JPH024789B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a drive device for an electromagnetic pump used for supplying fuel oil to a heater, etc.

[Prior Art] FIG. 7 is an electronic circuit diagram showing a conventional driving device for an electromagnetic pump, and shows a rectifying circuit 20, an electromagnetic pump 10 represented by an electromagnetic pump coil P, and It is composed of an intermittent control section 30.

The rectifier circuit 20 has a bridge configuration rectifier SR1~
It includes SR4 and a smoothing capacitor _C0 , and one end of the electromagnetic pump coil P is connected to the positive terminal 2 of the rectifier circuit 20.
Connected to 1.

In the intermittent control section 30, the control rectifier SCR
The anode of No. 1 is connected to the remaining end of the electromagnetic pump coil P, and the cathode is connected to the negative terminal 23 of the rectifier circuit. One end of the resistor R1 is connected to a terminal 21, and the other end is connected to a terminal 23 via a Zener diode ZD.

A resistor R2 is connected to the junction of the resistor R1 and the Zener diode ZD, and the other end is connected to a terminal 23 via a capacitor C1 on the one hand and a trigger diode TD1 and a resistor R3 on the other hand.
It is connected to the. The gate of the controlled rectifier SCR1 is connected to the intersection of the trigger diode TD1 and the resistor R3.

The anode of control rectifier SCR2 is resistor R4
and a terminal 21 via a variable resistor VR1, and its cathode is connected to a terminal 23. The anode of the controlled rectifier SCR2 further includes:
On the one hand, a controlled rectifier element via capacitor C2
It is connected to the anode of SCR1, and on the other hand to terminal 23 via trigger diode TD2 and resistors R5 and R6. Resistors R5 and R6
The junction of is connected to the gate of the controlled rectifier SCR2.

The operation of the conventional drive device shown in FIG. 7 will be explained below.

When the power is turned on, the controlled rectifier SCR
Both SCR1 and SCR2 are in a cutoff state, and no current flows through the electromagnetic pump coil P.

The positive voltage at terminal 21 charges capacitor C1 through resistors R1 and R2. The power supply for capacitor C1 is a Zener diode
Since it is stabilized by ZD, capacitor C
The charging characteristics of 1 are not affected by voltage fluctuations at terminal 21.

When the charging voltage of the capacitor C1 reaches a predetermined level, that is, the trigger voltage of the trigger diode TD1, a trigger pulse is generated from the trigger diode TD1 and enters the gate of the controlled rectifier SCR1.
Control rectifying element SCR1 is made conductive, and energization of electromagnetic pump coil P is started.

Simultaneously with the conduction of the control rectifying element SCR1, charging of the capacitor C2 is started via the resistor R4 and the variable resistor VR1 with the polarity shown.

When the capacitor C2 reaches a predetermined level, that is, the trigger voltage of the trigger diode TD2, a trigger pulse is output from the trigger diode TD2 and enters the gate of the controlled rectifier SCR2.
SCR2 becomes conductive.

At this time, the voltage of the capacitor C2 is discharged through the controlled rectifying element SCR2, and the voltage of the capacitor C2 is discharged through the controlled rectifying element SCR1.
cut off. In this case, the conduction time of the controlled rectifier SCR1 is adjusted by the variable resistor VR1.

Further, it is needless to explain in detail that the controlled rectifying element SCR2 is cut off at the time of the next conduction of the controlled rectifying element SCR1, and this on/off operation is continued repeatedly, and the electromagnetic pump coil P is turned on/off. Pumping action is performed by turning off.

[Problems to be Solved by the Invention] The ON and OFF times of the current flowing to the electromagnetic pump coil P in FIG. and capacitor C2
When the controlled rectifier SCR2 is conductive and the controlled rectifier
This is done by setting the time when SCR1 is shut off.

That is, in order to set the on and off times of the current flowing to the electromagnetic pump coil P, two capacitors are required to influence the time settings.

