JPS5828074A - Solenoid valve - Google Patents

Abstract

PURPOSE:To reduce the consumed electric-power of a coil by forming the coil for operating a movable iron core from a starting coil and a retention coil and allowing the starting coil to be operated for a short time on starting. CONSTITUTION:The coil for operating a movable iron core is composed of a starting coil SOL.1 and a retention coil SOL.2, which are connected in parallel to power sources 24 and 25. When a solenoid valve is brought into conduction in such a constitutuion, a semiconductor switching circuit Tr1 is brought into conduction for only several m.sec- several hundresth m.sec which is set by a diffeential circuit 21, and the starting coil SOL.1 is excited, while the retention coil SOL.2 is excited during the time in which a current flows in the solenoid. Therefore, a large attractive force is generated during the time when both of the starting coil SOL.1 and the retention coil SOL.2 are excited, so transfer of the movable iron core is not obstructed, and thereafter the movable iron core can be retained by the conduction of the retention coil SOL.2 only.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is used for fluid control of hydraulic machines and other industrial machines such as machine tools and construction machines, and includes fixed iron cores, movable iron cores, and The present invention relates to an improvement in a solenoid valve having a solenoid including a coil arranged to reciprocate a movable iron core, and particularly to an improvement in reducing the power consumed by the solenoid.

There is also a strong demand for low-power solenoid in solenoid valves.

As a countermeasure to this problem, the following methods are usually used: 1) A pilot valve method that uses a small solenoid valve to control the pilot pressure and switch the main pulp 2) Reducing the power consumption of the solenoid by limiting the operating pressure and flow rate. However, the structure is complicated, expensive, easily affected by oil temperature, and maintenance is difficult. In addition, there is a pilot, and the method in item 2) sacrifices the original performance of the valve, so it cannot be said to be a very good method.

One such attempt is a solenoid sold by Oki Electric Industry Co., Ltd. as a "latching solenoid." This solenoid is formed by a starting coil that causes an instantaneous current to flow through the coil, and a holding coil that is a permanent magnet.The solenoid is started by instantly sending current to the starting coil from an external circuit, and the holding current is is not required. However, there are limitations in its use, such as the difficulty of incorporating such a complex circuit into all solenoids.

A solenoid valve used to switch a fluid flow path is made up of a valve body (1) and solenoids provided on both sides of the valve body, as shown in the embodiment shown in FIG. (4) It is fully activated and switches the fluid flow path.

For example, in the solenoid valve shown in Fig. 1, when the solenoid (2) is energized, the movable iron core of the solenoid (2) (
5) is attracted to the fixed iron core (6), and the force is rondo (7).
) to move the spool to the right. At this time, the spring (8) is compressed, and its spring force acts in the opposite direction to the solenoid suction force, and a large fluid reaction force acts at the point where the fluid begins to flow during valve switching.
The solenoid suction force must be greater than the combined force of both spring force and fluid reaction force.

Therefore (apart from the above-mentioned latching solenoid j)
The solenoids used in conventional solenoid valves require a large capacity solenoid to overcome the Δ resultant force of these spring forces and fluid reaction forces.
As a result, the power and current consumed by the solenoid have to increase.

However, the fluid reaction force has the characteristic that it is greatest when the spool begins to open, that is, when the fluid begins to flow, and then rapidly decreases after the spool has been opened for a certain amount of time. Then, the fluid reaction force can be ignored.

Therefore, once the spool is switched by energizing the solenoid, the solenoid only needs to have enough suction force to overcome the spring force to hold the spool, and there is no need to use a large capacity solenoid.

The present invention has been made in consideration of these points, and an object of the present invention is to provide a solenoid valve that consumes less electrical energy, operates accurately, and can shorten the cycle of operation.

Another object of the invention is to provide a solenoid valve that is as easy to handle as conventional solenoid valves and does not require electrical circuitry external to the valve for additional energy savings.

According to the present invention, a solenoid is used for fluid control of hydraulic machines and other industrial machines, and includes a fixed iron core, a movable iron core, and a coil arranged to move the movable iron core, and operates using direct current or alternating current through a rectifier as a power source. In the solenoid valve having a solenoid valve, the coil is formed by a starting coil that attracts the moving iron core and a holding coil that holds the attracted moving iron core in its position, and further, the solenoid actuates the starting coil for a short time. a first semiconductor switch circuit that causes the starting coil to be activated for a short time when current flows through the power source;
The present invention provides a solenoid valve (8) characterized in that the holding coil maintains the entire state of the movable iron core as long as a signal is present.

