3n+3n step-variable transmission system

Abstract

The application provides a 3N+3N gear shift transmission system, which comprises an input shaft, a first intermediate shaft, a second intermediate shaft and an output shaft, the input shaft and the first intermediate shaft are transmissionally connected through a forward-reverse gear shift mechanism, the first intermediate shaft and the second intermediate shaft are transmissionally connected through a multi-gear shift mechanism, the second intermediate shaft and the output shaft are transmissionally connected through a high-low speed gear shift mechanism, the second intermediate shaft is provided with a fixed intermediate driving wheel and a rotatable crawl gear driving wheel, the output shaft is rotationally connected with an intermediate driven wheel and a crawl gear driven wheel, the intermediate driving wheel, the intermediate driven wheel, the crawl gear driving wheel and the crawl gear driven wheel are transmissionally connected in sequence, and one side of the crawl gear driven wheel is provided with a crawl gear shifter. By arranging the intermediate shaft between the input shaft and the output shaft, the gear position effect of the multi-gear shift mechanism is doubled, the 3N+3N gear shift is realized, the number of changeable gear positions is greatly increased, and the speed change requirement of multiple gear positions is met.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of tractor transmission system, in particular to a 3N+3N gear transmission system. BACKGROUND

[0002] At present, the operation conditions of tractors require more and more variable speeds. The existing transmission technology generally adopts a two-axle transmission structure, and the two axles are connected by gear transmission. The gear transmission realizes the gear shifting by engaging different gears through the meshing device. This method occupies a large space in the length direction of the tractor. In the limited length space of the tractor, the number of changeable gears is too small to meet the demand of multiple gears. When the number of changeable gears is large, the wheelbase needs to be lengthened, which means that the turning radius of the whole machine increases, the steering performance decreases, the number of parts increases, and the assembly and management are not convenient, thereby reducing the versatility of the tractor and increasing the manufacturing cost. SUMMARY

[0003] The technical problem to be solved by the present application is how to increase the number of changeable gears in the limited length space of the tractor to meet the demand of multiple gear shifting.

[0004] The technical solution of the present application to solve the above technical problem is as follows:

[0005] The present application provides a 3N+3N gear transmission system, which comprises an input shaft, a first intermediate shaft, a second intermediate shaft and an output shaft. The input shaft and the first intermediate shaft are connected by a forward and reverse gear shifting mechanism. The first intermediate shaft and the second intermediate shaft are connected by a multi-gear shifting mechanism. The second intermediate shaft and the output shaft are connected by a high and low speed gear shifting mechanism.

[0006] The second intermediate shaft is connected with an intermediate driving wheel, and the second intermediate shaft is rotatably connected with a crawling gear driving wheel. The output shaft is rotatably connected with an intermediate driven wheel and a crawling gear driven wheel. The outer periphery of the intermediate driven wheel is connected with the intermediate driving wheel, the hub part of the intermediate driven wheel is connected with the outer periphery of the crawling gear driving wheel, and the hub part of the crawling gear driving wheel is connected with the crawling gear driven wheel. One side of the crawling gear driven wheel is provided with a crawling gear meshing device, and the crawling gear meshing device is connected with the output shaft.

[0007] The hub part of the intermediate driven wheel and the hub part of the crawling gear driving wheel are both provided with external teeth.

[0008] The present application has the following advantages:

[0009] The application is characterized in that: the intermediate shaft is arranged between the input shaft and the output shaft, the forward gear and the reverse gear are switched between the input shaft and the first intermediate shaft, and the high-speed gear and the low-speed gear are switched between the second intermediate shaft and the output shaft, so that the gear effect of the multi-gear shifting mechanism is doubled, 3N+3N gear shifting is realized (N is the number of gears of the multi-gear shifting mechanism), the number of gears that can be switched is greatly increased in the limited length of the tractor, and the speed change requirement of the multi-gear is met. The steering performance and versatility of the tractor are improved, and the manufacturing cost is reduced.

[0010] Based on the above technical scheme, the application can be further improved as follows.