In general, among the circuit elements mentioned above, the capacitance of a capacitor is particularly prone to variation, and when two capacitors are used as described above,
For each electromagnetic pump drive device that is manufactured, variations tend to occur in the ON and OFF time settings for the current flowing through the electromagnetic pump coil P, and in order to correct for these variations, it is necessary to It is necessary to correct the variations on both sides.

Further, the capacitance of a capacitor increases as the ambient temperature rises, and the temperature characteristics of the capacitance also vary from capacitor to capacitor, so the on/off time settings for the current flowing to the electromagnetic pump coil P change. Even in taking such measures for temperature compensation, it is necessary to take measures that take into consideration the variations in capacitance of both capacitors, which has the disadvantage that the measures become extremely complicated.

Particularly, when mass-producing the above drive device, it is necessary to average out and compensate for variations in capacitor capacitance during manufacturing and variations in temperature characteristics. Therefore, the electromagnetic pump has the disadvantage that variations in the discharge flow rate depending on the ambient temperature inevitably increase.

An object of the present invention is to further reduce the influence of temperature changes on the discharge flow rate even if there is a change in ambient temperature,
Another object of the present invention is to provide an electromagnetic pump driving device that can reduce variations in the influence of temperature changes on the discharge flow rate for each product.

[Means for solving problems] The present invention consists of the following configuration.

The solenoid 5 that drives the piston that performs the pumping action is excited by the output current from the power supply, and the on/off control of the current flowing to the solenoid is controlled by the transistor TR2 in response to the control signal from the square wave oscillation circuit 3. In the drive device that performs on/off control, the rectangular wave oscillation circuit is configured such that power from the charging power supply is connected to a single integrating capacitor C via a charging resistor circuit 3A and a diode D2.
4, and a discharging circuit in which the charged power is discharged to the common circuit via the switching element TR1 and the discharging resistor circuit,
and detecting the period from the start of charging to the point in time when the integrating capacitor reaches a predetermined high voltage due to the charging, transmitting the on signal to the transistor during that period, and simultaneously turning off the switching element during that period. When the charging voltage reaches the predetermined high voltage, the switching element is made conductive to start the discharging, and from the start of the discharging, the voltage value of the integrating capacitor reaches the predetermined high voltage. Detecting the period until a low voltage is reached, transmitting the off signal to the transistor during that time, and simultaneously keeping zero potential between the charging resistor circuit and the diode during that time, repeating the above on/off operation. The charging resistor circuit has a circuit configuration in which the electrical resistance value of the charging resistor circuit changes by including a thermal element RT whose electrical resistance changes depending on the ambient temperature. There is.

[Function] When the transistor is turned on by the on signal from the square wave oscillation circuit, the output current from the power supply flows to the solenoid, energizing the solenoid, and
The excitation drives a piston in the pump. Conversely, when the on signal disappears, the current flowing through the solenoid is turned off in that transistor, the electromagnetic force disappears, and the piston returns to its original position due to spring force or the like. Subsequently, an ON signal is again transmitted from the rectangular wave transmitting circuit, and the above action is repeated, and this repetition becomes the pumping action of the electromagnetic pump.

The on/off transmission from the rectangular wave transmission circuit in the above pump action is as follows.

Power from a charging power supply charges a "single" integrating capacitor through a charging resistor circuit and a diode, and the voltage from the start of charging to the point at which the integrating capacitor reaches a predetermined high voltage is measured. It detects the interval and sends an on signal to the transistor during that time.

Also, while transmitting the on signal at the same time,
Set the switching element to OFF. This prevents discharge from the integrating capacitor via the discharge resistor circuit during the charging operation.

Following the transmission of the above-mentioned on signal, the switching element is made conductive from the time when the charging voltage in the integrating capacitor reaches a predetermined high voltage, and the discharging of the integrating capacitor is started. The period until the voltage value of the capacitor reaches a predetermined low voltage value is detected, and the above-mentioned off signal is transmitted during that period.

At the same time, while the off signal is being transmitted, zero potential is maintained between the charging resistor circuit and the diode. This is to ensure that charging from the charging power source to the integrating capacitor is stopped during this discharging action.