With this configuration, the solenoid controls the ON-OFF state of the solenoid by switching the current of the power supply, and the state after the solenoid is switched and therefore the spool is switched is that the current flows only to the holding coil, and a small-capacity The position can be held using solenoid power. Therefore, the power consumed by the solenoid has been significantly reduced.

Furthermore, the electric circuit for operating the two coils is built into the solenoid, making it easy to handle.

Furthermore, it does not deteriorate the performance of the solenoid.
The present invention provides an excellent low-power solenoid pulp without degrading the characteristics of the valve, such as switching limit characteristics, switching response time, and internal leakage.

Current holding coil conductor resistance k Rt, number of turns 't""Is
Assuming that the conductor resistance of the starting coil is R2 and the number of turns is k''2, the current flowing immediately after the solenoid is energized, and the electric power magnetomotive force, with the applied voltage being E, are expressed as follows, and when the valve is switched and held, it is expressed as.

Here, the force H□ which generates the suction force necessary to hold the spring by the holding coil may be sufficiently smaller than the magnetomotive force H2 required when switching the entire spool, and therefore the resistance of the holding coil Compared to the resistance R2 of the R+l'I starting coil, RI=(4 to 9) R2(5) can be taken.

Therefore, the power W when holding is the power W when starting. This makes it possible to reduce the power consumption to 115 to 1/10 compared to that of the previous model, and it is possible to maintain the solenoid valve with low power.

In a preferred embodiment of the invention, the starting coil and the holding coil are connected in parallel to the power source, and the first semiconductor switch circuit is connected after the starting coil and in series with the power source. The first semiconductor switch circuit may be connected via a differentiating circuit, and when current flows through the power source, the first semiconductor switch circuit may be in a conductive state for a short time corresponding to a time constant determined by the differentiating circuit. .

In this case, since current initially flows through the starting coil and the holding coil at the same time, a large solenoid attraction force is generated, and the spool is fully actuated to enable switching. = Also, after the spool is switched, current flows only through the holding coil, allowing it to maintain its position with low power. When the current is turned off, no current flows to the holding coil.

In another embodiment of the invention, the starting coil and the holding coil are connected in series with the power supply, and the first semiconductor switch circuit is connected after the starting coil to achieve the same purpose. The holding coil may be connected in parallel and the power source may be connected via the differentiating circuit.

In yet another embodiment of the invention, the starting coil and the holding coil are connected in parallel to the power source, and further K
A CR filter and a second semiconductor switch circuit connected in series thereafter are connected to the power supply in parallel with the starting coil and the holding coil, and the first semiconductor switch circuit is connected after the starting coil and in parallel with the power source. connected in series, and said power source is an integrating circuit and said second circuit connected thereto;
the second semiconductor switch circuit is in a non-conductive state and the first semiconductor switch circuit is in a conductive state when current flows through the power supply. The starting coil and the holding coil are fully actuated, after which the second semiconductor switch circuit is rendered conductive and the first semiconductor switch circuit is rendered non-conductive by a short time delay set by the integrator circuit. only the holding coil is in an activated state;
Further, the holding coil may be deactivated when the current is turned off. Note that the same objective can be achieved even if the njJ excitation starting coil and holding coil are connected in series, and the first semiconductor switch circuit is connected in parallel with the holding coil after the Me starting coil.

With this configuration, even if there is a ripple in the power applied to the solenoid, such as when AC power is rectified by a rectifier, the ripple will flow through the differential circuit and cause the first semiconductor switch to become completely non-conductive. Therefore, it is possible to eliminate the problem of causing the first semiconductor switch to malfunction.

Next, embodiments of the present invention will be described in more detail with reference to the accompanying drawings. The same reference numerals indicate the same members throughout the drawings.

The eleventh example shows all solenoid pulps used in hydraulic machines such as machine tools embodying the present invention. The solenoid valve includes a valve body (1), solenoids (2) (3) provided on both sides of the valve body, and a wiring terminal box (9) provided on the top surface of the valve body. The spool (4), which is arranged in the valve body so that it can reciprocate from side to side, is connected to a solenoid (
2) It is moved via the Rondo (7) by the suction force in (3). Spring (8) <11 is the solenoid (
2) Put the spool (4) in its original position when (3) is cut.
) is arranged to return. As shown for solenoid (2), the solenoid has fixed core (6) and flexible
It includes a coil arranged to move the lr core (5) and the movable core (5). Each component of the solenoid pulp other than the coil and its electric circuit is well known and will not be described in detail here.

