JPH0362952B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a solenoid valve used in hydraulic equipment, etc., and more specifically, the present invention relates to a solenoid valve used in hydraulic equipment, etc. The present invention relates to an improvement in the operation display method of a current signal operated solenoid valve that controls energization and deenergization of a solenoid via a switching element.

[Conventional technology]

For example, Japanese Patent Application Laid-Open No. 59-1980 describes that by controlling the opening and closing of solenoid valves based on optical signals, electrical noise and electromagnetic induction interference (EMI) can be removed, and compatibility with computer control systems can be improved.
This is known from, for example, Japanese Patent No. 58283.

However, in principle, it is possible to control a switching element using an optical signal sent through an optical fiber as a signal line, and use this to control the excitation of a solenoid plunger device of a solenoid valve, but in practice, In order to prevent vibrations during operation of the solenoid valve, dirt in the environment around the solenoid valve, etc., it is necessary to take considerable measures to connect the optical fiber and the solenoid valve's electrical equipment.

In addition, this type of solenoid valve uses a lamp (or light emitting diode) connected in parallel with the solenoid coil to indicate the operation of the solenoid valve.
Excess current flows through the switching element for the amount of current flowing through the lamp, increasing the amount of heat generated.Also, even if the lamp lights up, current does not necessarily flow through the solenoid coil, and the plug of the solenoid coil may be incomplete. Even if the coil was hot or the coil was disconnected, the lamp would still light up, and it did not completely fulfill its original role of indicating that the coil was energized.

[Problem that the invention seeks to solve]

The main object of the present invention is to separate the solenoid excitation on/off control signal from the solenoid excitation power source and send it via normal electrical wiring without using optical fiber as the signal line. In addition to making it less susceptible to the influence of electrical noise when turning on and off the solenoid coil, and making it less likely that EMI due to the noise in the power line is applied to peripheral equipment via the signal line, the solenoid coil can be used without using a lamp in parallel with the solenoid coil An object of the present invention is to provide a current signal operated solenoid valve equipped with a display means that allows confirmation of energization.

Another object of the present invention, in addition to the above-mentioned main object, is to provide an electromagnetic valve having solenoid devices on both sides of the valve body, so that the operation display can also serve as a display for each flow direction of the solenoid device. The present invention provides the current signal operated solenoid valve.

[Means for solving problems]

According to the present invention, in order to achieve the above-mentioned main problem, a series circuit of a solenoid coil and a switching element is connected between a pair of excitation power supply terminals, and the switching element is separated from the current flowing through the solenoid coil. a control circuit that performs switching control according to on/off of another input signal current input to the control circuit; a first display light emitting diode that lights up according to the input signal current to the control circuit; and a closed loop with the solenoid coil. There is also provided a current signal operated solenoid valve characterized in that it further comprises a second display diode that is lit by a back electromotive force generated from the solenoid coil when the switching element is cut off.

In one operation, the first and second display light emitting diodes have different colors,
Although separate elements may be used as these light emitting diodes, it is preferable that the first and second display light emitting diodes have two anode electrodes, a first and a second, and a common cathode electrode. When using a light emitting diode as a single element which has It can be configured with a compact structure and simple external design.

In another embodiment, the control circuit includes a photocoupler device, the input side of the photocoupler device being connected to a DC signal power source via switching means for producing an on/off contact signal, the switching output signal of the photocoupler device causing the switching element to is designed to be conductive or cut off.

According to the present invention, in order to achieve the other object, a first series circuit of a first solenoid coil and a first switching element connected between the output terminals of the excitation power source; a first control circuit that controls switching according to on/off of a separate first input signal current separated from the current flowing through the first solenoid coil; A first display light emitting diode lit by a first input signal current forms a closed loop with the first solenoid coil and generates a back electromotive force from the first solenoid coil when the first switching element is cut off. a second series circuit including a second display light emitting diode that is lit by electric power, a second solenoid coil and a second switching element connected between the output terminals of the excitation power source; a second control circuit that controls switching according to on/off of a separate second input signal current separated from the current flowing through the second solenoid coil; a third display light emitting diode that lights up in response to the second input signal current; and a third display light emitting diode that forms a closed loop with the second solenoid coil and generates a back electromotive force from the second solenoid coil when the second switching element is cut off. a fourth display light emitting diode that is lit by a light emitting diode, the first and third display light emitting diodes are of different colors, and the second and fourth display light emitting diodes are different from each other. A current signal operated solenoid valve is provided which is characterized by being colored.

