CN115416483A - Variable speed transmission device and vehicle provided with same - Google Patents

Abstract

The invention relates to the field of vehicles and discloses a speed change transmission device and a vehicle with the same, wherein the speed change transmission device comprises a transmission shell (K1), a main speed change gear set (3), an auxiliary speed change gear set (4), a rear axle driving shaft (51) and a front axle driving shaft (52), the transmission shell (K1) is provided with a front supporting wall (B1), a middle supporting wall (B2) and a rear supporting wall (B3) positioned at the rear end, and the front axle driving shaft (52) is pivotally mounted on the rear supporting wall (B3) to reserve a space for arranging a speed change gear and a transmission gear on the rear axle driving shaft (51). The variable speed transmission device can avoid occupying the space of a second chamber (S2) between the middle supporting wall and the rear supporting wall, so that the space for arranging the low-speed driven gear, the front axle driving shaft driving gear and the like can be reserved in the second chamber, and the limitation of the supporting wall on the arrangement and installation of the variable speed gear and the transmission gear is effectively reduced.

Description

Variable speed transmission device and vehicle provided with same

Technical Field

The invention relates to the field of vehicles, in particular to a variable speed transmission device. On the basis, the invention also relates to a vehicle provided with the variable speed transmission device.

Background

Generally, a tractor uses a diesel engine as a power unit to provide power for driving walking, work, and the like. The diesel engine is reasonably distributed to the driving wheel, the power take-off (PTO), the hydraulic pump and other working devices after passing through the transmission device through the power (namely torque and rotating speed) output by the crankshaft and the flywheel, thereby realizing various agricultural operation functions of the tractor.

After the power output by the engine is reversed and changed in speed, the power is distributed to a rear axle and a front axle through a rear axle driving shaft and a front axle driving shaft so as to drive the tractor to run, wherein the rear axle driving shaft and the front axle driving shaft are pivotally installed in a transmission device, and the supporting mode of the rear axle driving shaft and the front axle driving shaft has important influence on the design, processing and assembly of the transmission. For example, the support walls used to support these drive shafts may affect the arrangement and mounting of the speed change gears and the transfer gears.

Disclosure of Invention

The invention aims to overcome the problem that the support wall for supporting the driving shaft in the prior art has adverse effect on the arrangement and installation of the speed change gear and the transmission gear, and provides a speed change transmission device which can effectively reduce the limitation of the support wall on the arrangement and installation of the speed change gear and the transmission gear.

To achieve the above object, one aspect of the present invention provides a variable speed transmission comprising:

a transmission housing having a first end for connection to a drive device and a second end opposite the first end, and having a rear support wall at the second end, a middle support wall spaced from the rear support wall, and a front support wall disposed closer to the first end than the middle support wall disposed therein to divide an interior cavity of the transmission housing into a first chamber relatively closer to the first end and a second chamber relatively closer to the second end by the middle support wall;

a main shift gear group installed into the second chamber through a main shift gear shaft having both ends pivotally installed at the intermediate support wall and the rear support wall, respectively, the main shift gear shaft including a driving shaft and an intermediate shaft extending in parallel with each other, the main shift gear group including a plurality of pairs of shift gears provided at the driving shaft and the intermediate shaft to be engaged with each other, so that the intermediate shaft can have different gear ratios with respect to the driving shaft by switching a coupling relationship of the shift gears with the driving shaft;

a sub-transmission gear set including a low-speed driven gear and a high-speed driven gear respectively engaged with a low-speed drive gear and one of the speed change gears provided on the intermediate shaft;

a rear axle drive shaft on which a front axle drive shaft drive gear is provided, and a front axle drive shaft on which a front axle drive shaft driven gear engaged with the front axle drive shaft drive gear is provided and which is pivotally mounted to the rear support wall to leave a space in the second chamber in which the low-speed driven gear, the high-speed driven gear, and the front axle drive shaft drive gear are disposed.

Preferably, a transmission cover plate is mounted on the transmission housing, a main transmission operating mechanism for operating the main transmission gear set to form different transmission ratios is mounted on the transmission cover plate, and an auxiliary transmission operating mechanism for operating the auxiliary transmission gear set to form different transmission ratios is mounted on the rear support wall and the middle support wall.

