JP3452417B2 - Proportional valve drive - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a proportional valve drive device for performing PWM control.

[0002]

2. Description of the Related Art For example, in a gas warm air heater, a combustion amount for maintaining a detected room temperature at a set temperature is calculated, and the opening of a proportional valve is controlled so as to obtain the combustion amount. For this proportional valve control, since there is little hysteresis and it is necessary to change the opening quickly, the following proportional valve drive device has been conventionally used.

As shown in FIG. 9, a conventional proportional valve driving device B has a valve body, a plunger, a spring, and an electromagnetic coil 902.
DC proportional power supply 901 and electromagnetic coil 902
The ON time of the transistor 903 connected between and is shortened when the weak combustion is instructed, and the ON time of the pulse 904 applied to the base is shortened when the strong combustion is instructed. 5 (a)}, and a drive circuit 905 for PWM-controlling the on-duty of the transistor 903. As described above, since the plunger vibrates by PWM controlling the electromagnetic coil 902, the hysteresis is reduced.

[0004]

In the gas warm air heater using the above conventional proportional valve driving device, since the vibration of the plunger is large in the strong combustion region, the sliding contact noise due to the sliding of the plunger is generated. There is a problem that the size becomes large and the user feels uncomfortable (see (a) of FIG. 5).

An object of the present invention is to provide a proportional valve drive device that reduces noise generated when the proportional valve is PWM-controlled.

[0006]

[Means for Solving the Problems] In order to solve the above problems,
The present invention has the following configurations. (1) A proportional valve for controlling the passage amount of a fluid, a semiconductor element connected between a direct current power source and a coil of the proportional valve, to which a pulse described later is input, and a case where the passage amount of the fluid is reduced. a proportional valve driving apparatus and a driving means to shorten the oN time of the pulse outputted, for PWM controlling the duty cycle of the semiconductor device by increasing the pulse on-time in the case of many, throughput of the fluid Less system
In the control area, place a capacitor on both ends of the coil of the proportional valve.
Not connected, it is provided a capacitor connecting means for connecting said capacitor across the coil by the passage of the fluid is large control range.

(2) A valve body facing a valve seat formed in the gas passage, a plunger for connecting the valve body, a spring for urging the plunger, and an electromagnetic wave for exciting the plunger according to the amount of energization. a proportional valve having a coil, is connected between the DC power supply and the electromagnetic coil, a semiconductor element will be described later pulse is input, and shortening the oN time of the output pulse in the case of instructing the small gas flow rate, In order to indicate a large gas flow rate , in a proportional valve drive device having a microcomputer for PWM-controlling the duty of the semiconductor element by lengthening the ON time of the pulse , the small gas flow rate Instruction
If this is the case, apply a coil to both ends of the electromagnetic coil of the proportional valve.
Without connecting the capacitor, it is provided a capacitor connecting means for connecting said capacitor across said electromagnetic coil when a large gas flow rate is indicated.

(3) With the configuration of (2) above, the capacitor connecting means connects the emitter to one side of the electromagnetic coil, and when the large gas flow rate is indicated, the micro
A transistor switching signal is input to the base from the computer, and a capacitor connected to the other end is connected at one end to the other side of the electromagnetic coil to the collector of the transistor, the collector of the transistor - and a diode connected between the emitter It is composed of

[0009]

[Action]

[Claim 1] The capacitor connecting means does not connect a capacitor to both ends of the coil of the proportional valve in the control region where the amount of passage of the fluid is small. The driving means increases or decreases the on-time of the pulse to be output to increase the duty of the semiconductor element to P.
With WM control, the proportional valve shows an opening degree commensurate with the duty, and an amount of fluid commensurate with the ON time of the pulse passes through the proportional valve.

In a control region where a large amount of fluid passes, the capacitor connecting means connects a capacitor to both ends of the coil of the proportional valve, so that a current having a smooth waveform flows through the coil.
The drive means controls the average amount of current flowing in the coil by increasing or decreasing the on-time of the pulse to be output, and the proportional valve shows the opening degree corresponding to the on-time of the pulse, and the amount of fluid corresponding to the on-time of the pulse. Passes through the proportional valve.

