JPH0214230B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an agricultural tractor of medium-sized (40 PS) class or less.

Conventionally, small and medium-sized tractors 1 have an integral structure in which an engine block 2 and a transmission case 3 are connected by a clutch housing 5 to form a tractor frame, as shown in FIG. In the tractor 1, the distance L between the front and rear wheels is limited to a certain range due to turning performance, etc.
Furthermore, the minimum ground height H has been increased to 400 due to rice field functions, etc.
It is held down to about mm. Furthermore, the height of the driver's seat 6 located on the transmission case 3 is limited to a certain level due to running stability, etc., and therefore the height h of the step 7 on which to place your feet is also limited to approximately 600 mm. There is. By the way, since the clutch housing 5 houses the transmission shaft and the like coaxially with the engine crankshaft, the top surface height of the clutch housing 5 is higher than the maximum step height h, and the housing 5 is not used during operation. It protrudes above the central part in front of the seat 6. Furthermore, since the transmission case 3 houses the main and auxiliary transmission gears, these change levers 9 and 10 are located close to the driver's seat 6.
It protrudes significantly upward in front of the.

Therefore, step 7 is the clutch housing 5
When getting on and off the driver's seat 6, the driver will have to look at the clutch housing 5 and transmission case 3, which protrude greatly.
It is very troublesome to have to step over the change levers 9 and 10. In particular, in recent years, tractor work has often been done by women and women, and women and women with small physiques have been forced to perform difficult operations. In addition, the driver had to put his feet on the narrow steps 7 that were divided into left and right sides, and his posture was fixed during operation, which caused great fatigue for the driver when driving for a long time.

Therefore, the present invention provides a main transmission and a
A front transmission case that houses the PTO gearbox is located, and a rear transmission case that houses the auxiliary transmission is located at the rear of the aircraft.
The front transmission case and the rear transmission case are connected by an intermediate case that houses the transmission shaft, and the upper surface of the intermediate case is a flat surface that is approximately the same plane as the step, and the step is connected to the intermediate case. It is fixed at the same time as it is extended before and after the
By fixing the front part to the front transmission case and the rear part to the rear transmission case,
It is an object of the present invention to provide a tractor that has a wide flat footrest in front of the driver's seat, thereby eliminating the above-mentioned drawbacks.

Embodiments based on the present invention will be described below with reference to the drawings.