In this case, in one embodiment, the first and fourth display light emitting diodes emit the same color, and the second and third display light emitting diodes emit the same color.

Also in this case, as the first and second display light emitting diodes or the third and fourth display light emitting diodes, the first and second display light emitting diodes can be used as the first and second display light emitting diodes.
It has two anode electrodes and one common cathode electrode, and produces different colors when current flows from the first anode electrode to the common cathode electrode and when current flows from the second anode electrode to the common cathode electrode. A light emitting diode can be used as a single element that emits light.

Furthermore, according to another aspect of this case, the first
and a second control circuit each including a photocoupler device, the input side of each photocoupler device being connected to a DC signal power source via first and second switching means for producing an on/off contact signal, and controlling the switching of the respective photocoupler device. The output signals cause the corresponding switching elements to become conductive or disconnected, respectively.

[Effect]

In the solenoid valve of the present invention, the input signal current for on/off control of the solenoid is separated from the excitation power supply current of the solenoid coil, so the signal line connected to the solenoid valve for transmitting the input signal current The noise generated when the solenoid is turned on and off does not affect the noise, and it is possible to prevent the noise from being emitted from the power supply line to the outside as much as possible. Since it is only necessary to send a current contact signal, there is very little noise or EMI imparted to other equipment via the signal line, and in practical terms the performance is not much different from that using optical fiber signal lines. That's what you get.

In addition, the solenoid valve of the present invention displays the presence or absence of an input signal current, so when controlling the switching element in series with the solenoid coil on/off using the signal current, it is possible to check whether the signal current is being reliably applied. In addition to this, it also displays the presence or absence of back electromotive force when the solenoid coil is turned off, so you can check whether the solenoid coil is healthy or not, and whether the return operation when the valve body is turned off is performed correctly. can be determined.

In other words, in a DC solenoid valve that moves the valve body against the flow force and spring force by energizing the solenoid coil, when the energization is cut off by the switching element's cutoff operation, a reverse voltage several tens of times higher than the steady voltage will be generated. An electromotive force is induced at both ends of the solenoid coil, and to prevent this, a surge absorbing element such as a diode, capacitor, or other nonlinear resistance element is connected in parallel to the solenoid coil, and the counter electromotive force is returned to the coil as a surge current. I try to let them do it. In other words, this back electromotive force is caused by the action of the coil that tries to prevent its decrease when the current flowing to the coil is cut off, and the inductance value of the coil that changes moment by moment due to the movement of the spool and therefore the movable core, which returns to the neutral position due to the spring force. This is an abnormal voltage that occurs due to changes in the voltage, and the fact that this occurs means that the coil is healthy and the valve's OFF return operation is being performed correctly.

The present invention provides an operation display that combines the presence or absence of an input signal current and the presence or absence of this back electromotive force. It removes defects. In this case, it goes without saying that if both are displayed in different colors, it will be easier to visually recognize them.

Furthermore, according to the present invention, it is possible to provide an additional effect such that in a dual solenoid type electromagnetic valve, it is possible to confirm which flow direction the right or left solenoid is for by color-coded display.

According to the present invention, there is no need to use a lamp in parallel with the solenoid coil, and therefore the current flowing through the switching element in series with the coil can be reduced accordingly, which can alleviate the thermal conditions of the switching element. can also contribute.

Preferred embodiments of the present invention will be described below with reference to the drawings.

〔Example〕

FIG. 1 shows a DC solenoid excitation control circuit for a solenoid valve according to an embodiment of the present invention, which includes a valve body of the solenoid valve, a valve body moving inside the solenoid valve body, a solenoid plunger device for driving the valve body, etc. Mechanical parts are not shown.

