JP2019190510A - Water pressure direction and flow control valve and its water pressure circuit - Google Patents

Abstract

To provide a water pressure direction and flow control valve using water as working fluid.SOLUTION: A water pressure direction and flow control valve is provided with a housing and a spool constituted by rust-proof material. The housing comprises a first pushing pressure chamber, a second pushing pressure chamber, an input port, a first output port, a second output port and a drain port. The spool has both end parts mounted at the first pushing pressure chamber and the second pushing pressure chamber, and its position is controlled by a normal and inverse rotatable pump connected to the first and second pressing pressure chambers. According to the position, it is possible to communicate between the input port and the first output port or between the input port and the second output port. In addition, a bearing for depressing the spool with working water is installed between the housing and the spool to reduce a friction resistance between the housing and the spool.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a hydraulic pressure / flow rate control valve, and more particularly to a hydraulic pressure / flow rate control valve employing water as a working fluid.

A hydraulic actuator is smaller and lighter than an actuator using an electric motor, and can obtain a large force. In a hydraulic circuit for operating a hydraulic actuator, a switching valve and a control valve are used to control the hydraulic pressure direction and flow rate.
The hydraulic fluid used in such a hydraulic circuit uses oil for reasons such as lubricity and rust prevention, and Patent Document 1 discloses direction switching and flow control for use in a hydraulic circuit. A directional switching valve capable of performing the above is disclosed.

JP-A-11-141696

  In addition to the above-described advantages, the hydraulic actuator has an advantage that it is not affected by electrical noise. Focusing on this point, a new application is conceivable that can be suitably used as a power source for driving an investigation robot, a work robot, or the like that is remotely operated in an environment with a high radiation level such as a nuclear power plant.

However, if oil is used as the hydraulic fluid for hydraulic actuators, if the hydraulic fluid leaks due to the possibility of fire due to abnormally high temperatures, or due to some unforeseen accident or failure, aged deterioration, etc., There is a risk of contamination.
The hydraulic oil is a polymer and contains a large amount of carbon and hydrogen that absorb neutron energy. Oil has a low thermal conductivity, and the molecular structure (characteristics) of the hydraulic oil changes as the temperature rises locally due to the absorbed neutron energy in the path of neutron flight. In some cases, the operating characteristics of the hydraulic circuit May deteriorate.
Furthermore, in the unlikely event that the hydraulic oil is radioactively contaminated, it is necessary to carry out optimal management depending on the substances that make up the hydraulic oil and to store and manage it. In addition, when storing hydraulic oil containing a large amount of carbon with an extremely long half-life of the radioisotope, it is considered that it must be stored semipermanently.

From the above examination, the present inventor has considered that all the above problems can be solved by using water for the hydraulic fluid of the hydraulic actuator. However, it has been found by subsequent experiments that simply changing the hydraulic fluid from oil to water causes various problems such as water friction resistance and rust.
In particular, since water has poor lubricity, friction at the sliding portion increases. As a result, in the switching valve and the control valve, the responsiveness for moving the spool deteriorates, and it becomes difficult to accurately control the flow rate.

In view of the above problems, an object of the present invention is to provide a hydraulic pressure direction / flow rate control valve for use in a hydraulic circuit that uses water instead of oil as hydraulic fluid.
Hereinafter, for the sake of simplicity, the water pressure direction / flow rate control valve may be referred to as a control valve.

The water pressure direction / flow rate control valve according to the present invention is:
The housing includes a housing and a spool. The housing includes a first pressing chamber, a second pressing chamber, an input port (P port), a first output port (A port), and a second output port (B port). ), And a drain port (Dr port),
The spool has a first communication portion, a second communication portion, and a third communication portion,
One end of the spool is located in the first pressing chamber, the other end is located in the second pressing chamber,
The spool is slidably supported in the housing,
The spool depends on the position in the housing,
A state in which the first communication portion communicates the input port and the first output port, and a state in which the third communication portion communicates the drain port and the second output port;
It is possible to select a state in which the first communication portion communicates the input port and the second output port, and the second communication portion communicates the drain port and the first output port. ,
The first press chamber and the second press chamber each have a first pilot port and a second pilot port for introducing working water,
The housing and the spool are formed of a rust resistant material,
The first pilot port and the second pilot port are connected to a control pump that can rotate forward and backward.

The water pressure direction / flow rate control valve according to the present invention is
The spool or housing is made of a rust-resistant material that is ferritic stainless steel, two-phase stainless steel, or water-resistant resin.

By adopting such a configuration, water is used as the working fluid while preventing corrosion (rust) of the casing and the spool, and the direction and flow rate of the working water are controlled (or switched) according to the position of the spool. It is possible to provide a water pressure direction / flow rate control valve capable of performing As a result, it is possible to provide a hydraulic fluid direction / flow rate control valve that can be used even in an environment with a high radiation level such as a nuclear power plant.
In particular, since the pressure of the working water in the first press chamber and the second press chamber is controlled by a control pump capable of forward and reverse rotation, that is, capable of supplying working water in both directions, the first output port is accurate and responsive. And switching of the water pressure direction and flow rate control of the second output port can be performed.

  In addition, since no oil is used as the working fluid, the operation can be performed even in the cooling water of the nuclear reactor. Moreover, since the molecular structure does not change due to radiation unlike oil, the hydraulic pressure direction / flow rate control valve can prevent deterioration of characteristics. In addition, in the unlikely event that water is radioactively contaminated, appropriate treatment can be performed together with the cooling water used in the nuclear reactor. Unlike the case where oil is used as a working fluid, it is not necessary to develop a new treatment method such as decontamination treatment according to the properties of the contaminated substance. In addition, working water does not contain carbon with an extremely long half-life of radioisotopes.

  In particular, the spool can be made of rust-resistant ferritic stainless steel, two-phase stainless steel, or water-resistant resin, so that water can be used for the hydraulic fluid, and further, ferritic stainless steel and two-phase stainless steel can be used for radiation levels. Even in a high environment, it is possible to easily install a detector (for example, a differential transformer) that can detect the position of the spool.

The water pressure direction / flow rate control valve according to the present invention is
A position detector for detecting the position of the spool is provided.

With this configuration, it is possible to control the spool position by measuring the spool position with a position detector and feeding back the measured value of the position to control the control pump. It becomes possible to perform flow control accurately.
It is also possible to control the flow rate of the working water by measuring the flow rate of the water discharged from the control valve.

