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

Abstract

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

[0002] Tractors are usually used as power devices, and are used to carry agricultural machinery and implements. The front power output of the tractor can be used to carry agricultural machinery and implements such as bulldozers, snowplows, and lawn mowers; the rear power output of the tractor can be used to carry agricultural machinery and implements such as trenchers, rotary tillers, and potato harvesters. Generally, high-horsepower tractors are large in size and space, so they can be designed with front and rear power output devices; while low-horsepower tractors are small in size and space, so they only have rear power output, which means that agricultural machinery and implements can only be hung 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 continuously variable 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 not worth the cost to use it on small agricultural machinery four-wheel tractors. Fig.29 As shown, Chinese patent CN206708343U, the patent name is "a gearbox particularly suitable for agricultural machinery", discloses a gearbox that realizes forward and backward switching through a forward and reverse switching control device, thereby realizing forward and reverse multi-gear switching. The forward and reverse switching control device includes a wet dual clutch, which increases the manufacturing cost and maintenance cost, and the input shaft, speed change shaft, gear transmission shaft, clutch support shaft and output driven steering shaft of the gearbox are almost lined up. Although the sensitivity of the gear switching is guaranteed, the standing space is large, the gear shifting efficiency is low, and the manufacturing cost and use cost are still high. Chinese patent CN218294341U discloses "a transmission system for agricultural machinery", and the fifth gear set on the third shaft is respectively meshed with the fourth gear, the sixth gear, and the seventh gear to realize the three forward gears, and the fifth gear is meshed with the tenth gear to realize the reverse gear. Although the transmission system realizes the setting of three forward gears and one reverse gear in the case of three shafts, it avoids the problem of greatly increasing the volume of the transmission system. However, three gears cannot meet the use requirements of current agricultural tractor 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, land preparation, sowing, and transportation, and it is also necessary to control the operation to be convenient and low-cost, which itself has contradictory problems in technology. The setting of the shifting structure for agricultural tractors has always troubled the progress of tractor technology, and is also a difficult problem that the present invention needs to overcome. Chinese patent CN115489301A discloses "a tractor transmission system and a tractor", which uses an independent shuttle gear on the clutch assembly to operate the shifting, and sets two shift forks on the same fork shaft to perform forward and backward shifting, and the shifting logic is clear. However, the two forks are highly correlated with each other, and the fluctuation transformation spacing requirement is high, which cannot meet the working requirements of most gearboxes.

[0005] The invention aims to design a small-horsepower wheeled tractor gearbox for 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 view of the problem of complex transmission mechanism in the above-mentioned prior art, the present invention 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 present invention also provides a small agricultural tractor, which is more flexible to use on tractors of 35 horsepower or less.

[0007] According to the present invention, there is provided a gearbox capable of outputting power forward and backward, 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 arranged upwardly from the axis of the input shaft, and a slave shift mechanism and a slave main shift gear set are arranged on the speed change shaft in sequence; It comprises an intermediate shaft, the intermediate shaft is fixed with an input slave gear meshing with the input main gear and is provided with a main shift gear set, the slave shift mechanism slides to different positions and meshes with gears with different numbers of teeth of the main shift gear set to achieve main speed change; the intermediate shaft is provided with a rear axle output shaft on the same axis, the rear axle output shaft is provided with a secondary slave shift mechanism, the secondary slave shift mechanism can slide left and right on the rear axle output shaft and cooperate with the secondary main shift gear set to achieve secondary speed change; It comprises a first reverse gear set, wherein the first reverse gear set comprises a synchronously rotating gear 1 and a gear 2, wherein the gear 1 is meshed with the main shift gear set, and the slave shift mechanism slides to mesh with the gear 2 to realize the reverse gear shift of the main speed change; It comprises a power output shaft, the power output shaft is provided with a third shifting 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 shifting gear set slides on the power output shaft and meshes with the main shifting gear set in turn and is transmission-connected with the second reverse gear, so as to achieve the shifting of the power output shaft output power; It comprises a front power output shaft, the front power output shaft comprises a front power gear, the front power gear is transmission-connected with a transmission position of a third shift gear set; the third shift gear set drives the front power output shaft to output power.

[0008] The present invention realizes multi-speed shifting through the cooperation of the input shaft, the speed-changing shaft, the intermediate shaft, the reverse gear set and the reasonable layout of the gear shaft. The intermediate shaft is used to transmit the power to the speed-changing shaft, the power output shaft and the reverse gear set. One shaft has multiple transmissions, which greatly reduces the space of the gear box and enables the gear box to be miniaturized. At the same time, the cooperation of the front power output shaft and the power output shaft realizes the output of the front and rear power, and the power output is richer.

[0009] Preferably, a positioning shaft is provided on the lower side of the housing, a positioning gear is provided on the positioning shaft, the positioning gear is meshed with a transmission position of the third shift gear set for transmission, and the positioning gear is meshed with the front power gear for transmission.

[0010] The positioning shaft of the present invention is arranged at the bottom of the box body and then transmitted to the front power output shaft, so that the optional setting of the front power output is more convenient and the stability of the output power is guaranteed.

[0011] Preferably, the positioning shaft is installed in the gearbox body through clearance fit, one end of which is positioned by the shaft hole of the gearbox body, and the other end is positioned by the end surface of the gearbox front cover. The present invention facilitates the installation and fixation of the positioning shaft.

[0012] Preferably, the inner hole of the positioning shaft gear is equipped with a bearing through a clearance fit, and the inner hole of the bearing is mounted on the positioning shaft.