In the above action, if the ambient temperature changes, the viscosity of the oil discharged from the electromagnetic pump and the electrical resistance of the solenoid coil will change, so if the above on time and off time are fixed, the oil discharge from the electromagnetic pump will The discharge flow rate of oil per unit time changes.

To deal with this case, the charging resistance circuit in the configuration of the present invention includes a heat-sensitive element whose electrical resistance changes depending on the ambient temperature, so that the electrical resistance value of the charging resistance circuit changes depending on the ambient temperature. It has a changing circuit configuration.

This increases the resistance value of the charging resistor circuit as the ambient temperature decreases, and as a result, the electromagnetic pump The amount of oil discharged per stroke is kept constant.

Further, the effect on the change in the amount of oil discharged due to the change in the ambient temperature is the viscosity of the oil and the electrical resistance of the solenoid coil, and is affected by the change in capacitance of the integrating capacitor due to temperature.

However, as described below, since there is only one integrating capacitor, the change in the capacity of the integral capacitor has almost no effect on the change in the oil discharge amount.

That is, the integrating capacitor sets the on-time as described above, and then the same integrating capacitor also sets the off-time.

This means that even if the capacitance of the integrating capacitor increases (or decreases) due to a change in ambient temperature, the on-time will increase (or decrease) in proportion to the increase (or decrease).
And the changed capacitance of the same integrating capacitor is
In proportion to the increase (or decrease) in capacity, the off time is increased (or decreased) in the same proportion.

Here, an increase in the on-time is proportional to an increase in the amount of oil discharged per unit time, and an increase in the off-time is inversely proportional to the rate of increase and reduces the amount of oil discharged per unit time. be.

Therefore, the increment (or decrement) of its on time and the increment (or decrement) of its off time.
This means that the changes in oil discharge amount per unit time are mutually offset.

What is important here is that this type of electromagnetic pump drive device is often mass-produced.

In this way, in a mass-produced electromagnetic pump drive device, the factors that affect the amount of oil discharged from the electromagnetic pump per unit time by the ambient temperature are listed above in descending order of influence. Changes in the viscosity of the oil, changes in the resistance of the solenoid coil, and changes in the capacitance of the integrating capacitor have a particularly large effect.

Of these, the characteristics of changes in oil viscosity and solenoid coil resistance due to ambient temperature do not vary much among mass-produced electromagnetic pumps. On the other hand, the temperature characteristics of the capacitance of an integrating capacitor vary widely depending on the product. Furthermore, there are large variations in the capacitance of the integrating capacitor during manufacturing.

For this reason, all drive devices mass-produced as described above should take into account the effects of changes in oil discharge amount due to changes in oil viscosity and solenoid coil resistance due to changes in ambient temperature. The same value is compensated in the charging resistor circuit. That is, it is not necessary to strictly determine compensation values for each drive device and to compensate for the temperature due to the viscosity of the oil and the resistance change of the solenoid coil.

On the other hand, by using a single integral capacitor, which has temperature characteristics that vary depending on the drive device, as described above, the capacitance change of the same integral capacitor will be longer than the on-time and off-time. However, by applying an influence at the same rate, it is possible to substantially cancel out the influence on the change in oil discharge amount per unit time.

[Example] Hereinafter, the present invention will be explained based on Examples.

FIG. 1 shows an electronic circuit diagram of an embodiment of an electromagnetic pump driving device according to the present invention. 3, a transistor amplifier circuit 4, and a solenoid 5 that drives a piston (not shown) in an electromagnetic pump.

A household 100V power supply is connected to terminals 1a and 1b, terminal 1b is a terminal on the common circuit side, and 3a, 4a and 4b are also terminals,
The terminal 3a functions by being connected to the terminal 1b as necessary.

D1, D2, and D3 are diodes, ZD is a Zener diode, R1, R2...R14 are each a resistor, and in particular, RT is a heat-sensitive element such as a thermistor whose electrical resistance changes depending on the ambient temperature. IC2 is a comparator, and in this case, connections to the power supply and common circuits in comparators IC1 and IC2 are omitted.

