JPH0688540B2 - Brake equipment for agricultural vehicles - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a brake device for agricultural work vehicles such as tractors and passenger rice transplanters. More specifically, when the steering angle of the front wheels exceeds a preset value, The present invention relates to a brake device for a four-wheel drive agricultural work vehicle equipped with a front wheel speed increasing device for increasing a rotation peripheral speed to be higher than a rotation peripheral speed of rear wheels.

[Conventional technology]

Conventionally, the left and right rear wheels are provided with independent manipulable brakes.

[Problems to be Solved by the Invention]

The four-wheel drive type agricultural work vehicle equipped with a front wheel speed increasing device has an advantage that it is possible to reduce a headland on a ridge because a small turn can be made by increasing the speed of the front wheel. It is known that a sharp turn from the agricultural work vehicle can be achieved by operating the front wheel speed increasing device and braking the rear wheel on the inner side in the turning direction. In such a case, in the agricultural work vehicle according to the above-mentioned conventional technique, the operator brakes the rear wheel on the inner side in the turning direction.However, depending on the soil condition of the running ground, for example, if braking is continued on a soft ground, the topsoil will be dragged. There may be a problem that the tires of the rear wheels to be braked slip and the vehicle cannot turn sharply as expected.

Therefore, it has been found that it is effective to intermittently brake the rear wheel on the inner side in the turning direction in order to prevent the above problems.
However, in the prior art in which the rear wheel is manually operated, that is, the operator performs the braking operation, the intermittent braking operation described above requires skill, so that no one can do it.

It is an object of the present invention to provide a brake device for an agricultural work vehicle that is capable of automatically performing the above-described intermittent braking operation to easily intermittently brake the rear wheel inside the turning direction regardless of who steers the vehicle. To do.

[Means for Solving the Problems]

In order to achieve the above-mentioned object, the present invention provides a brake device for an agricultural vehicle described above, which is provided with intermittent braking means for intermittently braking a braking mechanism for a rear wheel on the inner side in the turning direction in conjunction with steering operation of the front wheel. At the same time, the intermittent braking means is linked so as to be operable at the steering angle which is equal to or greater than the set value.

[Action]

According to the above configuration, the intermittent braking operation of the rear wheel on the inner side in the turning direction can be automatically performed by the intermittent braking means at the time of a sharp turn when the front wheel speed increasing device is operated.

〔The invention's effect〕

Therefore, since the rear wheel inside the turning direction can be intermittently braked automatically by operating the steering wheel, it is possible to easily perform the intermittent braking between the rear wheels inside the turning direction regardless of who steers the vehicle. became.

〔Example〕

FIG. 2 shows an overall side view of an agricultural tractor as an example of an agricultural vehicle equipped with a brake device according to the present invention.

As shown in FIG. 2, by operating the steering wheel (5), the aircraft (1) equipped with the engine (1), the front wheel differential mechanism (2), the rear part with the control section (3) and the mission case (4) can be operated. Driven front wheels (6) and rear driven wheels (7) that can be steered
It is configured to run on.

The mission case (4) includes a front wheel differential mechanism (2).
The transmission shaft (8) for driving the front wheels (6) is connected through the steering shaft, and the steering angle of the front wheels (6) driven by the transmission shaft (8) is as shown in FIG. , Switches (16), (16) that detect the rotation of the pitman arm (15) when the value exceeds the set value (for example, 40 °)
And, by the control device (S) that operates based on the detection of the switches (16) and (16), the front wheel speed-increasing that makes the rotational peripheral speed of the front wheel (6) faster than that of the rear wheel (7). (9) is decorated.

Next, the brake device will be described.

As shown in FIG. 1, an intermittent braking means (13) for intermittently braking a control mechanism (12) including a brake (10) for the left rear wheel and a brake (11) for the right rear wheel, and a front wheel. The braking device is composed of a detection mechanism (14) that detects that the steering angle of the steering wheel has exceeded a set amount.

The detection device (14) is provided with a switch (1) on both sides of the pitman arm (15) which is rotated by the handle (5).
7) and (17) are provided so that the switch (16 or 17) is activated when the pitman arm (15) rotates more than a set angle, and the set angle is set to that of the front wheel (6). The steering angle is configured to correspond to a set amount (for example, 45 °) of an angle equal to or larger than the set value.
Note that (20) is a drag link.

The intermittent braking means (13) includes hydraulic brakes (1
Connect a pulse signal and a pulse generation circuit (19) that generates a pulse current based on this pulse signal to a solenoid driven switching valve (18) that selectively switches pressure oil supply to 0) and (11). To do.

The pulse generation circuit (19) is connected to the detection mechanism (1
4), which allows the intermittent braking means (1
3) is linked so as to be operated by a steering turning operation of the set amount (45 °) or more.

Next, the operation of this brake device will be described.

Turn the steering wheel (5) to the right and turn to the right, and further turn the steering wheel (5) to the right. When the front wheel (6) is turned 40 ° to the right, the front wheel speed increasing device (9) operates. It becomes easy to make a sharp turn. When the steering angle of the front wheel (6) exceeds 45 ° by further steering to the right, the pitman arm (15) actuates the right switch (17), and the detection result is the pulse generation circuit (19). ) Is entered. This input signal operates so as to switch the switching valve (18) in the direction in which pressure oil is supplied to the brake (11) on the right rear wheel, but a pulse current is applied to the solenoid that drives the switching valve (18). Since it is input, the switching valve (18) repeatedly moves between the right open and neutral positions according to the frequency of the pulse signal, and as a result, the right rear wheel (7) is intermittently braked. is there.

Further, the pulse generation circuit (19) is provided with a selection switch (21) for disabling the operation of this circuit, and it is possible to select not to perform intermittent braking.

[Another embodiment]

A potentiometer is attached to the rotating shaft of the pitman arm (15), and the pulse signal of the pulse generation circuit (19) is made variable so that the braking time in intermittent braking becomes longer as the steering angle of the steering wheel increases. Alternatively, the potentiometer and the pulse generating circuit (19) may be linked together.

Further, the pulse signal of the preliminarily pulse generation circuit (19) may be artificially selected and operated.

It should be noted that reference numerals are added to the claims for convenience of comparison with the drawings, but the present invention is not limited to the structures of the accompanying drawings by the entry.

[Brief description of drawings]

1 is a circuit diagram and FIG. 2 is an overall side view of an agricultural tractor. (6) ... front wheel, (7) ... rear wheel, (9) ... speed increasing device, (12) ... braking mechanism, (13) ... intermittent braking means.

Claims (1)

[Claims] 1. A front wheel speed increasing device (9) for increasing the peripheral speed of rotation of the front wheel (6) when the steering angle of the front wheel (6) exceeds a set value. A brake device for a four-wheel drive type agricultural work vehicle equipped with the brake device, wherein the braking mechanism (12) for the rear wheel (7) inside the turning direction is intermittently braked in conjunction with the steering operation of the front wheel (6). A braking device for an agricultural vehicle in which a braking means (13) is provided, and the intermittent braking means (13) is operably linked with the steering angle which is equal to or more than the set value.