JP3719097B2 - Wheel steering device for towed work machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a wheel steering device for a work machine towed by a tractor, and more particularly to a wheel steering device suitable for preventing a flow of the work machine in a tilt direction in an inclined field.
[0002]
[Prior art]
Towing a towed work machine on a sloping ground, the operator operates the steering switch of the work machine and corrects the flow based on the intuition and experience that the work machine is swung in the direction of the farm field and deviates from the original trajectory. It was forced to perform work, which caused a decrease in work efficiency and fatigue of workers due to backward confirmation and machine operation.
[0003]
The devices that have made practical use of automatic steering operation so far have built-in limit switches etc. in the draw bar that is the connecting part of the towed work machine, and if the draw bar rotates at a certain angle (operating point) during turning, the tow When the steering wheel of the work implement is steered to the wheel steering angle limit point in the direction opposite to the direction of rotation of the drawbar, the drawbar rotates in the reverse direction when it goes straight from the turning state, and when it reaches a certain angle (operating point) again, it is pulled Control was performed to return the steering of the work implement to the neutral point. However, with such a method, it has been impossible to control the flow stop of an inclined land that requires precise steering control.
[0004]
In addition, even if the current working machine with an offset hitch mechanism has an analog sensor attached to the drawbar, if the neutral point of the drawbar is controlled as the neutral point of the work machine frame, it will be adjusted to match the straw on the field. There was a problem that the zero point of the sensor shifted every time. If this problem is solved by a physical method, for example, a method that does not change the absolute drawbar angle during straight towing even if the hitch angle is changed, or a method that adjusts the sensor each time the vehicle is brought together, the mechanism becomes complicated. This is not practical because it not only increases costs but also requires fine adjustments.
[0005]
[Problems to be solved by the invention]
The present invention has been made to solve the above-described problems, and the problem is that the hitch angle of the work implement changes when the work implement is pulled by a tractor on a sloping ground or when the work implement is fitted together. Or when turning the work implement by steering operation of the tractor, the work implement always maintains the positional relationship with the tractor offset by the hitch, and the tractor track and the work implement track are at a constant interval. An object of the present invention is to provide a wheel operation device that automatically controls a wheel steering angle of a work machine.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the means employed by the present invention includes a wheel steering device for a work machine, a hydraulic mechanism for steering the wheel of the work machine, a computer for controlling the hydraulic mechanism, and an intersection angle between the draw bar and the hitch. It consists of a drawbar sensor that detects the drawbar angle, a hitch sensor that detects the hitch angle between the hitch and the wheel axle of the work implement, and a wheel sensor that detects the actual steering angle of the work implement wheel. The detection signal of the hitch sensor is input to the computer to calculate the deviation angle of the work implement traveling direction relative to the tractor traveling direction, and the target rudder angle of the wheel is set from the deviation angle, and the actual rudder angle of the work implement wheel is the target. This is because the computer controls the hydraulic mechanism so that the steering angle is obtained.
[0007]
Here, if the hitch angle (clockwise) is θA and the drawbar angle (counterclockwise) is θB, θA = θB when the tractor traveling direction matches the traveling direction of the work implement, and the work implement moves in the traveling direction on a sloping ground. On the other hand, when the tractor is shifted to the right or the tractor turns to the left, θA> θB, and when the work implement is shifted to the left with respect to the traveling direction on the slope, or the tractor is turned to the right, θA <θB.
[0008]
Assuming that the deviation angle between the traveling direction of the tractor and the work implement is θC, θC = θA−θB. The steering angle with respect to the axle of the wheel for setting the deviation angle to θD is θD = θR−θC, where the neutral angle of the wheel is θR (normally a right angle). The computer controls the hydraulic mechanism such that the actual steering angle θE of the wheel sensor signal matches the target steering angle θD.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described based on the embodiment shown in FIG.
[0010]
FIG. 1 is a plan view of a tractor 1 and a work machine 2 that perform harvesting work on an inclined land. The tractor 1 travels perpendicular to the tilt direction indicated by the thick arrow. The working machine 2 that has been pulled at a drawbar angle of 120 degrees and a hitch angle of 120 degrees is swept in the tilt direction, and the drawbar angle is shifted 15 degrees in the traveling direction to 135 degrees.
[0011]
A draw bar sensor 5 is disposed at a connection portion between the draw bar 3 and the hitch 4 of the tractor 1, and a hitch sensor 6 is disposed at a connection portion between the hitch and the work implement 2. A wheel rudder angle sensor 9 is disposed at the mounting portion of one wheel 8 of the axle 7 of the work machine 2, and the wheel 8 is steered by a hydraulic cylinder 10 disposed in the work machine 2. A computer 11 for controlling the hydraulic cylinder 10 is disposed in the tractor 1, a draw bar sensor 5 outputs a signal of a draw bar angle θB that is an intersection angle between the draw bar 3 and the hitch 4, and the hitch sensor 6 indicates an axle 7 of the hitch and the work implement 2. The wheel sensor 9 inputs a signal of the actual steering angle θE of the wheel 8 with respect to the axle 7 to the computer 11. The computer 11 calculates the deviation angle θC of the work implement 2 with respect to the traveling direction of the tractor 1 based on these signals, sets the target rudder angle θD of the wheel 8 that corrects the deviation angle, and the actual rudder angle θE is the target. The hydraulic cylinder 10 is operated so that the steering angle θD is obtained.
[0012]