A second aspect of the invention provides a vehicle provided with the above-described speed change transmission device.

Preferably, the vehicle may be a tractor, the second end of the transmission housing is detachably connected with a hydraulic pump mounting housing formed with a hydraulic pump mounting seat for mounting a hydraulic pump, the first end of the transmission housing is connected to the engine housing, and the end of the hydraulic pump mounting housing remote from the transmission housing is connected to the rear axle housing.

Through the technical scheme, the rear end supporting point of the front axle driving shaft is arranged on the rear supporting wall positioned at the second end of the transmission shell, so that the space of a second chamber between the middle supporting wall and the rear supporting wall is avoided being occupied, the space for arranging the low-speed driven gear, the front axle driving shaft driving gear and the like can be reserved in the second chamber, and the limitation of the supporting wall on the arrangement and installation of the speed changing gear and the transmission gear is effectively reduced.

Drawings

FIG. 1 is a schematic cross-sectional view of a variable speed drive according to a preferred embodiment of the present invention.

Description of the reference numerals

1-a power input shaft of a travelling mechanism; 2-a reversing gear set; 20-a reversing shaft; 21-a forward output gear; 22-reverse output gear; 23-reversing the first transfer gear; 24-reverse second drive gear; 25-a walking input gear; 3-a main gear set; 30-a main gear shaft; 30 a-a drive shaft; 30 b-an intermediate shaft; 31 a-first speed drive gear; 31 b-a second speed drive gear; 31 c-first speed driven gear; 31 d-a second speed driven gear; 4-auxiliary speed change gear set; 41-low speed drive gear; 42-low speed driven gear; 43-high speed driven gear; 5-a walking power output shaft; 51-rear axle drive shaft; 52-front axle drive shaft; 61-front axle drive shaft drive gear; 62-front axle drive shaft driven gear; 7-PTO drive shaft; 81-hydraulic pump mount; 82-spline housing; 83-driven bevel gear shaft; 84-driven bevel gear shaft mounting seats; 85-driven bevel gear; 86-drive bevel gear; 87-drive bevel gear support seats; k1-transmission housing; k2-hydraulic pump mounting housing; b1-a front support wall; b2-intermediate support wall; b3-rear supporting wall; s1-a first chamber; s2-a second chamber.

Detailed Description

The following describes in detail embodiments of the present invention with reference to the drawings. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.

Referring to fig. 1, a variable speed transmission according to a preferred embodiment of the present invention may be used in a tractor to transmit power generated from an engine to working devices such as a driving wheel, a PTO, and a hydraulic pump. To this end, the speed change transmission may be connected, for example, at an end (e.g., the front end) toward the engine to the crankshaft and flywheel of the engine, wherein the crankshaft of the engine may be directly connected to the PTO drive shaft 7, and the rear end of the PTO drive shaft 7 may drive rotation of a PTO output shaft (not shown) via splines; meanwhile, the PTO drive shaft 7 may further be splined to a drive bevel gear 86 provided thereon, the drive bevel gear 86 being engaged with a driven bevel gear 85, and a driven bevel gear shaft 83 provided with the driven bevel gear 85 being connected to an input shaft of a hydraulic pump (not shown) through a spline housing, wherein the hydraulic pump may be mounted to the hydraulic pump mount 81 so as to distribute a part of power output from the engine crankshaft to the hydraulic pump. The engine flywheel can be connected with the power input shaft 1 of the walking mechanism in an on-off mode through a clutch, power input by the power input shaft 1 of the walking mechanism can be sequentially reversed and regulated through the reversing gear set 2, the main speed change gear set 3 and the auxiliary speed change gear set 4, and finally transmitted to the walking power output shaft 5 (such as a rear axle driving shaft 51 and a front axle driving shaft 52) to drive the tractor to walk.

