JPH01127417A - Four-wheel-drive working vehicle - Google Patents

Abstract

PURPOSE:To eliminate heavy balance weight by securing a front wheel speed changer for changing speed of power of a transmission at the rear section of machine body and transmitting to front wheels to a machine body securing section at the rear section of front axle case located at front section of machine body. CONSTITUTION:A front axle case 11 is supported rollably around longitudinal axis P1 of machine body by means of a bracket 20 and a front wheel speed changer 10, while the input shaft of a differential mechanism in the front axle case 11 is coupled with the output shaft of the speed changer 10. Driving force is transmitted from a transmission 6 through a front wheel output shaft 15 to the front wheel speed changer 10 so as to switch the front wheel 1 between standard driving state and speed increase driving state. By such arrangement, front speed changer can be functioned effectively without requiring a heavy balance weight.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to the arrangement structure of a front wheel transmission in a four-wheel drive type working vehicle.

[Conventional technology]

In recent years, vehicles have been equipped with front wheel transmissions that can switch between a standard drive state in which power is transmitted to the front wheels at a drive speed that is approximately equal to the rear wheel drive speed, and an increased speed drive state in which power is transmitted to the front wheels at a drive speed greater than the rear wheel drive speed. Four-wheel-drive work vehicles are starting to appear. As a result, by switching the front wheel transmission to the speed-increasing drive side when turning, it is possible to easily make sharp turns without disturbing the ground, and even on soft ground.
An agricultural tractor, which is an example of such a work vehicle, has a front wheel transmission installed in the transmission at the rear of the machine, and when the steering wheel is turned beyond a set angle, the front wheel transmission increases speed. Some models are configured to be switched to the side.

[Problem that the invention seeks to solve]

As mentioned above, if the front wheel transmission, which is relatively heavy, is installed in the transmission at the rear of the machine, the weight at the rear of the machine tends to be heavier than the front. Working devices such as rotary tillers are often connected to the rear of the machine (
If the working device is connected to the rear part of the machine body in this way, the weight balance of the machine body will be further shifted to the rear side. If the load supported by the front wheels becomes too small in this way,
The driving force of the front wheels is no longer sufficiently transmitted to the ground, reducing the advantage of four-wheel drive, and the effectiveness of the front wheel transmission is lost.

Therefore, in order to prevent the above-mentioned problems, it is necessary to attach a balance weight of sufficient weight to the front of the aircraft, but this is not a preferable measure because it increases the weight of the entire aircraft.

The present invention has focused on the above-mentioned problem, and aims to provide a structure that can fully utilize the effectiveness of a front wheel transmission without any problems, even without installing particularly heavy balance weights. .

Means for Solving Problem C] The feature of the present invention is that in the four-wheel drive type work vehicle as described above, the power transmitted from the transmission provided at the rear of the machine body to the freely steerable front wheels is transmitted to the front wheels. The front wheel transmission is equipped with a front wheel transmission that switches between a standard drive state in which the drive speeds of the rear wheels are approximately equal and an increased speed drive state in which the drive speed of the front wheels is greater than that of the rear wheels. It is connected and fixed to the fuselage fixed part at the rear of the front axle case, and its functions and effects are as follows.

[For production]

With the configuration described above, the center of gravity of the aircraft, which was biased towards the rear of the aircraft, will move to the front of the aircraft, making the support load of the front and rear wheels balanced without extreme bias. be able to.

Furthermore, for models with a rolling front axle case, a structure in which the front wheel transmission is connected to the front axle case is also considered.
In order to allow the front axle case to roll without any trouble, the input shaft and output shaft of the front wheel transmission are arranged in a straight line on the same axis, and the output shaft is connected to the differential mechanism inside the front axle case. This requires the front wheel transmission to have a relatively special structure, and if a large front wheel transmission is connected to the front axle case, the rolling range of the front axle case is inevitably narrow. turn into. On the other hand, according to the structure of the present invention, the input shaft and the output shaft are not on the same axis, that is, the input shaft and the output shaft are arranged in parallel, and a gear transmission structure or hydraulic clutch is used between the two shafts. The front wheel transmission device may be configured with a standard transmission structure using a vehicle, etc., and the output shaft may be connected to the input shaft of the differential mechanism in the front axle case.