[0013] Preferably, the power output shaft is provided with an external spline sleeve with clearance fit and an external spline fixedly connected, the second reversing gear is provided with an external spline of a gear on one side, the third shift gear set is provided with an internal spline, the third shift gear set slides, the internal spline is respectively connected with the external spline, the external spline sleeve, and the external spline of the gear in sequence, and at the position where the third shift gear set is connected with the external spline sleeve, the third shift gear set is respectively meshed with the main shift gear set and the positioning gear. The present invention avoids the simultaneous output of front and rear power through the provision of an external spline sleeve, reduces the excessive distribution of power output, and avoids idling of mounted agricultural implements.

[0014] 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 idly 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 connected with a first synchronous gear, the first synchronous gear and the second synchronous gear are meshed and driven so that the front axle output shaft and the rear axle output shaft rotate synchronously. The front axle output shaft of the present invention can output front wheel drive, and at the same time, it serves as a support shaft of the first reversing gear set, thereby realizing the installation of the first reversing gear set, one shaft has multiple uses, saves space in the gear box, and reduces costs.

[0015] 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 cooperate with the right spline of the auxiliary low-speed gear for transmission, thereby realizing high, medium and low speed conversion.

[0016] Preferably, the slave shift mechanism includes a first shift gear group and a second shift gear group, the main shift gear group includes a first intermediate gear, a second intermediate gear and a third intermediate gear, gear 1 of the first reversing gear group is meshed with the first intermediate gear, sliding the first shift gear group 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 group can mesh with the first intermediate gear to achieve second gear shifting, sliding the second shift gear group can mesh with gear 2 of the first reversing gear group to achieve reverse gear shifting, and the first shift gear group and the second shift gear group are respectively provided with a neutral position.

[0017] Preferably, the projections of the axis center line of the power output shaft and the axis center lines of the shafts where the first reversing gear set, the speed change shaft and the intermediate shaft are located are arranged on the four vertices of a quadrilateral.

[0018] 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.

[0019] Preferably, the housing further comprises a left end cover and a support plate, the input shaft, the intermediate shaft, the front axle output shaft and one end of the power output shaft are fixed on the left end cover via 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 via bearings, a mounting hole is arranged 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 arranged between the two shafts.

[0020] 12. A gearbox capable of outputting power forward and backward according to claim 1, characterized in that it comprises a gearbox lower cover, and the front power output shaft is fixed in the gearbox lower cover through a bearing.

[0021] The present invention also provides a small agricultural tractor, comprising the gearbox capable of outputting power frontally and rearwardly, and also comprising front and rear mounting positions, and the front and rear mounted agricultural implements can be drivingly connected with the front power output shaft and the power output shaft. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Schematic diagram of the gearbox structure of the embodiment; Figure 2 It is a right view of the gearbox of the embodiment; Figure 3 It is a schematic diagram of the structure of the transmission of the embodiment from the right rear side; Figure 4 It is a schematic diagram of the structure of the transmission of the embodiment from the right side; Figure 5 This is a partial disassembly diagram of the transmission of the embodiment; Figure 6 It is a schematic front view of the gear and shaft structure of the transmission of the embodiment; Figure 7 It is a rear view schematic diagram of the gear and shaft structure of the transmission of the embodiment; Figure 8 This is a schematic diagram of the matching relationship between some gears and shaft structures of the transmission of the embodiment; Fig. 9 for Figure 8 Partial cross-sectional view of the middle A part; Fig.10 for Figure 8 Partial cross-sectional view of the middle B part; Fig.11 for Figure 8 Partial cross-sectional view of the middle C section; Fig.12 for Figure 8 Partial cross-sectional view of the middle D section; Fig.13 The structure of the transmission speed change system of the embodiment is intended; Fig.14 It is a schematic diagram of the gear matching relationship between the intermediate shaft and the power output shaft; Fig.15 is a schematic diagram of the structure of the third shift fork in the embodiment; Fig.16 It is a schematic diagram of the gearbox structure; Fig.17 This is a schematic diagram of the front and rear output power gearbox structure of another embodiment; Fig.18 This is a schematic diagram of the gear-shaft matching structure of another embodiment; Fig.19 This is a schematic diagram of the back structure of the gear-shaft matching of another embodiment; Fig. 20 This is a schematic diagram of the power output shaft structure of another embodiment; Fig.21 This is a schematic diagram of the positioning shaft structure of another embodiment; Fig. 22 This is a schematic diagram of the structure of the PTO reverse position in another embodiment; Fig.23 It is a schematic diagram of the neutral position structure of another embodiment; Fig.24 This is a schematic diagram of the structure of the PTO forward rotation position after another embodiment; Fig.25 It is a schematic diagram of the neutral 2 position structure of another embodiment; Fig.26 This is a schematic diagram of the PTO position structure of another embodiment; Fig. 27 An embodiment of the front PTO position reversal; Fig.28 A tractor according to the present invention; Fig.29 Attached figure is the background technology scheme.

[0023] The figure is marked as: 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.

[0024] 200-transmission gear assembly, 210-input shaft, 211-first end connecting bearing, 212-input main gear, 220-speed shaft, 221-first spline shaft, 222-first shift gear set, 223-second shift gear set, 224-high speed gear, 225-low speed gear, 226-medium speed gear; 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.

[0025] 270-front power output shaft, 271-positioning shaft, 272-positioning shaft gear, 273-front power gear, 274-third reverse gear set; 300-shift operating device, 310-first shift fork, 311-first fork shaft, 312-sleeve, 313-shift slot, 314-steel ball, 315-compression spring, 320-second shift fork, 321-second fork shaft, 330-speed operating shaft, 331-gear shift shaft, 332-fixing sleeve, 333-reset 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.

[0026] 401- first axis space; 402- second axis space; 403- third axis space; 404- fourth axis space. DETAILED DESCRIPTION

[0027] In order to further understand the content of the present invention, the present invention is described in detail in conjunction with the accompanying drawings and embodiments. It should be understood that the embodiments are only for explaining the present invention and are not intended to limit it.

[0028] 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, rather than indicating or implying 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 limiting the present invention.