[0011] Microcomputer [describe Claim 2], in the case of instructing the small gas flow rate by shortening the ON time of the output pulse, the pulse on-time in the case of a large gas flow rate for the finger <br/> shown The duty of the semiconductor element is PWM-controlled by increasing the value of. Capacitor connection
The continuation means is used to turn on the proportional valve when a small gas flow rate is indicated.
Large gas flow rate without connecting capacitors to both ends of magnetic coil
Connect capacitors to both ends of electromagnetic coil when instructed
To do. The electromagnetic coil of the proportional valve excites the plunger according to the duty of the semiconductor element, the proportional valve shows the opening corresponding to the pulse on-time, and the amount of gas corresponding to the pulse on-time passes through the proportional valve. To do.

When a large gas flow rate is indicated, the capacitor connecting means connects a capacitor to both ends of the electromagnetic coil. Therefore, a current with a smoothed waveform flows through the electromagnetic coil. The semiconductor drive means controls the average amount of current flowing through the electromagnetic coil by increasing or decreasing the on-time of the pulse to be output, and the proportional valve shows the opening corresponding to the on-time of the pulse.
An amount of gas commensurate with the on time of the pulse passes through the proportional valve.

[Claim 3] When a switching output is input to the base from the microcomputer when a large gas flow rate is indicated, the collector and emitter of the transistor become conductive, and the electromagnetic coil The capacitor is connected to both ends of. A diode is connected between the collector and emitter of the transistor.

[0014]

EFFECTS OF THE INVENTION [Claim 1] In the control area where the amount of passage of the fluid is small, the capacitor connecting means
Does not connect a capacitor to both ends of the proportional valve coil , and the capacitor connection means is proportional in the control area where a large amount of fluid passes.
By connecting a capacitor to both ends of the valve coil , a smoothed waveform current is passed through the coil, the proportional valve is opened to match the pulse on-time, and an amount of fluid corresponding to the pulse on-time is passed. It is a configuration that allows it.

In the control area where the passage amount of fluid is small, the capacitor
Sensor connection means connect capacitors to both ends of the proportional valve coil.
The drive means does not control the duty of the semiconductor element by PWM.
It is a control structure. Therefore, the current flowing through the proportional valve is small.
Secure the plunger in the control range where the proportional valve does not move smoothly.
Can vibrate and prevent hysteresis of proportional valve
It In a control area where a large amount of fluid passes, the plunger
Vibration of the valve is reduced and the noise generated by the proportional valve is increased.
Contact noise caused by the sliding of the charger.
No discomfort to users. Control with a large amount of fluid passing
In the region, even if a smooth waveform current is applied to the coil,
The rate of change due to sterisis is small and should not be a problem
Yes.

[0016] When [charged for claim 2, the microcomputer is that instructs a large gas flow rate, the capacitor connecting means for connecting the capacitor across the electromagnetic coil. Therefore, a current having a smoothed waveform flows through the electromagnetic coil. The micro computer controls the average amount of current flowing through the electromagnetic coil by increasing or decreasing the on-time of the pulse to be output, and the proportional valve shows the opening corresponding to the on-time of the pulse, and the proportional valve Gas passes through the proportional valve. Therefore, if you instruct a large gas flow rate, vibration of the plunger is reduced, it is possible to reduce noise {sliding sound due to sliding of the plunger} emitted by the proportional valve, the user No discomfort. Note that when you instruct a large gas flow rate, not a fraction is small problem varies with hysteresis because the amount of current flowing even by applying a current smooth waveform to the electromagnetic coil are many.

