JP3167876B2 - Solenoid operating state detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solenoid operating state detecting device for detecting the operating state of a solenoid such as a latching solenoid used for operating, for example, an on-off valve or a switching valve and maintaining the state. .

[0002]

2. Description of the Related Art Generally, when a shut-off valve such as an on-off valve or a switching valve is operated, a solenoid driving circuit drives a latching solenoid by passing a driving current to the latching solenoid in response to an on-off control signal or a switching control signal. The shut-off valve is operated by driving the latching solenoid. In such a case, even if the control signal is input, the shut-off valve may not operate. Therefore, it is necessary to confirm whether the shut-off valve has been operated reliably after the input of the control signal.

Conventionally, in order to confirm the operation of this valve,
The reed switch is installed in the leakage magnetic flux generated by the latching solenoid, and the operating state of the latching solenoid is indicated by controlling the reed switch on / off using the fact that the leakage magnetic flux is different depending on the operation state of the latching solenoid. There has been an operating state detecting device for a solenoid that generates an answer back signal.

However, in the above-described conventional operating state detecting device for a solenoid, since the reed switch is turned on and off according to the magnitude of the leakage magnetic flux to generate an answer back signal, the magnetic flux contacted by the contact piece of the reed switch is generated. If the level varies, the operating state of the solenoid cannot be reliably answered, and it is necessary to finely adjust the installation position of the reed switch. In particular, in the case of a solenoid for improving the efficiency, that is, the performance, the leakage magnetic flux is extremely reduced, so that the inaccuracy of the on / off operation of the reed switch described above becomes more remarkable.
Further, since the reed switch has a mechanical contact piece, there is a problem that reliability is inferior, such as a high possibility of failure due to wear of the contact piece.

Therefore, a solenoid operation state detecting device which reliably detects the operation state of the solenoid without troublesome adjustment and improves reliability has been proposed.
For example, JP-A-3-9272 and JP-A-4-28
No. 209 gazette. FIG.
FIG. 1 is a block diagram illustrating a configuration of a solenoid operation state detection device disclosed in Japanese Patent Application No. 9272. 8, a valve driving circuit 2 is connected to both ends of the coil L of the latching solenoid 1, and a driving current is supplied from the valve driving circuit 2 to the coil L. A detection resistor R is connected to the coil L in series. A sine wave oscillator 3 that outputs a sine wave signal is connected to both ends of the series-connected coil L and detection resistor R via analog switches SW1 and SW2.

The analog switches SW1 and SW2 are turned on and off in response to an answer strobe signal supplied from a CPU 5 described later, and the sine wave oscillator 3 controls the start and stop of the sine wave signal by the signal. Also,
The phase difference detection circuit 4 compares the phases of the coil L and the detection resistor R to determine whether the phase difference is equal to or more than a predetermined amount,
An answer back signal corresponding to the determination result is output to the CPU 5. The CPU 5 supplies a valve opening control signal and a valve closing control signal to the valve drive circuit 2, determines a valve opening and a valve closing state based on the answer back signal, and according to a result of the determination, determines the answer back strobe signal described above. Is output.

In the above-described conventional operating state detecting device for a solenoid, in the case of the valve opening control, the valve driving circuit 2 applies a valve opening drive current to the coil L in the direction of c → d, while the valve opening control is performed. In this case, the coil L
, A valve closing drive current flows in the direction d → c. Next, in any of the controls, an answer back strobe signal is output from the CPU 5, the analog switches SW1 and SW2 are turned on, a sine wave signal is output from the sine wave oscillator 3, and the sine wave signal is L and the detection resistor R. The sine wave current flowing through the coil L and the detection resistor R is detected by the phase difference detection circuit 4, and it is determined whether or not the phase difference between the two is greater than or equal to a predetermined amount.

The sine wave current flowing through the coil L has a phase delay with respect to the sine wave current flowing through the detection resistor R, and the phase delay in the valve open state is larger than the phase delay in the valve closed state. This is because the magnetic coupling between the movable piece and the coil L in the valve closed state is larger than the magnetic coupling in the valve open state. In other words, the inductance of the coil L of the latching solenoid is This is because it becomes larger than the inductance in the valve open state.
Therefore, the phase difference detection circuit 4 determines the above-described difference in the phase delay, and outputs a different answerback signal according to the difference in the phase difference. Then, the CPU 5 determines whether the valve is open or closed based on the answerback signal. Thus, Japanese Patent Application Laid-Open No. Hei 3-92
In the solenoid operating state detecting device disclosed in Japanese Patent Application Publication No. 72, a sine wave signal is applied to the solenoid, and the open / closed state of the valve is detected based on the magnitude of the phase difference between the voltage and the current.