As is apparent from the above description of the entire variable speed transmission device according to the present invention, the variable speed transmission device mainly includes the following functional modules: a reversing and speed-changing transmission part for transmitting power generated by the engine to a driving wheel through a reversing gear set 2, a main speed-changing gear set 3, etc.; a PTO transmission portion for transmitting power generated by the engine to a PTO output shaft through a PTO drive shaft 7; and a hydraulic pump driving part for distributing a part of the power transmitted from the PTO drive shaft 7 to the hydraulic pump. These parts are mainly arranged and mounted in housing parts, i.e., the transmission housing K1 and the hydraulic pump mounting housing K2 of the speed change transmission device of the present invention, to reliably support the transmission parts of the respective function modules.

To this end, the variable speed drive may comprise a transmission assembly, which may have a transmission housing K1. For clarity of illustration, the transmission case K1 has two ends respectively described as a first end and a second end, the first end and the second end being opposite to each other, wherein the first end can be used for connecting to a case of a driving device (such as an engine) by, for example, a bolt, and the second end is connected to a hydraulic pump mounting case K2. And the end of the hydraulic pump mounting case K2 remote from the transmission case K1 may be connected to a rear axle case, thereby collectively constituting a chassis of the tractor.

Wherein the hydraulic pump mounting case K2 is detachably connected to the second end of the transmission case K1 by, for example, bolts, and the hydraulic pump mounting case K2 is formed thereon with a driven bevel gear shaft mounting seat 84 and a hydraulic pump mounting seat 81 which are coaxially disposed with each other, and the driven bevel gear shaft 83 provided with a driven bevel gear 85 is rotatably mounted on the driven bevel gear shaft mounting seat 84. From this, because driven bevel gear axle mount pad 84 and hydraulic pump mount pad 81 all set up on this hydraulic pump installation casing K2 to can guarantee the axiality between the central axis of driven bevel gear 85 and hydraulic pump input shaft easily in processing and assembly, avoid the unusual atress of transmission part from this, thereby reduce the risk that phenomenons such as noise, jamming appear, and guarantee the life of transmission part and hydraulic pump.

In order to obtain power for driving the hydraulic pump using the PTO drive shaft 7, the PTO drive shaft 7 may be provided to extend through the transmission case K1 and the hydraulic pump mounting case K2, and provided with a drive bevel gear 86 at a portion penetrating into the hydraulic pump mounting case K2. The drive bevel gear 86 is provided to be engaged with the driven bevel gear 85 so as to be able to transmit the rotational power of the PTO drive shaft 7 to the hydraulic pump mounted on the hydraulic pump mount 81. Here, because set up driven bevel gear axle mount 84 in hydraulic pump installation casing K2, and hydraulic pump installation casing K2 detachably is connected to derailleur casing K1, when the meshing position of the initiative bevel gear 86 that needs to be changed or adjusted, only need break off the connection of hydraulic pump installation casing K2 and gearbox casing K1 and can change or adjust, and need not to dismantle hydraulic pump and driven bevel gear 85 etc. alone, effectively simplified its dismouting process.

According to the above, the speed change transmission of the present invention has the driven bevel gear shaft mount 84 provided on the hydraulic pump mount case K2, whereby the coaxiality with respect to the hydraulic pump mount 81 can be secured by, for example, machining with the same reference as the hydraulic pump mount 81. Among them, the driven bevel gear shaft mount 84 may be provided to the hydraulic pump mounting case K2 in various suitable manners, such as being separately machined from the other portions of the hydraulic pump mounting case K2, and being positioned and assembled as one body. In a preferred embodiment of the present invention, the top wall of the hydraulic pump mounting case K2 is formed to protrude downward as a driven bevel gear shaft mounting seat 84, and a hydraulic pump mounting seat 81 is provided on a side wall of the hydraulic pump mounting case K2 for the sake of convenience of layout, thereby enabling machining with the same reference and ensuring the coaxiality of the two, thereby enabling to secure a high coaxiality between the driven bevel gear 85 and the central axis of the input shaft of the hydraulic pump after being mounted, thereby avoiding abnormal stress of the transmission parts.

Among them, the driven bevel gear shaft 83 provided with the driven bevel gear 85 may be provided to have a small extension with respect to a space between the hydraulic pump mount 81 and the driven bevel gear shaft mount 84, thereby enabling convenient installation. In this case, the driven bevel gear shaft 83 may be drivingly connected to the input shaft of the hydraulic pump between the hydraulic pump mount 81 and the driven bevel gear shaft mount 84 through the spline housing 82.

