JPS6237765Y2 - - 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 been of an integral construction type, as shown in FIG. 1, in which an engine block 2 and a transmission case 3 are connected by a clutch housing 5 to form a tractor frame. The distance L between the front and rear wheels of the tractor 1 is limited to a certain range due to turning performance, etc., and the minimum ground height H is limited due to the paddy field function etc.
It is held down to about 400mm. 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 transmission shaft is housed in the clutch housing 5 in alignment 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 greatly above the center area of the foot of seat 6. Further, since the transmission case 3 houses the main and auxiliary transmission gears, the change levers 9 and 10 protrude significantly upward in front of the driver's seat 6. 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 bodies were 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 front transmission case, which houses the transmission gears for the main transmission and PTO transmission, is placed at the front of the machine, and a flat surface is formed on the upper surface of the intermediate case part, which is approximately the same plane as the step, to provide a flat and wide footrest. Tractors have been proposed in which the above-mentioned drawbacks are overcome. However, in this case, the engine also needs to be moved forward due to the arrangement of the front transmission case, but since the distance L between the front and rear wheels is limited, it is difficult to attach the front axle that supports the front wheels. It's causing problems.

Due to the above-mentioned circumstances, the present invention connects the front transmission case and the rear transmission case by an intermediate case part through which the transmission shaft that has been moved downward with respect to the engine crankshaft is inserted, and the upper surface of the intermediate case part is abbreviated as a step. Based on the fact that the crankshaft and the transmission shaft are separated from each other by the front transmission case,
The engine is moved upward, a chassis is extended in front of the engine, the front end of a center pin that pivots the front axle is supported on the front chassis, and the rear end of the center pin is positioned below the engine. The front axle is placed below the engine, allowing the front axle to be mounted even though the engine is moving forward, and without increasing the distance L between the front and rear wheels. It is an object of the present invention to provide a front axle mounting device for a tractor which can be provided with a flat footrest surface.

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

As shown in FIG. 2, the agricultural tractor 11 has a front transmission case 12 that houses a main clutch and a main transmission and PTO transmission gears at the front of the machine, and a sub-transmission and a sub-transmission at the rear of the machine.
A rear transmission case 15 housing the PTO shaft 13 and the like is arranged. Front transmission case 1
2 is fixed to the engine 2 at its front end, and connected to the rear transmission case 13 at its rear end via an intermediate case 17 that may be constructed separately or integrally, and each case is combined to form a frame. It is composed of an integral structural type forming a . The intermediate case 17 concentrically accommodates a traveling transmission shaft that connects the main transmission gear device and the sub-transmission device, and a PTO transmission shaft that connects the PTO transmission gear device and the PTO shaft 13. The transmission shaft is disposed downwardly relative to the crankshaft by a gear device in the front transmission case 12, and furthermore, the lower surface of the intermediate case 17 is aligned with the front transmission case 12 and the rear transmission case 15. It maintains a minimum ground height H, and its upper surface is pressed down to the maximum step height h, forming a flat surface 17a on which the driver's feet are placed. Further, steps 19 are fixedly installed from both left and right sides of the intermediate case 17 so as to be at the same height as the upper surface 17a of the intermediate case, and each step 19 extends to the left and right front of the front transmission case 12. Further, the rear thereof extends to between the fenders 21 covering the left and right rear wheels 20. Note that 23 in the figure is a front chassis fixed to the engine 2 toward the front of the aircraft body.

The front axle 26, which supports the front wheels 25 at its left and right ends, has the following features, as shown in detail in FIG.
Bearing part 2 provided in the longitudinal direction in the center part in the longitudinal direction
6a, and is comprised of a swing axle that is swingably supported around a center pin 27 fitted into the bearing portion 26a. In addition, the engine 2 is located at the front of the aircraft due to the front transmission case 12.
It has been shifted to the front of the fuselage compared to its conventional position, and since the alignment between the crankshaft and the transmission shaft has been severed due to the gear system inside the front transmission case 12, it has been shifted upward. There is. Therefore, the center pin 27 is fitted into and supported by an L-shaped bracket 31 that is detachably attached to the bottom surface of the oil pan 2a of the engine 2 with a bolt 30, and the center pin 27 is inserted into the center portion of the bracket 32 that extends over the front chassis 23. The boss portion 3 of the L-shaped bracket 35 is attached to the
By inserting the threaded portion 27a formed at the tip of the center pin 27 into the center pin 5a and further tightening and fixing with the nut 36, the front axle 26
The rear end of the center pin 27 is supported by the oil pan 2a at the lower end portion of the engine 2, and the front end of the center pin 27 is supported by the chassis 23.

Incidentally, in the event of a failure of the engine 2, it will be necessary to remove the oil pan 2a from the engine body and inspect the inside of the engine. The oil pan 2a can be disassembled without removing the entire oil pan 26. At this time, since no impact load or the like is applied to the front axle 26, sufficient front support can be provided only by the bracket 35.

As explained above, according to the present invention, the alignment relationship between the engine crankshaft and the power transmission shaft is severed by the gear device in the front transmission case 12, so that the engine 2 is moved upward and the power transmission shaft is moved downward. Since the rear end of the center pin 27 of the front axle 26 is supported at a position below the engine 2, the engine 2 can be placed forward. As a result, the distance L between the front and rear wheels,
While maintaining the minimum ground height H and maximum step height h as before, a flat surface 17 that is approximately the same plane as the step 19 is provided on the upper surface of the intermediate case portion 17.
It is possible to secure a. Furthermore, since the engine 2 is located in the front, the center of gravity of the tractor 11 can be moved forward to increase the load acting on the front wheels 25, which can prevent head build-up during work and improve four-wheel drive performance. In addition, it is possible to improve steering performance when working in wet fields. Furthermore, since the front axle 26 is disposed below the engine 2, the front wheel 25 is shifted downward relative to the engine 2 and the front chassis 23, so the width of the front wheel 25 in the horizontal direction becomes narrower. Engine 2 and chassis 2 in part
3, the steering angle of the front wheels 25 until they interfere with the engine 2 and the front chassis 23 can be significantly increased, and the turning radius of the tractor 11 can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a side view showing a conventional tractor;
FIG. 2 is a side view showing the tractor according to the present invention, and FIG. 3 is a sectional view showing the attachment portion of the front axle. 2...Engine, 2a...Lower end portion (oil pan), 11...Tractor, 12...Front transmission case, 15...Rear transmission case, 17
...Intermediate case part, 17a...Flat surface, 19...
Step, 23...Front chassis, 26...Front axle, 27...Center pin.

Claims (1)

[Scope of utility model registration request] The front transmission case is fixed to the engine at the front of the aircraft, and the rear transmission case is located at the rear of the aircraft, and the space between these front and rear transmission cases is moved downward relative to the engine crankshaft. The engine move upwards,
A front chassis extends to the front of the engine, supports the front end of a center pin that pivots the front axle on the front chassis, and supports the rear end of the center pin at a position below the engine. , a front axle mounting device for a tractor, in which the front axle is disposed below the engine.