JP3541496B2 - Hydraulic cylinder control device - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to a control device for a hydraulic cylinder mounted on a construction machine such as a hydraulic shovel or a work vehicle.
[0002]
[Prior art]
FIG. 9 is a control circuit diagram of the cylinder 1 described in Japanese Utility Model Laid-Open No. 6-65602. In the hydraulic circuit shown in FIG. 9, when the operation of the control valve 2 is switched from “ON” to “OFF”, a surge pressure is generated on the bottom 1a side during the switching. Thereafter, the pressure switch 4 detects that the operation is completely turned off. When the pressure sensor 5 detects that the bottom pressure is rapidly increasing, the electromagnetic switching valve 8 short-circuits the cylinder rod side line 9 and the bottom line 7 until the bottom pressure rapidly decreases. Is turned on, and the pressure oil on the bottom side can be suppressed by releasing the pressure oil on the bottom side to the rod side or the tank T. Thereafter, the force (pressure) for pushing up the boom 2 is reduced and the expansion and contraction of the cylinder 1 is accelerated. Can converge. When the pressure sensor 5 detects that the bottom side pressure drops rapidly, the electromagnetic switching valve 12 that gives a pilot signal to the safety valve-integrated negative control variable throttle 3 is turned on for a certain period of time to increase the pump discharge pressure. At the same time, the electromagnetic switching valve 10 that short-circuits the pump discharge pressure line 6 and the cylinder bottom side line 7 is similarly turned on for a certain period of time to supply the pressure oil to the cylinder bottom side.
[0003]
[Problems to be solved by the invention]
In a control circuit according to one embodiment of the prior art shown in FIG. 9, the controller 11 sends a plurality of electromagnetic switching valves based on a signal from the pressure sensor 5 so that the pressure on the bottom 1a side of the cylinder 1 stops at the holding pressure. To output a command signal. Therefore, since the controller 11 and the three electromagnetic switching valves 8, 10, and 12 are required, the configuration and the control method are complicated, and the cost of manufacturing the control circuit is high and the condition is poor. An object of the present invention is to provide a hydraulic cylinder control device that can solve the above problems.
[0004]
[Means for Solving the Problems]
According to a first aspect of the present invention, there is provided a hydraulic cylinder control device configured to prevent repetition of slight expansion and contraction swings generated when a hydraulic cylinder mounted on a construction machine is stopped. A discharge circuit is provided, and a fluctuation suppressing valve incorporating a shuttle spool is interposed in the variable pressure discharge circuit, pressure from the rod side oil chamber is applied to one end surface of the shuttle spool, and the head side oil chamber is applied to the other end surface. And the pressure receiving area of one end surface and the other end surface of the shuttle spool is set so that the shuttle spool is balanced by these pressures.The shuttle spool is connected to the rod-side oil chamber of the hydraulic cylinder. An open oil passage position is provided for communicating an oil passage connecting the tank, and one end surface side position and the other end surface side position adjacent to the open oil passage position are provided. Each of the swing suppression valves shuts off the oil passage at the shut-off oil passage position when the shuttle spool is balanced, and operates the hydraulic cylinder. When the shuttle spool moves due to a sudden fluctuating pressure immediately after stopping, the shuttle spool is switched to an open oil passage position to make the oil passage communicated and discharge the rising pressure in the rod-side oil chamber to a tank. Things.
[0005]
The invention according to claim 2 of the present application is the invention according to claim 1, wherein the pressure receiving areas of the one end face and the other end face of the shuttle spool are respectively proportional to the head pressure receiving area and the rod pressure receiving area of the piston of the hydraulic cylinder. It is set.
[0006]
The invention according to claim 3 of the present application is the invention according to claim 1 or 2, wherein the shutoff oil passage position, the open oil passage position, and the shutoff oil passage position are arranged in this order in the shuttle spool moving direction. When the holding pressure is acting on the rod side of the cylinder, the branch oil passage is closed by the shutoff oil passage position on the large pressure receiving area side.
[0007]
[Action]
In the present invention, when the hydraulic cylinder slightly expands and contracts immediately after the operation is stopped, the balance between the pressure acting on one end surface of the shuttle spool and the pressure acting on the other end surface is lost, and the difference in the force of ΔF is lost. Occurs. Then, a force (−ΔF) acts alternately on the opposite end face so as to cancel the difference ΔF in the force. Since the above-mentioned force decreases with every alternate shuttle movement of the shuttle spool, the force approaches a zero force with a curved force fluctuation approximated to a sine wave. Therefore, slight expansion / contraction swing immediately after the operation stop of the hydraulic cylinder can be quickly converged.