As shown in FIGS. 2 and 3, the agricultural tractor 11 has a front chassis 13 mounted in front by a front wheel 12.
An engine block 2 supported together with the engine block 2 is arranged, and a rear transmission case 16 supported by a rear wheel 15 is arranged rearward. Furthermore,
A front transmission case 17 is fixed to the rear of the engine block 2, and the front transmission case 17 and rear transmission case 16 are connected by an intermediate case 19, and each case is combined to form a frame. It is constructed with an integral structure type. A driver's seat 6 is disposed on the rear transmission case 16, and an upper case 20 is disposed on the front transmission case 17, and the case 20 has a steering wheel 21 and a main shift lever 22 facing upward. and a PTO shift lever 23 are arranged. Further, the lower surface of the intermediate case 19 is aligned with the front transmission case 17 and the rear transmission case 16 to maintain a minimum ground height H, and the upper surface is held down so that the maximum step height h is maintained. This forms a flat surface 19a on which the driver's feet are placed. Further, steps 26 extend from both left and right sides of the intermediate case 19 so as to be at the same height as the upper surface 19a of the intermediate case, and each step 26 further extends to the left and right front of the front transmission case 17. The tip is bent upward to constitute a hot air shielding plate 26a, and the rear thereof extends to between the fenders 27 covering the left and right rear wheels 15 to constitute a mudguard plate 26b. Further, the step 25 is fixed to the front transmission case 17 via a stay 29 at the front thereof, and is fixed to the wheel boss 30 protruding left and right from the rear transmission case 20 via a stay at the rear thereof. has been done. In addition, 3 in the figure
1 is a muffler for the engine 15, 32 is a transmission shaft extending forward from the rear transmission case 16 for driving the front wheels 12, and 33 is a PTO shaft.
As shown in FIG. 4, the front transmission case 17 has a partition wall 17c so that the front part becomes the clutch chamber 17a and the rear part becomes the transmission gear chamber 17b.
A main clutch 35 is housed in the clutch chamber 17a, and a shaft 36 passes through the clutch 35 through the approximate center of the case 17 into the transmission gear chamber 17b, and rotates in alignment with the engine crank axis. freely supported. In addition, the transmission gear chamber 1
A traveling intermediate shaft 37 and a PTO intermediate shaft 39 are rotatably supported on the upper and lower sides of the main shaft 36, respectively, and four gears 40 with different numbers of teeth are fixed to the main shaft 36, and Axis 3
7 and the PTO intermediate shaft 39 have each gear 4 of the main shaft 36.
Each gear 41... and 42... which is always meshing with 0...
are each rotatably supported. Further, each gear 41... and 42... has an intermediate shaft 37,
The constant mesh selection clutches 43, 43 and 45, 45, which are slidably supported by the gear shift lever 39 and operated by the main shift lever 22 and the PTO shift lever 23, can selectively engage. Furthermore, a gear 46 is fixed to the end of the traveling intermediate shaft 37,
The gear 46 is connected to a gear 49 rotatably supported on the PTO intermediate shaft 39 via a gear 47 rotatably supported on the main shaft 36 . On the other hand, the intermediate case 19 rotatably supports a PTO intermediate shaft 39' and a traveling sleeve shaft 50 concentrically constituting a double transmission shaft, and both PTO intermediate shafts 39, 39' are aligned. The running sleeve shaft 50 is connected to the gear 49 via a joint. In this embodiment, the shafts 39' and 50 have a double shaft structure, but these shafts may be arranged parallel to each other in the intermediate case 19. Furthermore, PTO
The intermediate shaft 39' is aligned and connected to a PTO shaft 33 rotatably supported by the rear transmission case 16, and the PTO shaft 33 is connected to the rear transmission case 16.
It partially protrudes from the rear of the. The running sleeve shaft 50 is connected via a clutch 51 to a gear 52 that is loosely fitted to the PTO shaft 33 in the rear transmission case 16. An auxiliary transmission distribution shaft 53 is supported above, and an auxiliary transmission shaft 54 is rotatably supported above it. PTO axis 33
, each intermediate gear set 55... is rotatably supported on the auxiliary transmission distribution shaft 53, 56a, high speed gear set 56b, and low speed gear 56d are fixed, and intermediate speed gear 56c and very low speed gear 56e are fixedly supported. is rotatably supported on the sub-shift shaft 54, and is operated by a sub-shift lever 59 (FIGS. 2 and 3) protruding to the side of the driver's seat 6, and a distribution shaft 53 is supported on the sub-shift shaft 54.
A selection gear set 60 that can mesh with appropriate gears of the upper gear sets 56b...e is supported so as to be slidable only.
Further, a gear 61 is fixed to the sub-transmission shaft 54, and the gear 61 is connected to gears 62, 63 which are rotatably supported by the distribution shaft 53 and the PTO shaft 33, respectively.
It can be connected to a gear 66 that is slidably supported by the transmission shaft 32 and operated by a front wheel drive switching lever 65 via the front wheel drive switching lever 65 . Furthermore, the sub-shift shaft 5
A differential pinion 67 is formed at the tip of the differential gear 69.
It is connected to the left and right rear wheels 15 via etc.

Therefore, according to the present tractor 11, the engine 2
In the front transmission case 17, the rotation is changed to a predetermined speed through the main clutch 35, the main shaft 36, the gears 40, 41, and the mesh selection clutch 43 which is switched by the main shift lever 22, and the rotation is transferred to the traveling intermediate shaft 37. One side gears 40, 42 and
It is transmitted to the PTO intermediate shaft 39 via a mesh selection clutch 45 that is switched by the PTO gear shift lever 23. Furthermore, the rotation of the traveling intermediate shaft 37 is controlled by gears 46,
47 and 49, the rotation of the PTO intermediate shaft 39 is transmitted to the running sleeve shaft 50 inside the intermediate case 19, and the rotation of the PTO intermediate shaft 39 is transmitted to the PTO intermediate shaft 39' which is coaxially installed inside the sleeve shaft 50. , is transmitted to the rear transmission case 16. The rotation of the running sleeve shaft 50 is transmitted to the gear 52 via the clutch 51, and further to the gear 56a and the auxiliary transmission distribution shaft 53.
Or high, medium, low, and very low speed gears 56 that are rotated at different speeds through each gear set 55.
b, 56c, 56d, and 56e, and is further transmitted to the auxiliary transmission shaft 54 by meshing the selection gear set 60, which is switched by the auxiliary transmission lever 59, with any of these gears, and is further transmitted to the differential pinion 67 and the differential gear set 60. It is transmitted to the rear wheels 15 via a gear 69. At the same time, the rotation of the auxiliary transmission shaft 54 is transmitted to the transmission shaft 32 via the gears 61, 62, 63 and the gear 66 operated by the switching lever 65, and rotates the front wheel 12. Further, the rotation of the PTO intermediate shaft 39' is transmitted to the PTO shaft 33, which partially projects rearward from the case 16.