Next, a description will be given of a solenoid operating state detecting device disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 4-28209. FIG. 9 is a block diagram showing a configuration of a solenoid operating state detecting device disclosed in Japanese Patent Laid-Open No. 4-28209. 9, a valve drive circuit 2 is connected to both ends of a coil L of a latching solenoid 1, and a drive current is supplied from the valve drive circuit 2 to the coil L. The coil L has a resistor R1 and transistors Q1 and Q2.
Are connected in series to the power supply Vcc, and the transistor Q2
, A capacitor C1 is connected in parallel between the collector and the emitter.

[0010] The voltage across the coil L is equal to the diode D1.
, D2, and the output voltage is supplied to a comparator 11. The comparator 11 compares the reference voltage divided by the resistor R2 and the semi-fixed resistor R3 with the output voltage of the amplifier 10, and when the output voltage is higher than the reference voltage, sets the "H" level. L level.

The CPU 5 outputs a valve opening control signal or a valve closing control signal to the valve driving circuit 2 according to an external signal, and outputs a detection request signal to the bases of the transistors Q 1 and Q 2 and the delay circuit 12. . After delaying the detection request signal by a predetermined time, the delay circuit 12 supplies the signal to a D input of a latch circuit 13 composed of a D flip-flop. The output of the comparator 11 is supplied to the CK (clock) input of the latch circuit 13, and the output of the latch circuit 13 is supplied to the CPU 5 as an answerback signal.

In the above-described conventional operating state detecting device for a solenoid, when the valve is changed from the valve open state to the valve closed state, the valve drive circuit 2 applies a valve closing drive current to the coil L in the direction c → d to the valve. Is closed, the CPU 5 outputs a detection request signal to turn on the transistors Q1 and Q2. As a result, a detection voltage is applied to the coil L from the power supply Vcc, and the voltage at both ends of the coil L is supplied to the comparator 11 via the amplifier 10.

On the other hand, when the valve is changed from the valve closed state to the valve open state, a valve drive circuit 2 applies a valve open drive current to the coil L in the direction d → c to open the valve. A signal is output to turn on the transistors Q1 and Q2. As a result, a detection voltage is applied to the coil L from the power supply Vcc, and the voltage at both ends of the coil L is supplied to the comparator 11 via the amplifier 10.

At this time, the output voltage of the amplifier 10 falls at a speed corresponding to the time constant of the inductance of the coil L and the resistance R1. As described above, the inductance of the coil L differs between the case where the valve is in the valve closed state and the case where the coil L is in the valve open state. That is, the inductance in the valve closed state is larger than the inductance in the valve open state. Accordingly, the time constant between the inductance of the coil L and the resistance R1 in the valve closed state is larger than the time constant in the valve open state.

As a result, the Q output (answer back signal) of the latch circuit 13 becomes "H" level when the valve is closed, and becomes "L" level when the valve is open. And
The CPU 5 determines whether the valve is open or closed based on the answerback signal. As described above, in the operating state detecting device for the solenoid disclosed in Japanese Patent Application Laid-Open No. 4-28209, the open / closed state of the valve is detected using the time constant of the resistance R1 and the coil L of the shutoff valve.

[0016]

By the way, in the solenoid operating state detecting device disclosed in Japanese Patent Laid-Open Publication No. Hei 3-92772, a sine wave signal is applied to the solenoid, and the valve is determined by the magnitude of the phase difference between voltage and current. In order to detect the open / closed state of the solenoid, there is a problem that the time required for detecting the operating state of the solenoid becomes longer and the circuit configuration becomes complicated.

In the solenoid operating state detecting device disclosed in Japanese Patent Laid-Open No. 4-28209, the open / closed state of the valve is detected by utilizing the time constant of the resistor R1 and the coil L of the shut-off valve. Since the time difference is several milliseconds, a clock having a high frequency is required to determine the time difference, and there is a problem that power consumption is increased and resolution for fluctuation of the coil L is small.

The present invention has been made in view of the above-mentioned circumstances, and has as its object to provide a solenoid operating state detecting device which has a simple configuration, can reduce power consumption, and can achieve high resolution in detection accuracy. .

[0019]

According to a first aspect of the present invention, there is provided a solenoid operating state detecting device for detecting an operating state of a movable piece of a solenoid, wherein the movable piece has an axial center. An oscillator constituted by a coil inserted into the coil, an oscillator for generating a pulse signal corresponding to the inductance of the coil, and discrimination for judging an operation state of the movable piece of the solenoid based on the pulse signal generated by the oscillator. Means.

According to the second aspect of the present invention, the first aspect of the present invention is provided.
The operating state detecting device for a solenoid according to claim 1, further comprising a counting unit that counts the number of pulses of the pulse signal generated by the oscillating unit for a certain period of time, wherein the determining unit determines whether or not the count by the counting unit exceeds a predetermined value. The operating state of the movable piece of the solenoid is thereby determined.

