JPH10148275A - Air-operated valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact air-operated valve by reducing a cost wherein the valve, when it is opened/closed, can be accurately detected without leaking of air. SOLUTION: This air-operated valve 1 comprises a cylinder mechanism 2 provided with a piston 5 slid in a cylinder by pressure adjustment performed by compressed air supplied/discharged and a valve mechanism 3 connection provided in the cylinder mechanism 2 to be associated with sliding of the piston 5 to adjust circulation of fluid by opening/closing action of a valve element 26, and having a magnetic detector 14 mounted in a cylinder side surface of the cylinder mechanism 2 to linearly detect movement of a permanent magnet 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve for controlling the flow of gas and liquid and the flow of gas and liquid, and more particularly to an air operated valve for detecting a minute opening / closing operation.

[0002]

2. Description of the Related Art In recent years, it has become increasingly necessary to supply a small amount of fluid with high precision in a semiconductor manufacturing process or the like. Therefore, it is necessary to perform more reliable control and increase the reliability of the device. Therefore, instead of performing a unidirectional valve opening / closing operation without feeding back the open / closed state of the valve, instead of performing an air solenoid level operation detection of the air operated valve, the air operated valve body is further Attempts have been made to perform open / close detection. In other words, an operation that does not detect the operation of the air solenoid level cannot respond to abnormal operation instantaneously, and the operation detection of the air solenoid level confirms the operation state of the solenoid, but opens and closes the valve that determines the fluid flow rate. It is not done until directly confirming.
Therefore, it has not been possible to meet the demand for supplying the above-mentioned small amount of fluid with high accuracy and improving its reliability. Therefore, an attempt has been made to detect the driving state of the air operated valve body and check the flow rate of the fluid by checking the opening and closing of the valve. Therefore, as a conventional example of such an air operated valve, Japanese Patent Laid-Open Publication No.
Japanese Patent No. 79 is disclosed, which will be described below. FIG. 11 is a diagram showing a cross section of the air operated valve.

The air operated valve is roughly divided into a valve body 100, a lid portion 101, and a cylinder 10
And 2. Therefore, first, an inflow port 103 and an outflow port 104 are formed in the valve body 100, and communication holes 103a and 104a are respectively formed so as to open in the upper surface of the valve body 100. The communication hole 103a
The opening 103b is formed at the center of the valve body 100, while the opening 104b of the communication hole 104a is formed at a position shifted from the center position. Further, a diaphragm 105 is fitted to the upper end surface of the valve body 100 by a press ring 106 so as to close the communication holes 103a and 104a. The lower surface of the presser ring 106 is formed to be curved,
The diaphragm 105 has a space that can be elastically deformed. Next, the lid part 101 has a cylindrical shape, and the valve body 10
0. A cylinder 54 is provided above the lid 101. The valve stem 108 penetrating the shaft hole 107 of the lid part 101 further
Is formed through the center.

The lower end of the valve stem 108 has a press ring 106.
, And an air hole 109 is formed at the upper end. The cylinder 102 on which the valve rod 108 is provided has an air port 110 into which the tip of the valve rod 108 is slidably inserted. That is, the air port 110 is formed in a cylindrical shape protruding from the upper surface of the cylinder 102, and the air hole 109 of the valve rod 108 inserted therein communicates with the outside. And the cylinder 102
A piston 111 is fitted to the valve rod 108 so as to slide on the inner peripheral surface. A concave portion is formed on the upper surface of the piston 111 on the circumference and is urged by a coil spring 112 from above. With such a piston 111, the piston 11
A pressure chamber 113 is formed between the lower surface 1 and the upper surface of the lid 101. Here, the air hole 10 formed in the valve stem 108
9 is opened vertically to the pressure chamber 113 by being bent vertically along the axis from the upper end face of the valve rod 108 so that the pressure chamber 113 communicates with the air port 110.

The air operated valve is provided with a proximity switch 114 as a detecting device for detecting the opening / closing operation of the piston. Proximity switch 1
Reference numeral 14 penetrates the upper surface of the cylinder 102, and its tip is fixedly provided with a slight distance from the upper surface of the piston 111. At this time, the proximity switch 114 and the piston 1
The distance S from the upper surface of the eleventh surface is about 0.5 mm.

