure 1 is a schematic structural diagram of a power transmission system according to an embodiment of the present invention;

[0035] Figure 2 is a schematic structural diagram of a power reversing device according to an embodiment of the present invention;

[0036] Figure 3 is a schematic structural diagram of a main speed change device and a sub-speed change device according to an embodiment of the present invention;

[0037] Figure 4 is a schematic structural diagram of a wheel transmission device according to an embodiment of the present invention;

[0038] Figure 5 is a schematic structural diagram of a power take-off device according to an embodiment of the present invention.

[0039] Explanation of reference numerals:

[0040] 100 Power reversing device 110 Reversing output shaft

[0041] 111 Constant-mesh driving gear

[0042] 120 Forward gear driving gear 121 Forward gear driven gear

[0043] 130 Reverse gear driving gear 131 Reverse gear driven gear

[0044] 140 Third engaging device

[0045] 200 Central transmission device 201 Large bevel gear

[0046] 300 Main speed change device 310 Main speed change input shaft

[0047] 311 Fourth shaft end gear body

[0048] 320 Main speed change output shaft 321 Second shaft end gear body

[0049] 330 First gear driving gear 331 First gear driven gear

[0050] 340 Second gear driving gear 341 Second gear driven gear

[0051] 350 Third gear driving gear 351 Third gear driven gear

[0052] 360 Fourth gear driving gear 361 Fourth gear driven gear

[0053] 370 Fourth engaging device

[0054] 400 Auxiliary transmission 410 Auxiliary transmission output shaft

[0055] 411 First shaft end gear body

[0056] 420 Auxiliary transmission driven shaft 421 Third shaft end gear body

[0057] 430 Medium gear driving gear 431 Medium gear driven gear

[0058] 440 Low gear driving gear 441 Low gear driven gear

[0059] 450 First engaging device 460 Second engaging device

[0060] 500 Wheel drive 510 Wheel half shaft

[0061] 520 Ring gear of planetary gear

[0062] 600 Power take-off 610 Power take-off driven gear

[0063] 611 Intermediate gear

[0064] 700 Transmission case 800 PTO shaft 800 Detailed implementation manners

[0065] The following describes in detail the specific embodiments of the present invention with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0066] The power transmission system and tractor of the present invention will be described below with reference to the accompanying drawings.

[0067] As Figure 1 and Figure 3 shown, the present invention provides a power transmission system, wherein the power transmission system includes:

[0068] A power reversing device 100, which can receive engine power and has forward and reverse gears;

[0069] A central transmission device 200, which can transmit power to the left and right wheels;

[0070] The main transmission device 300 has at least two main transmission gears, and the main transmission input shaft 310 of the main transmission device 300 can receive power from the power shift device 100 and transmit it to the main transmission output shaft 320;

[0071] The auxiliary transmission device 400 includes an auxiliary transmission output shaft 410, an auxiliary transmission driven shaft 420, and an auxiliary transmission gear set. The auxiliary transmission driven shaft 420 is in meshing transmission with the main transmission output shaft 320. The driving gear and the driven gear of the auxiliary transmission gear set are respectively arranged on the auxiliary transmission driven shaft 420 and the auxiliary transmission output shaft 410. A first shaft-end gear body 411 is provided at the first end of the auxiliary transmission output shaft 410, and the first shaft-end gear body 411 is in meshing transmission with the central transmission device 200. The second end of the auxiliary transmission output shaft 410 can be switched to be in butt joint transmission with the main transmission output shaft 320, so that the main transmission output shaft 320 is directly connected to the central transmission device 200.

