JPS6252095B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for controlling the trajectory of a working tool such as a hydraulic excavator.

FIG. 1 is a diagram showing a conventional horizontal extrusion control device for a hydraulic face shovel. In the figure, 1 is the main body of a hydraulic face shovel, 2 is a boom pivotally connected to the main body 1, 3 is an arm pivotally connected to the tip of the boom 2, 4 is a working tool, i.e., a bucket, pivotally attached to the tip of the arm 3, 5 is a boom cylinder that moves the boom 2 up and down, 6 is an arm cylinder that swings the arm 3, 7 is a bucket cylinder that rotates the bucket 4, 8 is a hydraulic pump, and 9 is between the hydraulic pump 8 and the arm cylinder 6. Arm switching valve provided in 1
0 is the boom switching valve. 11 is a level cylinder installed between boom 2 and arm 3; 12
13 is a conduit connecting the rod extrusion side chamber of the level cylinder 11 and the rod extrusion side chamber of the bucket cylinder 7; 13 is a conduit connecting the rod retraction side chamber of the level cylinder 11 and the rod retraction side chamber of the bucket cylinder 7; 14; is a cam attached to the end of the arm 3; 15 is a directional valve (shown twice for convenience) fixed to the boom 2;
The valve stem is pressed against the cam 14 by a spring. 16 is a directional control valve provided between the tank, hydraulic pump 8, and the rod extrusion side chamber pipe 17 and rod retraction side chamber pipe 18 of the boom cylinder 5;
A pilot pressure port of the directional control valve 16 is connected to the directional control valve 15. 19 is the direction control valve 16
and a flow control valve 20 provided between the pipe line 17 and the pipe line 17.
21 is a pressure reducing valve provided between the hydraulic pump 8 and the directional control valve 16, 21 is a hydraulic pump, and 22 is an output generating valve provided between the hydraulic pump 21 and the directional control valve 15.

In this horizontal extrusion control device, when the arm cylinder 6 is actuated to swing the arm 3 forward,
The level cylinder 11 is extended, and the level cylinder 1
When arm 1 extends, bucket cylinder 7 contracts, so when arm 3 swings upward, bucket belt 4 rotates downward. Furthermore, when the arm 3 is swung upward with the output generating valve 22 in the B position, the relative angle between the arm 3 and the boom changes, so the valve stem of the directional control valve 15 is pushed by the cam 14. Since the directional control valve 15 is switched to the B position, the hydraulic pump 21
Pressure oil is supplied to the pilot pressure port of the directional control valve 16, and the directional control valve 16 is switched to the B position.
For this reason, the pipe line 17 is connected to the tank via the flow rate control valve 19, and the pressure oil from the hydraulic pump 8 whose pressure has been reduced to the set pressure of the pressure reducing valve 20 is supplied to the pipe line 18, so that the boom cylinder 5 shrinks, boom 2
looks down. In this manner, when the arm 3 swings forward, the bucket belt 4 rotates downward and the boom 2 moves downward, so that the bucket belt 4 can be pushed out horizontally simply by operating the arm switching valve 9.

However, in addition to the main circuit, this horizontal extrusion control device requires a long pipe line connecting the boom cylinder 5, hydraulic pump 8, and tank, a hydraulic pump 21, a pressure reducing valve 20, etc., making the device complicated and expensive. becomes. Furthermore, since the pressure oil from the hydraulic pump 8 is supplied to the rod retraction side chamber of the boom cylinder 5, extra energy is used for horizontal extrusion. Furthermore, since the directional control valve 16 as a drain switching valve is an on-off valve, the response is unstable.

This invention was made to solve the above-mentioned problems, and provides a device for controlling the trajectory of a work tool such as a hydraulic excavator, which is simple, inexpensive, can utilize energy effectively, and has good responsiveness. The purpose is to

In order to achieve this object, the present invention includes a boom which is pivotally connected to the rod extrusion side chamber pipe of the boom cylinder and the main body and is moved up and down by the boom cylinder, and an arm cylinder which is pivotally connected to the tip of the boom. In a work tool trajectory control device for a hydraulic excavator or the like having an arm swung by an arm and a work tool attached to the tip of the arm, the rod extrusion side chamber conduit of the boom cylinder and the rod retraction of the boom cylinder are connected. A flow control valve is provided between the side chamber pipe, and a check valve is provided between the flow control valve and the rod-drawing side chamber pipe to prevent flow from the rod-drawing side chamber pipe to the rod extrusion-side chamber pipe. , connect a pipe line between the check valve and the flow rate control valve to the tank, input a relative angle signal between the arm and the boom, and output a signal to control the flow rate control valve. Provide equipment.

FIG. 2 is a diagram showing a bucket locus control device for a hydraulic excavator according to the present invention. In the figure 23
are rod extrusion side conduit 17, rod retraction side conduit 18
A flow control valve 24 is a check valve provided between the flow control valve 23 and the pipe line 18, and is a check valve provided between the flow control valve 23 and the pipe line 18.
prevent the flow to. Check valve 24 and flow control valve 2
A tank 25 is connected to the conduit between 3 and 3.
26 is a relative angle signal α ₂ between arm 3 and boom 2
or a calculation device which inputs α ₂ and the relative angle signal α ₁ between the boom 2 and the main body 1 and outputs a control signal to the flow control valve 23; 27 is provided between the calculation device 26 and the flow control valve 23; When the switch 27 is off, the flow rate passing through the flow rate control valve 23 is zero.