〔Effect of the invention〕

Therefore, the weight balance of the aircraft can be made favorable for four-wheel drive vehicles, the performance of the front wheel transmission can be fully demonstrated during turns, and the front wheel transmission does not need to be of a special type. The cost increase can be suppressed by using a standard model that can be manufactured at low cost, and it does not interfere with the rolling structure of the front axle case.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS A four-wheel drive agricultural tractor, which is one embodiment of the present invention, will be described below with reference to the drawings.

As shown in Fig. 2, an engine (4), a main clutch ( 5) A transmission (6) and a control unit (7) are mounted on the rear of the aircraft, and a lift arm (8) connects various work devices such as a rotary tiller to the rear of the aircraft so that they can be raised and lowered, and power is transmitted to the work devices. A four-wheel drive agricultural tractor is configured with a PTO shaft (9).

Next, talking about the power transmission system of agricultural tractors, as shown in the figure, the power from the engine (4) is transmitted from the main clutch (5) to the main transmission and the sub-transmission (not shown below).
The power is sent to the transmission (6), which is composed of The transmission is transmitted to the front wheel transmission (10), the gear is changed, and the transmission is transmitted to the front wheels (1).

Next, the front wheel transmission (lO) will be explained in detail.
As shown in the drawings and FIG. 2, an input shaft (12) connected to the front output power shaft (15) is supported in the upper part of the front wheel transmission (10), and the lower part of the input shaft (12) An output shaft (13) is supported by. And the input shaft (12)
The first and second human power gears (14), (1
6) meshes with the first and second output gears (17) and (1B) which are freely rotatably fitted on the output shaft (13), and the output shaft (13) has a meshing part. Element(
19) is slidably attached with a spline structure, and the front wheel transmission (10) having the above structure is connected and fixed to the body frame (3) on the rear side of the front axle case (11).

Furthermore, the front axle case (11) is attached to the bracket 7) (20
) and the front wheel transmission (10), the front and rear axis of the aircraft (p
+), and is supported in a rolling manner around the input shaft (
22) and the output shaft (13) in the front wheel transmission (10)
are connected.

The shift member (1) in the front wheel transmission (10)
9) and the steering handle (23) are mechanically interlocked, and in the straight-ahead state, the shift member (19) is engaged with the first output gear (17), and in this state, the front wheel (1)
A standard drive state is established in which the rear wheels (2) are driven at substantially the same speed. Conversely, when the steering handle (23) is operated beyond the set angle, the shift member (19) is slid and engaged with the second output gear (1st), and in this state, the front wheels (1) are shifted backwards. This results in an increased speed driving state in which the speed is increased more than that of wheel (2).

[Another example]

In the above embodiment, the input shaft (12) and the output shaft (13) in the front wheel transmission (10) are arranged vertically, but a structure in which they are arranged laterally can also be adopted. Further, instead of having a structure in which the front wheel transmission (10) also serves as one bracket of the front axle case (11), a structure may be adopted in which the front axle case (11) is supported in a rolling manner by a 2&ll bracket.

Incidentally, although reference numerals are written in the claims section for convenient comparison with the drawings, the present invention is not limited to the structure shown in the accompanying drawings.

[Brief explanation of the drawing]

The drawings show an embodiment of a four-wheel drive type work vehicle according to the present invention,
Figure 1 is a sectional view of the front wheel transmission and its installation.
FIG. 2 is an overall side view of the agricultural tractor. (1)...Front wheel, (2)...Rear wheel, (
6)...Transmission, (10)...
...Front wheel transmission, (11) ...Front axle case.

Claims (1)

[Claims] The front wheels (1) transmit power from the transmission (6) installed at the rear of the aircraft to the freely steerable front wheels (1).
A front wheel transmission (10) that switches between a standard drive state in which the drive speeds of the rear wheels (2) and the rear wheels (2) are substantially equal, and an increased speed drive state in which the drive speeds of the front wheels (1) are greater than the rear wheels (2). A four-wheel drive working vehicle is provided with a front wheel transmission (10) connected and fixed to a body fixing part at the rear of a front axle case (11) at the front of the body.