[0029] In addition, the terms "first" and "second" are used for descriptive purposes only and should not 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" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, the meaning of "plurality" is two or more, unless otherwise clearly defined.

[0030] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can also be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0031] In the present invention, unless otherwise clearly stated and defined, the term NT-tooth gear is used, and N is the number of teeth.

[0032] like Figure 1-Figure 2 As shown, the present invention provides a tractor transmission, including a transmission 100, wherein the transmission 100 includes a transmission body 110, a transmission upper cover 120, a left end cover 130, a bottom cover, and a connecting box 150. Fig.28 The tractor of the present invention is shown, which includes the above-mentioned tractor transmission and a gear shifting structure.

[0033] Another embodiment is Fig.17 As shown, the gearbox 100 further includes a gearbox lower cover 160 , and the gearbox lower cover 160 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 .

[0034] The cavity formed by the gearbox body 110, the gearbox upper cover 120, the gearbox end cover 130, the bottom cover and the connecting box body 150 is provided with a transmission gear assembly 200, and the transmission gear assembly 200 includes a shaft, a gear, and necessary supporting bearings. The bearings are generally supported and fixed by structural parts such as partitions provided inside the gearbox 100. The tractor transmission also includes a shift operating device 300, which adjusts the combination relationship between gears by toggling the transmission gear assembly 200 to achieve high and low front and back gear changes.

[0035] 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 output shaft 270 is also included.

[0036] 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 the input shaft 210. 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 protrudingly provided 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, the "connection" includes direct connection and indirect connection. The end of the input shaft 210 is directly connected to the engine 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. The input main gear 212 in this embodiment is a 15T helical gear.

[0037] 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 , Fig.16 As shown, a support plate 111 is provided in the gearbox body 110, a support bearing seat 112 is provided on the support plate 111, a bearing on the speed change shaft 220 is fixed on the support bearing seat 112, and another bearing is provided at the outer end (left end) of the speed change shaft 220 and fixed on the connecting box body 150. The support plate, the bearing seat and the gearbox are integrated.

[0038] 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, and the two are on the same axis, that is, the axis center lines of the two shafts coincide, and the two shafts are defined as a first axis center line space 401. The left end of the speed change shaft 220 is connected to the right end of the input shaft 210 through a first end connecting bearing 211. Fig. 9As shown, a mounting hole is set 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, and a first end connecting bearing 211 is set 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, and the two do not interfere with each other in rotation, and can support each other, so that the two shafts are fixed more firmly and stably. Of course, the right end of the speed change shaft 220 can also be provided with a mounting hole for a needle bearing, and the needle bearing can be set in the mounting hole. The first end connecting bearing 211 can be a needle bearing, which can save space, and of course it can also be replaced by other bearings such as graphite bearings.

[0039] 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 connection. 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 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 a specific embodiment, the first shift gear set 222 includes a 31T gear and a 18T gear, the two gears are linked and there is a shift fork between them; the second shift gear set 223 includes a 28T gear and a 24T gear, the two gears are linked and there is a shift fork between them. The speed change shaft 220 is driven and fixedly connected to the high-speed gear 224, the medium-speed gear 226 and the low-speed gear 225 in sequence to the left on the left side of the support plate 111 to form a secondary main shift gear set. The secondary main shift gear set cooperates with the secondary slave shift mechanism to realize the secondary speed change. In a specific embodiment, the high-speed gear 224 is a 29T gear, the medium-speed gear 226 is a 23T gear, and the low-speed gear 225 is a 13T gear. The 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 change shaft 220, forming 12 gears.

[0040] The front axle output shaft 250 is supported by two bearings and installed in the gearbox 100. The front axle output shaft 250 is parallel to the input shaft 210 and the speed change shaft 220, and is defined as the second axis centerline space 402. The two bearings can be fixed on the support plate 111 and the left end cover 130 respectively. One end of the front axle output shaft 250 extends out of the left end cover 130 to form an output end. Therefore, an output bearing seat 132 can be set at the right end of the left end cover 130, and structures such as reinforcing ribs can be set.

[0041] The first reversing gear set 251 is set in an empty sleeve on the front axle output shaft 250. The first reversing gear set 251 is installed on the front axle output shaft 250 through two needle bearings with clearance fit and fixed with a shaft retaining ring to prevent it from sliding. Specifically, the first reversing gear set 251 can be installed 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 gear and a 21T 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 gear. The front axle output shaft 250 realizes synchronous rotation 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 realize both front driving force output and gear reversal, realizing multiple uses of one shaft and one gear, simplifying the gearbox structure and improving mechanical efficiency and service life.

[0042] 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 arranged between the two bearings. As shown in Figures 12-13, the power output shaft 230 is supported by two bearings and parallel to the input shaft 210 and the front axle output shaft 250, and the third axis centerline space 403 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 arranged between the two bearings. Fig.10 As shown, the second reverse gear 231 is installed on the power output shaft 230 through clearance fit (empty 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.

[0043] The third shift gear set 232 is installed on the power output shaft 230 through a spline matching transmission. The third shift gear set 232 includes a 24T gear and an 18T gear, and a shift fork is positioned between the two gears. The third shift fork 340 is clamped on the third shift gear set 232 to control it to slide left and right on the power output shaft 230. The right end of the power output shaft 230 shown is a spline, and the power can be output through a spline sleeve, a universal joint or a spline shaft. The power output shaft 230 shown is used to drive the agricultural implements mounted on the agricultural vehicle, providing independent drive for the agricultural implements.

[0044] According to the needs of agricultural tractors, when the tractor is equipped with front and rear agricultural implements, front and rear PTO connection positions (power take-off devices) are required to connect agricultural implements and output power. Since there are many agricultural implements mounted at the rear of the tractor and it is more common, the power take-off shaft 230 is generally connected to the rear PTO position.