[0008]
【Example】
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a hydraulic cylinder control circuit diagram for implementing a hydraulic cylinder control device according to a first embodiment of the present invention. In the figure, reference numeral 13 denotes a boom mounted on the front of a construction machine or the like (a hydraulic excavator, not shown), 14 a hydraulic cylinder for driving the boom 13, 15 a piston of a hydraulic cylinder 14, and 16 a hydraulic cylinder 14. , A rod-side oil chamber as a non-load-side oil chamber, 17 a head-side oil chamber as a load-side oil chamber, 18 a swing suppression valve, 19 a shuttle spool inside the swing suppression valve 18, 20 a built-in spring, Reference numerals 21, 22, and 23 denote throttle portions, 24 an oil tank, 25 a pilot switching valve for controlling the hydraulic cylinder 14, 26 a hydraulic remote control valve for operating the hydraulic cylinder 14, 27 a main pump, and 28 a pilot pump. . FIG. 2 is a sectional view showing the swing suppression valve 18 in FIG. FIG. 3 is a hydraulic cylinder control circuit diagram showing an operation example of the swing suppression valve 18 in FIG. FIG. 4 is a sectional view showing an operation state of the swing suppression valve 18 in FIG. FIG. 5 is a curve diagram showing a fluctuating force F (F = head side oil chamber pressure × rod side pressure receiving area−rod side oil chamber pressure × head side pressure receiving area) in the head side oil chamber 17 immediately after the operation of the hydraulic cylinder 14 is stopped. It is.
[0009]
Next, a hydraulic cylinder control device according to a first embodiment of the present invention will be described with reference to FIGS. A variable pressure discharge circuit (referred to as a circuit connecting the pipes 29 and 30 shown in FIGS. 1 and 3) is provided between the oil tank 24 and the rod-side oil chamber 16 which is a no-load-side oil chamber of the hydraulic cylinder 14. A swing suppression valve 18 having a built-in shuttle spool 19 is provided in the variable pressure discharge circuit, and the pressure from the rod-side oil chamber 16 is applied to one end face 31 of the shuttle spool 19 via the throttle 21 and the other end. The pressure from the head-side oil chamber 17 is caused to act on the end face 32 via the throttle portion 22, and the movement direction of the shuttle spool 19 (in the axial direction of the shuttle spool 19 An opening oil passage position (a position indicated by reference numeral a in FIG. 1 and FIG. 3) is provided in a direction orthogonal to the direction in which the sliding movement of the sliding member 19 is performed. 32 side The pressure receiving areas A1 and A2 (shown in FIG. 3) of the one end face 31 and the other end face 32 of the shuttle spool 19 are respectively It is set in proportion to the head side pressure receiving area S1 and the rod side pressure receiving area S2.
[0010]
First, here, when the stopped hydraulic cylinder 14 repeats slight expansion and contraction swings and then comes to a rest state, the shuttle spool 19 inside the swing suppression valve 18 is in a balanced state. 1 and 2 due to the spring force. However, when the hydraulic cylinder 14 is stopped next, for example, when the boom 13 is lowered, the volume of the head-side oil chamber 17 is reduced due to the inertia force due to the load of the boom 13 and the compressibility (elasticity) of the hydraulic oil, and the force becomes △. It rises sharply by F. Since the rising pressure in the head-side oil chamber 17 acts on the other end surface 32 of the shuttle spool 19 in the swing suppression valve 18 through the pipe lines 33 and 34 and the throttle portion 22, the swing suppression valve 18 is shown in FIG. It is in the state of block oil passage position c. At this point, the pressure higher than the holding pressure is accumulated in the head-side oil chamber 17, so that the piston 15 and the boom 13 slightly rise. As the volume of the rod-side oil chamber 16 decreases and the pressure increases, the force in the head-side oil chamber 17 decreases (−ΔF). Since the pressure in the rod-side oil chamber 16 acts on the one end surface 31 of the shuttle spool 19 in the swing suppression valve 18 through the conduits 35, 36, and 37 and the throttle portion 21, it moves to the right in the illustration of FIG. I do. Accordingly, the movement of the shuttle spool 19 causes the swing suppressing valve 18 to move from the shutoff oil passage position C to the open oil passage position A as shown in FIG. During the instant of the shift, a part of the rising pressure in the rod-side oil chamber 16 passes through the pipes 35 and 29, the opening oil path position A of the swing suppression valve 18, the throttle 23, and the pipe 30, It is discharged to the oil tank 24. Thereby, the accumulated pressure in the rod-side oil chamber 16 is reduced, and the pressure for reducing the volume of the head-side oil chamber 17 is reduced. The shuttle spool 19 further moves to the right, and the swing suppression valve 18 reaches the shutoff oil passage position B. As the hydraulic cylinder 14 expands and contracts, the shuttle spool 19 also tries to continue shuttle movement to the left and right. . However, since the accumulated pressure in the rod-side oil chamber 16 is instantaneously discharged to the oil tank 24 every time the shuttle moves, the swinging energy of the hydraulic cylinder 14 decreases in a damped state similar to the curve shown in FIG. Therefore, the swing immediately after the operation of the hydraulic cylinder 14 is stopped can be quickly converged.
