Gearbox capable of outputting power forwards and backwards and small agricultural tractor

Abstract

The utility model relates to the technical field of agricultural machinery, in particular to a gearbox capable of outputting power front and back and a small agricultural tractor with the gearbox, the gearbox comprises an input shaft for inputting engine power and a variable shaft, and the variable shaft is sequentially provided with an auxiliary gear shifting mechanism and an auxiliary main gear shifting gear set; a rear axle output shaft is arranged on the coaxial line of the intermediate shaft; comprising a power output shaft and a front power output shaft, and the front power output shaft comprises a front power gear. Through cooperation of the input shaft, the variable-speed shaft, the intermediate shaft and the reverse gear set and reasonable layout of the gear shafts, multi-gear speed change is achieved, transmission to the variable-speed shaft, the power output shaft and the reverse gear set is achieved through the arrangement of the intermediate shaft, one-shaft multi-transmission is achieved, the space of the gear box is greatly reduced, and the gear box can be miniaturized. Meanwhile, the front power output shaft and the power output shaft are matched to output front power and back power, and power output is richer.

Description

Technical Field

[0001] The utility model relates to the technical field of agricultural machinery, in particular to a gearbox capable of outputting power forward and backward, and a small agricultural tractor with the gearbox. Background Art

[0002] Tractors typically serve as power units, carrying agricultural implements for operation. Tractors with front power outputs can carry implements such as bulldozers, snowplows, and lawn mowers; tractors with rear power outputs can carry implements such as trenchers, rotary tillers, and potato harvesters. High-horsepower tractors, due to their large size and ample space, can be designed with both front and rear power outputs. Low-horsepower tractors, however, due to their smaller size and limited space, only have rear power outputs, meaning that implements can only be mounted at the rear of the tractor.

[0003] At present, the smallest domestic riding tractor has a horsepower of about 35. It has a heavy body and a large turning radius, making it difficult to operate in small fields, orchards, vegetable greenhouses and other places with small operating space in hilly and mountainous areas. Only walk-behind tractors can adapt to the above-mentioned sites, but walk-behind tractors have low working efficiency and high labor intensity for operators. Moreover, the speed transmission method of most medium and large agricultural machinery is hydraulic continuously variable transmission + mechanical speed transmission. The hydraulic continuously variable transmission (HST) can well achieve stepless speed change and can realize fast switching between forward and reverse, but the cost of HST is relatively high. Using it on agricultural machinery will greatly increase the cost. At the same time, hydraulic speed change has relatively high requirements for the use environment, and it is even more disadvantageous to use it on small agricultural machinery four-wheel tractors. For example Figure 29 As shown, Chinese patent CN206708343U, entitled "A gearshift transmission particularly suitable for agricultural machinery," discloses a gearbox that achieves forward and reverse switching through a forward-reverse switching control device, thereby achieving forward and reverse multi-speed switching. The forward-reverse switching control device includes a wet dual clutch, which increases manufacturing and maintenance costs. Furthermore, the input shaft, shift shaft, gear transmission shaft, clutch support shaft, and output driven steering shaft of the gearbox are almost lined up in a row. While this ensures the sensitivity of gear switching, the standing space is large, the gear shifting efficiency is low, and the manufacturing and operating costs remain high. Chinese patent CN218294341U discloses "A transmission system for agricultural machinery." The fifth gear disposed on the third shaft meshes with the fourth, sixth, and seventh gears, respectively, to achieve three forward gears, and the fifth gear meshes with the tenth gear to achieve reverse gear. Although this transmission system achieves three forward gears and one reverse gear with three shafts, it avoids the problem of significantly increasing the size of the transmission system. However, three gears cannot meet the use requirements of current agricultural tractors and four-wheel vehicles, and are generally suitable for walk-behind tractors.

[0004] For agricultural tractors, it is necessary to have appropriate gears to complete various operations such as rotary tillage, plowing, harrowing, deep loosening, soil preparation, sowing, and transportation, and to control the operation to be convenient and low-cost, which itself has contradictory problems in technology. The setting of the shifting structure of agricultural tractors has always troubled the progress of tractor technology, and is also a difficult problem that needs to be overcome by the present utility model. Chinese patent CN115489301A discloses "a tractor transmission system and a tractor", which uses an independent shuttle gear on the clutch assembly for shifting, and sets two shift forks on the same fork shaft for forward and reverse shifting, with clear shifting logic. However, the two forks are highly correlated with each other, and the fluctuation conversion spacing requirement is high, which cannot meet the working requirements of most gearboxes.

[0005] The utility model is designed to design a gearbox for a small-horsepower wheeled tractor specially used in hilly and mountainous areas, which can output power at the front and rear, and a small agricultural tractor with a power of about 35 horsepower. Summary of the Invention

[0006] In response to the problem of complex transmission mechanism in the above-mentioned prior art, the utility model provides a gearbox that can output power at the front and rear. The gearbox can be miniaturized and reduce costs through the reasonable arrangement of gears and gear shafts. At the same time, it can output front power and rear power, which is convenient for mounting different agricultural implements at the front and rear. At the same time, the utility model also provides a small agricultural tractor, which is more flexible to use with tractors of 35 horsepower or less.

[0007] According to the present invention, a gearbox capable of outputting power to the front and rear is provided, comprising a housing, an input shaft for inputting engine power, and an input main gear fixed thereon, characterized in that a speed change shaft is provided in the axial direction of the input shaft, and a slave shift mechanism and a sub-master shift gear set are sequentially provided on the speed change shaft;

[0008] The intermediate shaft comprises an input slave gear meshing with the input main gear and a main shift gear set fixed to the intermediate shaft, wherein the slave shift mechanism slides to different positions and meshes with gears of different teeth of the main shift gear set to achieve main speed change; a rear axle output shaft is coaxially arranged on the intermediate shaft, and the rear axle output shaft is provided with a slave shift mechanism, wherein the slave shift mechanism can slide left and right on the rear axle output shaft and cooperate with the slave main shift gear set to achieve slave speed change;

[0009] The first reverse gear set includes a first gear and a second gear that rotate synchronously, wherein the first gear is engaged with the main shift gear set, and the slave shift mechanism slides to engage with the second gear to achieve reverse gear shift of the main speed change;

[0010] The power output shaft comprises a power output shaft, wherein the power output shaft is provided with a third shift gear set and a second reverse gear, the second reverse gear is idle on the power output shaft and meshes with the second gear of the first reverse gear set and idly rotates, the third shift gear set slides on the power output shaft and sequentially meshes with the main shift gear set and is transmission-connected with the second reverse gear, thereby achieving shifting of power output from the power output shaft;

[0011] It includes a front power output shaft, which includes a front power gear. The front power gear is connected to a transmission position of the third shift gear set; the third shift gear set drives the front power output shaft to output power.

[0012] This utility model achieves multi-speed shifting through the coordination of the input shaft, speed-change shaft, intermediate shaft, and reverse gear set, as well as the rational layout of the gear shafts. The intermediate shaft transmits power to the speed-change shaft, power output shaft, and reverse gear set, creating a single shaft with multiple transmissions. This significantly reduces the space required for the gearbox and allows for a more compact gearbox. Furthermore, the coordination of the front power output shaft and the power take-off shaft enables front and rear power output, resulting in a more diverse power output.

[0013] Preferably, a positioning shaft is provided on the lower side of the box body, and a positioning shaft gear is provided on the positioning shaft. The positioning shaft gear is engaged with a transmission position of the third shift gear set for transmission, and the positioning shaft gear is engaged with the front power gear for transmission.

[0014] The positioning shaft of the utility model is arranged at the bottom of the box body and then transmitted to the front power output shaft, which makes the selection and setting of the front power output more convenient and ensures the stability of the output power.

[0015] As a preferred embodiment, the positioning shaft is installed in the transmission case through clearance fit, with one end positioned by the shaft hole of the transmission case and the other end positioned by the end surface of the transmission case front cover. The utility model facilitates the installation and fixation of the positioning shaft.