The water pressure direction / flow rate control valve according to the present invention is
The spool includes a first bearing and a second bearing between the housing and the spool.
The first bearing and the second bearing have grooves communicating with the first pressing chamber and the second pressing chamber, respectively.

  By adopting such a configuration, the first bearing and the second bearing function as bearings that press the spool with the working water, and the first pressing and the second bearing have grooves in the first pressing. Since the working water is supplied from the chamber and the second pressing chamber, friction can be reduced and frictional heat can be effectively discharged.

The water pressure direction / flow rate control valve according to the present invention is
The spool includes a third bearing and a fourth bearing made of a porous material between the housing and the spool.
One end portions of the third bearing and the fourth bearing communicate with the first pressing chamber and the second pressing chamber, respectively.

With such a configuration, the third bearing and the fourth bearing function as a bearing that presses the spool with the working water, and the gap between the porous third bearing and the fourth bearing is the first bearing. Since the working water is supplied from the first pressing chamber and the second pressing chamber, friction can be reduced and frictional heat can be effectively discharged.
Moreover, since it is porous, the third bearing and the fourth bearing do not need to form a groove for flowing the working water, and are easy to manufacture.

ADVANTAGE OF THE INVENTION According to this invention, the water pressure direction and flow control valve used for the hydraulic circuit which employ | adopts water for a hydraulic fluid can be provided. In particular, this direction / flow rate control valve can be suitably used even in an environment with a high radioactivity level such as a nuclear power plant.
Hereinafter, for the sake of simplicity, the “water pressure direction / flow rate control valve” may be simply referred to as “control valve”.

1 is a cross-sectional view of a control valve according to Embodiment 1 and a hydraulic circuit diagram thereof. FIG. 2 is a cross-sectional view showing one operation state of a control valve according to Embodiment 1 and a hydraulic circuit diagram thereof. Sectional drawing of the control valve by Embodiment 2, and the enlarged view of a bearing. FIG. 6 is a top view and a cross-sectional view showing a configuration of a bearing groove according to the second embodiment. Sectional drawing of the control valve by Embodiment 3, and the enlarged view of a bearing. Sectional drawing of a control valve, and the front view of a 1st plate. The enlarged view of the 1st press chamber at the time of using a differential transformer as a position detector.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, none of the following embodiments gives a limited interpretation in the recognition of the gist of the present invention. The same or similar members are denoted by the same reference numerals, and the description thereof may be omitted.

(Embodiment 1)
FIG. 1 shows a cross-sectional view of a control valve 1 (hydraulic pressure direction / flow rate control valve) according to Embodiment 1 of the present invention and a hydraulic circuit diagram including the control valve 1.
Both ends of the spool 3 installed in the liquid-tight housing 2 are pressed by a first spring 6 and a second spring 7 provided in the first pressing chamber 4 and the second pressing chamber 5. . The cross section of the spool 3 is preferably formed in a circular shape, but is not limited thereto.

  The first spring 6 and the second spring 7 are springs having the same elastic force, so that the spool 3 can be positioned in the center, but can also be configured by springs having different elastic forces. is there.

The housing 2 is provided with a first pilot port 8 and a second pilot port 9 that communicate with the first pressing chamber 4 and the second pressing chamber 5, respectively.
Water (working water) that is a working fluid can be introduced from the first port 8 or the second port 9 and each end of the spool 3 can be pressed by the working water.

  The spool 3 includes a first support part 63 and a second support part 64, and the first support part 63 and the second support part 64 are slidably in contact with the housing 2. However, in order to reduce the frictional resistance, there is an air gap that can form a water film between the first support portion 63 and the second support portion 64 and the housing 2. Since the kinematic viscosity coefficient of water is as small as about 1/30 that of oil and easily leaks, the gap between the spool 3 and the housing 2 is preferably 1 to 15 μm.

The spool 3 is moved relative to the housing 2 so that the spool 3 can be moved against the urging force of the first spring 6 and the second spring 7 due to the hydraulic pressure difference applied to both ends of the spool 3. Are slidably installed.
As will be described later, it is possible to determine and control the position of the spool 3 only by the pressing force of the working water against the both ends of the spool 3 without using the first spring 6 and the second spring 7.

The housing 2 includes a P port 10 that is an input port, an A port 11 that is a first output port, a B port 12 that is a second output port, and a drain port 13, and the P port 10 is connected to the A port 11 and the B port. Located between port 12.
The position of the spool 3 can be controlled by adjusting the hydraulic pressure of the working water introduced into the first pilot port 8 or the second pilot port 9.
Depending on the position of the spool 3, the input port 10 and the first output port 11 communicate with each other, and the drain port 13 and the second output port 12 communicate with each other, or the input port 10 and the second output port 12 can be selected, and a state in which the drain port 13 and the first output port 11 communicate with each other can be selected.

  In FIG. 1, the housing 2 is integrally formed. However, in order to install the spool 3, the first spring 6, and the second spring 7 in the housing 2, a dotted line in FIG. As shown by being divided, it can be composed of a central portion where the spool 3 is installed and two end portions where the first spring 4 and the second spring 5 are installed. After the spool 3, the first spring 4 and the second spring 5 are installed in the center portion, both ends and the center portion are liquid-tightly connected to form the housing 2.

Since water contacts the casing 2, the spool 3, the first spring 6, and the second spring 7, for example, brass or stainless steel having corrosion resistance is used. As the stainless steel, austenitic stainless steel having particularly excellent corrosion resistance can be used. In addition, ferritic stainless steel having a high thermal conductivity and a low thermal expansion coefficient as compared with austenitic stainless steel can be suitably used. For the spool 3, ferritic stainless steel having ferromagnetism can be suitably used for the purpose described later. Furthermore, duplex stainless steel, which is a two-phase mixture of austenite and ferrite, can be suitably used for the spool 3.
In addition, since it is possible to fasten and use the separated sensor portion, a water-resistant resin may be used as another rust-resistant material instead of stainless steel suitable as a material for the spool or the housing.