With continued reference to fig. 1, the PTO drive shaft 7 extends through the transmission case K1 and the hydraulic pump mounting case K2, and on the extending path thereof, the PTO drive shaft 7 should be reasonably supported to be able to stably transmit power. For this reason, a plurality of support walls (front support wall B1, intermediate support wall B2, and rear support wall B3) may be formed or installed in the transmission case K1, and the number of support walls is not so large as to occupy a limited space in the transmission case K1 and affect the arrangement of the transmission gears and the like.

Wherein, the second end of the transmission case K1 may be provided with a rear supporting wall B3, and a drive bevel gear supporting seat 87 is formed at a side of the rear supporting wall B3 facing the hydraulic pump mounting case K2. Thus, the PTO drive shaft 7 can be extended through the drive bevel gear support base 87 into the hydraulic pump mounting case K2, and the drive bevel gear 86 is rotatably supported by the drive bevel gear support base 87. When it is necessary to adjust or replace the meshing position of the drive bevel gear 86, the hydraulic pump mounting case K2 can be detached from the transmission case K1 together with the hydraulic pump mounted thereon, the driven bevel gear shaft 83, the driven bevel gear 85, and the like, without separately detaching the driven bevel gear 85 and the like from the hydraulic pump mounting case K2.

In the preferred embodiment shown, the running gear power input shaft 1 and the PTO drive shaft 7 extend through a first end of the transmission housing K1 for direct or indirect connection to the engine. As described above, in order to perform a traveling function of the tractor, the traveling mechanism power input shaft 1 is drivingly connected to the traveling power output shaft 5 through the reversing gear set 2 and the main transmission gear set 3 to be able to drive the wheels to rotate in different directions or at different gear ratios, thereby changing the traveling speed and traction of the tractor or causing the tractor to travel in reverse without changing the rotational direction of the engine. The reversing gear set 2 and the main gear set 3, and subsequently the auxiliary gear set, are each disposed in the transmission housing K1, and can be shifted by a suitable actuating mechanism. The reversing gear set 2 can be switched to rotate the walking power output shaft 5 in different directions, so that the tractor can be switched between forward and reverse travel; the main gear change set 3 can be switched such that the running power take-off shaft 5 has a different transmission ratio with respect to the running gear power take-off shaft 1, so that the tractor has different running speeds and tractive forces.

Wherein a front support wall B1, an intermediate support wall B2 and a rear support wall B3 are formed or mounted in the transmission housing K1 in order to arrange and support the reversing gear set 2 and the main gear set 3 reasonably. As mentioned above, the rear support wall B3 is located at the second end of the transmission case K1, the middle support wall B2 is spaced from the rear support wall B3, and the front support wall B1 is located closer to the first end of the transmission case K1 than the middle support wall B2. Thus, the inner cavity of the transmission case K1 is partitioned into a plurality of regions, and the front and rear both side spaces partitioned by the intermediate support wall B2 are referred to as a first chamber S1 and a second chamber S2, respectively, that is, a region located between the front support wall B1 and the intermediate support wall B2 is the first chamber S1, and a region located between the intermediate support wall B2 and the rear support wall B3 is the second chamber S2. The drive shafts (e.g., the running gear power input shaft 1, the reversing shaft 20, the main gear shaft 30) for mounting the reversing gear set 2 and the main gear set 3 can be pivotally mounted on these support walls by bearings such that the reversing gear set 2 is located in the first chamber S1 and the main gear set 3 and the range gear set 4 can be located in the second chamber S2.

The middle support wall B2 may be integrally formed in the transmission case K1, such as by integral casting and machining, so as to reliably support the transmission component and avoid additional increase in processing difficulty; the front and rear support walls B1 and B3 are respectively removably mounted (e.g., by fasteners) into the transmission housing K1, thereby facilitating mounting of the reversing gear set 2 and the main gear set 3 into the first and second chambers S1 and S2. In another embodiment, the intermediate support wall B2 may be formed separately from the transmission case K1 and integrally connected by a fastener.