[0017] The microcomputer instructs the small gas flow rate
If you that is, without connecting the capacitor capacitor connection means at both ends of the electromagnetic coils of the proportional valve, microcomputers
In this configuration, the duty ratio of the semiconductor element is PWM-controlled. Therefore, the plunger can be reliably vibrated in the small gas flow rate range where the current flowing through the proportional valve is small and the proportional valve does not move smoothly, and hysteresis of the proportional valve can be prevented.

[Claim 3] When the pulse input from the microcomputer to the semiconductor element is on and the collector-emitter of the transistor is conductive, the capacitor is charged through the transistor and input to the semiconductor element. When the pulse applied is off, the capacitor discharges through the diode. Therefore, a current having a smoothed waveform can be passed through the electromagnetic coil.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention (corresponding to claims 1 to 3) will be described with reference to FIGS. As shown in FIGS. 1 to 4, a gas warm air heater A is disposed in a combustor 1 that is supplied with gas and burns, and a gas pipe 10 that supplies the gas to the combustor 1, and supplies the amount of supplied gas. A proportional valve 2 for controlling, a microcomputer 3, a capacitor connection circuit 4, a controller 6 having a proportional valve drive circuit 5 and the like are provided. Further, 7 is a housing, 81 is an operation switch, 82 is a thermocouple, and 8
3 is a temperature setter for setting the room temperature, 84 is a room temperature sensor for detecting the room temperature, 85 is a convection fan for blowing warm air, 86,
Reference numeral 87 is a solenoid valve, and 88 is an ignition electrode.

The combustor 1 includes a mixing chamber 11 for mixing gas ejected from a nozzle n arranged downstream of the air guide passage 77 and room air 71 guided by the air guide passage 77, and a ceramic combustion plate. 12 and the combustion cylinder 13 in which the ignition electrode 88, the thermocouple 82, etc. are arrange | positioned. The nozzle n is formed at the tip of the gas pipe 10 in which the solenoid valves 86, 87 and the proportional valve 2 are sequentially arranged.

The proportional valve 2 is, as shown in FIG. 6, a primary pressure chamber 2
The valve body 21 is attached to the diaphragm 202 that is displaced according to the pressure of 01, and the governor mechanism that cancels the fluctuation of the pressure of the gas flowing into the primary pressure chamber 201 is provided. still,
The body 200 is formed by aluminum die casting (press).

The valve body 21 is displaced according to the pressure in the primary pressure chamber 201, and the valve opening degree (gas passage) between the valve body 21 and the valve seat 22 is adjusted. For example, when the pressure in the primary pressure chamber 201 rises, a force that displaces the valve body 21 upward in the drawing acts, and the valve opening between the valve body 21 and the valve seat 22 is narrowed. or,
When the pressure in the primary pressure chamber 201 decreases, a force for displacing the valve body 21 downward in the drawing acts and the valve opening degree is expanded.

In this proportional valve 2, a plunger 23 and an electromagnetic coil 24 for applying a displacement force to the valve body 21 are assembled inside and outside the sliding cylinder 203. The electromagnetic coil 24 is mounted above the valve body 21 in the figure, and energization is controlled by the proportional valve drive circuit 5.

A displacement force is applied to the plunger 23 according to the amount of current flowing through the electromagnetic coil 24, and the valve body 21 is displaced by the displacement force. Specifically, when the amount of current flowing through the electromagnetic coil 24 is increased, the force that urges the valve body 21 downward in the drawing increases, and the valve opening degree increases.

Reference numeral 25 is a spring for urging the valve body 21 upward in the drawing (direction in which the valve opening is narrowed), and 26 is the diaphragm 20.
2 is a spring for urging 2 downward, 27 is a plunger 23
Is a spring for urging the plunger 23 upward in the figure, 28 is a spring for urging the plunger 23 downward in the figure, and 29 is an adjusting screw for adjusting the urging force of the spring 28.

