JP3584491B2 - Turning control device for four-wheel drive vehicle - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to a turning control device for a four-wheel drive vehicle, and more particularly, to a four-wheel drive system that detects a steering angle to increase the speed of a front wheel, brake a rear wheel inside a turn, and raise a work machine. The present invention relates to a turning control device for a driving vehicle.
[0002]
[Prior art]
Conventionally, a pair of brake devices that can operate independently on the left and right are provided on the rear wheels of a four-wheel drive vehicle such as a tractor, and when turning the aircraft during tilling work, depress only one brake pedal. To control the rear wheels inside the turn to reduce the turning radius of the aircraft.
[0003]
Further, a device is provided for increasing the rotation speed of the front wheels to approximately twice that of the rear wheels, and when turning the body during tilling work, the rotation speed of the front wheels is increased to reduce the turning time. Further, an elevating switch for raising a working machine such as a rotary to the highest position is provided, and when turning the machine body during tilling work, the working machine is raised to the highest position so as not to be dragged.
[0004]
[Problems to be solved by the invention]
In the conventional four-wheel drive vehicle, when turning the body at the time of tilling work, the lifting operation of the work machine, the depression operation of one of the brake pedals, the speed-up operation of the front wheels, and the steering operation must be performed simultaneously. The operation is complicated.
There is also known a four-wheel drive vehicle that detects a steering angle of a steering wheel, determines that the aircraft is in a turning state, and automatically performs a speed increasing operation of a front wheel and a rear wheel braking inside the turning. If the lifting operation of the work machine is delayed, the cut-up point of the work machine remains largely inclined, and it becomes difficult to finish the headland.
[0005]
Therefore, while improving the turning performance of the four-wheel drive vehicle during the tilling operation, the turning operation is simplified, and a technical problem to be solved to prevent the roughening of the field arises. The purpose is to solve the problem.
[0006]
[Means for Solving the Problems]
The present invention has been proposed to achieve the above object, and in the invention of claim 1, means for detecting the steering angle of the steering, means for increasing the rotational speed of the front wheel during turning, and work during turning. In a four-wheel drive vehicle equipped with means for raising the machine, when the steering angle becomes equal to or greater than a set value, first, the means for raising the work machine is operated, and then the rotation speed of the front wheels is reduced. A turning control device for a four-wheel drive vehicle, comprising a control unit for determining whether or not to activate the speed increasing means based on the ascending output of the work implement.
According to a second aspect of the present invention, there is provided a four-wheel drive vehicle comprising: means for detecting a steering angle of a steering wheel; means for braking a rear wheel inside a turn when turning; and means for raising a work implement when turning. When the steering angle is equal to or greater than the set value, first, the means for raising the work machine is operated, and then whether or not the means for braking the rear wheel inside the turning is operated is determined by raising or lowering the work machine. It is an object of the present invention to provide a turning control device for a four-wheel drive vehicle, which is provided with a control unit that determines based on an output .
[0007]
[Action]
In the control means of the present invention, the steering angle of the steering is detected, and when the steering angle exceeds a set value, it is determined that the aircraft has turned. In such a case, first, the means for raising the work machine is operated to automatically raise the work machine. After the working machine is increased, the means for increasing the rotation speed of the front wheels, or determines Luke not actuate the means for braking the rear wheel inside. When the means for increasing the rotational speed of the front wheels or the means for braking the rear wheels inside the turning is operated , the turning time of the body is reduced and the turning radius is reduced.
[0008]
【Example】
Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram of a control system in a tractor as an example of a four-wheel drive vehicle, in which a tillage depth of a rotary is set with a tillage depth adjustment dial provided on an input side of a control unit, and a tillage position adjustment dial is used. Set the highest position of the work equipment. Then, the height of the working machine is detected by the lift arm sensor, and the tillage amount of the rotary is detected by the rear cover sensor.
[0009]
In addition, a steering angle sensor is provided as a means for detecting the steering angle of the steering, and an automatic brake switch is provided for turning on / off a means for braking the rear wheel inside the turn at the time of turning. Further, a check switch for shifting from the normal control mode to the check mode is provided, and the work implement is raised to the highest position or lowered to the position set by the position lever. Provide a lifting switch.
[0010]
On the output side of the control unit, a solenoid for raising the working machine and a solenoid for lowering the working machine are provided. A solenoid for right brake and a solenoid for left brake are provided as means for independently braking the rear wheel inside the turn when the auto brake switch is on, and the rotational speed of the front wheel is increased during the turn. A double speed device is provided as a means, and a double speed solenoid for turning on and off the double speed device is provided.
