JPH01189375A - Electro-hydraulic actuator - Google Patents

Abstract

PURPOSE:To automatically disconnect a hydraulic cylinder from apparatus, etc., when the control capacity of an actuator exceeds the range of a capacity threshold diagram by providing an oil path stop valve so as to communicate both cylinder chambers of the hydraulic cylinder. CONSTITUTION:A hydraulic piston 5 for dividing the inside of the hydraulic cylinder 4 to the two hydraulic cylinder chambers, a servo valve 9 connected to the respective hydraulic cylinder chambers via pipelines 61, 62 in order to supply a pressure oil to said chambers, a hydraulic power unit 10 which supplies the pressure oil to the valve 9, a bypass pipeline 7 which communicates the pipelines 61, 62 to each other and the oil path stop valve 8 which opens and closes the pipeline 7 are provided. An oil path stop valve driving circuit 13 for controlling the opening and closing of the valve 8 and a switch 12 for controlling the valve 9 are provided. The circuit 13 is connected to a sensor 14 to detect the position, speed and load pressure of the piston 5 or the physical quantities equal thereto and further a servo amplifier 11 for driving the valve 9 is provided and is connected to the switch 12.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) The present invention relates to an electro-hydraulic actuator that is suitable for two uses: controlled and uncontrolled.

2. Description of the Related Art Conventionally, an electro-hydraulic actuator has been known as a type of vibration generator.

A typical configuration of a conventionally known electro-hydraulic actuator is now schematically shown in FIG. 4 of the accompanying drawings. That is, as shown in the figure, this electro-hydraulic actuator uses a servo valve 21 controlled by an electrodynamic vibration generator 20 to vibrate an actuator 22 (a vibration generator having a piston 23) using hydraulic pressure. This method has the characteristics of being able to produce objects with extremely large vibration force, and being able to obtain large displacements and high speeds. Widely used in the field. The operating principle of this electro-hydraulic actuator is that the spool 25 of the hydraulic valve 25 of the pilot stage 24 of the servo valve 21. is driven up and down by the electrodynamic vibration generator 20, this hydraulic valve 2
The pressure oil at pressure P supplied from the hydraulic pipe 26 to 5 is
It acts on the top and bottom of the spool 281 of the hydraulic valve 28 of the power stage 27 of the servo valve 21, and supplies the pressure oil at the pressure P supplied from the hydraulic pipe 29 of this hydraulic valve 28 to the top and bottom of the piston 23 of the actuator 22. This causes the piston 23 of the actuator 22 to vibrate up and down, and the diaphragm 30 connected to the piston 23 to vibrate.

In this way, when the hydraulic valve 28 of the power stage 27 performs vibration displacement under the control of the electrodynamic vibration erection generator 20,
Along with this, the pressure oil flowing in and out of the piston 23 of the actuator 22 above and below changes via the power stage 27, and a vibration speed proportional to the change is generated in the diaphragm 30. The electro-hydraulic system of this electro-hydraulic actuator forms a feedback loop, and the electro-dynamic vibration generator 20 in the servo valve 21 is driven by the difference signal between the input signal and the feedback signal. However,
The frequency response of this electro-hydraulic actuator is due to the springiness due to the compressibility of oil and the mass of the moving part including the test specimen.
It is well known that it is theoretically calculated that a spring-mass system is formed and resonates, and that the frequency response is maximum at a certain frequency, but the details are beyond the scope of this invention. Since it is not directly related, detailed explanation will be omitted here.

Furthermore, there are certain limitations to the performance of an electro-hydraulic actuator that has such a typical configuration due to its configuration and the rated flow rate of the attached servo valve, and this is determined by the frequency. A qualitative representation of the relationship with displacement is as shown in Figure 5 of the attached drawings, but this diagram is called the "capacity limit diagram" in boat fishing. As can be seen from this diagram, the displacement of the actuator is
Up to a certain frequency, there is a limit range determined by the length of the hydraulic cylinder, followed by a speed limit range determined by the rated flow rate of the servo valve, and then further by the piston of the hydraulic cylinder. There is an acceleration limit area determined by the cross-sectional area of the motor and the hydraulic pressure. Therefore, the electro-hydraulic actuator can operate only within the hatched area surrounded by these restricted areas in the diagram.

