JPH05280654A - Driving system of stepping motor for operating shutoff valve and safety gas meter - Google Patents

Abstract

PURPOSE:To elongate a battery life for a safety gas meter by effectively using electric energy of a battery for driving a stepping motor. CONSTITUTION:Terminal voltage of a battery 14 is detected by a battery voltage detecting part 5. The battery 4 is connected in parallel, when the terminal voltage is high, and in series, when the terminal voltage is low, in a battery connection switching part 6. A resistor is inserted to a power feed circuit, when the terminal voltage is high, and removed from the power feed circuit, when the terminal voltage is low, in a current limiting resistor inserting circuit 7. When the terminal voltage is high and when a large load is applied to a shutoff valve, a frequency is decreased by an output frequency switching part. When the shutoff valve is in a large load, a stepping motor is driven by 2-phase excitation by an excitation method switching part 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive system of a stepping motor for operating a shutoff valve and a safety gas meter using the same.

[0002]

2. Description of the Related Art In a safety type gas meter, a stepping motor is normally or reversely rotated to open and close a shutoff valve. Further, one or a plurality of batteries are used as a power source for driving the stepping motor.

When the shutoff valve is closed, gas supply is stopped and gas pressure is applied so as to press the valve body against the valve seat. Therefore, when opening the shut-off valve from this closed state, the so-called depressurization until the valve element is slightly separated from the valve seat increases the load for operating the valve element, and a large driving force is required for the stepping motor. At the time of so-called valve pulling up in which the body is further pulled away from the valve seat, even if the driving force of the stepping motor for operating the valve body is smaller than that at the time of depressurizing, it operates.

A battery for a power supply is used for 10 years, but if a battery left for a long time of 10 years is used, the internal resistance of the battery increases and the terminal voltage decreases. Further, there is a characteristic that the voltage drop of the battery becomes large in a low temperature environment, and the terminal voltage of the battery also drops.

[0005]

SUMMARY OF THE INVENTION In the above conventional technique,
The terminal voltage of the battery is applied to the exciting coil of the stepping motor from the terminal of the battery through the motor drive circuit,
Power was supplied to the exciting coil of the stepping motor 10 years later even when the voltage of the battery terminal dropped or even when the voltage of the battery terminal dropped in a low temperature environment.

For this reason, at the initial stage when a new battery is installed, or when the temperature is high, a larger amount of electric power than is necessary and sufficient for opening and closing the shutoff valve is supplied to the stepping motor,
There is a problem that the efficiency of use of the battery is poor and the life of the battery is shortened.

Therefore, the present invention solves this problem,
A first object of the present invention is to provide a drive system of a stepping motor for shutting off a valve, which can improve the efficiency of use of the battery and prolong the actual battery life.

Further, as described above, when the pressure is released at the initial stage of opening the shutoff valve, a larger load is applied to the stepping motor than when the valve is pulled up or closed, and a large amount of power is consumed accordingly. Also, when pulling up a valve that does not require a driving force or when closing the valve, it consumes as much power as when depressurizing, wasting battery power and thus shortening battery life. was there.

Therefore, it is a second object of the present invention to eliminate such a problem.

[0010]

In order to achieve the first object, the first invention is a drive system of a stepping motor for opening and closing a shutoff valve, which comprises a battery for power supply,
The battery voltage detection unit that measures the terminal voltage of this battery, and the following (a) to operate that operates according to the output of the battery voltage detection unit:
It is characterized in that at least two of the power feeding force control means of (C) are provided.

(A) A power feeding force control means comprising a current limiting resistor insertion circuit for connecting a current limiting resistor to the power feeding circuit when the terminal voltage of the battery is above a certain level and removing the current limiting resistor when the terminal voltage is below a certain level.

(B) When the terminal voltage of the battery is above a certain level, the frequency for driving the stepping motor is increased, and when it is below a certain level, the frequency for driving the stepping motor is decreased. .

(C) A power feeding force control means comprising an excitation system switching section which sets the excitation system for driving the stepping motor to one-phase excitation when the terminal voltage of the battery is above a certain level and to the two-phase excitation when it is below a certain level. ..

Further, in the second invention, instead of the power feeding force control means of the first invention, the following power feeding force control means of (a ′) is required. (A ′) A power feeding force control means comprising a resistor selection switching unit that prepares current limiting resistors having different resistance values and selects and uses the resistance value of the current limiting resistor according to the terminal voltage of the battery.

A third aspect of the invention is to use a plurality of power source batteries,
In addition to the power feeding force control means of the first or second invention, the following power feeding power control means (d) is added, and these power feeding force control means (a) (a ') to (d) are added. It is characterized by having at least two of them.