Also, TR1 and TR2 are transistors, VR
1 and VR2 are variable resistors, C1 and C2 are smoothing capacitors, C3 is a noise prevention capacitor, C4 is an integrating capacitor, and resistor R6, thermal resistor RT, and resistor R7 connect the charging resistor circuit 3A. consists of resistor R12, variable resistor
VR1, resistor R13, and variable resistor VR2 constitute a discharge resistance circuit, and each solid line indicates wiring.

The electromagnetic pump (not shown) in this embodiment shown in FIG. 1 is exemplified by a pump that discharges fuel oil in a household heater.

Hereinafter, in the configuration of the embodiments of the present invention,
The effect will be explained.

The AC power supply voltage applied to the terminals 1a and 1b is half-wave rectified in the rectifier circuit 1, and the rectified and smoothed voltage in the wiring 1c is applied as it is from the terminal 4a to the solenoid 5 side on one side, and on the other side. , the current generated from the voltage is applied to the wiring 2a via the resistor R2.

The voltage at wiring 2a is a Zener diode
The voltage is stabilized by the presence of ZD, and the stabilized voltage is, on the one hand, resistor R8
The voltage Vh is initially applied to the wiring 3c via
On the other hand, due to the voltage occurring in the wiring 2a, a current flows into the wiring 3b via the resistor R3, and the wiring 1c flows into the wiring 3b.
A current flows through the resistor R5 due to the voltage generated in the resistor R5, and the voltage of the wiring 3b determined by the current from the resistor R3 side and the current from the resistor R5 side is: From the configuration, the amount of voltage component from the stabilized voltage V2a in the wiring 2a and the unstabilized voltage V1c in the wiring 1c
It is the sum of the component amount of each voltage with the voltage component amount from , and the ratio of the component amount is determined by the respective resistance values of the resistors R3 and R5. Further, the voltage at the wiring 3b is the charging voltage for the integrating capacitor C4.

In such an initial state, the voltage occurring on the wiring 3b charges the integrating capacitor C4 via the charging resistor circuit 3A and the diode D2, increasing the voltage on the wiring 3e.

In this state, the above-mentioned voltage is applied to the wiring 3c.
Vh is generated, and this voltage Vh is also the comparator IC1
It is also the voltage of one input 3g in
In contrast, the other input 3 in comparator IC1
Since h is equal to the voltage at the integrating capacitor C4, the comparator IC1
The voltage at the wiring 3d serving as the output circuit is set to a high level potential.

From this state, when the integration capacitor C4 is sufficiently charged and the voltage of the wiring 3e, that is, the input 3h, reaches the voltage Vh of the input 3g,
The comparator IC1 turns on and drops the voltage on the wiring 3d to a low level (almost zero voltage). As a result, at this time, the base of transistor TR1 also becomes a low level voltage value, so
Transistor TR1 turns on and the voltage across integrating capacitor C4 is applied to resistor R12 and variable resistor.
Discharged to the common circuit via VR1.

Furthermore, since the wiring 3d is at a low level at this time, the potential difference between the voltage at the wiring 3c and the low level voltage at the wiring 3d becomes large, and a larger current flows into the resistor R10.
As a result, in this state, the voltage of the wiring 3c or the input 3g is converted from the above-mentioned voltage Vh to the lower voltage V1.

At this time, since the wiring 3d becomes low level, the wiring 3f connected to the wiring 3d also becomes low level, but due to the presence of the diode D2,
The discharge from the integrating capacitor C4 does not flow toward the wiring 3f, but only toward the discharge resistance circuit 3B.

When the above-mentioned discharge continues and the voltage at the wiring 3e or input 3h eventually drops to the voltage V1 at the input 3g, the comparator IC1, due to its nature, sets the wiring 3d to the initial state again at a high level. do.