In FIG. 1, 10 is a terminal box attached to the valve body, which includes a pair of power terminals 15, 16,
Solenoid coil 1 of solenoid plunger device
9 and a signal current input terminal 4. Power terminal 1
A DC solenoid excitation power supply 20 is connected to 5 and 16 by a power line, and the plug terminal 1
A solenoid coil 19 is connected to 7 and 18,
Further, the terminal 4 is connected to the power supply terminal 16 from the signal line 1 through the control switch 2 and the signal line 3.

In the terminal box 10, a series circuit of a solenoid coil 19 and a power switching transistor 12 as a switching element is connected between the power supply terminals 15 and 16 via the plug terminals 17 and 18. A resistor 11, a constant voltage diode 9, and a smoothing capacitor 8 connected between the power supply terminals 15 and 16 serve as an internally stabilized power supply for converting the non-smooth DC output of the DC solenoid excitation power supply, which generates a pulsating output, into a stabilized DC output. It constitutes a circuit, and its output supplies power to the photocoupler device 6. The photocoupler device 6 has GaAs on the input side.
An infrared light emitting diode 6-1 is used, and the output side includes a photodiode 6-2, a signal processing circuit (amplification circuit 6-3, Schmitt trigger 6-5, output transistor 6-6), and a constant voltage circuit 6-4. The power switching transistor 12 is of a digital output type using a light receiving element integrated into one chip, and the power switching transistor 12 is turned on and off by the collector output of the output transistor 6-6. On the input side of the photocoupler device 6, a constant voltage diode 5 as a current limiting element and a light emitting diode 13-1 for signal current display are connected in the forward direction between the power supply terminal 15 and the anode side of the light emitting diode. It is a series circuit, and the cathode side of the light emitting diode 6-1 is connected to the signal current input terminal 4. This constant current diode 5 is a light emitting diode 6- on the input side of the photocoupler device 6.
1, even if the voltage of the power supply terminal 15 as a signal power source is different, within a certain range, for example, 10 to 20 m.
This is to allow current A to flow, and if the voltage level of the power supply prepared by the user of the solenoid valve is known, a fixed resistor with a resistance value corresponding to that value can be used as a current limiting element. may be used instead. If not, specify the upper and lower limits of the signal power supply voltage, such as 5 to 100 V, and obtain a constant current of 10 to 20 mA at a voltage value within that range. By using a constant current diode that is selected so that it The result is a product that does not require adjustment or replacement.

There are two types of photocoupler devices 6, one in which the output becomes high level and the other in which the output becomes low level when a signal current is flowing through the input side, depending on the internal Schmitt trigger 6-5. As for solenoid valves, the solenoid is energized when input signal current is applied, and conversely, the solenoid is energized when there is no input signal current and is deenergized when input signal current is applied. It is possible to construct two types of things.

In the configuration shown in FIG. 1, the Schmitt trigger 6-
5, the output becomes high level only when current is flowing to the input side, and when switch 2 is off, no current flows to the light emitting diode 6-1 on the input side of photocoupler 6, and point A becomes low level. Power switching transistor 12
remains off. When the switch 2 is turned on, a signal current limited to a constant value by the constant current diode 5 flows through the light emitting diode 6-1 on the input side of the photocoupler 6, the power switching transistor 12 becomes conductive, and the solenoid coil 19 is excited. be done. In this excited state, that is, while a signal current is flowing through the input side light emitting diode 6-1 as described above, the display light emitting diode 13-1 lights up in red, for example.

In this embodiment, another display light emitting diode 13-2 is provided. That is, this display light emitting diode 13 - 2 forms a series circuit from one plug terminal 18 of the solenoid coil 19 to the other terminal 17 via the surge absorbing element 14 and the diode 21 . This series circuit forms a closed loop. And this display light emitting diode 1
The polarities of 3-2 and diode 21 are opposite to the excitation voltage applied across the solenoid coil. In this embodiment, the display light emitting diodes 13-1 and 13-2 constitute an integrated two-color light emitting diode 13 having a common cathode, but each may use a separate light emitting diode element. . In addition, a display light emitting diode 13
-1 emits red light as described above, whereas the other display light emitting diode 13-2 is selected to emit green light.

