JPH0726562Y2 - Hydraulic actuator drive - Google Patents

Description

[Detailed Description of the Invention] A. Field of Industrial Application The present invention calculates the required flow rate of the hydraulic actuator to determine the stroke amount and direction of the directional flow rate adjusting valve, and thereby controls the speed of the hydraulic actuator. The present invention relates to an actuator drive device.

B. Prior Art The present applicant previously proposed a readerless earth auger in which a hydraulic actuator driving device of this type is used in Japanese Patent Application No. 62-51478.

In this machine, a first arm is rotatably attached to an upper revolving structure of a hydraulic excavator body, a second arm is attached to the tip of the first arm, and a third arm is attached to the tip of the second arm.
Each of the arms is rotatably attached. These first, second, and third arms are each driven by a hydraulic cylinder, an auger machine is attached and suspended at the tip of the third arm, and an auger screw is rotatably attached to the lower end thereof. Then, by operating the trajectory control lever, for example, the first arm is fixed, the trajectory of the second and third arms is controlled, and the tip of the third arm is lowered with the same radius. The August screw attached to the tip of the arm 3 descends vertically while rotating and a hole is made in the ground.

FIG. 5 shows a conventional example of a hydraulic cylinder drive circuit for a work machine of this type. The arithmetic unit 1 calculates the required flow rate of each hydraulic cylinder so that the tip of the third arm draws a vertical locus, and outputs a flow rate command to the electromagnetic proportional pressure reducing valve 2 via the signal line l ₁ or l ₂ . The electromagnetic proportional pressure reducing valve 2 sends the pilot pressure according to the flow rate command to the directional flow rate adjusting valve 3 via the pilot line Pl ₁ or Pl ₂ . Further, according to the pilot pressure, the spool of the directional flow control valve 3 strokes in a predetermined direction to open a predetermined opening area, and the required flow rate is sent from the hydraulic pump 4 to the hydraulic cylinder 5. At this time, the high pressure on the hydraulic cylinder 5 side is controlled by the high pressure selection valve 6a so that the pressure adjustment valve 6b
The pressure difference between the pump side pressure of the directional flow rate adjusting valve 3 and the hydraulic cylinder side pressure is constantly kept constant, whereby the flow rate change due to pressure fluctuation is controlled and the required flow rate is supplied to the hydraulic cylinder 5. Note that FIG. 5 shows a drive circuit for one of the two arms driven for trajectory control.

FIG. 6 schematically shows the hydraulic circuit in the case where the spool of the directional flow control valve 3 holds the stroked opening area. In Figure 6, A1, A2
Represents the opening area of the directional flow rate adjusting valve 3 on the pump discharge side and the tank return side, and P1, P2, P3, and P4 represent the pressures at respective points in the figure. When a load in the direction of arrow a is applied to the hydraulic cylinder 5 when the hydraulic cylinder 5 is contracted, the pipelines 7, 8
Pressure is P2> P3, and the high pressure selection valve 6a
The pressure P2 is guided to 6b, and the differential pressure between the pressures P1 and P2 before and after the directional flow rate adjusting valve 3 on the pump discharge side is kept constant. If the difference between the pressures P1 and P2 does not change, the flow rate corresponding to a certain opening area A1 becomes substantially constant, so the command value to the electromagnetic proportional pressure reducing valve 2 is calculated according to the required flow rate calculated by the trajectory control calculation. As a result, when the directional flow rate adjusting valve 3 is stroked to drive the hydraulic cylinder 5, locus control becomes possible.

C. Problems to be solved by the device However, when the hydraulic cylinder 5 is contracted when a load in the b direction is applied to the hydraulic cylinder 5, the pipelines 7, 8
Pressure becomes P2 <P3, and the high pressure selection valve 6a
The pressure P3 is guided to 6b, and the differential pressure between the pressures P1 and P2 changes depending on the load direction of the hydraulic cylinder 5. Therefore, the flow rate flowing through the controlled opening area A1 to drive the hydraulic cylinder 5 at the same speed as in the load a direction is different, and different flow rates are sent to the hydraulic cylinder 5 despite the same command value. As a result, the deviation of the trajectory control from the reference position becomes large, and desired accuracy cannot be obtained.