[0045] If front mounting is required, in another embodiment, Figure 17-27 As shown, a front power output shaft 270 may be provided, and the front power output shaft 270 is connected to the front PTO position through gear meshing with the gears provided on the power output shaft 230, so that power can be output both frontally and rearwardly.

[0046] In some specific embodiments, the front power output shaft 270 is arranged on the gearbox lower cover 160, and 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.

[0047] like Fig.21 As shown, a positioning shaft 271 gear transmission is arranged between the power output shaft 230 and the front power output shaft 270. The positioning shaft 271 is installed in the gearbox body through clearance fit, one end of which is positioned by the shaft hole of the gearbox body, and the other end is positioned by the end face of the gearbox front cover (left end cover). The positioning shaft 271 is provided with a positioning shaft gear 2722, which is a 27T gear, and a deep groove ball bearing is installed in its inner hole through clearance fit, and the inner hole of the bearing is installed on the positioning shaft 270. The 27T gear is fixed in the gearbox body through a friction-reducing gasket and a bearing end face, and can rotate around the positioning shaft.

[0048] 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.

[0049] The third shift gear set 232 includes a 24T gear and a 18T gear. When the third shift fork 340 is shifted, the 18T gear is meshed with the third intermediate gear 264 (25T gear) and the 27T gear on the intermediate gear shaft. After the engine is started, the intermediate shaft 260 continues to operate, driving the third shift gear set 232 meshing with its 25T gear to operate, and the third shift gear set 232 in turn drives the positioning shaft gear 272 to operate.

[0050] Since the gear 27T is meshed with the front power gear 273 on the front power output shaft 270, the front power output shaft 270 also runs simultaneously. Generally, a spline is provided at the end of the front power output shaft 270, and the power can be transmitted to the front mounted agricultural implement through the existing transmission structure.

[0051] In order to prevent the power output shaft 230 and the front power output shaft 270 from running at the same time, when the third shift gear set 232 is in the position where the positioning shaft gear 272 is matched, the power output shaft 230 is provided with an outer spline sleeve 233 with clearance fit and an outer spline 234 that is fixedly connected, that is, the right end of the power output shaft 230 is a spline, which is replaced with an outer spline sleeve 233 with clearance fit with the power output shaft 230, while the left end is still a fixedly connected outer spline 234. The outer spline sleeve 233 has no power transmission with the power output shaft 230, and is connected to the inner spline sleeve of the third shift gear set 232. Since the inner spline of the third shift gear set 232 is completely located on the outer spline sleeve 233, when the outer spline sleeve 233 and the power output shaft 230 are in a clearance fit, the power output shaft 230 does not operate and transmit.

[0052] At this time, the outer spline sleeve 233 and the second reverse gear 231 are installed on the power output shaft 230 through clearance fit, and the power output shaft 230 does not rotate when the outer spline sleeve 233 and the second reverse gear 231 are running. The parameters of the outer spline of the outer spline sleeve 233, the spline of the power output shaft 230 and the outer spline of the second reverse gear 231 are the same.

[0053] like Figure 3-8 As shown in Figures 1 and 12, the rear axle output shaft 240 is supported by bearings at both ends and installed in the gearbox body 110 and the rear axle gearbox body. A specific solution is that the bearing support at one end of the rear axle output shaft 240 is fixed on the support plate 111, and the bearing at the other end, i.e., the output end, is fixed on the rear axle gearbox body. 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 output shaft 230, and is outside the plane formed by any two axis centers, which is defined as the fourth axis centerline space 404.

[0054] The first synchronous gear 241 is mounted on the rear axle output shaft 240 through spline fitting and fixed with a shaft retaining ring and a bearing to prevent it from sliding. The first synchronous gear 241 is a 13T gear. The first synchronous gear 241 is meshed with the second synchronous gear 252 to synchronize the output rotation of the rear axle output shaft 240 with the front axle output shaft 250, so that the agricultural vehicle can achieve four-wheel drive.

[0055] The rear axle output shaft 240 is provided with a secondary slave shift mechanism, which slides on the rear axle output shaft 240 to achieve transmission. A common installation method is that the rear axle output shaft 240 is provided with a spline shaft, the secondary slave shift mechanism is provided with a spline fit, and the secondary slave shift mechanism slides on the rear axle output shaft 240 and can transmit. The secondary slave shift mechanism slides left and right to mesh with the secondary main shift gear set to achieve secondary speed change.

[0056] The auxiliary slave shift mechanism includes an auxiliary speed gear set 242, which is mounted on the rear axle output shaft 240 through a spline fit. The fourth shift fork 350 is clamped on the auxiliary speed gear set 242 to control it to slide left and right on the rear axle output shaft 240. The auxiliary speed gear set 242 includes a 20T gear and a 14T gear. The two gears are fixedly connected and can be linked, and a shift fork clamp is provided between them. The high and low speed rotating shaft 351 and the high and low speed pull plate 352 are connected together through a hollow pin. One end of the high and low speed rotating shaft 351 is clamped on the fourth shift fork 350. The high and low speed pull plate 352 is rotated clockwise / counterclockwise to control the fourth shift fork 350 to slide left and right. The auxiliary slave shift mechanism is provided with an external spline on the right side of the auxiliary speed gear set 242, and the auxiliary low speed gear 243 on its right side is provided with a left internal spline to cooperate with it. The auxiliary low-speed gear 243 is a 42T gear, and its gear hole is sleeved with an oil-free bearing 244 (for lubrication) and then installed on the rear axle output shaft 240, and fixed with a shaft retaining ring and a friction-reducing gasket to prevent it from sliding left and right, so the auxiliary low-speed gear 243 can run idly. The oil-free bearing 244 (containing graphite) is installed on the rear axle output shaft 240 through clearance fit, and the auxiliary low-speed gear 243 is installed on the oil-free bearing 244 through clearance fit. When the auxiliary low-speed gear 243 rotates, the rear axle output shaft 240 does not rotate, and the oil-free bearing 244 plays a lubricating role. The auxiliary speed change gear set 242 and the auxiliary low-speed gear 243 are splined left and right to achieve the third-stage auxiliary speed change.

