JP2000205444A - Solenoid valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain impact noise accompanying reciprocal motion of a plunger of a solenoid valve. SOLUTION: A cylindrical recessed part 21 or a columnar protruded part is formed at a portion facing against a plunger 3 of an aspirator 2, a columnar protruded part 31 or a cylindrical recessed part is formed at a portion facing against the aspirator of the plunger, the protruded part is fitted in the recessed part with a play through an air gap, series circuits of a capacitor and a register are connected to an exciting coil 10 in parallel, and the exciting coil is connected to an alternating current electric power source 31 through a rectification circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solenoid valve, and more particularly, to a solenoid valve having a spherical valve body at the tip of a plunger to improve noise reduction.

[0002]

2. Description of the Related Art For example, an electromagnetic valve is often used for switching a circuit of a refrigerant circuit, and a solenoid valve having a relatively large valve opening stroke is employed. That is,
In this type of solenoid valve, a plunger is housed in a sleeve so as to be able to reciprocate freely, and an exciting coil is externally provided.
While energizing the excitation coil excites the attraction element, the plunger is attracted and the spherical valve element at the tip of the plunger is released from the valve seat. The valve element is caused to return by the biasing force of (1) to seat the spherical valve body at the tip of the plunger on the valve seat, thereby performing the valve action.

The suction element is fitted to the rear end of the sleeve and fixedly sealed by means such as TIG welding, and a housing for covering the exciting coil is fixed to the upper end of the suction element by screws. . A valve seat base having a valve seat is fitted to the distal end side of the sleeve, and is fixedly sealed by means such as brazing, and a pipe constituting an inlet and an outlet of a refrigerant is attached to the valve seat base. I have. Concave portions are formed on the distal end surface of the suction element and the rear end surface of the plunger, respectively, and a coil spring is contracted between the concave portions to bias the plunger.

In the conventional solenoid valve configured as described above, when an excitation coil fixed to the outside of the sleeve is energized, the plunger is attracted against the spring force of the coil spring, and the spherical valve element is detached from the valve seat. When the flow passage is opened and the energization to the electromagnetic coil is cut off, the plunger is urged by the spring force of the coil spring, and the spherical valve element is seated on the valve seat to close the flow passage. .

[0005]

However, in the conventional solenoid valve, the plunger and the attraction element abut when energizing the exciting coil, and the spherical valve element at the tip of the plunger and the valve seat abut when the energizing coil is energized. Since the suction element and the spherical valve element are generally made of a metal material, there is a problem that unpleasant impact noise is generated at the time of collision.

An object of the present invention is to solve the above-mentioned problems and to provide an electromagnetic valve which suppresses impact noise generated between a plunger and a suction element and between a valve body and a valve seat.

[0007]

Therefore, the solenoid valve according to the present invention is provided with a suction element at the rear end of the sleeve and a valve seat at the front end of the sleeve, and a plunger is provided in the sleeve between the suction element and the valve seat. Is reciprocally accommodated, and when the excitation coil is energized, the plunger is attracted by the magnetic attraction of the attraction element to separate the valve element at the tip of the plunger from the valve seat, while the biasing force of the coil spring is applied when the excitation coil is de-energized. In the solenoid valve, the plunger is moved backward toward the valve seat, and the valve body is seated on the valve seat. In the solenoid valve, a cylindrical concave portion is formed at a portion of the suction element facing the plunger, and the plunger is sucked. While a column-shaped convex portion is loosely fitted in the concave portion through an air gap between the two in the portion facing the child,
A series circuit of a capacitor and a resistor is connected to the exciting coil in parallel, and the exciting coil is connected to an AC power supply via a rectifier circuit.

In the solenoid valve according to the present invention, a suction element is provided at the rear end of the sleeve and a valve seat is provided at the front end of the sleeve, and the plunger is reciprocally housed in the sleeve between the suction element and the valve seat. When the excitation coil is energized, the plunger is attracted by the magnetic force of the attraction element to separate the valve body at the tip of the plunger from the valve seat, and when the excitation coil is de-energized, the plunger is moved to the valve seat by the biasing force of the coil spring. In the solenoid valve, the valve body is seated on the valve seat, and a columnar convex portion is formed at a portion of the suction element facing the plunger, and at a portion of the plunger facing the suction element. A cylindrical concave portion which is loosely fitted between the two via an air gap is formed outside the convex portion, and a series circuit of a capacitor and a resistor is connected to the exciting coil in parallel. Encouragement Coil, characterized in that it is connected to an AC power source through a rectifier circuit.

