JPH088803B2 - Tilt control device for agricultural work machines - Google Patents

Description

TECHNICAL FIELD The present invention relates to a tilt control device for controlling the horizontal tilt of an agricultural work machine.

[Prior Art] Many agricultural working machines in which a working machine such as a cultivator is mounted on the tractor through a link device are equipped with a control device for controlling the tilt of the working machine in the left-right direction. This type of control device drives the hydraulic device of the tractor main unit based on the detection result of the sensor that detects the tilt of the working machine in the left-right direction, and sets the tilt angle of the working machine to a predetermined set angle (often horizontal). ).

By the way, an ON-OFF type solenoid valve is used as a hydraulic cylinder control valve of the tilt control device. The solenoid valve is shown in FIG. 5 due to the influence of the viscosity of the pressure oil, the inertial force, and the like. Thus, the operation characteristic of the hydraulic cylinder is delayed with respect to the electric output loaded on the solenoid. In order to correct the control delay due to this operation characteristic, conventionally, there is a method of detecting the control speed by reading the response for each unit time, and feeding back the detected value to the next control to adjust the timing of stopping the electric output. It was taken.

[Problems to be Solved by the Invention] However, in this method, the control speed is not accurately detected when there is mechanical play or backlash between the constituent members of the feedback mechanism. There was a problem that control could not be performed.

For example, as shown in FIGS. 7 (a), (b) and (c),
The stroke sensor 33, which is the angle sensor for the machine, is rotatably connected to the mounting shaft 51 of the sensor arm through the mounting hole 50 provided in the base portion, but the mounting hole and the mounting shaft are fitted with a margin. Therefore, when the stroke sensor extends, the mounting shaft engages with the upper portion of the mounting hole, and when the stroke sensor contracts, the mounting shaft engages with the lower portion of the mounting hole. That is, the clearance s between the mounting hole and the mounting shaft is a play, and the response of the stroke sensor to the movement of the rolling hydraulic cylinder is delayed by this clearance s. Therefore, this delay time a
Is included in the response time for measuring the control speed, the derived control speed becomes slower than the actual control speed,
The work implement cannot be kept at the set angle accurately.

Further, when the electric output for tilt control is repeatedly output alternately in the direction of moving the work machine upward and in the direction of moving the work machine downward, the electric power is output in the cycle of the natural vibration of the tilt sensor that detects the horizontal tilt of the tractor. There is also a problem that hunting may occur when the output cycles are synchronized.

[Means for Solving Problems] In order to solve the above problems, the present invention provides a tilt control device configured as follows.

That is, the tilt control device for an agricultural work machine according to the present invention is a control device for controlling the tilt in the left-right direction of an agricultural work machine in which the work machine is mounted on the tractor main unit, and the relative position of the work machine with respect to the tractor main unit. ON-O with an output signal that is output based on the detection result of the angle sensor to detect the tilt angle
A working machine rolling hydraulic device is configured to roll the working machine by driving the FF type solenoid valve, and a control speed is derived from a detection value during stable operation of the machine angle sensor, and the control speed is based on the control speed. The feature is that the output stop timing of the output signal is corrected.

[Operation] Since the operating speed of the angle sensor for this machine during stable operation is used as the control speed, the detected value becomes accurate and proper tilt control can be performed.

[Embodiment] FIGS. 1 to 3 are views showing an embodiment of an agricultural work machine according to the present invention, in which a 3P link type coupling device (3P hitch) 3 is provided at the rear of the tractor main machine 2, and the 3P The state where the rotary tiller 5 is mounted as a working machine on the hitch is shown.

The 3P hitch 3 has one top link 10 whose front ends are pivotally attached to the tractor unit 2 and a pair of left and right lower links.
A lift rod 14 and a lift rod cylinder 15, which are provided with 11, 11 'and are attached to the tips of the hydraulic lift arms 12, 12 of the tractor main unit 2, are connected to the intermediate portions of the lower links 11, 11'. The rotary cultivator 5 connects the upper end of the mounting frame 19 to the rear end of the top link 10, and
By attaching the lower part of the to the rear ends of the lower links 11 and 11 ', the 3P hitch 3 is mounted.

The pair of left and right lift arms 12, 12 are integrally attached to a hollow shaft 23 horizontally provided on the upper part of the machine frame 22 of the tractor main unit 2, and the hollow shaft 23 is mounted by a hydraulic cylinder (not shown) for lifting. By rotating, the lift arms 12, 12 are rotated up and down. Further, inside the hollow shaft 23, a rotary shaft 30 is provided so as to be rotatable with respect to the hollow shaft 23, and sensor arms 31, 31 ′ are provided at both left and right protruding ends of the rotary shaft 30. Each is integrated. A sensor arm 32 on the lift rod 14 side (left side) has a sensor rod 32, and a lift rod cylinder 20 side (right side).
The cylinder type stroke sensor is attached to the sensor arm 31 '
33 are attached respectively. The lower ends of the sensor rod 32 and the stroke sensor 33 are connected to the lower links 11, 11 'at positions near the main body of the tractor. A sensor arm 31 (lift arm) is attached to the rotary shaft 30.
A sensor arm angle sensor (lift arm angle sensor) 35 for detecting the amount of rotation of 12) is provided, and the working machine is controlled to move up and down based on the detection value of the sensor arm angle sensor.