[0072] When the tractor uses the above power transmission system, the power steering device can transmit the engine power to the main transmission input shaft 310 of the main transmission device 300. The main transmission input shaft 310 can transmit the power to the auxiliary transmission device 400. The auxiliary transmission device 400 can transmit the power to the central transmission device 200 through the auxiliary transmission output shaft 410. The central transmission device 200 can transmit the power to the left and right wheels. The main transmission device 300 has at least two main transmission gears, and the auxiliary transmission driven shaft 420 of the auxiliary transmission device 400 is in meshing transmission with the main transmission output shaft 320, and can transmit the power from the auxiliary transmission driven shaft 420 to the auxiliary transmission output shaft 410 through the auxiliary transmission gear set, so as to play a role in expanding the output speed range. In addition, the auxiliary transmission device 400 can also be switched to the butt joint transmission between the auxiliary transmission output shaft 410 and the main transmission output shaft 320, so that the main transmission output shaft 320 is directly connected to the central transmission device 200. At this time, the auxiliary transmission device 400 can be in the high gear, so as to further play a role in expanding the output speed range and achieve the purpose of wide application range. It should be particularly noted that the power transmission system provided by the present invention is particularly suitable for tractors. However, if other vehicles use the power transmission system in the present invention, it should fall within the protection scope of the present invention.

[0073] Specifically, refer to Figure 1 and Figure 2The power transmission system also includes a transmission case 700 and a PTO (Power Take Off) shaft 800. The PTO shaft 800 is rotatably arranged in the transmission case 700 and can output the power of the generator. The power reversing device 100 can be set as a shuttle reversing device, and includes a forward gear driving gear 120, a forward gear driven gear 121, a reverse gear driving gear 130, a reverse gear driven gear 131 and a reversing output shaft 110. The reversing output shaft 110 is rotatably arranged in the transmission case 700 and is arranged in parallel with the PTO shaft 800 at intervals. The forward gear driving gear 120 and the reverse gear driving gear 130 are sleeved on the PTO shaft 800 at intervals. The forward gear driven gear 121 and the reverse gear driven gear 131 are sleeved on the reversing output shaft 110. The forward gear driving gear 120 is constantly meshed with the forward gear driven gear 121. The reverse gear driving gear 130 and the reverse gear driven gear 131 are both in contact with the idle gear. The wheels are always meshed, and a third engaging device 140 may be provided on the PTO shaft 800 between the forward gear driving gear 120 and the reverse gear driving gear 130. The third engaging device 140 is configured to select one of the forward gear driving gear 120 and the reverse gear driving gear 130 for connection, and disconnect from the other. When the third engaging device 140 is switched to be connected to the forward gear driving gear 120 and disconnected from the reverse gear driving gear 130, the power reversing device 100 is in the forward gear; when the third engaging device 140 is switched to be connected to the reverse gear driving gear 130 and disconnected from the forward gear driving gear 120, the power reversing device 100 is in the reverse gear.

[0074] Furthermore, if Figure 3 As shown, the main speed input shaft 310 of the main speed change device 300 can be set as a hollow shaft and can be rotatably sleeved on the outer side of the PTO shaft 800, the reversing output shaft 110 of the power reversing device 100 is provided with a constant meshing driving gear 111, and the first end of the main speed input shaft 310 is provided with a fourth shaft end gear body 311 meshing with the constant meshing driving gear 111, that is, the main speed input shaft 310 can be coaxially arranged with the PTO shaft 800, and staggered with the reversing output shaft 110. At the same time, the main speed output shaft 320 of the main speed change device 300 is rotatably arranged in the transmission box 700, and is coaxially arranged with the reversing output shaft 110. Furthermore, at least two main speed gears of the main speed change device 300 can be realized by arranging at least two main speed gear sets in a one-to-one correspondence, wherein the driving gears of the main speed change gear sets are arranged on the main speed change input shaft 310, and the driven gears of the main speed change gear sets are arranged on the main speed change output shaft 320, and the driving gears and the driven gears in each main speed change gear set are arranged in a constant meshing manner, and a fourth engagement device 370 can be arranged on the main speed change input shaft 310 between the driving gears of two adjacent main speed change gear sets, so as to select the driving gear of one of the main speed change gear sets to be connected through the fourth engagement device 370.

[0075] In addition, the secondary transmission output shaft 410 of the secondary transmission device 400 is coaxially arranged with the main transmission output shaft 320. The secondary transmission driven shaft 420 is a hollow shaft and is rotatably sleeved outside the PTO shaft 800, that is, the secondary transmission driven shaft 420 is coaxially arranged with the PTO shaft 800.