  It is also possible to use brass as the housing 2. By using a material having a higher coefficient of thermal expansion than the spool 3 as the material of the housing 2 that supports the spool 3 so as to cover the spool 3, even if the housing 2 and the spool 3 are thermally expanded due to an increase in temperature, the sliding of the spool 3 A decrease in mobility can be prevented. Therefore, it is preferable to use stainless steel for the spool 3 and use brass (having a higher thermal expansion coefficient than stainless steel) for the casing 2. Furthermore, the thermal conductivity of brass is higher than that of stainless steel, and has the effect of alleviating uneven temperature of the control valve 1. In particular, for the purpose of use in a high-temperature environment like a nuclear power plant, it is necessary to have the above-described material configuration in consideration of the influence of temperature.

A first pilot passage 14 and a second pilot passage 15 are connected to the first pilot port 8 and the second pilot port 9, respectively. The first pilot passage 14 and the second pilot passage 15 are connected to a water supply / drain port of a control pump 16 capable of forward and reverse rotation.
The control pump 16 capable of forward / reverse rotation can select the forward rotation direction and the reverse rotation direction with respect to the rotation direction of the drive source, can switch the flow direction of the liquid bidirectionally, and can control the flow rate (and pressure).
The control pump 16 is operated to the first pilot passage 14 or the second pilot passage 15 using a servo motor or a stepping motor whose rotation direction and number of rotations can be controlled by an arithmetic processing unit such as a microcomputer (not shown), for example. Send water. By controlling the control pump 16 by the arithmetic processing unit, the pressure of the working water introduced into the first pilot port 8 and the second pilot port 9 can be controlled.

In this way, by using the control pump 16 capable of forward and reverse rotation, the working water is directed from the first pilot port 8 to the second pilot port 9 or from the second pilot port 9 to the first pilot port 8. The flow can be selected and the working water can flow in both directions.
For example, when operating water flows from the second pilot port 9 toward the first pilot port 8 by the control pump 16, the first pressing chamber 4 is pressurized by the operating water and the second pressing chamber 5 is depressurized. The
When the control pump 16 is reversed (or when the motor that is the power source of the control pump 16 is reversed), the first pressing chamber 4 is depressurized by the working water, and the second pressing chamber 5 is pressurized. The Further, the pressure in the first pressing chamber 4 and the second pressing chamber 5 can be controlled by the flow rate of the working water by the control pump 16. Further, the pressure is controlled by the substantially closed circuit of the first pressing chamber 4, the control pump 16, and the second pressing chamber 5 instead of the configuration in which the hydraulic fluid is returned to the tank as in the literature 1. Thus, the spool 3 can be moved in both directions and the moving distance can be controlled.
The substantially closed circuit means that the first pressing chamber 4, the control pump, except for a part of the working water flowing out to the drain port 13 side at the sliding portion between the spool 3 and the housing 2. 16 and the circuit where the working water is closed by the second pressing chamber 5.
Further, as will be described later, the flow rate of the working water discharged from the first output port 11 and the second output port 12 can be controlled depending on the moving distance of the spool 3. As a result, the control valve 1 can be driven by the water pressure circuit in which the control pump 16 is connected to the control valve 1 to function as a direction and flow control valve.

Further, as shown in FIG. 1, a low pressure priority type shuttle valve 33 is installed in the water pressure circuit. If a predetermined pressure difference is generated between the passage (one of the first pilot passage 14 or the second pilot passage 15) depressurized by the control pump 16 and the drain passage 24 (or the tank 26), the drain The working water flows from the passage 24 to the decompressed passage and is replenished to the substantially closed circuit of the first pressing chamber 4, the control pump 16, and the second pressing chamber 5. Yes. Thus, by using the shuttle valve 33, the pressure control of the first pressing chamber 4 and the second pressing chamber 5 can be stably performed. The shuttle valve 33 also has an effect of preventing malfunction of the control valve 1 due to the occurrence of cavitation.
In this case, the pressure of the working water in the tank 26 connected to the drain passage 24 is kept constant. For example, the pressure of the working water can be maintained at atmospheric pressure by bringing the level of the working water in contact with the atmosphere in the tank 26, but an accumulator is connected instead of contacting the level of the working water in the tank 26 with the atmosphere. You may hold | maintain the pressure of the working water in 26 constant (for example, 1 atmosphere etc.).
The shuttle valve 33 may be composed of two check valves as shown in the circuit diagram of FIG.

In addition, when two electromagnetic valves are used like literature 1, it is necessary to control two electromagnetic valves synchronously, However Since the said control valve 1 does not use an electromagnetic valve, control is easy.
Further, when water is used as the hydraulic fluid, the lubricity is inferior compared to oil and friction increases. Therefore, the method of controlling with a solenoid valve as in Document 1 lacks the driving force of the solenoid valve. The valve movement is not smooth, the responsiveness is further deteriorated, and it is difficult to control the two solenoid valves in synchronization. Therefore, pressure control cannot be performed with high accuracy.
However, by using one control pump 16 capable of forward and reverse rotation, the pressures in both the first pressing chamber 4 and the second pressing chamber 5 can be controlled simultaneously and synchronously. Further, a sufficient driving force for moving the spool 3 can be obtained.
Further, since the pressure difference between the first pressing chamber 4 and the second pressing chamber 5 can be directly controlled and the spool 3 is moved by the pressure difference, the spool positioning spring and the pressure of the hydraulic fluid are used as in Reference 1. There is no need to control the balance, and the movement (position) of the spool 3 can be controlled without using a spring.
Further, since the total volume of the working water in the first pressing chamber 4 and the second pressing chamber 5 is constant and is a closed circuit as described above, the first pressing chamber 4 and the second pressing chamber 4 are controlled by the control pump 16. It is also possible to control the movement (position) of the spool 3 by controlling the total flow rate of the working water that moves from one of the pressing chambers 5 to the other. The total flow rate can be detected by time integration by installing a flow meter at the water supply / drain port of the control pump 16, but can also be detected by the number of rotations of the motor of the control pump 16.