In the illustrated preferred embodiment, the travelling mechanism power input shaft 1 is formed as a hollow shaft and is sleeved on the PTO drive shaft 7, whereby different functional modules for transmitting travelling power and working power in the transmission can be compactly arranged, avoiding that the transmission is heavy due to large space occupation.

The reversing gear set 2 may be provided in a suitable form to form a forward drive path and a reverse drive path. In the illustrated preferred embodiment, the reversing gear set 2 includes a forward output gear 21 and a reverse output gear 22 mounted on the running gear power input shaft 1, and the forward output gear 21 and the reverse output gear 22 may be controlled by a synchronizer to be selectively engaged to the running gear power input shaft 1 to transmit running power backward by one of them. Wherein the forward output gear 21 is in constant mesh with a travel input gear 25 provided on the main transmission gear shaft 30 (the motive shaft 30 a), wherein the travel input gear 25 is provided on a portion of the main transmission gear shaft 30 (the motive shaft 30 a) extending into the first chamber S1. Thus, when switching is made such that the forward output gear 21 is engaged to the running mechanism power input shaft 1, the main transmission gear shaft 30 can be driven to rotate in the reverse direction with respect to the running mechanism power input shaft 1, and the wheels are driven to rotate by the subsequent running power output shaft 5, whereby the forward movement of the tractor is realized.

In the first chamber S1, a reversing shaft 20 extending in parallel with the running gear power input shaft 1 is further provided, and both ends of the reversing shaft 20 are pivotally mounted to the front support wall B1 and the intermediate support wall B2, respectively, and a reverse first transmission gear 23 constantly meshing with the reverse output gear 22 and a reverse second transmission gear 24 constantly meshing with the aforementioned running input gear 25 are mounted thereon. Thus, when switching is made such that the reverse output gear 22 is engaged to the running gear power input shaft 1, the main transmission gear shaft 30 is driven to rotate in the same direction as the running gear power input shaft 1 through the reverse first transmission gear 23, the reversing shaft 20, the reverse second transmission gear 24 and the running input gear 25 in this order, and the wheels are driven to rotate through the subsequent running power output shaft 5, thereby realizing the reverse of the tractor.

In a preferred embodiment of the speed change transmission of the present invention, the variator assembly is provided with a main speed change gearset 3 and an auxiliary speed change gearset 4 to enable a greater variety of gear ratios to be achieved to facilitate the tractor's adaptation to a variety of different walking conditions. To this end, a plurality of main transmission gear shafts 30 may be pivotally mounted on the intermediate support wall B2 and the rear support wall B3 so as to realize multiple speed changes by a plurality of sets of transmission gears during power transmission.

Specifically, as shown in connection with fig. 1, the main-gear shaft 30 may include a driving shaft 30a and an intermediate shaft 30B extending in parallel with each other, wherein the driving shaft 30a may pass through the intermediate support wall B2 to mount the aforementioned walking input gear 25 for receiving the power transmitted from the reversing gear set 2 at a portion penetrating into the first chamber S1. A plurality of pairs of speed change gears 31a-31d may be provided on the axle shaft 30a and the intermediate shaft 30b and disposed to be located in the second chamber S2 to enable the intermediate shaft 30b to have different gear ratios with respect to the axle shaft 30a by switching the engagement relationship of the speed change gears 31a-31d with the axle shaft 30 a. It is to be understood that although six pairs of speed change gears are shown on the main shaft 30a and the intermediate shaft 30b, the speed change transmission of the present invention may have the number of pairs of speed change gears increased or decreased as necessary, such as four pairs or eight pairs. For clarity of illustration, only two pairs of adjacent speed change gears, i.e., a first-speed drive gear 31a and a first-speed driven gear 31c that are in constant mesh with each other and a second-speed drive gear 31b and a second-speed driven gear 31d that are in constant mesh with each other, are labeled in fig. 1. Wherein the first speed drive gear 31a and the second speed drive gear 31b are provided on the drive shaft 30a and can be controlled by a synchronizer to be selectively engaged with the drive shaft 30 a; the first-speed driven gear 31c and the second-speed driven gear 31d are provided on the intermediate shaft 30b and are constantly engaged with the intermediate shaft 30b (e.g., splined or integrally formed), respectively. Thus, when manipulated such that the first speed drive gear 31a is engaged with the driveshaft 30a, the power transmitted by the driveshaft 30a can be transmitted to the counter shaft 30b through the first speed driven gear 31 c; when manipulated such that the second-speed drive gear 31b is engaged with the driveshaft 30a, the power transmitted from the driveshaft 30a can be transmitted to the counter shaft 30b through the second-speed driven gear 31d.