Therefore, the voltage at the input 3g becomes Vh again, the transistor TR1 is also turned off, and the integrating capacitor C4 starts charging again, and this state repeats the same cycle as the initial operation described above.

The voltages V3c, V3e and V3d of the wirings 3c, 3e and 3d in the above cycle have characteristics as shown in FIGS. 2, 3 and 4, respectively.

Note that the vertical axis V in each of FIGS. 2, 3, and 4 represents voltage, and the horizontal axis t represents elapsed time.

Here, the voltage V3d at the wiring 3d may be considered as the output of the rectangular wave transmitting circuit 3. However, the voltage V
When 3d directly drives transistor TR2,
This causes a voltage drop in the voltage V3d, so the voltage V3d is outputted to the wiring 4c via the comparator IC2.

The operation of the comparator IC2 will be explained below.As is clear from the above explanation, the voltage change of one input 3i in the comparator IC2 is V in FIG.
3d, and the voltage change of the other input 3j in comparator IC2 is V3e in FIG.
As a result, due to the properties of the comparator IC2, in time a to b (charging time of integrating capacitor C4) in FIGS. 3 and 4,
Since the value of V3d (Figure 4) is greater than the voltage of V3e (Figure 3), the wiring 4c that is the output of the comparator IC2 is at a high level voltage, and the integrating capacitor C4 is discharged. During the period from b to c during which V3d is approximately zero voltage, the wiring 4c repeats a cycle in which the voltage is at a low level, and the voltage characteristic of the wiring 4c becomes V4c.

When the voltage V4c (FIG. 5) of the wiring 4c is at a high level, the transistor TR2 is turned on due to its nature, and the voltage is passed from the terminal 4a to the solenoid 5 to the terminal 4.
When the current flows through the solenoid 5 and the transistor TR2 to the terminal 1b, the electromagnetic force of the solenoid 5 generated by the current attracts the piston in the electromagnetic pump. As a result, the electromagnetic pump performs a pumping action, and the cycle of piston reciprocating motion in the pumping action is the same as the cycle of voltage V4c shown in FIG. 5, and the time required for one cycle is as follows. This is the required time from time a to time c in Figure 4.

As can be understood from the above explanation, the charging time (a to b) in FIG. 3 is such that the smaller the resistance of the charging resistor circuit 3A, the faster the voltage rise in the integrating capacitor C4 reaches the predetermined high voltage Vh. , it enters the next discharge.

That is, the value of the electrical resistance in the charging resistance circuit 3A and the time width (a to b) during which the voltage V4c in FIG. As a result, the time during which the working fluid is pressurized during one stroke of the piston in the electromagnetic pump becomes longer.

In this embodiment, the above property is utilized to prevent the discharge amount of the working fluid from changing depending on the temperature, and the temperature compensation will be explained below.

In the charging resistance circuit 3A, if the respective resistance values of resistors R6 and R7 and heat-sensitive element RT are R6, R7, and RT, first, the parallel resistance circuit portion constituted by resistor R7 and heat-sensitive element RT is The total resistance value RP is 1/RP=1/RT+1/R7 (1), and the series resistance value R composed of the total resistance value RP and the resistance value R6 has the following relationship: R=RP+R6 (2).

Here, a thermistor is used as the heat-sensitive element RT, and the resistance values of the thermistor and resistors R6 and R7 are as follows: Typical resistance value of thermistor: 77KΩ at -20℃ 30KΩ at 0℃ R6 51KΩ R7 30KΩ Charging resistance circuit 3A at each temperature When the total resistance R of is determined from equations (1) and (2), its characteristic A
is as shown in Figure 6. However, the horizontal axis θ in FIG. 6 indicates the ambient temperature (° C.).

As can be seen from this characteristic, the value of the overall resistance R increases rapidly as the temperature decreases. This is consistent with the property of rapidly increasing viscosity at low temperatures.

Here, the increase in viscosity increases the flow resistance when being discharged from the electromagnetic pump, and as a result, the working fluid (fuel oil in this example) from the electromagnetic pump is discharged at a constant rate. In order to achieve this, it is necessary to increase the time during which the piston is pressurized in proportion to the temperature drop of the working fluid.