[0076] Please refer to again Figure 1 and Figure 3 , in an embodiment of the present invention, a second shaft end gear body 321 is provided at the first end of the main transmission output shaft 320, and a third shaft end gear body 421 meshing with the second shaft end gear body 321 is provided at the first end of the secondary transmission driven shaft 420. And the number of teeth of the third shaft end gear body 421 is greater than that of the second shaft end gear body 321. The number of secondary transmission gear sets is at least two, and the speed ratios of at least two secondary transmission gear sets are set to be different and both greater than 1. That is, in addition to directly connecting the main transmission output shaft 320 with the central transmission device 200 through the secondary transmission output shaft 410 so that the secondary transmission device 400 has a high gear, at least two secondary transmission gear sets can also be provided so that the secondary transmission device 400 also has a low gear and a medium gear. At the same time, the low gear and the medium gear of the secondary transmission device 400 can not only be decelerated by the corresponding secondary transmission gear sets, but also be decelerated by the meshing of the second shaft end gear body 321 and the third shaft end gear body 421 before the secondary transmission gear sets. That is, the low gear and the medium gear of the secondary transmission device 400 are both decelerated in two stages, so as to flexibly match the rotational speed requirements and achieve a wider speed ratio coverage within a limited space, taking into account low-speed high torque and high-speed high efficiency. It should be particularly noted that the speed ratios mentioned in the present invention are obtained by dividing the number of teeth of the driven gear in the meshing gear set by the number of teeth of the driving gear.

[0077] In an embodiment of the present invention, the secondary transmission device 400 has a first secondary transmission gear position, a second secondary transmission gear position and a third secondary transmission gear position. The first secondary transmission gear position is set such that the second end of the secondary transmission output shaft 410 is in butt joint transmission with the main transmission output shaft 320, that is, the first secondary transmission gear position is set as a high gear. The second secondary transmission gear position is set to be decelerated in two stages through the second shaft end gear body 321, the third shaft end gear body 421 and one of the secondary transmission gear sets in sequence. The third secondary transmission gear position is set to be decelerated in two stages through the second shaft end gear body 321, the third shaft end gear body 421 and another secondary transmission gear set in sequence. And the speed ratio of the second secondary transmission gear position is set to be 2-2.4, that is, the second secondary transmission gear position is set as a medium gear. The speed ratio of the third secondary transmission gear position is set to be 4.2-4.8, that is, the third secondary transmission gear position is set as a low gear. By respectively limiting the ranges of the speed ratios of the second secondary transmission gear position and the third secondary transmission gear position, different operating requirements can be matched.

[0078] In an embodiment of the present invention, the speed ratio of the second auxiliary transmission gear position is set to 2.19, and / or the speed ratio of the third auxiliary transmission gear position is set to 4.6. The limitation of the specific speed ratio values of the second auxiliary transmission gear position and the third auxiliary transmission gear position is to find the best balance among power output, fuel efficiency, driving scenarios, and mechanical protection, ensuring that the tractor can operate efficiently and stably under different working conditions.

[0079] In an embodiment of the present invention, the number of teeth of the second shaft-end gear body 321 is set to 18, and the number of teeth of the third shaft-end gear body 421 is set to 34, that is, the speed ratio between the second shaft-end gear body 321 and the third shaft-end gear body 421 is 1.89. The number of teeth of the intermediate-speed driving gear 430 in the auxiliary transmission gear set of the second auxiliary transmission gear position is set to 25, and the number of teeth of the intermediate-speed driven gear 431 is set to 29, that is, the speed ratio of the auxiliary transmission gear set of the second auxiliary transmission gear position is 1.16, so that the speed ratio of the second auxiliary transmission gear position is 2.19; the number of teeth of the low-speed driving gear 440 in the auxiliary transmission gear set of the third auxiliary transmission gear position is set to 16, and the number of teeth of the low-speed driven gear 441 is set to 39, that is, the speed ratio of the auxiliary transmission gear set of the third auxiliary transmission gear position is 2.4375, so that the speed ratio of the third auxiliary transmission gear position is 4.6. By directly limiting the number of teeth of each gear structure, on the basis of ensuring the limited speed ratio, the space occupied by each gear can be balanced to achieve a compact layout.