Hereinafter, the operation of the control valve 1 will be described in more detail.
As described above, the urging force is applied to both ends of the spool 3 by the first spring 6 and the second spring 7. A difference in water pressure between the first pressing chamber 4 and the second pressing chamber 5 is applied to both ends of the spool 3 by the working water introduced into the first pilot port 8 and the second pilot port 9. When it becomes higher than the biasing force, the spool 3 moves. The moving amount and moving direction of the spool 3 can be controlled by the pressure of the working water introduced into the first pilot port 8 and the second pilot port 9. For example, when the water pressure on the first pressing chamber 4 side is high, the spool 3 moves to the second pressing chamber 5 side. The urging force of the second spring 7 increases according to Hooke's law, and the spool 3 moves to a position where the pressure difference of the working water and the urging force of the second spring 7 are balanced. Therefore, since the pressure difference applied to both ends of the spool 3 can be controlled by controlling the working water introduced into the first pilot port 8 and the second pilot port 9 by the control pump 16, the moving direction of the spool 3 and The amount of movement can be easily controlled.

As shown in FIG. 1, the first spring 6 and the second spring 7 apply a biasing force to the spool 3 via the first plate 31 and the second plate 32. The second plate 32 may be omitted, and the urging force may be applied by directly contacting the spool 3.
By installing the first plate 31 and the second plate 32, the first spring 6 and the second spring 7 and the spool 3 are prevented from being damaged from each other by friction, and the first spring 6 and It is also possible to transmit the biasing force of the second spring 7 to the spool 3 evenly.
The first plate 31 and the second plate 32 can be made of a material having a lower hardness than the first spring 6, the second spring 7 and the spool 3, and may be replaced periodically.
The spool 3 slides with respect to the first plate 31 and the second plate 32 (see FIG. 2).

  As shown in FIG. 1, the spool 3 has a first valve body 61 and a second valve body 62, and these valve bodies function as valves of the valve. The first valve body 61 and the second valve body 62 close the first output port 11 and the second output port 12 in a state where the spool 3 is located in the center, and the input port 10 It does not communicate with either the output port 11 or the second output port 12.

The spool 3 includes a first recess 27 between the first valve body 61 and the second valve body 62. As the spool 3 moves, the input port 10 communicates with the first output port 11 or the second output port 12 via the first recess 27.
Further, the spool 3 includes the second recess 28 and the second support portion between the first valve body 61 and the first support portion 63 and between the second valve body 62 and the second support portion 64, respectively. 3 recesses 29 are provided. As the spool 3 moves, the first output port 11 and the second output port 12 communicate with the drain port 13 via the second recess 28 and the third recess 29.
The first, second, and third recesses 27, 28, and 29 function as first, second, and third communication portions that communicate between the ports, respectively.

For example, when the spool 3 moves to the second pressing chamber 5 side, the first recess 27 communicates with the input port 10 and the second output port 12, and the second recess 28 connects with the first output port 11 and the drain. It communicates with port 13. As a result, the first recess 27 and the second recess 28 function as flow paths, the input port 10 and the second output port 12 communicate, and the first output port 11 and the drain port 13 communicate. .
Further, when the spool 3 moves to the first pressing chamber 4 side, the first recess 27 communicates with the input port 10 and the first output port 11, and the third recess 29 becomes the second output port 12 and the inside. It communicates with the passage 30. Since the internal passage 30 is connected to the drain port 13, the first concave portion 27 and the second concave portion 28 function as flow paths, the input port 10 and the first output port 11 communicate with each other, and the second The output port 12 and the drain port 13 communicate with each other.
In the second recess 28, the inner diameter of the housing 2 is larger than the outer diameter of the spool 3, so the internal passage 30 is connected to the drain port 13 as described above.

The working water sent to the input port 10 by the main pump 18 is discharged from the first output port 11 or the second output port 12 according to the position of the spool 3.
The main pump 18 communicates with a tank (not shown), and working water is supplied from the tank.

When the spool 3 is located at the center, the working water is not sent to either the first output port 11 or the second output port 12. When the spool 3 moves to the second pressing chamber 5 side, the opening area between the first recess 27 and the input port 10 and the first recess 27 and the second output port 12 depend on the moving distance. Since the opening area is changed, the flow rate of water discharged from the second output port 12 is changed by changing the conductance of the working water between the input port 10 and the second output port 12. Similarly, when the spool 3 moves to the first pressing chamber 4 side, the opening area of the first recess 27 and the input port 10 and the first recess 27 and the first output port depend on the moving distance. Therefore, the flow rate of water discharged from the first output port 11 is changed by changing the conductance of the working water between the input port 10 and the first output port 11.
FIG. 2 shows, as an example, a specific state in which the spool 3 is moving toward the first pressing chamber 4 (in the direction of the arrow). As the opening degree at A and B indicated by circles in the figure changes according to the amount of movement of the spool 3, the conductance for the working water changes. The same applies when the spool 3 moves to the second pressing chamber 5 side.

Therefore, by controlling the position of the spool 3, it is possible to switch to the first output port 11 or the second output port 12 of the working water sent to the input port 10, and the first output port 11 Alternatively, the flow rate of the working water discharged from the second output port 12 can be controlled. Further, the position of the spool 3 can be controlled by the hydraulic pressure of the working water sent to the first pressing chamber 4 and the second pressing chamber 5 using the control pump 16. By using the servo motor as the power source of the control pump 16 as described above, the pressure of the working water can be accurately controlled.
Note that a flow meter is provided in the first output port 11 or the second output port 12, the flow rate of the working water discharged from the first output port 11 or the second output port 12 is measured, and the measured value of the flow rate is The control pump 16 may be controlled by a PID control method or the like using an arithmetic processing unit such as a microcomputer so that the predetermined flow rate is obtained.

Note that the position detector 100 for detecting the position of the spool 3 may be installed, and the detected position may be fed back to control the control pump 16.
That is, for example, the rotation direction and the number of rotations of a servo motor that is a drive source of the control pump 16 can be controlled so that the actual measurement value detected by the position detector 100 is equal to the desired position of the spool 3. For example, PID control can be employed as a method for feedback control based on the actually measured value of the detected position using an arithmetic processing unit such as a microcomputer (not shown), but is not limited thereto. Because it is a servo motor control, unlike the control of the solenoid valve of Document 1, precise control (with high spatial resolution) is possible. Further, unlike the control using a pressure gauge as in Document 1, the position of the spool 3 is directly detected, so that accurate control is possible. Further, unlike the literature 1, the position of the spool 3 can be controlled regardless of the spring constant of the spring (Hooke's law).
As will be described later, since the arithmetic processing unit such as a microcomputer and the control pump 16 can be installed in an environment with a low radioactivity level, an arithmetic processing unit such as a microcomputer can be used.