In other words, characteristic A in FIG. 6 shows that the total resistance value R of the charging resistance circuit 3A has a value similar to the viscosity increase curve of the working fluid. circuit 3A
This increases the overall resistance value R of the pump, thereby increasing the time during which the piston is pressurized in the electromagnetic pump.

Furthermore, since the temperature characteristics of viscosity in these working fluids differ depending on the working fluid, the temperature characteristics of this total resistance value R can also be easily matched with the temperature characteristics of each viscosity. This is desirable.

On the other hand, in this embodiment, by changing only the resistor R7 in the charging resistance circuit 3A, it is possible to greatly change the characteristics of only the low temperature portion.

That is, as shown in characteristic B in Fig. 6, characteristic A
When only the resistance value R7 is changed from 30KΩ to 75KΩ, the total resistance value R hardly changes when the ambient temperature is above 20℃, but its characteristics change rapidly below 20℃. I understand. As a result, the characteristics of the total resistance value R can be freely changed by simply manipulating the resistance value of the resistor R7, and the characteristics can be adapted to the temperature characteristics of the fuel oil.

Furthermore, the resistance of the solenoid coil 5 also changes due to this change in ambient temperature. Therefore, the resistance values of the resistors R6 and R7 can be selected in consideration of the change in resistance of the solenoid coil 5 due to the ambient temperature.

Further, the effect on the change in the oil discharge amount due to the change in the ambient temperature is, next to the viscosity of the oil and the electrical resistance of the solenoid coil 5, the change in the capacitance of the integrating capacitor C4 due to the temperature change.

However, as shown below, since there is only one integral capacitor C4, the change in the oil discharge amount due to the change in the capacity of the integral capacitor C4 has almost no effect on the oil discharge amount change. Become.

That is, the integrating capacitor C4 sets the on-time (between a and b in FIG. 5) as described above, and then the same integrating capacitor C4 also sets the off time (between b and c in FIG. 5). It has become something to do.

This means that even if the capacitance of integrating capacitor C4 increases (or decreases) due to a change in ambient temperature, its on-time will increase (or decrease) in proportion to the increase (or decrease). In addition, when the capacitance of the same integrating capacitor C4 is changed, its off time also increases (or decreases) in proportion to the increase (or decrease) in the capacitance.

Here, an increase in the on-time is proportional to an increase in the amount of oil discharged per unit time, and an increase in the off-time is inversely proportional to the proportion of the increased time, decreasing the amount of oil discharged per unit time. It is in.

Therefore, the increment (or decrement) of its on time and the increment (or decrement) of its off time.
This means that the influence on the change in oil discharge amount per unit time is mutually canceled out.

Regarding the above temperature compensation, in order to be able to variably adjust the amount of fuel oil discharged from the electromagnetic pump within a unit time, the piston in the electromagnetic pump is returned by a built-in spring, and the What is necessary is to make it possible to adjust the time during which it remains as it is, that is, the time width corresponding to the period b to c in FIG. 4.

As understood from FIG. 3, the time width (b to c) is the discharge time of the integrating capacitor C4, and the discharge time is determined by the resistance value of the discharge resistance circuit 3B. In the present invention, by variably adjusting the variable resistor VR1 in the discharge resistance circuit 3B, the discharge time is adjusted and the supply of fuel oil to the heater is adjusted.

The variable resistor VR1 may be adjusted by detecting the room temperature of the room being heated by a heater and controlling its resistance value based on the detected detection signal, or by manually controlling the resistance value. You can also set

Furthermore, if the discharging time of the integrating capacitor C4 cannot be fully adjusted by adjusting only the variable resistor VR1, by connecting new terminals 3a and 1b, the discharging resistor circuit 3B can be adjusted using the resistor R12 and the variable resistor. The circuit configuration is such that the resistance circuit of VR1 and the other resistance circuit consisting of resistor R13 and variable resistor VR2 are provided in parallel, and by adjusting the resistance of variable resistor VR1 or VR2 in the circuit configuration, The discharge time can be adjusted over a wider range.