One of the features of the present invention is that a cylindrical concave portion or a columnar convex portion is formed on the suction element, and a columnar convex portion or a cylindrical concave portion is formed on the plunger. The present invention is characterized in that, while being loosely fitted to the columnar projection via an air gap, a series circuit of a capacitor and a resistor is connected in parallel to the excitation coil, and the excitation coil is connected to an AC power supply via a rectifier circuit. In such a configuration, the current flowing into the capacitor when the excitation coil is energized can be limited to a size corresponding to the size of the power supply, and the time constant of the discharge current when the current of the excitation coil is cut off can be selected as appropriate. A current having a waveform that rises at a desired change rate at the start of energization and converges to a predetermined current value at the start of energization, and falls at a desired change rate at the end of energization and converges to a current value of zero. Can be supplied to the exciting coil.

As a result, a sudden change in the current flowing through the exciting coil at the end of the forward and backward movements of the plunger is gradually reduced, so that the forward and backward movements of the plunger become gradual. Abutment between the needle and the suction element can be suppressed, and the generation of impact noise can be reduced, thereby improving quietness.

When a diode or a zener diode having a cathode on the positive electrode side and an anode on the negative electrode side is connected in parallel to the rectifier circuit, the back electromotive force generated when the power supply to the exciting coil is cut off is returned to the diode. As a result, it is possible to prevent a large voltage that may damage the capacitor from being generated.

Further, since the capacitor, resistor, diode, and rectifier circuit have a small number of components as a whole and can be incorporated in a relatively small space, if all or a part thereof is integrally formed with the valve assembly, a conventional structure is required. A solenoid valve with high noise reduction can be provided without changing the control device.

Further, when all or a part of the capacitor, the resistor, the diode, and the rectifier circuit are included in the control device for driving the valve, an electromagnetic valve having a high noise level can be provided without largely changing the valve assembly. it can. As a result, it is possible to provide a highly silent air conditioner by changing only the valve assembly or the control device.

[0014]

According to the present invention, a structure in which a suction element having a cylindrical concave portion or a columnar convex portion is combined with a plunger having a columnar convex portion or a cylindrical concave portion, and the capacitor and Since the series circuit of the resistor is connected in parallel with the exciting coil, the current flowing into the capacitor when the exciting coil is energized is limited to the size corresponding to the size of the power supply, and the current of the exciting coil is cut off. The time constant of the discharge current at the time can be appropriately selected to select the current change at the falling portion of the current, and the exciting coil rises at a desired change rate at the start of energization, converges to a predetermined current value, and at the time of energization stop. A current having a waveform that falls at a rate of change of and converges to a current value of zero can flow.

As a result, when the excitation coil is energized, the attraction force of the attraction element and the spring force of the spring can be balanced, and the plunger and the attraction element do not substantially collide even when the rise of current is not controlled. it can. On the other hand,
When the power to the excitation coil is cut off, the current flowing through the excitation coil gradually decreases, thereby suppressing acceleration of the plunger caused by the spring force of the spring member, and allowing the valve body and the valve seat to gently abut.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to specific examples shown in the drawings. FIG. 1 is a diagram showing a structural example of a preferred embodiment of an electromagnetic valve according to the present invention, FIG. 2 is a diagram showing a structural example of a capacitor built-in portion in the above embodiment, and FIG. 3 is a control device for driving the valve in the above embodiment. FIG. 4 is a diagram showing another circuit configuration example of the control device, and FIG.
FIG. 5 is a diagram showing still another circuit configuration example of the control device, FIG. 6 is a diagram showing a circuit configuration example of the control device in another embodiment,
7 is a diagram showing a structural example of a conventional solenoid valve, FIG. 8 is a diagram showing a structural example of a solenoid valve to which the present invention is applied, FIG. 9 is a diagram showing a circuit configuration example of a control device in the conventional solenoid valve, FIG. 10 is a diagram showing a circuit for energizing and shutting off the exciting coil of the solenoid valve, FIG. 11 is a diagram for explaining the relationship between the time change of the current and the lift amount of the plunger, and FIG. FIG. 13 is a diagram showing a circuit used to observe the relationship between the force and the spring force, FIG. 13 is a diagram showing the relationship between the attraction force of the plunger and the spring force in the conventional solenoid valve, and FIG. 14 is the attraction of the plunger in the solenoid valve of the present invention. FIG. 1 shows a relationship between a force and a spring force.
5 is a diagram showing a transient current waveform at the time of energization / interruption, FIG. 16 is a diagram showing a relationship between a current waveform when an alternating current is applied to the excitation coil and a change in attraction force acting on the plunger, and FIG. 17 is an excitation coil FIG. 6 is a diagram showing a relationship between a current waveform when an AC current is rectified and energized and a change in a suction force acting on a plunger.