The opening area A1 may be corrected by monitoring the load direction with a sensor, but a sensor is required, and the number of calculations in the calculation device increases, which causes a cost increase.

It is an object of the present invention to provide a hydraulic actuator drive device that supplies a required flow rate calculated to a hydraulic actuator regardless of the direction of a load acting on the hydraulic actuator.

D. Means for Solving the Problems Referring to FIG. 1 showing an embodiment, the present invention provides a pair of pipelines connecting a hydraulic pump 63 and a tank to a cylinder bottom side chamber or a cylinder rod side chamber of a hydraulic cylinder 26. Directional flow rate adjusting valve 64, which is installed in 65, 66, 68, 69 and adjusts the driving direction and the driving speed in the hydraulic cylinder 26, the position of the work target (24) driven by the hydraulic cylinder 26, and its driving command signal. The calculation means 41 for calculating the required flow rate to be supplied to the hydraulic cylinder 26 and the driving direction based on the calculation result, and outputting the driving command to the direction flow rate adjusting valve 64 based on the calculation result, and the direction based on the calculated driving command based on the algae. The drive means 61 for driving the flow rate adjusting valve 64 and the pair of pipelines 68, 69 between the directional flow regulating valve 64 and the hydraulic cylinder 26 are provided between the two, and the high pressure in either of the pipelines (68, 69) is high. High pressure to select pressure oil in side pipe A selection valve 67a, the pressure oil selected by the high pressure selection valve 67a, the pressure compensating valve for controlling the discharge pressure oil supplied from the hydraulic pump 63 to the directional flow control valve 64 to a predetermined pressure
67, a pair of conduits 68, 69 between the high pressure selection valve 67a and the hydraulic cylinder 26, and a pair of check valves 70b, 71b for allowing only the flow of pressure oil from the directional flow rate adjusting valve 64 to the hydraulic cylinder 26. Counterbalance valve members 70a, 71 for adjusting the opening area of the other pipeline by the pressure oil in one of the pipelines (68, 69)
The above-mentioned problems are solved by providing the counter balance valves 70 and 71 composed of a and a, respectively.

E. The case where the operation direction flow rate adjusting valve 64 communicates with P-A and B-T will be described. When the hydraulic actuator 26 is contracted against the load a acting on the hydraulic actuator 26, the hydraulic pump 63
The discharge oil is P port, A port, counter balance valve
Flowing to the hydraulic actuator 26 through the route 70, a predetermined pressure is established in the pipe line 68. Therefore, the counterbalance valve 71 on the return side of the hydraulic actuator 26 has a sufficiently large throttle area, and the pressure of the pipe line 68 on the pump discharge side is equal to the line on the tank return side.
Higher than 69 pressure.

On the other hand, when the hydraulic actuator 26 is contracted in the same direction as the load b acting on the hydraulic actuator 26, sufficient pressure does not rise in the pipe line 68 on the pump discharge side. The pressure is reduced, and a pressure substantially equal to that in the case of the load a is established in the pipe line 68 on the pump discharge side, and the pressure in the pipe line 69 on the tank return side is sufficiently low. Now, since the pressure compensation valve 67 makes the pressure difference between the P port and the A port of the directional flow regulating valve 64 constant by the high pressure side pressure in the pump discharge side pipe line 68 and the tank return side pipe line 69, As described above, regardless of the load direction acting on the hydraulic cylinder 26, if the pressure of the pipeline 68 is set to a substantially constant high pressure and the pipeline 69 is set to the tank pressure, a predetermined opening area is provided. The passing flow rate is controlled to be constant, and highly accurate driving is performed.

F. Embodiment One embodiment of the present invention will be described with reference to FIGS. First, an articulated arm working machine in which the hydraulic actuator drive system according to the present invention is used will be described with reference to FIG.

In FIG. 3, a first arm 21 is rotatably attached to a rotary fulcrum 22 on the upper revolving structure 1.
Is driven by the first arm cylinder 23. First
A second arm 24 is rotatably attached to a rotation fulcrum 25 at the tip of the arm 21, and the second arm 24 is driven by a second arm cylinder 26. A third arm 27 is rotatably attached to a rotation fulcrum 28 at the tip of the second arm 24, and the third arm 27 is a third arm cylinder.
Driven by 29. An auger machine 31 is suspended by a pin 30 at the tip of the third arm 27.
August Cru 32 by the motor and reducer built into
Is driven.