As explained above, according to the present invention, the front transmission case 17 that compactly houses the main clutch 35 and the PTO transmission gear is arranged at the front of the machine, and the auxiliary transmission, etc. is arranged at the rear of the machine. Rear transmission case 1 that compactly stores
6, and these front transmission case 17 and rear transmission case 16 are connected to transmission shafts 39',
50, the flat surface 19a is formed on the upper surface of the intermediate case 19 while maintaining the distance L between the front and rear wheels, the minimum ground height H, and the maximum step height h as before. In addition, since the speed change gear device is provided at the front of the machine, the main speed change lever 22 and the PTO speed change lever 23 can be placed in front of the flat surface 19a, and furthermore, they can be placed at the same height as the top surface of the intermediate case 19. By providing the step 26 at the bottom, a wide and flat footrest surface can be constructed. As a result, the driver can get on and off the vehicle without stepping over the clutch housing 5 and change levers 9, 10, which protrude significantly in the center in front of the driver's seat 6, as in the conventional case, and the step surface is a wide flat surface. This makes it comfortable to live in and reduces fatigue even when driven for long periods of time. In addition, the left and right steps 26 are fixed to the intermediate case 19 and extended to the front and rear, so that the front part is fixed to the front transmission case 17 and the rear part is fixed to the rear transmission case 16.
The step 26 constitutes a wide footrest surface in the front and acts as a reinforcing member to compensate for the strength reduced by the formation of the flat surface 19a. Furthermore, at this time, if the tip of the step 26 is bent upward, it will prevent the hot air from the engine from directly hitting your feet, forming a hot air shielding plate 26a, and if the rear end is brought into close contact with the fender 27, the rear wheel 15 will be protected. This can prevent mud from splashing onto the driver's seat 6. In addition, since the main transmission and PTO transmission gears are located at the front of the machine, the center of gravity of the tractor 11 moves forward, preventing accidents such as the tractor falling when starting or when there is excessive running resistance due to obstacles, etc. can be reduced.

[Brief explanation of drawings]

FIG. 1 is a side view showing a conventional tractor;
FIG. 2 is a plan view showing a tractor according to the present invention, FIG. 3 is a side view thereof, and FIG. 4 is a sectional view showing its transmission device. 11...Tractor, 2...Engine, 16...Rear transmission case, 17...Front transmission case,
19... Intermediate case, 19a... Flat surface, 26... Step, 26a... Hot air shielding plate, 26b... Mud guard plate,
27...Fender, 35...Clutch, 36-49
...speed change gear device, 39', 50...transmission shaft, 52~
60...Sub-transmission device.

Claims (1)

[Scope of Claims] 1. In a tractor having an integral structure in which cases are connected to form a frame, the front part houses a transmission gear device for main transmission and PTO transmission in an engine mounted at the front of the machine body. The transmission case is fixed to the rear transmission case, and the rear transmission case, which houses the auxiliary transmission and the like and has a driver's seat on top, is placed at the rear of the aircraft. The shafts are connected by an intermediate case that accommodates the shaft, and the upper surface of the intermediate case is a flat surface that is substantially the same plane as the step;
The tractor is constructed by fixing the step to the intermediate case and extending it to the front and rear, so that the front part is fixed to the front transmission case and the rear part is fixed to the rear transmission case. 2. The tractor according to claim 1, wherein the tip of the step is bent upward to serve as a hot air shielding plate, and the rear portion is closely attached to the fender to serve as a mudguard.