Power gear shifting transmission system of paddy field tractor

Abstract

The invention provides a paddy field tractor power gear shifting transmission system. The paddy field tractor power gear shifting transmission system comprises a power gear shifting mechanism; an input shaft of the main and auxiliary speed change mechanism is in transmission connection with the first output end of the power gear shifting mechanism, and an output shaft of the main and auxiliary speed change mechanism is in transmission connection with a central transmission mechanism; the input end of the PTO clutch is in transmission connection with the second output end of the power gear shifting mechanism; the input end of the PTO speed change mechanism is in transmission connection with the output end of the PTO clutch, and the output end of the PTO speed change mechanism is in transmission connection with a PTO output mechanism. Power is obtained from the second output end of the power gear shifting mechanism through the PTO clutch, and the space of the tractor in the length direction is saved; through the PTO speed change mechanism, the output rotating speed change capacity of the tractor PTO is improved, and the tractor PTO speed change mechanism can be suitable for various PTO operation modes.

Description

Technical Field

[0001] The invention relates to the technical field of tractor gearboxes, and in particular to a power shift transmission system for a paddy field tractor. Background Art

[0002] With the advancement of tractor technology, powershift has become a key technology sought by companies to enhance their competitiveness. The core of powershift technology is to achieve efficient transmission without interrupting power. This technology meets the demands of modern agriculture for efficiency, comfort, and intelligence, while also laying the foundation for the subsequent application of CVT and hybrid technologies. Consequently, the application prospects of tractor powershift transmission systems are attracting considerable attention.

[0003] Compared to traditional tractors operating in plowing mode, paddy field tractors use a PTO (Pulley Towing) mode, which is a common operating condition. This is especially true in paddy field environments, where rotary tillage operations require a variety of PTO speeds to accommodate different agricultural implements. Traditional tractor PTOs are located at the rear end of the rear axle housing. Due to axial space constraints around the main shaft, they are generally limited to two speeds or forward and reverse outputs. However, with the increasing demand for PTO forward, reverse, and synchronized power take-off (PTO) functions, the output modes of traditional tractor PTOs are becoming increasingly incapable of adapting to these diverse output requirements.

[0004] In addition, during paddy field operations, due to the small size of the land, the turning radius becomes an important indicator for judging the core competitiveness of the tractor. Therefore, the double-speed reversing function that can reduce the turning radius has become the direction for tractor companies to benchmark against international standards. Summary of the Invention

[0005] The technical problem to be solved by the present invention is: how to improve the output speed variation capability of the tractor PTO to meet the requirements of the PTO forward and reverse rotation and multiple power output functions.

[0006] The technical solution of the present invention to solve the above technical problems is as follows: The present invention provides a power shift transmission system for a paddy field tractor, comprising: A power shift mechanism, wherein the power shift mechanism is provided with a first output end and a second output end; A main and auxiliary speed change mechanism, wherein the input shaft of the main and auxiliary speed change mechanism is transmission-connected to the first output end of the power shift mechanism, and the output shaft of the main and auxiliary speed change mechanism is transmission-connected to the central transmission mechanism; A PTO clutch, wherein an input end of the PTO clutch is transmission-connected to the second output end of the power shift mechanism; The PTO speed change mechanism has an input end that is transmission-connected to the output end of the PTO clutch, and an output end that is transmission-connected to the PTO output mechanism.

[0007] The beneficial effects of the present invention are: By adopting the present invention, power is obtained from the second output end of the power shift mechanism through the PTO clutch, which saves space in the length direction of the tractor and provides space for arranging the PTO clutch and the PTO speed change mechanism; the output speed change capability of the tractor PTO is increased through the PTO speed change mechanism, and it can be applied to various PTO operation modes; in addition, power reversal and speed shifting are superimposed by the power shift mechanism and the main and auxiliary speed change mechanisms, so that multi-speed operation of the tractor in both forward and reverse directions can be achieved, thereby improving functionality.

[0008] On the basis of the above technical solution, the present invention can also be improved as follows.