According to the third aspect of the present invention, the first aspect of the present invention is provided.
In the operating state detecting device for a solenoid according to the aspect, the solenoid includes a movable piece that closes a valve hole when the coil is excited, and a magnetic coupling between the movable piece and the coil is in a valve closed state. It is characterized by becoming larger and smaller when the valve is open.

According to the fourth aspect of the present invention, the first aspect is provided.
In the operating state detecting device for a solenoid according to the aspect, the solenoid includes a movable piece that opens a valve hole when the coil is excited, and a magnetic coupling between the movable piece and the coil is in a valve closed state. It is characterized in that it becomes smaller and becomes larger when the valve is open.

According to the fifth aspect of the present invention, there is provided the second aspect.
The apparatus for detecting an operating state of a solenoid according to claim 1, further comprising a time generating means for generating the predetermined time in the counting by the counting means.

According to the sixth aspect of the present invention, there is provided the second aspect.
In the operating state detecting device for a solenoid described in the above, the counting means counts the pulse signal for a certain period of time, and sends out one pulse when the counted number exceeds a predetermined value, and the discriminating means detects the pulse. Thus, the operation state of the solenoid is determined.

According to the seventh aspect of the present invention, in the second aspect,
The operating state detecting device for a solenoid according to the above, further comprising a holding unit that holds a state of the pulse output from the counting unit after the predetermined time.

According to the eighth aspect of the present invention, in the sixth aspect,
The operating state detecting device for a solenoid according to the present invention is characterized in that a switching means for selectively switching whether to invert one pulse output by the counting means is provided.

According to the ninth aspect of the present invention, there is provided the eighth aspect of the present invention.
In the operating state detecting device for a solenoid described in the above, the switching means is provided with a switch for obtaining a selection signal which is set to a high level when applied to one side and is set to a low level when applied to the other side, and one pulse output by the counting means at one end. And an exclusive-NOR circuit to which the other end is supplied with the selection signal.

[0028]

According to the present invention, a pulse signal corresponding to the inductance of the coil of the solenoid is generated by the oscillating means, and the operating state of the movable piece of the solenoid is determined by the determining means based on the pulse signal. As described above, since detection is performed by digital processing, it can be easily configured by a logic circuit. In addition, since operation at a low frequency is also possible, power consumption can be reduced, and detection accuracy can be increased.

[0029] Further, there is provided a counting means for counting the number of pulses of the pulse signal generated by the oscillating means for a predetermined time, and the discriminating means determines whether or not the counting number by the counting means exceeds a predetermined value. May be determined.

A solenoid is provided which has a movable piece that closes the valve hole when the coil is excited, and the exciting coupling between the movable piece and the coil increases when the valve is closed and decreases when the valve is open. May be used. Also, a solenoid may be provided that has a movable piece that opens the valve hole when the coil is excited, and that the magnetic coupling between the movable piece and the coil decreases when the valve is closed and increases when the valve is open. Good.

Further, a time generating means for generating the predetermined time in the counting by the counting means may be provided. The counting means counts the pulse signal for a certain period of time, and sends out one pulse when the counted number exceeds a predetermined value. The discriminating means detects the pulse to change the operating state of the solenoid. The determination may be made.

[0032] Further, a holding means for holding the state of the pulse output from the counting means after the predetermined time may be provided. Further, switching means for selectively switching whether to invert one pulse output from the counting means may be provided.

Further, the switching means is provided with a switch for obtaining a selection signal which becomes high level when applied to one side and becomes low level when applied to the other side, and one pulse which is output by the counting means is supplied to one end and the other end is provided. And an exclusive-NOR circuit to which the above selection signal is supplied.

[0034]

Next, an embodiment of the present invention will be described with reference to the drawings.

1. Configuration of First Embodiment First, a shutoff valve used in the first embodiment will be described with reference to FIG. FIG. 3A is a sectional view of a shut-off valve (type A) used in the related art or the first embodiment. In FIG. 3A, the shut-off valve is
It is constituted by a latching solenoid 30, a valve element 31 operated by the latching solenoid 30, and a valve seat 32 having a valve hole 32a opened and closed by the valve element 31. The latching solenoid 30 includes a coil L, a movable piece (plunger) 30a, a magnet Mg, and a yoke 32. A spring SP1 is interposed between the valve element 31 and the yoke 32. The spring SP1 is normally in a contracted state shown on the left side of FIG. 3A, and when it is stretched, a force for returning the contracted state is applied.