As the position detector 100, a device that electrically and magnetically detects the amount of movement of the spool 3 can be used, but is not limited thereto. Although a mechanical method may be adopted as the detection method, since the control pump 16 is controlled by the detected position, any method can be used as long as an actual measurement value of the position can be output to the outside.
The position detector 100 is not limited to the first pressing chamber 4 and can be attached to the second pressing chamber 5 or the like, and the attachment location is not limited to these.

  In particular, in an environment where the radiation level is high, a differential transformer that is not easily affected by noise due to radiation can be suitably used as the position detector. In particular, by using ferritic stainless steel as the material of the spool 3, a differential transformer type position detecting device can be suitably used. That is, since the spool 3 is made of ferritic stainless steel having ferromagnetism, the moving spool 3 itself functions as an iron core that changes the mutual conductance of the differential transformer, so that only the coil of the differential transformer is the first. By installing them on the inner walls of the pressing chamber 4 and the second pressing chamber 5, the position detector 100 can be easily configured, and the operation of the spool 3 is not affected. Furthermore, since the coil itself has a simple structure in which an electric wire is wound, it is not affected by water pressure, and the position detection value fluctuates due to pressure fluctuations in the first pressing chamber 4 and the second pressing chamber 5. There is nothing.

FIG. 7A shows an enlarged view of the first pressing chamber 4 when a differential transformer is used as the position detector 100. In this example, the position detector 100 is attached to the expansion chamber 34 provided in the moving direction of the spool 3 (leftward in FIG. 7A).
The differential transformer is composed of a primary coil 100a and two secondary coils 100b and 100c, and the two secondary coils 100b and 100c are differentially connected to each other. When an AC voltage is applied to the primary coil 100a, a voltage is induced in the secondary coils 100b and 100c by electromagnetic induction.
As shown in FIG. 7A, the spool 3 is connected with a magnetic response body 35 made of, for example, a ferromagnetic stainless steel or a two-phase stainless steel. The expansion chamber 34 communicates with the first pressing chamber 4 through the opening 36, and the magnetic response body 35 can move through the opening 36.
When the spool 3 moves, the magnetic responder 35 also moves, so that the mutual inductance between the primary coil 100a and the two secondary coils 100b and 100c changes depending on the position of the magnetic responder 35. As a result, the two two The voltage induced in the secondary coils 100b and 100c changes. The position of the spool 3 can be detected from the difference between the voltages induced in the two secondary coils 100b and 100c.
Further, since the secondary coils 100b and 100c are differentially connected, even if noise occurs, they cancel each other, so that noise resistance is high. In addition, since the magnetic response body 35 and the spool 3 can be integrally formed by configuring the spool 3 itself with ferritic stainless steel or two-phase stainless steel, a manufacturing advantage can be obtained.
Further, the opening 36 may be sealed with an O-ring or the like to prevent the working water from entering the expansion chamber 34 and improve the rust preventive action of the coil of the differential transformer and the magnetic response body 35.
Further, since the position detector 100 is installed in the expansion chamber 34, the first spring 6 is not interposed between the position detector 100 and the magnetic response body 35. As a result, it is not affected by the fluctuation of the magnetic field by the first spring 6, and the distance between the position detector 100 and the magnetic response body 35 can be set freely without interfering with the first spring 6. can do.
Further, as shown in FIG. 7B, the position detector 100 may be installed as a configuration not using the first spring 6 (see, for example, FIG. 3). In this case, the apparatus can be downsized as compared with the configuration shown in FIG. Note that the magnetic responder 35 and the spool 3 can be integrally formed of the spool 3 itself of ferritic stainless steel or two-phase stainless steel.
The configuration of the differential transformer is not limited to the differential transformer shown in FIG. 7, and a known differential transformer can be used.
Further, the position detector 100 may be installed in either the first pressing chamber 4 or the second pressing chamber 5.

  The working water flowing through the hydraulic circuit is replenished from the tank 26.

Hereinafter, a method for controlling the actuator 20 by a hydraulic circuit using the control valve 1 will be described.
In the hydraulic circuit shown in FIG. 1, one end of the input passage 17 communicates with the input port 10 and the other end communicates with the main pump 18.
One end of the first output passage 19 communicates with the first output port 11, and the other end communicates with an actuator 20, for example, a first pressure chamber 21 of a cylinder.
One end of the second output passage 22 communicates with the second output port 12, and the other end communicates with the second pressure chamber 23 of the cylinder that is the actuator 20.
The drain port 13 communicates with the drain passage 24, and the drain passage 24 communicates with the tank 26.

The actuator 20 is operated by the working water introduced into the first pressure chamber 21 and the second pressure chamber 23, and for example, the piston 25 can be moved. The flow direction of the working water introduced into the first pressure chamber 21 and the second pressure chamber 23 is controlled by the position of the spool 3, and due to the pressure difference between the first pressure chamber 21 and the second pressure chamber 23, The moving direction of the piston 25 can be controlled. Further, the stress exerted from the piston 25 can be controlled.
The actuator 20 is not limited to a cylinder, and may be a hydraulic drive motor. In this case, the rotation direction of the motor is switched depending on the flow direction of the working water. Further, the rotational speed can also be controlled in accordance with the hydraulic pressure difference of the working water.
Thus, by using the control valve 1 and controlling the flow direction and flow rate of the hydraulic fluid, the movement direction and output (stress, rotation speed, etc.) of the actuator 20 can be controlled.

As described above, the control valve 1 is configured to be usable in a high radiation level environment (including the position detector 100). Therefore, it is possible to mount the control valve 1 together with the actuator 20 on the robot used in the nuclear decommissioning work. By installing the control valve 1 in the vicinity of the actuator 20, the response performance of the robot operation can be improved. Can be improved.
On the other hand, since the control valve 1 and the actuator 20 are driven by the working water, the main pump 18, the control pump 16, and an arithmetic processing unit such as a microcomputer for controlling motors of these pumps should be isolated in an environment with a low radiation level. It is possible to install. The tank 26 can also be installed in an environment with a low radiation level, and the level of the working water in the tank 26 can be in contact with the atmosphere.

  Further, the water pressure circuit may be provided with a brake valve 37 for the purpose of preventing abnormal high pressure of working water and preventing cavitation.