[0080] See Figure 1 and Figure 2 In an embodiment of the present invention, a constantly meshing driving gear 111 is provided on the reversing output shaft 110 of the power reversing device 100, a fourth shaft-end gear body 311 meshing with the constantly meshing driving gear 111 is provided at the first end of the main transmission input shaft 310, and the speed ratio of the forward gear set of the power reversing device 100 is set to 0.75 - 0.8, and the product of the speed ratio of the forward gear set and the speed ratio between the constantly meshing driving gear 111 and the fourth shaft-end gear body 311 is set to 0.98 - 1.0. Limiting the speed ratio of the forward gear set of the power reversing device 100 and the product of the speed ratio between the constantly meshing driving gear 111 and the fourth shaft-end gear body 311 to be close to 1 can facilitate subsequent deceleration design.

[0081] In an embodiment of the present invention, the speed ratio of the forward gear set is set to 0.77, and / or the speed ratio of the reverse gear set of the power reversing device 100 is set to 0.85, and / or the speed ratio between the constantly meshing driving gear 111 and the fourth shaft-end gear body 311 is set to 1.296. The limitation of the specific speed ratio values is to find the best balance among power output, fuel efficiency, driving scenarios, and mechanical protection, ensuring that the tractor can operate efficiently and stably under different working conditions.

[0082] In an embodiment of the present invention, the number of teeth of the forward drive gear 120 in the forward gear set is set to 35, and the number of teeth of the forward driven gear 121 is set to 27; and / or, the number of teeth of the reverse drive gear 130 in the reverse gear set is set to 34, and the number of teeth of the reverse driven gear 131 is set to 29; and / or, the number of teeth of the constantly meshing drive gear 111 is set to 27, and the number of teeth of the fourth shaft end gear body 311 is set to 35. By directly limiting the number of teeth of each gear structure, on the basis of ensuring the limited speed ratio, the space occupied by each gear is balanced, and a compact layout is achieved.

[0083] In an embodiment of the present invention, the main transmission device 300 has a first main transmission gear position, a second main transmission gear position, a third main transmission gear position, and a fourth main transmission gear position, and the speed ratio of the first main transmission gear position is set to 1.7 - 1.8, the speed ratio of the second main transmission gear position is set to 1.2 - 1.3, the speed ratio of the third main transmission gear position is set to 1.07 - 1.12, and the speed ratio of the fourth main transmission gear position is set to 0.7 - 0.9. That is, the main transmission device 300 has four main transmission gear positions, realizing multiple gear position subdivisions to adapt to different operation scenarios.

[0084] As Figure 3 shown, in an embodiment of the present invention, the number of teeth of the first gear drive gear 330 in the first main transmission gear position is set to 17, and the number of teeth of the first gear driven gear 331 is set to 30, and the speed ratio of the first main transmission gear position is set to 1.76; and / or, the number of teeth of the second gear drive gear 340 in the second main transmission gear position is set to 20, and the number of teeth of the second gear driven gear 341 is set to 25, and the speed ratio of the second main transmission gear position is set to 1.25; and / or, the number of teeth of the third gear drive gear 350 in the third main transmission gear position is set to 21, and the number of teeth of the third gear driven gear 351 is set to 23, and the speed ratio of the third main transmission gear position is set to 1.095; and / or, the number of teeth of the fourth gear drive gear 360 in the fourth main transmission gear position is set to 25, and the number of teeth of the fourth gear driven gear 361 is set to 20, and the speed ratio of the fourth main transmission gear position is set to 0.8. By directly limiting the number of teeth of each gear structure, on the basis of ensuring the limited speed ratio, the space occupied by each gear is balanced, and a compact layout is achieved.

[0085] Specifically, the first gear drive gear 330, the second gear drive gear 340, the third gear drive gear 350, and the fourth gear drive gear 360 are sequentially and spacedly sleeved on the main transmission input shaft 310. The number of the fourth engaging devices 370 on the main transmission input shaft 310 is two. One of the fourth engaging devices 370 is located between the first gear drive gear 330 and the second gear drive gear 340, and the other fourth engaging device 370 is located between the third gear drive gear 350 and the fourth gear drive gear 360.