First, in order to facilitate understanding of the present invention, the structure of a conventional solenoid valve of this type will be described. In FIG. 7, a solenoid valve 100 includes a valve assembly (hereinafter, referred to as a valve ASSY) 1
Excitation coil 10 covered by housing 11 around 9
And the cover 11 is screwed to the valve ASSY1
9 is fixed to the suction element 2. In the figure,
Reference numeral 14 denotes a lead wire of the exciting coil 10.

In the valve ASSY 19, a sleeve 1 having a cylindrical shape is used.
The suction element 2 is inserted into an upper half portion of the suction element 2 and fixed by means such as TIG welding, and a concave portion is formed on a distal end surface of the suction element 2. A plunger 3 is reciprocally inserted into the lower half of the sleeve 1, and a recess is formed on the rear end surface of the plunger 3 so as to face the recess of the suction element 2, and between the suction element 2 and the plunger 3. A coil spring (spring member) 5 is housed in the recess, and a spherical valve body 4 is rotatably attached to the tip of the plunger 3.

A cylindrical portion of the valve seat base 6 is fitted to the lower end of the sleeve 1 and fixed by brazing or the like, and a valve is provided on the bottom of the valve seat base 6 in cooperation with the spherical valve element 4. A valve seat 7 forming a mechanism is formed, and a refrigerant inflow pipe 8 forming a refrigerant inlet at a cylindrical portion of the valve base 6 and a refrigerant forming a refrigerant outlet below the valve seat 7 at the bottom. Outflow pipe 9
Are fixed by means such as brazing.

FIG. 9 shows a circuit configuration including a control device for driving the solenoid valve 100 by supplying a current to the exciting coil 10 and cutting off the supply of current. In the figure, 41 is a printed circuit board,
Reference numeral 42 denotes a drive signal circuit unit, and reference numeral 43 denotes an output circuit unit having switch means for connecting and disconnecting the exciting coil 10.

Next, the operation of the plunger 3 when the excitation coil 10 is energized from an AC power supply will be described with reference to FIG. FIG. 16 shows the relationship between the alternating current and the attractive force of the plunger 3. In the figure, the symbol M indicates the waveform of the current flowing through the exciting coil 10, and the symbol N indicates the change in the attractive force generated by this current. Since the suction force has an alternating waveform between the maximum value and the minimum value of zero, the spherical valve body 4 can be maintained during energization as it is.
Cannot be put into contact with or separated from the valve seat 7 and cannot be used practically. Therefore, as shown in FIG. 7, a short ring 022 is provided on the suction element 2,
The change in the attraction force is smoothed as shown by the symbol P in FIG. 16 to such an extent that it can be regarded as substantially equivalent to the application of a direct current, and the spherical valve body 4 and the valve seat 7 are connected to the exciting coil. The contact and separation are made in response to energization and cutoff of the power supply 10.

The present invention relates to an electromagnetic valve used for an AC power supply. It is considered that the suction force acting on the suction element 2 is sufficiently smoothed and exhibits the same behavior as when a DC current is supplied. Proceed with explanation.