[0009] Furthermore, the PTO speed change mechanism includes a PTO speed change shaft and a PTO multi-link gear. A plurality of PTO gear gears are movably sleeved on the PTO speed change shaft. Each PTO gear gear is respectively engaged with the PTO multi-link gear. One of the PTO gear gears is transmission-connected to the output end of the PTO clutch. A PTO synchronizer is provided on one side of the PTO gear. The PTO speed change shaft is the output end of the PTO speed change mechanism.

[0010] The PTO synchronizer can link any PTO gear with the PTO speed shaft; it obtains power from the output end of the PTO clutch through one of the PTO gear gears, and then transmits it to the PTO multi-gear. Different parts of the PTO multi-gear transmit power to the remaining PTO gear gears, so that each PTO gear has a different speed; thus, when any PTO gear gear is linked with the PTO speed shaft through the PTO synchronizer, the PTO speed shaft can obtain the corresponding speed, realizing multi-gear PTO output, increasing the output speed change capability of the tractor PTO, and being applicable to various PTO operation modes.

[0011] Furthermore, a power take-off shaft section is provided in the middle of one of the PTO gear gears which is transmission-connected to the output end of the PTO clutch. The power take-off shaft section extends into the output end of the PTO clutch and is transmission-connected. The power take-off shaft section is coaxially arranged with the PTO speed change shaft.

[0012] The power take-off shaft section and the output end of the PTO clutch can be driven by a spline, which is easy to install and improves the reliability of the transmission between the PTO clutch and the PTO gear gear.

[0013] Furthermore, every two PTO gears are arranged in pairs, and a PTO synchronizer is provided between the two PTO gears arranged in pairs.

[0014] The number of PTO synchronizers is saved, the structure is compact, and the cost is reduced.

[0015] Furthermore, the PTO multi-gear is movably sleeved on the output shaft of the primary and secondary speed change mechanisms.

[0016] The output shafts of the primary and secondary speed change mechanisms are used to provide installation space for the PTO multi-gears, eliminating the need to provide a separate shaft for the PTO multi-gears. This reduces the overall size and weight of the machine and facilitates lightweight design of the entire machine.

[0017] Furthermore, the PTO output mechanism includes a PTO driving gear and a PTO output shaft. The PTO driving gear is sleeved on the PTO speed change shaft. The PTO output shaft is sleeved with a PTO passive gear. The PTO passive gear is engaged with the PTO driving gear. The PTO output shaft is also provided with a composite oil seal special for paddy fields.

[0018] It has a compact structure, is easy to install and has good reliability. It is easy to adapt to paddy field operations through the special composite oil seal for paddy fields.

[0019] Furthermore, the power shift mechanism includes a power input shaft, a power output shaft and a reversing idler shaft, the power input shaft is provided with a reversing gear, a power low gear gear and a power high gear clutch, the power output shaft is provided with a reversing clutch, a power low gear clutch and a power high gear gear, the reversing clutch and the reversing gear are respectively engaged with the idler gear on the reversing idler shaft, the power low gear clutch is engaged with the power low gear gear, and the power high gear clutch is engaged with the power high gear gear; Among them, one end of the power output shaft is the first output end of the power shift mechanism, and one end of the power input shaft is the second output end of the power shift mechanism.

[0020] When the reversing clutch is closed, the power of the power input shaft is reversed by the reversing idler shaft and then transmitted to the power output shaft through the reversing clutch, realizing reverse gear; when the reversing clutch is disconnected, the high and low gear shifting is realized through the power high gear clutch and the power low gear clutch. Under the joint action of the main and auxiliary speed change mechanisms, the gear shifting capability is greatly increased, which can adapt to various road conditions and site operations.

[0021] Furthermore, the second output end of the power shift mechanism is also provided with a hydraulic output gear; and further comprises a hydraulic power take-off shaft, wherein the hydraulic power take-off shaft is connected to the hydraulic output gear via an idler gear transmission.

[0022] The hydraulic pump of the hydraulic system can obtain power through the hydraulic power take-off shaft, which enables the hydraulic pump to be installed on the transmission system. It can replace the solution of installing the hydraulic pump used for steering and lifting on the engine on traditional tractors, reducing the hydraulic pipelines in the engine compartment, making the pipeline layout simpler and the maintenance cost lower.