Further, in FIG. 3, in the vicinity of the rotation fulcrum 22 of the first arm 21, a ground angle meter for detecting the ground angle of the first arm 21.
33 is provided, and the rotation fulcrum 25 of the second arm 24 and the third
Relative angle meters 34 and 35 for detecting a relative angle are respectively provided on a fulcrum 28 of rotation with respect to the arm 27. Here, the relative angle is an angle formed by the axis of the first arm and the axes of the second and third arms. A weight pendulum type angle meter is used as the ground angle meter 33, and a potentiometer or a rotary encoder is used as the relative angle meters 34 and 35.

FIG. 4 shows a schematic configuration of the entire control system.

Outputs α ₁ , θ ₂ , θ _{3 from the} ground angle meter 33, relative angle meters 34, 35
Is input to the arithmetic control circuit 41 having a microprocessor or the like. 42 is an arm length setting device, which is the first to third arms
Set the reference length l ₁ to l ₃ of 21, 24, 27 with the key and the operation control circuit
Enter in 41. In addition, 43 is a locus control operation lever 43a.
Is a speed signal setting device that raises and lowers the earth auger 31 while keeping the same work radius at a work speed corresponding to the operation amount of, from which a speed command signal v is input to the arithmetic control circuit 41.

The arithmetic control circuit 41 performs a locus control arithmetic as disclosed in, for example, Japanese Patent Publication No. 61-45025. In this example, vertical locus control is performed so that the locus of the tip Co of the third arm 27 is constant at the working radius R =. Further, in FIG. 4, the arithmetic control circuit 41 calculates the expansion / contraction amount of each hydraulic cylinder 26, 29 so as to vertically press the earth auger 31, and the hydraulic cylinder 26, 29 is compressed.
To the hydraulic drive circuit 60 that controls expansion and contraction of the drive signals i ₁₁ , i ₁₂ ,
Supply i ₂₁ , i ₂₂ .

FIG. 1 is a diagram for explaining the hydraulic drive circuit 60, and FIG.
Only the hydraulic cylinder 26 that drives the arm 24 is shown in FIG. The hydraulic drive circuit 60 has electromagnetic proportional pressure reducing valves 61 and 62, and the above-mentioned drive signals are supplied to these solenoid parts 61S and 62S.
i ₁₁ , i ₁₂ are supplied. The output ports of the electromagnetic proportional pressure reducing valves 61, 62 are pilot ports 64a, 64b of a directional flow rate adjusting valve 64 provided between the hydraulic pump 63 and the hydraulic cylinder 26.
When the electromagnetic proportional pressure reducing valves 61 and 62 output secondary pressure in accordance with the input drive signals i ₁₁ and i ₁₂ , the switching direction and opening area of the directional flow control valve 64 are changed in accordance with the secondary pressure. Is controlled.

Further, the pressure adjusting valve 67 is provided between the pipe lines 65 and 66 connected to the P port and the T port of the directional flow adjusting valve 64, respectively.
A high pressure selection valve 67a is provided between the pipe lines 68 and 69 connected to the A port and the B port, respectively. Here, the high pressure selection valve 67a and the pressure adjustment valve 67b are the pressure compensation valve 67a.
The pressure difference between the P port of the directional flow control valve 64 and the A and B ports is kept constant. Further, counter balance valves 70 and 72 are provided in a pipe line 68 that communicates between the cylinder chamber of the hydraulic cylinder 26 and the A port, and a pipe line 69 that communicates between the bottom chamber and the B port. Each of the counterbalance valves 70 and 71 has a valve member 70a, 71a having a throttle area corresponding to the pressure on the pipes 68, 69, and check valves 70b, 71b opened by the pressure of the pipes 68, 69. . 72 is
A pilot hydraulic circuit relief valve, 73 is an actuator drive circuit relief valve, and 74 is a pilot hydraulic pump.

Next, the operation will be described.