Thus, this type of electro-hydraulic actuator
It must be designed to be used only within the capacity limit diagram defined by the specifications.

It is impossible in terms of performance to move the hydraulic piston beyond the range of the capacity limit diagram.

Therefore, when using conventional electro-hydraulic actuators to control vibrations of equipment that vibrates in response to external disturbances, such as seismic isolation devices, the vibrations of the equipment increase as the disturbance increases, and the electro-hydraulic When a situation arises in which the range of the capacity limit diagram of the type actuator is exceeded, it is necessary to separate the hydraulic cylinder from the equipment. In addition, if it were not to be disconnected, it would be necessary to use an electro-hydraulic actuator that has a capacity limit performance that exceeds the expected vibration of the equipment.

However, in the former case, the mechanism of the disconnection means is complicated, and in the latter case, an electro-hydraulic actuator with more capacity than necessary is used, making it inconvenient. It becomes the economy.

Fl　　゛　.

Therefore, as described above, the present invention solves the problems with conventionally known electro-hydraulic actuators, and provides an improved and novel actuator that has the minimum capability required for control and does not need to be separated from equipment. The objective is to obtain an electrically powered actuator.

. In order to achieve this object, the present invention is disclosed in the first part of the accompanying drawings.
As shown in the figure, each hydraulic cylinder chamber is divided by a hydraulic cylinder (4), a piston (5) movably attached inside the hydraulic cylinder, and a hydraulic piston (5) inside the hydraulic cylinder (4). Each pipe line (61, 62) connected to each oil line (a, d) for supplying pressure oil to
), a servo valve (9) having an oil line (eJ, g, h, e'J') connectable to each pipe line (6, 62), and a servo valve (9). A hydraulic power unit (10) having pipes (1o, , to2> that can be connected to each oil pipe) and pipes (63, L) from each hydraulic cylinder chamber of a hydraulic cylinder (4) are connected to each other. It has a bypass pipe line (7) connected to the bypass pipe line (7) and an oil line on-off valve (8) for opening and closing the bypass line (7), and also controls the opening and closing of the oil l on-off valve (8). Oil passage opening/closing valve drive circuit (
13) and a switch for controlling the servo valve (9) (
12), and the oil passage opening/closing valve drive circuit (13) is
A servo amplifier (14) connected to a sensor (14) for detecting the position, speed, load pressure, or physical quantities equivalent to these of the hydraulic piston (5), and further driving a servo valve (9).
11) is provided, which features an electro-hydraulic actuator connected to the switch (12).

Dog-JLJL Hereinafter, the present invention will be described in figures 1 to 3 of the attached drawings showing one embodiment thereof.
A detailed explanation will be given based on the figures.

First, in FIG. 1, an electro-hydraulic actuator according to the present invention is used as a device that vibrates in response to disturbance, and a seismic isolation device 2 placed on the horizontal ground or on the floor surface 1 of a building is shown. When the disturbance is small, an excitation force is actively applied to it, but when the disturbance becomes large, it is applied to allow it to vibrate freely. , Eight devices 3 to be seismically isolated are placed on top of the seismic isolation device 2, and the transmission of external disturbances (earthquake force, etc.) from the ground etc. 1 to the devices 3 is suppressed as much as possible. There is. As shown schematically in FIG. 1, this seismic isolation device 2 includes an elastic member 2. and Wt shock absorber 22, and when the ground 1 etc. vibrates during an earthquake, the seismic isolation device 2 performs a seismic isolation effect by the action of these members. However, due to the nature of this seismic isolation device 2,
When a disturbance such as an earthquake is applied, the seismic isolation effect is relatively small if the disturbance is small, and the original seismic isolation effect can only be achieved when the disturbance becomes large enough. 2 is connected to the electro-hydraulic actuator 20 according to the present invention, and when the disturbance is small, it actively applies an excitation force to the seismic isolation device 2, but when the disturbance is large, no resistance force is applied to the seismic isolation device 2. This allows the seismic isolation device 2 to exert the maximum seismic isolation effect regardless of the magnitude of the disturbance.