[0086] In an embodiment of the present invention, a first engaging device 450 is provided at the second end of the auxiliary transmission output shaft 410. The first engaging device 450 can be switched between connecting the auxiliary transmission output shaft 410 and the main transmission output shaft 320 and disconnecting the auxiliary transmission output shaft 410 and the main transmission output shaft 320. Then, by adding the first engaging device 450, it is possible to control the first engaging device 450 according to the required gear position of the tractor. In the case of needing to switch to the high gear of the auxiliary transmission device 400, control the first engaging device 450 to switch to connect the auxiliary transmission output shaft 410 and the main transmission output shaft 320, so as to directly connect the main transmission output shaft 320 and the central transmission device 200 through the auxiliary transmission output shaft 410. At the same time, the driving gear (for example: low gear driving gear 440) in the auxiliary transmission gear set disposed close to the first engaging device 450 is provided to be integrally provided with the auxiliary transmission driven shaft 420. The driven gear in the auxiliary transmission gear set disposed close to the first engaging device 450 can be connected or disconnected from the auxiliary transmission output shaft 410 through the first engaging device 450. That is, in addition to connecting the auxiliary transmission output shaft 410 and the main transmission output shaft 320, the first engaging device 450 can also connect the driven gear in the auxiliary transmission gear set. And setting the driving gear in the auxiliary transmission gear set and the auxiliary transmission driven shaft 420 as an integral structure can make the number of teeth of the gear relatively small and ensure the strength of the gear structure. Specifically, the number of teeth of the low gear driving gear 440 is set to 19.

[0087] In an embodiment of the present invention, a second engaging device 460 is further provided on the auxiliary transmission driven shaft 420. The second engaging device 460 can be switched between connecting with the driving gear of the auxiliary transmission gear set and disconnecting from the driving gear of the auxiliary transmission gear set. Specifically, the number of driving gears on the auxiliary transmission driven shaft 420 can be set to at least two. Then, by providing the second engaging device 460 between the two driving gears, one of the driving gears can be selectively connected through the second engaging device 460. More specifically, the driving gears on the auxiliary transmission driven shaft 420 can be the low gear driving gear 440 and the medium gear driving gear 430. And the low gear driving gear 440 is integrally provided with the auxiliary transmission driven shaft 420, the medium gear driving gear 430 is sleeved on the auxiliary transmission driven shaft 420, the second engaging device 460 is only used for the medium gear position, and the second engaging device 460 can be disposed between the low gear driving gear 440 and the medium gear driving gear 430 to play a role of compact layout, while the first engaging device 450 can be used for the low gear position and the high gear position.

[0088] Further, when the auxiliary transmission device 400 is in the high gear position, the second engagement device 460 switches to disconnect from the intermediate gear driving gear 430, and the first engagement device 450 switches to connect the auxiliary transmission output shaft 410 and the main transmission output shaft 320 to directly connect the main transmission output shaft 320 and the central transmission device 200; when in the intermediate gear position, the second engagement device 460 switches to connect with the intermediate gear driving gear 430, and the first engagement device 450 switches to disconnect from both the main transmission output shaft 320 and the low gear driven gear 441; when in the low gear position, the second engagement device 460 switches to disconnect from the intermediate gear driving gear 430, and the first engagement device 450 switches to connect with the low gear driven gear 441.

[0089] In an embodiment of the present invention, the first shaft end gear body 411 is provided as a bevel gear body, and the central transmission device 200 has a large bevel gear 201 meshing and driving with the bevel gear body; wherein, the speed ratio between the bevel gear body and the large bevel gear 201 is set to 4.0 - 4.5. Specifically, the speed ratio between the bevel gear body and the large bevel gear 201 is set to 4.2, and / or, the number of teeth of the bevel gear body is set to 10, and the number of teeth of the large bevel gear 201 is set to 42. The limitation of the specific speed ratio value is to find the best balance among power output, fuel efficiency, driving scenarios, and mechanical protection to ensure that the tractor can operate efficiently and stably under different working conditions.