[0011]
FIG. 6 is a diagram illustrating a state of the swing suppression valve 18 when a holding pressure is acting on the rod-side oil chamber 16 of the hydraulic cylinder 14. As shown in FIG. 5, when the hydraulic excavator sticks the tip end of the work attachment 38 against the ground (GL) and lifts the crawler 40 on one side of the lower traveling body 39, the boom 13 is stopped. A holding pressure is generated in the rod-side oil chamber 16 of the hydraulic cylinder 14 for use. On the other hand, since the head-side oil chamber 17 is in a no-load pressure state, no pressure acts on the other end surface 32 of the shuttle spool 19 in the swing suppression valve 18. The holding pressure in the rod-side oil chamber 16 of the hydraulic cylinder 14 acts on one end surface 31 of the shuttle spool 19 through the conduits 35, 36, 27 and the throttle 21. Since the shuttle spool 19 moves to the right end in the figure, the swing suppression valve 18 is in the shutoff oil path position B. Therefore, when the holding pressure acts on the rod-side oil chamber 16 of the hydraulic cylinder 14, the swing suppression valve 18 is switched as described above, so that the holding pressure is reliably maintained and no trouble occurs.
[0012]
Next, FIG. 7 is a hydraulic cylinder control circuit diagram for implementing a hydraulic cylinder control device according to a second embodiment of the present invention. In the figure, components using the same components as those of the hydraulic cylinder control circuit in FIG. 1 are denoted by the same reference numerals. Next, a hydraulic cylinder control device according to a second embodiment of the present invention will be described with reference to FIG. A variable pressure discharge circuit is provided from the head side oil chamber 17 of the hydraulic cylinder 14 to the rod side oil chamber 17, and a swing suppression valve 18 having a shuttle spool 19 built therein is interposed in the variable pressure discharge circuit. The pressure from the rod-side oil chamber 16 is applied to the one end face 31 via the throttle section 21, and the pressure from the head-side oil chamber 17 is applied to the other end face 32 via the throttle section 22. An opening oil passage position is provided in the movement suppression valve 18 in a direction orthogonal to the direction of movement of the shuttle spool 19, and a shutoff oil passage position is provided at a position on one end surface 31 side and another end surface 32 side adjacent to the opening oil passage position a. The shuttle spool 19 is provided with the pressure receiving areas A1 and A2 (shown in FIG. 3) of the one end face 31 and the other end face 32, respectively. The hydraulic pressure is set in proportion to the head-side pressure receiving area S1 of the hydraulic cylinder 14 and the rod-side pressure receiving area S2. , 41, the check valve 42, the throttle unit 23, the opening oil passage position of the swing suppression valve 18, and the pipes 29, 35, so that the oil is instantaneously discharged to the rod-side oil chamber 16. Therefore, the point that the device of the second embodiment is different from that of the first embodiment is that the device of the first embodiment applies a sudden rising pressure from the rod-side oil chamber 16 of the hydraulic cylinder 14 via the swing suppression valve 18. In the second embodiment, the oil is instantaneously discharged from the head-side oil chamber 17 of the hydraulic cylinder 14 to the rod-side oil chamber 16 via the swing suppression valve 18 while the oil is discharged to the oil tank 24 instantaneously. It is the point which was made.
[0013]
Next, FIG. 8 is a hydraulic cylinder control circuit diagram for implementing a hydraulic cylinder control device different from the present invention. In the figure, components using the same components as those of the hydraulic cylinder control circuit in FIG. 1 are denoted by the same reference numerals. The rod-side oil chamber 16 of the hydraulic cylinder 14 and the oil tank 24 are communicated via an electromagnetic opening / closing valve 43 that opens an oil path according to a command signal, and the head-side oil chamber 17 of the hydraulic cylinder 14 and the rod-side oil chamber 16 are connected. Pressure sensors 44 and 45 for detecting the pressures of the pressure sensors 44 and 45, respectively, and the signals from the pressure sensors 44 and 45 are input to the controller 46. Based on the signals, the controller 46 calculates and determines the force 変 動 F that fluctuates. A command signal from the controller 46 is output to the solenoid 47 of the electromagnetic valve 43. When the solenoid 47 is energized by the command signal, the electromagnetic on-off valve 43 is switched from the shutoff oil passage position E to the open oil passage position, and the sudden rise pressure immediately after the operation of the hydraulic cylinder 14 is stopped is reduced. The oil is instantaneously discharged from the rod-side oil chamber 16 to the oil tank 24 through the conduits 35 and 48 and the open oil passage position of the electromagnetic on-off valve 43. Therefore, in the above-described device, the expansion and contraction swing of the hydraulic cylinder 14 can be quickly converged by using the controller 46 and the single electromagnetic switching valve 43. Although not shown, in this apparatus, the head side oil chamber 17 of the hydraulic cylinder 14 and the oil tank 24 can be communicated via the electromagnetic on-off valve 43.