[0011]
A switch that is opened and closed according to a value detected by a high-speed sensor is connected to the solenoid for left and right brakes and the solenoid for double speed, and means for braking the rear wheel inside the turning when the body is running at high speed. Means for increasing the rotational speed of the front wheels during turning are not operated.
FIG. 2 is a flowchart of the entire control. First, the detection values of the respective sensors are read (step 101). When both the check switch and the elevating switch are on and immediately after the power is turned on (step 102). 103), the current sensor values are recorded in the EEPROM as respective reference values (step 104). In the check mode, the steering wheel is set to the neutral position in the left and right direction (straight running state) and recorded as a reference value of the steering angle sensor.
[0012]
On the other hand, if either or both switches are off at step 102 and if not immediately after power-on at step 103, sensor processing (step 105), position control or depth control (step 106), front wheel After performing the speed increase control (step 107), the automatic brake control (step 108), and the automatic lift control (step 109), the process returns to step 101.
[0013]
3 to 6 are flowcharts of each subroutine. First, in a position control or depth control routine, a lift arm target value and a detection value of a lift arm sensor are compared, and a lift of a work implement is raised in accordance with a deviation. Control is performed so as to output an ascending signal to the solenoid of the above, or to output a descending signal to a solenoid for lowering the work implement, or not to output a signal when the deviation is in the dead zone. When the UP mode is set in the automatic lift control routine to be described later, the set value of the raising position adjustment dial is set to the lift arm target value, and a lifting signal is output to the solenoid for lifting the work implement. Raise the work implement to the highest position.
[0014]
Next, the front wheel speed increasing control and the automatic brake control will be described. Both routines are executed only when the work implement lift flag is set to 1 in an automatic lift control routine described later. In the front wheel speed-up control, when the work implement lift flag is set to 1 and the detection value of the steering angle sensor exceeds a set value, the double speed solenoid is turned on to operate the speed doubler. Then, the rotation speed of the front wheels is increased to approximately twice that of the rear wheels.
[0015]
On the other hand, in the automatic brake control, when the work implement lift flag is set to 1 and the detected value of the steering angle sensor becomes equal to or more than the set value within a certain time during which the work implement rise timer is counting. Then, one of the left and right brake solenoids is turned on, and the rear inside wheel is braked. When the work implement ascent timer finishes counting, the left and right brake solenoids are turned off, and the one-side braking of the rear wheels is not performed.
[0016]
Further, the auto lift control will be described. First, when the auto brake switch is turned on (step 201) and a signal is input from the rear cover sensor (step 202), the process proceeds to the next step. This is such that this control is operated only during the rotary work, and the turning control including the auto-lift control is not operated during other work such as fertilizer application.
[0017]
Next, when the detected value of the steering angle sensor deviates from the straight traveling state, not immediately after the work implement raising operation has been performed (step 203), and after the work implement descent timer has finished counting (step 204). (Step 205), the UP mode is set (step 206). This is because the UP mode is not set immediately after the work implement raising operation is performed, and in the above-described position control, the setting value of the raising position adjustment dial is not set to the lift arm target value, thereby avoiding the maximum lifting of the work equipment. I do.
[0018]
Also, immediately after the work implement lowering operation described later is performed, the work implement lowering timer is started (steps 208 → 209). When the count of the work implement lowering timer does not end, that is, after the work implement is lowered and grounded The UP mode is not set within a certain period of time, so that even if an inexperienced operator meanders the machine after turning, the work machine does not rise again.
[0019]
Then, in step 207, the work implement rise timer is started, and the work implement rise flag is set to 1. Next, if the work implement lowering operation has just been performed, the process proceeds from step 208 to step 209 to start the work implement lowering timer, clear the work implement rise timer, and further return the work implement rise flag to 0. In addition, even if it is not immediately after the work implement lowering operation is performed, when the detection value of the steering angle sensor returns to the straight traveling state, the process returns from step 210 to step 209.
[0020]
This is because when the work implement is descending or when the steering angle of the steering is once returned to the straight running state, the work implement elevation flag is returned to 0 so that the front wheel acceleration control and the auto brake control are not operated. Things. That is, when the turning is completed, the steering operation is performed while lowering the work implement. However, even if an inexperienced operator excessively operates the steering, the automatic brake control is not operated.
[0021]
Thus, when the tractor performing the rotary operation performs the turning control, the automatic ascent of the work implement or the ascent operation by the operator is given top priority, and then the front wheel speed-up control and the automatic brake control are performed. .
