JPH0217277A - Device for controlling opening/closing of motor-driven valve - Google Patents

Abstract

PURPOSE:To prevent tightening and carry out accurate valve opening control by slightly opening a control valve after outputting valve closing pulses and again totally closing same. CONSTITUTION:An opening/closing signal output circuit 62 for controlling the opening/closing of a control valve 4, a secondary valve opening signal output circuit 65 which outputs valve opening pulses after outputting total closing pulses to slightly open the control valve 4, and a secondary valve closing signal output circuit 66 which outputs secondary valve closing pulses having nearly equal number of pulses to the secondary valve opening pulses after outputting the secondary valve opening pulses to close the control valve in a totally closed condition, are provided in a motor driving circuit 7. Thereby, even if tightening pulses are outputted to the driving circuit 7, the effect of the tightening pulses can be prevented, nearly totally eliminating hysteresis. Hence, the locking of a valve body, etc. can be surely prevented enabling accurate control of flow rate.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an opening/closing control device for various electric valves such as an electric expansion valve provided in a refrigerant circuit, and particularly relates to measures to prevent retightening.

(Prior art) Generally, the refrigerant circuit of an air conditioner is
As disclosed in Japanese Patent No. 70578, an expansion valve is provided between the condenser and the evaporator to expand the high-pressure refrigerant and supply it to the evaporator. The expansion valve is connected to a pulse motor to form an electric expansion valve, and the refrigerant pressure discharged from the evaporator is detected by a pressure sensor, and the pulse motor is controlled by a controller to control opening and closing of the expansion valve.

Since the pulse motor reversibly rotates to a certain angle depending on the number of energizing pulses, the opening degree of the expansion valve can be accurately controlled. When controlling the pulse motor, it is necessary to set a reference position for the valve opening relative to the output of the opening/closing pulse. Therefore, the fully closed state of the expansion valve is set as the reference position. In other words, at initialization to start control, the number of pulses corresponding to the fully closed range from fully closed to fully closed is output to the pulse motor as fully closed pulses. After that, the pulse motor rotates only the magnetic field and does not rotate the rotor, so it is possible to set an accurate reference position in the fully closed state.

(Issue 8 to be solved by the invention) In the electric expansion valve described above, when the valve closing pulse is applied to the pulse motor in the fully closed state of the expansion valve, the rotor does not rotate, and when the valve opening pulse is then applied with a current, the rotor does not rotate. , the expansion valve is supposed to open accurately in accordance with the number of pulses.

However, when the valve closing pulse is energized to the pulse motor from the fully closed state of the expansion valve, the valve element is pressed further against the valve seat than the state where it is seated on the valve seat, resulting in a so-called augmentation state, and the valve element is locked. There was a problem that accurate opening/closing control could not be performed. That is, as shown in FIG. 6A, with respect to the number of valve-closing pulses PS that fully closes the expansion valve, the number of valve-opening pulses Po that opens the expansion valve from the fully closed state increases (B
and C), if the valve-closing pulse that is energized after the valve body is seated on the valve seat is an augmented pulse, as the number of augmented pulses increases, the number of valve-opening pulses Po increases, as shown in Figure 7. becomes larger, and the hysteresis becomes larger. Furthermore, as shown in FIG. 8E, as the number of supplementary pulses increases, the valve opening torque at startup increases, causing the valve body to lock as described above and becoming uncontrollable. Even so, the refrigerant flow rate differs between when the valve is closed and when the valve is opened, making it impossible to perform accurate opening/closing control, resulting in a problem that the comfort of air conditioning is poor.

The present invention has been made in view of this point, and after outputting a fully closed pulse, the control valve is slightly opened and then fully closed again, thereby preventing the increase in pressure and ensuring accurate control. The purpose is to enable valve opening control.

(Means for Solving the Problem) In order to achieve the above object, the means taken by the invention according to claim (1) are as shown in FIG. The present invention is based on an electrically operated valve comprising: and a motor (5) that is controlled by energizing pulses and opens and closes the control valve (4).