Next, the operation of such an air operated valve will be described. This constitutes a normally-closed pneumatic valve, and normally no fluid flows because the diaphragm 105 covers the opening 103b. Then, when compressed air is supplied from the air port 110, the compressed air flows through the air hole 109 of the valve rod 108 and the pressure chamber 113.
Supplied within. Then, since the pressure in the pressure chamber 113 rises, the piston 111 rises against the urging force of the coil spring 112. At this time, the valve stem 108 integrated with the piston 111 also rises, and at the same time, the diaphragm 105 joined to the lower end surface is elastically deformed and swells upward.
The opening portions 103b and 104b communicate with each other to be in an open state.

On the other hand, when the compressed air in the pressure chamber 113 is discharged, the pressure in the pressure chamber 113 decreases, the piston 111 slides downward by the urging force of the coil spring 112, and The diaphragm 105 closes the openings 103b and 104b again. In this way, the opening and closing of the valve is performed in conjunction with the vertical movement of the piston 111, and the proximity switch 114 confirms the drive of the piston 111 for the opening and closing of this valve. That is, it is confirmed whether the piston 111 is approaching or away from the proximity switch 114, and if it is approaching, the proximity switch 114 is turned on.
Is shown, and if they are separated, OFF is shown.

[0008]

However, the conventional air operated valve as described above has the following problems. First, the conventional detector that detects the driving of the piston has a problem that hysteresis is large. As a result, the detection position greatly differs depending on the traveling direction of the piston. Therefore, when the piston stroke is short (for example, 0.8 mm), the display indicating the open / closed state is significantly different from the actual state, and the reliability is low.
Also, a high mounting accuracy is required for mounting the detector.

[0009] Further, the conventional one causes an increase in the production cost of the air operated valve. this is,
Since the proximity switch 114 directly detects the drive position of the piston 111, the proximity switch 114 needs to be mounted through the cylinder 102, which makes the production complicated. In addition, since the proximity switch 114 is inserted into the cylinder 102 as described above, the space in the cylinder 102 is greatly reduced. For example, another arrangement such as a spring inserted into the cylinder 102 is restricted by its arrangement. And the size of the cylinder 102 becomes larger. Further, if the proximity switch 114 is inserted into the cylinder 102, there is a possibility that compressed air supplied to drive the piston 111 leaks.

Accordingly, an object of the present invention is to provide a compact air operated valve which can accurately detect the opening and closing of a valve and does not leak air at a low cost in order to solve the above problems. .

[0011]

An air operated valve according to the present invention for achieving the above object is provided with a cylinder mechanism having a piston that slides in a cylinder by adjusting a pressure, and is associated with the cylinder mechanism. It has a valve mechanism that opens and closes a valve in conjunction with sliding of a piston, and a magnetic detector that is attached to the side of the cylinder of the cylinder mechanism and linearly detects the movement of a permanent magnet mounted on the piston. Further, the air operated valve of the present invention has a cylinder mechanism provided with a piston that slides in a cylinder by pressure adjustment, and a diaphragm that is associated with the cylinder mechanism and that opens and closes minutely in conjunction with the sliding of the piston. A valve mechanism having a valve or a bellows valve, and attached to the cylinder side surface of the cylinder mechanism, linearly detects the movement of a permanent magnet attached to the piston, and moves the minute opening / closing state of the diaphragm valve or the bellows valve over an operation range. And a magnetic detector for detecting the magnetic field.

Further, the air operated valve of the present invention has a cylinder mechanism provided with a piston which slides in the cylinder by adjusting the pressure, and a fine opening / closing mechanism which is interlocked with the cylinder mechanism and interlocks with the sliding of the piston. A valve mechanism having a diaphragm valve or a bellows valve for performing the following, and a magnetic detector attached to a cylinder side surface of the cylinder mechanism for detecting a minute opening / closing state of the diaphragm valve or the bellows valve by movement of a permanent magnet mounted on the piston. And