Now, the electro-hydraulic actuator 20 according to the present invention has, as its hydraulic circuit, a hydraulic cylinder 4 constituting the actuator, a hydraulic piston 5 housed inside the hydraulic cylinder 4 so as to be able to reciprocate, and the hydraulic piston 5. There is an oil passage a in both cylinder chambers of the hydraulic cylinder 4 divided by
and multi-tube I86. connected at d. and 6□, respectively, are connected to a bypass pipe 7 at intermediate points C and C, an oil passage opening/closing valve 8 connected to open and close this bypass pipe, and each pipe 65. ,6
A servo valve 9 is connected to the end of □ upstream of the oil passage on-off valve 8, and a pipe line 10 is connected to this servo valve 9, respectively.
．． and 10. It consists of a hydraulic power unit 10 connected via a hydraulic power unit 10. In addition, as an electric circuit for electrically controlling this hydraulic circuit, the seismic isolation device W2 receives electric signals such as displacement and acceleration of the equipment 3 placed on it, and converts these signals into appropriate electric signals. A servo amplifier 11 for converting into a servo amplifier 11, a switch 12 for opening and closing the electrical connection between this and the servo valve 9, and a wire 13 to the switch 12.
The oil passage opening/closing valve driving circuit 13 is connected to the oil passage opening/closing valve driving circuit 13 via the line 13.
In addition to being connected to the electromagnetic element of the oil passage opening/closing valve 8 via line 14+, it is also connected to the sensor 14 via line 14+. Switch 12 connects line 12. The sensor 14 detects the position, speed, and load pressure of the hydraulic piston 5 of the hydraulic cylinder 4, or physical quantities equivalent to these. as an electrical signal, line 14. The oil is supplied to the oil passage opening/closing valve drive circuit 13 via.

The present invention has such a configuration, and next, its operation will be explained as it is applied to a seismic isolation device 2, as shown in FIG.

First, the hydraulic piston 5 of the hydraulic cylinder 4 constituting the electro-hydraulic actuator 20 according to the present invention has a maximum stroke of 2L, as shown in FIG. , the sensor 14 constantly detects the position of the hydraulic piston 5, the speed of the piston 5, the load pressure, etc., and this detected value is supplied as an electric signal to the oil passage opening/closing valve drive circuit 13 via the line 141. As explained in Fig. 5, the hydraulic piston 5 is controlled within the operable range of its limit performance diagram (see the hatch in Fig. 5).
The stroke during control is 21 (<2L).
It is designed to be.

The oil passage during this control is shown in Figure 2.
As shown in the figure, in this state, the position, speed, load pressure, or equivalent physical quantity of the hydraulic piston 5 of the hydraulic cylinder 4 is detected by the sensor 14, and the detected value is
When the oil passage opening/closing valve drive circuit 13 determines that the values are within the respective preset values, the oil passage opening/closing valve driving circuit 13 issues a signal to that effect, and based on this, the line 132 The oil passage opening/closing valve 8 is operated through the pipes 61 and 6 communicating with the oil passages a and d of the hydraulic cylinder 4.
The bypass circuits 7 connected to each other at points □ and C are cut off. At the same time, the switch 12 is turned "closed" by a signal from the oil passage opening/closing valve drive circuit 13. In this state, the servo valve 9 is operated, and the pipe lines 8. ．． 62 to the oil passages e and f of the servo valve 9, or the oil passages e° and r
The pipes 61, 6□ are connected to the pipes 10° and 10., respectively. via the oil tank 10. of the hydraulic power unit 10, respectively. and hydraulic power source 10. or vice versa, so that the hydraulic piston 5 of the hydraulic cylinder 4 is moved to the left or to the right as seen in FIG. Vibratory motion is applied, thereby applying an excitation force to the seismic isolation bag M2 in a mi manner.

On the other hand, if the disturbance becomes large and the position, speed, load pressure of the hydraulic piston 5 of the hydraulic cylinder 4, or one of the physical quantities equivalent to these exceeds the set value, as shown in FIG. The oil passage opening/closing drive valve drive circuit 13 communicates the oil passage opening/closing valve 8 with the bypass pipe 7 that connects the oil passages a and d of the hydraulic cylinder 4 at locations and C, and also, At the same time, the switch 12 is opened,
As a result, the servo valve 9 connects the pipes 61 and 62 and the pipe 1.
0+, an oil passage g that cuts off communication between 102 and 102;

It will take the position h. In this way, the electro-hydraulic actuator 20 according to the invention is in an uncontrolled state.