[0016] Preferably, the inner hole of the positioning shaft gear is fitted with a bearing through clearance fit, and the inner hole of the bearing is mounted on the positioning shaft.

[0017] Preferably, the power output shaft is provided with a clearance-fit external spline sleeve and a fixedly connected external spline. One side of the second reversing gear is provided with a gear external spline. The third shift gear set is provided with an internal spline. The third shift gear set slides, and the internal spline is sequentially connected to the external spline, the external spline sleeve, and the gear external spline. At the position where the third shift gear set is connected to the external spline sleeve, the third shift gear set is meshed with the main shift gear set and the positioning shaft gear. The provision of the external spline sleeve in this utility model prevents simultaneous front and rear power output, reduces excessive power output distribution, and prevents idling of mounted agricultural implements.

[0018] Preferably, the front axle output shaft is included, the front axle output shaft is on a different axis from the speed change shaft and the intermediate shaft, the first reversing gear set is loosely mounted on the front axle output shaft and can idly rotate, the front axle output shaft is fixed with a second synchronous gear, the rear axle output shaft is transmission-connected with a first synchronous gear, the first synchronous gear and the second synchronous gear are meshed and transmitted to synchronize the rotation of the front axle output shaft and the rear axle output shaft. The front axle output shaft of the utility model can output front wheel drive and simultaneously serve as a support shaft for the first reversing gear set, thereby enabling the installation of the first reversing gear set, achieving multiple uses of one shaft, saving space in the gearbox, and reducing costs.

[0019] Preferably, the auxiliary slave shifting mechanism includes an auxiliary speed gear set and an auxiliary low-speed gear, the auxiliary low-speed gear is loosely mounted on the rear axle output shaft and is provided with a left spline, the auxiliary speed gear set is provided with a right spline and is transmission-connected to the rear axle output shaft and can slide left and right; the auxiliary master shifting gear set includes a high-speed gear, a medium-speed gear and a low-speed gear fixedly connected to the speed shaft and arranged in sequence to the left, the low-speed gear is meshed with the auxiliary low-speed gear; the auxiliary speed gear set slides and meshes with the high-speed gear and the medium-speed gear in sequence respectively and can slide to the left spline of the auxiliary speed gear set and the right spline of the auxiliary low-speed gear for transmission, thereby realizing high, medium and low speed conversion.

[0020] Preferably, the slave shift mechanism includes a first shift gear set and a second shift gear set, the main shift gear set includes a first intermediate gear, a second intermediate gear and a third intermediate gear, gear 1 of the first reversing gear set is meshed with the first intermediate gear, sliding the first shift gear set left and right can mesh with the second intermediate gear and the third intermediate gear to achieve first and third gear shifting, sliding the second shift gear set can mesh with the first intermediate gear to achieve second gear shifting, sliding the second shift gear set can mesh with gear 2 of the first reversing gear set to achieve reverse gear shifting, and the first shift gear set and the second shift gear set are respectively provided with a neutral position.

[0021] Preferably, the projections of the axis of the power output shaft and the axis of the first reversing gear set, the speed change shaft, and the intermediate shaft are arranged on the four vertices of a quadrilateral.

[0022] Preferably, it includes a shift operating device, which includes a first shift fork, a second shift fork, a third shift fork and a fourth shift fork. The first shift fork drives the first shift gear set to slide, the second shift fork drives the second shift gear set to slide, the third shift fork drives the third shift gear set to slide, and the fourth shift fork drives the auxiliary speed gear set to slide.

[0023] Preferably, the housing further comprises a left end cover and a support plate, the input shaft and the intermediate shaft, the front axle output shaft and one end of the power output shaft are fixed to the left end cover through bearings, the intermediate shaft, the front axle output shaft, the other end of the power output shaft, one end of the rear axle output shaft and the speed change shaft are connected to the support plate through bearings, a mounting hole is provided at the left end of the input shaft, the right end of the speed change shaft is inserted into the mounting hole, and a first end connecting bearing is provided between the two shafts.

[0024] Preferably, a gearbox lower cover is included, and the front power output shaft is fixed in the gearbox lower cover via a bearing.

[0025] The utility model also provides a small agricultural tractor, comprising the gearbox capable of outputting power frontally and rearwardly, and also comprising front and rear mounting positions, wherein the front and rear mounted agricultural implements can be transmission-connected with the front power output shaft and the power output shaft. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Schematic diagram of the gearbox structure of the embodiment;

[0027] Figure 2 This is a right side view of the gearbox of the embodiment;

[0028] Figure 3 This is a schematic diagram of the transmission structure as viewed from the right rear side of the embodiment;

[0029] Figure 4 Schematic diagram of the right side structure of the transmission of the embodiment;

[0030] Figure 5 This is a partial disassembled diagram of the transmission of the embodiment;

[0031] Figure 6 This is a schematic front view of the gear and shaft structure of the transmission of the embodiment;

[0032] Figure 7 A rear view schematic diagram of the gear and shaft structure of the transmission of the embodiment;

[0033] Figure 8 This is a schematic diagram of the matching relationship between some gears and shaft structures of the transmission in the embodiment;

[0034] Figure 9 for Figure 8 Partial cross-sectional view of the middle A part;

[0035] Figure 10 for Figure 8 Partial cross-sectional view of the middle B section;

[0036] Figure 11 for Figure 8 Partial cross-sectional view of the middle C section;

[0037] Figure 12 for Figure 8 Partial cross-sectional view of the middle D section;

[0038] Figure 13 The structure of the transmission speed change system of the embodiment is intended;

[0039] Figure 14 Schematic diagram of the gear matching relationship between the intermediate shaft and the power output shaft;

[0040] Figure 15 Schematic diagram of the third shift fork structure in the embodiment;

[0041] Figure 16 Schematic diagram of the gearbox structure;

[0042] Figure 17 This is a schematic diagram of the front and rear output power transmission structure of another embodiment;

[0043] Figure 18 This is a schematic diagram of the gear-shaft matching structure of another embodiment;

[0044] Figure 19 This is a schematic diagram of the back structure of the gear-shaft matching in another embodiment;

[0045] Figure 20 This is a schematic diagram of the power output shaft structure of another embodiment;

[0046] Figure 21 This is a schematic diagram of the positioning shaft structure of another embodiment;

[0047] Figure 22 This is a schematic diagram of the structure of the rear PTO in reverse position in another embodiment;

[0048] Figure 23 It is a schematic diagram of the neutral position structure of another embodiment;

[0049] Figure 24 This is a schematic diagram of the structure of the PTO forward position in another embodiment;

[0050] Figure 25 This is a schematic diagram of the neutral position structure of another embodiment;

[0051] Figure 26 This is a schematic diagram of the front PTO position structure of another embodiment;

[0052] Figure 27 An embodiment of the front PTO position reversal;

[0053] Figure 28 This is the tractor of the utility model;

[0054] Figure 29 Attached is the background technology solution.

[0055] The following are marked in the figure:

[0056] 100-gearbox, 110-gearbox body, 111-support plate, 112-support bearing seat, 120-upper cover, 130-left end cover, 131-input bearing seat, 132-output bearing seat, 150-connecting box body, 160-gearbox lower cover.

[0057] 200 - transmission gear assembly, 210 - input shaft, 211 - first end connecting bearing, 212 - input main gear, 220 - speed change shaft, 221 - first spline shaft, 222 - first shift gear set, 223 - second shift gear set, 224 - high speed gear, 225 - low speed gear, 226 - intermediate speed gear;

[0058] 230-power output shaft, 231-second reverse gear, 232-third shift gear set, 233-external spline sleeve, 234-external spline, 240-rear axle output shaft, 241-first synchronous gear, 242-secondary speed gear set, 243-secondary low-speed gear, 244-oil-free bearing, 250-front axle output shaft, 251-first reverse gear set, 2511-bearing, 252-second synchronous gear, 260-intermediate shaft, 261-input slave gear, 262-first intermediate gear, 263-second intermediate gear, 264-third intermediate gear.