Opening/closing signal output means (1) outputs a valve opening pulse and a valve closing pulse to the drive circuit (7) of the motor (5) to rotate the motor (5) in the forward and reverse directions, and controls the opening and closing of the control valve (4).
62) is provided.

Furthermore, after outputting a full-close pulse from the open/close signal output means (62) that closes the control valve (4) to a fully closed state, a secondary valve-opening pulse is output to the motor drive circuit (7) to close the control valve (4).
4) is provided with a secondary valve opening signal output means (65) for at least slightly opening the valve.

Further, the means taken by the invention according to claim (2) is that in the invention according to claim (1), the control valve (4) is constituted by an expansion valve interposed in the refrigerant circuit (1) of the air conditioner. On the other hand, the opening/closing signal outputting means (62) is provided with a reference setting means (64) for outputting a fully closed pulse at the time of initialization and setting an opening reference position when the control valve (4) is in a fully closed state. It is configured.

Further, the secondary valve opening signal output means (65) is configured to output a secondary valve opening pulse after the standard setting means (64) outputs a fully closed pulse from the opening/closing signal output means (62).

In addition, after the secondary valve opening signal output means (65) outputs the secondary valve opening pulse, a secondary valve closing pulse having approximately the same number of pulses as the secondary valve opening pulse is output to the motor drive circuit (7). A secondary valve closing signal output means (66) for closing the control valve (4) to a fully closed state is provided.

(Function) With the above configuration, in the invention according to claims (1) and ('2J), for example, the expansion valve (4) provided in the refrigerant circuit (1)
) is controlled to open and close by rotating the motor (5) in forward and reverse directions according to the valve opening pulse and valve closing pulse of the opening/closing signal output means (62). Then, the opening/closing signal output means (62) outputs a fully closed pulse at the time of initialization, etc., and the reference setting means (64) sets a reference position.

At that time, the secondary valve opening signal output means (65) outputs a secondary valve opening pulse to slightly open the expansion valve (4), and then the secondary valve closing signal output means (66) outputs a secondary valve opening pulse to cause the expansion valve (4) to open slightly. A valve pulse is output to bring the expansion valve (4) into a fully closed state again.

(Effect of the invention) Therefore, according to the invention according to claim (1), even if the augmented pulse ΔP is output to the motor drive circuit (7), the influence of the augmented pulse ΔP can be eliminated, so that the control Valve (4)
With the valve closing pulse PS that fully closes the valve and the valve opening pulse with the same number of pulses! The Mg1l valve (4) can be opened, and hysteresis can be substantially eliminated. Therefore,
Unlike the prior art, it is possible to reliably prevent the valve body (43) from locking, etc., and also to accurately control the flow rate.

Furthermore, conventionally, as the augmented pulse ΔP increases, the valve opening pulse increases, but this increase in the valve opening pulse can be prevented. In particular, when the power is turned off and on, conventionally, initialization is performed continuously, and the fully closed pulse (P
Although all of the pulses (T10ΔP) were augmented pulses, the influence of these augmented pulses can be eliminated.

Furthermore, although the starting torque at the time of opening the valve has increased as the number of supplementary pulses increases, this starting torque can be reduced and the valve can be opened reliably.

Further, according to the invention according to claim 2, the refrigerant circuit (1)
Since the expansion valve (4) can be accurately controlled, comfortable air conditioning control can be performed.

(Example) Hereinafter, an example of the present invention will be described in detail based on the drawings.

As shown in Fig. 2, (1) is a refrigerant circuit in a separate air conditioner, in which an outdoor unit (2) and an indoor unit (3) are connected, and the cooling cycle and heating cycle are reversibly operated. configured to be possible.

