JPH01164626A - Front-wheel-drive control device in four-wheel-drive power vehicle - Google Patents

Abstract

PURPOSE:To improve safety preventing unprepared switching to a high speed side by switching a high and low speed selector device, provided in a front wheel driving system, to a low speed side when right and left brake pedals corresponding to independent right and left brake devices are connected. CONSTITUTION:Power of an engine 2, after it is decelerated in each main and subtransmissions 7, 8 in a transmission case 4, is transmitted to right and left rear wheels 6 via a rear wheel differential gear 9 and a final reduction gear 10. While the power of the engine 2 is transmitted from a high and low speed selector device 18, provided in the bottom position of a front wheel transmitting shaft 14 associated with each transmission 7, 8, to right and left front wheels 5 via a propeller shaft 19, front wheel differential gear 20 and a final reduction gear 21. In this constitution, each low and high speed use hydraulic clutch 22, 23 is additionally provided respectively in the high and low speed selector device 18. When right and left brake pedals 12 are connected and locked, the low speed use hydraulic clutch 22 is connected, and the right and left front wheels 5 are rotated in a low speed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a front wheel drive control device for a four-wheel drive power vehicle such as a tractor.

[Prior Art] While four-wheel drive power vehicles have excellent running stability when traveling on rough terrain such as muddy roads or farm fields, they tend to have a large turning radius. For this reason, a high/low speed switching device is installed in the front wheel drive system, which rotates the front wheels at a relatively high speed only when turning in conjunction with the turning operation, and when driving straight, the high/low speed switching device is switched to the low speed side to return to normal working speed. The control device that allows it to travel at the appropriate speed is cursed.

[Problems to be Solved by the Invention] However, in a power vehicle equipped with such a high/low speed switching device, when the turning angle of the steering wheel exceeds a predetermined angle, the high/low speed switching device is switched to the high speed side. Although conventional devices are equipped with a mechanism to manually release such interlocking for safety reasons,
If you forget to release the button, if you accidentally turn the steering wheel too far while driving on a public road at high speed, the high/low speed switching device will switch to the high speed side, creating a dangerous situation where the pilot is likely to be thrown off the aircraft. was there.

[Means for solving the problems] This invention is proposed in view of the above drawbacks, and includes:
To provide a front wheel drive control device for a power vehicle that is highly safe by activating a high/low speed switching device when working in a field and disabling it when traveling at high speed on the road or the like.

For this reason, the following technical measures were taken.

That is, in a four-wheel drive power vehicle which is provided with independent left and right brake devices 11.11 and is equipped with a high-low speed switching device 18 in the front wheel drive system, the brake device 11.1
A configuration of a front wheel drive control device for a four-wheel drive vehicle, characterized in that a switching means is provided for switching a high/low speed switching device 18 to a low speed side when a pair of operating pedals 12. do.

[Examples and effects] Hereinafter, the present invention will be described in detail based on the drawings.

First, let me explain the configuration: 1 is a tractor.

It has an engine 2, a clutch housing 3, a transmission case 4, etc., and a front axle 5.5 for running and rear wheels 6, 6 are provided at the front and rear of the body. Inside the mission case 4, there is provided a main transmission 7 with at least three forward speeds and one reverse speed, and a sub-transmission 8 with two high and low speeds. The rotational power of the engine 2 is decelerated through the main and auxiliary transmissions 7.8, and transmitted to the rear wheels 6.6 via the rear wheel differential 9 and the final reduction gear 10. Reference numeral 11.11 is a brake device, and the left and right brake pedals 12.12 can be operated independently or simultaneously by a pair of left and right brake pedals 12.12 pivotally supported near the right side step of the aircraft body. 1) A transmission shaft 14 of the front wheel transmission system 13 that is linked to the transmission 7.8 is provided in the lower abdomen of the mission case 4, and two large and small gears 16 and 17 are fixed to this transmission shaft 14. There is. Further, a high/low speed switching device 18 is provided below the transmission shaft 14, and the high/low speed switching device 18 is linked to a front wheel differential device 20 in the front axle case via a propulsion shaft 19. from each front axle 5.5 via the final reduction gear 21
to drive. The high/low speed switching device v113 has a low speed hydraulic clutch 22 and a high speed hydraulic clutch 23, and when the low speed clutch 22 is connected, the front If! ! The peripheral speed of 5.5 is the rear wheel 6.
The circumferential speed of the front wheels 5.5 is about 1.055 times higher than that of the front wheels 5.5, and when the high-speed hydraulic clutch 23 is connected, the circumferential speed of the front wheels 5.5 is about twice as high as that of the low-speed wheels. FIG. 3 shows a control system, 27 is a hydraulic pump, 28 is the hydraulic clutch 2.
Solenoid 29.30 with a solenoid valve that switches 2.23
and is controlled by a control circuit 31. Reference numeral 32 denotes a rotation detector which detects when the pitman arm 34, which rotates by operating the steering handle 33, is rotated by a predetermined angle or more, and is composed of an on/off switch. 35 is the left and right brake pedal 12.12
When the lock plate 36 provided on the left brake pedal 12 engages with the receiving part of the right brake pedal 12 and both pedals 12.12 are interlocked, this switch 35 is activated. It is turned on and the low speed side solenoid 29 is excited. When the switch 35 is in the on state, only the low-speed hydraulic clutch 22 is always operated according to instructions from the control circuit 31.