In the illustrated preferred embodiment, as with the running gear power input shaft 1, the intermediate shaft 30B is also formed as a hollow shaft and is fitted over the PTO drive shaft 7, with both ends pivotally mounted to the intermediate support wall B2 and the rear support wall B3, respectively, by bearings. Thereby, the transmission gears 31a to 31d can be arranged compactly in the second chamber S2 with respect to other portions, avoiding the transmission gear from being bulky due to occupying a large space.

Further, some of the speed change gears 31a-31d on the intermediate shaft 30b may be used as part of the sub-speed change gear set 4, as shown by the second speed driven gear 31d, which meshes with the high speed driven gear 43 provided on the walking power output shaft 5 (rear axle drive shaft 51). Further, a low-speed drive gear 41 may be formed or mounted on the intermediate shaft 30b, and the diameter and the number of teeth of the low-speed drive gear 41 are smaller than those of the aforementioned second-speed driven gear 31d, and mesh with a low-speed driven gear 42 provided on the traveling power output shaft 5 (rear axle drive shaft 51). Wherein, for switching between high and low speeds, the low-speed driven gear 42 and the high-speed driven gear 43 are arranged to be selectively engaged to the walking power take-off shaft 5 (rear axle drive shaft 51) to which they are located, as by synchronizers. Thus, when the low-speed driven gear 42 is engaged to the traveling power output shaft 5, the power transmitted by the intermediate shaft 30b is transmitted to the traveling power output shaft 5 through the low-speed drive gear 41 and the low-speed driven gear 42; when the high-speed driven gear 43 is engaged to the traveling power output shaft 5, the power transmitted by the intermediate shaft 30b is transmitted to the traveling power output shaft 5 through the second-speed driven gear 31d and the high-speed driven gear 43.

The gear change transmission may be provided with two walking power take-off shafts 5 to have a two-drive or four-drive or the like walking drive mode. The traveling power output shaft 5 may be pivotally mounted on the front support wall B1, the intermediate support wall B2, and the rear support wall B3 in the transmission case K1 through bearings. In the illustrated preferred embodiment, the traveling power output shaft 5 includes a rear axle drive shaft 51 and a front axle drive shaft 52, and the low-speed driven gear 42 and the high-speed driven gear 43 in the aforementioned range gear set 4 are mounted to the rear axle drive shaft 51, and the rear axle drive shaft 51 extends rearward through the rear support wall B3 for drivingly connecting the rear axle.

A front axle drive shaft driving gear 61 is provided on the rear axle drive shaft 51, and a front axle drive shaft driven gear 62 meshed with the front axle drive shaft driving gear 61 is provided on the front axle drive shaft 52. The front axle drive shaft 52 is pivotally mounted to the front support wall B1 and the rear support wall B3, respectively, at spaced locations from each other, and extends forwardly through the front support wall B1 for driving connection with the front axle. Since the low-speed driven gear 42 in the sub-transmission gear set 4 and the front axle drive shaft drive gear 61 on the rear axle drive shaft 51 have relatively large dimensions, by providing the front axle drive shaft 52 to be pivotally mounted to the rear support wall B3 at the second end of the transmission case K1, it is possible to leave a space in the second chamber S2 for arranging the low-speed driven gear 42 (and the high-speed driven gear 43) and the front axle drive shaft drive gear 61, avoiding the possibility of interference. Also, by providing the rear support wall B3 to be detachably connected to the transmission case K1, the disassembly and maintenance of these gear members can be facilitated.