(D) A feeding power control means comprising a battery connection switching unit for connecting batteries in parallel when the terminal voltage of the battery is above a certain level and connecting them in series when the terminal voltage is below a certain level. In order to achieve the above first and second objects, the fourth invention adds the power feeding force control means of the first, second or third invention, and these power feeding force control means (a) ( A security type gas meter characterized by comprising at least one of (e) to (e) among (e) to (e) and one other than (e) and (e).

(E) A power feeding force control means comprising an output frequency switching section for decreasing the frequency for driving the stepping motor when releasing the valve pressure and increasing the driving frequency for raising the valve opening and closing the valve.

(F) A two-phase excitation system is used when depressurizing an opening valve that requires a large force to drive a shutoff valve, and a one-phase excitation system is used when opening and closing the valve. Power supply control means.

[0019]

The battery voltage detection unit detects the terminal voltage of the battery.
Each power feeding force control means controls the power feeding force to the step motor according to the terminal voltage detected by the battery voltage detection unit.

(A) The current limiting resistance insertion circuit controls the current to the step motor when the terminal voltage of the battery is equal to or higher than a certain level. (B) When the terminal voltage of the battery is equal to or higher than a certain level, the output frequency switching unit raises the frequency to open or close the shutoff valve in a short period of time to save the power consumed for shutoff valve operation. Further, when the battery voltage becomes low, the frequency is reduced so that the step motor can respond even when the voltage is low, and the battery can be used up to the end.

(C) When the terminal voltage of the battery is above a certain level, the excitation method switching section performs one-phase excitation to reduce power consumption,
When the voltage is below a certain level, 2-phase excitation is used and the battery is used up to the low voltage.

(A ') The resistor selection switching unit finely switches the current limiting resistance to an appropriate value according to the terminal voltage of the battery to reduce unnecessary power consumption when the battery voltage is high.

(D) When the battery is new and the terminal voltage is above a certain level, the battery connection switching unit is connected in parallel, and when the battery is old and the terminal voltage is below a certain level, it is switched to the series connection to reduce the amount of battery power. Extend the battery life by fully utilizing it to the end.

(E) The output frequency switching unit switches the drive frequency according to the load applied to the stepping motor when the shutoff valve is opened, and when the pressure is released when the valve is heavily loaded, the frequency is decreased to increase the drive force. Since the load is small when the valve is opened and closed, the frequency is increased to complete the operation in a short time and save power.

(F) The excitation method switching section adopts a two-phase excitation method when depressurizing the valve, which requires a large force to drive the shutoff valve, and requires a force when opening the valve and when closing the valve. Since it does not, switch to the one-phase excitation method to save power.

[0026]

1 is a first embodiment of the present invention, FIG. 2 is a second embodiment, and the second embodiment is only partially different from the first embodiment. .

A shutoff valve 1 opens and closes the gas flow path of the gas meter 2. A stepping motor 3 is mechanically connected to the shutoff valve 1, and the shutoff valve opens or closes when the stepping motor 3 rotates normally or reversely.

4 is an even number of batteries. Reference numeral 5 is a battery voltage detection unit that detects the terminal voltage of the battery 4, and 6 is a battery connection switching unit that switches and connects the batteries in parallel or in series according to the terminal voltage of the battery detected by the battery voltage detection unit 5.

Reference numeral 7 is a current limiting resistance insertion circuit for inserting a current limiting resistance in series in a battery in which a current limiting resistance is connected in parallel or in series according to the terminal voltage of the battery, and 7A is a current limiting resistance having a different resistance value depending on the terminal voltage of the battery. Is a resistor selection switching unit for connecting in series to batteries connected in parallel or in series.

An output frequency switching unit 8 switches the output frequency for driving the stepping motor according to the terminal voltage of the battery. Reference numeral 9 denotes an excitation system switching unit which switches to the two-phase excitation system when releasing pressure when the shutoff valve is opened, according to a control signal from the motor control circuit 10. Further, the output frequency switching unit 8 switches the frequency to a small value when releasing the pressure when the shutoff valve is opened, according to the control signal of the motor control circuit 10 as necessary.

In the embodiments of FIGS. 1 and 2, the thick solid line arrow indicates the flow of power supply, and the thin solid line arrow indicates the flow of electric signals. In both of the embodiments shown in FIGS. 1 and 2, since the battery 4 is composed of a plurality of batteries, the battery connection switching unit 6 for switching and connecting them in series and parallel is provided. However, when only one battery is provided, , The battery connection switching unit 6 is unnecessary, and the battery 4 to the current limiting resistor insertion circuit 7 (in the case of FIG. 1) or the resistor selection switching unit 7 is used.
Power is directly supplied to A (in the case of FIG. 2).

