JP3245413B2 - Travel drive control device for tractor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[Industrial applications]

The present invention relates to a traveling drive control device for a tractor, in which a driving mode of a wheel is selected by a simple operation according to working conditions, traveling conditions, and the like.

[0002]

2. Related Art and Problems to be Solved by the Invention

Conventionally, tractor traveling driving modes include a four-wheel constant-speed driving mode in which the peripheral speed of the front wheels is substantially equal to the peripheral speed of the rear wheels, a two-wheel drive mode in which the front wheels do not drive the rear wheels, and The configuration is such that the mode can be switched to a front wheel speed-up driving mode in which the peripheral speed of the wheel is set to substantially double the peripheral speed of the rear wheel and driven. As disclosed in Japanese Utility Model Laid-Open Publication No. 63-202523, there is known an apparatus that switches from the four-wheel constant-speed drive mode to the front-wheel speed-up drive mode when turning in a field.

However, in the field work using a tractor, it is necessary to appropriately and appropriately switch the front wheel drive mode at the time of turning due to the slip state and the weight balance between the front and rear of the vehicle. Then, there is a problem that a quick turning operation, for example, a lifting operation or a brake operation of the working machine is delayed, or an erroneous operation is likely to occur.

[0004]

[Means for Solving the Problems]

In view of the above problems, the present invention provides a two-wheel drive state with the rear wheel 2 by turning off the power transmission of the front wheel 1, a standard four-wheel drive state in which the front wheel 1 is driven at substantially the same speed as the rear wheel 2, or a front wheel drive state. It is provided with clutches 19 and 25 for switching to a front wheel speed-up four-wheel drive state in which the wheel 1 is driven at a speed higher than that of the rear wheel 2 and, when the tractor turns, turns from the standard four-wheel drive state to the two-wheel drive state, or A traveling drive control device for a tractor including a switching tool 3 for selecting whether to turn from the standard four-wheel drive state to the front wheel speed-up four-wheel drive state.

[0005]

【The invention's effect】

When performing straight-ahead work with the tractor, the vehicle travels in a standard four-wheel drive state in which the peripheral speeds of the front wheel 1 and the rear wheel 2 are substantially the same, and when turning at a field end or the like, the switching tool 3 is operated. Whether to turn in a set driving state, that is, in a two-wheel drive state with the rear wheels 2 with the front wheel 1 turned off, or to turn in a front wheel speed-up four-wheel drive state in which the front wheels 1 are accelerated with respect to the rear wheels 2 Can be easily selected even when the working state changes and the driving state needs to be switched as described above.

[0006]

【Example】

Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIGS. 1 and 4, the tractor has an engine 5 mounted on a front portion of a vehicle body 4 and front wheels steered by a steering wheel 6 on the left and right sides of the engine 5.
1, 1 are mounted on the rear, and a cockpit 7 and rear wheels 2, 2 are mounted on the rear of the vehicle body to drive the front wheel 1 or the rear wheel 2 through the transmission device by using the rotational power of the engine 5. It is configured to run.

A main clutch 9 is provided in a clutch housing 8 connected to a rear portion of the engine 5.
A rear transmission case 11 from the main clutch 9 via a transmission shaft 10
Is transmitted to the transmission 12. From inside the rear transmission case 11, the power take-out shaft 13 projects to the rear to transmit a working device connected to the rear of the vehicle body. Further, the rear wheel differential device 15 is interlocked with the transmission 12 via the traveling shaft 14 and is connected to the rear wheel differential device 15.
From 15, a rear wheel axle 17 having rear wheels 2 is transmitted via left and right rear axles 16. Reference numeral 18 in the drawing denotes a rear wheel brake for braking the rear axle 16.

Further, the transmission 12 includes a precursor clutch 19 and a front drive shaft 20.
, And the front wheel differential 21 further transmits a front wheel axle 23 having the front wheel 1 and the like via left and right front wheel axles 22 and the like. On the front wheels 22, a front wheel brake 24 for braking the rotation of the front axle 22, a front wheel clutch 25 for turning on and off the transmission from the front axle 22 to the front wheel axle 23 are provided.

Each rear wheel brake 18, precursor clutch 19, each front wheel brake
24, and each front wheel clutch 25, etc. are operated by hydraulic pressure, and a controller CPU having a microcomputer
In response to an output command from the controller, the solenoid valves 26, 27, 28, 29, etc. are operated by switching operations.
In addition, the steering shaft 6 is provided with the steering angle,
That is, the steering angle sensor 30 for detecting the steering direction is provided, and when the detection angle becomes larger than a predetermined value, the drive of the front wheel 1 is turned off and the two-wheel drive turning by the rear wheel 2 or It is configured to switch between four-wheel drive turning in which the peripheral speed of the front wheel 1 is increased from the peripheral speed of the rear wheel 2 and driven.

