JPS62257305A - Working machine elevator of agricultural working machine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a working device elevating device for an agricultural working machine that is used with a working device such as a power tiller attached thereto.

[Prior Art] Agricultural working machines are widely used which are equipped with a working device mounting means such as a link device, and which use the mounting means to raise and lower the mounted working device such as a tiller using hydraulic pressure. In this type of agricultural machinery, when the work equipment is lowered to a predetermined set height, the hydraulic pressure is automatically stopped and the lowered position of the work equipment is maintained at the set height. It is configured.

[Problems to be Solved by the Invention] However, due to the dynamic characteristics of hydraulic oil, hydraulic systems require some time from when a stop command is issued until the operation completely stops, and the working equipment Due to the downward force due to its own weight and inertia force, it is difficult to stop immediately when descending, so in actual work, the problem arises that the working device passes through the intended lowering position.

[Means for Solving the Problems] In order to solve the above problems, the present invention has the following configuration. That is, in the agricultural working machine according to the present invention, in which the working equipment is raised and lowered by a hydraulic device equipped with an electromagnetic control valve, when the descending speed of the working equipment reaches a predetermined value or more when lowering the working equipment, the normal The electromagnetic control valve is characterized in that it is configured to operate the solenoid control valve in the direction of stopping the descending output at an earlier point in time than the descending speed of the vehicle.

[Function] If the descending speed of the working device detected by the detection means is higher than the predetermined speed, the stop output to the electromagnetic control valve is issued earlier by the corresponding amount, so that the lowering stop F position of the working device can be adjusted. It can always be kept constant.

[Example] The embodiments shown in the drawings will be described below.

FIG. 1 shows an embodiment of the agricultural working machine according to the present invention. This agricultural working machine l is provided with a link device 3 at the rear of a tractor 2, and a working device 5 (
In this example, a tiller) is installed.

The link device 3 includes one top link 1o and a pair of left and right lower links 11.11, the top link 10 is connected to the square 13 of the tiller 5, and the lower link 11.11 is connected to the transmission case 14 of the tiller 5. They are attached to both the left and right sides. The lower link 11.11 is suspended from the hydraulic lift arm 17 of the tractor 2 by lift rods 1B, 1B which are connected to the middle part thereof.

The tractor 2 has a solenoid control valve 20.2 for raising and lowering.
1 and a control device 19, the lift arm 17 is rotated up and down by the hydraulic pressure of this hydraulic device. This operation is performed using a position lever 24 provided on the side of the pilot's seat 23. Further, an angle sensor 25 is provided at the base of the lift arm 17 to detect the rotation angle of the lift arm, and the angle of the lift arm set by the position lever 24 and the actual angle detected by the angle sensor 25 are The angle of the lift arm is compared.

FIG. 2 is a block diagram of the controller 18, in which a signal for setting the position lever 24 and a detection signal from the lift arm angle sensor 25 are sent to the A/D converter 27.
is supplied to the CPU 28 via the rising valve 2.
0 and the opening/closing signal is supplied to the lowering valve 21. The electromagnetic control valves 20 and 21 are proportional solenoid valves that adjust the flow rate in proportion to the amount of energization, and are operated by pulse signals from the control device 18. A dead zone of a predetermined width is provided in advance for the setting value of the position lever 24, and when the actual position detected by the angle sensor 25 is within this dead zone, the vertical movement output is stopped. The control device 18 works to widen this dead zone and quickly issue a stop command when the lifting speed of the working device exceeds a certain speed.

FIG. 3 is a flowchart showing the operation of the control device 18. In the figure, the difference between the set position of the position lever 24 and the actual position detected by the lift arm angle sensor 25 is determined, and it is checked whether the operating direction is on the downward side. If the operation direction is on the downward side, it is checked whether the descending speed is above a certain value (allowable speed), and if it is above a certain value, the dead zone is changed from the basic value (set value when the descending speed is slow). Also, set it wider by +α. Then, the control on-time is set until the dead zone is reached.
The descending valve (solenoid valve) is opened. The size of α is
It may be set optimally depending on the type of work equipment and the characteristics of the hydraulic system. If the operating direction is on the downward side and the downward speed is smaller than a predetermined allowable speed, the dead zone is not expanded. If it is not on the descending side, the dead zone is maintained at the basic value and a check is made to see if the command is on the ascending side. In the case of the rising side, the control on-time is saved and the rising valve is opened. If it is not on the rising side, the on time is set to 0 and the output to both valves 20 and 21 is stopped.

FIG. 4 is a graph showing the relationship between the descending speed V of the work equipment and the target stopping position H, and the descending speed (Vo, V
s, V2) increases, the output stop point (
Pa+P+*P2) is located closer to the target position H than the target position H. In this way, the width of the dead zone may be changed in multiple steps depending on the magnitude of the descending speed, but normally, changing in one step is sufficient. Note that instead of expanding the width of the dead zone, the entire dead zone may be moved upward.

[Effects of the invention] This work equipment lifting device has a lowering speed that is a constant value (allowable speed) when lowering a lifted work equipment.
When it becomes larger than , the width of the dead zone where the descending side output is stopped is expanded, and the descending side output is stopped earlier than in the normal case where the descending speed is lower than the allowable speed. It is now possible to correctly stop the work equipment at the target position.

[Brief explanation of drawings]

Fig. 1 is a side view showing an embodiment of the present invention, Fig. 2 is a block diagram of the lifting device, Fig. 3 is a flowchart showing the operation of the control device, and Fig. 4 shows the relationship between descending speed and stop position. This is a hail graph.

Claims (1)

[Claims] (1) In agricultural machines that raise and lower the working equipment using a hydraulic system equipped with an electromagnetic control valve, when the working equipment is lowered, when the lowering speed of the working equipment reaches a predetermined value or higher, it is faster than the normal lowering speed. A working device lifting device for an agricultural working machine, characterized in that a solenoid control valve is configured to operate a solenoid control valve in a direction to stop a descending output at a certain point in time.