[0011] Further, the high-low gear shifting mechanism comprises a low-speed gear driving wheel and a high-speed gear driving wheel which are both in transmission connection with the second intermediate shaft, and a low-speed gear driven wheel and a high-speed gear driven wheel which are both rotatably sleeved on the output shaft, the low-speed gear driven wheel is in transmission connection with the low-speed gear driving wheel, and the high-speed gear driven wheel is in transmission connection with the high-speed gear driving wheel; a high-low gear synchronizer is arranged between the low-speed gear driven wheel and the high-speed gear driven wheel, and the high-low gear synchronizer is in transmission connection with the output shaft.

[0012] The high-speed gear and the low-speed gear are switched, the gear effect of the multi-gear shifting mechanism is doubled, 3N+3N gear shifting is realized, and the multi-gear shifting requirement of the tractor is met.

[0013] Further, the low-speed gear driving wheel, the high-speed gear driving wheel, the low-speed gear driven wheel and the high-speed gear driven wheel are all gears, the low-speed gear driving wheel and the intermediate driving wheel are the same gear, and the low-speed gear driven wheel and the intermediate driven wheel are the same gear.

[0014] The gear transmission is stable, and the transmission is reliable; meanwhile, the low-speed gear driving wheel and the driven wheel are used as the intermediate driving wheel and the driven wheel, the number of gears is reduced, the structure is compact, maintenance is facilitated, and the cost is reduced.

[0015] Further, the forward-reverse gear shifting mechanism comprises a reverse gear driving wheel, a forward gear driving wheel, a reverse gear driven wheel and a forward gear driven wheel, the reverse gear driving wheel is in transmission connection with the reverse gear driven wheel through a idler wheel, and the forward gear driving wheel is in transmission connection with the forward gear driven wheel.

[0016] The reverse gear driving wheel and the forward gear driving wheel are both in transmission connection with the input shaft, the reverse gear driven wheel and the forward gear driven wheel are both rotatably sleeved on the first intermediate shaft, a forward-reverse gear synchronizer is arranged between the reverse gear driven wheel and the forward gear driven wheel, and the forward-reverse gear synchronizer is in transmission connection with the first intermediate shaft.

[0017] The shifting operation is convenient through the synchronizer; the transmission direction of the idle gear is changed from the reverse driving gear to the reverse driven gear, the rotating direction of the first intermediate shaft is opposite in the reverse gear compared with that in the forward gear, so that the gear shifting is realized in the reverse gear and the forward gear, and the versatility is good, and the tractor can be used bidirectionally in some working conditions.

[0018] Further, the reverse driving gear, the forward driving gear, the reverse driven gear, the forward driven gear and the idle gear are all gears, one side of the teeth of the idle gear is engaged with the reverse driving gear, and the other side of the teeth of the idle gear is engaged with the reverse driven gear.

[0019] The occupied space is small, the transmission ratio is stable, the reliability is good, and the installation is convenient.

[0020] Further, the shaft center of the reverse driving gear, the shaft center of the reverse driven gear and the shaft center of the idle gear are parallel to each other and not in the same plane.

[0021] The occupied space is small, and the distance between the input shaft and the first intermediate shaft is reduced, so that the difference between the driving gear and the driven gear of the reverse gear and the forward gear can be reduced, the speed difference between the reverse gear and the forward gear is small, and the operation comfort is good.

[0022] Further, the reverse driving gear and the forward driving gear are both coupled with the input shaft through the spline structure.

[0023] The disassembly and assembly are convenient, the spline structure is uniformly stressed, the transmission is reliable, the stability is good, and the service life is long.

[0024] Further, the multi-gear shifting mechanism comprises a first gear driving gear, a second gear driving gear, a third gear driving gear and a fourth gear driving gear which are all coupled with the first intermediate shaft, and a first gear driven gear, a second gear driven gear, a third gear driven gear and a fourth gear driven gear which are all rotatably sleeved on the second intermediate shaft, the first gear driven gear is coupled with the first gear driving gear, the second gear driven gear is coupled with the second gear driving gear, the third gear driven gear is coupled with the third gear driving gear, and the fourth gear driven gear is coupled with the fourth gear driving gear.

[0025] A first-second gear synchronizer is arranged between the first gear driven gear and the second gear driven gear, and a third-fourth gear synchronizer is arranged between the third gear driven gear and the fourth gear driven gear, and the first-second gear synchronizer and the third-fourth gear synchronizer are both coupled with the second intermediate shaft.