In the embodiment of the present invention, the coil divides the given winding space into two parts, a starting coil (170) and a holding coil (1→), and the terminal of each coil is soldered to one end of the solenoid terminal (la). The solenoid terminal (la) can be connected to the terminal holder α31 built into the wiring terminal box (9) in a plug-in manner. The power source is AC via a rectifier (not shown) attached to the inside of the terminal box (9) or the solenoid (2), and the terminal fittings for all external wiring are housed in the inner cover αO. See below for both coils (Figure 2, Figure 4 or Figure 6).
The electrical N path shown in FIGS. 9 to 9) is electrically connected to the terminal fitting and terminal receiver α of the inner lid and is provided on the printed circuit board (lv).

The solenoid of the present application includes an electrical circuit as shown in FIG. 2, FIG. 4"f, or FIGS. 6 to 9. In FIG.
Starting coil (SQL, l) and holding coil (SQL, 2)
is connected in parallel to the power source (c). The starting coil (SQL, l) is connected to the movable iron core (Fig. 1 (5)).
k adsorption, and the holding coil (SQL, 2) is arranged to hold the adsorbed movable iron core in that position. In addition, the solenoid is connected to the positive power supply (c), and when there is current from the power supply, a starting coil (SQL, 1) is activated in response to the current. A circuit (TrI) is provided via a differentiating circuit (c).A semiconductor switch circuit (TrI) is provided via a differential circuit (c).
TrI) is connected in series with it after the starting coil (SOL, 1), and when the solenoid is energized and said current flows, the differentiator circuit (c) sets the number m BeQ~
The semiconductor switch circuit (TrI) remains conductive for several hundred m5ec, and the starting coil (SQL, 1)-2 is conductively excited. The holding coil (SQL, 2) is made conductive and excited while the current is flowing.

In operation, when an external switch (not shown) is turned on and direct current flows through the solenoid, the semiconductor switch circuit (TrI) becomes conductive as shown in Figure 3, and the starting coil (SOT, 1) and Holding coil (SQL
, 2) and 2) simultaneously, a large solenoid attraction force is generated, which attracts the movable iron core and operates the spool to switch. When the movable iron core is attracted and pulled, the first semiconductor switch circuit [Tr1] becomes non-conductive and current flows to the starting coil after a time constant τ0 determined by the differential circuit Qσ of only several msec to several hundred msθC. It disappears. However, the holding coil (SQL, 2) remains in a conductive and excited state as long as the current flows. When the switch is turned OFF and the direct current to the solenoid is cut off, no current flows through the holding coil either, and the solenoid is turned off. In addition, if this occurs,
In Figure 1, for solenoid (2), the spring (
8) returns the spool (4) and movable iron core (5) to their original positions.

FIG. 6 shows a more specific embodiment of the circuit shown in FIG.
In this case, when the solenoid is energized, the base current flows through the capacitor to the base of the transistor Tr', so that the transistor Tr The collector-emitter of ' is in a conductive state, and current flows through the starting coil. However, when the capacitor is charged with the time constant lost by the capacitor C and resistor R, the base current becomes zero and the transistor T
r'1l-j: Since it becomes a non-conducting state, no current flows through the starting coil. It is obvious that such embodiments can be similarly applied to FIG.

The same results as in Fig. 2 can be obtained by connecting the starting coil (SQL, 1) and the holding coil (SQL, 2) to the power source as shown in Fig. 8.
(C) and connected in series to the first semiconductor switch circuit (T
r, ) + connected in parallel with the holding coil (SQL, 2) after the starting coil (SQL, l), and connected to the power supply (c) via a differentiator circuit Q), and when the current flows, for a short time It can also be obtained by making only the current conductive.

However, in the circuits of Figures 2, 6, and 8, if there is a ripple in the power supply applied to the solenoid, for example, if the power supply is an AC power supply rectified by a rectifier, a ripple current will flow through the differential circuit CD. Therefore, the semiconductor switch circuit (Tr, ) cannot become completely non-conductive, and the semiconductor switch circuit may malfunction.