When the switch 23 is closed and the excitation coil 10 is energized in the circuit configuration shown in FIG. 10, the suction element 2, the plunger 3 and the housing 1 are turned on as shown by an arrow A in FIG.
1 constitutes a magnetic circuit, and a magnetic flux is generated. When a magnetic flux is generated, the attracting element 2 is excited, and the attracting element 2 and the plunger 3
Between the coil spring 5 and the coil spring 5
Of the valve seat 7 against the spring force of
Is separated from the valve seat 7, and the refrigerant flows from the inflow pipe 8 to the outflow pipe 9. At this time, since both the suction element 2 and the plunger 3 are made of an iron-based metal, a large impact noise is generated, and metal wear powder is generated at the abutting portion.

Next, the switch 23 of the circuit shown in FIG.
When the power supply to the excitation coil 10 is interrupted by opening the magnetic flux, the magnetic flux disappears, and hence the attraction force disappears.
Is biased by the spring force of the coil spring 5 and moves back toward the valve seat 7, the spherical valve body 4 is seated on the valve seat 7, and the flow of the refrigerant is shut off. At this time, since the spherical valve body 4 and the valve seat 7 are both made of a metal material, a large impact noise is generated.

Next, the behavior of the conventional solenoid valve will be described in detail. In the conventional structure, both opposing end faces of the suction element 2 and the plunger 3 are formed in a flat shape (hereinafter, referred to as a flat type). In such a structure, as the lift amount increases, the gap between the suction element 2 and both end faces of the plunger 3 decreases, the magnetic flux density increases, the suction force increases, and the lift is regulated when the both end faces come into contact. This structure is a mechanism selected when it is desired to guarantee a certain suction force at the position of the maximum lift. On the other hand, since the magnetic flux density is maximized in the contact state, a large force is applied to the suction element 2 and the plunger 3. If the residual magnetism remains and the current is cut off and the current flowing through the exciting coil 10 does not become considerably small, the plunger 3 does not separate from the attraction element 2.

FIG. 8 shows that a cylindrical convex portion 021 is formed on the suction element 2 and a cylindrical concave portion 031 is formed on the plunger 3.
A structure (hereinafter, referred to as a cylindrical structure) to which the present invention is applied so as to be loosely fitted to a cylindrical convex portion 021 through a circumferential air gap is shown. 8 and 7 are the same with respect to the reciprocating movement of the attraction / separation in response to the energization / interruption of the exciting coil 10, but the movement distance of the plunger 3, ie, the attraction force to the lift. There are differences in trends.

That is, in the cylindrical structure, when the lift amount increases, the circumferentially opposing area of the convex portion 021 and the concave portion 031 increases, and the magnetic flux density decreases. The suction power decreases. While the spherical valve element 4 is surely separated, the suction force of the plunger 3 rapidly decreases as the lift amount increases.
By selecting a spring constant that balances the suction force acting on the plunger 3 with the spring force of the coil spring 5 before the suction element 2 and the suction element 2 collide, the collision between the plunger 3 and the suction element 2 can be avoided.

FIG. 11 shows the state of the current flowing through the exciting coil 10 and the change in the lift amount according to the change in the current when the exciting coil is energized and cut off by the circuit shown in FIG. When the excitation coil 10 is energized, the current gradually increases in accordance with the time constant due to the inductance of the excitation coil 10, and when the current is cut off, the current substantially decreases due to the arc of the switch 32.
When the current is increased, the current is at the position indicated by B1 in the planar solenoid valve, and at the position indicated by B2 in the cylindrical structure, the attraction force overcomes the spring force, while when the current is decreased, it is indicated by C1 in the planar structure. In the cylindrical structure, the spring constant of the coil spring 5 and the air gap between the attraction element 2 and the plunger 3 can be appropriately set at the position indicated by C2 in the cylindrical structure so that the spring force overcomes the attraction force. .