In the above-described embodiment, the spool 3 has a configuration in which an urging force is applied to both ends by the first spring 6 and the second spring 7. As described above, the first spring 6 and the second spring 3 are configured as described above. The spool 7 may be moved only by the pressure difference of the working water introduced into the first pressing chamber 4 and the second pressing chamber 5 without using the spring 7.
When the first spring 6 and the second spring 7 are used, the spool 3 can be quickly moved to the center portion, and the switching speed between the first output port 11 and the second output port 12 is increased. Although the response speed as a switching valve can be improved, when the spool 3 is moved only by the pressure difference of the working water between the first pressing chamber 4 and the second pressing chamber 5, the movement of the spool 3 The amount can be accurately controlled, and the performance (flow rate accuracy) as a flow rate control valve is improved.

(Embodiment 2)
FIG. 3A is a cross-sectional view of the control valve 1 according to the second embodiment of the present invention. For simplicity, a water pressure circuit connected to the control valve 1 is omitted, but a water pressure circuit similar to FIG. 1 is connected.
For supporting the spool 3 between the first support portion 63 and the second support portion 64 of the spool 3 and the housing 2 on the side of the first press chamber 4 and the second press chamber 5 of the spool 3. A first bearing 41 and a second bearing 42 are provided. Even when water having poor lubricity is used, it is possible to further improve the switching speed and flow rate control by reducing the friction between the spool 3 and the housing 2.
In the second embodiment, an example in which the first spring 6 and the second spring 7 are not used in the first pressing chamber 4 and the second pressing chamber 5 is shown. A spring 6 and a second spring 7 may be provided. The same applies to the other embodiments.

FIG. 3B is an enlarged view showing the structure of the first bearing 41 and the second bearing 42 as viewed from the spool 3 side, and FIG. 3C is a cross-sectional view taken along line AA ′ of FIG. It is a cross section.
The first bearing 41 and the second bearing 42 have, for example, a cylindrical shape. As shown in FIG. 3B, the first bearing 41 and the second bearing 42 include one or more grooves 43, and the grooves One end side of 43 has an inflow port of working water on the first pressing chamber 4 and the second pressing chamber 5 side so as to communicate with at least the first pressing chamber 4 and the second pressing chamber 5, respectively. That is, the working water introduced into the first pressing chamber 4 and the second pressing chamber 5 flows into the grooves 43 formed in the first bearing 41 and the second bearing 42.

  As shown in FIG. 3C, the open portion of the groove 43 faces the spool 3 side, and the working water that has flowed into the groove 43 presses the surface of the spool 3. As a result, working water enters between the spool 3 and the first bearing 41 and the second bearing 42 to form a water film, reducing friction between the spool 3 and the first bearing 41 and the second bearing 42. To do.

The groove 43 can be installed in a spiral shape on the inner wall surfaces (surfaces on the spool 3 side) of the first bearing 41 and the second bearing 42, for example.
Further, the other end of the groove 43 formed in the first bearing 41 and the second bearing 42 may be provided with an opening so as to communicate with the second recess 28 and the third recess 29 of the spool 3. Good.

By flowing the working water from the first pressing chamber 4 and the second pressing chamber 5 to the second concave portion 28 and the third concave portion 29, respectively, the amount of working water to be used is increased. The frictional heat between the first bearing 41 and the second bearing 42 can be dissipated. As a result, the temperature rise of the control valve 1 can be effectively prevented, and the characteristic change of the control valve 1 accompanying the temperature change can be prevented.
The control pump 16 is configured to flow the working water in both directions. For example, when the first pressing chamber 4 is pressurized, the second pressing chamber 5 is depressurized. In the groove 43 of the second bearing 42 communicating with the decompressed second pressing chamber 5, the working water flows from the third recess 29 side to the second pressing chamber 5. In this case, the working water is replenished from the tank 26 via the drain passage 24 and the internal passage 30. On the other hand, when the second pressing chamber 5 is pressurized, the working water flows into the first pressing chamber 4 from the second recess 28 side in the groove 43 of the first bearing 41.
Therefore, the tank 26 is filled with working water from the drain passage 24 and the internal passage 30.

  When water is used as the hydraulic fluid, the boiling point is lower than that of oil. Therefore, if the control valve 1 is operated frequently, the hydraulic water is vaporized by friction and may cause malfunction. However, vaporization of the working water can be prevented by dissipating the frictional heat. This is particularly effective when used in a place where the working environment temperature is high, such as a nuclear power plant. Moreover, even if the temperature rises locally due to radiation, it is possible to diffuse heat quickly.

FIG. 4A shows a modification of the shape of the groove 43. Hereinafter, the groove 43 formed in the first bearing 41 will be described, but the same applies to the groove 43 formed in the second bearing 42.
The groove 43 has an opening at least on the first pressing chamber 4 side and communicates with the first pressing chamber 4.

  Compared with the shape of the groove 43 shown in FIG. 3B, FIG. 4A has a shape in which the direction in which the working water flows is greatly changed. That is, the P side in FIG. 4A is the first pressing chamber 4 side (or the second pressing chamber 5 side), and the Q side is the second recess 28 side (or the third recess 29 side). The direction perpendicular to the direction from the P side to the Q side is the Z direction, the arrow direction is the plus direction, and the opposite direction is the minus direction. The Z direction component of the flow rate of the working water flowing along the groove 43 from the P side to the Q side is where the direction of the direction is reversed because the groove 43 meanders (for example, g1 and g2 in FIG. 4A). , G3, etc.).

FIG. 4B shows a PQ cross-sectional view of the first bearing 41, and the state of the working water flow in the groove 43 is indicated by an arrow.
As shown in FIG. 4B, the flow of the working water from P to Q is blocked by the side wall of the groove 43 at g1, g3, etc., and a part of the working water is placed on the side wall of the groove 43. Along the spool 3 side (upward in the figure), presses the surface of the spool 3, and then flows along the interface between the spool 3 and the first bearing 41. (Refer to the arrow in FIG. 4B.) When the working water presses the surface of the spool 3, the spool 3, the first bearing 41, and the frictional resistance are reduced. As a result, the frictional force that the spool 3 slides in the direction along PQ while being in contact with the surface of the first bearing 41 is reduced.

  As described above, the groove 43 has a portion that changes (reverses) the direction of the component of the flow of the working water in the direction perpendicular to the sliding direction of the spool 3, for example, so that the working water flowing in the groove 43 flows. The spool 3 can be effectively pressed at the location where the direction of the direction is changed.