In the air operated valve according to the present invention, the magnetic detector is a magnetoresistive element having a magnetoresistive effect, wherein the magnetic detector is formed on a substrate by a deposited thin film of a ferromagnetic metal. A magnetic linear scale formed in a direction perpendicular to the direction in which the permanent magnet mounted on the piston moves, and having a density or a line width or a density and a line width linearly changing in the direction in which the permanent magnet moves. Desirably. Also,
In the air operated valve of the present invention, it is preferable that the magnetic detector has two semi-fixed resistors for changing a reference value for detecting a piston position.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the air operated valve of the present invention for achieving the above object, the pressure in the cylinder is adjusted by supplying or discharging compressed air, and the piston slides due to the pressure fluctuation in the cylinder. Then, the valve opens and closes via the connecting means in conjunction with the sliding of the piston. At this time, a magnetic detector attached to the side of the cylinder of the cylinder mechanism linearly detects the movement of the permanent magnet attached to the piston when the valve is opened or closed. Further, the air operated valve of the present invention,
The pressure in the cylinder is adjusted by the supply or discharge of the compressed air, and the piston fluctuates due to the pressure fluctuation in the cylinder, and the diaphragm valve or the bellows valve connects the connecting means in conjunction with the sliding of the piston. Micro opening and closing. At this time, a magnetic detector attached to the side of the cylinder of the cylinder mechanism linearly detects the movement of a permanent magnet mounted on the piston, and operates in a range of opening and closing of a diaphragm valve or a bellows valve that performs minute opening and closing. Perform accurate detection over

In the air operated valve of the present invention, the pressure in the cylinder is adjusted by the supply or discharge of compressed air, and the piston fluctuates due to the pressure fluctuation in the cylinder, thereby interlocking with the sliding of the piston. The diaphragm valve or bellows valve opens and closes minutely via the connecting means. At this time, regarding the open / closed state of the diaphragm valve or bellows valve that performs minute opening / closing in conjunction with the driving of the piston, the movement of the permanent magnet mounted on the piston is determined by a magnetic detector attached to the side of the cylinder of the cylinder mechanism. Detect accurately.

In the air operated valve of the present invention, the magnetic linear scale of the magnetic detector serving as a switch is such that when the permanent magnet fixed to the piston moves in parallel with the magnetic linear scale while maintaining a constant interval, The electric resistance decreases according to the strength of the magnetic field generated by the permanent magnet. At this time, since the density of the magnetic linear scale changes linearly in the moving direction of the permanent magnet, the position of the permanent magnet and the decreasing value of the electrical resistance correspond one-to-one. Therefore, the position of the piston can be measured by measuring the change in the resistance value. By comparing this resistance value with the reference value, whether the valve is open or not
Alternatively, it is determined whether or not it is in the closed state, and the determination is output. Further, in the air operated valve of the present invention, the magnetic detector changes a reference value for detecting the piston position by two semi-fixed resistors, and adjusts the piston position indicating the open state or the closed state.

[0017]

Next, a first embodiment of an air operated valve according to the present invention will be described with reference to the drawings. FIG.
FIG. 3 is a cross-sectional view of an air operated valve. The air operated valve 1 of the present embodiment is roughly composed of a cylinder portion 2 and a valve portion 3. Cylinder part 2
A rod 6 is disposed around the axis in the cylinder 4, and a piston 5 fixed to the rod 6 is slidably fitted. On the other hand, a supply / exhaust port 7 for supplying and discharging compressed air is formed at the center of the upper surface of the cylinder 4, and a small-diameter exhaust hole 12 is formed at the upper surface. The upper end of the rod 6 is inserted into a supply / exhaust port 7 formed on the upper surface of the cylinder 4. That is, the air supply / exhaust port 7 is formed such that the upper wall surface of the cylinder 4 projects inward by a predetermined distance, and has an insertion hole into which the rod 6 can be inserted.