On the other hand, looking at the lift amount, in the planar structure, when energized, the attracting force by the exciting current starts to move from the position B1 where the spring force exceeds the spring force, and the attracting force increases with the increase in the lift. The characteristic shown by the curve D1 is obtained. When the current is cut off, the spring force is accelerated by the spring force at the position C1 exceeding the attractive force including the influence of the residual magnetic flux, and the characteristic shown by the curve E1 is obtained. In the cylindrical structure, the attraction force is large at the position where the lift amount is small, and the attraction force decreases with the increase of the lift amount. Therefore, the characteristic shown by the curve D2 is obtained. Reversion starts at a relatively early point in time, resulting in the characteristic shown by curve E2.

In the non-energized region shown in FIG. 11, the plunger has, for example, a suction force of about 1 due to a damping current in a planar structure.
At the time when the light is substantially extinguished in milliseconds, the lift is accelerated by the spring force and the lift is zero in about 5 milliseconds, that is, the spherical valve element 4 is moved to the valve seat 7.
To generate impact noise. In the case of the cylindrical structure, the plunger starts moving backward, so that the plunger is affected by the attraction force due to the damping current. However, the spherical valve body 4 abuts the valve seat 7 at a speed sufficient to generate impact noise.

The present invention focuses on the fact that the plunger 3 starts moving when the attractive force generated by the current flowing through the exciting coil 10 coincides with the spring force in the cylindrical solenoid valve structure. It was made by observing the phenomenon of initiation. FIG. 12 is a circuit for gradually increasing or decreasing the current so as not to be substantially affected by the circuit time constant. Reference numeral 31 denotes a power supply, 32 denotes a switch, and 33 denotes a variable resistor.

FIGS. 13 and 14 show the circuit shown in FIG. 12 in which the current is increased or decreased.
The relationship between the lift amount, the suction force of the plunger 3 and the spring force of the coil spring 5 is obtained. FIG. 13 shows an example of a plunger having a planar structure. In the figure, F1 is a coil spring 5
G11 indicates an attraction force for a current such that the plunger 3 is attracted to the attraction element 2, and G13 indicates an attraction force for a current at which the plunger 3 is separated from the attraction element 2. The attraction force G13 at the time of separation is considerably lower than the spring force F1, but this is due to the effect of residual magnetism. When the current is reduced at the position of the maximum lift X, the plunger 3 starts to return, but once the plunger 3 starts moving, the spring force always exceeds the suction force, so that the lift zero point is reached as it is. .

FIG. 14 shows an example of a plunger having a cylindrical structure. In the figure, F2 is the spring force of the coil spring 5, G21
Is the attractive force for the maximum current of the product design value, and G22 is G2
G23 indicates an attractive force for a current smaller than 1, and G23 indicates an attractive force for a current smaller than G22. If the current is reduced at the point of the maximum lift amount X1, the plunger 3 starts to return at a position where the suction force matches the spring force.
If the current is maintained, the plunger 3 remains stopped. When the current is gradually reduced from this state, the plunger 3 also moves slowly. Since the residual magnetism is small, it is ignored, and when the current for the characteristic G21 decreases to the current for the characteristic G22, the plunger 3 moves to the position of X2. When the current decreases for the characteristic G23, the plunger 3 moves to the position of X3.

According to the above observation results, the plunger having the planar structure cannot be held at a specific lift position by controlling the current value, whereas the plunger having the cylindrical structure cannot control an arbitrary lift position by controlling the current value. It was found that it could be held in position.

FIG. 15 shows a state in which the current flowing through the excitation coil 10 increases and decreases when the excitation coil 10 is energized and the energization is cut off. H indicates the characteristic at the time of energization according to the time constant of the inductance of the excitation coil 10, and I indicates the characteristic. Characteristics when de-energized,
J is the characteristic of a large time constant obtained by the present invention when not energized,
K indicates a charging characteristic flowing through the capacitor 23. Since the plunger 3 moves slowly according to this characteristic curve at the time of the return movement, the abutment between the valve body 4 and the valve seat 7 is reduced to a level that does not substantially matter.

1 to 3 show a preferred embodiment of a solenoid valve according to the present invention. 1 and 2, the same reference numerals as those in FIG. 8 indicate the same or corresponding parts. An operation suppressing unit 29 is fixed to the housing 11 of the exciting coil 10. In the operation suppressing unit 29, a printed circuit board 22 having a suppressing circuit is built in the case 21, and the suppressing circuit increases the time constant of the current flowing through the exciting coil 10 so as to suppress the operating speed of the plunger 3. Has become.