[0023] Furthermore, it also includes a front-drive mechanism, and a front-drive output gear is provided on the output shaft of the main and auxiliary speed change mechanisms, and the front-drive mechanism is transmission-connected to the front-drive output gear.

[0024] The front drive mechanism is used to connect the front axle assembly. When the front drive mechanism is working, the four-wheel drive mode can be realized, which reduces the turning radius of the tractor and improves the terrain adaptability.

[0025] Furthermore, the front-drive mechanism includes a front-drive speed change shaft and a front-drive output shaft, the front-drive speed change shaft is provided with a front-drive high-speed gear and a front-drive low-speed gear, the front-drive output shaft is provided with a front-drive high-speed clutch and a front-drive low-speed clutch, the front-drive high-speed clutch is engaged with the front-drive high-speed gear, the front-drive low-speed clutch is engaged with the front-drive low-speed gear; the front-drive low-speed gear is engaged with the front-drive output gear.

[0026] The front-wheel drive high-speed clutch and the front-wheel drive high-speed gear are used for double-speed transmission, so the front wheels can rotate faster when turning, completing the steering more quickly and reducing the turning radius; gear shifting is achieved through the wet clutch, which improves operating comfort.

[0027] Furthermore, a parking brake is provided on the output shaft of the main and auxiliary speed change mechanisms.

[0028] It is convenient to park after parking. By braking the output shafts of the main and auxiliary speed change mechanisms, there is no power input to the central transmission mechanism and the front drive mechanism, thus realizing the parking brake of the front and rear wheels.

[0029] Furthermore, the main and auxiliary speed change mechanisms include a main speed change shaft, an auxiliary speed change shaft and an intermediate shaft, the main speed change shaft is provided with a first main speed change gear pair, the auxiliary speed change shaft is provided with an auxiliary speed change gear pair, and the first main speed change gear pair and the auxiliary speed change gear pair are respectively connected to the intermediate shaft in a transmission manner; Among them, the main speed change shaft is the input shaft of the main and auxiliary speed change mechanisms; the auxiliary speed change shaft is the output shaft of the main and auxiliary speed change mechanisms.

[0030] Through the coordination of the three-axis main and auxiliary speed change, the total number of gears is at least twice that of the main speed change gears, which increases the number of gears and can match a variety of speed output capabilities.

[0031] Furthermore, the intermediate shaft is provided with a second speed change gear pair, which is transmission-connected to the main speed change shaft.

[0032] The first main speed gear pair and the second speed gear pair cooperate to achieve gear superposition and a compact structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a structural schematic diagram of the present invention.

[0034] In the accompanying drawings, the technical features represented by the reference numerals are as follows: 1-Power shift mechanism; 11-Power input shaft; 12-Power output shaft; 13-Reversing idler shaft; 14-Reversing gear; 15-Reversing clutch; 16-Power low gear; 17-Power high gear clutch; 18-Power low gear clutch; 19-Power high gear; 2-Main and auxiliary transmission mechanisms; 20-Parking brake; 21-Main transmission shaft; 22-Auxiliary transmission shaft; 23-Intermediate shaft; 24-Low gear; 25-Main transmission synchronizer; 26-Fixed gear; 3-Central transmission mechanism; 4-Final transmission mechanism; 5-PTO clutch; 6-PTO speed change mechanism; 61-PTO speed change shaft; 62-PTO gear; 63-PTO synchronizer; 64-PTO multi-gear; 7-PTO output mechanism; 71-PTO driving gear; 72-PTO driven gear; 73-PTO output shaft; 8-Hydraulic power take-off shaft; 81-Hydraulic output gear; 9-front drive mechanism; 91-front drive output gear; 92-front drive speed change shaft; 93-front drive output shaft; 94-front drive high-speed clutch; 95-front drive low-speed clutch. DETAILED DESCRIPTION

[0035] The principles and features of the present invention are described below. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0036] The present invention refers to Figure 1 .