[0090] See Figure 1 and Figure 4 In an embodiment of the present invention, the power transmission system further includes a wheel transmission device 500 that receives power from the central transmission device 200. The wheel transmission device 500 includes a wheel half shaft 510 and a planetary gear ring 520; wherein, the speed ratio between the half shaft gear body of the wheel half shaft 510 and the planetary gear ring 520 is set to 5.4 - 5.6. Specifically, the speed ratio between the half shaft gear body of the wheel half shaft 510 and the planetary gear ring 520 is set to 5.57, and / or, the number of teeth of the half shaft gear body of the wheel half shaft 510 is set to 14, and the number of teeth of the planetary gear ring 520 is set to 63. More specifically, the combination of the wheel transmission device 500 and the central transmission device 200 is a differential structure, and the large bevel gear 201 of the central transmission device 200 is integrated on the differential housing.

[0091] See Figure 1 and Figure 5 In an embodiment of the present invention, the power transmission system further includes a power dividing device 600. The power dividing device 600 is provided with a power dividing driven gear 610 meshing and driving with the driven gear of the auxiliary transmission gear set, and the speed ratio between the driven gear of the auxiliary transmission gear set and the power dividing driven gear 610 is set to be greater than 1. By adding the power dividing device 600, the power transmitted by the engine can be reasonably distributed.

[0092] In an embodiment of the present invention, the intermediate-speed driven gear 431 in the auxiliary transmission gear set meshes with the power take-off driven gear 610. Among them, the number of teeth of the intermediate-speed driven gear 431 is set to 29, the number of teeth of the power take-off driven gear 610 is set to 34, and / or the speed ratio between the intermediate-speed driven gear 431 and the power take-off driven gear 610 is set to 1.17. Further, an intermediate gear 611 is provided between the intermediate-speed driven gear 431 and the power take-off driven gear 610 for meshing transmission.

[0093] Specifically, each engaging device mentioned in the present invention can be set as a synchronizer, a meshing gear sleeve, a sliding sleeve, a coupling, etc.

[0094] The power transmission system provided by the present invention has the following advantages:

[0095] 1. The power is transmitted sequentially through multiple drive shafts and meshing gears sleeved on the drive shafts, and multiple gear positions are achieved through multiple groups of meshing gears, enabling the driver to select appropriate output power according to the actual working conditions. The overall structure of the power transmission system provided by the present invention is relatively simple, and the power transmission is stable, effectively ensuring the power output. At the same time, the gear ratio is optimized and reasonably distributed, so that the vehicle has high working comfort, small impact, and high transmission efficiency.

[0096] 2. The adapted tractor can be a medium-sized tractor for both paddy and dry fields. The transmission system has a wide horsepower coverage (130 - 160 horsepower) and a wide range of applications.

[0097] 3. Adopting the transmission path of the forward gear of the power reversing device - the fourth main transmission gear position of the main transmission device - the high-speed gear of the auxiliary transmission device - the central transmission device - the wheel transmission device in the present invention, the vehicle can reach a maximum speed of 39.9 km / h, approaching the standard of the speed limit of 40 km / h.

[0098] In addition, the present invention also provides a tractor, wherein the tractor includes the power transmission system described above. Since the tractor adopts all the technical solutions of the above embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be elaborated here one by one.

[0099] In the description of the present invention, it should be understood that the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0100] In the present invention, unless otherwise clearly defined and limited, terms such as "installed", "connected", "connected to", "fixed", etc. shall be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection, an electrical connection, or capable of communicating with each other; it can be directly connected, or indirectly connected through an intermediate medium, and can be the communication inside two elements or the interaction relationship between two elements, unless otherwise clearly defined. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0101] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0102] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A power transmission system, characterized in that, Comprising: A power shift device (100) that can receive engine power and has forward and reverse gears; A central transmission device (200) that can transmit power to the left and right wheels; A main transmission device (300) having at least two main transmission gears, and a main transmission input shaft (310) of the main transmission device (300) can receive power from the power shift device (100) and transmit it to a main transmission output shaft (320); An auxiliary transmission device (400) includes an auxiliary transmission output shaft (410), an auxiliary transmission driven shaft (420), and an auxiliary transmission gear set. The auxiliary transmission driven shaft (420) is in meshing transmission with the main transmission output shaft (320). The driving gear and the driven gear of the auxiliary transmission gear set are respectively arranged on the auxiliary transmission driven shaft (420) and the auxiliary transmission output shaft (410). A first shaft end gear body (411) is provided at a first end of the auxiliary transmission output shaft (410), and the first shaft end gear body (411) is in meshing transmission with the central transmission device (200). A second end of the auxiliary transmission output shaft (410) can be switched to be in butt joint transmission with the main transmission output shaft (320) so that the main transmission output shaft (320) is directly connected to the central transmission device (200).