[0026] The 12-gear shifting of high-speed first to fourth gears, low-speed first to fourth gears and crawling first to fourth gears is realized, the multi-gear shifting demand of the tractor is met, and the shifting operation is convenient.

[0027] Further, the first gear driving gear, the second gear driving gear, the third gear driving gear, the fourth gear driving gear, the first gear driven gear, the second gear driven gear, the third gear driven gear and the fourth gear driven gear are all gears.

[0028] Small, transmission ratio stability, good reliability, and easy to install.

[0029] Further, the first intermediate shaft is fixed with the first and second driving wheels, the third and fourth driving wheels are connected with the first intermediate shaft through a spline structure.

[0030] Since the first and second driving wheels have small diameters, they are fixed on the first intermediate shaft and can be integrally machined, which is convenient and has high strength; the spline structure of the third and fourth driving wheels facilitates disassembly and uniform stress; and the service life is long. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 The structure of the application is shown in the figure.

[0032] In the drawings, the technical features represented by the reference signs are as follows:

[0033] 1 - input shaft; 11 - reverse driving wheel; 12 - forward driving wheel;

[0034] 2 - first intermediate shaft; 21 - reverse driven wheel; 22 - forward driven wheel; 23 - forward and reverse synchronizer; 24 - first driving wheel; 25 - second driving wheel; 26 - third driving wheel; 27 - fourth driving wheel;

[0035] 3 - second intermediate shaft; 31 - first driven wheel; 32 - second driven wheel; 33 - third driven wheel; 34 - fourth driven wheel; 35 - first and second synchronizer; 36 - third and fourth synchronizer; 37 - low-speed driving wheel; 38 - high-speed driving wheel; 39 - crawl driving wheel; 4 - output shaft; 41 - low-speed driven wheel; 42 - high-speed driven wheel; 43 - high and low speed synchronizer; 44 - crawl driven wheel; 45 - crawl gear;

[0036] 5 - idler. DETAILED DESCRIPTION

[0037] The principles and features of the application are described below, and the examples are used to explain the application and not to limit the scope of the application.

[0038] The application is described in Figure 1 .

[0039] The application provides a 3N+3N gear transmission system, which comprises an input shaft 1, a first intermediate shaft 2, a second intermediate shaft 3, and an output shaft 4, wherein the input shaft 1 and the first intermediate shaft 2 are connected through a forward and reverse gear shifting mechanism; the first intermediate shaft 2 and the second intermediate shaft 3 are connected through a multi-gear shifting mechanism; and the second intermediate shaft 3 and the output shaft 4 are connected through a high and low speed gear shifting mechanism.

[0040] The second intermediate shaft 3 is connected with an intermediate driving wheel, the second intermediate shaft 3 is connected with a crawling gear driving wheel 39, the output shaft 4 is connected with an intermediate driven wheel and a crawling gear driven wheel 44; the outer periphery of the intermediate driven wheel is connected with the intermediate driving wheel, the hub of the intermediate driven wheel is connected with the outer periphery of the crawling gear driving wheel 39, the hub of the crawling gear driving wheel 39 is connected with the crawling gear driven wheel 44; one side of the crawling gear driven wheel 44 is provided with a crawling gear clutch 45, the crawling gear clutch 45 is connected with the output shaft 4.

[0041] The hub of the intermediate driven wheel and the hub of the crawling gear driving wheel 39 are both provided with external teeth.

[0042] Principle:

[0043] The forward-reverse gear shifting mechanism is used for transmission between the input shaft 1 and the first intermediate shaft 2, and controls the transmission direction to switch the forward gear and the reverse gear, wherein the rotation direction of the first intermediate shaft 2 is opposite in the reverse gear compared with the forward gear, and the forward-reverse gear shifting mechanism in the prior art can be used. The multi-gear shifting mechanism is used for transmission between the first intermediate shaft 2 and the second intermediate shaft 3, and controls the transmission ratio to switch the gear, and the shifting mechanism and the transmission structure in the prior art can be used. The high-low speed gear shifting mechanism is used for transmission between the second intermediate shaft 3 and the output shaft 4, and controls the transmission ratio to switch the high speed gear and the low speed gear, and the shifting mechanism and the transmission structure in the prior art can be used.