On the front axle drive shaft 52, a front axle drive disconnecting unit (not labeled) for cutting off power transmission may be provided to enable switching from four-drive to two-drive by cutting off transmission of engine power to the front axle by the front axle drive disconnecting unit when necessary.

In the shift transmission device according to a preferred embodiment of the present invention, a transmission cover plate (not shown) on which a main shift operating mechanism for operating the main shift gear set 3 to form different gear ratios is mounted may be mounted on the transmission case K1, and sub-shift operating mechanisms for operating the sub-shift gear set 4 to form different gear ratios may be mounted on the rear support wall B3 and the intermediate support wall B2. From this, only need guarantee main variable speed operating mechanism's correct installation when assembling derailleur apron to derailleur casing K1, effectively avoided increasing because of the assembly degree of difficulty that sets up vice variable speed operating mechanism and lead to. Because the mounting structure for the auxiliary transmission control mechanism is not required to be arranged on the transmission cover plate, the structure of the transmission cover plate can be relatively simple, the design freedom degree is higher, and the processing difficulty is lower.

It is to be understood that although the main and sub-transmission gear sets 3 and 4 are described herein as being operated, the objects of operation of the main and sub-transmission operating mechanisms are not limited to the gears themselves, such as the fork openings of the forks thereof may be caught in the ring grooves of the synchronizer sleeves provided on the gear side to achieve a shift operation by operating the synchronizer sleeves. Alternatively, the fork opening of the shift fork may be caught in a ring groove of the sliding gear to directly manipulate so that the sliding gear slides in the axial direction to perform a shifting operation.

The mounting structure of the main shift operating mechanism on the transmission cover plate may be a typical mounting form, such as including a main shift rail mounted to the inner side of the transmission cover plate and a main shift fork connected to the main shift rail, which can be operated to switch the transmission path of the main gear set 3 and form different transmission ratios. In addition, the main shift control mechanism may further include other parts of a shift fork mechanism such as a shift lever, and a positioning and locking device or the like for accurately locking the main shift fork shaft and the main shift fork at a shift position.

Similarly, the range operating mechanism may include a range shift rail located in the internal cavity of the transmission case K1 and a range shift fork connected to the range shift rail. Wherein both ends of the sub-transmission shift rail are respectively mounted to the intermediate support wall B2 and the rear support wall B3. Therefore, the structure and assembly of the auxiliary speed changing shifting fork shaft and the auxiliary speed changing shifting fork are independent of the transmission cover plate, so that the assembly difficulty increase and the structure complication of the transmission cover plate caused by the arrangement of the auxiliary speed changing control mechanism can be avoided.

On this basis, the invention also relates to a vehicle, such as a tractor, provided with the above-described variable speed transmission provided by the invention, wherein a first end of a transmission housing K1 of the variable speed transmission is connected to an engine housing, and an end of a hydraulic pump mounting housing K2 remote from the transmission housing K1 is connected to a rear axle housing.

The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, numerous simple variants are possible, comprising the combination of the individual specific technical features in any suitable manner. The invention is not described in detail in order to avoid unnecessary repetition. Such simple modifications and combinations should also be considered as disclosed in the present invention, and all such modifications and combinations are intended to be included within the scope of the present invention.

Claims (10)

1. A variable speed drive, comprising:

a transmission case (K1), the transmission case (K1) having a first end for connecting to a drive device and a second end opposite to the first end, and a rear support wall (B3) at the second end, a middle support wall (B2) spaced apart from the rear support wall (B3), and a front support wall (B1) disposed closer to the first end than the middle support wall (B2) are provided in the transmission case (K1) to divide an inner cavity of the transmission case (K1) into a first chamber (S1) relatively close to the first end and a second chamber (S2) relatively close to the second end by the middle support wall (B2);

a main transmission gear set (3) mounted to the second chamber (S2) through a main transmission gear shaft (30) having both ends pivotally mounted to the intermediate support wall (B2) and the rear support wall (B3), respectively, the main transmission gear shaft (30) including an axle shaft (30 a) and an intermediate shaft (30B) extending in parallel with each other, the main transmission gear set (3) including a plurality of pairs of transmission gears (31 a-31 d) provided to the axle shaft (30 a) and the intermediate shaft (30B) to mesh with each other, so that the intermediate shaft (30B) can have different gear ratios with respect to the axle shaft (30 a) by switching the engagement relationship of the transmission gears (31 a-31 d) with the axle shaft (30 a);