The outdoor unit (2) includes a compressor (21), a four-way switching valve (22), and an outdoor heat exchanger (23) on the heat source side that functions as a condenser during the cooling cycle and as an evaporator during the heating cycle.
) and an electric expansion valve (24) which is an electric valve, and the respective devices (21) to (24) are connected to each other through a refrigerant pipe (11) so that refrigerant can freely flow therethrough. Furthermore, a temperature sensor (
25) is provided, and the temperature sensor (25) detects the suction pipe temperature.

Further, the indoor unit (3) is configured to include an indoor heat exchanger (31) on the user side that serves as an evaporator during the cooling cycle and as a condenser during the heating cycle, and the indoor heat exchanger (31) is equipped with a refrigerant. A pipe (11) is connected. and,
The outdoor unit (2) and the indoor unit (3) are connected in a closed circuit by a refrigerant pipe (11), and during the cooling cycle, the four-way switching valve (22) is switched as shown by the solid line in Figure 2 to supply the refrigerant. While the air is circulated as shown by the solid line arrow to cool and air condition the room, during the heating cycle, the four-way switching valve (2
2) is switched as shown by the broken line in Figure 2 to circulate the refrigerant as shown by the broken line arrow, thereby heating and air-conditioning the room. still,
In FIG. 2, (26) is an outdoor fan, and (32) is an indoor fan.

As shown in FIG. 3, the electric expansion valve (24) is made up of an expansion valve (4) connected to a pulse motor (5), and a valve body (41) of the expansion valve (4) has a flow path. (41a) is bored at both ends of the flow path (41a), and the refrigerant pipe (11
) is connected to the flow path (41a), while a valve seat (42
), and a valve body (43) that can be freely seated on the valve seat (42). Further, a valve shaft (44) is connected to the valve body (43), and the valve shaft (44) and the valve body (44) are connected to each other.
A bellows (45) is provided between the valve body (43) and the valve shaft (44) to maintain the valve body (43) airtightly.
At the upper end of the valve body (41) is a screw member (46) screwed into the valve body (41).
) are in contact. An output shaft (47) is connected to the screw member (46), and the output shaft (47) is connected to the motor shaft (51) of the pulse motor (5) via a gear mechanism (48). The rotation of the pulse motor (5) is decelerated by a gear mechanism (48) and converted into vertical linear motion by a screw member (46), so that the valve body (43) opens and closes. .

The pulse motor 5 is controlled by the energizing pulse output from the opening/closing control device 6, and the controller (61) of the opening/closing control device (6) receives the suction pipe temperature from the temperature sensor (25) and monitors the degree of superheating. It is configured to calculate and store the valve opening degree of the expansion valve (4) and the like.

Then, the output signal of the controller (61) is input to the opening/closing signal output circuit (62) which is the opening/closing signal output means,
A valve opening command circuit (63), which is a valve opening command means provided in the opening/closing signal output circuit (62), is configured to output a valve opening command signal or a valve closing command signal. Furthermore, the command signal of the valve opening command circuit (63) and the controller (
In response to the output signal of the opening/closing signal output circuit (62)
) outputs a predetermined number of valve opening pulses or valve closing pulses at a predetermined frequency to the drive circuit (7) of the pulse motor (5), and drives the pulse motor (5) in the forward and reverse directions to drive the expansion valve (4). ) is configured to control opening and closing, for example,
The number of pulses in the fully closed range from the fully closed state to the fully closed state of the expansion valve (4) is set to 2000 pulses, and these valve opening pulses and valve closing pulses are set at 200 pps (pulse p
er 5econd).

Further, the opening/closing signal output circuit (62) is provided with a reference position setting circuit (64) which is a reference setting means, and the reference position setting circuit (64) generates a fully closed pulse at the time of initializing the control program, for example. Taking into account errors, etc., a control signal is outputted to the motor drive circuit (7) to output a fully closed pulse of 2050 pulses, which is more than the number of pulses in the fully closed range, and when the expansion valve (4) is in the fully closed state. A reference position for opening adjustment is set.