[0059] 270-front power output shaft, 271-positioning shaft, 272-positioning shaft gear, 273-front power gear, 274-third reverse gear set;

[0060] 300-shift operating device, 310-first shift fork, 311-first shift fork shaft, 312-sleeve, 313-gear slot, 314-steel ball, 315-compression spring, 320-second shift fork, 321-second shift fork shaft, 330-speed operating shaft, 331-gear shift shaft, 332-fixing sleeve, 333-return spring, 334-baffle, 340-third shift fork, 341-power output shaft, 342-power output pull plate, 343-hollow pin, 344-third shift fork shaft, 3441-reverse gear groove, 3442-first neutral groove, 3443-first forward gear groove, 3444-second neutral groove, 3445-second forward groove, 350-fourth shift fork, 351-high and low speed shaft, 352-high and low speed pull plate, 353-fourth shift fork shaft.

[0061] 401-first axis space; 402-second axis space; 403-third axis space; 404-fourth axis space. DETAILED DESCRIPTION

[0062] In order to further understand the content of the present invention, the present invention is described in detail with reference to the accompanying drawings and embodiments. It should be understood that the embodiments are merely for explanation of the present invention and are not intended to limit the present invention.

[0063] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "clockwise", "counterclockwise", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0064] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this utility model, unless otherwise specified, "plurality" means two or more, unless otherwise explicitly specified.

[0065] In this utility model, unless otherwise specified or limited, the terms "mounted," "connected," "connected," "fixed," etc. should be understood in a broad sense. For example, they may refer to fixed connection, detachable connection, or integral connection; they may also refer to indirect connection through an intermediate medium, or internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on specific circumstances.

[0066] In the present invention, unless otherwise clearly stated or defined, the term "NT-tooth gear" refers to a gear with N being the number of teeth.

[0067] like Figure 1-Figure 2 As shown, the utility model provides a tractor transmission, including a transmission 100, the transmission 100 including a transmission body 110, a transmission cover 120, a left end cover 130, a bottom cover, and a connecting box 150. Figure 28 The figure shows a tractor of the present invention, which includes the above-mentioned tractor transmission and a gear shifting structure.

[0068] Another embodiment is Figure 17 As shown, the gearbox 100 further includes a gearbox lower cover 160 , which is located at the lower part of the gearbox 100 to replace the bottom cover so as to selectively set the front power output shaft 270 .

[0069] The cavity enclosed by the transmission housing 110, the transmission cover 120, the transmission end cover 130, the bottom cover, and the connecting housing 150 houses a transmission gear assembly 200. This transmission gear assembly 200 comprises shafts, gears, and necessary support bearings. These bearings are typically supported and secured by structural components such as baffles within the transmission housing 100. The tractor transmission also includes a shift control device 300. By shifting the transmission gear assembly 200, the shift control device 300 adjusts the gear relationships, enabling high, low, forward, and backward gear shifting.

[0070] like Figure 3-9 As shown, the transmission gear assembly 200 includes an input shaft 210 for inputting engine power, a speed change shaft 220, a power output shaft 230, and a rear axle output shaft 240. In this embodiment, a front axle output shaft 250 and an intermediate shaft 260 are also provided. In another embodiment, as Figure 18-19 As shown, a front power take-off shaft 270 is also included.

[0071] The input shaft 210 is installed in the gearbox 100 through the support of two bearings. Specifically, an input bearing seat 131 is provided on the gearbox cover 130, and the bearing is fixed in the input bearing seat 131, thereby fixing the input shaft 210. The input shaft 210 is fixed only by the gearbox cover 130, so that other transmission shafts can continue to be arranged in the same axial direction as it. In this embodiment, a speed change shaft 220 is provided. In order to better fix the input shaft 210, reinforcing ribs are provided on the outer circumference of the input bearing seat 131, and the input bearing seat 131 is protruding so that two bearings can be arranged inside it. The input shaft 210 is connected to the output end of the engine through a spline sleeve, a universal joint or a spline shaft. After the engine is started, the input shaft 210 starts to run. Of course, this "connection" includes direct connection and indirect connection. The end of the input shaft 210 is directly connected to the engine transmission through a spline sleeve, a universal joint and a spline shaft, and the transmission is stable and efficient, and the manufacturing cost is low. Figure 6 As shown, the input shaft 210 is provided with an input main gear 212, which can be fixedly connected to the main gear 121, or the main gear can be directly made at the end of the input shaft 210. In this embodiment, the input main gear 212 is a 15T helical gear.

[0072] The speed change shaft 220 is fixed by the support of two bearings. In order to better fix the shaft and reduce the installation space, Figure 2 、 Figure 16 As shown, a support plate 111 is provided within the transmission housing 110, and a support bearing seat 112 is provided on the support plate 111. One bearing on the speed change shaft 220 is fixed to the support bearing seat 112, and the other bearing is provided at the outer end (left end) of the speed change shaft 220 and fixed to the connecting housing 150. The support plate, bearing seat, and transmission are integral.

[0073] like Figure 2 ,6, Figure 8-9 As shown, a speed change shaft 220 is coaxially arranged at the rear of the input shaft 210. The two are on the same axis, that is, the axis lines of the two shafts coincide, and the two shafts are defined as the first axis line space 401. The left end of the speed change shaft 220 is connected to the right end of the input shaft 210 through the first end connecting bearing 211. Figure 9 As shown, a mounting hole is provided at the right end of the input shaft 210, and the left end of the speed change shaft 220 is inserted into the mounting hole. A first-end connecting bearing 211 is provided between the two shafts. Since the speed change shaft 220 and the inner ring of the first-end connecting bearing 211 are clearance-matched, and the engine input shaft 210 and the outer ring of the first-end connecting bearing 211 are clearance-matched, the speed change shaft 220 does not rotate when the engine input shaft 210 is running. The two shafts do not interfere with each other's rotation and can support each other, making the fixation of the two shafts more secure and stable. Of course, a mounting hole for a needle roller bearing can also be provided at the right end of the speed change shaft 220, and the needle roller bearing can be placed in the mounting hole. The first-end connecting bearing 211 can be a needle roller bearing, which can save space, and can also be replaced by other bearings such as graphite bearings.

[0074] A first spline shaft 221 is provided on the right side of the speed change shaft 220. The slave shift mechanism is sleeved on the first spline shaft 221 and can slide left and right, and is connected to the speed change shaft 220 in transmission. The slave shift mechanism and the main shift gear set form a main shift system. The position of the slave shift mechanism is adjusted by the shift fork so that different gears of the slave shift mechanism and the main shift gear set are engaged to form a transmission with different transmission ratios. The slave shift mechanism and the main shift gear set include a first shift gear set 222 and a second shift gear set 223. The first shift gear set 222 and the second shift gear set 223 are respectively mounted on the first spline shaft 221 through spline fitting and are connected to slide left and right. Each gear set includes two large and small linkage gears to form different transmission ratios. The linkage gear can be an integral gear or two gears fixedly connected. In one specific embodiment, the first shift gear set 222 includes a 31T gear and an 18T gear, the two gears are linked together with a shift fork positioned between them; the second shift gear set 223 includes a 28T gear and a 24T gear, the two gears are linked together with a shift fork positioned between them. The speed change shaft 220 is driven and fixedly connected to the left side of the support plate 111 in sequence to form a secondary main shift gear set. The secondary main shift gear set cooperates with the secondary slave shift mechanism to achieve secondary speed change. In one specific embodiment, the high-speed gear 224 is a 29T gear, the intermediate-speed gear 226 is a 23T gear, and the low-speed gear 225 is a 13T gear. Power is transmitted to the first spline shaft 221 through the first shift gear set 222 and the second shift gear set 223, and is transmitted through the high-speed gear 224, the medium-speed gear 226 and the low-speed gear 225 on the speed shaft 220, forming 12 gears.