Therefore, even if the steering handle 33 is rotated significantly, the high-speed hydraulic clutch 23 will not be connected.
40 is a switch that keeps the solenoid valve 28 neutral,
When this is turned on, the solenoid valve 28 becomes neutral according to a command from the control circuit 31, and the state is switched to rear wheel drive.

Next, the effect will be explained. When a working machine such as a rotary tiller is connected to the rear of the tractor 1 and the tractor 1 is traveling in a field, the left and right brake pedals 12, 12 are operated independently, so only the low-speed hydraulic clutch 22 is activated and the front wheels 5, 12 are operated.
5 rotates at a circumferential speed approximately 1°055 times that of the rear wheel 6.6. When turning at the edge of the field, the steering handle 33 is turned significantly. In this case, when the pitman arm 34 turns more than a predetermined angle, the turning detector 32 detects this state and turns on the switch, which activates the high-speed hydraulic pressure. Connect the clutch 23 and turn the aircraft with the circumferential speed of the V5.5 raised to about twice that at low speed, and the front wheels 5.5 will become the resistance of the rear wheels 6.6. Because there is no brake pedal, it is possible to turn in a small radius.At this time, one brake pedal
If you press 2, you can make even smaller turns. When the steering wheel 33 is returned to its original position after turning, the low-speed hydraulic clutch 22 is connected, and the front wheels 5.5 rotate at a low speed.

On the other hand, when leaving the field and driving on the road after finishing work, it is necessary to lock the left and right brake pedals 12 and 12 to prevent the machine from rolling over due to sudden turns. When the pedal 12.12 is connected by the locking plate 36, the switch 35
is turned on, and as a result, the low-speed hydraulic clutch 22 is connected and the front wheels 5.5 are driven to rotate at a low speed.

Moreover, this switch 35 is connected to the left and right brake pedals 12.
．． As long as 12 is connected, it remains on, so the high-speed hydraulic clutch 23 will not be connected even when the aircraft turns, making it safe.

[Effects of the Invention] Since the present invention is configured as described above, it has the following technical effects. That is, when driving on the road etc., the left and right brake pedals 12.12 must be connected, but simply by adding the familiar operation of connecting the pedals 12.12, the high/low speed switching device 18 is always set to the low speed side. It will be switched.

Even if the steering wheel 33 is turned significantly while driving in four-wheel drive mode, the high/low speed switching device 18 will not be switched to the high speed side, improving safety.

[Brief explanation of the drawing]

The drawings show an embodiment of the invention, with FIG. 1 being a side view, FIG. 2 being a power transmission diagram, and FIG. 3 being a control circuit diagram. Explanation of symbols 1 Tractor 12 Brake pedal 18 High/low speed switching device 22 Low speed hydraulic clutch 23 High speed hydraulic clutch

Claims (1)

[Claims] In a four-wheel drive power vehicle which is provided with left and right independent brake devices 11, 11 and is equipped with a high/low speed switching device 18 in the front wheel drive system, a pair of operating pedals 12, 12 for operating the brake devices 11, 11 are provided. A front wheel drive control device for a four-wheel drive vehicle, characterized in that a switching means is provided for switching a high/low speed switching device 18 to a low speed side when connected.