[0037] The present invention provides a power shift transmission system for a paddy field tractor, comprising: A power shift mechanism 1, wherein the power shift mechanism 1 is provided with a first output end and a second output end; A main and auxiliary speed change mechanism 2, wherein the input shaft of the main and auxiliary speed change mechanism 2 is drivingly connected to the first output end of the power shift mechanism 1, and the output shaft of the main and auxiliary speed change mechanism 2 is drivingly connected to the central transmission mechanism 3; A PTO clutch 5, wherein an input end of the PTO clutch 5 is transmission-connected to a second output end of the power shift mechanism 1; The PTO speed change mechanism 6 has an input end drivingly connected to the output end of the PTO clutch 5 , and an output end of the PTO speed change mechanism 6 is drivingly connected to the PTO output mechanism 7 .

[0038] principle: During assembly, the central drive mechanism 3 is typically located within the rear axle housing of the tractor. The two output ends of the central drive mechanism 3 are each connected to a final drive mechanism 4, which is used to connect to the rear wheels. The central drive mechanism 3 and the final drive mechanism 4 are commonly referred to in the prior art (the final drive mechanism 4 is also called a half-axle assembly). The technical problem to be solved by the present invention does not involve the specific structures of these two mechanisms, so they will not be described in detail.

[0039] During operation, engine power is output to the power shift mechanism 1. By operating the power shift mechanism 1 to reverse power, the primary and secondary transmission mechanisms 2 are operated to perform multi-speed shifting. This allows the output shafts of the primary and secondary transmission mechanisms 2 to output multiple forward and reverse speeds to the central transmission mechanism 3, enabling multi-speed operation in both forward and reverse directions. The PTO clutch 5 draws power directly from the second output terminal of the power shift mechanism 1, eliminating the need for the PTO to draw power from the central transmission mechanism 3. This eliminates the need for the PTO assembly to be mounted on the rear axle housing, saving space along the tractor's length and allowing for the placement of the PTO clutch 5 and PTO transmission mechanism 6. By operating the PTO transmission mechanism 6 to perform multi-speed shifting, multiple speeds are provided for the PTO output mechanism 7, increasing the tractor's PTO's output speed variation capability and accommodating the PTO's forward and reverse rotation and various power output functions.

[0040] By adopting the present invention, power is obtained from the second output end of the power shift mechanism 1 through the PTO clutch 5, which saves space in the length direction of the tractor and provides space for arranging the PTO clutch 5 and the PTO speed change mechanism 6; the output speed change capability of the tractor PTO is increased through the PTO speed change mechanism 6, and it can be applied to various PTO operation modes; in addition, power reversing and speed shifting are superimposed by the power shift mechanism 1 and the main and auxiliary speed change mechanisms 2, so that multi-speed operation can be achieved in both forward and reverse directions of the tractor, thereby improving functionality.

[0041] Furthermore, the PTO speed change mechanism 6 includes a PTO speed change shaft 61 and a PTO multi-link gear 64. A plurality of PTO gear gears 62 are movably sleeved on the PTO speed change shaft 61. Each PTO gear gear 62 is respectively engaged with the PTO multi-link gear 64. One of the PTO gear gears 62 is transmission-connected to the output end of the PTO clutch 5. A PTO synchronizer 63 is provided on one side of the PTO gear 62. The PTO speed change shaft 61 is the output end of the PTO speed change mechanism 6.

[0042] Preferably, the PTO multi-link gear 64 is a four-link gear, and there are four PTO gears 62, thereby realizing a four-speed conversion PTO output.

[0043] The PTO synchronizer 63 can link any PTO gear 62 with the PTO speed shaft 61; it obtains power from the output end of the PTO clutch 5 through one of the PTO gears 62, and then transmits it to the PTO multi-link gear 64. Different parts of the PTO multi-link gear 64 transmit power to the remaining PTO gears 62, so that each PTO gear 62 has a different speed; thus, when any PTO gear 62 is linked with the PTO speed shaft 61 through the PTO synchronizer 63, the PTO speed shaft 61 can obtain the corresponding speed, realizing multi-speed conversion of PTO output, increasing the output speed change capability of the tractor PTO, and being applicable to various PTO operation modes.