[0075] The front axle output shaft 250 is supported by two bearings and mounted within the transmission 100. The front axle output shaft 250 is parallel to the input shaft 210 and the transmission shaft 220, defining a second axis space 402. The two bearings can be fixed to the support plate 111 and the left end cap 130, respectively. One end of the front axle output shaft 250 extends out of the left end cap 130 to form the output end. Therefore, an output bearing seat 132 can be provided at the right end of the left end cap 130, along with reinforcing ribs and other structures.

[0076] A first reversing gear set 251 is provided in an empty sleeve on the front axle output shaft 250. The first reversing gear set 251 is mounted on the front axle output shaft 250 through a clearance fit of two needle bearings and is fixed with a shaft retaining ring to prevent it from sliding. Specifically, the first reversing gear set 251 can be mounted on the front axle output shaft 250 through needle bearings. The front axle output shaft 250 supports the first reversing gear set 251, and the two do not generate transmission. The first reversing gear set 251 includes a 24T tooth gear and a 21T tooth gear, and the two gears rotate synchronously as a combined gear. The end of the front axle output shaft 250, that is, the left side of the support plate 111, is fixedly installed with a second synchronous gear 252, and the second synchronous gear 252 is a 20T tooth gear. The front axle output shaft 250 rotates synchronously with the rear axle output shaft 240 through the second synchronous gear 252, and also provides a mounting shaft for the first reversing gear set 251, which can not only realize the front driving force output, but also reverse the gear, realize multiple uses of one shaft and one gear, and realize the simplification of the gearbox structure and the improvement of mechanical efficiency and service life.

[0077] like Figure 8 As shown in Figures 12-13, the power output shaft 230 is supported by two bearings and installed in the gearbox 100, parallel to the input shaft 210 and the front axle output shaft 250, and outside the plane formed by the input shaft 210 and the front axle output shaft 250, which is defined as the third axis centerline space 403. Specifically, it can be set as follows: a bearing is installed at the left end of the power output shaft 230, and the bearing is fixed on the left end cover 130; another bearing is installed at the right end of the power output shaft 230, and the bearing is fixed on the support plate 111. A second reversing gear 231 and a third shifting gear set 232 are provided between the two bearings. As shown Figure 10 As shown, the second reverse gear 231 is mounted on the power output shaft 230 through a clearance fit (loose sleeve) and fixed with a sleeve and a bearing to prevent it from sliding left and right. When the power output shaft 230 is running, the second reverse gear 231 does not rotate. The second reverse gear 231 is a 28T gear.

[0078] The third shift gear set 232 is mounted on the power output shaft 230 via a splined transmission. The third shift gear set 232 comprises a 24T gear and an 18T gear, with a shift fork positioned between the two gears. The third shift fork 340, which engages the third shift gear set 232, allows for controlled left and right sliding movement on the power output shaft 230. The right end of the power output shaft 230 is splined, allowing power to be output via a splined sleeve, universal joint, or splined shaft. The power output shaft 230 is used to drive agricultural implements mounted on the agricultural vehicle, providing independent drive for the implements.

[0079] When agricultural tractors are equipped with front and rear implements, they require front and rear PTO connections (power take-offs) for connecting the implements and delivering power. Because tractors often carry many implements at the rear, PTO shaft 230 is typically connected to the rear PTO.

[0080] If front mounting is required, in another embodiment, Figure 17-27 As shown, a front power output shaft 270 can be provided, and the front power output shaft 270 is connected to the front PTO position through gear meshing with the gear provided on the power output shaft 230, so that power can be output at both the front and rear ends.

[0081] In some specific embodiments, the front power output shaft 270 is arranged on the gearbox lower cover 160. The front power output shaft 270 is fixedly connected to the gearbox lower cover 160 through two bearings, and one end protrudes from the gearbox lower cover 160 and is transmission-connected to the front PTO position.

[0082] like Figure 21 As shown, a gear transmission system, locating shaft 271, is provided between the PTO shaft 230 and the front PTO shaft 270. This locating shaft 271 is installed within the transmission case through a clearance fit, with one end positioned by a shaft hole in the transmission case and the other end positioned by the end face of the transmission front cover (left end cover). This locating shaft 271 is equipped with a locating shaft gear 272, a 27T gear with a deep groove ball bearing installed within its inner bore through a clearance fit. The bearing's inner bore is mounted on locating shaft 271. The 27T gear is secured within the transmission case via a friction-reducing washer and the bearing's end face, and can rotate about the locating shaft.

[0083] The front power output shaft 270 includes an output end and a front power gear 273 , and the front power gear 273 is a 17T gear.

[0084] The third shift gear set 232 includes a 24-tooth gear and an 18-tooth gear. When the third shift fork 340 is moved, the 18-tooth gear simultaneously meshes with the third intermediate gear 264 (the 25-tooth gear) and the 27-tooth gear on the intermediate gear shaft. After the engine is started, intermediate shaft 260 continues to rotate, driving the third shift gear set 232, which is meshed with its 25-tooth gear, to rotate. This in turn drives the positioning shaft gear 272.

[0085] Since the gear 27T is engaged with the front power gear 273 on the front power output shaft 270, the front power output shaft 270 also rotates at the same time. Generally, a spline is provided at the end of the front power output shaft 270, and power can be transmitted to the front mounted agricultural implement through the existing transmission structure.

[0086] To prevent the PTO shaft 230 and the front PTO shaft 270 from operating simultaneously, when the third shift gear set 232 is mated with the positioning shaft gear 272, the PTO shaft 230 is provided with a clearance-fitting external splined sleeve 233 and a fixedly connected external splined sleeve 234. Specifically, the splined sleeve on the right side of the PTO shaft 230 is replaced with an external splined sleeve 233 that is clearance-fitting with the PTO shaft 230, while the external splined sleeve 234 on the left side remains fixedly connected. The external splined sleeve 233 does not transmit power to the PTO shaft 230 and is connected to the internal splined sleeve of the third shift gear set 232. Since the internal spline of the third shift gear set 232 is completely seated on the external splined sleeve 233, and the external splined sleeve 233 is clearance-fitting with the PTO shaft 230, the PTO shaft 230 does not operate.

[0087] At this time, the external spline sleeve 233 and the second counter gear 231 are installed on the power output shaft 230 through a clearance fit. When the external spline sleeve 233 and the second counter gear 231 are running, the power output shaft 230 does not rotate. The external splines of the external spline sleeve 233, the splines of the power output shaft 230, and the external splines of the second counter gear 231 have the same parameters.

[0088] like Figure 3-8 As shown in Figures 12 and 13 , the rear axle output shaft 240 is mounted within the transmission housing 110 and the rear axle gearbox via bearings at both ends. In one specific embodiment, the bearing at one end of the rear axle output shaft 240 is fixed to the support plate 111, while the bearing at the other end, i.e., the output end, is fixed to the rear axle gearbox. The axis of the rear axle output shaft 240 is parallel to the input shaft 210, the front axle output shaft 250, and the power take-off shaft 230, and is outside the plane formed by any two axis centers, defining a fourth axis centerline space 404.

[0089] The first synchronous gear 241 is mounted on the rear axle output shaft 240 through a spline fit and secured with a shaft retaining ring and bearings to prevent slippage. The first synchronous gear 241 is a 13T gear. The first synchronous gear 241 meshes with the second synchronous gear 252, synchronizing the output rotation of the rear axle output shaft 240 with the front axle output shaft 250, thereby achieving four-wheel drive for the agricultural vehicle.

[0090] The rear axle output shaft 240 is provided with a secondary slave shift mechanism that slides on the rear axle output shaft 240 to enable transmission. A common installation method involves providing a splined shaft on the rear axle output shaft 240, with the secondary slave shift mechanism having a splined fit, so that the secondary slave shift mechanism slides on the rear axle output shaft 240 to enable transmission. The secondary slave shift mechanism slides left and right to engage with the secondary master shift gear set to achieve secondary speed change.