A drive mode switch 3 which is a switching tool for selectively setting the turning mode is provided, for example, on a dashboard 32 near the steering handle 6, and is pressed by a fingertip into four modes A, B, C, and D. The switch can be switched in stages, and this switching is repeated in a rotary form. That is, every time the switch 3 is depressed, the "two-wheel drive mode A" by the rear wheel 2 at all times, the "four-wheel drive mode B" by the front and rear wheels at all times, and the front wheel 1
"Super full turn mode C" in which the peripheral speed of the front wheel 1 is increased to the peripheral speed of the rear wheel 2, and "Two-wheel drive mode D" in which the driving of the front wheel 1 is switched from the four-wheel drive state only during turning. It can be switched. Each mode A to D selected by the drive mode switch 3
As a digital display or a lit display on a display unit provided in a part of the dashboard 32, a time delay device or a delay timer is provided so as to output to the solenoid valves 26 to 29 corresponding to each mode immediately after this display. It is good to provide. In this case, when the selected mode is incorrect, the driver can press the drive mode switch 3 again to select the desired mode after checking the display and confirming that the output section is not operated.

Next, a transmission configuration for each drive mode will be described. When the drive mode switch 3 is in the "four wheel drive mode B", the clutch 19 is engaged and the left and right front wheel clutches 29 are engaged. Therefore, the rotational power output from the transmission 12 is transmitted to the traveling shaft 14, the rear wheel differential 15, the left and right rear axles 16, and the rear axle 12 in this order, and the transmission
The rotational power output from 12 is sequentially transmitted to the precursor clutch 19, the front axle 20, the front wheel differential 21, the left and right front axles 22, and the front wheel clutch 25, and the front wheel 1 is transmitted. Therefore, the tractor travels in the standard four-wheel drive state with the front wheels 1 and the rear wheels 2.

When the drive mode switch 3 is in the “two-wheel drive mode A”, the clutch 19 is disengaged by energizing the solenoid valve 27, and the front wheel clutch 25 is disengaged by energizing the left and right solenoid valves 29. Become. Therefore, the rotational power output from the transmission 12 is sequentially transmitted to the traveling shaft 14, the rear wheel differential 15, the left and right rear axles 16, the rear axle 2 is transmitted, and the front wheels 1 are not driven. I have. Therefore, the tractor travels in a two-wheel drive state with the rear wheels 2.

When the drive mode switch 3 is in the “super full turn mode C”, the tractor is normally in the “four wheel drive mode B”, and the detection value of the steering angle sensor 30 indicates a predetermined steering angle. Upon detection, for example, when the vehicle is turning leftward, power is supplied to the solenoid valve 29 on the right side, the front right wheel clutch 25 is disengaged, and the solenoid valve on the right side
The right front wheel brake 24 is activated by the energization of 28, whereby the peripheral speed of the front wheel 1 on the left turning side is driven by the differential of the front wheel operating device 21 at twice the traveling speed, while the front speed on the right side is increased. The wheel 1 is in a free rotation state. The same applies to the right turn, and when these turns are completed, the state returns to the standard four-wheel drive state.

When the drive mode switch 3 is set to “two-wheel drive mode D”
When the detection value of the steering angle sensor 30 detects a predetermined steering angle, the clutch 19 is disengaged, and the left and right front wheel clutches 25 are disengaged. Is switched to the two-wheel drive state. In this case, when the turning is completed, the precursor clutch 19 and the left and right front wheel clutches 25 are engaged and return to the standard four-wheel drive state.

In the “super full turn mode C” and the “two-wheel turn mode D”, the rear wheel brake 18 inside the turn may be operated by the output of the solenoid valve 26 in conjunction with the turn operation. good. In the "two-wheel drive mode D", the power transmission may be interrupted by disengaging the left and right front wheel clutches 29 with the precursor clutch 19 engaged.

When performing straight-ahead work with the tractor configured as described above, the vehicle travels in a four-wheel drive mode in which the peripheral speeds of the front wheel 1 and the rear wheel 2 are substantially the same. By operating the switch 3, the front wheel drive mode set in advance, that is, the driving of the front wheel 1 is turned off to perform “two-wheel turn” by the rear wheel 2, or the peripheral speed of the front wheel 1 is Since it is possible to select either “super full turn” to increase the speed relative to the peripheral speed, it is possible to easily operate even when the working state changes and the driving state needs to be appropriately switched. .

[Brief description of the drawings]

FIG. 1 is a plan view showing a transmission mechanism of a tractor.

FIG. 2 is a control block diagram

FIG. 3 is a flowchart.

FIG. 4 is an overall side view of the tractor.

[Explanation of symbols]

 1 Front wheel 2 Rear wheel 3 Drive mode switch

Claims (1)

(57) [Claims] 1. A two-wheel drive state by the rear wheel 2 with the power transmission of the front wheel 1 turned off, a standard four-wheel drive state in which the front wheel 1 is driven at substantially the same speed as the rear wheel 2, or a front wheel 1 19,25 clutch that switches to the front wheel speed-up four-wheel drive state, which also drives with increased speed
And a switching tool 3 for selecting whether to turn from the standard four-wheel drive state as a two-wheel drive state or from the standard four-wheel drive state to a front wheel speed-up four-wheel drive state when turning the tractor. Travel drive control device.