a sub-transmission gear set (4), the sub-transmission gear set (4) including a low-speed driven gear (42) and a high-speed driven gear (43) respectively meshing with a low-speed drive gear (41) and one of the speed change gears (31 a-31 d) provided on the intermediate shaft (30 b);

a rear axle drive shaft (51) and a front axle drive shaft (52), the low-speed driven gear (42) and the high-speed driven gear (43) being installed and selectively coupled to the rear axle drive shaft (51), and a front axle drive shaft drive gear (61) being provided on the rear axle drive shaft (51), a front axle drive shaft driven gear (62) engaged with the front axle drive shaft drive gear (61) being provided on the front axle drive shaft (52) and pivotally mounted to the rear support wall (B3) to leave a space in which the low-speed driven gear (42), the high-speed driven gear (43), and the front axle drive shaft drive gear (61) are arranged in the second chamber (S2).

2. A variable speed drive according to claim 1, wherein the front support wall (B1) and the rear support wall (B3) are detachably mounted to the transmission housing (K1), respectively, and the intermediate support wall (B2) is integrally formed in the transmission housing (K1).

3. A variable speed drive as claimed in claim 1, characterized in that it comprises a running gear power input shaft (1) extending through a first end of the transmission housing (K1) and a reversing gear set (2) mounted into the first chamber (S1), the reversing gear set (2) being switchable to rotate the rear axle drive shaft (51) and the front axle drive shaft (52) in different directions.

4. A variable-speed drive as claimed in claim 3, characterized in that it comprises a PTO drive shaft (7) which extends through the transmission housing (K1), the running gear power input shaft (1) being fitted on the PTO drive shaft (7).

5. A variable speed drive as claimed in claim 3, wherein the reversing gear set (2) comprises: a forward output gear (21) and a reverse output gear (22) mounted and selectively coupled to the traveling mechanism power input shaft (1), a reverse first transmission gear (23) and a reverse second transmission gear (24) mounted through a reversing shaft (20) extending in parallel with the traveling mechanism power input shaft (1) and pivotally mounted at both ends to the front support wall (B1) and the intermediate support wall (B2), respectively, and a traveling input gear (25) provided on a portion of the driving shaft (30 a) extending into the first chamber (S1), wherein the reverse first transmission gear (23) is engaged with the reverse output gear (22), and the traveling input gear (25) is simultaneously engaged with the forward output gear (21) and the reverse second transmission gear (24) to be capable of being switched such that the traveling input gear (25) rotates in different directions.

6. A variable speed drive as claimed in claim 1, wherein the front axle drive shaft (52) is pivotally mounted to the front support wall (B1) at a position spaced from the rear support wall (B3), the rear axle drive shaft (51) is pivotally mounted to the intermediate support wall (B2) and rear support wall (B3) respectively at a position spaced from each other, and the front axle drive shaft drive gear (61) and front axle drive shaft driven gear (62) are disposed adjacent to the rear support wall (B3).

7. A variable speed drive as claimed in claim 1, wherein a front axle drive disconnect unit is provided on the front axle drive shaft (52).

8. The variable speed drive according to claim 1, wherein a hydraulic pump mounting housing (K2) is detachably attached to the second end of the transmission housing (K1), and the hydraulic pump mounting housing (K2) is formed with a hydraulic pump mounting seat (81) for mounting a hydraulic pump.

9. A variable speed drive according to claim 1, wherein a transmission cover plate is mounted on the transmission housing (K1), on which a main speed operating mechanism for operating the main speed gear set (3) to form different transmission ratios is mounted, and a sub speed operating mechanism for operating the sub speed gear set (4) to form different transmission ratios is mounted on the rear support wall (B3) and the intermediate support wall (B2).

10. A vehicle, characterized in that the vehicle is provided with a variable speed transmission according to any one of claims 1 to 9.

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