The microcomputer 3 includes an operation controller 3
1, a switching unit 32, a temperature control unit 33 and the like. When the operation switch 81 is turned on, the operation control unit 31 instructs the solenoid valve drive circuit 301 to open the solenoid valves 86 and 87, and instructs the igniter circuit 302 to turn on the ignition electrode 88 for a predetermined time. Power is supplied to ignite the combustor 1. When the output voltage of the thermocouple 82 becomes less than a predetermined value during combustion, the solenoid valves 86 and 87 are closed to extinguish the combustor 1. When the operation switch 81 is turned off, the solenoid valves 86 and 87 are closed to extinguish the combustor 1.

The temperature control unit 33 receives the outputs of the room temperature sensor 84 and the temperature setter 83, and in the initial stage of ignition,
Set the heating capacity to level 8 and instruct the forced strong combustion. When the forced strong combustion period ends and the temperature control operation starts, the heating capacity (level 1 to level 7) is based on the detected room temperature detected by the room temperature sensor 84 and the set temperature set by the temperature setter 83. To decide.

When the heating capacity determined by the temperature control unit 33 is large, the switching unit 32 has a level of 5 to 5 in the present embodiment.
8}, the switching output 321 is sent to the capacitor connection circuit 4. The proportional valve drive circuit 5 includes a power transistor 52,
A transistor drive circuit 53 that drives the power transistor 52 and a limiting resistor 54 that limits the current. The power transistor 52 has a collector connected to a DC power supply (+ 3V; stabilization) 51, an emitter connected to one side 211 of the proportional valve 2, and a pulse input to the base.

A signal corresponding to the heating capacity determined by the temperature control unit 33 is input to the transistor drive circuit 53. The higher the level of the heating capacity, the longer the ON time of the pulse p to be output and the power transistor. The on-duty of 52 is PWM-controlled. In this embodiment, the pulse p
Frequency is 500Hz (cycle 2mS), but 150
You may select in Hz-1000Hz.

The capacitor connection circuit 4 has an emitter 411.
41 connected to the one side 211 of the electromagnetic coil 24, the plus side 421 to the collector 412 of the transistor 41, and the minus side 422 to the electromagnetic coil 24.
Of the transistor 41, a diode 44 connected between the collector 412 and the emitter 411 of the transistor 41, and a transistor drive circuit 43 for driving the transistor 41.

In the transistor 41, when the low level signal 410 is input from the transistor drive circuit 43, the collector 412 and the emitter 411 are electrically connected, and a circuit for charging the electrolytic capacitor 42 is formed. Further, the diode 44 is connected in the direction opposite to the energization direction of the transistor 41, and thus a circuit for discharging the electrolytic capacitor 42 is formed. Therefore, when the low level signal 410 is input to the transistor 41 and the power transistor 52 of the proportional valve driving circuit 5 is on, the electrolytic capacitor 42 is charged, and when the power transistor 52 is off, the electrolytic capacitor 42 is charged. Discharges.

As described above, the electrolytic capacitor 42 (5 μF in this embodiment) repeats charging / discharging according to the pulse waveform, and the waveform of the proportional valve current flowing through the electromagnetic coil 24 is shown in FIG. 5 (b). It can be smoothed as shown.
The capacitance may be determined in the range of 0.1 μF to 100 μF according to the PWM cycle, the resistance value of the electromagnetic coil 24, etc., and the optimum range is 1 μF to 20 μF . When the switching output 321 is input (when the heating capacity is level 5 to 8), the transistor drive circuit 43 receives the low level signal 41.
0 is output to the base 413 of the transistor 41.

The fan drive circuit 303 controls the heating capacity (level 1) determined by the temperature control unit 33 during the temperature control operation.
~ A fan current is supplied to the fan motor 852 so that a fan rotation speed suitable for Level 7) can be obtained.

The housing 7 (made of metal) is provided with inlets 72 and 73 for indoor air 71 used for mixing and combustion in the upper part of the back surface, and an outlet 75 for blowing hot air 74 into the room in the lower part of the front surface. ing. Reference numeral 76 is a duct that connects the suction port 72 and the blowout port 75, and 77 is an air guide path that guides the indoor air 71 from the suction port 73 to the combustor 1 as combustion air.