In this state, the hydraulic oil in the hydraulic cylinder 4 can freely move through the pipe 6.6□, the oil passage opening/closing valve 8, and the bypass pipe 7 as the hydraulic piston 5 moves. become. Therefore, the seismic isolation device 2 can move freely without receiving any resistance from the hydraulic-electric actuator 20.

For reference, the operation of the oil passage opening/closing valve drive circuit 13 is shown in a flowchart as shown in FIG.

The optical W knee of the present invention has the above-described configuration and operation, and in particular, the oil passage opening/closing valve 8 is provided so that both cylinder chambers of the hydraulic cylinder 4 communicate with each other. In an electro-hydraulic actuator for controlling the vibration of vibrating equipment, the limit of its control capability increases as the vibration of the equipment increases due to external disturbances, and exceeds the range of the electro-hydraulic actuator's capability limit diagram. In this case, the hydraulic cylinder 4 can be automatically and functionally separated from the equipment by the action of the oil passage opening/closing valve 8, so this is an improvement that eliminates the problems in the conventionally known electro-hydraulic actuators of this type. The present invention provides a novel electro-hydraulic actuator.

[Brief explanation of the drawing]

FIG. 1 is an overall layout diagram showing one embodiment of the present invention as applied to a seismic isolation device, FIG. 2 is a layout diagram showing the actuator part in a controlled state, and FIG. 4 is a schematic diagram showing an example of a typical conventional electro-hydraulic actuator, and FIG. 5 is a diagram of the limit performance of the hydraulic cylinder. 1
A diagram qualitatively showing an example, FIG. 6, is an oil passage opening/closing valve drive circuit 1
3 is a flowchart showing the function of step 3. 1... Ground (or building), 2... Seismic isolation device, 3...
・Equipment, 4... Hydraulic cylinder, 5... Hydraulic piston, 7... Bypass pipe line, 8... Oil passage opening/closing valve, 9...
...Servo valve, 10...Hydraulic power unit, 11.
...Servo amplifier, 12...Switch, 13...Oil passage opening/closing valve drive circuit, 14...Sensor, 20...Electro-hydraulic actuator. Figure 4 Figure 5 View vJ Satoshi □

Claims (1)

[Scope of Claims] 1. A hydraulic cylinder, a hydraulic piston that is movably attached to the inside of the cylinder and divides the inside of the hydraulic cylinder into two hydraulic cylinder chambers, and pressurized oil in each divided hydraulic cylinder chamber. In order to supply pressure oil, the servo valves are connected to each other via pipes, the hydraulic power unit for supplying pressure oil to the servo valves, and the pipes connecting each hydraulic cylinder chamber of the hydraulic cylinder and the servo valves to each other. It has a bypass pipe connected to the bypass pipe, and an oil passage opening/closing valve for opening and closing the bypass pipeline, and an oil passage opening/closing valve drive circuit and a servo valve for controlling the opening and closing of the oil passage opening/closing valve. The oil passage opening/closing valve drive circuit is connected to a sensor for detecting the position, speed, load pressure of the hydraulic piston, or physical quantities equivalent to these, and further drives the servo valve. 1. An electro-hydraulic actuator, characterized in that the servo amplifier is connected to a switch. 2. The electro-hydraulic actuator according to claim 1, wherein the hydraulic power unit has a hydraulic source and an oil tank for supplying or discharging pressure oil to the servo valve. 3. If each value of the physical quantity detected by the sensor from the hydraulic piston of the hydraulic cylinder is below the respective set value, the position where the bypass circuit is cut off via the oil passage opening/closing valve drive circuit and the oil passage opening/closing valve. The electric power supply according to claim 1 or 2, wherein the bypass circuit is opened via the oil passage opening/closing valve drive circuit and the oil passage opening/closing valve when even one of the set values is exceeded. -Hydraulic actuator.