[0014]
Also, as the above-mentioned device (not shown), the load-side oil chamber and the no-load-side oil chamber are communicated via an electromagnetic on-off valve, and a sudden rise in pressure immediately after the operation of the hydraulic cylinder stops is controlled by a command signal from the controller. Thus, the oil may be instantaneously discharged from the load-side oil chamber to the non-load-side oil chamber through the open oil passage position of the solenoid on-off valve.
[0015]
【The invention's effect】
In the hydraulic cylinder control device of the present invention, a variable pressure discharge circuit communicating from the oil chamber of the hydraulic cylinder is provided, and a swing suppression valve incorporating a shuttle spool is provided in the variable pressure discharge circuit to balance the shuttle spool. . The swing suppression valve is provided with an opening oil passage position in a direction orthogonal to the direction of movement of the shuttle spool, and has a closing oil passage position at one end surface side position and the other end surface side position adjacent to the opening oil passage position. With this arrangement, when the shuttle spool moves by a sudden fluctuation pressure immediately after the stoppage of the operation of the hydraulic cylinder, a sudden rising pressure can be instantaneously discharged at the opening oil passage position. Therefore, slight expansion / contraction swing immediately after the operation stop of the hydraulic cylinder can be quickly converged.
[Brief description of the drawings]
FIG. 1 is a hydraulic cylinder control circuit diagram for implementing hydraulic cylinder control inside a first embodiment of the present invention.
FIG. 2 is a cross-sectional view showing the swing suppression valve in FIG.
FIG. 3 is a hydraulic cylinder control circuit diagram showing an operation example of the swing suppression valve in FIG. 1;
FIG. 4 is a cross-sectional view showing an operation state of a swing suppression valve in FIG. 3;
FIG. 5 is a curve diagram showing a fluctuating force in the head-side oil chamber immediately after stopping the operation of the hydraulic cylinder.
FIG. 6 is a diagram illustrating a state of a swing suppression valve when a holding pressure is acting on a rod-side oil chamber of a hydraulic cylinder.
FIG. 7 is a hydraulic cylinder control circuit diagram for implementing the device of the second embodiment of the present invention.
FIG. 8 is a hydraulic cylinder control circuit diagram that implements another device different from the present invention.
FIG. 9 is a control circuit diagram of one embodiment of the prior art.
[Explanation of symbols]
5, 44, 45 Pressure sensor 11, 46 Controller 13 Boom 14 Hydraulic cylinder 16 Rod side oil chamber 17 Head side oil chamber 18 Swing suppressing valve 19 Shuttle spool 24 Oil tank 31 One end face 32 Other end face 43 Electromagnetic on-off valve

Claims (3)

In a hydraulic cylinder control device that prevents repetition of slight expansion and contraction swings generated when a hydraulic cylinder mounted on a construction machine stops,
A variable pressure discharge circuit that communicates with the oil chamber of the hydraulic cylinder is provided, and a swing control valve with a built-in shuttle spool is interposed in the variable pressure discharge circuit, and pressure from the rod-side oil chamber is applied to one end surface of the shuttle spool. By applying pressure from the head side oil chamber to the other end face, the pressure receiving area of one end face and the other end face of the shuttle spool is set so that the shuttle spool is balanced by these pressures ,
The shuttle spool has an open oil passage position for communicating an oil passage connecting the rod-side oil chamber and the tank of the hydraulic cylinder, and one end surface side position and the other end surface position adjacent to the open oil passage position. Each has a shutoff oil passage position for shutting off the oil passage,
The swing suppression valve shuts off the oil passage at the shutoff oil passage position when the shuttle spool is in a balanced state, and when the shuttle spool moves due to a sudden fluctuation pressure immediately after the operation of the hydraulic cylinder is stopped. A hydraulic cylinder control device configured to switch to an open oil passage position to make the oil passage communicated, and to discharge a rising pressure in the rod-side oil chamber to a tank . 2. The hydraulic cylinder control device according to claim 1, wherein the pressure receiving areas of the one end face and the other end face of the shuttle spool are set in proportion to the head pressure receiving area and the rod pressure receiving area of the piston of the hydraulic cylinder, respectively . In the moving direction of the shuttle spool, the shutoff oil passage position, the opening oil passage position, and the shutoff oil passage position are arranged in this order, and when the holding pressure is acting on the rod side of the hydraulic cylinder, the shutoff on the large pressure receiving area side is performed. 3. The hydraulic cylinder control device according to claim 1, wherein the branch oil passage is closed by an oil passage position .

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