In FIG. 1, the power supply terminal 15 is used as a signal power supply.
Power is supplied to the constant current diode 5 from the point B, which may be supplied from the connection point B between the resistor 11 and the resistor 7, or alternatively, instead of the constant current diode 5, power is supplied from point B through another resistor. Even if you try to
Furthermore, power may be supplied from another independent signal power source. However, in this case, it is preferable that the cathode of the diode 21 be directly connected to the solenoid plug terminal 17.

Now, another display light emitting diode 13-
2 is turned on by the back electromotive force generated from the solenoid coil 19 when the excitation of the solenoid coil 19 is cut off. That is, while the signal current is present, the one display light emitting diode 13-1 emits, for example, red light, and when the signal current is cut off and the power switching transistor 12 is cut off, the solenoid coil 19 generates a back electromotive force. A surge current flows from the other display light emitting diode 13-2 through the diode 21 through the surge absorbing element 14 and into the closed loop between both ends of the solenoid coil 19, and the display light emitting diode 13-2 receives this surge current at a predetermined level. Only until the value falls below the value, a confirmation of the spool return operation at the time of off is displayed in green, for example. In this way, the display light emitting diodes 13-1 and 13-2 preferably display on/off operations using different colors.

In other words, each time the valve is switched ON/OFF, a red signal current is displayed and a green operation confirmation display is displayed for a short period of time immediately after the signal goes out.If both such red and green displays are displayed. The signal current is normally applied and solenoid coil 1
If the connection between 9 and terminals 17 and 18 is sound, coil 19
There was no wire breakage or burnout in the coil, confirming that the electrical system was completely sound. This is because, in general, in solenoid valves, the power terminals 15 and 16 are screw terminals and are less prone to connection failures, but the terminals 17 and
18 is often a plug-in terminal using a connector pin jack of the receptacle, so terminal 1
This is an advantage in that it can be confirmed considering that connection failures at points 7 and 18 are relatively likely to occur. If it is determined from the operation of the hydraulic system that the valve body of the solenoid valve still does not return in the above manner, it is assumed that the hydraulic system of this solenoid valve has a malfunction, such as a stuck spool.

Furthermore, as is clear from FIG. 1, the load on the power switching transistor 12 in the excited state is only the solenoid coil 19, and there is no load such as an extra indicator lamp, so the heat generation of the transistor 12 is suppressed to that extent. This makes it even more advantageous to use a heat sink for the electrical equipment in a narrow space.

FIG. 2 shows an example of both solenoid coils, and the parts belonging to one solenoid coil 19a are given a suffix a to the reference numeral of each part, and the parts belonging to one solenoid coil 19a are
Items belonging to b are given the subscript b. The signal source switches 2a and 2b may be non-contact switches such as transistors, and it is also possible to use the output of a normal sequencer. Here, the display light emitting diodes 13a-1 and 13-2 are designed to emit red light, and the display light emitting diodes 13a-2 and 13b-1 are designed to emit green light. In addition, 60 in Figure 2
a and 60b are photocoupler devices.

Hydraulic DC solenoid valves generally have a pressure port P, cylinder ports A and B, and a tank port T arranged in the valve body, and depending on which symmetrical solenoid device is energized (P → A → cylinder →B→T) or (P→B→cylinder→A→T), which are different oil flow directions. In order to be able to identify these two oil flow directions in correspondence with the solenoid device on the excitation side when the valve is installed, conventionally it has been indicated by embossed letters on the valve body, or by marking the left and right directions on the nameplate of the valve body. The symbol [A] or [B] corresponding to the solenoid device is displayed, and furthermore, the character symbol [A] or [B] is integrally molded or marked on the solenoid device itself.

However, if the solenoid valve is later painted, these letters and symbols may become indistinct, or if they are marked on a nameplate, this nameplate is often attached to a lid that waterproofly closes the electrical recess in the valve body. Therefore, if the cover is removed and installed in the opposite direction, the time may be completely reversed, and if the name plate comes off or becomes dirty, the time becomes unclear.Furthermore, if a symbol is attached to the solenoid device itself, the time may be completely reversed. There is a drawback that it is necessary to decide in advance which side the solenoid device should be attached to, the left or the right, and then prepare two types of solenoid devices.