The case 21 has a mounting hole 211 formed therein.
The mounting screw 27 is inserted through the mounting hole 211 so that the housing 1
1 is screwed into the housing 21 so that the housing 11
It is fixed to. The case 21 is provided with a male connector 28 having a terminal 281 and is connected to the female connector 13 provided on the exciting coil 10 to form an electric circuit. 14 is a lead wire connected to a power supply or a control device.

In this embodiment, the operation suppressing portion 29 is connected to the housing 11.
However, it may be formed integrally with the excitation coil 10 or may be formed in a cylindrical shape and fixed to the excitation coil 10 in tandem. Various methods of integrally configuring the solenoid valve are conceivable. However, as with the conventional solenoid valve, any configuration may be used as long as the lead wire 14 is connected to a power supply or a control device and functions as an independent solenoid valve. .

FIG. 3 shows a specific implementation circuit of the operation suppressing section 29. In this example, a series circuit of the capacitor 23 and the resistor 24 is connected in parallel with the exciting coil 10, and the exciting coil 10 is connected between the positive electrode 261 and the negative electrode 262 of the full-wave rectifier circuit 26. A surge absorption diode (which may be a Zener diode) 25 is connected in parallel to the series circuit. The diode 25 circulates back electromotive force induced in the coil 10 when the switch 32 is opened, and is connected to the capacitor 23. A reverse voltage is prevented from being applied. The diode 25 has a similar function when the rectifier circuit 26 performs full-wave rectification, and thus can be omitted. As the capacitor 23, an electrolytic capacitor having a relatively large capacity, a double tank capacitor, or the like is appropriately selected.

In FIG. 3, when the switch 32 is opened, the current stored in the capacitor 23 is
The discharge is performed in accordance with a time constant determined by the capacity of No. 3, the resistance of the resistor 24, and the inductance of the exciting coil 10. The plunger 3 moves backward in response to the gradual change in the discharge current, so that when the spherical valve body 4 is seated on the valve seat 7 with zero lift, the plunger 3 is seated quietly and smoothly, and the impact noise is reduced. .

FIG. 4 shows a modification of the circuit of the operation suppressing section 29. In this example, a half-wave rectifier circuit 26 is used instead of the full-wave rectifier circuit.

FIG. 5 shows still another modification of the circuit of the operation suppressing section 29. In this example, a difference is provided between the current for charging the capacitor 23 and the current for discharging. That is, during charging, the charging current flowing to the capacitor 23 via the diode 251 and the resistor 241 is limited in consideration of the capacity of the power supply 31, while the discharging is selected by appropriately selecting the resistor 242. Allows for different time constants. The full-wave rectifier circuit 26 may be replaced with a half-wave rectifier circuit.

FIG. 17 shows the waveform of the current flowing through the exciting coil 10 and the change in the attractive force acting on the plunger 3 when the rectifier circuit is provided. The symbol Q is a full-wave rectified waveform, the symbol Q ′ is an approximate waveform obtained by taking the first term of the Fourier expansion of the full-wave rectified waveform Q,
Symbol R denotes a change in suction force generated in the suction element 2, and S denotes a change in suction force smoothed by the operation of the short ring 22 shown in FIG. Current Q compared to the conventional case without rectification
(Or Q ') has a DC component and the alternating frequency is doubled, so that the degree of smoothing of the pulsating flow is improved.

FIG. 6 shows another embodiment of the present invention. In the figure, reference numeral 200 denotes a control circuit for driving the solenoid valve 100;
1 is a printed circuit board, 42 is a drive signal circuit section, 43 is an output circuit section, and 44 is an operation suppressing section. In this example, the solenoid valve 10
The zero valve ASSY 19 can provide an air-conditioning system with high quietness without changing the conventional.

[Brief description of the drawings]

FIG. 1 is a view showing a structure of a first embodiment of a solenoid valve according to the present invention.

FIG. 2 is a diagram illustrating a structural example of a capacitor built-in portion in the embodiment.