[0044] Furthermore, a power take-off shaft section is provided in the middle of the PTO gear 62 which is transmission-connected to the output end of the PTO clutch 5 . The power take-off shaft section extends into the output end of the PTO clutch 5 and is transmission-connected. The power take-off shaft section is coaxially arranged with the PTO speed change shaft 61 .

[0045] Note: The power take-off shaft section can be a section separated from the PTO speed change shaft 61, or it can be the hub of the PTO gear 62.

[0046] The power take-off shaft section and the output end of the PTO clutch 5 can be driven by a spline, which is easy to install and improves the reliability of the transmission between the PTO clutch 5 and the PTO gear 62.

[0047] Furthermore, every two PTO shift gears 62 are arranged in pairs, and a PTO synchronizer 63 is provided between the two PTO shift gears 62 arranged in pairs.

[0048] The number of PTO synchronizers 63 is saved, the structure is compact, and the cost is reduced.

[0049] Furthermore, the PTO multi-link gear 64 is movably mounted on the output shaft of the primary and secondary speed change mechanism 2 .

[0050] Preferably, the PTO multi-gear 64 is connected to the output shaft of the primary and secondary speed change mechanism 2 via a bearing.

[0051] The output shaft of the primary and secondary speed change mechanism 2 is used to provide installation space for the PTO multi-link gear 64, eliminating the need to set a separate shaft for the PTO multi-link gear 64, reducing the overall volume and weight of the machine and facilitating a lightweight design of the entire machine.

[0052] Furthermore, the PTO output mechanism 7 includes a PTO driving gear 71 and a PTO output shaft 73. The PTO driving gear 71 is sleeved on the PTO speed change shaft 61. The PTO output shaft 73 is sleeved with a PTO passive gear 72. The PTO passive gear 72 is engaged with the PTO driving gear 71. The PTO output shaft 73 is also provided with a composite oil seal special for paddy fields.

[0053] It has a compact structure, is easy to install and has good reliability. It is easy to adapt to paddy field operations through the special composite oil seal for paddy fields.

[0054] Furthermore, the power shift mechanism 1 includes a power input shaft 11, a power output shaft 12, and a reversing idler shaft 13. The power input shaft 11 is provided with a reversing gear 14, a power low gear gear 16, and a power high gear clutch 17. The power output shaft 12 is provided with a reversing clutch 15, a power low gear clutch 18, and a power high gear gear 19. The reversing clutch 15 and the reversing gear 14 are respectively engaged with the idler gear on the reversing idler shaft 13, the power low gear clutch 18 is engaged with the power low gear gear 16, and the power high gear clutch 17 is engaged with the power high gear gear 19. One end of the power output shaft 12 is the first output end of the power shift mechanism 1 , and one end of the power input shaft 11 is the second output end of the power shift mechanism 1 .

[0055] When the reversing clutch 15 is closed, the power of the power input shaft 11 is reversed by the reversing idler shaft 13 and then transmitted to the power output shaft 12 through the reversing clutch 15, thereby realizing reverse gear; when the reversing clutch 15 is disconnected, the high-gear clutch 17 and the low-gear clutch 18 are used to realize the high-gear and low-gear conversion. Under the joint action of the main and auxiliary speed change mechanisms 2, the gear conversion capability is greatly increased, and it can adapt to various road conditions and site operations.

[0056] Furthermore, the second output end of the power shift mechanism 1 is further provided with a hydraulic output gear 81 ; and further comprises a hydraulic power take-off shaft 8 , wherein the hydraulic power take-off shaft 8 is connected to the hydraulic output gear 81 via an idler gear transmission.

[0057] Preferably, a hydraulic power take-off gear is provided on the hydraulic power take-off shaft 8, the hydraulic power take-off gear is meshed with the idler gear, and the idler gear is meshed with the hydraulic output gear 81; a hydraulic power take-off port is provided at one end of the hydraulic power take-off shaft 8, an internal spline is provided in the hydraulic power take-off port, and the input shaft of the hydraulic pump can be inserted into the hydraulic power take-off port and meshed with the internal spline.