In the configuration described above, when no driving current is applied to the coil L, the movable piece 30a
The valve is retracted by the contraction force of 1 and the valve hole 32a is opened (the left side in FIG. 3A). When a drive current is applied to the coil L in this valve open state, the movable piece 30
“a” extends the spring SP1, and the valve element 31 comes into contact with the valve seat 32 to be in a valve-closed state (right side in FIG. 3A). In this state, even when the energization of the coil L is stopped, the movable piece 30a maintains the valve-closed state because the magnet Mg, the frame of the latching solenoid 30, the yoke 32, and the plunger 30a form a magnetic closed circuit. . on the other hand,
When a relatively small current flows in the coil L in the opposite direction to the drive current in the valve closed state, the holding force of the magnetic closed circuit is reduced, and the movable piece 30a is pulled back by the contraction force of the spring SP1, and the valve hole 32a Is opened (left side in FIG. 3A).

In the type A shut-off valve, the movable piece 30a
The magnetic coupling between the coil and the coil L increases when the valve is closed and decreases when the valve is open. Therefore, the inductance of the coil L in the valve closed state is larger than the inductance in the valve open state. In the type A shut-off valve, the spring SP1 is stretched when the valve is opened, so that a larger current is required than when the valve is closed.

FIG. 1 is a block diagram showing the configuration of the first embodiment of the present invention. In the figure, a CPU (determination means) 20 supplies a detection request signal a for a predetermined period to a time generation circuit 21 at a predetermined timing, and a valve 20 based on an answer back signal e supplied from a latch circuit 24 described later. Determine the state. The detection request signal a
Is a signal instructing the start of the determination of the valve closed state. The time generating circuit (time generating means) 21 includes an external resistor R10, and when the detection request signal a is supplied, the clock b having the pulse width T determined by the external resistor R10 is supplied to the oscillator 22 and the counter 23. , And to the latch circuit 24.

The oscillator (oscillating means) 22 constitutes an LC oscillator by a coil L of a latching solenoid and a capacitor C connected in series with the coil L. During the period when the clock b is supplied, A clock c having a frequency determined by the coil L and the capacitor C is output. The counter (counting means) 23 counts the number of pulses of the clock c, and outputs a pulse signal d having a constant pulse width when the number of pulses exceeds a predetermined value. Next, the latch circuit (holding means) 24 is composed of a D flip-flop, and latches the state of the pulse signal d supplied to the D input by the clock b supplied to the CK (clock) input, and C as the back signal e
The data is supplied to the PU 20.

2. Next, the operation of the above-described first embodiment will be described with reference to the timing chart shown in FIG. First, it is assumed that the valve is in a closed state as an initial state. At time t0, when a valve opening instruction is externally requested to the CPU 20, the CPU 20 outputs a detection request signal a for a certain period at time t1 shown in FIG. The time generation circuit 21 receives the detection request signal a, generates a clock b having a pulse width T determined by the external resistor R10, and supplies the clock b to the oscillator 22, the counter 23, and the CK input of the latch circuit 24.

The oscillator 22 supplies a clock c having a frequency determined by the coil L and the capacitor C of the latch solenoid to the counter 23 during the period (pulse width) T during which the clock b is supplied. The clock c is counted by the counter 23 from the rising of the clock b. At this time, since the valve is in the open state, the inductance of the coil L is smaller than the inductance in the valve closed state, as described above. Therefore, the frequency of the clock c determined by the coil L and the capacitor C in the valve open state is higher than the frequency in the valve closed state described later. That is, in the valve open state, the clock c
Is shortened, and the number of pulses in the period T increases. Therefore, at time t2 when the count value of the counter 23 exceeds a predetermined value, the counter 23 supplies a pulse signal d having a constant pulse width to the D input of the latch circuit 24.

The latch circuit 24 determines the state of the pulse signal d,
That is, the state of "H" is held at the time t3 at the timing of the falling edge of the clock b. Thus, in the valve open state, the answerback signal e becomes “H”.

On the other hand, at time t4, the CPU
When a valve closing instruction is requested to the CPU 20, the CPU 20
Outputs a detection request signal a for a certain period at time t5 shown in FIG. The time generation circuit 21 outputs a detection request signal a
In response, a clock b having a pulse width T determined by the external resistor R10 is generated, and the clock b is supplied to the oscillator 22, the counter 23, and the CK input of the latch circuit 24.