The convection fan 85 includes an impeller 851 pivotally mounted in a duct 76 downstream of the combustor 1, and an impeller 85.
1 and a fan motor 852 that drives the unit 1. The temperature setter 83 is an operation unit 70 provided on the upper surface of the housing 7.
It is a tactile switch that is assembled in 1 and sets the set temperature between 16 ° C and 26 ° C. The room temperature sensor 84 is
It is a thermistor arranged in the air guide path 77 near the suction port 73.

Next, the advantages of the gas warm air heater A of this embodiment will be described. [A] The gas warm air heater A has a switching output 321 to the capacitor connection circuit 4 when the heating capacity is large (levels 5 to 8).
And a capacitor connection circuit 4 for electrically connecting the electrolytic capacitor 42 to both ends of the electromagnetic coil 24 of the proportional valve 2 by the switching output 321.

Therefore, when the on-duty of the power transistor 52 is large {heating capacity levels 5 to 8}, the waveform of the current flowing through the electromagnetic coil 24 of the proportional valve 2 is shown in FIG.
Is smoothed as shown in (b). As a result, the vibration of the plunger 23 becomes small in the strong combustion range (5th to 7th speeds), so that the sliding contact noise due to the sliding inside the sliding cylinder 203 becomes small, and the user feels uncomfortable. Do not give.

FIG. 7 is a graph in which the relationship between the heating capacity and the intensity of the sliding contact noise in the gas warm air heater A of this embodiment is measured, and as is clear from this graph (solid line in FIG. 7). The sliding contact noise of the proportional valve 2 in the strong combustion range (5th to 7th speeds) is significantly reduced as compared with the conventional product (dotted curve).
The electrolytic capacitor 42 is not electrically connected to the electromagnetic coil 24 when the heating capacity is 1st to 4th speed, but the electrolytic capacitor 42 is electrically connected to the electromagnetic coil 24 when 5th speed or higher .

[A] In the weak combustion range (1st speed to 4th speed), the capacitor connection circuit 4 does not connect the electrolytic capacitor 42 to both ends of the electromagnetic coil 24, and the microcomputer 3 causes the power transistor to pass through the transistor drive circuit 53. Since the configuration is such that the on-duty of 52 is PWM-controlled, the plunger can be vibrated reliably, and as a result, the hysteresis of the proportional valve 2 can be prevented and the combustor 1 can be burned with a predetermined combustion capacity.

In the strong combustion range (5th to 7th speeds), the capacitor connection circuit 4 connects the electrolytic capacitors 42 to both ends of the electromagnetic coil 24, but in the strong combustion range, the electromagnetic coil 24 of the proportional valve 2 is connected. Since there is a large amount of current flowing through the coil, even if a current is passed through the electromagnetic coil 24 with a smoothed waveform, the rate of change due to hysteresis is small and it does not pose a problem.
Therefore, hysteresis can be prevented in any combustion region, and the combustor 1 can be burned with a predetermined burning capacity.

In the gas warm air heater A of this embodiment, since the electrolytic capacitors 42 are not connected to both ends of the electromagnetic coil 24 in the weak combustion range (1st speed to 4th speed), the heating capacity-hysteresis shown in FIG. As shown in the graph in which the relationship of the degree of decrease in the flow rate due to is measured, it is possible to prevent the decrease in gas flow rate (due to hysteresis) due to the electrolytic capacitor 42 in the weak combustion range (first speed to fourth speed).

[C] In the strong combustion range (5th to 7th speeds), the transistor 41 becomes conductive and the electrolytic capacitors 42 are connected to both ends of the electromagnetic coil 24. Therefore, the electrolytic capacitor 42 can be switched at high speed and has excellent durability (no contact).

The present invention includes the following embodiments in addition to the above embodiments. a. The capacity of the electrolytic capacitor 42 to be connected may be switched according to the number of combustion speeds. b. The electrolytic capacitor 42 may be connected to both ends of the electromagnetic coil 24 by using a semiconductor element other than a transistor.
Also, a relay or the like may be used.