The control of the computer 11 is performed in the automatic steering mode as shown in the flowchart of FIG. If switching to OFF is not performed in the mode switching operation in step 1, the neutral angle θR with respect to the axle of the wheel is set in step 2, and the hitch angle θA, the drawbar angle θB, the actual steering of the wheel are set in steps 3, 4, and 5. The angle θE is input and averaged in step 6 for noise removal.
[0013]
Next, in step 7, the deviation angle θC of the work implement with respect to the tractor traveling direction is calculated from θC = θA−θB. In step 8, the target steering angle θD of the wheel is determined by θD = θR−θC. In S10, the difference S between the actual steering angle of the wheel and the target steering angle is calculated by S = θE−θD. In step 10, if S is within the dead zone, the process returns to step 1; In step 11, positive / negative is determined. If positive, a right steering signal is output to the hydraulic cylinder in step 12, and if negative, a left steering signal is output to the hydraulic cylinder in step 13. It is done. Next, the process returns to Step 1 and the process is repeated again. Therefore, the flow in the inclination direction of the work implement 2 is automatically corrected, and the drawbar angle returns to the initial 120 degrees, so the advance direction of the work implement is the advance of the tractor. Match the direction.
[0014]
【Example】
Next, turning and offset of the working machine provided with the embodiment will be described.
[0015]
FIG. 3 shows that the tractor 1 that makes a steady turn pulls the work implement 2 by offsetting it with a drawbar angle and hitch angle of 120 degrees, and the work implement 2 is shifted by 5 degrees with respect to the traveling direction of the tractor 1 and the tractor 1 and the work implement It is a top view which shows the state from which the space | interval of 2 advancing trajectory has become narrow.
[0016]
The computer 11 calculates the deviation angle θC = 5 degrees from the signals of the drawbar angle θB and the hitch angle θA of the drawbar sensor 5 and the hitch sensor 6, sets the target rudder angle θD of the wheel 8 to 85 degrees, and the hydraulic cylinder 10 To adjust the signal of the actual steering angle θE of the wheel sensor 9 to 85 degrees. As a result, the drawbar angle θB returns to 120 degrees again, the work implement 2 maintains the initially set offset position, and the travel trajectory interval between the tractor 1 and the work implement 2 becomes the original width.
[0017]
FIG. 4 is a plan view showing a state in which the tractor 1 and the work implement 2 travel through the field 13 and 14 having different ridge widths.
[0018]
In the field 13, when the work machine 2 is offset by a relatively large hitch angle θA and the tractor 1 that has been working enters the field 14 having a different ridge width, the work machine 2 is adjusted to a different ridge width from the previous one. In addition to changing the wheel widths of the tractor and the work implement, the hitch cylinder 12 is operated to slightly reduce the hitch angle θA, and the offset of the work implement 2 relative to the tractor 1 must be adjusted slightly. However, the computer 11 sets the target rudder angle of the wheel 8 by calculating the deviation angle of the traveling direction of the tractor 1 and the work implement 2 regardless of the change in the hitch angle and the drawbar angle by the hitch cylinder 12. The actual steering angle is controlled to coincide with the target steering angle. Therefore, even if the offset position of the work implement 2 is changed in order to enter a field having a different ridge width, there is no need to correct the sensor of the wheel steering device as in the conventional case.
[0019]
【The invention's effect】
As described above, the wheel steering device of the present invention is different from the conventional one in which the wheel is steered by the draw bar sensor that detects the draw bar angle between the draw bar and the hitch of the connecting portion with the tractor. The computer calculates the deviation angle between the tractor and the work implement in the traveling direction from the hitch sensor that detects the hitch angle between the work implement axle and the work implement axle, and sets the target steer angle of the work implement wheel. Since the steering hydraulic mechanism is controlled so that the target steering angle becomes the target steering angle, the following excellent effects are obtained.
1. It is possible to automate the flow stop steering operation of the towing work machine on an inclined ground.
2. The steering operation of the towing work machine during turning can be automated. 3. It is possible to eliminate the need to adjust the sensor according to the change in the hitch angle due to the alignment.
4). The above automation improves work efficiency and saves labor.
[Brief description of the drawings]
FIG. 1 is a plan view schematically showing a tractor and a working machine that are equipped with a wheel steering device according to an embodiment of the present invention and that perform harvesting work on an inclined land;
FIG. 2 is a flowchart of the wheel steering device of FIG.
FIG. 3 is a plan view schematically showing a tractor and a working machine during turning;
FIG. 4 is a plan view schematically showing an offset between a tractor and a working machine that have entered a farm with different ridge widths;
[Explanation of symbols]
1: Tractor 2: Work implement 3: Draw bar 4: Hitch 5: Draw bar sensor 6: Hitch sensor 7: Axle 8: Wheel 9: Wheel sensor 10: Hydraulic cylinder 11: Computer 12: Hitch cylinder θA: Hitch angle θB: Draw bar angle θC: deviation angle θD: target rudder angle θE: actual rudder angle θR: neutral angle S: angle difference

Claims (1)

The drawbar sensor (5) for detecting the drawbar angle θB between the drawbar (3) and the hitch (4) at the connecting portion with the tractor (1), and the axle (7) of the work machine (2) set to be offset from the hitch ), A wheel sensor (9) for detecting the actual steering angle θE of the wheel of the working machine, a hydraulic mechanism (10) for steering the wheel, In the wheel steering system comprising a computer (11) for controlling the hydraulic mechanism, the computer , when the signals of the draw bar sensor and the hitch sensor are inputted, is a deviation angle θC = θA in the traveling direction of the tractor and the work implement. -ΘB is calculated, and a target rudder angle θD of the wheel is set from the deviation angle and the neutral angle θR (normally a right angle) of the wheel so that the actual rudder angle θE matches the target rudder angle θD. Above Wheel steering system of the towing type working machine and controlling the pressure mechanism.

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