2. The power transmission system according to claim 1, wherein A second shaft end gear body (321) is provided at a first end of the main transmission output shaft (320), and a third shaft end gear body (421) meshing with the second shaft end gear body (321) is provided at a first end of the auxiliary transmission driven shaft (420), and the number of teeth of the third shaft end gear body (421) is greater than that of the second shaft end gear body (321). The number of the auxiliary transmission gear sets is at least two, and the speed ratios of at least two of the auxiliary transmission gear sets are set to be different and all greater than 1.

3. The power transmission system according to claim 2, wherein The auxiliary transmission device (400) has a first auxiliary transmission gear, a second auxiliary transmission gear, and a third auxiliary transmission gear. The first auxiliary transmission gear is set such that the second end of the auxiliary transmission output shaft (410) is in butt joint transmission with the main transmission output shaft (320). The second auxiliary transmission gear is set to perform two-stage deceleration successively through the second shaft end gear body (321), the third shaft end gear body (421), and one of the auxiliary transmission gear sets. The third auxiliary transmission gear is set to perform two-stage deceleration successively through the second shaft end gear body (321), the third shaft end gear body (421), and another auxiliary transmission gear set. And the speed ratio of the second auxiliary transmission gear is set to be 2 to 2.4, and the speed ratio of the third auxiliary transmission gear is set to be 4.2 to 4.

8.

4. The power transmission system according to claim 3, characterized in that, The speed ratio of the second auxiliary transmission gear is set to be 2.19; And / or, the speed ratio of the third auxiliary transmission gear is set to be 4.6; And / or, the number of teeth of the second shaft-end gear body (321) is set to 18, the number of teeth of the third shaft-end gear body (421) is set to 34, the number of teeth of the mid-range driving gear (430) in the secondary speed-changing gear set of the second secondary speed-changing gear position is set to 25, and the number of teeth of the mid-range driven gear (431) is set to 29. The number of teeth of the low-range driving gear (440) in the secondary speed-changing gear set of the third secondary speed-changing gear position is set to 16, and the number of teeth of the low-range driven gear (441) is set to 39.

5. The power transmission system according to claim 1, characterized in that, A constantly meshing driving gear (111) is provided on the reversing output shaft (110) of the power reversing device (100). A fourth shaft-end gear body (311) meshing with the constantly meshing driving gear (111) is provided at the first end of the main speed-changing input shaft (310). And the speed ratio of the forward gear set of the power reversing device (100) is set to 0.75 - 0.8, and the product of the speed ratio of the forward gear set and the speed ratio between the constantly meshing driving gear (111) and the fourth shaft-end gear body (311) is set to 0.98 - 1.

0.

6. The power transmission system according to claim 5, wherein, The speed ratio of the forward gear set is set to 0.77; And / or, the speed ratio between the constantly meshing driving gear (111) and the fourth shaft-end gear body (311) is set to 1.296; And / or, the number of teeth of the forward driving gear (120) in the forward gear set is set to 35, and the number of teeth of the forward driven gear (121) is set to 27; And / or, the number of teeth of the constantly meshing driving gear (111) is set to 27, and the number of teeth of the fourth shaft-end gear body (311) is set to 35.