The rod 6 inserted into the air supply / exhaust port 7 has a rod extending from the upper end surface to the pressure chamber 9 formed between the piston 5 and the lid body 8 and at the position of the pressure chamber 9 in the lateral direction. Air supply / exhaust holes 10 are formed so as to penetrate through holes 6.
A ring magnet 13 is fitted on the lower surface of the piston 5 having the rod 6 fixed to the shaft so as to extend along the outer periphery of the piston 5. A concave portion is formed in the upper surface of the piston 5 in a circumferential shape, and the coil springs 11a and 11b are fitted therein so as to urge the piston 5 downward. Incidentally, a magnetic detector 14 is mounted on the outer peripheral portion of the cylinder 4 in the air operated valve 1. Specifically, a magnetic linear scale 15 for detecting the ring magnet 13 fitted on the piston 5 is provided on a mounting board 16 on which a detection circuit is mounted, and a lead for extracting a detection signal from the magnetic linear scale 15 is provided. Wires are connected. The details of the magnetic linear scale 15 will be described later.

Next, an inflow port 21 for inflow of fluid and an outflow port 2 for outflow of fluid are provided in the valve portion 3.
2 are formed in the valve body 20, and both are communicated with openings 23 and 24 provided on the upper surface of the valve body 3. Especially,
The opening 23 communicating with the inflow port 21 is formed at the center of the valve body 20 so as to be located coaxially with the rod 6.
A valve seat 25 is formed around the opening 23, and a diaphragm 26 is formed on the upper surface so as to close the valve seat 25.
Is fitted. Incidentally, the diaphragm 26 is fixed to a lower end of a cylinder 27 provided above the valve body 20. A piston 28 is slidably fitted to the upper end of the cylinder 27 on the inner peripheral surface of the cylinder 27, and the piston 28 is fixed to the lower end of the rod 6 that has penetrated the lid 8.

Next, the magnetic linear scale 15 will be described. Four types of schematic configurations of the magnetic linear scale 15 are shown. FIG. 2 shows a first configuration example in which the line width W1 of the magnetoresistive element R1 is constant and the density is sequentially changed. FIG. 3 shows a second configuration example in which the density of the magnetoresistive element R1 is constant and the line width is sequentially changed. FIG. 4 shows a third configuration example in which the density of a pattern having a wide line width while the density of the magnetoresistive element R1 is constant is sequentially changed. FIG. 5 shows a fourth configuration example in which the first configuration example and the second configuration example are combined. In each configuration example, the magnetoresistive element R1 has a constant width W in a direction orthogonal to the direction B in which the permanent magnet 57 moves.
B, and the density changes linearly in the direction B in which the permanent magnet 31 moves.

FIG. 6 shows a first example of the configuration of the magnetic linear scale 15 utilizing the magnetoresistive element R1. On the magnetic linear scale 15, two serpentine patterns of the magnetoresistive element R1 and the temperature compensating circuit R2 are formed so as to have a quadrature phase difference. here,
As shown in a partially enlarged view of FIG. 7A, the magnetoresistive element R1 is formed in a constant and linear pattern with a line width W1 = 20 μm. The meandering interval WA of the magnetoresistive element R1 is WA1 = 1.085 mm at the left end.
From, to WA77 = 0.325 mm at the right end,
39 reciprocations are performed while reducing the meandering interval WA by 0.01 mm. Thereby, the magnetoresistive element R1
Has changed more than three times. The magnetic linear scale 15 of this embodiment has a width of 3 mm and a length of about 60 mm.
According to the magnetic linear scale 15 of the present embodiment, the density is changed while the width of the serpentine pattern of the magnetoresistive element R1 is kept constant.
5 can be reduced to 3 mm.

The temperature compensating circuit R2 is shown in FIG.
As shown in the partial enlarged view, the pattern is formed as a four reciprocating serpentine pattern with a line width W2 = 4 μm. In the present embodiment, both the permalloy (Ni-F) is used as the ferromagnetic metal as the material of the magnetoresistance element R1 and the temperature compensation circuit R2.
e, 83:17). Magnetoresistance element R1
Has the property that the resistance decreases when it receives a magnetic field perpendicular to the longitudinal direction of the pattern lines, and when it receives a magnetic field in the longitudinal direction of the pattern lines, the resistance value decreases. It does not change. Terminal portions 32 and 33 are provided at both ends of the magnetoresistive element R1.
Are provided, and terminals 33 and 3 are provided at both ends of the temperature compensation circuit R2.
4 are provided.