Normally, when the above time symbol is excited, P→
A solenoid device that makes flow A is [A] solenoid A solenoid device that makes flow P → B is called [B] solenoid device, and each is marked with the symbol [A] or [B] and lights up when energized. The operation indicator light of the solenoid device and the above symbol are associated with each other, so that the direction of oil flow can be determined from the combination of these symbols. However, even when such an indicator light is lit, conventionally the same color is produced for [A] and [B], so for example, the marking symbol may be painted or dirty, or may be in the shadow of other parts, or even the name plate may be If it was removed or could not be seen, there was a risk that it would be impossible to determine the oil flow at all.

In the embodiment shown in FIG. 2, the signal current energization display for the coil 19a of the solenoid device [A] is performed in red, the confirmation display for the valve return operation when it is off is performed in green, and [B] the coil 1 of the solenoid device
As for 9b, this is done in green and red, and the coloring of the operation display in the solenoid devices [A] and [B] is reversed, thereby eliminating the above-mentioned discrimination error.

In each of the above embodiments, the surge absorbing element 14
Display light emitting diode 13-2 (or 13a-
2, 13b-2), but this shows an example in which the surge absorbing element is inserted in series with the coil 19, (19
a, 19b) are connected in series and parallel to display light emitting diodes 13-2, (13a-2, 13b-2).
Alternatively, the surge absorbing element 14 inserted in series may be omitted and the terminals 18, (18a, 18b) may be replaced by display light emitting diodes 13-2, (13a-2, 13b-2)
It may be directly connected to the anode. In addition, display light emitting diodes 13-1, (13a-1, 13b-1)
The connection points are not limited to the illustrated positions, but are connected to the current signal input terminals 4, (4a, 4) from the constant current diode 5 through the light emitting diode 6-1 on the photo coupler input side.
It may be inserted anywhere in the series circuit path leading to b).

〔Effect of the invention〕

As described above, according to the present invention, the excitation power supply terminal of the solenoid coil and the signal line can be separated, so that noise when the solenoid is turned on and off is less likely to be transmitted to the signal line, and the excitation power supply line and the signal line are separated. This makes it possible to lay out the signal lines so that noise from the power supply lines does not escape easily, and also reduces the risk of EMI being transmitted from the signal lines to other peripheral devices. Since it is also possible to only allow the current to flow, there is less noise generated in this respect as well.

Normally, when manufacturing hydraulic equipment, the electrical equipment that operates the solenoid valves, including the power supply for the solenoid valve solenoid, is generally manufactured by the electrical manufacturer using the same or shared power supply for other electronic equipment. However, when using the solenoid valve of the present invention, the power source for excitation of the solenoid valve solenoid can be separated from the power source of other electronic and electrical devices, so the solenoid valve manufacturer or hydraulic equipment manufacturer can independently manufacture this. In this case, a dedicated power supply for the solenoid valve solenoid does not require a constant voltage or constant current power supply, so it can be manufactured at a low cost.

The solenoid valve of the present invention requires an input signal power source in addition to the excitation power source, but the output current is 10 (mA).
Since a power supply for LED of about ~20 (mA) is sufficient,
It has the advantage of being able to be used in common with power supplies for other electronic devices, and noise from turning on and off the solenoid is less likely to be transmitted to this signal system.

Furthermore, the solenoid valve of the present invention can be operated by applying a small current switching signal of 10 to 20 (mA) to a signal line separated from the excitation power supply line, so it can be operated directly as an output unit of a normal sequencer for light loads. Regardless of whether it is a DC solenoid valve or an AC solenoid valve, it can be operated with one type of sequencer output unit.In particular, internal signal power type models can be directly driven by the sequencer output without using an output unit. is also possible.