[0057] like Figure 12-13As shown, the intermediate shaft 260 is installed in the gearbox body through the support of two bearings, and the input slave gear 261 is installed on the intermediate shaft 260 through spline matching and fixed by bearings to prevent it from sliding. The input slave gear 261 is a helical gear 28T. The left end of the intermediate shaft 260 is fixed on the left end cover 130 through a bearing, and the right end is fixed on the support plate 111 through a bearing. The fixing of the bearings at both ends makes the transmission of the intermediate shaft 260 more stable. The rear axle output shaft 240 is arranged on the right side of the intermediate shaft 260 coaxially, and the two form a fourth axis centerline space. The intermediate shaft 260 is transmission-fixedly connected to the main shift gear set, which is composed of a number of gears with different numbers of teeth, and each gear is fixed on the intermediate shaft 260. The number of gears is set according to the number of gear positions, and in this embodiment, the main shift gear set and the slave shift mechanism cooperate to realize the main shift. Therefore, the main shift gear set includes the following gears fixed in sequence on the intermediate shaft 260: 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.

[0058] The input master gear 212 meshes with the input slave gear 261, and the input slave gear 261 is mounted on the intermediate shaft 260 through a spline fit. Therefore, when the engine input shaft rotates, the intermediate shaft 260 also rotates at the same time. At this time, the first reverse gear set 251 (21T gear) meshed with the first intermediate gear 262 fixed on the intermediate shaft 260 also rotates synchronously. Since the first reverse gear set 251 is mounted on the front axle output shaft 250 through a needle bearing, the front axle output shaft 250 does not rotate.

[0059] At this time, 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.

[0060] In some embodiments, 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 basically according to the positions of the vertices of the quadrilateral. That is to say, the projections of the axis centerline of the power output shaft 230 and the axis centerlines of the axis where the first reversing gear set 251 is located, the speed change shaft 220, and the intermediate shaft 260 are arranged at the four corners of the quadrilateral, and the projections of any three axis centerlines are not on the same straight line. The projection is the projection of the axis centerline on the vertical plane, and the projection forms a point. The input main gear 212 on the first axis space 401 is meshed with the input slave gear 261 on the fourth axis space 404 to transmit power to the intermediate shaft 260. The first intermediate gear 262 on the fourth axis space 404 is meshed with the first reversing gear set 251 on the second axis space 402. The first reversing gear set 251 in the second axis space is meshed with the second reversing gear 231 in the third axis space 403.

[0061] When the engine is input, the four axis space parts of the shaft enter idle rotation. At this time, each shift gear is in the neutral position and does not mesh with other gears.

[0062] 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 meshed with the first intermediate gear 262, the second intermediate gear 263, the third intermediate gear 264 in the fourth axis space 404 and the first reversing gear set 251 in the second axis space 402, thereby realizing a 4-stage main speed change in the layout of the first, fourth and second axis spaces.

[0063] Auxiliary speed change: The auxiliary low-speed gear 243 and the auxiliary speed change gear set 242 of the fourth axis space are respectively meshed 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.

[0064] Power output speed change: the second reverse gear 231 of the third axis space 403 is meshed 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 meshed 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.

[0065] By setting the intermediate shaft 260, the speed change shaft 220 and the power output shaft 230 are provided with speed transmission, and one shaft has two speed change shafts output. The efficient setting of the intermediate shaft 260 makes the gearbox more compact. By setting the first reverse gear set 251 on the front axle output shaft 250, the speed change shaft 220 and the power output shaft 230 are provided with reverse gear respectively, and one reverse gear set is used for multiple purposes. The setting of the four axis spaces forms the transmission coordination between the gears of four plane dimensions, making the gearbox compact and small in space. Moreover, by cooperating with the shift operating lever, a clutchless multi-speed gearbox is realized, which simplifies the structure of the gearbox and greatly reduces the production and use costs.

[0066] 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 in the gearbox 100, and a shift control shaft 330 controlled by the outside of the gearbox 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.

[0067] The speed shift operating shaft 330 is mounted on the upper cover 120, the gear engaging shaft 331 is mounted on the speed shift operating shaft 330 and fixed by a fixing sleeve 332 and a return spring 333, and 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.

[0068] like Figure 4 The shift operating device 300 further includes a power output shaft 341, a power output pull plate 342 and a hollow pin 343. The power output shaft 341 and the power output pull 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. The power output pull plate 342 is rotated clockwise or counterclockwise to control the third shift fork 340 to slide left and right, and the third shift gear set 232 is driven to slide left and right on the power output shaft 230.

[0069] (1) Travel speed shifting instructions like Figure 5, as shown in 12-13 (left, right, front, and back are marked in the figure), the gear-engaging shaft 331 is fixed on the speed-shifting operating shaft 330. When the speed-shifting operating shaft 330 slides forward, the gear-engaging shaft falls into the groove of the first shift fork 310. At this time, the first shift fork 310 is in a neutral position. The speed-shifting operating shaft 330 is rotated clockwise and counterclockwise to manipulate the first shift fork 310 to control the first shift gear set 222; similarly, when the speed-shifting operating shaft 330 slides backward, the gear-engaging shaft falls into the groove of the second shift fork 320. At this time, the second shift fork 320 is in a neutral position. The speed-shifting operating shaft 330 is rotated clockwise and counterclockwise to manipulate the second shift fork 320 to control the second shift gear set 223.

[0070] 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.

[0071] The second shift fork 320 controls the second shift gear set 223 to slide leftward, so that its 28T tooth meshes with the 24T tooth on the first reverse gear set 251, which is the reverse gear. As described above, after the engine is running, the first reverse gear set 251 runs synchronously, and after the second shift gear set 223 meshes with it, the speed change shaft 220 starts to run.