FIG. 3 is a diagram showing an operation example of the above-mentioned embodiment. Based on the result of the voltage detection of reference numeral 11, the batteries are designated by reference numerals 12 and 13.
The parallel connection is made as shown in FIG. 2 or the series connection is made as shown by reference numerals 14 and 15 when the terminal voltage of the battery is low.

When the terminal voltage is high, resistors having a large resistance value such as reference numerals 16 and 18 are selectively connected, and when the terminal voltage is low, resistors having a small resistance value such as reference numerals 17 and 19 are selectively connected. .

When the mechanical load of the shut-off valve is large, the excitation system is switched to two-phase excitation with reference numerals 20 to 23, and when the load is small, one-phase excitation is performed. Furthermore, the frequency is selected to an appropriate value according to the terminal voltage of the battery or the mechanical load of the shutoff valve (reference numerals 24 to 27). In this way, reference numerals 12, 16, 20, 24 and 13, 17, 21, 25
And 14, 18, 22, 26 and 15, 19, 23, 2
The stepping motor 3 is driven by selecting the flow of four driving methods of No. 7.

[0035]

Since the present invention is configured as described above, the power supplied to the step motor is saved when the terminal voltage of the battery is high, and the power supplied to the step motor is reduced when the terminal voltage becomes low. Since the battery can be used up to a low voltage by covering the battery, it is possible to make effective use of the electric power of the battery, to extend the battery life, and to reliably open and close the shutoff valve.

Further, when the load on the shutoff valve is large, the force of the stepping motor can be increased, so that certainty of the operation can be expected also in this respect.

[Brief description of drawings]

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

FIG. 2 is a block diagram of a second embodiment of the present invention.

FIG. 3 is a diagram for explaining the operation of the embodiment of the present invention.

[Explanation of symbols]

 1 Shut-off valve 2 Safety type gas meter 3 Stepping motor 4 Battery 5 Battery voltage detection unit 6 Battery connection switching unit 7 Current limiting resistor insertion circuit 7A Resistance selection switching unit 8 Output frequency switching unit 9 Excitation method switching unit 10 Motor control circuit

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[Procedure amendment]

[Submission date] April 7, 1992

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 1

[Correction method] Change

[Correction content]

[Figure 1]

[Procedure Amendment 2]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 2

[Correction method] Change

[Correction content]

[Fig. 2]

Claims (4)

[Claims] 1. A drive system for a stepping motor for opening and closing a shutoff valve, comprising a battery for a power source, a battery voltage detector for measuring the terminal voltage of the battery, and an operation according to the output of the battery voltage detector. At least two of the following power feeding force control means of (a) to (c) are provided, and a drive system of a shut-off valve action stepping motor. (A) A power feeding force control means comprising a current limiting resistor insertion circuit that connects a current limiting resistor to the power feeding circuit when the terminal voltage of the battery is above a certain level and removes the current limiting resistor when the terminal voltage is below a certain level. (B) A power feeding force control means as an output frequency switching unit for increasing the frequency for driving the stepping motor when the terminal voltage of the battery is above a certain level and decreasing the frequency for driving the stepping motor when below a certain level. (C) A feeding power control means comprising an excitation system switching section that sets the excitation system for driving the stepping motor when the terminal voltage of the battery is above a certain level to one-phase excitation and to the two-phase excitation when below a certain level. 2. A drive system for a stepping motor for shut-off valve operation, wherein the following power feeding force control means of (a ′) is a requirement instead of the power feeding force control means of (a) of claim 1. (A ′) A power feeding force control means comprising a resistor selection switching unit that prepares current limiting resistors having different resistance values and selects and uses the resistance value of the current limiting resistor according to the terminal voltage of the battery. 3. A plurality of batteries for power supply, wherein in addition to the feeding power control means of claim 1 or 2, the following feeding power control means (d) is added, and these feeding power control means are provided. (I)
A drive system of a stepping motor for operating a shutoff valve, comprising at least two of (a ') to (d). (D) A power feeding force control means comprising a battery connection switching unit that connects batteries in parallel when the terminal voltage of the batteries is above a certain level and connects them in series when the terminal voltage of the batteries is below a certain level. 4. In addition to the feeding power control means of claim 1, 2 or 3, the following feeding power control means (e) and (f) are added, and these feeding power control means (a) are added. ) (I ') ~ (F)
At least one of (e) and (e), and (e)
A safety type gas meter characterized by having one of the items other than (f). (E) A power feeding force control means including an output frequency switching unit that reduces the frequency for driving the stepping motor when the pressure is released from the valve and increases the drive frequency when the valve is opened and closed. (F) A two-phase excitation system is used when depressurizing an opening valve that requires a large force to drive the shutoff valve, and a one-phase excitation system is used when opening and closing the valve. Force control means.