Note that the electromagnetic pump drive device in the above embodiment is described for driving an electromagnetic pump for fuel supply in a heater, but it is easily understood that the drive device can be used for electromagnetic pumps in general. be understood.

[Effects of the Invention] As is clear from the above description, the effects of the present invention are as follows.

When a change occurs in the ambient temperature, among the factors that cause a large change in the oil discharge flow rate per unit time in an electromagnetic pump are a change in the viscosity of the oil, a change in the resistance value of the solenoid coil 5, and a change in the capacitance of the integrating capacitor 5. The charging resistor circuit 3A is used for various factors such as changes in oil viscosity and changes in the resistance value of the solenoid coil 5, which have small variations in characteristics from product to product.
is equipped with a circuit that detects changes in ambient temperature and corrects its resistance value, and the correction value is determined by each drive device because there is little variation from product to product in the viscosity change characteristics of the oil and the resistance value change characteristics of the solenoid coil 5. Temperature compensation is made possible by applying the same correction value to each case.

On the other hand, regarding the influence of the variation on the above-mentioned discharge flow rate of the integrating capacitor C4, which has a large variation between products and a large variation in the temperature characteristics of its capacitance, the above-mentioned on-board The configuration is such that the same integrating capacitor C4 is involved in setting the time and the above-mentioned off time, thereby preventing the temperature change of the discharge flow rate from being affected.

Therefore, the drive device for this electromagnetic pump can easily compensate for the temperature of the oil discharge amount per unit time of mass-produced electromagnetic pumps, even if conventional capacitors are used, which has a large variation in products. It is.

[Brief explanation of drawings]

FIG. 1 shows an electronic circuit diagram of an embodiment of an electromagnetic pump driving device according to the present invention, and FIGS. Wiring 3c, 3e, 3d in Figure 1
and 4c, respectively.
FIG. 6 shows the electrical resistance characteristics of the charging resistor circuit 3A in FIG. 1, and FIG. 7 shows an electronic circuit diagram of a conventional electromagnetic pump driving device. The main symbols used in the examples are as follows. 1... Rectification smoothing circuit, 1a and 1b... terminal, 2... voltage stabilization circuit, 3... square wave oscillation circuit, 3A... charging resistor circuit, R6 and R7...
Resistor, RT...thermal element, 3B...discharge resistance circuit, R12 and R13...resistor, VR1 and VR2...variable resistor, 3a...terminal, 3g,
3h, 3i and 3j...input, 4...transistor amplifier circuit, 5...solenoid, C4...integrating capacitor.

Claims (1)

[Claims] 1. The solenoid 5 that drives the piston that performs the pumping action is excited by the output current from the power source, and the on/off control of the current flowing to the solenoid is controlled by the square wave oscillation circuit 3. In a drive device in which a transistor TR2 performs on/off control based on a signal, the rectangular wave oscillation circuit is configured such that power from a charging power supply is integrated into a single integral circuit through a charging resistor circuit 3A and a diode D2. Capacitor C
4, and a discharging circuit in which the charged power is discharged to the common circuit via the switching element TR1 and the discharging resistor circuit,
and detecting the period from the start of charging to the point in time when the integrating capacitor reaches a predetermined high voltage due to the charging, transmitting the on signal to the transistor during that period, and simultaneously turning off the switching element during that period. When the charging voltage reaches the predetermined high voltage, the switching element is made conductive to start the discharging, and from the start of the discharging, the voltage value of the integrating capacitor reaches the predetermined high voltage. Detecting the period until the voltage reaches a low voltage, transmitting the off signal to the transistor during that time, and simultaneously keeping zero potential between the charging resistor circuit and the diode during that time, repeating the above on/off operation. The charging resistor circuit has a circuit configuration in which the electrical resistance value of the charging resistor circuit changes by including a thermal element RT whose electrical resistance changes depending on the ambient temperature. Device.