In addition, the shape of the groove | channel 43 is not limited to Fig.4 (a), For example, a shape as shown in FIG.4 (c) may be sufficient.
Further, as shown in FIG. 4C, the groove 43 includes a first opening 44 at one end to communicate with the first pressing chamber 4, and the other end communicates with the second recess 28. For this purpose, a second opening 45 is provided.
As described above, frictional heat between the spool 3 and the first bearing 41 is generated by communicating one end of the groove 43 with the first pressing chamber 4 and communicating the other end with the second recess 28. It is possible to quickly diverge (discharge), and by preventing the control valve 1 from rising in temperature, fluctuations in the characteristics of the control valve 1 can be prevented.

  Moreover, as shown in FIG.4 (d), the cross-sectional shape of the side wall of the groove | channel 43 is good also as a taper shape. If the wall that blocks the water flow is vertical, some of the water will be reversed and vortices are likely to occur, which may hinder the water flow. By making the side wall of the groove 43 into a tapered shape, the flow of working water along the groove 43 for pressing the spool 3 becomes smooth, and the friction between the spool 3 and the first bearing 41 is more effective. Can be reduced.

Thus, the pressing force of the working water against the spool 3 can be controlled and adjusted by the structure of the groove 43.
Although the first bearing 41 has been described as an example, the same applies to the second bearing 42.

Moreover, the material which comprises the 1st bearing 41 and the 2nd bearing 42 can use brass, stainless steel, a ceramic, and resin with rust resistance. Even if the material has a low thermal conductivity, the working water is caused to flow from the first pressing chamber 4 side (or the second pressing chamber 5 side) as described above, and the second recess 28 side (or the third pressing chamber 5 side). By adopting a configuration in which the gas flows out from the concave portion 29 side, frictional heat can be effectively dissipated.
Therefore, even in a situation where the external environment temperature is high, it is possible to use water as the working fluid while preventing corrosion (rust) of the control valve 1.
However, it is necessary to consider the change in the gap due to the difference in thermal expansion between the material constituting the first bearing 41 and the second bearing 42 and the spool 3. That is, it is necessary to provide the gap (preferably 1 to 15 μm) between the first bearing 41 and the second bearing 42 and the spool 3 within the operating temperature range.

In the switching method using a solenoid valve as in Document 1, the friction of the solenoid valve cannot be reduced by using bearings such as the first bearing 41 and the second bearing 42 described above. However, since the control valve 1 according to the present invention directly controls the pressure difference between the first pressing chamber 4 and the second pressing chamber 5 using the control pump 16, the first bearing 41 and the second bearing The working water can be supplied to 42 to effectively reduce the friction.
As described above, in the third embodiment, the pressure control using the control pump 16 can effectively reduce the friction between the spool 3 and the housing 2.

(Embodiment 3)
In Embodiment 2, the 1st bearing 41 and the 2nd bearing 42 which have the groove | channel 43 were used as a bearing which presses and supports the spool 3 with working water. In this embodiment, in order to press and support the spool 3 with working water, as shown in FIG. 5A, it is installed between the first support portion 63 and the second support portion 64 and the housing 2. As the bearings to be used, a third bearing 47 and a fourth bearing 48 made of a porous material are used.
One end portions of the third bearing 47 and the fourth bearing 48 communicate with the first pressing chamber 4 and the second pressing chamber 5, respectively.
Therefore, working water is supplied from the first pressing chamber 4 and the second pressing chamber 5 to the third bearing 47 and the fourth bearing 48. Further, the other end portions of the third bearing 47 and the fourth bearing 48 communicate with the drain port 13, and frictional heat can be dissipated by the working water.
In FIG. 5A, for simplicity, a water pressure circuit connected to the control valve 1 is omitted, but a water pressure circuit similar to that in FIG. 1 is connected.

FIG. 5B shows a sectional view of the third bearing 47. Hereinafter, the effect of the bearing made of the porous material will be described using the third bearing 47 as an example, but the same applies to the fourth bearing 48.
As shown in FIG. 5B, the porous material has a solid portion 49 and a void portion 50 made of a substance constituting the porous material. The working water flows in various directions through the gap 50 and spreads into the third bearing 47, and the working water flows from the first pressing chamber 4 to the second recess 28 side.

  The working water flows in the gap 50 and is blocked by the solid portion 49, and the flow direction is changed. A part of the working water whose flow direction is changed by the solid portion 49 flows to the surface side of the spool 3. As a result, part of the working water flowing from the first pressing chamber 4 toward the second recess 28 presses the spool 3 and reduces friction between the spool 3 and the third bearing 47.

When a porous material is used for the fourth bearing 48, the working water flows from the second pressing chamber 5 to the third concave portion 29, so that the working water presses the spool 3 and reduces friction. .
Further, the third bearing 47 and the fourth bearing 48 of the third embodiment use the gap 50 instead of the groove 43 as the flow path of the working water, and thus the first bearing 41 of the second embodiment. However, the third bearing 47 and the fourth bearing 42 are different from the second bearing 42 in the same manner as the first bearing 41 and the second bearing 42 in the second embodiment by changing the flow direction of the working water by the control pump 16. The direction of the working water flowing through the bearing 48 changes.

Porous materials can be sintered granular alloys, metal nitrides, metal oxides, metal oxynitrides (including silicon as metal), ceramics and resins, select rust resistant materials can do.
By using the porous material, the friction with which the spool 3 slides can be reduced without performing the groove processing as in the second embodiment.
Further, the pressing force on the spool 3 can be controlled by changing the porosity of the porous material.

Further, the first plate 31 and the second plate 32 provided with openings are used, and the working water flowing to the first bearing 41 and the second bearing 42 or the third bearing 47 and the fourth bearing 48 is used. It is also possible to adjust the water flow and flow rate.
In the case of the first bearing 41 and the second bearing 42, the amount of flowing working water and the flowing region can be controlled by the shape of the groove 43. In the case of the third bearing 47 and the fourth bearing 48, the amount of flowing working water can be controlled by the porosity of the porous material, but it is difficult to control the region through which the working water flows by the porosity. However, by using the first plate 31 and the second plate 32, it is possible to control the region where the working water flows to the third bearing 47 and the fourth bearing 48. Thereby, for example, it is possible to control the friction in consideration of the weight of the spool 3.