[0044] 3N+3N gear transmission system, N is the number of gears of the multi-gear shifting mechanism. When the high-low speed gear shifting mechanism is in the high speed gear, the gears corresponding to the multi-gear shifting mechanism are high speed gears, which are suitable for high speed driving; when the high-low speed gear shifting mechanism is in the low speed gear, the gears corresponding to the multi-gear shifting mechanism are low speed gears, which are suitable for load operation; at the same time, when the high-low speed gear shifting mechanism is in the neutral gear, the crawling gear clutch 45 can be moved to engage with the crawling gear driven wheel 44, the power on the second intermediate shaft 3 is transmitted through the intermediate driving wheel→the intermediate driven wheel→the crawling gear driving wheel 39→the crawling gear driven wheel 44→the crawling gear clutch 45→the output shaft 4, thereby further reducing the speed, and the gears corresponding to the multi-gear shifting mechanism are crawling gears, which are suitable for greater load or extreme working conditions; in summary, 3N gear shifting (N is the number of gears of the multi-gear shifting mechanism) of high speed gears, low speed gears and crawling gears is realized; at the same time, the forward gear and the reverse gear both correspond to the aforementioned 3N gear shifting, so 3N+3N gear shifting can be performed. When the number of gears of the multi-gear shifting mechanism is 4, 12+12 gear shifting can be performed.

[0045] Note: The crawling block gear 45 can also use a synchronizer, in addition, a meshing gear sleeve can be sleeved on a fixed gear hoop fixed on the output shaft 4, and the meshing gear sleeve can be engaged or disengaged with the hub part of the crawling block driven wheel 44 by sliding along the axial direction.

[0046] Note: The above hub parts are all provided with external teeth by default, which can be used for meshing transmission with the meshing gear sleeve or the synchronizer.

[0047] In summary, by adopting the present application, the intermediate shaft is arranged between the input shaft 1 and the output shaft 4, the forward gear and the reverse gear are changed between the input shaft 1 and the first intermediate shaft 2, and the high-speed gear and the low-speed gear are changed between the second intermediate shaft 3 and the output shaft 4, so that the gear position effect of the multi-gear shifting mechanism is doubled, and 3N+3N gear shifting (N is the number of gear positions of the multi-gear shifting mechanism) is realized; in the limited tractor length space, the number of changeable gear positions is greatly increased, and the speed change requirement of multiple gear positions is met. The steering performance and versatility of the tractor are improved, and the manufacturing cost is reduced.

[0048] Further, the high-low gear shifting mechanism includes a low-speed gear driving wheel 37 and a high-speed gear driving wheel 38 both in transmission connection with the second intermediate shaft 3, and a low-speed gear driven wheel 41 and a high-speed gear driven wheel 42 both rotatably sleeved on the output shaft 4, the low-speed gear driven wheel 41 is in transmission connection with the low-speed gear driving wheel 37, and the high-speed gear driven wheel 42 is in transmission connection with the high-speed gear driving wheel 38; a high-low gear synchronizer 43 is arranged between the low-speed gear driven wheel 41 and the high-speed gear driven wheel 42, and the high-low gear synchronizer 43 is in transmission connection with the output shaft 4.

[0049] High-speed gear: the high-low gear synchronizer 43 is engaged with the high-speed gear driven wheel 42, and the power on the second intermediate shaft 3 is transmitted through the high-speed gear driving wheel 38→the high-speed gear driven wheel 42→the high-low gear synchronizer 43→the output shaft 4.

[0050] Low-speed gear: the high-low gear synchronizer 43 is engaged with the low-speed gear driven wheel 41, and the power on the second intermediate shaft 3 is transmitted through the low-speed gear driving wheel 37→the low-speed gear driven wheel 41→the high-low gear synchronizer 43→the output shaft 4.

[0051] Note: In addition to the above examples, the high-low gear synchronizer 43 can be arranged on the second intermediate shaft 3, and correspondingly, the low-speed gear driving wheel 37 and the high-speed gear driving wheel 38 are rotatably sleeved on the second intermediate shaft 3, and the low-speed gear driven wheel 41 and the high-speed gear driven wheel 42 are both in transmission connection with the output shaft 4; correspondingly, the intermediate driving wheel and the low-speed gear driving wheel 37 use two independent gears, and the intermediate driven wheel and the low-speed gear driven wheel 41 use two independent gears.