Next, the detection circuit of the mounting board 16 will be described. FIG. 8 shows a detection circuit of the magnetic linear scale 15. A DC voltage Vcc is applied between the terminals 32 and 34 of the magnetic linear scale 15. Magnetic linear scale 1
5, the first comparator 41 is connected to the terminal 33 of the midpoint voltage.
And the negative input terminal of the second comparator 42 are connected. On the other hand, the plus side input terminal of the second comparator 42 is connected to ground via a resistor 43, and is connected to V
Connected to cc. The negative input terminal of the first comparator 41 is also connected to ground via a resistor 45 and to Vcc via a variable resistor 46.

The output terminals of the first comparator 41 and the second comparator 42 are a resistor 47 and a resistor 48, respectively.
Is connected to Vcc. Further, the outputs of the first comparator 41 and the second comparator 42 are connected to the bases of the transistors 49 and 50. An indicator light (LED) 51 and an indicator light 52 connected to Vcc via resistors 53 and 54 are connected to the emitters of the transistor 49 and the transistor 50, respectively. On the other hand, the collector of the transistor 49 is connected to the base of the exit transistor 55, and similarly, the collector of the transistor 50 is connected to the base of the exit transistor 56. The collector of the outlet transistor 55 is connected to the output 1, the collector of the outlet transistor 56 is connected to the output 2, and the respective emitters are connected to the ground.

Next, the operation of the air operated valve of this embodiment will be described. Air operated valve 1
When the compressed air is not initially supplied into the pressure chamber 9, the piston 5 is urged downward by the coil springs 11a and 11b. Accordingly, the rod 6 moves down together with the piston 5, and the piston 28 fitted to the tip of the rod 6 moves down, so that the pressure in the cylinder 27 increases and the diaphragm 26 is pressed against the valve seat 25. Therefore, the fluid from the inflow port 21 is blocked by the diaphragm 26 and does not flow to the outflow port 22. On the other hand, compressed air for driving the air operated valve 1 is supplied. That is, when the compressed air is supplied into the cylinder 4 from the supply / exhaust port 7 on the upper surface of the cylinder 4, it flows into the pressure chamber 9 through the supply / exhaust hole 10 formed in the rod 6. Therefore, the pressure in the pressure chamber 9 into which the compressed air has flown is increased, and the balance with the coil springs 11a and 11b for urging the piston 5 downward is lost, so that the piston 5 rises. At this time,
It rises with the ring magnet 13 disposed below the piston 5.

When the rod 6 rises, the piston 28 fitted to its lower end also rises, so that the pressure in the cylinder 27 decreases and the diaphragm 26 is deformed upward. Therefore,
Since the diaphragm 26 is separated from the valve seat 25 by deformation, the inflow port 21 and the outflow port 22 communicate with each other, so that the fluid flows. Conversely, when the flow path of the fluid is shut off to stop the flow of the fluid, the diaphragm 26 is brought into contact with the valve seat 25 and shut off. For this purpose, the piston 5 is lowered by discharging the compressed air from the pressure chamber 9. The compressed air is discharged from the supply / exhaust port 7 through the supply / exhaust hole 10 in the opposite direction to the supply. Then, the pressure chamber 9
Due to the pressure drop inside, the biasing force of the coil springs 11a and 11b is superior, and the piston 5 descends. Then, the piston 28 at the lower end of the rod 6 is also lowered, and the pressure in the cylinder 27 is increased to hold down the diaphragm 26 and block the flow path. As described above, in the air operated valve 1 of the present embodiment, the diaphragm 2 is moved in accordance with the vertical movement of the piston 5.
6 is deformed and the opening and closing with the valve seat 25 is repeated.

By the way, in the air operated valve 1 of this embodiment, it is confirmed by the magnetic detector 14 whether or not the adjustment of the fluid by such driving is surely performed. Thus, the operation of the detection circuit mounted on the mounting board 16 having the above configuration will be described.