The oscillator 22 supplies a clock c having a frequency determined by the coil L and the capacitor C of the latch solenoid to the counter 23 during a period (pulse width) T during which the clock b is supplied. The clock c is counted by the counter 23 from the rising of the clock b. At this time, since the valve is in the closed state, the coil L
Is larger than the inductance in the valve open state. Therefore, the frequency of the clock c determined by the coil L and the capacitor C in the valve closed state is lower than the frequency in the valve open state described above. That is, in the valve closed state, the cycle of the clock c becomes longer, and the number of pulses in the period T decreases. Therefore, the count value of the counter 23 does not exceed a predetermined value within the period T. As a result, the pulse signal d is not output from the counter 23, and the latch circuit 24 holds the state of the pulse signal d, that is, the state of "L" at the time t6 of the falling edge timing of the clock b. Thus, in the valve closed state, the answerback signal e becomes “L”.

After outputting the detection request signal a, the CPU 20 does not need to monitor or control the circuit operation. Therefore, the CPU 20 performs other processing during this time, and after a predetermined time, is latched by the latch circuit 24. The answerback signal e may be captured.

As described above, according to the first embodiment, unlike analog detection, detection is performed by digital processing, so that it can be easily configured by a logic circuit. In addition, since operation at a low frequency is also possible, power consumption can be reduced. 3. Configuration of Second Embodiment Next, a second embodiment of the present invention will be described. In the second embodiment, in addition to the operation of the first embodiment, a different type of shut-off valve can be used. FIG. 3B is a cross-sectional view of a shutoff valve (type B) different from the shutoff valve used in the first embodiment described above.

In FIG. 3B, the shut-off valve includes a latching solenoid 30, a valve element 31 operated by the latching solenoid 30, and a valve seat 32 having a valve hole 32a opened and closed by the valve element 31. It is configured.
The latching solenoid 30 includes a coil L, a movable piece (plunger) 30a, a magnet Mg, and a yoke 32. A spring SP2 is interposed between the valve element 31 and the yoke 32. The spring SP2 has an operation opposite to that of the above-described spring SP1, and is normally in an extended state shown on the right side of FIG. 3B, and when contracted, the force for returning to the extended state is reduced. It is working.

In the configuration described above, when no driving current is supplied to the coil L, the movable piece 30a
2 and the valve hole 32a is closed (the right side in FIG. 3B). When a DC valve opening current flows through the coil L in this valve closed state, the movable piece 30a is excited. When the direction of the valve-opening current is set so that the excited magnetic pole of the movable piece 30a is different from the magnetic pole of the magnet Mg, the movable piece 30a is attracted to the magnet Mg, whereby the valve body 31 is separated from the valve seat 32. The valve is in the open state (the left side in FIG. 3B). In this state, even if the energization of the coil L is stopped, the magnet Mg, the latching solenoid 3
Since the magnetic closed circuit is formed by the frame 0, the yoke 32, and the plunger 30a, the movable piece 30a keeps the valve open. On the other hand, when a relatively small current flows in the coil L in a direction opposite to the valve opening current in the valve open state, the holding force by the magnetic closed circuit decreases, and the movable piece 30a is pushed up by the extension tension of the spring SP2, Valve hole 32
a becomes the valve closed state (the right side in FIG. 3B).

As described above, in the type B shut-off valve shown in FIG. 3B, the magnetic coupling between the movable piece 30a and the coil L is small when the valve is closed and large when the valve is open. Therefore, the inductance of the coil L in the valve closed state is smaller than the inductance in the valve open state. In the type B shut-off valve, the spring SP2 is contracted when the valve is closed, so that a larger current is required than when the valve is opened.

As described above, the type B shut-off valve shown in FIG. 3B is different from the type A shut-off valve shown in FIG. 3A in the inductance of the coil L in the valve closed state and the valve open state. The relationship is reversed. In the second embodiment, FIG.
Whether the type A shutoff valve shown in FIG. 3A or the type B shutoff valve shown in FIG. 3B is used, the operation state can be determined.

FIG. 4 is a block diagram showing the construction of the solenoid operating state detecting apparatus according to the second embodiment. 4, the same reference numerals are given to the portions corresponding to FIG. 2 described above, and description thereof will be omitted. In the second embodiment, as shown in FIG. 4, a selection switch SW3 pulled up to a power supply VDD by a resistor R11 and an EXNOR
(Exclusive negative OR circuit) 40. When the above-mentioned type A shut-off valve is used, the selection switch (switching means) SW3 is turned on to the power supply VDD side, and the type B
When the shut-off valve is used, it is put on the ground side. A latch circuit 24 is provided at one end of the EXNOR 40.
The pulse e output from is supplied.
An "H" level or "L" level selection signal f is supplied via the selection switch SW3. EX
The NOR (switching means) 40 outputs the state (level) of the pulse e as an answer back signal g as it is when the selection signal f is "H", and changes the state of the pulse e when the selection signal f is "L". The signal is inverted and output as an answerback signal g.

4. Next, the operation of the above-described second embodiment will be described with reference to the timing charts shown in FIGS. FIG. 5 is a timing chart for explaining the operation when the type A shut-off valve is used, and FIG. 6 is a timing chart for explaining the operation when the type B shut-off valve is used.