[0091] The auxiliary slave shift mechanism includes an auxiliary speed gear set 242, which is mounted on the rear axle output shaft 240 via a splined fit. A fourth shift fork 350 engages the auxiliary speed gear set 242, enabling it to slide left and right on the rear axle output shaft 240. The auxiliary speed gear set 242 comprises a 20T gear and a 14T gear, which are fixedly connected and can be linked together, with a shift fork latch located between them. A high- and low-speed rotating shaft 351 is connected to a high- and low-speed pull plate 352 via a hollow pin. One end of the high- and low-speed rotating shaft 351 engages the fourth shift fork 350. Clockwise and counterclockwise rotation of the high- and low-speed pull plate 352 controls the left and right sliding of the fourth shift fork 350. The auxiliary slave shift mechanism features an external spline on the right side of the auxiliary speed gear set 242, which engages with an internal spline on the left side of the auxiliary low-speed gear 243 on the right side. The auxiliary low-speed gear 243 is a 42T gear with an oilless bearing 244 (for lubrication) inserted into its gear hole. The gear is then mounted on the rear axle output shaft 240 and secured with a shaft retaining ring and anti-friction washers to prevent sideways movement. This allows the auxiliary low-speed gear 243 to rotate freely. The oilless bearing 244 (containing graphite) is loosely fitted to the rear axle output shaft 240, and the auxiliary low-speed gear 243 is also loosely fitted to the oilless bearing 244. When the auxiliary low-speed gear 243 rotates, the rear axle output shaft 240 does not rotate, and the oilless bearing 244 provides lubrication. The auxiliary transmission gear set 242 and the auxiliary low-speed gear 243 are splined together to achieve the third stage of auxiliary transmission.

[0092] like Figure 12-13As shown, the intermediate shaft 260 is mounted within the transmission case via two bearings. The input slave gear 261 is splined to the intermediate shaft 260 and secured with bearings to prevent slippage. The input slave gear 261 is a helical gear 28T. The left end of the intermediate shaft 260 is secured to the left end cap 130 via a bearing, while the right end is secured to the support plate 111 via a bearing. These two bearings ensure a more stable transmission of the intermediate shaft 260. The rear axle output shaft 240 is coaxially located to the right of the intermediate shaft 260, forming a fourth axis space. The intermediate shaft 260 is fixedly connected to the main shift gear set, which consists of several gears with varying tooth counts, each fixed to the intermediate shaft 260. The number of gears is determined based on the number of gear positions. In this embodiment, the main shift gear set and the slave shift mechanism work together to achieve the main shift. Therefore, the main shift gear set includes the following gears fixed to the intermediate shaft 260 in sequence: the first intermediate gear 262 is a 19T gear, the second intermediate gear 263 is a 12T gear, and the third intermediate gear 264 is a 25T gear.

[0093] Input master gear 212 meshes with input slave gear 261, which is splined to intermediate shaft 260. Therefore, when the engine input shaft rotates, intermediate shaft 260 also rotates. At this time, first reverse gear set 251 (a 21T gear) meshes with first intermediate gear 262 fixed to intermediate shaft 260, and also rotates synchronously. However, since first reverse gear set 251 is mounted on front axle output shaft 250 via a needle bearing, front axle output shaft 250 does not rotate.

[0094] At this moment, the 24T teeth on the first reverse gear set 251 mesh with the second reverse gear 231, so the second reverse gear 231 also rotates synchronously. Since the second reverse gear 231 is installed on the power output shaft 230 through clearance fit, the power output shaft 230 does not operate.

[0095] In some embodiments, as Figure 2As shown, the first axis space 401, the second axis space 402, the third axis space 403, and the fourth axis space 404 are arranged roughly according to the vertices of a quadrilateral. This means that the projections of the axis centerline of the power output shaft 230, the axis centerlines of the first counter-rotating gear set 251, the speed change shaft 220, and the axis centerlines of the intermediate shaft 260 are arranged at the four corners of the quadrilateral. The projections of any three axis centerlines are not on the same straight line. This projection is the projection of the axis centerline onto a vertical plane, forming a single point. The input main gear 212 on the first axis space 401 meshes with the input slave gear 261 on the fourth axis space 404, transmitting power to the intermediate shaft 260. The first intermediate gear 262 on the fourth axis space 404 meshes with the first counter-rotating gear set 251 on the second axis space 402. The first counter-rotating gear set 251 on the second axis space meshes with the second counter-rotating gear 231 on the third axis space 403.

[0096] When the engine is input, the four axis space parts of the shaft enter into idling. At this time, each shift gear is in the neutral position and does not mesh with other gears.

[0097] The main speed change is: the first shift fork 310 and the second shift fork 320 are moved so that the first shift gear set 222 and the second shift gear set 223 on the first axis space 401 are engaged with the first intermediate gear 262, the second intermediate gear 263, the third intermediate gear 264 and the first reverse gear set 251 of the second axis space 402 in the fourth axis space 404, thereby realizing a 4-stage main speed change in the layout of the first, fourth and second axis spaces.

[0098] Auxiliary speed change: The auxiliary low-speed gear 243 and the auxiliary speed change gear set 242 in the fourth axis space are respectively engaged with the low-speed gear 225, the medium-speed gear 226 and the high-speed gear 224 on the first axis space 401 to achieve a three-stage auxiliary speed change.

[0099] Power output speed change: the second reverse gear 231 of the third axis space 403 is engaged with the 24T gear of the first reverse gear set 251 of the second axis space 402; the third shift gear set 232 (24T gear and 18T gear) of the third axis space 403 is engaged with the first intermediate gear 262 (19T gear) and the third intermediate gear 264 (25T gear) on the intermediate shaft 260 of the fourth axis space 404, respectively, to achieve the gear change of reverse 1st gear and forward 1st and 2nd gears.

[0100] By providing an intermediate shaft 260 to provide variable speed transmission for the speed change shaft 220 and the power output shaft 230, with one shaft and two speed change shaft outputs, the efficient setting of the intermediate shaft 260 makes the gearbox more compact. By providing the first reverse gear set 251 on the front axle output shaft 250, reverse gears are provided for the speed change shaft 220 and the power output shaft 230 respectively, and one reverse gear set is used for multiple purposes. The setting of the four axis spaces forms a transmission coordination between the gears in four plane dimensions, making the gearbox structure compact and space-saving. In addition, by cooperating with the shift operating lever, a clutchless multi-speed transmission is achieved, simplifying the gearbox structure and greatly reducing production and use costs.

[0101] Regarding the shift operating device 300, Figures 3 to 6 As shown, the shift control device 300 includes a first shift fork 310 and a second shift fork 320 located within the transmission 100, and a shift control shaft 330 controlled from outside the transmission 100. The first shift fork 310 is clamped on the first shift gear set 222 and can be controlled to slide left and right on the first spline shaft 221 of the speed shaft 220; the second shift fork 320 is clamped on the second shift gear set 223 and can be controlled to slide left and right on the first spline shaft 221 of the speed shaft 220.

[0102] The speed shift operating shaft 330 is mounted on the upper cover 120, and the gear shift shaft 331 is mounted on the speed shift operating shaft 330 and fixed by a fixing sleeve 332 and a return spring 333. The speed shift operating shaft 330 controls the first shift fork 310 and the second shift fork 320 to shift gears by sliding left and right and rotating.

[0103] like Figure 4 The shift control device 300 further includes a power output shaft 341, a power output plate 342, and a hollow pin 343. The power output shaft 341 and the power output plate 342 are connected together by the hollow pin 343. One end of the power output shaft 341 is clamped on the third shift fork 340. Rotating the power output plate 342 clockwise or counterclockwise can control the third shift fork 340 to slide left and right, thereby shifting the third shift gear set 232 to slide left and right on the power output shaft 230.