FIG. 4 shows an electrical circuit which overcomes this drawback.

Starting coil (SQL, 1) and holding coil (SQL, 2)
is connected in parallel with the power supply (c), and furthermore, an OR filter (OR) and a second semiconductor switch circuit (Tr2) connected in series are connected in parallel with the starting coil and the holding coil. connected to the power supply so as to bypass it. The first semiconductor switch circuit (Tr, ) is connected in series with the holding coil (SQL, 2) after the holding coil (SQL, 2), and the power supply is connected to the integrating circuit (A) and the second semiconductor switch circuit (Tr2) following it. connected via. Therefore, when the solenoid is turned on, the second semiconductor switch circuit (Tr2) becomes non-conductive and the first semiconductor switch circuit (TrI
) conducts and activates the starting coil (SQL, 1) and the holding coil (SQL, 2), after which there is a short time delay (τ) set by the integrator circuit (A), and the first The second semiconductor switch circuit (Tr23) is made conductive and the first semiconductor switch circuit (TrI) is made non-conductive, the holding coil (SQL, 2) is in the actuated state, and the solenoid is When cut, the holding coil (SQL, 2) is left in the cut state and there is no operation.

In this case, even if there is ripple voltage on the power supplies (c) and (a),
The OR filter and the integration circuit ensure that the second semiconductor switch circuit (Tr2) operates, and the semiconductor switch circuit does not become inoperable due to ripple voltage.

The same result as in Fig. 4 is obtained as shown in Fig. 9, when the starting coil (SOTJ, 1) and the holding coil (SQL, 2) are all connected in series, and the first semiconductor switch circuit (TrI) is activated. It can also be obtained by connecting the holding coil in parallel after the coil.

FIG. 7a shows an exemplary embodiment further embodying the circuit of FIG. In Figure 4, the OR filter is diode D2.
, a resistor R, and a capacitor CI; the integrating circuit @ is formed by a diode D3, a resistor R2, and a capacitor C2; the first semiconductor switch circuit (TrI) is a transistor (Tr'); and the second semiconductor switch The circuit (Tr2) is formed by a Zener diode (BD) and a transistor (Tr"). (DI)
is a diode, (A) is a rectifier, and a capacitor (C3) and a Zener diode (BFi) form an overvoltage (surge pressure) prevention circuit (C).

In operation, the switch (S
When W) is turned on, the input AC voltage is full-wave rectified by the rectifier (A), the holding coil (SQL, 2) is excited at the same time, and after a time delay (τ2), the starting coil (SOT, I
・1) is excited. The shorter this time delay (τ2) is, the better there will be no response delay, but since the transistor (Tr') that drives the starting coil (SQL, 1. is formed by a diode (D2), a resistor (R1), and a capacitor rCt, since it is necessary to apply a full-wave rectified voltage to the base current of the transistor (Tr'), excluding the ripple of the pulsating signal source voltage. (This is due to the inclusion of the 3R filter.)

Next, the purpose of this circuit is to turn off the starting coil after a time (τ1), but the diode (
D3], a resistor (R2), a capacitor (C2), and a Zener diode (FED).
), that is, the voltage that switches Tr' turn ON [
Pressure (VBP2) +T:r-f TL pressure (vz) i
Te, the voltage at point a increases. That time τ, ten τ! Afterwards, the diode (Tr”) turns on (Tr’)
By short-circuiting the O and Sumi pressures and turning off the (Tr') i cut, the current flowing through the starting coil (SQL, 1) is shut off. Note that even if the switch (SW) is turned OFF, there is no discharge path for the electric charge charged in the integrating circuit capacitor (C2), so it does not respond even if the switch is turned on and off continuously, and the electric charge is transferred to (C2) through the diode (D4). This increases the overall responsiveness by discharging the electric charge.

As described above, the present invention is a solenoid valve in which the solenoid coil is made into multiple coils, including a starting coil and a holding coil, and is built into the semiconductor switch circuit Kenrenoid for switching these coils. This resulted in lower power consumption. Furthermore, an excellent cross-power type solenoid valve can be provided without degrading the characteristics of the valve, such as switching limit characteristics, switching response time, and internal leakage.

Although the present invention has been described by way of example with respect to specific embodiments, it will be apparent to those skilled in the art that many changes and modifications may be made without departing from the spirit and scope of the invention. The present invention is intended to include such changes, modifications, and equivalents within the scope of the claims.