[0072] The second shift fork 320 controls the second shift gear set 223 to slide rightward, so that its 24T teeth mesh with the first intermediate gear 262 (19T teeth) on the intermediate shaft 260, which is now the forward 2nd gear. The first shift fork 310 controls the first shift gear set 222 to slide leftward, so that its 31T teeth mesh with the second intermediate gear 263 (12T teeth) on the intermediate shaft 260, which is now the forward 1st gear. The first shift fork 310 controls the first shift gear set 222 to slide rightward, so that its 18T teeth mesh with the third intermediate gear 264 (25 teeth) on the intermediate shaft 260, which is now the forward 3rd gear. As described above, when the engine is running, the intermediate shaft 260 runs synchronously, and after the second shift gear set 223 or the first shift gear set 222 meshes with the gear on the intermediate shaft 260, the speed change shaft 220 starts to run. After the first shift fork 310 is used for operation, it needs to be returned to the neutral position before the second shift fork 320 can be operated, and vice versa.

[0073] (2) Instructions for shifting high, medium and low gears 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 leftward, so that it falls into the medium speed gear or the high speed gear.

[0074] The first synchronous gear 241 (gear 13T) and the auxiliary speed gear set 242 are mounted on the rear axle output shaft 240 through spline fitting, and the three rotate or stop synchronously. The auxiliary low-speed gear 243 is mounted on the rear axle output shaft through the clearance fitting of the oil-free bearing 244. When the auxiliary low-speed gear 243 rotates, the rear axle output shaft does not rotate.

[0075] The auxiliary speed gear set 242 is usually in the low speed gear position, that is, the external spline of the auxiliary speed gear set 242 is inserted into the internal spline of the auxiliary low speed gear 243. At this time, the auxiliary speed gear set 242 and the auxiliary low speed gear 243 rotate together through the spline cooperation, and the rear axle output shaft 240 rotates together with the auxiliary speed gear set 242. The auxiliary low speed gear 243 has 42T teeth and is always meshed with the first synchronous gear 241 on the speed shaft 220 with 13T teeth. After the speed shaft 220 is running, the rear axle output shaft 240 also runs synchronously. For example, the fourth shift fork 350 controls the auxiliary speed gear set 242 to slide to the left, so that its 20T teeth are meshed with the 23T teeth on the speed shaft 220, which is a medium speed gear; it continues to slide to the left so that its 14T teeth are meshed with the 29T teeth on the speed shaft 220, which is a high speed gear.

[0076] The second synchronous gear 252 (20T gear) is mounted on the front axle output shaft 250 through spline fitting, and the two rotate or stop synchronously. Since the second synchronous gear 252 (20T gear) is connected to the first synchronous gear 241 (13T gear) mounted on the rear axle output shaft 240, when the rear axle output shaft 240 rotates, the front axle output shaft 250 rotates synchronously.

[0077] At this time, the transmission speed can be combined with the main speed and the auxiliary speed to obtain 9 forward gears and 3 reverse gears. The main speed is forward 1st gear, forward 2nd gear, forward 3rd gear and reverse gear; the auxiliary speed is low speed gear, medium speed gear and high speed gear.

[0078] like Figure 13-14 As shown, the third shift gear set 232 is mounted on the power output shaft 230 through spline matching, and the two rotate or stop at the same time. The initial position of the third shift gear set 232 is the first neutral position, and its gears are not engaged with other gears. The third shift fork 340 controls the third shift gear set 232 to slide to the left, so that its internal spline is inserted into the external spline of the second reverse gear 231. At this time, the two gears rotate synchronously with the power output shaft, and the power output is in the reverse gear position. As mentioned above, after the engine is running, the second reverse gear 231 runs synchronously, and at this time the power output shaft 230 starts to reverse.

[0079] After the third shift fork 340 controls the third shift gear set 232 to slide rightward to the first neutral position, it slides rightward again to make its 24T teeth mesh with the first intermediate gear 262 (19T teeth) on the intermediate shaft 260, which is the forward 1st gear. The third shift fork 340 controls the third shift gear set 232 to continue to slide rightward to reach the second neutral position, and then continues to slide rightward to make its 18T teeth mesh with the third intermediate gear 264 (25T teeth) on the intermediate shaft 260, which is the forward 2nd gear. As described above, after the engine is running, the intermediate shaft 260 runs synchronously. When the third shift gear set 232 meshes with the intermediate shaft 260, the power output shaft outputs the forward 1st and 2nd gears respectively.

[0080] (4) Front power output shift instructions In another embodiment, a front power output shaft 270 is further provided, and the front power output shaft 270 outputs power to a front PTO position to drive an agricultural implement attached to the front side of the tractor.

[0081] like Figure 17-27 As shown, the third shift gear set 232 is mounted on the power output shaft 230 through spline matching, and can slide left and right onto the spline and the second reverse gear 231. The third shift fork 340 controls the third shift gear set 232 to slide rightward to reach the second neutral position, and then continues to slide rightward to make its 18T gear mesh with the third intermediate gear 264 (25T gear) of the intermediate shaft 260 (as mentioned above, it is the forward second gear of the power output shaft). At this time, the 18T gear meshes with the third intermediate gear 264 (25T gear) and gear 27T on the intermediate gear shaft at the same time. Since gear 27T meshes with the 17T gear on the front power output gear shaft, the front power output gear shaft also runs at the same time.

[0082] 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 in which the 18T tooth in the third shift gear set 232 is meshed with 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 clearance fit. Therefore, the power output shaft 230 does not rotate, and the 18T tooth gear is meshed with the 27T tooth gear, which ultimately drives the front power output shaft 270 to rotate and output power to the front PTO position.