Further, the opening/closing control device (6) includes a secondary valve opening output circuit (65) which is a secondary valve opening signal output means and a secondary valve closing signal output circuit (66) which is a secondary valve closing signal output means. It is provided. The secondary valve opening signal output circuit (65) is configured to output a secondary valve opening pulse when the opening/closing signal output circuit (62) outputs a fully closed pulse, that is,
After outputting the fully closed pulse at initialization and after outputting the fully closed pulse at the end of the operation, a secondary valve opening pulse of 150 pulses is applied to the motor drive circuit (7) to slightly open the expansion valve (4). is configured to print. The secondary valve closing signal output circuit (66) outputs a secondary valve closing pulse after the secondary valve opening signal output circuit (65) outputs the secondary valve opening pulse. The valve pulse is 150 pulses, which is the same number of pulses as the secondary valve opening pulse, and is designed to bring the expansion valve (4) into the fully closed state again.

Further, the opening/closing control device (6) is provided with a starting valve opening circuit (67) which is a starting valve opening means, and the starting valve opening circuit (67) is configured so that the opening/closing signal output circuit (62) is fully closed. After outputting the pulse, when a valve opening command signal is received from the valve opening command circuit (63) when the expansion valve (4) is in a fully closed state, the starting valve opening pulse is output at a low frequency. In other words, the starting valve opening circuit (67) has a pulse frequency (200p) that the opening/closing signal output circuit (62) outputs only when starting the valve opening.
starting valve opening pulse (e.g. 10 ps) up to a preset valve opening at a frequency lower than, e.g.
0 pulse) is output to the motor drive circuit (7).

Next, the heating and cooling operation of this air conditioner will be explained.

First, during the cooling cycle, as shown by the solid line in Figure 2, the four-way switching valve (22) is switched to circulate the refrigerant, which radiates heat through the outdoor heat exchanger (23) and transfers heat to the indoor heat exchanger (31). While heat is absorbed, during the heating cycle, the four-way switching valve (22) is switched to circulate the refrigerant, as shown by the broken line in Figure 2.
Heat is collected in the outdoor heat exchanger (23) and transferred to the indoor heat exchanger (31)
It dissipates heat and air-conditions the room.

In this refrigerant circuit (1), a temperature sensor (2
5) detects the suction pipe temperature of the compressor (21), and upon receiving the refrigerant pressure signal, the controller (6]) calculates the degree of superheat and controls the electric expansion valve (24). Therefore, the opening/closing control of the electric expansion valve (24) will be explained based on the control flow shown in FIG. 4.

First, in step ST1, when the power is turned on, the process moves to step ST2, where initialization is performed, and the open/close signal output circuit (62) outputs a fully closed pulse to the motor drive circuit (7) according to the control signal of the reference position setting circuit (64). The expansion valve (4) is fully closed by the pulse motor (5). In other words, the full-close pulse (PT + ΔP), which is the full-close pulse PT (2000 pulses) that operates the expansion valve (4) from fully closed to fully closed, plus an augmented pulse △P (50 pulses) that takes into account errors, is normally used. Frequency f2 (200p
ps).

After outputting this fully closed pulse (PT+△P), the secondary valve opening signal output circuit (65) outputs the secondary valve opening pulse PA to the motor drive circuit (7), for example, outputs 150 pulses and expands once. Open the valve (4) slightly. Subsequently, after outputting the secondary valve opening pulse PA, the secondary valve closing signal output circuit (66)
outputs a secondary valve closing pulse Pa to the motor drive circuit (7) to fully close the expansion valve (4) again. At this time, the secondary valve opening pulse PA opens the expansion valve (4) from the fully closed state, so
The normal frequency f2 is determined by the control signal of the starting valve opening circuit (67).
Output at a lower low frequency f+ (eg, 150 pps). Then, a reference position is set when the expansion valve (4) is in a fully closed state, and, for example, the step position is set to 0, and thereafter a valve opening pulse and a valve closing pulse are output.

