JPH1073181A - Pilot operated switching valve with valve position detection switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pilot-type switching valve with a valve position detection switch capable of detecting up to three valve positions of a pilot-type switching valve irrespective of fluid pressure and flow rate. . A permanent magnet (5) and a piston (4) are fitted and slid into a piston (4) joined to a main valve body (3), and are moved to the outside of a piston chamber (6) to which the pilot signal pressure is supplied. It has a magnetic sensor 7 for detecting the generated magnetic change, and a switch circuit 25 for converting the magnetic change into an electric signal. The magnetic sensor 7 forms a zigzag magnetic sensing pattern on a substrate with a magnetic metal thin film. A magnetoresistive element, which is installed with the substrate upright so as to be substantially opposed to the permanent magnets 5, and which controls the sliding range of the permanent magnets 5 by the magnetic field generated by the permanent magnets 5. By acting on the pattern, the resistance value of the magnetoresistive element is limited from a position where the resistance value is substantially minimum to a position where the resistance value is approximately maximum.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pilot type switching valve with a valve position detection switch which can detect the position of a main valve driven by a pilot signal pressure.

[0002]

2. Description of the Related Art Conventionally, a pilot type switching valve used for a pneumatic device has been used in various industries because of its low cost, labor saving and automation. In recent years, the size of pilot-type switching valves has been reduced. Some systems that require reliability include a device that detects the position of a main valve body that operates for flow path switching. As this detection device, a pressure switch or a flow switch is used.

The pressure switch and the flow rate switch detect the valve position of the pilot type switching valve by displaying an indicator for displaying the operation of the main valve body. For example, there is an indicator lamp disclosed in Japanese Utility Model Publication No. 1-35023. As shown in FIG. 10, the indicator lamp has a button battery 108 in one side of the lamp 103 with a button battery 108 in a storage chamber 107 in the lamp body 102 having a lamp 103 for operation display. Are kept in contact with each other. On the other hand, the lamp body 102
The base 105 is provided with a pressure introducing hole 111 for introducing the fluid pressure of the fluid pressure device, and a non-conductive piston 112 driven by the fluid pressure from the pressure introducing hole 111 is
It is slidably fitted in the accommodation room 107. further,
A contact 1 is provided between a lamp support 104 made of a conductive material electrically contacted with the lamp 103 and a base 105.
14 are pinched.

[0004] Indicator lamp 1 having the above configuration
In FIG. 01, the enlarged diameter portion of the spring 109 comes into contact with the contact 114 when the piston 112 is pressed and slid by the fluid pressure flowing from the pressure introduction hole 111 and attached to the end of the pilot type switching valve. Lamp 103 is turned on. In this way, the operation of the main valve body is detected. Further, the indicator lamp is miniaturized as compared with a conventional pressure switch or flow switch.

[0005] A so-called cylinder switch is known which detects the position of a piston reciprocating inside a cylinder using a magnetic field generated by a magnet attached to an end of the piston. This cylinder switch attaches reed switches to the front and rear ends of the cylinder, respectively, and detects the magnetic field generated by the magnet attached to the end of the piston when the piston moves to the mounting position of each reed switch. The position of the piston is detected by opening and closing a reed switch and outputting an electric signal from an electric contact as a position detection signal.

Alternatively, by using a magnetic sensor using a magnetoresistive element and receiving a magnetic field generated by a magnet attached to the end of the piston, the internal resistance of the magnetoresistive element changes, There is known a piston position detecting device which detects a position of a piston by converting a change in the internal resistance value into an electric signal and outputting the electric signal as a position detection signal.

[0007]

However, the conventional pressure switch and flow rate switch have the following problems. That is, these pressure switches and flow switches are
There is a problem that the system itself becomes large because it is attached to a flow path outside the pilot type switching valve. Further, the pressure switch and the flow rate switch have a range in the working pressure and the working flow rate, so that there is a problem that it is necessary to prepare several types according to the working range. Furthermore, since these pressure switches and flow switches only detect whether or not the flow path of the pilot type switching valve has been switched, the position of the main valve body can be detected only up to two positions (ON / OFF detection). There are also problems.