[0052] The high-speed gear and the low-speed gear are changed, the gear effect of the multi-gear shifting mechanism is doubled, the 3N+3N gear change is realized, and the multi-gear shifting requirement of the tractor is met.

[0053] Further, the low-speed gear driving wheel 37, the high-speed gear driving wheel 38, the low-speed gear driven wheel 41 and the high-speed gear driven wheel 42 are all gears, and the low-speed gear driving wheel 37 and the intermediate driving wheel are the same gear, and the low-speed gear driven wheel 41 and the intermediate driven wheel are the same gear.

[0054] The gear transmission ratio is stable and reliable, and the low-speed gear driving wheel and the driven wheel serve as the intermediate driving wheel and the driven wheel, thereby reducing the number of gears, compacting the structure, facilitating maintenance and reducing the cost.

[0055] Further, the forward-reverse gear shifting mechanism comprises a reverse gear driving wheel 11, a forward gear driving wheel 12, a reverse gear driven wheel 21 and a forward gear driven wheel 22, the reverse gear driving wheel 11 is in transmission connection with the reverse gear driven wheel 21 through the idler wheel 5, and the forward gear driving wheel 12 is in transmission connection with the forward gear driven wheel 22.

[0056] The reverse gear driving wheel 11 and the forward gear driving wheel 12 are in transmission connection with the input shaft 1, the reverse gear driven wheel 21 and the forward gear driven wheel 22 are rotatably sleeved on the first intermediate shaft 2, and the reverse gear driven wheel 21 and the forward gear driven wheel 22 are provided with a forward-reverse gear synchronizer 23, which is in transmission connection with the first intermediate shaft 2.

[0057] Note: the reverse gear driving wheel 11 is in transmission connection with the reverse gear driven wheel 21 through the idler wheel 5, Figure 1 In the middle, the gear area of the reverse gear driving wheel 11 and the reverse gear driven wheel 21 is only close in distance, and is not combined together.

[0058] Note: the synchronizer is a prior art, which can be engaged with one of the two side empty gear wheels in the axial direction, so as to drive the empty gear wheel and the shaft. In addition, it can also be replaced by a meshing gear sleeve to realize gear shifting. Figure 1 In the middle, in order to express in a two-dimensional drawing, the idler wheel 5 and the independent shaft on which it is located are rotated to show, and the actual position is (for example, a gear): one side of the outer periphery of the idler wheel 5 is engaged with the reverse gear driving wheel 11, and the other side is engaged with the reverse gear driven wheel 21.

[0059] Note: in addition to the above examples, the forward-reverse gear synchronizer 23 can also be arranged on the input shaft 1, and correspondingly, the reverse gear driving wheel 11 and the forward gear driving wheel 12 are rotatably sleeved on the input shaft 1, and the reverse gear driven wheel 21 and the forward gear driven wheel 22 are in transmission connection with the first intermediate shaft 2, which can also realize the change of the forward-reverse gear.

[0060] The shifting operation is convenient through the synchronizer; the transmission direction of the reverse drive wheel 11 to the reverse driven wheel 21 is changed through the idler wheel 5, the rotating direction of the first intermediate shaft 2 is opposite in the reverse gear to that in the forward gear, so that the gear position is changed in the reverse gear and the forward gear, and the versatility is good, and the tractor can be used bidirectionally in some working conditions.

[0061] Further, the reverse drive wheel 11, the forward drive wheel 12, the reverse driven wheel 21, the forward driven wheel 22 and the idler wheel 5 are all gears, one side of the teeth of the idler wheel 5 is engaged with the reverse drive wheel 11, and the other side of the teeth is engaged with the reverse driven wheel 21.

[0062] The occupied space is small, the transmission ratio is stable, the reliability is good, and the installation is convenient.

[0063] Further, the shaft center of the reverse drive wheel 11, the shaft center of the reverse driven wheel 21 and the shaft center of the idler wheel 5 are parallel to each other and not in the same plane.