In the working machine thus configured, firstly,
A desired working radius is obtained by operating the third arm drive operating lever. Next, the trajectory control operation lever 43
When a is operated, the operation control circuit 41 calculates the work radius R ₀ at the start of the operation from a predetermined calculation formula, and the work of vertically traversing the tip Co of the third arm 27 is started at this work radius. The speed signal setting device 43 uses the speed signal v in order to lower the earth auger 31 at a speed according to the operation amount of the lever 43a.
Is input to the arithmetic control circuit 41. Arithmetic control circuit 41
Is the coordinates (R ₀ , Y ₀ ) of the tip position Co of the arm 27 shown in FIG. 3 and the arm according to the input signals from the relative angle meters 34, 35.
Calculate the coordinates of 24 tip positions Bo. Furthermore, from C ₀ to ΔY ₁
The coordinates (R ₀ , Y ₀ −ΔY ₁ ) of the target point C _{1 at} the tip position of the arm 27 below is determined, and thirdly, when the tip of the arm 27 moves to the target point C ₁ , the second arm The coordinates of the target point B ₂ where the tip Bo of 24 should be located are calculated. The required flow rate to be supplied to each hydraulic cylinder 26, 29 is calculated from the calculation result regarding these target points C ₁ , B ₂ and the speed designation signal v.
Then, based on the result, drive signals i ₁₁ and i ₁₂ are output to the electromagnetic proportional pressure reducing valves 61 and 62. The electromagnetic proportional pressure reducing valves 61, 62 are
The secondary pressure that is operated according to the input drive signals i ₁₁ and i ₁₂ and that follows the operation amount is supplied to the pilot port of the directional flow control valve 64. As a result, the directional flow control valve 64 strokes in the direction corresponding to the secondary pressure by a predetermined amount, and a pump discharge side passage having an opening area corresponding to the required flow rate is formed between the P port and the A port, for example, and is connected to the T port. A tank return side passage is formed between the B ports, and the oil discharged from the hydraulic pump 63 is supplied to the cylinder 26 and returns to the tank. As a result, the cylinder 26 expands and contracts at a predetermined speed.

FIG. 2 schematically shows the hydraulic circuit when the spool of the directional flow control valve 64 is stroked by a predetermined amount to maintain the opening area between the P port and the A port. In FIG. 2, A1 and A2 are directional flow control valves 64
The opening areas between the P port and the A port and between the T port and the B port, and P1, P2, P3, and P4 represent the pressure at each point in the figure. When the hydraulic cylinder 26 is contracted when a load in the direction of arrow a acts on the hydraulic cylinder 26, the hydraulic pump 63
The discharged oil is sent to the cylinder chamber by opening the check valve 70b of the counter balance valve 70. At this time, the valve member 71a of the counterbalance valve 71 is sufficiently opened by the pressure rising in the pipe 68, so that the valve member of the counterbalance valve 71 from the bottom chamber is opened.
It flows to the tank through 71a between T port and B port. Therefore, the pressure in both pipes 68 and 69 is P2> P3, and the pressure P2 is guided to the pressure adjusting valve 67b by the high pressure selection valve 67a.

On the other hand, when the hydraulic cylinder 26 is contracted when a load in the direction of arrow b acts on the hydraulic cylinder 26, the discharge oil of the hydraulic pump 63 opens the check valve 70b of the counter balance valve 70 and is sent to the cylinder chamber. At this time, the pressure rising in the pipe 68 is lower than in the load direction a, and the counter balance valve 71
The pipe 69 is throttled by the valve member 71a. Therefore, the pressure P2 in the conduit 68 does not become a low pressure as in the case of the conventional FIG. 6 and becomes almost the same pressure in the load a direction, and moreover, from the bottom chamber through the valve member 71a of the counterbalance valve 71. Pipe line 69 that flows to the tank through the T port and the B port
Since the pressure P3 in FIG. 3 is almost the same as the tank pressure in the load direction a, P2> P3 as in the case of the load direction a, and the high pressure selection valve 67a guides the pressure P2 to the pressure adjusting valve 67b. As a result, the pressure difference between the pressures P1 and P2 before and after the directional flow control valve 64 between the P port and the A port is kept constant regardless of the load direction. If the difference between the pressures P1 and P2 does not change, there is a certain opening area A
Since the flow rate corresponding to 1 is almost constant, the electromagnetic proportional pressure reducing valves 61, 62 are operated according to the required flow rate obtained by the trajectory control calculation.
The locus control becomes possible by obtaining the command value to the hydraulic cylinder 26 by making the stroke of the directional flow control valve 64 by this.