It is also conceivable to attach a cylinder switch to the pilot type switching valve for detecting the position of the main valve body. However, since the stroke of the main valve body in the pilot type switching valve is only a few mm, the reed switch is mainly used. It is impossible to mount three (even two) within the range in which the valve body slides.

Alternatively, when a magnetic sensor is used, two types of output voltage waveforms can be obtained depending on the mounting method. The mounting method includes a method of mounting a magnetic sensor that has been generally used in the related art while lying down (see FIG. 4A) and a method of mounting the magnetic sensor described in Japanese Utility Model Publication No. 7-4486 in an upright state. Method (Fig. 3
(See (a)). The voltage range currently used as the switch output is the use voltage range V1 or V2 shown in FIG. 3B or 4B.
When a voltage value equal to or higher than a reference voltage (hereinafter, referred to as “reference voltage value”) is input within this operating voltage range, a transistor provided in the detection circuit is driven to output a pulse-like waveform. By this, the switch output is detected. However, in the working voltage range V1 or V2 shown in FIG. 3B or FIG. 4B, the sliding range of the magnet is limited in the pilot type switching valve. Only one or two points can be output, and three switch outputs cannot be taken. Because, in the current operating voltage range, if the switch output takes three points, that is, three reference voltage values, due to the hysteresis of the magnetoresistive element and the hysteresis of the output voltage, it is highly likely that the switch output will overlap with the range of the adjacent switch output. That's why.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and is a valve position detection switch for a miniaturized pilot type switching valve. An object of the present invention is to provide a pilot type switching valve with a valve position detection switch that can detect the valve position of the valve up to three positions.

[0011]

According to a first aspect of the present invention, there is provided a pilot type switching valve with a valve position detection switch, the operator valve controlling a pilot signal pressure, and the pilot signal. A main valve element driven by pressure and a permanent magnet on a piston joined to the main valve element in a pilot type switching valve with a valve position detection switch including a valve position detection switch for detecting the position of the main valve element; The piston is fitted and slid, outside the piston chamber to which the pilot signal pressure is supplied, a magnetic sensor that detects a magnetic change generated by the movement of the permanent magnet, based on a detection signal of the magnetic sensor, And a switch circuit for outputting a valve position detection signal.

According to a second aspect of the present invention, there is provided a pilot-type switching valve with a valve position detection switch according to the first aspect. A sensor is a magnetoresistive element that forms a zigzag magnetic sensing pattern with a magnetic metal thin film on a substrate, and is installed in an upright state so that the substrate is substantially opposed to the permanent magnet, and The magnetic field generated by the permanent magnet acts on the magneto-sensitive pattern to limit the sliding range of the permanent magnet from a position where the resistance value of the magnetoresistive element is substantially minimum to a position where the resistance value of the magnetoresistive element is substantially maximum. It is characterized by the following.

According to a third aspect of the present invention, there is provided a pilot type switching valve with a valve position detection switch according to the first or second aspect of the present invention. Wherein the magnetic sensor is covered by a magnetic shielding plate made of a magnetic material.

Here, as the magnetic shielding plate, for example, a ferromagnetic iron plate or an amorphous metal plate can be used.

According to a fourth aspect of the present invention, there is provided a pilot type switching valve with a valve position detection switch according to the first or second aspect of the present invention. Wherein the lamp display is performed in conjunction with the signal output from the output circuit.

According to the pilot-type switching valve with the valve position detection switch having the above configuration, since the magnetic sensor is used, the position of the main valve body is detected regardless of the operating pressure and the operating flow rate of the pilot-type switching valve. Since no extra circuit is required in the fluid flow path, miniaturization can be achieved. In addition, by limiting the mounting method and the mounting position of the magnetic sensor, up to three position detection points of the main valve body can be obtained.