Here, a steering angle sensor that detects the steering angle of the steering will be described. FIG. 7 shows the inside of the steering column 11. A screw 13 having a coarse pitch is provided at an intermediate portion of the steering shaft 12, and a boss 14 is screwed to the screw 13. A pin 15 protrudes from the outer surface of the boss 14, and the pin 15 is engaged with a slide groove 16 formed on the back side (driver's seat side) of the steering column 11. Further, a steering angle sensor 17 is connected to the tip of the pin 15.
[0022]
When the steering shaft 18 is rotated by steering the steering wheel 18, the boss 14 engaged with the screw portion 13 moves up and down, and the pin 15 protruding from the boss 14 is inserted into the slide groove. 16 up and down.
FIGS. 8 and 9 show the steering angle sensor 17. A bracket 19 is fixedly mounted near the slide groove 16 of the steering column 11, and the bracket 19 is screwed to the steering angle sensor 17. The steering angle sensor 17 uses a rotary potentiometer, and is mounted so that the sensor shaft 20 projects toward the driver's seat. Then, one end of the detection arm 21 is fixed to the sensor shaft 20, a locking groove 21 a is opened in the other end of the detection arm 21, and the pin 15 protruding from the slide groove 16 is fixed to the locking groove. 21a. Further, the steering angle sensor 17 is set so that the steering column 11 and the detection arm 21 are orthogonal to each other when the steering wheel 18 is in the neutral position and the body is in the straight traveling state.
[0023]
Thus, if the steering wheel 18 is steered to the left or right, the pin 15 moves up and down along the slide groove 16, and the detection arm 21 rotates to change the detection value of the steering angle sensor 17. The control unit calculates the steering angle of the steering based on the detection value of the steering angle sensor 17. At this time, the pin 15 moves up and down at an equal rate in proportion to the steering amount of the steering wheel 18, but the rotation angle of the detection arm 21 when the steering wheel 18 is close to the neutral position even with the same steering amount. Is big. That is, the resolution of the steering angle sensor 17 becomes high when the steering angle of the steering is near the neutral position, and a minute change in the steering angle can be finely detected.
[0024]
In this embodiment, a rotary potentiometer is used for the steering angle sensor 17, but the present invention is not limited to this. Although illustration is omitted, for example, a linear operation type potentiometer may be attached in the axial direction of the steering column 11. In such a case, since the sensor arm moves linearly in parallel with the steering column 11, the detection unit can be made compact.
[0025]
Therefore, the present invention can be variously modified without departing from the spirit of the present invention, and it is natural that the present invention extends to the modified ones.
[0026]
【The invention's effect】
As described in detail in the above embodiment, in the turning control of the four-wheel drive vehicle, the work implement is first raised, then the front wheels are accelerated and the inside rear wheel braking is performed. The problem that the work machine is dragged at the start or that the rounded-up portion of the work machine remains largely inclined is eliminated.
[0027]
In this manner, the unevenness of the swirled portion is reduced, and the finishing of the headland portion is facilitated, which can contribute to the improvement of workability.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a control system according to an embodiment of the present invention.
FIG. 2 is a flowchart of the entire control.
FIG. 3 is a flowchart of position control or depth control.
FIG. 4 is a flowchart of front wheel speed increase control.
FIG. 5 is a flowchart of an automatic brake control.
FIG. 6 is a flowchart of an automatic lift control.
FIG. 7 is a partially cutaway side view showing the inside of the steering column.
FIG. 8 is a rear view of a main part of the steering column showing a mounting state of the steering angle sensor.
FIG. 9 is a side view of a main part of the steering column showing a mounting state of the steering angle sensor.
[Explanation of symbols]
11 Steering column 12 Steering shaft 14 Boss 15 Pin 17 Steering angle sensor

Claims (2)

In a four-wheel drive vehicle including a means for detecting a steering angle of steering, a means for increasing a rotation speed of a front wheel when turning, and a means for raising a work implement when turning, the steering angle is set to a predetermined value. When this is the case, the control unit that first activates the means for raising the work implement, and then determines whether to activate the means for increasing the rotation speed of the front wheel based on the output of the work implement, A turning control device for a four-wheel drive vehicle, wherein the turning control device is provided. In a four-wheel drive vehicle provided with a means for detecting a steering angle of a steering, a means for braking a rear wheel inside a turn during turning, and a means for raising a work implement during a turn, the steering angle is set to a predetermined value. When this is the case, first, the control unit that operates the means for raising the work machine, and then determines whether to activate the means for braking the rear wheel inside the turn based on the output of the work machine , A turning control device for a four-wheel drive vehicle, wherein the turning control device is provided.

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