[0104] (1) Travel speed shifting instructions

[0105] like Figure 512-13 (left, right, front, and back are marked in the figures), the shift shaft 331 is fixed to the speed shift operating shaft 330. When the speed shift operating shaft 330 slides forward, the shift shaft falls into the groove of the first shift fork 310. At this time, the first shift fork 310 is in a neutral position. Clockwise and counterclockwise rotation of the speed shift operating shaft 330 can manipulate the first shift fork 310 to control the first shift gear set 222. Similarly, when the speed shift operating shaft 330 slides backward, the shift shaft falls into the groove of the second shift fork 320. At this time, the second shift fork 320 is in a neutral position. Clockwise and counterclockwise rotation of the speed shift operating shaft 330 can manipulate the second shift fork 320 to control the second shift gear set 223.

[0106] The first shift gear set 222 and the second shift gear set 223 are mounted on the speed change shaft 220 through spline fitting, and the three rotate or stop synchronously.

[0107] The second shift fork 320 controls the second shift gear set 223 to slide leftward, causing its 28T tooth to mesh with the 24T tooth on the first reverse gear set 251, thus engaging the reverse gear. As previously explained, after the engine is running, the first reverse gear set 251 operates synchronously, and after the second shift gear set 223 meshes with it, the speed change shaft 220 begins to operate.

[0108] The second shift fork 320 controls the rightward sliding of the second shift gear set 223, causing its 24T tooth to mesh with the first intermediate gear 262 (19T tooth) on the intermediate shaft 260, resulting in forward 2nd gear. The first shift fork 310 controls the leftward sliding of the first shift gear set 222, causing its 31T tooth to mesh with the second intermediate gear 263 (12T tooth) on the intermediate shaft 260, resulting in forward 1st gear. The first shift fork 310 controls the rightward sliding of the first shift gear set 222, causing its 18T tooth to mesh with the third intermediate gear 264 (25T tooth) on the intermediate shaft 260, resulting in forward 3rd gear. As previously explained, when the engine is running, the intermediate shaft 260 operates synchronously. Once the second shift gear set 223 or the first shift gear set 222 meshes with a gear on the intermediate shaft 260, the speed change shaft 220 begins to operate. After the first shift fork 310 is operated, it needs to be returned to the neutral position before the second shift fork 320 can be operated, and vice versa.

[0109] (2) Instructions for shifting high, medium and low gears

[0110] The auxiliary speed gear set 242 is usually in the low speed gear (right). Pulling the high and low speed pull plate 352 clockwise can manipulate the high and low speed rotating shaft 351 to push the fourth shift fork 350 to control the auxiliary speed gear set 242 to slide to the left, so that it falls into the medium speed gear or the high speed gear.

[0111] First synchronizing gear 241 (gear 13T) and auxiliary speed-change gear set 242 are mounted on rear axle output shaft 240 via a splined fit. All three rotate or stop synchronously. Auxiliary low-speed gear 243 is mounted on the rear axle output shaft via a clearance fit using an oil-free bearing 244. When auxiliary low-speed gear 243 rotates, the rear axle output shaft does not rotate.

[0112] The auxiliary transmission gear set 242 is normally in the low gear position, with the external splines of the auxiliary transmission gear set 242 inserted into the internal splines of the auxiliary low-speed gear 243. At this point, the auxiliary transmission gear set 242 and the auxiliary low-speed gear 243 rotate together through the splined fit, and the rear axle output shaft 240 rotates along with the auxiliary transmission gear set 242. The auxiliary low-speed gear 243, with its 42T teeth, constantly meshes with the first synchronizing gear 241, with its 13T teeth, on the transmission shaft 220. When the transmission shaft 220 rotates, the rear axle output shaft 240 also rotates synchronously. Alternatively, if the fourth shift fork 350 controls the auxiliary transmission gear set 242 to slide leftward, meshing its 20T tooth with the 23T tooth on the transmission shaft 220, a medium gear is achieved; further leftward sliding, meshing its 14T tooth with the 29T tooth on the transmission shaft 220, results in a high gear.

[0113] The second synchronous gear 252 (20T gear) is splined to the front axle output shaft 250, allowing them to rotate or stop synchronously. Because the second synchronous gear 252 (20T gear) is aligned with the first synchronous gear 241 (13T gear) mounted on the rear axle output shaft 240, the front axle output shaft 250 rotates synchronously with the rear axle output shaft 240.

[0114] At this time, the transmission's running speed can be combined with the main transmission and auxiliary transmission to obtain 9 forward gears and 3 reverse gears. The main transmission is forward 1st gear, forward 2nd gear, forward 3rd gear and reverse gear; the auxiliary transmission is low speed gear, medium speed gear and high speed gear.

[0115] like Figure 13-14 As shown, the third shift gear set 232 is mounted on the power output shaft 230 via a splined fit, and both rotate or stop simultaneously. The initial position of the third shift gear set 232 is the first neutral position, with its gears not meshing with other gears. The third shift fork 340 controls the leftward sliding of the third shift gear set 232, causing its internal splines to engage the external splines of the second reverse gear 231. At this point, the two gears rotate synchronously with the power output shaft, and the power output is in reverse gear. As previously explained, after the engine is running, the second reverse gear 231 rotates synchronously, and the power output shaft 230 begins to reverse.

[0116] After the third shift fork 340 controls the third shift gear set 232 to slide rightward to the first neutral position, it then slides rightward further, causing its 24T tooth to mesh with the first intermediate gear 262 (19T tooth) on the intermediate shaft 260, resulting in forward first gear. The third shift fork 340 controls the third shift gear set 232 to slide rightward further to the second neutral position, where it then slides rightward further, causing its 18T tooth to mesh with the third intermediate gear 264 (25T tooth) on the intermediate shaft 260, resulting in forward second gear. As previously explained, when the engine is running, the intermediate shaft 260 operates synchronously. When the third shift gear set 232 meshes with the intermediate shaft 260, the power output shaft outputs forward first and second gears, respectively.

[0117] (4) Front power output shift instructions

[0118] In another embodiment, a front power take-off shaft 270 is further provided, and the front power take-off shaft 270 outputs power to a front PTO position to drive an agricultural implement attached to the front side of the tractor.

[0119] like Figure 17-27 As shown, the third shift gear set 232 is mounted on the power take-off shaft 230 via a splined fit and can slide left and right onto the splined fit and the second reverse gear 231. The third shift fork 340 controls the rightward sliding of the third shift gear set 232 to reach the second neutral position. Further rightward sliding causes its 18T tooth to mesh with the third intermediate gear 264 (25T tooth) on the intermediate shaft 260 (as previously described, this is the second forward gear of the power take-off shaft). At this point, the 18T tooth simultaneously meshes with the third intermediate gear 264 (25T tooth) and gear 27T on the intermediate gear shaft. Since gear 27T meshes with the 17T tooth on the front power take-off gear shaft, the front power take-off gear shaft also rotates simultaneously.

[0120] In a specific embodiment, in order to avoid front and rear power output and simultaneous operation, this solution sacrifices the forward 2nd gear output of the power output shaft 260, which is engaged between the 18T tooth in the third shift gear set 232 and the third intermediate gear 264 (25T tooth) of the intermediate shaft 260. That is, the right end of the power output shaft 230 is splined and replaced with an external spline sleeve 233 with a clearance fit. Therefore, the power output shaft 230 does not rotate, and the 18T tooth gear is engaged with the 27T tooth gear, which ultimately drives the front power output shaft 270 to rotate and output power to the front PTO position.

[0121] Since the rear power output shaft is at the bottom of the gearbox and is immersed in the gearbox oil, when the external spline sleeve 271 and the second reverse gear 231 are clearance-fitted with the power output shaft 230, standard lubrication parts such as needle bearings or oil-free bearings are not required.

[0122] like Figure 22-26As shown, when the tractor begins to operate, the third shift fork 340 of the power output is generally in the neutral position 1. At this time, the internal splines of the third shift gear set 232 are not in contact with the reverse gear 2, and the gears of the third shift gear set 232 are not engaged with other gears. Therefore, the power output shaft and the front power output shaft do not operate.