[0083] Since the rear power output shaft is located at the bottom of the gearbox and is immersed in the gearbox oil, when the outer spline sleeve 271 and the second reverse gear 231 are clearance-matched with the power output shaft 230, standard lubricating parts such as needle bearings or oil-free bearings are not required. like Figure 22-26As shown, when the tractor starts to run, the third shift fork 340 of the power output is generally in the neutral position 1. At this time, the internal spline of the third shift gear set 232 does not contact the reverse gear 2, and the gears of the third shift gear set 232 do not mesh with other gears, so the power output shaft and the front power output shaft do not operate.

[0084] like Fig. 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 inserted into the external spline of the second reverse gear, and the other half of the internal spline is installed on the spline of the power output shaft. Since the second reverse gear has been running since the engine started, the power output shaft starts to reverse under the action of the spline matching. The forward and reverse rotation of the present invention is 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) reversed, transmitted to the reverse gear 1 (21 / 24T) forward, transmitted to the second reverse gear reversed, and the rear axle output shaft running with the second reverse gear also reversed.

[0085] like Figure 23-24 As shown, push back to the neutral position 1, and then push the shift fork back to the forward position of the rear PTO. At this time, the 24T tooth in the shift gear 18 / 24T meshes with the 19T tooth on the intermediate gear shaft. After the engine is started, the intermediate gear shaft continues to operate, and the shift gear 18 / 24T meshing with its 19T tooth begins to operate. Since the shift gear 18 / 24T is mounted on the power output shaft through spline matching at this time, 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 gear) rotates forward, the power is transmitted to the helical gear 28 and the intermediate gear shaft (19T) in reverse, and is transmitted to the shift gear 18 / 24T in forward rotation, and the rear axle output shaft that operates with the shift gear 18 / 24T also rotates forward.

[0086] like Fig.25 As shown, the shift fork is moved backward to the neutral position 2. At this time, the internal spline of the shift gear 18 / 24T does not contact the reverse gear 2, and its 18 / 24T teeth do not mesh with other gears, so the rear power output shaft does not rotate.

[0087] like Fig.26As shown, move the shift fork backward to the front PTO position. At this time, the 18T tooth in the shift gear 18 / 24T is meshed with the 25T tooth and gear 27T on the intermediate gear shaft at the same time. After the engine is started, the intermediate gear shaft continues to operate, driving the shift gear 18 / 24T meshed with its 25T tooth to operate, and the shift gear 18 / 24T in turn drives the gear 27T to operate. Since the gear 27T is meshed with the 17T tooth on the front power output gear shaft, the front power output gear shaft also operates at the same time. At this time, since the inner spline of the shift gear 18 / 24T is completely located on the outer spline sleeve, and the outer spline sleeve and the rear power output shaft are clearance fit, the rear power output shaft does not operate.

[0088] 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.

[0089] like Fig. 27 As shown, if the front power output needs to be reversed (relative to the power input gear shaft), adding a third reverse gear set 274 can solve the problem. The third reverse gear set 274 includes a pair of 12 / 16T tooth linkage gears (gear shaft 12 / 16T) set on the gear shaft. The operation up to gear 27T is the same as the forward rotation of the front PTO output, and then gear 27T meshes with the 16T teeth of gear shaft 12 / 16T, and gear shaft 12 / 16T operates. At the same time, the 12T teeth of gear shaft 12 / 16T mesh with gear 21T, and gear 21T operates. Since the gear 21T teeth and the front power output shaft are assembled through splines, the front power output shaft operates at the same time.

[0090] 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, transmitted to the gear 21T and the front power output shaft in reverse rotation.

[0091] 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, spline shafts, etc., to provide a power source for the agricultural machinery. like Figure 14-16 As shown, the shift fork includes 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 installed and fixed on the fork shafts with clearance fit, and the corresponding ones are the first fork shaft 311, the second fork shaft 321, the third fork shaft 344 and the fourth fork shaft 353.

[0092] Taking the first shift fork 310 and the second shift fork 320 as examples, 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.

[0093] The first shift fork 310 is provided with a sleeve 312, and the sleeve 312 is installed on the first shift fork shaft 311 through clearance fit, so that the first shift fork shaft 311 can slide in the sleeve 312. The first shift fork shaft 311 is provided with a shift slot 313, and the first shift fork shaft 311 is provided with three shift slots 313. The steel ball 314 falls into the shift slot 313 of the first shift fork shaft 311 through the elastic force of the compression spring 315. Due to the elastic force of the spring, only a large torque can push the first shift fork 310 to drive the steel ball to fall into another shift slot to complete the shifting work.

[0094] The second shift fork 320 has a substantially similar shifting structure to the first shift fork 310, and respectively shifts the first shift gear set 222 and the second shift gear set 223 provided on the speed change shaft 220. The first shift fork shaft 311 and the second shift fork shaft 321 are provided in parallel with each other, and a space is provided between them, and a gear engaging shaft 331 is inserted into the space. The second shift fork 320 and the first shift fork 310 are provided with a shifting groove relative to each other, and one end of the gear engaging shaft 331 is inserted into the shifting groove. The gear engaging shaft 331 can control the first shift fork 310 and the second shift fork 320 respectively. Specifically, the speed change operating shaft 330 can move laterally and can rotate. When the speed shift operating shaft 330 moves laterally, the gear engaging 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 engaging shaft 331, which shifts the second shift fork 320 or the first shift fork 310 to shift gears, thereby realizing the mobile shifting of multiple shift forks with one shaft.

[0095] In order to ensure the stability of gear shifting, a baffle 334 is provided at the edge of the moving range of the gear-engaging shaft 331. The baffle 334 is fixed on the gearbox body 110 or the upper cover 120, and a through hole is opened in the middle. The gear-engaging shaft 331 moves in the through hole and is restricted by the edge of the through hole.