[0058] The hydraulic pump of the hydraulic system can obtain power through the hydraulic power take-off shaft 8, which enables the hydraulic pump to be installed on the transmission system. It can replace the solution of installing the hydraulic pump used for steering and lifting on the engine on traditional tractors, reducing the hydraulic pipelines in the engine compartment, making the pipeline layout simpler and the maintenance cost low.

[0059] Furthermore, it also includes a front drive mechanism 9 , and a front drive output gear 91 is provided on the output shaft of the main and auxiliary speed change mechanism 2 , and the front drive mechanism 9 is transmission-connected to the front drive output gear 91 .

[0060] The front drive mechanism 9 is used to connect the front axle assembly. When the front drive mechanism 9 is working, the four-wheel drive mode can be realized, which reduces the turning radius of the tractor and improves the terrain adaptability.

[0061] Furthermore, the front-drive mechanism 9 includes a front-drive speed change shaft 92 and a front-drive output shaft 93. The front-drive speed change shaft 92 is provided with a front-drive high-speed gear and a front-drive low-speed gear. The front-drive output shaft 93 is provided with a front-drive high-speed clutch 94 and a front-drive low-speed clutch 95. The front-drive high-speed clutch 94 is engaged with the front-drive high-speed gear, and the front-drive low-speed clutch 95 is engaged with the front-drive low-speed gear; the front-drive low-speed gear is engaged with the front-drive output gear 91.

[0062] The front-wheel drive high-speed clutch 94 and the front-wheel drive high-speed gear are used for double-speed transmission, so that the front wheels can be operated to rotate faster when turning, and the steering can be completed faster, which reduces the turning radius; gear shifting is achieved through the wet clutch, which improves the operating comfort.

[0063] Furthermore, a parking brake 20 is provided on the output shaft of the main and auxiliary transmission mechanism 2 .

[0064] To facilitate parking after stopping, by braking the output shafts of the main and auxiliary speed change mechanisms 2, the central transmission mechanism 3 and the front drive mechanism 9 have no power input, thus achieving parking brakes on the front and rear wheels.

[0065] Furthermore, the main and auxiliary speed change mechanism 2 includes a main speed change shaft 21, an auxiliary speed change shaft 22 and an intermediate shaft 23. The main speed change shaft 21 is provided with a first main speed change gear pair, and the auxiliary speed change shaft 22 is provided with an auxiliary speed change gear pair. The first main speed change gear pair and the auxiliary speed change gear pair are respectively connected to the intermediate shaft 23 in a transmission manner. The main transmission shaft 21 is the input shaft of the main and auxiliary transmission mechanisms 2 ; the auxiliary transmission shaft 22 is the output shaft of the main and auxiliary transmission mechanisms 2 .

[0066] Preferably, the first main speed gear pair and the auxiliary speed gear pair each include two loose gears 24, and a main speed synchronizer 25 is provided between the two loose gears 24 of the first main speed gear pair; an engaging sleeve is provided between the two loose gears 24 of the auxiliary speed gear pair; and a plurality of fixed gears 26 are provided on the auxiliary speed shaft 22, and each loose gear 24 is meshed with a corresponding fixed gear 26.

[0067] Through the coordination of the three-axis main and auxiliary speed change, the total number of gears is at least twice that of the main speed change gears, which increases the number of gears and can match a variety of speed output capabilities.

[0068] Furthermore, a second speed change gear pair is provided on the intermediate shaft 23 , and the second speed change gear pair is transmission-connected to the main speed change shaft 21 .

[0069] Preferably, there are two pairs of first main speed gear pairs, one pair of second speed gear pairs, and one pair of auxiliary speed gear pairs, achieving a 12-speed transmission. The second speed gear pair includes two loose gears 24, with a main speed synchronizer 25 located between them. The main speed shaft 21 is provided with multiple fixed gears 26, with each loose gear 24 of the second speed gear pair meshing with a corresponding fixed gear 26 on the main speed shaft 21.