FIG. 3 is a diagram illustrating a configuration example of a control circuit in the embodiment.

FIG. 4 is a diagram illustrating another configuration example of the control circuit.

FIG. 5 is a diagram showing still another configuration example of the control circuit.

FIG. 6 is a circuit configuration diagram showing another embodiment of the present invention.

FIG. 7 is a view showing a structural example of a conventional solenoid valve.

FIG. 8 is a diagram showing a structure of a solenoid valve to which the present invention is applied.

FIG. 9 is a circuit diagram of a control device in a conventional solenoid valve.

FIG. 10 is a circuit diagram for supplying a current to an exciting coil in a conventional solenoid valve and cutting off the current.

FIG. 11 is a diagram for explaining a relationship between a time change of a current and a lift amount of a plunger.

FIG. 12 is a circuit diagram for checking the relationship between the attraction force and the spring force of the plunger by changing the current flowing through the excitation coil of the solenoid valve.

FIG. 13 is a diagram illustrating a relationship between a suction force of a plunger and a spring force in an electromagnetic valve having a conventional structure.

FIG. 14 is a diagram illustrating a relationship between a suction force and a spring force of a plunger in the solenoid valve according to the present invention.

FIG. 15 is a diagram showing a relationship between a transient current waveform at the time of energization / interruption and operating characteristics of a plunger.

FIG. 16 is a diagram showing a relationship between a current waveform when an alternating current is applied to an exciting coil and a change in an attractive force acting on a plunger in a conventional solenoid valve.

FIG. 17 is a diagram showing a relationship between a current waveform when an AC current is rectified and supplied to an exciting coil and a change in an attractive force acting on a plunger in the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sleeve 2 Attractor 021 Cylindrical concave part 022 Short ring 3 Plunger 031 Cylindrical convex part 4 Spherical valve element 5 Coil spring (spring member) 7 Valve seat 23 Capacitor 24 Register 241, 242 Register 25 Diode 26 Rectifier circuit 31 AC power supply

Claims (5)

[Claims] An attraction element is provided at a rear end side of a sleeve, and a valve seat is provided at a tip end side of the sleeve. A plunger is reciprocally accommodated in a sleeve between the attraction element and the valve seat. The plunger is attracted by the magnetic force of the attracting element to separate the valve body at the tip of the plunger from the valve seat, and when the energizing coil is de-energized, the plunger is moved back toward the valve seat by the urging force of the coil spring. A cylindrical recess is formed in a portion of the suction element facing the plunger, and a portion of the plunger facing the suction element is provided in the recess between the two. A column-shaped convex portion that is loosely fitted through an air gap is formed in the excitation coil, a series circuit of a capacitor and a resistor is connected in parallel to the excitation coil, and the excitation coil is Solenoid valve, characterized in that it is connected to a source. 2. A suction element is provided at a rear end side of a sleeve and a valve seat is provided at a tip end side of the sleeve. A plunger is reciprocally accommodated in a sleeve between the suction element and the valve seat. The plunger is attracted by the magnetic force of the attracting element to separate the valve body at the tip of the plunger from the valve seat, and when the energizing coil is de-energized, the plunger is moved back toward the valve seat by the urging force of the coil spring. In a solenoid valve configured to be seated on a valve seat, a columnar convex portion is formed at a portion of the attraction element facing the plunger, and both at a portion of the plunger facing the attraction element outside the projection. A cylindrical concave portion that is loosely fitted through an air gap is formed between the exciting coil and a series circuit of a capacitor and a resistor is connected in parallel to the exciting coil, and the exciting coil is connected to the exciting coil via a rectifier circuit. Solenoid valve, characterized in that it is connected to a flow source. 3. The solenoid valve according to claim 1, wherein a diode or a Zener diode having a cathode on the positive side of the rectifier circuit is connected to the exciting coil in parallel. 4. The solenoid valve according to claim 1, wherein all or part of the capacitor, the resistor, the diode, and the rectifier circuit are integrally formed with a valve assembly. 5. The solenoid valve according to claim 1, wherein all or part of the capacitor, the resistor, the diode, and the rectifier circuit are included in a control device that drives the valve.