[0064] The occupied space is small, and the distance between the input shaft 1 and the first intermediate shaft 2 is reduced, so that the difference between the drive wheel and the driven wheel of the reverse gear and the forward gear can be reduced, the speed difference between the reverse gear and the forward gear is small, and the operation comfort is good.

[0065] Further, the reverse drive wheel 11 and the forward drive wheel 12 are both coupled with the input shaft 1 through the spline structure.

[0066] The spline structure is convenient to disassemble and assemble, the force is uniform, the transmission is reliable, the stability is good, and the service life is long.

[0067] Further, the multi-gear shifting mechanism comprises a first gear drive wheel 24, a second gear drive wheel 25, a third gear drive wheel 26 and a fourth gear drive wheel 27 which are all coupled with the first intermediate shaft 2, and a first gear driven wheel 31, a second gear driven wheel 32, a third gear driven wheel 33 and a fourth gear driven wheel 34 which are all rotatably sleeved on the second intermediate shaft 3, the first gear driven wheel 31 is coupled with the first gear drive wheel 24, the second gear driven wheel 32 is coupled with the second gear drive wheel 25, the third gear driven wheel 33 is coupled with the third gear drive wheel 26, and the fourth gear driven wheel 34 is coupled with the fourth gear drive wheel 27.

[0068] A second gear synchronizer 35 is arranged between the first gear driven wheel 31 and the second gear driven wheel 32, and a third gear synchronizer 36 is arranged between the third gear driven wheel 33 and the fourth gear driven wheel 34, and the second gear synchronizer 35 and the third gear synchronizer 36 are both coupled with the second intermediate shaft 3.

[0069] The synchronizer is preferably in driving connection with the shaft and can be in driving connection with the shaft through a spline structure. The first-second gear synchronizer 35 and the third-fourth gear synchronizer 36 are both in driving connection with the second intermediate shaft 3 through a spline structure. In addition, in addition to the above examples, at least one of the first-second gear synchronizer 35 and the third-fourth gear synchronizer 36 can be arranged on the first intermediate shaft 2, and the driving wheels on both sides thereof are rotatably sleeved on the shaft on which they are arranged.

[0070] The first gear: the third-fourth gear synchronizer 36 is empty, and the first-second gear synchronizer 35 is in engagement with the first gear driven wheel 31; the second gear: the third-fourth gear synchronizer 36 is empty, and the first-second gear synchronizer 35 is in engagement with the second gear driven wheel 32; the third gear: the first-second gear synchronizer 35 is empty, and the third-fourth gear synchronizer 36 is in engagement with the third gear driven wheel 33; the fourth gear: the first-second gear synchronizer 35 is empty, and the third-fourth gear synchronizer 36 is in engagement with the fourth gear driven wheel 34. In combination with the high-speed gear, the low-speed gear and the crawl gear of the high-low gear shifting mechanism and the crawl gear of the crawl gear synchronizer 45, 12-gear shifting of the high-speed first to fourth gear, the low-speed first to fourth gear and the crawl first to fourth gear is formed. In combination with the forward gear and the reverse gear, 12+12-gear shifting is formed. (That is, the aforementioned 3N+3N, N=4).

[0071] In summary, 12-gear shifting of the high-speed first to fourth gear, the low-speed first to fourth gear and the crawl first to fourth gear is realized. The multi-gear shifting requirement of the tractor is met, and the gear shifting operation is convenient.

[0072] Further, the first gear driving wheel 24, the second gear driving wheel 25, the third gear driving wheel 26, the fourth gear driving wheel 27, the first gear driven wheel 31, the second gear driven wheel 32, the third gear driven wheel 33 and the fourth gear driven wheel 34 are all gears.

[0073] The device occupies a small space, has stable transmission ratio, good reliability and is convenient to install.

[0074] Further, the first gear driving wheel 24 and the second gear driving wheel 25 are fixed on the first intermediate shaft 2, and the third gear driving wheel 26 and the fourth gear driving wheel 27 are in driving connection with the first intermediate shaft 2 through a spline structure.

[0075] Since the first gear driving wheel 24 and the second gear driving wheel 25 have a small diameter, they can be integrally machined by being fixed on the first intermediate shaft 2, which is convenient for machining and has high strength; the spline structure of the third gear driving wheel 26 and the fourth gear driving wheel 27 makes them convenient to disassemble and assemble and uniformly stressed, thereby having a long service life.