FIG. 3 is a block diagram showing the arithmetic unit 26.

In the figure, 29 is a differentiator, and 30 is an arithmetic unit. For example, since the angular velocity dα ₁ /dt that the boom 2 should take in order to maintain a horizontal trajectory is approximately proportional to the differential value dα ₂ /dt of the relative angle α ₂ between the boom 2 and the arm 3, α ₂ is detected and the differentiator 29 Find the velocity dα ₂ /dt of α ₂ by , input this dα ₂ /dt to the calculator 30, multiply it by a proportional coefficient, calculate dα ₁ /dt that should obtain the desired trajectory of the arm tip, and obtain the flow rate signal. Output.

In addition, when performing more strict horizontal control, as shown by the chain line in the figure, the value of α ₁ at the start of horizontal extrusion and the value of α ₁ that changes every moment are input to the calculator 30 to calculate the proportionality coefficient. If corrected, more accurate trajectory control can be performed.

Next, the operation will be explained. First, if the switch 27 is turned off, the flow rate passing through the flow rate control valve 23 is zero, and since the check valve 24 is provided, the boom 2 can be adjusted as desired by operating the boom switching valve 10. Can look up and down.
Also, turn off the switch 27 and turn off the boom switching valve 1.
0 is set to the neutral position and the arm switching valve 9 is set to the arm push-out position, the tip of the arm 3 draws a trajectory A. Furthermore, if the switch 27 is turned on, the boom switching valve 10 is set to the neutral position, and the arm switching valve 9 is set to the arm pushing position, the output of the computing device 26, that is, the control signal, enters the flow rate control valve 23.
The flow rate passing through the flow rate control valve 23 becomes a value according to the control signal, and since load pressure is always generated in the rod extrusion side chamber of the boom cylinder 5, the oil in the rod extrusion side chamber of the boom cylinder 5 changes according to the control signal. A portion of the oil flows into the rod retraction side chamber of the boom cylinder 5, and the remaining oil flows into the tank 25. Therefore, the boom cylinder 5 is retracted at a speed corresponding to the control signal, and the boom 2 is lowered at a speed corresponding to the control signal I. Therefore,
Desired trajectories such as trajectories B to E can be drawn at the tip of the arm 3.

In the above embodiment, one switch 27 was provided between the arithmetic unit 26 and the flow rate control valve 23, but two switches were provided in series, one of which
One may be turned on when the boom switching valve 10 is in the neutral position and the arm switching valve 9 is in the arm raised position. Further, in the above embodiment, a hydraulic excavator having a bucket belt 4 as a working tool has been described, but a hydraulic excavator whose working tool is an earth removal plate, a slope shaping plate, etc., a hydraulic excavator having a crane hook, a material handling machine such as a servo loader, etc. The present invention can also be applied to commercial cranes and the like.

As explained above, in the device for controlling the trajectory of a work implement such as a hydraulic excavator according to the present invention, part of the oil in the rod extrusion side chamber of the boom cylinder is supplied to the rod retraction side chamber of the boom cylinder during trajectory control. Since pressure oil from a hydraulic pump is not used to contract the boom cylinder, energy can be used effectively. Further, since the flow rate from the rod extrusion side chamber of the boom cylinder during trajectory control is controlled by a flow rate control valve and no on/off valve is used, responsiveness and control accuracy are good. Furthermore, in addition to the main circuit, it is only necessary to provide flow control valves, check valves, etc., such as a long pipe connecting the boom cylinder, hydraulic pump, and tank and equipped with an on-off valve, and a hydraulic pump for switching the on-off valve. Since there is no need to provide a pressure reducing valve or the like to prevent the pressure oil supplied to the rod retraction side chamber of the boom cylinder from exceeding a certain pressure during trajectory control, the apparatus becomes simple and inexpensive. As described above, the effects of this invention are remarkable.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a conventional horizontal extrusion control device for a hydraulic face shovel, and FIG. 2 is a diagram showing a bucket locus control device for a hydraulic excavator according to the present invention.
FIG. 3 is a block diagram showing an arithmetic unit of the trajectory control device shown in FIG. 2. 1...Shovel body, 2...Boom, 3...Arm,
4...Bucket, 5...Boom cylinder, 6...Arm cylinder, 7...Bucket cylinder, 17...Rod extrusion side chamber conduit, 18...Rod retraction side chamber conduit, 23
...Flow control valve, 24...Check valve, 25...Tank, 2
6... Arithmetic device, 27... Switch.

Claims (1)

[Claims] 1. A boom that is pivotally attached to the main body and is moved up and down by a boom cylinder, an arm that is pivoted to the tip of the boom and is swung by an arm cylinder, and the tip of the arm. In a work tool trajectory control device for a hydraulic shovel or the like having a work tool attached to A check valve is provided between the flow rate control valve and the rod intake side chamber pipeline to prevent flow from the rod intake side chamber pipeline to the rod extrusion side chamber pipeline, and the check valve and the flow rate control valve are connected to each other. Work on a hydraulic excavator, etc., characterized in that the pipe line between them is connected to a tank, and a calculation device is provided for inputting a relative angle signal between the arm and the boom and outputting a signal for controlling the flow rate control valve. Tool trajectory control device. 2 Two switches are installed in series between the arithmetic unit and the flow rate control valve, one of which is turned on when the boom switching valve is in the neutral position and the arm switching valve is in the arm up position. An apparatus for controlling the trajectory of a working implement such as a hydraulic excavator according to claim 1.