Next, the process moves to step ST3, and it is determined whether or not there is a valve open signal.The process waits until the valve open signal is received, and if there is a valve open signal, the process moves from step ST3 to step ST4. Then, the fully closed pulse (PT+) of the open/close signal output circuit (62)
When the valve opening command circuit (63) outputs a valve opening command signal in response to ΔP), the startup valve opening circuit (67) generates a predetermined pulse Pc.
Starting valve opening pulse P up to (e.g. 100 pulses)
C is output at a low frequency f+ (150 pps) lower than the normal frequency f2 (200 pps), and the pulse motor (
5), the starting torque is increased, the starting compensation valve opening operation is performed, and the normal frequency [
At step 2, a valve opening pulse is output to the motor drive circuit (7) to open the expansion valve (4) to the set opening degree.

The process moves from step ST4 to step ST5, and the expansion valve (4) is controlled in the normal mode. That is, the controller (61) outputs a control signal so that the degree of superheat reaches a predetermined value based on the suction pipe temperature of the temperature sensor (25), and this control signal causes the valve opening command circuit (63) to open or open the valve. A valve closing command signal is output, and the opening/closing signal output circuit (62) outputs a valve opening pulse or a valve closing pulse at a normal frequency f2.

This causes the pulse motor (5) to rotate forward and reverse, causing the valve body (43
) moves up and down to adjust the expansion valve (4) to the set opening degree, and as shown in FIG. 5, the refrigerant flow rate is controlled in proportion to the number of pulses.

After that, the process moves to step ST6, and it is determined whether or not there is a fully closed signal, and the process returns to step ST5 until there is a fully closed signal. On the other hand, if there is a fully closed signal that fully closes the expansion valve (4),
The process moves from step ST6 to step ST7. When terminating heating and cooling control, etc., the controller (
When the valve opening command circuit (63) outputs a fully closed command signal via the valve opening command circuit (61), the open/close signal output circuit (62) generates a fully closed pulse obtained by adding an augmented pulse △P to the number of pulses for the current opening at the normal frequency. It outputs to the motor drive circuit (7) at f2 to fully close the expansion valve (4). After outputting this fully-closed pulse, the secondary valve-opening signal output circuit (65) and startup valve-opening circuit (67) output a secondary valve-opening pulse FA at a low frequency f1 in the same manner as in step ST2, and then , the secondary valve closing signal output circuit (66) outputs the secondary valve closing pulse ps at the normal frequency f2.
output, and after slightly opening the expansion valve (4), fully close it.

Subsequently, the process returns to step ST3, and it is determined whether or not the valve opening signal has been output. If the valve opening signal is output again, the process moves to step ST4, while if the power is cut off, etc., the opening/closing control is ended. Then, when the power is turned on again, the operations from step STI described above will be performed.

Therefore, after the opening/closing signal output circuit (62) outputs the fully closed pulse, the secondary valve opening signal output circuit (65) and the secondary valve closing signal output circuit (66) each output the expansion valve (4).
) is opened once and then fully closed again, so
Even if the augmented pulse ΔP is output to the pulse motor (5), the influence of the augmented pulse ΔP can be eliminated, and as shown in FIG. 6A, the valve closing pulse Ps that fully closes the expansion valve (4)
The expansion valve (4) can be opened with the same number of valve opening pulses as the number of pulses, and hysteresis can be substantially eliminated. Therefore, it is possible to reliably prevent the valve body (43) from locking, etc., as in the conventional case, and it is also possible to accurately control the flow rate of the refrigerant, and to perform comfortable air conditioning control.

In addition, as shown in the seventh diagram, as the augmented pulse △P increases, the valve opening pulse "τ" increases, but as shown at point D1, the increase in the valve opening pulse can be prevented. In particular, when the power supply is continuously turned on and off, initialization is performed continuously and all the fully closed pulses (PT+ΔP) are augmented pulses, but the influence of these augmented pulses can be eliminated.