Further, since a magnetic shield plate is provided, even if the pilot type switching valve is made into a manifold, the magnetic field generated by the permanent magnet mounted on the adjacent pilot type switching valve is shielded. The position of the main valve body can be accurately detected without malfunction of the sensor.

Further, by displaying a lamp using a light emitting diode, the position of the main valve can be reliably detected only by visual observation in addition to the electric signal.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A valve position detecting switch of a pilot type switching valve according to the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 shows a pilot type switching valve with a valve position detection switch according to a first embodiment of the present invention. FIG. 1 is a sectional view of a valve position detection switch of a pilot switching valve. In FIG.
The valve position detection switch 2 includes a permanent magnet 5 embedded at the center of the end of a piston 4 joined to the main valve body 3, a magnetic sensor 7 installed outside a piston chamber 6 to which a pilot signal pressure is supplied. And a switch circuit 25 for converting a change in resistance of the magnetic sensor 7 into an electric signal. These components are mounted in the pilot type switching valve 1.

Permanent magnet 5 embedded at the end of piston 4
Has a cylindrical shape with a diameter of 2 to 3 mm, and is embedded in the center of the piston 4. Therefore, the permanent magnet 5 moves in parallel with the main valve body 3 while keeping a constant distance from the magnetic sensor 7.

The magnetic sensor 7 is a magnetoresistive element formed by etching a magnetically responsive thin film formed of a ferromagnetic metal, permalloy, on a substrate into a serpentine pattern (see FIG. 2). It is. The magnetoresistive element has a property that its resistance decreases when it receives a magnetic field perpendicular to the longitudinal direction of the pattern line (the y-axis direction in FIG. 2). In this case, the resistance value does not change. Therefore, as shown in FIG.
Are formed so as to have a phase difference of 90 degrees, and the magneto-sensitive pattern 10 formed of the magnetically responsive thin film has a high temperature dependence, and there is a practical problem as it is. further,
A ferromagnetic metal generally has a property that its internal resistance changes with temperature. Therefore, the internal resistance of the magneto-sensitive pattern 10 varies not only with the strength of the magnetic field but also with the ambient temperature. Therefore, the temperature compensation pattern 11 is created,
Compensates for changes in ambient temperature.

A method of mounting the above-described magnetic sensor will be described. Generally, as a mounting method of the magnetic sensor,
There are two types of methods shown in FIGS. 3A and 4A. As shown in FIG. 3 (a), there are a vertical mounting in which the substrate is placed upright, and a horizontal mounting in which the substrate is placed lying down as shown in FIG. 4 (a). The difference between the output voltage waveforms is that when the permanent magnet 5 moves in the x direction in the case of vertical mounting, the temperature compensation pattern 11 also receives a magnetic field perpendicular to the longitudinal direction of the pattern line. A resistance change of 10 and a resistance change of the temperature compensation pattern 11 occur, and these are combined, and the waveform of the output voltage swings to the plus side and the minus side as shown in FIG. 3B. On the other hand, in the case of horizontal mounting, even if the permanent magnet 5 moves in the x direction,
Since the magnetic field is received in the longitudinal direction of the pattern line of the temperature compensation pattern 11, there is no change in the resistance of the temperature compensation pattern 11, and therefore, as shown in FIG. It has become.

In the above two types of mounting methods, when a magnetic sensor is used as the valve position detection switch of the pilot type switching valve, the moving range of the permanent magnet is very small, so the voltage range that can be used as the switch output is: The moving range of the magnet and the output voltage linearly correspond to each other, that is, the working voltage range V1 or V2 shown in FIG. 3B or 4B, and both are almost the same range. When a reference voltage value is input within this operating voltage range, a transistor provided in the detection circuit is driven to output a pulse-like waveform, so that a switch output can be detected. FIG. 3B or FIG.
In the working voltage range V1 or V2 shown in (b), one or two points can be output.