[0070] The first main speed gear pair and the second speed gear pair cooperate to achieve gear superposition and a compact structure.

[0071] In the description of the present invention, it should be understood that if there appear descriptive terms indicating orientation, direction or positional relationship, such as: "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., the orientation or positional relationship indicated in this specification is based on the orientation or positional relationship shown in the accompanying drawings, which is only for the convenience of understanding the present invention and simplifying the description, and does not indicate or imply that the part, element or whole referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0072] In addition, if there are order description terms, such as "first", "second", etc., their purpose in this specification is to facilitate understanding or simplify the description. For example, in order to distinguish multiple technical features with the same type or function, but they have to be mentioned separately, this specification may use prefix or suffix order description terms to distinguish them. Therefore, it cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" can explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0073] In the present invention, if terms describing the relative functional relationship of structures are used, such as "install", "connect", "connect", "fix", etc., they should be understood in a broad sense unless otherwise clearly specified and limited. For example, "install", "connect", "connect", etc. can be fixed connections, detachable connections, or integrated; can be mechanical connections or electrical connections; can be direct connections or indirect connections through an intermediate medium, can be internal connections between two elements or an interactive relationship between two elements; "fix" can be an integrated fixation or a detachable fixation through fasteners; can be a direct fixation or a fixation through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above-mentioned descriptive terms in the present invention can be understood according to the specific circumstances, the context, the coherence of the preceding and following texts, etc.

[0074] In the present invention, if descriptive terms with ancillary or connecting meaning appear, for example, a first feature being "on" or "below" a second feature, these should not be construed in a limiting sense unless otherwise expressly specified or limited. For example, "on" or "below" may refer to direct contact between the first and second features, or indirect contact between the first and second features through an intermediary. Persons of ordinary skill in the art will understand the specific meanings of these descriptive terms in the present invention based on the specific circumstances, context, and coherence of the preceding and following texts.

[0075] Furthermore, when a first feature is “above,” “above,” or “above” a second feature, it may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. When a first feature is “below,” “below,” or “below” a second feature, it may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0076] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. In addition, those skilled in the art may combine and combine the different embodiments, examples and features of different embodiments and examples described in this specification, unless there is any contradiction, and these combinations or combinations should all fall within the scope of the present invention.

[0077] Although the embodiments of the present invention have been shown and described above, it is understood that the above embodiments are illustrative and are not to be construed as limiting the present invention. Changes, modifications, substitutions and variations of the above embodiments made by persons of ordinary skill in the art within the scope of information available through public channels and in combination with the technical inspiration provided by the present application documents are still within the scope of protection of the present application.

Claims

1. A power shift transmission system for a paddy field tractor, characterized by: include: A power shift mechanism (1), wherein the power shift mechanism (1) is provided with a first output end and a second output end; A main and auxiliary speed change mechanism (2), wherein the input shaft of the main and auxiliary speed change mechanism (2) is transmission-connected to the first output end of the power shift mechanism (1), and the output shaft of the main and auxiliary speed change mechanism (2) is transmission-connected to the central transmission mechanism (3); A PTO clutch (5), wherein an input end of the PTO clutch (5) is transmission-connected to a second output end of the power shift mechanism (1); A PTO speed change mechanism (6) is provided, wherein the input end of the PTO speed change mechanism (6) is transmission-connected to the output end of the PTO clutch (5), and the output end of the PTO speed change mechanism (6) is transmission-connected to a PTO output mechanism (7).

2. The power shift transmission system for a paddy field tractor according to claim 1, characterized in that: The PTO speed change mechanism (6) comprises a PTO speed change shaft (61) and a PTO multi-link gear (64); a plurality of PTO gears (62) are movably sleeved on the PTO speed change shaft (61); each PTO gear (62) is respectively engaged with the PTO multi-link gear (64); one of the PTO gears (62) is transmission-connected to the output end of the PTO clutch (5); a PTO synchronizer (63) is provided on one side of the PTO gear (62); and the PTO speed change shaft (61) is the output end of the PTO speed change mechanism (6).