[0123] like Figure 22 As shown, the third shift fork 340 is moved forward to the rear PTO reverse position. At this time, half of the internal spline of the shift gear 18 / 24T is engaged with the external spline of the second reverse gear, and the other half of the internal spline is mounted on the spline of the power output shaft. Since the second reverse gear has been running since the engine started, the power output shaft begins to reverse under the action of the spline fit. The forward and reverse rotation of the present utility model are relative to the power input gear shaft, that is, the power input gear shaft (15T helical gear) rotates forward, the power is transmitted to the helical gear 28 and the intermediate gear shaft (19T) in reverse, the power is transmitted to the reverse gear 1 (21 / 24T) in forward rotation, the power is transmitted to the second reverse gear in reverse rotation, and the rear axle output shaft that rotates with the second reverse gear also reverses.

[0124] like Figure 23-24 As shown, shift the gear back to the Neutral 1 position, then move the shift fork back to the rear PTO forward position. At this point, the 24T tooth on the shift gear 18 / 24T meshes with the 19T tooth on the intermediate gear shaft. After the engine starts, the intermediate gear shaft continues to rotate, and the shift gear 18 / 24T, meshing with its 19T tooth, begins to rotate. Since the shift gear 18 / 24T is now mounted on the power output shaft via a spline fit, the power output shaft also begins to rotate forward. Relative to the power input gear shaft, that is, the power input gear shaft (15T helical teeth) rotates forward, power is transmitted to the helical gear 28 and the intermediate gear shaft (19T), counterclockwise, and then transmitted to the shift gear 18 / 24T, which rotates forward. The rear axle output shaft, which rotates in conjunction with the shift gear 18 / 24T, also rotates forward.

[0125] like Figure 25 As shown, move the shift fork backward to the neutral position 2. At this time, the internal spline of the shift gear 18 / 24T is not in contact with the reverse gear 2, and its 18 / 24T teeth are not engaged with other gears, so the rear power output shaft does not rotate.

[0126] like Figure 26As shown, move the shift fork backward to the front PTO position. At this point, the 18T tooth of shift gear 18 / 24T meshes simultaneously with the 25T tooth on the intermediate gear shaft and gear 27T. After the engine is started, the intermediate gear shaft continues to rotate, driving the shift gear 18 / 24T meshing with its 25T tooth, which in turn drives gear 27T. Because gear 27T meshes with the 17T tooth on the front PTO gear shaft, the front PTO gear shaft also rotates. At this point, the rear PTO shaft does not rotate because the internal spline of shift gear 18 / 24T is fully seated on the external spline sleeve, which has a clearance fit with the rear PTO shaft.

[0127] Relative to the power input gear shaft, that is, the power input gear shaft (15T helical gear) rotates forward, the power is transmitted to the helical gear 28 and the intermediate gear shaft (25T) in reverse, transmitted to the shift gear 18 / 24T in forward rotation, transmitted to the gear 27T in reverse rotation, and transmitted to the front power output gear shaft (17T) in forward rotation.

[0128] like Figure 27 As shown, if the front PTO needs to rotate in reverse (relative to the power input gear shaft), this can be achieved by adding a third reverse gear set 274. This third reverse gear set 274 comprises a pair of 12 / 16T toothed interlocking gears mounted on the gear shaft (gear shafts 12 / 16T). Operation up to gear 27T is identical to the forward rotation of the front PTO output. Then, gear 27T meshes with the 16T teeth of gear shaft 12 / 16T, causing gear shaft 12 / 16T to rotate. Simultaneously, the 12T teeth of gear shaft 12 / 16T mesh with gear 21T, causing gear 21T to rotate. Because the teeth of gear 21T are splined to the front PTO shaft, the front PTO shaft rotates simultaneously.

[0129] Relative to the power input gear shaft, that is, the power input gear shaft (15T helical gear) rotates forward, the power is transmitted to the helical gear 28 and the intermediate gear shaft (25T) in reverse, transmitted to the shift gear 18 / 24T in forward rotation, transmitted to the gear 27T in reverse rotation, transmitted to the gear shaft 12 / 16T in forward rotation, and transmitted to the gear 21T and the front power output shaft in reverse rotation.

[0130] Finally, whether it is the front power output or the rear power output, it is connected to the machinery required for agricultural operations through parts such as spline sleeves, universal joints, and spline shafts to provide a power source for the agricultural machinery.

[0131] like Figure 14-16 As shown, the shift forks include a first shift fork 310, a second shift fork 320, a third shift fork 340 and a fourth shift fork 350. The shift forks are respectively fixed on the fork shafts with clearance fit, namely the first fork shaft 311, the second fork shaft 321, the third fork shaft 344 and the fourth fork shaft 353.

[0132] Taking the first shift fork 310 and the second shift fork 320 as an example, the first shift fork shaft 311 and the second shift fork shaft 321 are respectively installed in the transmission case through clearance fit and are fixed and cannot move axially.

[0133] The first shift fork 310 is equipped with a sleeve 312, which is mounted on the first shift fork shaft 311 with a clearance fit, allowing the first shift fork shaft 311 to slide within the sleeve 312. The first shift fork shaft 311 has three shift slots 313. A steel ball 314 is positioned in one of the shift slots 313 of the first shift fork shaft 311 due to the elastic force of a compression spring 315. Due to the spring force, only a significant torque can push the first shift fork 310 to force the steel ball into another shift slot, completing the shift.

[0134] The second shift fork 320 has a similar shifting mechanism to the first shift fork 310, respectively shifting the first shift gear set 222 and the second shift gear set 223, which are mounted on the speed shift shaft 220. The first and second shift fork shafts 311 and 321 are arranged parallel to each other, with a space between them. A shift shaft 331 is inserted into this space. The second shift fork 320 and the first shift fork 310 have shifting slots positioned opposite each other, with one end of the shift shaft 331 inserted into the slots. The shift shaft 331 controls the first and second shift forks 310 and 320, respectively. Specifically, the speed shift operating shaft 330 is capable of both lateral movement and rotation. When the speed shift operating shaft 330 moves laterally, the gear shift shaft 331 is switched to the shifting groove of the second shift fork 320 or the first shift fork 310, and then the speed shift operating shaft 330 is rotated so that there is a component of left and right movement at the end of the gear shift shaft 331, which shifts the second shift fork 320 or the first shift fork 310 to shift gears. Therefore, one shaft realizes the movement and shifting of multiple shift forks.

[0135] In order to ensure the stability of gear shifting, a baffle 334 is set at the edge of the moving range of the gear shift shaft 331. The baffle 334 is fixed to the gearbox body 110 or the upper cover 120, and has a through hole in the middle. The gear shift shaft 331 moves in the through hole and is restricted by the edge of the through hole.

[0136] Taking the third shift fork 340 as an example, the third shift fork 340 includes a third shift fork shaft 344, a steel ball 314, and a compression spring 315. The steel ball 314 and compression spring 315 are mounted within the third shift fork 340 and engage with grooves provided on the third shift fork shaft 344 to limit the position of the third shift fork 340. Specifically, the third shift fork shaft 344 is provided with a reverse stop groove 3441, a first neutral groove 3442, a first forward stop groove 3443, a second neutral groove 3444, and a second forward groove 3445 in this order.

[0137] The third shift fork 340 is clamped on the third shift gear set 232 and can be controlled to slide on the power output shaft 230 to achieve five gear positions: reverse gear, first neutral, forward gear 1, second neutral, and forward gear 2. Therefore, there are five grooves on the third shift fork shaft 344 that slide left and right, representing the five gear positions. The steel ball falls into the five grooves on the third shift fork shaft 344 due to the elastic force of the compression spring: the reverse gear groove 3441, the first neutral groove 3442, the first forward gear groove 3443, the second neutral groove 3444, and the second forward groove 3445, thereby achieving physical control of the five gear positions of the power output shaft 230: reverse gear, first neutral, forward gear 1, second neutral, and forward gear 2. Due to the elastic force, only a larger torque can push the third shift fork 340 to drive the steel ball to fall into another groove, completing the gear shift. The specific action is to twist the power output pull plate 342, so that the power output pull plate 342 swings around the hollow pin 343 and drives the hollow pin 343 to rotate, thereby transmitting power to the power output shaft 341 connected to the other end of the hollow pin 343, so that the power output shaft 341 shifts the three-speed shift fork 340, thereby realizing the movement of the three-speed shift fork 340 on the five gears of the third fork shaft 344, thereby realizing the control of the five gears.