[0076] In the description of the present application, it needs to be understood that if the description of the orientation, direction or positional relationship appears, for example, "center", "lengthwise", "transverse", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like, the orientation or positional relationship indicated in the specification is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of understanding the present application and simplifying the description, and does not indicate or imply that the indicated part, element or whole must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.

[0077] In addition, if the order description language appears, for example, "first", "second" and the like, the use in the specification is for the convenience of understanding or simplifying the description, for example, in order to distinguish a plurality of technical features of the same type or function, and it is necessary to mention separately, the specification may use the order description language of prefix or suffix to distinguish them. Therefore, it cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, the features with "first", "second" can be explicitly or implicitly included at least one feature. In the description of the present application, the meaning of "a plurality of" is at least two, for example, two, three, etc., unless otherwise specifically limited.

[0078] In the present application, if the structural relative action description language is used, for example, "mounting", "connecting", "connecting", "fixing" and the like, unless otherwise specified and limited, it should be understood in a broad sense. For example, "mounting", "connecting", "connecting" and the like can be fixedly connected, or can be detachably connected, or can be integrated; can be mechanically connected, or can be electrically connected; can be directly connected, or can be indirectly connected through an intermediate medium; can be the internal communication of two elements or the interaction relationship between two elements; "fixed" can be integrated fixed, or can be detachable fixed through a fastener; can be directly fixed, or can be fixed through an intermediate medium. For those skilled in the art, the specific meaning of the above description language in the present application can be understood according to the specific circumstances, the context, the text meaning of the preceding and following texts, etc.

[0079] In the present application, if there is a description of a term containing an accessory or connection meaning, for example, the first feature is "on" or "under" the second feature, unless otherwise explicitly specified and limited, it should not be limitedly understood, for example, "on" or "under" can be that the first and second features are in direct contact, or the first feature and the second feature are indirectly in contact through an intermediate medium. For those of ordinary skill in the art, the specific meaning of the above description of terms in the present application can be understood according to the specific circumstances, the context, the coherence of the preceding and following texts, etc.

[0080] Further, the first feature "on", "above" and "above" the second feature can be directly above or obliquely above the second feature, or only indicate that the first feature is higher than the second feature in horizontal height. The first feature "under", "below" and "below" the second feature can be directly below or obliquely below the second feature, or only indicate that the first feature is lower than the second feature in horizontal height.

[0081] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In the present application, the illustrative description of the above terms is not necessarily for the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any suitable manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine different embodiments, examples and features of different embodiments, examples described in the present application without contradiction, which should be included in the scope of the present application.

[0082] Although the embodiments of the present application have been shown and described above, it should be understood that the above embodiments are exemplary and should not be construed as limiting the present application. Within the scope of information available to the public, those skilled in the art can make changes, modifications, replacements and variations to the above embodiments in combination with the technical inspiration given in the present application file.

Claims

1. A 3N+3N stepped variable transmission system characterized by: The transmission comprises an input shaft (1), a first intermediate shaft (2), a second intermediate shaft (3), and an output shaft (4). The input shaft (1) and the first intermediate shaft (2) are connected through a forward-reverse gear shifting mechanism. The first intermediate shaft (2) and the second intermediate shaft (3) are connected through a multi-gear shifting mechanism. The second intermediate shaft (3) and the output shaft (4) are connected through a high-low gear shifting mechanism. A middle driving wheel is connected to the second intermediate shaft (3). A crawling gear driving wheel (39) is rotatably connected to the second intermediate shaft (3). A middle driven wheel and a crawling gear driven wheel (44) are rotatably connected to the output shaft (4). The outer periphery of the middle driven wheel is connected to the middle driving wheel. The hub of the middle driven wheel is connected to the outer periphery of the crawling gear driving wheel (39). The hub of the crawling gear driving wheel (39) is connected to the crawling gear driven wheel (44). The crawling gear driven wheel (44) is provided with a crawling gear shifter (45) on one side, which is connected to the output shaft (4). The hubs of the middle driven wheel and the crawling gear driving wheel (39) are provided with external teeth.