7. The power transmission system according to any one of claims 1 to 6, characterized in that, The main speed-changing device (300) has a first main speed-changing gear position, a second main speed-changing gear position, a third main speed-changing gear position, and a fourth main speed-changing gear position. And the speed ratio of the first main speed-changing gear position is set to 1.7 - 1.8, the speed ratio of the second main speed-changing gear position is set to 1.2 - 1.3, the speed ratio of the third main speed-changing gear position is set to 1.07 - 1.12, and the speed ratio of the fourth main speed-changing gear position is set to 0.7 - 0.

9.

8. The power transmission system according to claim 7, wherein The number of teeth of the first-gear driving gear (330) in the first main speed-changing gear position is set to 17, and the number of teeth of the first-gear driven gear (331) is set to 30. The speed ratio of the first main speed-changing gear position is set to 1.76; And / or, the number of teeth of the second-gear driving gear (340) in the second main speed-changing gear position is set to 20, and the number of teeth of the second-gear driven gear (341) is set to 25. The speed ratio of the second main speed-changing gear position is set to 1.25; And / or, the number of teeth of the third-gear driving gear (350) in the third main speed-changing gear position is set to 21, and the number of teeth of the third-gear driven gear (351) is set to 23. The speed ratio of the third main speed-changing gear position is set to 1.095; And / or, the number of teeth of the fourth-gear driving gear (360) in the fourth main speed-changing gear position is set to 25, and the number of teeth of the fourth-gear driven gear (361) is set to 20. The speed ratio of the fourth main speed-changing gear position is set to 0.

8.

9. The power transmission system according to any one of claims 1 to 6, characterized in that, A first engaging device (450) is provided at the second end of the auxiliary transmission output shaft (410). The first engaging device (450) can be switched between connecting the auxiliary transmission output shaft (410) and the main transmission output shaft (320) and disconnecting the auxiliary transmission output shaft (410) and the main transmission output shaft (320). The driving gear in the auxiliary transmission gear set disposed near the first engaging device (450) is integrally provided with the auxiliary transmission driven shaft (420). The driven gear in the auxiliary transmission gear set disposed near the first engaging device (450) can be connected to or disconnected from the auxiliary transmission output shaft (410) through the first engaging device (450). And / or, a second engaging device (460) is further provided on the auxiliary transmission driven shaft (420). The second engaging device (460) can be switched between connecting with the driving gear of the auxiliary transmission gear set and disconnecting from the driving gear of the auxiliary transmission gear set. And / or, the first shaft end gear body (411) is a bevel gear body, and the central transmission device (200) has a large bevel gear (201) meshing with the bevel gear body. Wherein, the speed ratio between the bevel gear body and the large bevel gear (201) is set to be 4.0 - 4.5, or, the speed ratio between the bevel gear body and the large bevel gear (201) is set to be 4.2, or, the number of teeth of the bevel gear body is 10, and the number of teeth of the large bevel gear (201) is 42.

10. The power transmission system according to any one of claims 1 to 6, characterized in that, The power transmission system further includes a wheel transmission device (500) receiving power from the central transmission device (200). The wheel transmission device (500) includes a wheel half shaft (510) and a planetary gear ring (520). The speed ratio between the half shaft gear body of the wheel half shaft (510) and the planetary gear ring (520) is set to be 5.4 - 5.

6. The power transmission system further includes a transfer device (600). The transfer device (600) is provided with a transfer driven gear (610) meshing with the driven gear of the auxiliary transmission gear set. And the speed ratio between the driven gear of the auxiliary transmission gear set and the transfer driven gear (610) is set to be greater than 1.

11. The power transmission system according to claim 10, wherein, The number of teeth of the wheel half shaft (510) is 14, and the number of teeth of the planetary gear ring (520) is 63. And / or, the speed ratio between the wheel half shaft (510) and the planetary gear ring (520) is set to be 5.

57. And / or, the intermediate gear driven gear (431) in the auxiliary transmission gear set meshes with the transfer driven gear (610). Wherein, the number of teeth of the intermediate gear driven gear (431) is 29, and the number of teeth of the transfer driven gear (610) is 34, or, the speed ratio between the intermediate gear driven gear (431) and the transfer driven gear (610) is set to be 1.

17.

12. A tractor, characterized in that, The tractor includes the power transmission system according to any one of claims 1 to 11.

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