Furthermore, as shown in Fig. 8E, the starting torque at the time of opening the valve increases as the number of supplementary pulses increases, but the starting torque can be reduced to within the E1 range, and moreover, the starting torque at the time of opening the valve increases. Since the starting torque is increased in circuit (67),
The valve can be opened reliably.

In this embodiment, the secondary valve opening pulse PA and the secondary valve closing pulse ps were set to 150 pulses, but the present invention is not limited to this. It suffices if (4) is the number of pulses that slightly open the valve, and 2
The next valve closing pulse PB may be any number of pulses that cause the expansion valve (4) to close.

Furthermore, in step ST5 in FIG. 4, if the augmented pulse ΔP is small, it is not necessarily necessary to energize the secondary valve opening pulse PA and the secondary valve closing pulse PB.

Further, the frequency of the secondary valve opening pulse PA may be the normal frequency f2.

Further, the electric valve of the present invention is not limited to the electric expansion valve (24), but can be applied to various control valves, and the motor may be one that is controlled by pulses.

Further, in the present invention, although it is not necessarily necessary to provide the starting valve opening circuit (67), it is desirable to provide it.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of the present invention. 2 to 8 show an embodiment of the present invention, FIG. 2 is a refrigerant circuit diagram, FIG. 3 is a longitudinal cross-sectional view of an electric expansion valve, and FIG. 4 is a control flow showing opening and closing operations of the expansion valve. It is a diagram. Figure 5 is a flow rate characteristic diagram for opening/closing pulses, Figure 6 is a flow rate characteristic diagram for opening/closing pulses in the vicinity of fully closed, Figure 7 is a diagram of changes in valve opening pulses for augmented pulses, and Figure 8 is a graph at startup for augmented pulses. FIG. 3 is a characteristic diagram of valve opening torque. (1)...refrigerant circuit, (4)...expansion valve, (5)...
...Pulse motor, (6)...Opening/closing control device, (7)
...Motor drive circuit, (24) ...Electric expansion valve, (
25) Temperature sensor, (42) Valve seat, (43
)... Valve body, (61)... Controller, (62)
...Opening/closing signal output circuit, (63)...Valve opening command circuit, (64)...Reference setting circuit, (65)...Secondary valve opening signal output circuit, (66)... Secondary valve closing signal output circuit, (67)...Start valve opening circuit. Figure ↑ (-? Open Hiro) Figure 5 Pulse number diagram

Claims (2)

[Claims] (1) A motor-operated valve comprising a control valve (4) that controls fluid, and a motor (5) that is controlled by an energization pulse and opens and closes the control valve (4), wherein the motor (5) is driven. an opening/closing signal output means (62) that outputs a valve opening pulse and a valve closing pulse to the circuit (7) to rotate the motor (5) in the forward and reverse directions to control opening and closing of the control valve (4); ) to a fully closed state after outputting a fully closed pulse from the open/close signal output means (62), a secondary valve opening pulse is output to the motor drive circuit (7) to slightly open the control valve (4). A secondary valve opening signal output means (65), and after outputting the secondary valve opening pulse of the secondary valve opening signal output means (65), a secondary valve closing pulse having approximately the same number of pulses as the secondary valve opening pulse is outputted as described above. An electric valve opening/closing control device comprising: secondary valve closing signal output means (66) for outputting to a motor drive circuit (7) to close the valve (4) to a fully closed state. (2) The control valve (4) is composed of an expansion valve installed in the refrigerant circuit (1) of the air conditioner, while the open/close signal output means (62) outputs a fully closed pulse at initialization to control the above. A reference setting means (64) is provided for setting the opening degree reference position when the valve (4) is fully closed, and a secondary valve opening signal output means (65) is configured to open/close based on the reference setting means (64). 2. The electrically operated valve opening/closing control device according to claim 1, wherein the signal output means (62) is configured to output a secondary valve opening pulse after the signal output means (62) outputs a fully closing pulse.