Claims

1. A gearbox capable of outputting power forward and backward, comprising a housing (110), an input shaft (210) for inputting engine power and an input main gear (212) fixed thereon, characterized in that: A speed change shaft (220) is arranged upwardly from the axis of the input shaft (210), and a slave shift mechanism and a secondary master shift gear set are sequentially arranged on the speed change shaft (220); The invention comprises an intermediate shaft (260), wherein the intermediate shaft (260) is fixed with an input slave gear (261) meshing with an input main gear (212) and is provided with a main shift gear set, wherein the slave shift mechanism slides to different positions and meshes with gears of different numbers of teeth of the main shift gear set to achieve main speed change; a rear axle output shaft (240) is provided on the coaxial center line of the intermediate shaft (260), wherein the rear axle output shaft (240) is provided with a slave shift mechanism, wherein the slave shift mechanism can slide left and right on the rear axle output shaft and cooperate with the slave main shift gear set to achieve slave speed change; The first reverse gear set (251) includes a first gear and a second gear that rotate synchronously, the first gear meshes with the main shift gear set, and the slave shift mechanism slides to mesh with the second gear to achieve reverse gear shift of the main speed change; The power output shaft (230) comprises a third shifting gear set (232) and a second reverse gear (231), wherein the second reverse gear (231) is loosely sleeved on the power output shaft (230) and meshes with the second gear of the first reverse gear set (251) and rotates idly, and the third shifting gear set (232) slides on the power output shaft (230) and meshes with the main shifting gear set and is in transmission connection with the second reverse gear (231), thereby realizing the shifting of the power output shaft (230); The front power output shaft (270) includes a front power gear (273), and the front power gear (273) is transmission-connected to a transmission position of a third shift gear set (232); the third shift gear set (232) drives the front power output shaft (270) to output power.

2. A gearbox capable of outputting power to the front and rear according to claim 1, characterized in that: A positioning shaft (271) is provided on the lower side of the housing (110), and a positioning shaft gear (272) is provided on the positioning shaft (271). The positioning shaft gear (272) is meshed with a transmission position of the third shift gear set (232) for transmission, and the positioning shaft gear (272) is meshed with the front power gear (273) for transmission.

3. A gearbox capable of outputting power to the front and rear according to claim 2, characterized in that: The positioning shaft (271) is installed in the transmission case through clearance fit, with one end positioned by the shaft hole of the transmission case and the other end positioned by the end face of the transmission case front cover.

4. A gearbox capable of outputting power to the front and rear according to claim 2, characterized in that: The inner hole of the positioning shaft gear (272) is fitted with a bearing through clearance, and the inner hole of the bearing is mounted on the positioning shaft (271).

5. The gearbox capable of outputting power to the front and rear according to claim 2, characterized in that: The power output shaft (230) is provided with a clearance-fitted external spline sleeve (233) and a fixedly connected external spline; one side of the second reversing gear (231) is provided with a gear external spline; the third shift gear set (232) is provided with an internal spline; the third shift gear set (232) slides, and the internal spline is sequentially connected with the external spline, the external spline sleeve, and the gear external spline; at the position where the third shift gear set (232) is connected to the external spline sleeve, the third shift gear set (232) is meshed with the main shift gear set and the positioning shaft gear (272).

6. A gearbox capable of outputting power to the front and rear according to any one of claims 1 to 5, characterized in that: The invention comprises a front axle output shaft (250), wherein the front axle output shaft (250) is on a different axis from the speed change shaft (220) and the intermediate shaft (260); the first reversing gear set (251) is loosely sleeved on the front axle output shaft (250) and can rotate idly; a second synchronous gear (252) is fixed on the front axle output shaft (250); the rear axle output shaft (240) is transmission-connected with a first synchronous gear (241); the first synchronous gear (241) and the second synchronous gear (252) are meshed and transmitted, so that the front axle output shaft (250) and the rear axle output shaft (240) rotate synchronously.

7. A gearbox capable of outputting power to the front and rear according to any one of claims 1 to 5, characterized in that: The auxiliary slave shift mechanism comprises an auxiliary speed gear set (242) and an auxiliary low-speed gear (243), wherein the auxiliary low-speed gear (243) is loosely sleeved on the rear axle output shaft (240) and is provided with an internal spline, and the auxiliary speed gear set (242) is provided with an external spline and is transmission-connected to the rear axle output shaft (240) and can slide leftward and rightward; the auxiliary master shift gear set comprises a high-speed gear (224), a medium-speed gear (226) and a low-speed gear (225) fixedly connected to the speed shaft (220) and arranged in sequence to the left, and the low-speed gear (225) is meshed with the auxiliary low-speed gear (243); the auxiliary speed gear set (242) slides and meshes with the high-speed gear (224) and the medium-speed gear (226) in sequence and can slide to the left spline of the auxiliary speed gear set (242) and the right spline of the auxiliary low-speed gear (243) for transmission, thereby realizing high, medium and low speed conversion.

8. The gearbox capable of outputting power to the front and rear according to claim 7, characterized in that: The slave shift mechanism comprises a first shift gear set (222) and a second shift gear set (223); the master shift gear set comprises a first intermediate gear (262), a second intermediate gear (263) and a third intermediate gear (264); gear 1 of the first reverse gear set (251) meshes with the first intermediate gear (262); sliding the first shift gear set (222) left and right enables meshing with the second intermediate gear (263) and the third intermediate gear (264) to achieve first and third gear shifts; sliding the second shift gear set (223) enables meshing with the first intermediate gear (262) to achieve second gear shifts; sliding the second shift gear set (223) enables meshing with gear 2 of the first reverse gear set (251) to achieve reverse gear shifts; the first shift gear set (222) and the second shift gear set (223) are respectively provided with a neutral position.

9. The gearbox capable of outputting power to the front and rear according to claim 6, characterized in that: The projections of the axis center line of the power output shaft (230) and the axis center lines of the first reversing gear set (251), the speed change shaft (220), and the intermediate shaft (260) are arranged on the four vertices of the quadrilateral.

10. The gearbox capable of outputting power to the front and rear according to claim 8, characterized in that: The invention comprises a shift operating device (300), wherein the shift operating device (300) comprises a first shift fork (310), a second shift fork (320), a third shift fork (340) and a fourth shift fork (350), wherein the first shift fork (310) shifts the first shift gear set (222) to slide, the second shift fork (320) shifts the second shift gear set (223) to slide, the third shift fork (340) shifts the third shift gear set (232) to slide, and the fourth shift fork (350) shifts the auxiliary speed gear set (242) to slide.

11. The gearbox capable of outputting power to the front and rear according to claim 6, characterized in that: The housing (110) further comprises a left end cover (130) and a support plate (111); one end of the input shaft (210), the intermediate shaft (260), the front axle output shaft (250), and the power output shaft (230) are fixed to the left end cover (130) via bearings; the other ends of the intermediate shaft (260), the front axle output shaft (250), the power output shaft (230), one end of the rear axle output shaft (240), and the speed change shaft (220) are connected to the support plate (111) via bearings; a mounting hole is provided at the left end of the input shaft (210); the right end of the speed change shaft (220) is inserted into the mounting hole; and a first end connecting bearing (211) is provided between the two shafts.

12. The gearbox capable of outputting power to the front and rear according to claim 1, characterized in that: It comprises a gearbox lower cover (160), wherein the front power output shaft (270) is fixed in the gearbox lower cover (160) via a bearing.

13. A small agricultural tractor comprising the gearbox capable of outputting power to the front and rear according to any one of claims 1 to 11, characterized in that: It comprises front and rear mounting positions, and the front and rear mounted agricultural implements can be transmission-connected to the front power output shaft (270) and the power output shaft (230).

Images