However, when the magnetic sensor is used as a valve position detection switch of a pilot switching valve, it cannot be used for a 4-port 3-position valve or the like. That is, in order to detect the valve position of the 4-port 3-position valve, three switch outputs are required. However, in the current operating voltage range, the switch output is generated by the hysteresis of the magnetoresistive element and the hysteresis of the output voltage. This is because if three points, that is, three reference voltage values, are taken, there is a high possibility that they will overlap the range of the adjacent switch output.

Therefore, by limiting the mounting method of the magnetic sensor 7 and the sliding range of the permanent magnet 5, the operating voltage range V in which the output voltage is output linearly is as shown in FIG.
It can be 2-3 times the conventional operating voltage range. Therefore, the reference voltage value, that is, the switch output, can be reliably obtained up to three points. The sliding range of the permanent magnet 5 is as follows.
By changing the combination of the pattern width of the magnetoresistive element and the total length and diameter of the permanent magnet, it can be changed arbitrarily, so that it is possible to cope with pilot type switching valves of various sizes. The switch circuit shown in FIG. 7 detects the internal resistance of the magnetic sensor 7, converts the resistance value into a voltage value, and outputs a signal to the outside as a switch output. This circuit configuration is the same as that generally used for a cylinder switch, and is a circuit in which the output is increased by one point, and the light emitting diode emits light in response to the output signal of each of the three points. Integrated into the circuit.

The magnetic sensor 7 and the permanent magnet 5 in this embodiment
Fig. 6 shows the relationship between the mounting positions of
This will be described with reference to FIG. First, as shown in FIG. 6A, a state in which the air supply port P communicates with the output port B and the output port A communicates with the exhaust port R (hereinafter, referred to as a “first position”).
Then, the magnetic sensor 7 and the permanent magnet 4 are in the most distant state, and the output voltage value is a. Next, as shown in FIG. 6C, a state in which the air supply port P communicates with the output port A, and the output port B communicates with the exhaust port R (hereinafter, “third position”)
That. 2), the magnetic sensor 7 and the permanent magnet 4 are closest to each other, and the output voltage value is c. Finally, as shown in FIG. 6B, in the case where the output voltage value is in the middle of the above-mentioned two states, that is, in the all-port block state (hereinafter, referred to as “second position”), the output voltage value is b and Become. The output voltage value a is near the minimum value (negative value), the output voltage value b is near zero, and the output voltage value c is near the maximum value (positive value). It is equal to or greater than the output voltage difference of the used position detection switch. Therefore, even if the switch output is obtained at each of the voltage values a, b, and c, the switch output ranges at the respective points do not overlap, so that it is possible to reliably obtain the switch output at three points. These voltage values a, b, and c can be adjusted by variable resistors provided in the switch main circuit 23 shown in FIG.

The operation of the valve position detection switch of the pilot type switching valve according to the first embodiment described above will be described. First, at the first position, the decrease in the internal resistance of the magneto-sensitive pattern 10 provided in the magnetic sensor 7 is small, and the decrease in the internal resistance of the temperature compensation pattern 11 is large, so that the output voltage value becomes the minimum voltage value a. . The transistor 22 is driven by this voltage value a, and the switch output A is output, so that it can be detected that the main valve 3 is at the first position.

Next, at the second position, the permanent magnet 5 moves in the X direction in FIG. Then, the internal resistance value of the magnetic sensing pattern 10 provided in the magnetic sensor 7 decreases and the internal resistance value of the temperature compensation pattern 11 increases, so that the output voltage value increases.
Then, the output voltage value becomes b at the second position. The transistor 21 is driven by this voltage value b, and the switch output B
Is output, it is possible to detect that the main valve body 3 is at the second position.