FIG. 4 is a diagram showing the configuration of the tilt control device 40 according to the present invention. The controller 41 includes an inclination angle setting device 43 for setting the inclination degree (usually horizontal) of the working machine 5,
The stroke sensor 33 and an inclination sensor 44 for detecting the inclination degree of the tractor main unit 2 in the left-right direction are connected, and the data supplied from these are processed and an electric output is transmitted to a solenoid valve 46. This electric output excites the solenoids 46a and 46b, and the lift rod cylinder 15, which is a rolling hydraulic cylinder, expands and contracts.

The interrelationship between the electric output, the hydraulic output, and the control speed is shown in FIG. That is, since the electric output is constant, at the time of output, the valve 46 is kept fully open and the lift rod cylinder 15 expands and contracts at a constant speed. However, due to the viscosity of the pressure oil, etc., a reaction delay occurs at time a, b, c, d. Further, the length of the stroke sensor 33 changes as the lift rod cylinder 15 expands and contracts. However, due to the play of the stroke sensor connecting portion described above, the reaction of the stroke sensor 33 to the operation of the lift rod cylinder 15 is time a ', c'lag behind.

The tilt control device 40 is provided with a feedback mechanism for correcting the expansion and contraction due to the inertia of the pressure oil after the electric output is stopped to accurately stop the lift rod cylinder at the target position. The feedback mechanism detects the operation speed Δe / Δt or Δf / Δt of the stroke sensor by reading the response per unit time, and feeds this back to the next control, but detects the operation speed of the stroke sensor. After starting the expansion / contraction operation, a '
Alternatively, since the response time is set during the stable operation that does not include the time period of c'time, the detected operating speed represents the actual operating speed.

Fig. 6 shows an example in which the neutral width for turning off the output is corrected according to the response when the electro-hydraulic is off and the raising or lowering speed during output. The figure shows the horizontal axis as time. The vertical axis represents the amount of expansion / contraction of the stroke sensor. Electric output stop lines FT and ET are set at positions f and e above and below the target stop height (stop line SL) of the working machine, respectively. Here, e and f are the expansion and contraction amounts after the electric output of the stroke sensor at the time of expansion and contraction, respectively, and are derived from the expansion and contraction speeds Δe / Δt and Δf / Δt. When the working machine rises along the ascending trajectory, the electric output is stopped when the electric output stop line ET is detected.
The position of the stop line SL stops after time. Similarly, when the work implement descends along the descending trajectory, the electric output stop line
When FT is detected, the electric output is stopped, and after d hours, it stops at the position of the stop line SL.

With this configuration, it is possible to perform stable control by absorbing the influence of the viscosity due to the oil temperature difference and the influence of the flow rate balance of the hydraulic system in the tilt control.

[Effects of the Invention] As is clear from the above description, the tilt control device for an agricultural work machine according to the present invention derives the control speed from the detected value of the angle sensor against machine angle during stable operation and performs the control. Since the output stop timing of the output signal is corrected based on the speed, the control speed used for feedback is accurate, the working machine can be accurately maintained at the set angle, and hunting does not occur.

[Brief description of drawings]

FIG. 1 is a side view of an example of an agricultural working machine according to the present invention, and FIG.
FIG. 3 is a perspective view of a main part thereof, FIG. 3 is a plan view showing a part thereof in cross section, FIG. 4 is a block diagram showing a configuration of a tilt control device according to the present invention, and FIG. 6 (a) and 6 (b) are illustrations showing the mutual relationship between the output and the control speed, FIGS. 6 (a) and 6 (b) are illustrations showing an example of correction in the tilt control, and FIGS. 7 (a), 7 (b) and 7 (c) are strokes. It is explanatory drawing of the play of a sensor. 1 …… Agricultural work machine, 2 …… Tractor main machine, 3 …… 3P hitch, 5 …… Rotary tiller (work machine), 12 …… Lift arm, 15 …… Lift rod cylinder (rolling hydraulic cylinder), 31 , 31 '…… Sensor arm, 32 …… Sensor rod, 33 …… Stroke sensor (to machine angle sensor),
40 ... Tilt control device, 44 ... Tilt sensor, 46 ... Solenoid valve, 46a, 46b ... Solenoid

Claims (1)

[Claims] 1. A control device for controlling a lateral inclination of an agricultural work machine in which the work machine is mounted on the tractor,
Tractor Drives the ON-OFF type solenoid valve with an output signal that is output based on the detection result of the angle sensor for this machine that detects the relative inclination of the work machine with respect to this machine. A rolling hydraulic system is constructed, a control speed is derived from a detection value during stable operation of the machine-to-machine angle sensor, and an output stop timing of the output signal is corrected based on the control speed. Tilt control device.