Furthermore, according to the present invention, it is possible to confirm the energization and operation of the solenoid coil without connecting a display load in parallel with the solenoid coil, and to check whether or not a signal current flows through the signal line and as a result of the energization of the solenoid coil. In addition to being able to accurately display the energization operation, including whether the valve has returned to its original state when the valve is off, it is also possible to indicate whether the valve is energized or not, as well as whether the valve is energized or not ([A] or [B]). Confirmation of the flow direction can also be included in the function of the display operation.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing a solenoid excitation control circuit for a DC solenoid valve according to an embodiment of the present invention, and FIG. 2 is a circuit diagram showing an embodiment of the dual solenoid type. 4, 4a, 4b: Current signal input terminal, 5: Constant current diode (current limiting element), 6, 60a, 6
0b: Photocoupler device, 12: Power switching transistor (switching element), 13-
1, 13a-1: first display light emitting diode,
13-2, 13a-2: second display light-emitting diode, 13b-1: third display light-emitting diode, 13b-2: fourth display light-emitting diode,
14, 14a, 14b: surge absorption element, 15,
16: Power terminal, 19: Solenoid coil, 2
0: Excitation power supply.

Claims (1)

[Claims] 1. A series circuit of a solenoid coil and a switching element connected between a pair of excitation power supply terminals;
a control circuit that controls switching according to the on/off state of another input signal current separated from the current flowing through the solenoid coil; and a first display that lights up according to the input signal current to the control circuit. a second display light emitting diode that forms a closed loop with the solenoid coil and lights up by a back electromotive force generated from the solenoid coil when the switching element is cut off, and the control circuit A photocoupler device includes a light-emitting diode element that generates a light output based on an input signal current, and a light-receiving element that generates an electric output in response to the light output; a constant current diode to set a current value within a predetermined range, the light emitting diode element on the input side of the photocoupler device generates an on/off contact signal, a switch means, the constant current diode, and the first display; The current signal is connected to a DC signal power source through the light emitting diodes for use in series, respectively, and the switching element is made conductive or cut off by a switching signal based on the electrical output of the photocoupler device. Operation solenoid valve. 2. The electromagnetic valve according to claim 1, wherein the first display light emitting diode and the second display light emitting diode have different colors. 3 The first display light emitting diode and the second display light emitting diode have two first and second anode electrodes and one common cathode electrode, and a current flows from the first anode electrode to the common cathode electrode. The electromagnetic valve according to claim 1, characterized in that a light emitting diode is used that emits light in different colors when current flows and when current flows from the second anode electrode to the common cathode electrode. 4 A first series circuit of a first solenoid coil and a first switching element connected between the output terminals of the excitation power source, and separating the first switching element from the current flowing through the first solenoid coil. a first control circuit that performs switching control according to on/off of another first input signal current;
a first display light emitting diode that is lit by the first input signal current to the first control circuit;
a second display light emitting diode that forms a closed loop with the first solenoid coil and is lit by a back electromotive force generated from the first solenoid coil when the first switching element is cut off; a second series circuit of a second solenoid coil and a second switching element connected between output terminals; and a second series circuit in which the second switching element is separated from the current flowing through the second solenoid coil. a second control circuit that performs switching control according to on/off of the input signal current;
a third display light emitting diode that is lit by the second input signal current to the second control circuit;
a fourth display light emitting diode that forms a closed loop with the second solenoid coil and lights up by a back electromotive force generated from the second solenoid coil when the second switching element is cut off; A current signal operated solenoid valve characterized in that the first and third display light emitting diodes have different colors, and the second and fourth display light emitting diodes have different colors. 5. Claim 4, characterized in that the first and fourth display light emitting diodes are of the same color, and the second and third display light emitting diodes are of the same color. Solenoid valve described in . 6 The first display light emitting diode and the second display light emitting diode have two anode electrodes, first and second, and one common cathode electrode, and a current flows from the first anode electrode to the common cathode electrode. 5. The electromagnetic valve according to claim 4, characterized in that a light emitting diode is used that emits light in different colors when current flows and when current flows from the second anode electrode to the common cathode electrode. 7 The third display light emitting diode and the fourth display light emitting diode have two anode electrodes, first and second, and one common cathode electrode, and a current flows from the first anode electrode to the common cathode electrode. 5. The electromagnetic valve according to claim 4, characterized in that a light emitting diode is used that emits light in different colors when current flows and when current flows from the second anode electrode to the common cathode electrode. 8 The first and second control circuits each include a photocoupler device, the input side of each photocoupler device being connected to a DC signal power source via first and second switching means for producing an on/off contact signal, 5. The electromagnetic valve according to claim 4, wherein the corresponding switching elements are respectively made conductive and cut off by a switching output signal of the device.