Finally, in the third position, the permanent magnet 5
Move further in the X direction in FIG. 6 and approach the magnetic sensor 7. Then, since the internal resistance value of the magnetic sensing pattern 10 provided in the magnetic sensor 7 further decreases, the output voltage value further increases. Then, the output voltage value becomes c at the third position. Since the transistor 20 is driven by this voltage value c and the switch output C is output, it can be detected that the main valve body 3 is at the third position.

Further, as shown in FIG. 7, the switch circuit 25 is provided with a circuit for emitting a light-emitting diode in response to each switch output signal, so that the light-emitting diode emits light when the main valve body 3 is at each position. Thus, the position of the main valve body 3 can be detected. For example, if the emission color of the light emitting diode is changed corresponding to each position, the position of the main valve body can be visually detected.

As described above, according to the pilot type switching valve with the valve position detection switch according to the first embodiment, since the magnetic sensor is used, regardless of the operating pressure and the operating flow rate of the pilot type switching valve, The position of the main valve body can be detected. Further, since an extra circuit is not required in the fluid flow path, the size can be reduced.

Further, by limiting the mounting method and the mounting position of the magnetic sensor, three position detection points of the main valve body can be obtained. Furthermore, by displaying a lamp using a light emitting diode, the position of the main valve body can be reliably detected only by visual observation in addition to the electric signal.

Next, a pilot type switching valve with a valve position detection switch according to a second embodiment will be described with reference to FIGS. FIG. 8 is a front view of the valve position detection switch according to the present embodiment, and FIG. 9 is a side view of the same. Here, the valve position detection switch of the first embodiment is, for example, 10 m
It can be mounted on a small solenoid valve with a width of m, but when a small switching valve equipped with a valve position detection switch is used as a manifold, a magnetic field generated by a permanent magnet mounted on an adjacent switching valve , The magnetic sensor may malfunction. For example, in FIG. 8, focusing on the magnetic sensor 7b without the magnetic shielding plate 26, the magnetic sensor 7b receives not only the magnetic field of the permanent magnet 5b but also the magnetic fields of the permanent magnets 5a and 5c. Malfunctions.

Therefore, in the valve position detecting switch of the pilot type switching valve according to the second embodiment, the magnetic sensor 7 is used.
Is covered with a magnetic shielding plate 26 made of a magnetic material. The mounting method and the mounting position of the magnetic sensor and the permanent magnet are the same as in the first embodiment.

Therefore, the magnetic shield 26 will be described with reference to FIGS. As shown in FIG. 8, the magnetic shield 26 is attached to only one side of the pilot type switching valve. Although it may be mounted on both sides, the cost is increased, and the shielding effect is the same as in the case of one-sided mounting. Therefore, in this embodiment, the magnetic shielding plate is mounted on only one side. As shown in FIG. 9, the size of the magnetic shielding plate 26 is such that the width L1 and the length L3 of the magnetic shielding plate 26 are L2 and L2, respectively.
The mounting pitch distance between the permanent magnet 5 and the magnetic sensor 7 is L4
If it is determined that the relationship of L1 / L2> 2 and L3 / L4> 2 is satisfied, the influence of the magnetic field generated by the adjacent permanent magnet can be ignored. Since the thickness of the magnetic shielding plate 26 may be 0.1 mm or more, a foil-like material may be attached instead of an iron plate or the like.

In the present embodiment, a ferromagnetic iron plate is used as the magnetic shield, but an amorphous metal plate can also be used. Even in this case, the size of the magnetic shielding plate may satisfy the above-described conditions.

As described above, the pilot-type switching valve with the valve position detection switch according to the second embodiment has a magnetic shielding plate. Since the magnetic field generated by the permanent magnet mounted on the pilot type switching valve is shielded, the position of the main valve body can be accurately detected without malfunction of each magnetic sensor.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various applications are possible. For example, in the present embodiment, a magnetoresistive element is used as a magnetic sensor, but a Hall element or the like may be used.