FIG. 9 shows a magnetic linear scale 1 according to the first embodiment.
5 shows the experimental data. The horizontal axis indicates the position of the ring magnet 13 as the movement distance, and the vertical axis indicates the output. Ring magnet 1
3 is data of an experiment in which a permanent magnet is translated in the longitudinal direction of the magnetic linear scale 15 in a state where the distance between the ring magnet 13 attached to the piston 5 and the magnetic linear scale 15 is 2 mm. As can be seen from this, in the case of the present embodiment, the output hysteresis in each direction is almost zero and can be indicated as zero. This is because, as the ring magnet 13 moves from the left end to the right end of the magnetic linear scale 15, the density of the magnetic linear scale 15 increases, and the internal resistance of the magnetoresistive element R1 decreases. It decreases in proportion to the decrease in the internal resistance of the magnetoresistive element R1. It can be seen that the position of the ring magnet 13 can be detected linearly by the output voltage.

Here, as shown in FIG. 9, in this embodiment, the piston 5 is driven with the distance from the point P to the point S as the piston stroke. Actually, this distance is 0.8 mm, the point P indicates the valve open state at the upper stop point, and the point S indicates the valve closed state at the lower stop point. The Q and R points between P and S are set as output points, and the opening and closing of the valve is displayed between P and Q and between R and S. The output voltages of the magnetic linear scale 15 at that time are E1 and E2. The output voltages E1 and E2 are applied to the minus terminal of the first comparator 41 and the plus terminal of the second comparator 42 by variable resistors 46 and 44, respectively.

Therefore, when the ring magnet 13 is between P and Q, the midpoint voltage of the magnetic linear scale 15 is higher than E1. At this time, when the midpoint potential is input to the plus terminal of the first comparator 41, the output goes to a high level, a voltage is applied to the base of the transistor 49, and the light emitting diode 5
1 is turned on when current flows. Further, the transistor 55
Is applied, the output 1 is turned on. Next, when the piston 5 is moved and the ring magnet 13 is between QR, the midpoint voltage (Ex) of the magnetic linear scale 15
Becomes E2 <Ex <E1. At this time, the outputs of the first and second comparators 41 and 42 are both at the low level, and since no voltage is applied to the bases of the transistors 49 and 50, the outputs 1 and 2 are turned off.

Further, the piston 5 moves and the ring magnet 1
When 3 is between R and S, the midpoint voltage of the magnetic linear scale 15 becomes lower than E2. At this time, when the output is input to the minus terminal of the first comparator 42, the output goes high, a voltage is applied to the base of the transistor 50, a current flows through the light emitting diode 52, and the light is turned on. further,
Since a voltage is applied to the base of the transistor 56, the output 2
Turns on.

The configuration and operation of the air operated valve according to the present embodiment have been described above. According to this, the following effects can be obtained. In the air operated valve of the present embodiment, since the magnetic linear scale with small hysteresis is used for the magnetic detector 14, it is not affected by the driving direction of the piston at both ends of the operating range of the piston, and the detection can always be performed at a predetermined position. It has become possible. As a result, the detection positions at both ends can be clearly distinguished even when the valve is minutely opened and closed, that is, when the piston is minutely driven. Therefore, by changing the variable resistors 44 and 46, it is possible to provide the air operated valve 1 that can accurately detect an arbitrary point even at a very small distance within an operating range of 1 mm or less, which is difficult in the related art. did it. At this time, since the sensitivity of the magnetic detector 14 is not affected even if the variable resistors 44 and 46 are changed, stable operation can be performed even if the operation range is narrow.

Also, since the magnetic detector 14 is externally attached to the cylinder 4, it is possible to reduce the production cost without requiring any processing for mounting.
Its creation has also become simple. By changing the two variable resistors 44 and 46, the magnetic detector 14 is turned on at an arbitrary position of the ring magnet 13.
Can be set, which is convenient. Also,
Setting is easy even when the object changes. Furthermore,
By providing the magnetic detector 14 externally to the cylinder 4, a space inside the cylinder 4 is ensured, and there is no problem in design, and there is no problem that the cylinder 4 itself becomes large.

Next, a case where the ambient temperature changes will be described. The temperature compensation circuit R2 will be described. FIG. 10 shows data obtained by experiments performed by the inventor. The horizontal axis shows the line width of the pattern in micron units, and the vertical axis shows the magnetoresistance change rate when the pattern is used as the magnetoresistance element R1. Data obtained when the magnetic field strength was tested at 100 gauss is indicated by a dotted line L1, data obtained when the magnetic field strength was tested at 50 gauss is indicated by a dashed line L2, and data obtained when the magnetic field strength was tested at 25 gauss are indicated by a solid line L3. Show.

According to this data, it can be seen that as the pattern width decreases, the magnetoresistance ratio of the magnetoresistive element decreases. Therefore, when a pattern having a line width smaller than the pattern width of the magnetoresistive element R1 is used as the temperature compensating circuit R2, the influence of the magnetic field strength of the temperature compensating circuit R2 is small. It is possible to perform temperature compensation more accurately than the temperature compensation circuit that has been used. That is, as compared with a temperature compensation circuit using a pattern with a large line width, the temperature compensation circuit using a pattern with a small line width has a smaller line width by an amount affected by the strength of the magnetic field. Even if there is an error in the manufacturing accuracy of the device, accurate temperature compensation can be performed.

Further, from this data, it is understood that when the line width of the line forming the pattern of the magnetoresistive element is set to 6 μm or less, the magnetoresistance change rate is significantly reduced. Therefore, when the pattern width is set to 6 μm or less, even when a ferromagnetic metal thin film made of the same material as the magnetoresistive element is used, the rate of change in the internal resistance of the thin film due to the strength of the magnetic field is small. On the other hand, the change in the internal resistance value due to the change in ambient temperature is
Since it is not affected by the pattern width, it can be seen that if a ferromagnetic metal thin film is formed with a pattern width of 6 μm or less, it has excellent properties as a temperature compensation circuit.

That is, since the temperature compensating circuit R2 is made of a ferromagnetic metal thin film made of the same material as the magnetoresistive element R1 and has a pattern width of 6 μm or less, the temperature may vary due to variations in the etching process in the manufacturing process. Since the compensation circuit R2 is hardly affected, accurate temperature compensation can always be performed. Further, the shape of the temperature compensation circuit R2 can be determined independently of the shape of the magnetoresistive element R1, and the size of the temperature compensation circuit R2 can be reduced as shown in FIG.

Next, a description will be given of a second embodiment of the air operated valve according to the present invention. In this embodiment, the same air operated valve as that of the first embodiment is used, and only the characteristic portions will be described below. FIG. 11 is a view showing a side surface of the air operated valve of the second embodiment. An MR element (not shown) is used for the magnetic detector 71 mounted on the air operated valve 70 of the present embodiment. However, a conventional MR element that has been conventionally marketed has a hysteresis of about 0.2 mm, and its mounting accuracy is strictly required. Therefore, it is necessary to attach a low hysteresis MR element. In this embodiment, in particular, the MR element disclosed in Japanese Patent Application Laid-Open No. Hei 5-235435 filed by the present applicant (the details will be described later). Is used. The OPEN display 72 for displaying the state of the valve and a C signal are displayed on the MR element.
A LOSE display 73 is connected. Specifically, OP
The EN display 72 is indicated by a CLOS
The E display 73 is configured by an LED that emits green light.

FIG. 12 is a configuration diagram of a magnetic linear scale having a low hysteresis MR element disclosed in Japanese Patent Application Laid-Open No. 5-235435. . Magnetoresistance element 81
The temperature compensating element 82 is formed as a pattern having a constant line width. The patterns of the magnetoresistance element 81 and the temperature compensation element 82 are formed so as to have a quadrature phase difference. The magnetoresistive element 81 and the temperature compensating element 82 have such a property that the internal resistance decreases when a magnetic field is applied at right angles to the longitudinal direction of the pattern line. When receiving a magnetic field, the internal resistance does not change. Therefore, as shown in FIG. 12, when the permanent magnet 87 moves in the direction of the arrow A, the internal resistance of the magnetoresistive element 81 changes while the internal resistance of the temperature compensation element 82 does not change. At this time, the change in the resistance value of the magnetoresistive element 81 is
The strength of the temperature compensated magnetic field is measured by 84 and 85.

The air operated valve 70 according to the second embodiment having the above-described configuration is similar to the air operated valve 70 according to the first embodiment, and detects the transfer of a permanent magnet provided on a piston driven by a magnetic detector 71 to thereby operate the valve. Is detected. At this time, the state when the valve is opened and when the valve is closed is accurately detected by the MR element, and the detection signal is output from the OPE.
Input to the N display 72 or the CLOSE display 73,
ED is emitted.