3. The power shift transmission system for a paddy field tractor according to claim 2, characterized in that: A power take-off shaft section is provided in the middle of a PTO gear (62) that is transmission-connected to the output end of the PTO clutch (5). The power take-off shaft section extends into the output end of the PTO clutch (5) and is transmission-connected. The power take-off shaft section is coaxially arranged with the PTO speed change shaft (61).

4. The power shift transmission system for a paddy field tractor according to claim 2, characterized in that: Every two PTO shift gears (62) are arranged in pairs, and a PTO synchronizer (63) is provided between the two PTO shift gears (62) arranged in pairs.

5. The power shift transmission system for a paddy field tractor according to claim 2, characterized in that: The PTO multi-link gear (64) is movably sleeved on the output shaft of the primary and secondary speed change mechanism (2).

6. The power shift transmission system for a paddy field tractor according to claim 1, characterized in that: The PTO output mechanism (7) comprises a PTO driving gear (71) and a PTO output shaft (73). The PTO driving gear (71) is sleeved on the PTO speed change shaft (61). The PTO output shaft (73) is sleeved with a PTO passive gear (72). The PTO passive gear (72) is meshed with the PTO driving gear (71). The PTO output shaft (73) is also provided with a composite oil seal specially used for paddy fields.

7. The power shift transmission system for a paddy field tractor according to claim 1, characterized in that: The power shift mechanism (1) comprises a power input shaft (11), a power output shaft (12) and a reversing idler shaft (13); the power input shaft (11) is provided with a reversing gear (14), a power low gear gear (16) and a power high gear clutch (17); the power output shaft (12) is provided with a reversing clutch (15), a power low gear clutch (18) and a power high gear gear (19); the reversing clutch (15) and the reversing gear (14) are respectively engaged with the idler gear on the reversing idler shaft (13); the power low gear clutch (18) is engaged with the power low gear gear (16); and the power high gear clutch (17) is engaged with the power high gear gear (19); One end of the power output shaft (12) is the first output end of the power shift mechanism (1), and one end of the power input shaft (11) is the second output end of the power shift mechanism (1).

8. The power shift transmission system for a paddy field tractor according to claim 7, characterized in that: The second output end of the power shift mechanism (1) is also provided with a hydraulic output gear (81); and further comprises a hydraulic power take-off shaft (8), wherein the hydraulic power take-off shaft (8) and the hydraulic output gear (81) are connected via an idler gear transmission.

9. The power shift transmission system for a paddy field tractor according to claim 1, characterized in that: It also includes a front drive mechanism (9), and a front drive output gear (91) is provided on the output shaft of the main and auxiliary speed change mechanism (2), and the front drive mechanism (9) is transmission-connected to the front drive output gear (91); The front drive mechanism (9) comprises a front drive speed change shaft (92) and a front drive output shaft (93); a front drive high-speed gear and a front drive low-speed gear are provided on the front drive speed change shaft (92); a front drive high-speed clutch (94) and a front drive low-speed clutch (95) are provided on the front drive output shaft (93); the front drive high-speed clutch (94) is engaged with the front drive high-speed gear, the front drive low-speed clutch (95) is engaged with the front drive low-speed gear; and the front drive low-speed gear is engaged with the front drive output gear (91).

10. The power shift transmission system for a paddy field tractor according to claim 1, characterized in that: A parking brake (20) is also provided on the output shaft of the main and auxiliary speed change mechanism (2); The main and auxiliary speed change mechanism (2) comprises a main speed change shaft (21), an auxiliary speed change shaft (22) and an intermediate shaft (23); the main speed change shaft (21) is provided with a first main speed change gear pair, the auxiliary speed change shaft (22) is provided with an auxiliary speed change gear pair, and the first main speed change gear pair and the auxiliary speed change gear pair are respectively connected to the intermediate shaft (23); Wherein, the main speed change shaft (21) is the input shaft of the main and auxiliary speed change mechanisms (2); the auxiliary speed change shaft (22) is the output shaft of the main and auxiliary speed change mechanisms (2); The intermediate shaft (23) is also provided with a second speed change gear pair, which is transmission-connected to the main speed change shaft (21).

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