First, the case where a type A shut-off valve is used will be described with reference to FIG. In this case, the selection switch SW3 is turned on to the power supply VDD, and EXNOR4
0 is supplied with an “H” level selection signal f. The operation from the time at which the valve opening instruction is externally requested to the CPU 20 at time t0 to the time t3 at which the pulse e is output from the latch circuit 24 is the same as that of the first embodiment.

That is, in this case, in the valve open state, the inductance of the coil L becomes smaller than the inductance in the valve closed state, and the coil L and the capacitor C
The frequency of the clock c determined by the above becomes higher than the frequency in the valve closed state described later. Therefore, in the valve open state, the cycle of the clock c is shortened, and the number of pulses in the period T is increased.
At time t2 when the count value of the counter 3 exceeds the predetermined value, the pulse signal d having a constant pulse width
Supply to input.

The latch circuit 24 determines the state of the pulse signal d,
That is, the state of "H" is held at the time t3 of the falling edge of the clock b, and the pulse e is set to E.
Supply to one end of XNOR40. In this case, EXNOR
The EXNOR 40 outputs the “H” level pulse e as it is as the answer back signal g because the other end of the 40 is supplied with the “H” level selection signal f.

On the other hand, at time t4, the CPU 2
When a valve closing instruction is requested for 0 and the valve is closed,
The inductance of the coil L is larger than the inductance in the valve open state. Therefore, the frequency of the clock c determined by the coil L and the capacitor C in the valve closed state is lower than the frequency in the valve open state described above. That is, in the valve closed state, the cycle of the clock c becomes longer and the number of pulses in the period T decreases, so that the count value of the counter 23 does not exceed the predetermined value in the period T.

As a result, the pulse signal d is not output from the counter 23, and the latch circuit 24 outputs the pulse signal d.
, That is, the state of "L" is held at the time t6 of the falling edge timing of the clock b, and EXNO
Supply to one end of R40. In this case, since the other end of the EXNOR 40 is supplied with the "H" level selection signal f, the EXNOR 40 outputs the "L" level pulse e as it is as the answer back signal g.

As described above, when the type A shut-off valve is used, the same detection result as in the first embodiment can be obtained by turning on the selection switch SW3 to the power supply VDD side. CP
After outputting the detection request signal a, the U20 does not need to monitor or control the circuit operation. During this time, the U20 performs other processing, and after a predetermined time, the answerback signal latched by the latch circuit 24. e should be taken in.

Next, a case where a type B shut-off valve is used will be described with reference to FIG. In this case, the selection switch SW3 is turned on to the ground side, and the EXNOR 40 is supplied with the “L” level selection signal f. In this case, in the valve open state, the inductance of the coil L becomes larger than the inductance in the valve closed state,
The frequency of the clock c determined by the coil L and the capacitor C is lower than the frequency in a valve closed state described later. Therefore, in the valve open state, the cycle of the clock c becomes longer, and the number of pulses in the period T becomes smaller.
The count value of the counter 23 does not exceed a predetermined value within the period T.

As a result, the pulse signal d is not output from the counter 23, and the latch circuit 24 outputs the pulse signal d.
, That is, the state of "L" is held at the time t2 of the falling edge timing of the clock b, and EXNOR
40 to one end. In this case, since the “L” level selection signal f is supplied to the other end of the EXNOR 40, the EXNOR 40 inverts the “L” level pulse e to generate the “H” level answerback signal g. Output.

On the other hand, at time t3, the CPU
When a valve closing instruction is requested to 20 and the valve is closed,
The inductance of the coil L is smaller than the inductance in the valve open state. Therefore, the frequency of the clock c determined by the coil L and the capacitor C in the valve closed state is higher than the frequency in the above-described valve open state. That is, in the valve closed state, the cycle of the clock c becomes short and the number of pulses in the period T increases, so that the counter 23 sets the pulse width of the fixed pulse width at time t5 when the count value of the counter 23 exceeds the predetermined value. Pulse signal d
To the D input of the latch circuit 24.

The latch circuit 24 determines the state of the pulse signal d,
That is, the state of "H" is held at the time t6 of the falling edge timing of the clock b and the pulse e is set to E.
Supply to one end of XNOR40. In this case, EXNOR
The EXNOR 40 inverts the “e” level pulse e and outputs it as an “e” answerback signal g because the “L” level selection signal “f” is supplied to the other end of the “E”.

As described above, when the type B shut-off valve is used, by turning on the selection switch SW3 to the ground side, the same detection result as in the case of type A or the first embodiment can be obtained. can get. After outputting the detection request signal a, the CPU 20 does not need to monitor or control the circuit operation. Therefore, the CPU 20 executes other processing during this time, and after a predetermined time, the answerback signal e latched by the latch circuit 24. I just need to take in.