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view of a solenoid valve according to an embodiment of the present invention; FIGS. 2, 4, 8, and 9 are electrical circuit diagrams showing different embodiments of the present invention; Figures 3 and 5
6 and 7a are exemplary electrical circuit diagrams more specific to the circuit diagrams in FIGS. 2 and 4, respectively. Figure 7b is 7a
FIG. 3 is a sequence operation diagram of the circuit shown in the figure. 2.3-...Solenoid 5...Movable core 6...Fixed core 14,5OTJ, 1...Starting coil 15
, SQL+, 2 holding coil 21...differentiation circuit 22...
・Integrator circuit 24. ．． 25...Power source Tr1...First semiconductor switch circuit Tr2...Second semiconductor switch circuit agent patent attorney
Junji Kawachi

Claims (1)

[Scope of Claims] (1) A fixed core, a movable core, and a coil arranged to move the movable core, which are used for fluid control of hydraulic machines and other industrial machines and operate using direct current or alternating current via a rectifier as a power source. In the solenoid valve having a solenoid including a solenoid, the coil is formed by a starting coil that attracts the moving iron core, and a holding coil that holds the attracted moving iron core in its position, and the solenoid shortens the starting coil. 1st to operate only for hours
The starting coil is activated for a short time when current flows through the power supply, and the holding coil maintains the state of the movable iron core while the current flows. A solenoid valve characterized by: (2. In the valve according to claim 1, the starting coil and the holding coil are connected in parallel to the power source, and the first semiconductor switch circuit is connected in series with the starting coil after the starting coil. and is connected to the power source via a differentiating circuit, such that when current flows to the power source, the first semiconductor switch circuit is in a conductive state for a short time corresponding to a time constant determined by the differentiating circuit. (3) In the valve according to claim 1, the starting coil and the holding coil are connected in series to the power source, and the first semiconductor A solenoid valve characterized in that a switch circuit is connected in parallel with the holding coil after the starting coil, and connected to the power source via the differential circuit. (4) Claim 1. In the valve described above, the starting coil and the holding coil are connected in parallel to the power source, and an OR filter and a second semiconductor switch circuit connected in series thereafter are connected to the starting coil and the holding coil. The first semiconductor switch circuit is connected to the power source in parallel with the coil, and the first semiconductor switch circuit is connected in series with the starting coil after the starting coil, and is connected to the power source through an integrating circuit and the second semiconductor switch circuit following the starting coil. is connected, and when current flows through the power supply,
the second semiconductor switch circuit is rendered non-conductive and the first semiconductor switch circuit is rendered conductive to actuate the starting and holding coils, followed by a short time delay set by the integrator circuit; The second semiconductor switch circuit is in a conducting state and the first semiconductor switch circuit is in a non-conducting state, so that only the front self-holding coil is activated, and when the current is cut off, the holding coil is activated. A solenoid valve that is characterized by no operation. (5) Permissible range of claims 1. In the valve according to claim 1, the starting coil and the holding coil are connected in series to the power source, and the OR filter and the second coil are connected in series. a semiconductor switch circuit is connected to the power source in parallel with the starting coil and the holding coil; the first semiconductor switch circuit is connected in parallel with the holding coil after the starting coil; and the first semiconductor switch circuit is connected in parallel with the holding coil after the starting coil; The second semiconductor switch circuit is connected through an integrating circuit and the second semiconductor switch circuit following it, and when current flows to the power source, the second semiconductor switch circuit is in a non-conducting state and the first semiconductor switch circuit is in a non-conducting state. is made conductive to actuate the starting coil and the holding coil;
Thereafter, a short time delay set by the integrator circuit causes the second semiconductor switch circuit to become conductive and the first semiconductor switch circuit to become non-conductive, leaving only the holding coil activated. Furthermore, the solenoid valve is characterized in that when the current is cut off, the holding coil ceases to operate. (6) The valve according to claim 2 or 3, wherein the first semiconductor switch circuit is a transistor, and the differentiator circuit is a solenoid valve comprising a capacitor, a resistor, and a diode. . (7) In the valve according to claim 4, the OR filter is formed of a diode, a resistor, and a capacitor, the integrating circuit is formed of a diode resistor and a capacitor, and the first semiconductor switch circuit is formed of a transistor. , and the second semiconductor switch circuit is formed of a Zener diode and a transistor, respectively.