C. The gas equipment adopting the proportional valve driving device of the second aspect may be a water heater, a gas table, a drier, etc. other than the hot air heater.

[Brief description of drawings]

FIG. 1 is an external view of a gas warm air heater according to an embodiment of the present invention.

FIG. 2 is a structural explanatory view of the gas warm air heater.

FIG. 3 is a block diagram of the gas warm air heater.

FIG. 4 is an electric circuit diagram of a proportional valve drive device used in the gas hot air heater.

FIG. 5 is a waveform diagram (a) of a proportional valve current according to a conventional proportional valve driving device and a waveform diagram (b) of a proportional valve current according to the proportional valve driving device according to the present invention.

FIG. 6 is a cross-sectional view of a proportional valve used in a gas warm air heater according to an embodiment of the present invention.

FIG. 7 is a graph in which the relationship between heating capacity and sliding contact sound intensity is measured.

FIG. 8 is a graph showing the relationship between heating capacity and the degree of decrease in flow rate (due to hysteresis).

FIG. 9 is an electric circuit diagram of a conventional proportional valve driving device.

[Explanation of symbols]

A gas warm air heater (proportional valve drive device) 2 proportional valve 3 microcomputer (drive means) 4 capacitor connection circuit (capacitor connection means) 21 valve body 22 valve seat 23 plunger 24 electromagnetic coil (coil) 26 spring 27 spring 41 transistor 42 capacitor 44 diode 51 DC power source 52 power transistor (semiconductor element) 201 primary pressure chamber (gas passage) 211 one side 212 the other side 410 low level signal (switching signal) 411 emitter 412 collector 413 base 421 plus side (other end) ) 422 minus side (one end) p pulse

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-57-110882 (JP, A) JP-A-60-132182 (JP, A) Actually open 61-9681 (JP, U) Actual-open Sho 3- 2981 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) F16K 31/06-31/11 F24H 3/04

Claims (3)

(57) [Claims] 1. A proportional valve for controlling a passage amount of a fluid, a semiconductor element connected between a direct current power source and a coil of the proportional valve, and receiving a pulse described later, and a passage amount of the fluid is reduced. In the case, the on-time of the pulse to be output is shortened, and in the case of increasing it, the on-time of the pulse is lengthened to set the duty of the semiconductor element to PWM.
In a proportional valve drive device having a drive means for controlling, in the control area where the passage amount of the fluid is small, the proportional valve
Without connecting a capacitor across the coil, proportional valve driving apparatus according to claim control pass a large amount of the fluid that is provided with a capacitor connecting means for connecting said capacitor across the coil. 2. A valve body facing a valve seat formed in the gas passage,
A proportional valve having a plunger for connecting the valve body, a spring for urging the plunger, and an electromagnetic coil for exciting the plunger in accordance with the amount of energization, and a proportional valve connected between the DC power source and the electromagnetic coil. , a semiconductor element will be described later pulse is input, and shortening the oN time of the output pulse in the case of instructing the small gas flow rate, the pulse <br/> on time in the case of instructing the atmospheric gas flow rate Increase the duty of the semiconductor element to P
In a proportional valve drive device having a WM-controlled microcomputer, the solenoid of the proportional valve is used when a small gas flow rate is indicated.
Without connecting a capacitor across the coil, proportional valve actuating device, characterized in that provided a capacitor connecting means the connecting said capacitor <br/> across the electromagnetic coil when a large gas flow rate is indicated. 3. The capacitor connecting means has an emitter connected to one side of the electromagnetic coil, a transistor to which a switching signal is inputted from the microcomputer to the base when a large gas flow rate is indicated, and one end of the transistor. a capacitor connected to the other end connected to the other side of the electromagnetic coil to the collector of the transistor, the collector of the transistor - the proportional valve driving apparatus according to claim 2 constituted by a diode connected between the emitter.