As described above, according to the second embodiment,
In addition to the effects of the first embodiment, the operation state of the solenoid can be detected even if the type of the shutoff valve is different.

As shown in FIG. 7 (a), the shut-off valve of the type A in the first embodiment is normally in the extended state, and the spring SP3 which is contracted in the valve closed state is operated by a latching solenoid. 30 may be built in. In addition, type B in the second embodiment
The shut-off valve of FIG.
4 may be provided below the movable piece 30a.

Which shutoff valve to use may be determined according to the situation to which the shutoff valve is applied. That is, FIG.
In the shut-off valves shown in FIGS. 1A and 1B, a large current is required when the valve is closed or the valve is opened, regardless of the type. For this reason, when the shut-off valve is driven by a lithium battery or the like, there is a concern about the life of the battery. In such a case, the valve operation may be performed manually.
(B) or the shut-off valve shown in FIG. 7 (b) is used.

It is desirable that the valve can be closed with a small current in an emergency such as a gas leak.
In the shut-off valve shown in (a), in order to shift from the valve open state to the valve closed state, it is necessary to supply a current that overcomes the contraction force of the springs SP1 and SP3.
This is because, in the shut-off valve shown in FIG. 3B or FIG. 7B, the valve can be closed even with a small current due to the tension of the springs SP2 and SP4.

[0068]

As described above, according to the first aspect of the present invention, in the solenoid operating state detecting device for detecting the operating state of the movable piece of the solenoid, the coil in which the movable piece is inserted about the center of the shaft is provided. An oscillator configured to generate a pulse signal corresponding to the inductance of the coil, and a determination unit configured to determine an operation state of the movable piece of the solenoid based on the pulse signal generated by the oscillation unit. In this way, since the detection is performed by digital processing, it can be easily configured by a logic circuit.
Further, since operation at a low frequency is also possible, there is an advantage that power consumption can be suppressed and detection accuracy can be increased.

According to a second aspect of the present invention, there is provided a counting means for counting the number of pulses of the pulse signal generated by the oscillating means for a certain period of time, wherein the discriminating means determines that the counting number by the counting means is a predetermined value. The operation state of the movable piece of the solenoid is determined based on whether or not it exceeds the limit.Therefore, since the detection is performed by digital processing, it can be easily configured by a logic circuit. The advantage is that the power can be kept low and the detection accuracy can be made high.

According to the third aspect of the present invention, the solenoid includes a movable piece that closes a valve hole when the coil is excited, and a magnetic coupling between the movable piece and the coil. Is increased when the valve is closed, and decreased when the valve is open.Since the detection is performed by digital processing, it can be easily configured by a logic circuit.Also, operation at a low frequency is also possible, so that power consumption is reduced. This has the advantage that it is possible to suppress this and that the detection accuracy can be increased.

According to a fourth aspect of the present invention, the solenoid includes a movable piece that opens a valve hole when the coil is excited, and a magnetic coupling between the movable piece and the coil. Is reduced when the valve is closed, and increased when the valve is open.The detection is performed by digital processing, so it can be easily configured with a logic circuit.Also, operation at a low frequency is also possible, so that power consumption is low. This has the advantage that it is possible to suppress this and that the detection accuracy can be increased.

According to the fifth aspect of the present invention, since the time generating means for generating the predetermined time in the counting of the counting means is provided, the detection can be easily realized by a logic circuit since the detection is performed by digital processing. ,
Further, since operation at a low frequency is also possible, there is an advantage that power consumption can be suppressed and detection accuracy can be increased.

According to the invention described in claim 6, the counting means counts the pulse signal for a predetermined time, and sends one pulse when the count exceeds a predetermined value.
The determining means determines the operating state of the solenoid by detecting the pulse.Since the detection is performed by digital processing, it can be easily configured by a logic circuit, and can also operate at a low frequency. Therefore, there is an advantage that power consumption can be suppressed and detection accuracy can be increased.

According to the seventh aspect of the present invention, since the holding means for holding the state of the pulse output from the counting means after the predetermined time is provided, the detection by digital processing is performed by a logic circuit. Since it can be easily configured and can operate at a low frequency, power consumption can be suppressed and detection accuracy can be increased. Until the determination is made, another process is executed, and after a predetermined time, the result held by the holding unit may be fetched. Therefore, there is an advantage that the determination unit can be used efficiently.

According to the invention of claim 8, since the switching means for selectively switching whether or not to invert one pulse output by the counting means is provided, the detection is performed by digital processing. It can be easily configured with a logic circuit and can operate at a low frequency, so that power consumption can be kept low and the detection accuracy can be made high resolution. Even when using a solenoid that has
The advantage is obtained that the operating state of the solenoid can be determined according to the characteristics.