2. The 3N+3N range transmission system of claim 1, wherein: The high-low gear shifting mechanism comprises a low gear driving wheel (37) and a high gear driving wheel (38), which are both connected to the second intermediate shaft (3). The high-low gear shifting mechanism also comprises a low gear driven wheel (41) and a high gear driven wheel (42), which are rotatably connected to the output shaft (4). The low gear driven wheel (41) is connected to the low gear driving wheel (37), and the high gear driven wheel (42) is connected to the high gear driving wheel (38). A high-low gear synchronizer (43) is arranged between the low gear driven wheel (41) and the high gear driven wheel (42), and is connected to the output shaft (4).

3. The 3N+3N range transmission system of claim 2, wherein: The low gear driving wheel (37), the high gear driving wheel (38), the low gear driven wheel (41), and the high gear driven wheel (42) are all gears. The low gear driving wheel (37) is the same gear as the middle driving wheel, and the low gear driven wheel (41) is the same gear as the middle driven wheel.

4. The 3N+3N range transmission system of claim 1, wherein: The forward-reverse gear shifting mechanism comprises a reverse gear driving wheel (11), a forward gear driving wheel (12), a reverse gear driven wheel (21), and a forward gear driven wheel (22). The reverse gear driving wheel (11) is connected to the reverse gear driven wheel (21) through an idler wheel (5). The forward gear driving wheel (12) is connected to the forward gear driven wheel (22). The reverse gear driving wheel (11) and the forward gear driving wheel (12) are both connected to the input shaft (1). The reverse gear driven wheel (21) and the forward gear driven wheel (22) are rotatably connected to the first intermediate shaft (2). A forward-reverse gear synchronizer (23) is arranged between the reverse gear driven wheel (21) and the forward gear driven wheel (22), and is connected to the first intermediate shaft (2).

5. The 3N+3N range transmission system of claim 4, wherein: The reverse drive gear (11), the forward drive gear (12), the reverse driven gear (21), the forward driven gear (22) and the idler gear (5) are all gears, one side of the teeth of the idler gear (5) meshes with the reverse drive gear (11), and the other side of the teeth meshes with the reverse driven gear (21).

6. The 3N+3N range transmission system of claim 5, wherein: The shaft center of the reverse drive gear (11), the shaft center of the reverse driven gear (21) and the shaft center of the idler gear (5) are parallel to each other and not in the same plane.

7. The 3N+3N range transmission system of claim 5, wherein: The reverse drive gear (11) and the forward drive gear (12) are both transmissionally coupled with the input shaft (1) through the spline structure.

8. The 3N+3N range transmission system of claim 1, wherein: The multi-gear shifting mechanism comprises a first gear drive gear (24), a second gear drive gear (25), a third gear drive gear (26) and a fourth gear drive gear (27) which are all transmissionally coupled with the first intermediate shaft (2), and comprises a first gear driven gear (31), a second gear driven gear (32), a third gear driven gear (33) and a fourth gear driven gear (34) which are all rotatably sleeved on the second intermediate shaft (3), the first gear driven gear (31) is transmissionally coupled with the first gear drive gear (24), the second gear driven gear (32) is transmissionally coupled with the second gear drive gear (25), the third gear driven gear (33) is transmissionally coupled with the third gear drive gear (26), and the fourth gear driven gear (34) is transmissionally coupled with the fourth gear drive gear (27). A first-second gear synchronizer (35) is arranged between the first gear driven gear (31) and the second gear driven gear (32), a third-fourth gear synchronizer (36) is arranged between the third gear driven gear (33) and the fourth gear driven gear (34), and the first-second gear synchronizer (35) and the third-fourth gear synchronizer (36) are both transmissionally coupled with the second intermediate shaft (3).

9. The 3N+3N range transmission system of claim 8, wherein: The first gear drive gear (24), the second gear drive gear (25), the third gear drive gear (26), the fourth gear drive gear (27), the first gear driven gear (31), the second gear driven gear (32), the third gear driven gear (33) and the fourth gear driven gear (34) are all gears.

10. The 3N+3N range transmission system of claim 9, wherein: The first gear drive gear (24) and the second gear drive gear (25) are fixed on the first intermediate shaft (2), and the third gear drive gear (26) and the fourth gear drive gear (27) are both transmissionally coupled with the first intermediate shaft (2) through the spline structure.

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