FIG. 6A is a cross-sectional view showing an example in which the first plate 31 and the second plate 32 having openings are applied to the first bearing 41 and the second bearing 42. The same applies when applied to the third bearing 47 and the fourth bearing 48.
For simplicity, a water pressure circuit connected to the control valve 1 is omitted, but a water pressure circuit similar to FIG. 1 is connected.
Moreover, you may provide the 1st spring 6 and the 2nd spring 7 as shown in FIG.
6B shows a front view (front view seen from the first pressing chamber 4 side) of the first plate 31 as an example, but the second plate 32 is the same.

As shown in FIG. 6B, the first plate 31 has an opening 51. The opening 51 communicates with the first pressing chamber 4 and the groove 43 of the first bearing 41 or the third bearing 47 made of a porous material, and the working water is supplied to the groove 43 of the first bearing 41. Or, it flows into the third bearing 47.
By adjusting the area, number, and arrangement of the openings 51, the flow rate of the working water can be adjusted.
Moreover, the distribution of the flow rate of the working water can be adjusted by adjusting the area, number, and arrangement of the openings 51. For example, the area of the opening 51 on the side to which the weight of the spool 3 is applied can be set larger than the others so that the hydraulic pressure of the working water is increased.

  Moreover, in each said embodiment, the cross section of the spool 3 is not limited circularly.

  In this way, the amount of working water supplied to the first bearing 41 and the second bearing 42 or the third bearing 47 and the fourth bearing 48 is adjusted by the first plate 31 and the second plate 32. As a result, the degree of freedom in adjusting the pressing force on the spool 3 can be increased.

In FIG. 6A, the first plate 31 and the second plate 32 are in contact with the spool 3, but the cross-sectional shapes of the first plate 31 and the second plate 32 are, for example, The first plate 31 and the second bearing 42 are the same shape as the first bearing 41 and the second bearing 42 or the third bearing 47 and the fourth bearing 48. It is good also as a structure which the plate 32 does not move but always contacts the first bearing 41 and the second bearing 42 or the third bearing 47 and the fourth bearing 48.
As a result, the amount of working water to the first bearing 41 and the second bearing 42 or the third bearing 47 and the fourth bearing 48 can be adjusted more effectively.

As described above in Embodiments 2 and 3, by using the first bearing 41, the second bearing 42, the third bearing 47, and the fourth bearing 48, the spool 3 is pressed by the working water. Thus, friction during sliding can be reduced, and the pressing force on the spool 3 can be controlled (and adjusted).
Therefore, by controlling the flow rate of the working water and the frequency (speed) of the flow direction with the control pump 16, it is also suitable for low speed operation that is easily affected by friction, for example, 5 mm / sec or less. Can be used. Further, even under a high temperature environment, the water pressures of the first bearing 41, the second bearing 42, the third bearing 47, and the fourth bearing 48 can be adjusted according to the environment, and can be suitably used.

  In addition, although the control valve 1 which concerns on this invention can be used conveniently also in a nuclear power plant, it cannot be overemphasized that it can apply also in the other use.

  Moreover, although the control valve 1 which concerns on this invention can control the direction and flow volume of working water, it cannot be overemphasized that it can be used as a switching valve which switches the flow direction of working water, or a flow control valve which only controls a flow rate.

  According to the present invention, it is possible to provide a control valve that uses water as a working fluid that is suitable for use in a nuclear power plant or the like, and the control valve can be used widely without being limited to a nuclear power plant or the like. Industrial applicability is extremely high.

DESCRIPTION OF SYMBOLS 1 Control valve 2 Housing | casing 3 Spool 4 1st press chamber 5 2nd press chamber 6 1st spring 7 2nd spring 8 1st pilot port 9 2nd pilot port 10 P port (input port)
11 A port (first output port)
12 B port (second output port)
13 Dr port (drain port)
14 First pilot passage 15 Second pilot passage 16 Control pump 17 Input passage 18 Main pump 19 First output passage 20 Actuator 21 First pressure chamber 22 Second output passage 23 Second pressure chamber 24 Drain passage 25 piston 26 tank 27 first recess 28 second recess 29 third recess 30 internal passage 31 first plate 32 second plate 33 shuttle valve 34 expansion chamber 35 magnetic responder 36 opening 37 brake valve 41 first 1 bearing 42 second bearing 43 groove 44 first opening 45 second opening 47 third bearing 48 fourth bearing 49 solid part 50 gap 51 opening 61 first valve body 62 second Valve body 63 1st support part 64 2nd support part 100 Position detector 100a Primary coil 100b, 100c Secondary coil

Claims (5)

The housing includes a housing and a spool. The housing includes a first pressing chamber, a second pressing chamber, an input port (P port), a first output port (A port), and a second output port (B port). ), And a drain port (Dr port),
The spool has a first communication portion, a second communication portion, and a third communication portion,
One end of the spool is located in the first pressing chamber, the other end is located in the second pressing chamber,
The spool is slidably supported in the housing,
The spool depends on the position in the housing,
A state in which the first communication portion communicates the input port and the first output port, and a state in which the third communication portion communicates the drain port and the second output port;
It is possible to select a state in which the first communication portion communicates the input port and the second output port, and the second communication portion communicates the drain port and the first output port. ,
The first press chamber and the second press chamber each have a first pilot port and a second pilot port for introducing working water,
The housing and the spool are formed of a rust resistant material,
The water pressure direction / flow rate control valve, wherein the first pilot port and the second pilot port are connected to a control pump capable of rotating forward and reverse.   The hydraulic pressure / flow rate control valve according to claim 1, wherein the rust-resistant material of the spool or the housing is ferritic stainless steel, two-phase stainless steel, or water-resistant resin. The water pressure direction / flow rate control valve according to claim 1, further comprising a position detector that detects a position of the spool. The spool includes a first bearing and a second bearing between the housing and the spool.
The hydraulic pressure direction / flow rate control valve according to claim 1, wherein the first bearing and the second bearing have grooves communicating with the first pressing chamber and the second pressing chamber, respectively. The spool includes a third bearing and a fourth bearing made of a porous material between the housing and the spool.
2. The hydraulic pressure direction / flow rate control valve according to claim 1, wherein one end portions of the third bearing and the fourth bearing communicate with the first pressing chamber and the second pressing chamber, respectively.

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