The present invention does not have the first to third arms as described above, but has the first arm rotatably attached to the upper revolving structure and the rotation at the tip of the first arm. The present invention can also be applied to a hydraulic excavator having a second arm movably attached and having a work attachment attached to the tip of the second arm. Furthermore, not only the articulated arm working machine, but also the necessary flow rate to be supplied to the hydraulic actuator in order to cause the working machine to perform a predetermined operation is calculated, and the stroke amount of the directional flow control valve 64 is calculated based on this calculated flow rate. INDUSTRIAL APPLICABILITY The present invention can be applied to a drive device for a working machine equipped with hydraulic actuators that are driven and that have loads acting in opposite output directions. Further, the case where the hydraulic cylinder is used as the hydraulic actuator has been described, but a drive circuit of another hydraulic actuator such as a hydraulic motor or a hydraulic rotary actuator may be used.

G. Effect of the Invention According to the present invention, the pressure difference before and after the passage of the directional flow control valve is made constant regardless of the load direction acting on the hydraulic actuator, and the calculated necessary amount is supplied to the hydraulic actuator. Highly accurate control is possible. For example, if the present invention is used as a trajectory control device for a leaderless earth auger as a multi-joint arm working machine, the trajectory of the auger becomes almost constant even when the load directions of the hydraulic actuators are opposite such as pushing and pulling the auger. Accuracy is improved. Further, since the sensor for detecting the load direction is unnecessary and the flow rate correction calculation based on the load direction is also unnecessary, the accuracy can be improved without increasing the cost of the device.

[Brief description of drawings]

1 to 4 show an embodiment in which the present invention is applied to a readerless earth auger which is a multi-joint arm working machine. FIG. 1 is a circuit diagram of a hydraulic cylinder drive circuit thereof, and FIG. 2 is a schematic diagram thereof. FIG. 3 and FIG. 3 are diagrams showing a working example of the earth auger, and FIG. 4 is a block diagram showing the entire control system thereof. FIG. 5 is a circuit diagram of a conventional hydraulic cylinder drive circuit, and FIG. 6 is a schematic diagram thereof. 21: First arm 24: Second arm 27: Third arm 23,26,29: Hydraulic cylinder 33: Ground angle meter 34,35: Relative angle meter 41: Arithmetic control circuit 43: Speed signal setting device 60 : Hydraulic cylinder drive circuit 61,62: Electromagnetic proportional pressure reducing valve 64: Directional flow rate adjusting valve 67: Pressure compensating valve 67a: High pressure selecting valve 67b: Pressure adjusting valve 68,69: Pipe line 70,71: Counter balance valve

Claims (1)

[Scope of utility model registration request] 1. A directional flow rate adjusting valve for interposing a hydraulic pump and a tank in a pair of conduits connecting to a cylinder bottom side chamber or a cylinder rod side chamber of a hydraulic cylinder and adjusting a driving direction and a driving speed of the hydraulic cylinder. , A required flow rate to be supplied to the hydraulic cylinder and a drive direction are calculated based on a position of a work object driven by the hydraulic cylinder and a drive command signal thereof, and a drive command is output to the directional flow rate adjusting valve based on the calculation result. And a driving means for driving the directional flow rate adjusting valve based on the calculated drive command, and provided between the pair of pipelines between the directional flow rate adjusting valve and the hydraulic cylinder, The high-pressure selection valve that selects the pressure oil in the high-pressure side of either of the two pipelines and the hydraulic oil that is selected by the high-pressure selection valve From the directional flow regulating valve to the pressure compensating valve for controlling the discharge pressure oil supplied from the pump to the directional flow regulating valve to a predetermined pressure, and to the pair of pipelines between the high pressure selection valve and the hydraulic cylinder. A counterbalance valve including a check valve that allows only the flow of pressure oil to the hydraulic cylinder and a counterbalance valve member that adjusts the opening area of the other pipeline by the pressure oil of one pipeline of the pair of pipelines. And a hydraulic actuator drive device characterized by comprising: