JPH10122415A - Miniature solenoid valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a miniature solenoid valve which is used with a short stroke, and is formed in a small size without reducing cleaning degree, for increasing attraction force. SOLUTION: A solenoid valve 1 is integratedly constituted providing with a valve part 2, a solenoid 3, and a circuit chamber 4. In the valve part, a valve element 22 provided with a hollow part 21, and a poppet valve 23 vertically moved in the hollow part 21, are arranged, and a diaphragm 24 is arranged to deviate the inside of the hollow part 21 into valve chambers 21b of a solenoid side and a solenoid side which is opposed thereto. The solenoid 3 is provided with E-shaped cross sectional fixed iron core 31 and movable iron core 32 having center yokes 31a, 32a on its center part, and a pin 33 fixed on the center shaft part of the movable iron core 32. One end of the pin 33 is connected to the poppet valve 23, and a leaf spring 34 is installed on the other end penetrating the fixed iron core 31. A coil 35 is wound around an outer periphery of the center yokes 31a, 32a so as to form a solenoid valve in a small size. An attraction area of the center yoke is formed so as to be set a ratio of all cross sectional areas of the solenoid to 20 to 30%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic valve which requires a small suction force in a small stroke range without reducing the cleanness of a fluid passing through the valve.

[0002]

2. Description of the Related Art Conventionally, in a solenoid valve which is required to have a high degree of cleanliness, for example, a solenoid valve used in a clean room, the fluid (air, special gas, tap water or pure water) passing through the valve has dust. Various efforts have been made to prevent contamination from occurring and the generation of dust from the solenoid valve itself. For example, in a valve, without using a spool valve configured to be slidable between a valve and a valve seat,
The tip portion is formed in a tapered shape, and a poppet valve that opens and closes the fluid inlet with a tapered surface is used.Also, so as not to mix wear powder from the solenoid, split the valve chamber where the poppet valve moves. A diaphragm or the like is arranged. Further, when a long stroke is required, an air cylinder is connected to the poppet valve to operate the poppet valve, and the air cylinder is operated by a solenoid.

A conventional solenoid valve 7 using a diaphragm
8, the solenoid is a plunger type, that is, a movable plunger 74 is provided in a coil body 73.
Is provided, and a pin 75 fixed to the movable plunger 74 is provided.
Is connected to a poppet valve 76, and a solenoid 72 provided with a spiral spring 78 for returning the movable plunger 74 attracted to the fixed iron core 77 is mainly used. The hollow chamber 79 in which the poppet valve 76 is moved has an air chamber 79a on the solenoid side and a valve chamber 79b on the anti-solenoid side.
And a diaphragm 80 for dividing the above.

[0004]

However, the conventional solenoid valve 71 uses a solenoid 72 of a type in which the coil body 73 is disposed so as to fit the outer peripheral surface of the fixed iron core 77 or the movable plunger 74. Therefore, the solenoid valve 71 itself was enlarged. With a larger solenoid, a larger diaphragm 80 will be attached. Therefore, the pressure from the fluid received by the diaphragm 80 also increases, and the urging force of the spiral spring 78 must be increased accordingly, so that the size of the solenoid valve is further increased. In addition, the valve in which the cylinder is disposed is also increased in size by the space of the cylinder.

An object of the present invention is to solve the above-mentioned problems, and an object of the present invention is to provide a small-sized solenoid valve which can be used in a short stroke range and which can be reduced in size without lowering the cleanness and which can increase the attraction force. I do.

[0006]

Means for Solving the Problems In order to solve the above-mentioned problems, a small solenoid valve according to the present invention is configured as follows. That is, a valve that moves in the valve chamber, a valve seat having a passage opening that can be opened and closed by the valve,
And a circuit core having a fixed iron core, a movable iron core that can be attracted to the fixed iron core by exciting the coil, and a circuit board that controls the coil of the solenoid. And a hollow portion is formed in the valve portion on the solenoid side, and the hollow portion is divided into an atmosphere chamber on the solenoid side and a valve chamber on the anti-solenoid side. The fixed iron core is formed in a substantially E-shaped cross section having a center yoke at the center and a cylindrical yoke at the periphery, and the movable iron core is formed at a center yoke at the center and a cylindrical yoke at the periphery. And a coil is wound between the center yoke and the cylindrical yoke to form a movable iron core of the solenoid. A pin, which is disposed so as to penetrate the movable core and the fixed core and is formed so that one end thereof is connected to the valve, is fixed to the mandrel, and a center yoke of the fixed core and A cylindrical yoke is formed so as to have a suction area secured to maintain a suction force with the movable core, and separates the movable core from the fixed core when the movable core is released from suction. And a sensor for detecting the attraction of the movable iron core is provided in the circuit chamber.

[0007] Preferably, the suction area between the center yoke of the fixed core and the movable core is at least 20% to 30% of the sectional area of the solenoid. Anything should do.

[0008] Further, it is more preferable that the spring means is configured to have a leaf spring.

Further, a circuit is provided on the circuit board for switching the coil current to a holding current having a current value lower than the starting current in response to a confirmation signal of the adsorption of the movable core by the sensor. More preferred.

Further, the valve may be a poppet valve.

It is further preferable that a reverse excitation timer for outputting a reverse excitation voltage is provided on the circuit board.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. A small solenoid valve (hereinafter, referred to as a solenoid valve) 1 is used particularly in a short stroke (within a range of about 0.5 mm), and is a valve section 2 for opening and closing a flow of a fluid.
And a solenoid 3 for operating the valve by exciting the coil
And a circuit chamber 4 for controlling the coil current.

The valve portion 2 includes a valve body 22 having a hollow portion 21 on the solenoid 3 side, and a poppet valve 23 which reciprocates linearly in the hollow portion 21. Poppet valve 23
Is a conical portion 23a having a tapered tip,
A cylindrical diaphragm fixing portion 23b disposed above the conical portion 23a, and connected to a pin of the solenoid 3 described later. Further, a diaphragm 24 made of rubber or a thin metal plate is provided in the hollow portion 21 so as to be divided into an atmosphere chamber 21a on the solenoid side and a valve chamber 21b on the anti-solenoid side, and is formed on the inner peripheral surface on the hollow portion 21 side. A diaphragm fixing screw 25 screwed to the female screw fixes the diaphragm 24. The diaphragm 24 is formed of a circular rubber or a thin metal plate, and has a central portion inserted between the conical portion 23a of the poppet valve 23 and the diaphragm fixing portion 23b. Therefore, when the conical portion 23a of the poppet valve 23 moves, the diaphragm 24 bends so that the central portion moves vertically with respect to the fixed outer peripheral portion. Further, an inflow port 26 into which fluid flows into the valve element 22, a passage 27 formed from the inflow port 26 toward the valve chamber 21 b,
A passage 29 formed from 1b toward the outlet 28;
Is provided. Then, the poppet valve 23 is connected to the passage 27.
It is opened and closed with respect to.

The solenoid 3 includes a fixed iron core 31, a movable iron core 32 movable with respect to the fixed iron core 31, and a movable iron core 3.
2 is fixed so as to penetrate the central shaft portion, one end portion is extended to penetrate the fixed iron core 31 to fix the leaf spring 34, and the other end portion is connected to the poppet valve 23. And a pin 33. The leaf spring 34 is formed in a band shape, and is disposed in a narrow space between the fixed iron core 31 and the circuit chamber 4 so as to urge the pin 33 toward the valve portion 2.

The fixed iron core 31 and the movable iron core 32 are shown in FIGS.
As shown in the figure, the cross section in the direction perpendicular to the axis is circular and the cross section in the axis direction is formed substantially in the shape of E, and the central convex portion is formed on the suction surface as the center yokes 31a and 32a. The outer convex portion is a cylindrical yoke 31b / 3
2b is formed on the suction surface and is arranged so that the center yokes 31a and 32a face each other. The center yokes 31a and 32a and the cylindrical yokes 31b and 32
The coil 35 is wound around the concave portions 31c and 32c formed between the coil 35b and the concave portion 31c of the fixed iron core 31 and the concave portion 32c of the movable iron core 32 (generally referred to as an E-type solenoid).

When the coil 35 is excited, the center yokes 31a and 32 at the opposing positions
a and the cylindrical yokes 31b and 32b are attracted. In particular, the attracting area of the center yokes 31a and 32a greatly affects the attracting efficiency of the small solenoid. This adsorption efficiency has been clarified by some experimental results.
As shown in the graph of FIG. 3, a constant current value (2 A)
The suction force of the solenoid may be about 14 kg / A or more, desirably about 16 kg / A or more, and therefore, the ratio of the cross-sectional area of the solenoid to the center yoke suction cross-sectional area may be 20% to 30%. Preferably 22%
It has been found that it is good to set it to 26%. Therefore, in this embodiment, the outer diameter of the solenoid is about 37 mm.
In contrast, the outer diameter of the center yoke is set to about 18 mm.

The movable iron core is not limited to the above-described embodiment. As shown in FIG. 4, the movable iron core 52 has a flat cross section.
But it is good (generally called a flat solenoid). In this case, in the fixed iron core 51, all the coils 35 are wound around a concave portion 51c formed between the center yoke 51a and the cylindrical yoke 51b. Therefore, the fixed core 51 has a longer overall length than the fixed core 31 shown in FIG. A pin 53 is fixed to the central shaft portion of the movable iron core 52, and one end is attached so as to penetrate through the fixed iron core 51 and push up the leaf spring 34, and the other end is attached to the poppet valve 23, as described above. Is connected to the conical portion 23a. The attraction force between the fixed core 51 and the movable core 52 depends on the cross-sectional area of the center yoke 51a and the cylindrical yoke 51b of the fixed core 51.

A fixed iron core 3 of the solenoid 3 is provided in the circuit chamber 4.
1 is provided with a circuit box 41 fixed by bolts,
In the circuit box 41, a circuit board 42 for controlling the current of the coil 35, and a sensor 43 that is disposed immediately above the upper end surface of the pin 33 fixed to the movable iron core 32 and detects the movement of the pin 33 are provided. ing. The sensor 43 uses a Hall element, a magnetoresistive element, a reed switch, or the like, and is attached to the sensor base 44 so that the position of the permanent magnet 36 provided at the upper end of the pin 33 can be detected. Further, a lead wire connected to the coil 35 is wired to the sensor base 44.

A cover 5 is attached to the upper part of the circuit room 4, and a lead wire 45, one end of which is wired in the circuit room 4 so as to penetrate a part of the cover 5, is connected to an external power source and signal source.

A non-magnetic thin cylindrical connecting pipe 6 is disposed on the outer peripheral surfaces of the solenoid 3 and the movable iron core 32.
The connection pipe 6 is screwed into a male screw formed on the outer peripheral surface of the fixed iron core 31 at the upper part, and a male screw formed on the outer peripheral surface of the valve body 22 of the valve part 2 at the lower part to connect the valve part 2 and the solenoid 3 to each other. Is integrated.

Next, the operation of the control circuit of the solenoid 3 and the operation of the solenoid valve 1 will be described with reference to the block diagram of FIG. 5, the operation diagram of the solenoid valve of FIG. 6, and the timing chart of FIG.

When an ON signal (for example, 5 V) is input to the solenoid ON / OFF terminal, the level switch 61 "starts".
Is output (e.g., 5 V), the signal is input to the comparator 62 and compared with the signal output from the PWM oscillator 63. When the drive circuit 64 outputs “positive” due to the high-level signal, the solenoid coil 35 is applied with a full voltage whose pulse is not width-modulated, and a starting current flows through the coil 35. When a current flows through the coil 35, the movable iron core 32 moves together with the pin 33 into a leaf spring 34.
Is attracted to the fixed iron core 31 side against the urging force, and reaches the position shown in FIG. In this state, the central portion of the diaphragm 24 is moved upward with respect to the outer peripheral portion, and the poppet valve 2
Since the third conical portion 23a releases the fluid passage 27, the fluid enters the valve chamber 21 from the inlet 26 through the passage 27, and flows out of the outlet 28 through the passage 29.

When the movable core 32 is attracted to the fixed core 31, the sensor 43 detects the position of the permanent magnet 36 disposed at the upper end of the pin 33, and at the same time, the sensor 43 outputs an attraction signal ON. When the attraction signal is turned on, a low-level signal voltage (for example, 1 V) of “hold” is output by the level switching unit 61 by the holding current signal 65, and the comparator 6
The pulse width modulated signal is compared with the signal of the PWM oscillator 63 in 2 and sent out to the “positive” of the drive circuit 64. As a result, the coil voltage is output as a narrow pulse, and the coil current is reduced to a holding current having a current value lower than the starting current. The coil will be switched from a high current at start-up to a safe low current with a rise in temperature.

On the other hand, at the same time when the signal of the solenoid ON is issued, the current switching timer 66 is operated. The set time of the timer is set longer than the time during which the movable iron core 32 is attracted to the fixed iron core 31. If the movable iron core 32 is not attracted and the coil current does not drop to the holding current, the protection of the solenoid 3 is prevented. Therefore, the current switching timer 66 serves to switch the coil current to the holding current. Therefore,
The coil current is changed to a narrow pulse voltage by the earlier signal of the signal of the sensor 43 or the signal of the current switching timer 66, and the coil voltage is changed to a narrower pulse voltage by the earlier signal. Of the holding current.

Next, when an OFF signal is input to the solenoid 3, the suction signal is also turned OFF.

Generally, in an iron core that performs overall adsorption as in the present invention, it is necessary to demagnetize it because the residual magnetic attraction force is large. That is, in this case, the reverse excitation timer 6
7, the reverse excitation voltage is output to the solenoid circuit at the same time when the suction signal is turned off. The signal output from the reverse excitation timer 67 is output as "reverse" by the drive circuit 64, and the voltage of the reverse excitation is set for the set time.
Enter 5 Therefore, the movable core 32 and the fixed core 31
The movable magnet core 32 is immediately removed by the urging force of the leaf spring 34, and can be immediately separated from the fixed core 31.

The movable iron core 32 moved downward moves the pin 33 downward, moves the conical portion 23a of the poppet valve 23 connected to the lower end of the pin 33 downward, and closes the passage 27. Therefore, the fluid stops its flow.

Although the above operation has been described using the E-type solenoid, the operation when the flat-type solenoid is used is the same.

[0029]

According to the small solenoid valve of the present invention, the small solenoid valve includes a valve portion having a valve, a solenoid having a fixed iron core and a movable iron core, and a circuit chamber having a circuit board. Is configured.

In addition, a diaphragm is disposed in the hollow portion of the valve portion so as to be divided into an atmosphere chamber on the solenoid side and a valve chamber on the opposite side of the solenoid, and an E-type solenoid or a flat solenoid is used for the solenoid. With
The fixed iron core and the movable iron core are formed so as to have a suction area secured to maintain an appropriate suction force. Therefore, it is possible to provide an electromagnet that is small and has high adsorption efficiency without dust such as abrasion powder discharged from the solenoid being mixed into the fluid without lowering the cleanliness.

The ratio of the total cross-sectional area of the solenoid to the adsorption area between the center yoke of the fixed iron core of the solenoid and the movable iron core is determined based on experimental results to be extremely efficient.
Since it is formed between 0% and 30% (preferably 22% to 26%), a large suction force can be secured even if it is small. In addition, a large force is generated at the time of starting, and when attracted, the current can be switched to a low holding current, so that the solenoid can be protected. Furthermore, in order to reduce the size of this solenoid valve, the circuit chamber is integrated, and the separation of the movable iron core from the fixed iron core is changed from a conventional spiral spring to a leaf spring to reduce the axial space and improve cleanliness. It is configured to use a poppet valve to further increase.

Accordingly, the solenoid valve is small in size, does not lower the cleanness, and can achieve the effect of securing the attraction force.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a solenoid valve according to one embodiment of the present invention.

FIG. 2 is a sectional plan view of a fixed core or a movable core in FIG. 1;

FIG. 3 is a graph showing an adsorption force with respect to an area ratio between an adsorption area of a solenoid and a total cross-sectional area.

FIG. 4 is a diagram showing another embodiment of a solenoid.

FIG. 5 is a block diagram showing a control circuit of the solenoid.

FIG. 6 is a diagram showing the operation of the electromagnet in FIG. 1;

FIG. 7 is a time chart of a control circuit of the solenoid.

FIG. 8 is a sectional view showing a conventional solenoid valve.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Solenoid valve 2 ... Valve part 3 ... Solenoid 4 ... Circuit room 21 ... Hollow part 21a ... Atmosphere chamber 21b ... Valve room 22 ... Valve element 23 ... Poppet valve 24 ... Diaphragm 31, 51 ... Fixed iron core 32, 52 ... Movable iron core 31a, 32a, 51a: Center yokes 31b, 32b, 51b: Cylindrical yokes 33: Pins 34: Leaf springs 35: Coils 43: Sensors

Claims (6)

[Claims] 1. A valve portion including a valve moving in a valve chamber, a valve seat having a fluid passage opening openable and closable by the valve, a fixed core, and a fixed core that can be attracted to the fixed core by excitation of a coil. And a circuit chamber having a circuit board that controls a coil of the solenoid. A hollow part is formed on the solenoid side,
A diaphragm is arranged so as to divide the hollow portion into an air chamber on the solenoid side and a valve chamber on the anti-solenoid side, and the fixed iron core has a substantially E-shaped cross section having a center yoke in a central portion and a cylindrical yoke in a peripheral portion. And the movable iron core is formed in a substantially E-shaped cross section having a center yoke at a central portion and a cylindrical yoke at a peripheral portion, or is formed in a planar shape, and between the center yoke and the cylindrical yoke. Is a pin wound around a coil and disposed on the central axis of the movable iron core of the solenoid so as to penetrate the movable iron core and the fixed iron core, and has one end formed to be connected to the valve. Is fixed, and the center yoke and the cylindrical yoke of the fixed core are formed so as to have a suction area secured to maintain a suction force with the movable core, When the dynamic iron core is released adsorbed, said spring means so as to separate the movable core from the fixed iron core is disposed, the circuit chamber, that the sensor for detecting the adsorption of the moving core is disposed Features a small solenoid valve. 2. The method according to claim 1, wherein a suction area between the center yoke of the fixed core and the movable core is at least 20% to 30% of a sectional area of the solenoid. Item 7. A small solenoid valve according to Item 1. 3. The small solenoid valve according to claim 1, wherein said spring means has a leaf spring. 4. A circuit for switching a coil current to a holding current having a current value lower than a starting current in accordance with a signal confirming that the movable iron core has been attracted by the sensor is provided on the circuit board. The described small solenoid valve. 5. The small solenoid valve according to claim 1, wherein the valve is a poppet valve. 6. The small solenoid valve according to claim 1, wherein a reverse excitation timer for outputting a reverse excitation voltage is provided on the circuit board.