Therefore, in the air operated valve 70 of the present embodiment, since the MR element having a small hysteresis is used, it is possible to always detect at the predetermined position.
It has the same effects as the first embodiment, such as the fact that it is possible to reduce the production cost by external attachment, and furthermore, the provision of LED display means makes it easy to grasp the state. .

It should be noted that the present invention is not limited to the above embodiment, and various changes can be made without departing from the spirit of the present invention. For example, in the above embodiment, two variable resistors are used, but only one of them may be used. In that case, it is necessary to adjust according to the mounting position of the magnetic detector. Further, in the embodiment, the output when the piston is at the upper end and the lower end is shown in order to notify the open / closed state of the valve. It may be shown. Further, in the embodiment, the OPEN display 72 and the CLOSE display 73 are provided, but one switch may be used to detect only one of them. Further, in the embodiment, the OPEN display 72 is red, and the CLO
Although the SE display 73 is green, the combination of colors may be reversed or any other color may be used.

[0043]

According to the air operated valve of the present invention, the piston in the cylinder is slid by adjusting the pressure, and the flow of the fluid is adjusted by opening and closing the valve in conjunction with the sliding of the piston. The opening / closing of the valve that adjusts the flow rate of the permanent magnet mounted on the piston is detected by a magnetic detector mounted on the side of the cylinder that can detect the movement of the permanent magnet. Detection is possible, and a compact air operated valve without air leakage can be provided at low cost.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a configuration of an air operated valve according to a first embodiment of the present invention.

FIG. 2 is a conceptual diagram showing a magnetic linear scale of the first configuration example.

FIG. 3 is a conceptual diagram showing a magnetic linear scale of a second configuration example.

FIG. 4 is a conceptual diagram showing a magnetic linear scale of a third configuration example.

FIG. 5 is a conceptual diagram showing a magnetic linear scale of a fourth configuration example.

FIG. 6 is a plan view showing the configuration of the magnetic linear scale of the first embodiment.

FIG. 7 is a partially enlarged view showing details of the configuration of the magnetic linear scale of the first embodiment.

FIG. 8 is a detection circuit diagram of the magnetic detector.

FIG. 9 is a diagram for explaining the operation of the detection circuit.

FIG. 10 is a data diagram showing a magnetoresistance change rate of a magnetoresistance element.

FIG. 11 is a view showing a side surface of an air operated valve of a second embodiment according to the present invention.

FIG. 12 is a configuration diagram of a magnetic linear scale used in an air operated valve of a second embodiment according to the present invention.

FIG. 13 is a cross-sectional view illustrating a configuration of an air operated valve of a first conventional example.

[Description of Signs] 1 Air operated valve 4 Cylinder 5 Piston 13 Ring magnet 14 Magnetic detector 15 Magnetic linear scale 20 Valve body 25 Valve seat 26 Diaphragm 41 First comparator 42 Second comparator 44 Variable resistor 46 Variable resistor

Claims (3)

[Claims] 1. A cylinder mechanism having a piston that slides in a cylinder by pressure adjustment, and a diaphragm valve or a bellows valve that is associated with the cylinder mechanism and that opens and closes minutely in conjunction with the sliding of the piston. A valve mechanism having a magnetic detector that linearly detects a minute opening / closing state of the diaphragm valve or the bellows valve over an operation range by moving a permanent magnet mounted on the piston, wherein the magnetic detector is An air operated valve attached to a side surface of a cylinder of the cylinder mechanism. 2. A cylinder mechanism having a piston that slides in a cylinder by pressure adjustment, and a diaphragm valve or a bellows valve that is associated with the cylinder mechanism and that opens and closes minutely in conjunction with the sliding of the piston. A valve mechanism having a magnetic detector for detecting a minute opening / closing state of the diaphragm valve or the bellows valve by movement of a permanent magnet mounted on the piston, wherein the magnetic detector is provided on a cylinder side surface of the cylinder mechanism. An air operated valve characterized by being attached. 3. The air operated valve according to claim 1, wherein the magnetic detector has two semi-fixed resistors for changing a reference value for detecting a piston position. Air operated valve.