According to the ninth aspect of the present invention, the switching means is a switch for obtaining a selection signal which is set to a high level when applied to one side and is set to a low level when applied to the other side; And the other end is supplied with the exclusive-NOR circuit to which the selection signal is supplied. Since the detection is performed by digital processing, it can be easily configured by a logic circuit. In addition, since the power consumption can be reduced, the power consumption can be suppressed and the detection accuracy can be increased.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a first exemplary embodiment of the present invention.

FIG. 2 is a timing chart for explaining the operation of the first embodiment.

FIG. 3 is a sectional view showing a structure of a different shut-off valve;
(A) is a cross-sectional view of a shut-off valve (type A) used in the related art or the first embodiment, and (b) is a cross-sectional view of a different shut-off valve (type B).

FIG. 4 is a block diagram showing a configuration of a second exemplary embodiment of the present invention.

FIG. 5 is a timing chart for explaining the operation of the second embodiment when a type A shutoff valve is used.

FIG. 6 is a timing chart for explaining the operation of the second embodiment when a type B shut-off valve is used.

7A is a partial cross-sectional view showing another example of a type A shut-off valve, and FIG. 7B is a partial cross-sectional view showing another example of a type B shut-off valve.

FIG. 8 is a block diagram showing a configuration of a conventional operation state detecting device for a solenoid.

FIG. 9 is a block diagram showing a configuration of a conventional operating state detecting device for a solenoid.

[Explanation of symbols]

 Reference Signs List 20 CPU (determination means) 21 Time generation circuit (time generation means) 22 Oscillator (oscillation means) 23 Counter (counting means) 24 Latch circuit (holding means) 40 EXNOR (exclusive negative OR circuit, switching means) L coil SW3 Selection switch (switching means, switch)

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kazumitsu Natsui 9-10 Misonodai, Fujisawa-shi, Kanagawa (72) Inventor Hideo Kato 3-28-70-108 Minamisenju, Arakawa-ku, Tokyo (72) Inventor Shigenori Okamura 4-1-2, Hirano-cho, Chuo-ku, Osaka-shi, Osaka (72) Inventor Yukio Kimura 507-2 Shinhocho-cho, Tokai-shi, Aichi Toho Gas Co., Ltd. 23, Minamikashima, Futamata-cho, Tenryu-shi, Japan Yazaki Keiki Co., Ltd. (58) Field surveyed (Int.Cl. ⁷ , DB name) H01F 7/18

Claims (9)

(57) [Claims] 1. A solenoid operating state detecting device for detecting an operating state of a movable piece of a solenoid, wherein the movable piece forms an oscillator by a coil inserted around an axis, and generates a pulse signal according to the inductance of the coil. And a determining means for determining an operating state of the movable piece of the solenoid based on a pulse signal generated by the oscillating means. A counting means for counting a number of pulses of the pulse signal generated by the oscillating means for a predetermined time, wherein the determining means determines whether or not the count of the counting means exceeds a predetermined value. The operating state detecting device for a solenoid according to claim 1, wherein the operating state of the piece is determined. 3. The solenoid includes a movable piece that closes a valve hole when the coil is energized, and a magnetic coupling between the movable piece and the coil increases when the valve is closed, and the valve opens. 2. The device according to claim 1, wherein the value is smaller in a state.
An operating state detecting device for the solenoid as described in the above. 4. The solenoid includes a movable piece that opens a valve hole when the coil is energized, and a magnetic coupling between the movable piece and the coil decreases in a valve closed state, and the valve opens. 2. The method according to claim 1, wherein the size is increased in a state.
An operating state detecting device for the solenoid as described in the above. 5. The solenoid operating state detecting device according to claim 2, further comprising a time generating means for generating the predetermined time in the counting by the counting means. 6. The counting means counts the pulse signal for a certain period of time, and sends out one pulse when the counted number exceeds a predetermined value. The discriminating means detects the pulse to thereby produce the solenoid. 3. The operating state detecting device for a solenoid according to claim 2, wherein the operating state is determined. 7. The operating state detecting device for a solenoid according to claim 2, further comprising a holding means for holding a state of a pulse output from said counting means after said predetermined time. 8. The solenoid operating state detecting device according to claim 6, further comprising a switching means for selectively switching whether or not one pulse output from said counting means is inverted. 9. A switch for obtaining a selection signal which is set to a high level when applied to one side and is set to a low level when applied to the other side; one pulse supplied from the counting means is supplied to one end; 9. An apparatus according to claim 8, further comprising an exclusive-NOR circuit to which said selection signal is supplied.