[0096] In addition, the third shift fork 340 is taken 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 the compression spring 315 are installed in the third shift fork 340 and cooperate with the grooves provided on the third shift fork shaft 344 to limit the third shift fork 340. Specifically, the third shift fork shaft 344 is provided with a backward 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 sequence.

[0097] The third shift fork 340 is stuck on the third shift gear set 232 to control it to slide on the power output shaft 230, realizing the reverse gear, the first neutral, the first forward gear, the second neutral, and the second forward gear. Therefore, there are 5 grooves on the third shift fork shaft 344 that slide left and right to represent the 5 gears. The steel ball falls into the five grooves of the third shift fork shaft 344, the first neutral groove 3442, the first forward groove 3443, the second neutral groove 3444, and the second forward groove 3445 through the elastic force of the compression spring, realizing the physical control of the reverse gear, the first neutral, the first forward gear, the second neutral, and the second forward gear of the power output shaft 230. 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 to complete the shifting work. The specific action is that by twisting the power output pull plate 342, the power output pull plate 342 swings around the hollow pin 343 and drives the hollow pin 343 to rotate, and then transmits 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-shift fork 340, and the three-shift fork 340 moves on the five gears of the third fork shaft 344, realizing the regulation 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 arranged on the speed change shaft (220) in sequence; The intermediate shaft (260) comprises an input slave gear (261) meshing with an input main gear (212) and a main shift gear set fixed thereon, 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 arranged on the coaxial center line of the intermediate shaft (260), and 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; It comprises a first reverse gear set (251), the first reverse gear set (251) comprising a synchronously rotating gear 1 and a gear 2, the gear 1 being meshed with the main shift gear set, the slave shift mechanism sliding to mesh with the gear 2, thereby realizing reverse gear shift of the main speed change; The power output shaft (230) is provided with a third shifting gear set (232) and a second reverse gear (231); the second reverse gear (231) is idly mounted on the power output shaft (230) and meshes with the second gear of the first reverse gear set (251) and rotates idly; the third shifting gear set (232) slides on the power output shaft (230) and meshes with the main shifting gear set and is transmission-connected with the second reverse gear (231) in sequence, thereby achieving shifting of power output from the power output shaft (230); It comprises a front power output shaft (270), the front power output shaft (270) comprising a front power gear (273), the front power gear (273) being 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 both forward and backward according to claim 1, characterized in that: A positioning shaft (271) is provided on the lower side of the housing (110), and a positioning gear (272) is provided on the positioning shaft (271). The positioning gear (272) is meshed with a transmission position of the third shift gear set (232) for transmission, and the positioning gear (272) is meshed with the front power gear (273) for transmission.

3. A gearbox capable of outputting power both forward and backward according to claim 2, characterized in that: The positioning shaft (271) is installed in the gearbox body through clearance fit, one end of which is positioned by the shaft hole of the gearbox body, and the other end of which is positioned by the end surface of the gearbox front cover.

4. A gearbox capable of outputting power both forward and backward according to claim 2, characterized in that: The inner hole of the positioning shaft gear (272) is equipped with a bearing through a clearance fit, and the inner hole of the bearing is installed on the positioning shaft (270).

5. A gearbox capable of outputting power both forward and backward 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 respectively connected with the external spline, the external spline sleeve, and the gear external spline in sequence; at the position where the third shift gear set (232) is connected with the external spline sleeve, the third shift gear set (232) is meshed with the main shift gear set and the positioning 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) and the speed change shaft (220) and the intermediate shaft (260) are on different axis lines, the first reversing gear set (251) is idly mounted on the front axle output shaft (250) and can rotate idly, the front axle output shaft (250) is fixed with a second synchronous gear (252), the rear axle output shaft (240) is transmission-connected with a first synchronous gear (241), and the first synchronous gear (241) and the second synchronous gear (252) are meshed and transmission-driven, 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 shifting mechanism comprises an auxiliary speed gear set (242) and an auxiliary low-speed gear (243); the auxiliary low-speed gear (243) is loosely sleeved on the rear axle output shaft (240) and is provided with an internal spline; 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 shifting gear set comprises a high-speed gear (224), a medium-speed gear (226) and a low-speed gear (225) which are fixedly connected to the speed shaft (220) and are arranged in sequence to the left; the low-speed gear (225) is meshed with the auxiliary low-speed gear (243); the auxiliary speed gear set (242) is slidably meshed 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 coordinated transmission, thereby realizing high, medium and low speed conversion.

8. A gearbox capable of outputting power both forward and backward 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) leftward and rightward can mesh with the second intermediate gear (263) and the third intermediate gear (264) to achieve first and third gear shifting; sliding the second shift gear set (223) can mesh with the first intermediate gear (262) to achieve second gear shifting; sliding the second shift gear set (223) can mesh with gear 2 of the first reverse gear set (251) to achieve reverse gear shifting; the first shift gear set (222) and the second shift gear set (223) are respectively provided with a neutral position.

9. A gearbox capable of outputting power both forward and backward 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. A gearbox capable of outputting power both forward and backward 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) drives the first shift gear set (222) to slide, the second shift fork (320) drives the second shift gear set (223) to slide, the third shift fork (340) drives the third shift gear set (232) to slide, and the fourth shift fork (350) drives the auxiliary speed gear set (242) to slide.

11. A gearbox capable of outputting power both forward and backward according to claim 6, characterized in that: The housing (110) further comprises a left end cover (130) and a support plate (111); the input shaft (210), the intermediate shaft (260), the front axle output shaft (250), and one end of the power output shaft (230) are fixed to the left end cover (130) via bearings; the intermediate shaft (260), the front axle output shaft (250), the other end of 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. A gearbox capable of outputting power both forward and backward 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 a gearbox capable of outputting power to the front and rear as claimed in 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 drivingly connected to the front power output shaft (270) and the power output shaft (230).

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