[0039]

According to the pilot switching valve with a valve position detection switch of the present invention, an operator valve for controlling a pilot signal pressure, a main valve element driven by the pilot signal pressure, and a position of the main valve element A permanent magnet and a piston are fitted and slid into a piston joined to the main valve body, and the pilot signal pressure is supplied. Outside the piston chamber, a magnetic sensor that detects a magnetic change generated by the movement of the permanent magnet, and a switch circuit that outputs a valve position detection signal based on a detection signal of the magnetic sensor. The position of the main valve body can be detected regardless of the operating pressure and operating flow rate of the type switching valve, and no extra circuit is required in the fluid flow path, so miniaturization is possible. Rukoto can. In addition, by limiting the mounting method and the mounting position of the magnetic sensor, up to three position detection points of the main valve body can be obtained.

Further, since a magnetic shield plate is provided, even if the pilot type switching valve is made into a manifold, the magnetic field generated by the permanent magnet mounted on the adjacent pilot type switching valve is shielded. The position of the main valve body can be accurately detected without malfunction of the sensor.

Further, by displaying a lamp using a light emitting diode, the position of the main valve can be reliably detected only by visual observation in addition to the electric signal.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a pilot type switching valve with a valve position detection switch according to a first embodiment.

FIG. 2 is a conceptual diagram illustrating a configuration of a magnetic sensor according to the first embodiment.

FIG. 3A is a mounting method of a magnetic sensor (vertical mounting).
FIG. 4B is a diagram showing an output voltage in the same mounting state.

FIG. 4A is a mounting method of a magnetic sensor (horizontal mounting).
FIG. 4B is a diagram showing an output voltage in the same mounting state.

FIG. 5 is a circuit diagram of an electric circuit that converts a resistance change of the magnetic sensor into a voltage value.

FIG. 6 is a diagram showing an output voltage output for each positional relationship between a magnetic sensor and a permanent magnet.

FIG. 7 is a circuit diagram of the switch circuit according to the first embodiment.

FIG. 8 is a front view of a pilot type switching valve with a valve position detection switch according to a second embodiment.

FIG. 9 is a side view of a pilot type switching valve with a valve position detection switch according to a second embodiment.

FIG. 10 is a cross-sectional view of an indicator lamp, which is one type of a conventional pressure switch.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pilot type switching valve 2 Valve position detection switch 3 Main valve body 4 Piston 5 Permanent magnet 6 Piston chamber 7 Magnetic sensor 25 Switch circuit

Claims (4)

[Claims] 1. A pilot with a valve position detection switch, comprising: an operator valve for controlling a pilot signal pressure; a main valve element driven by the pilot signal pressure; and a valve position detection switch for detecting a position of the main valve element. In the type switching valve, a permanent magnet and a piston are fitted and slid into a piston joined to the main valve body, and are generated by movement of the permanent magnet outside a piston chamber to which the pilot signal pressure is supplied. A pilot switching valve with a valve position detection switch, comprising: a magnetic sensor that detects a magnetic change; and a switch circuit that outputs a valve position detection signal based on a detection signal of the magnetic sensor. 2. The pilot switching valve with a valve position detection switch according to claim 1, wherein the magnetic sensor is a magnetoresistive element that forms a zigzag magnetic sensing pattern on a substrate with a magnetic metal thin film. ,
The substrate is set upright so as to be substantially opposed to the permanent magnet, and the sliding range of the permanent magnet is changed by a magnetic field generated by the permanent magnet acting on the magneto-sensitive pattern.
A pilot type switching valve with a valve position detection switch, wherein the resistance value of the magnetoresistive element is limited from a position where the resistance value is substantially minimum to a position where the resistance value is substantially maximum. 3. The pilot position switching valve with a valve position detection switch according to claim 1, wherein the magnetic sensor is covered with a magnetic shielding plate made of a magnetic material. With pilot operated switching valve. 4. The pilot type switching valve with a valve position detection switch according to claim 1, wherein a lamp display is performed in conjunction with a signal output from said output circuit. Pilot operated switching valve with switch.