JPH06337079A - Motor-controlled valve device - Google Patents

Abstract

PURPOSE:To perform a high-speed and highly accurate open/close operation, and prevent the seizure of a valve driving shaft from being caused, regarding a valve device driven with a motor. CONSTITUTION:Regarding a motor-controlled valve device where a driving shaft to open and close a valve is rotated with a motor for performing valve open/close operation, a pulse motor operable on the input of pulses is used as a motor 2. A drive means 3 for driving the pulse motor 2 and an open/close amount detection means 6 for detecting the open/close degree of a valve 1 are also provided, together with a control means 5 for controlling the drive of the motor 2, depending on the open/close degree of the valve 1 detected with the means 6. A torque detection means 7 is also provided for detecting torque acting on the driving shaft 1a of the valve 1, thereby enabling the operation of the pulse motor 2 to be stopped, when torque acting on the shaft 1a becomes equal to or greater the preset value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor control valve device, and more particularly to a motor control valve device capable of opening and closing a valve at high speed and with high accuracy.

[0002]

2. Description of the Related Art FIG. 2 is a block diagram schematically showing a configuration of a conventional motor control valve device which is opened and closed by a motor. As shown in FIG. A DC motor 22 is connected to a drive shaft 21a of a control valve 21 (for example, a needle valve) via a gearbox 24, and the drive shaft 21 is driven by the motor 22.
The degree of opening / closing of the valve 21 was adjusted and controlled by rotating a.

That is, in the DC motor 22, positive or negative power supplies 23a, 23b connected to respective contact terminals of the relay 23 via a relay 23 whose contacts are turned on and off by a current passed through a coil. The current supplied to the coil of the relay 23 is ON / OFF controlled by the controller 25 composed of a computer, a sequencer, etc., whereby the direction of the current flowing to the motor 22 is changed, The normal rotation, reverse rotation, or stop of the valve 22 is performed to open / close the valve 21 or stop the valve 21 at a predetermined position.

On the other hand, the degree of opening / closing of the flow control valve 21 is fed back to the controller 25 by a rotation sensor 26 such as a potentiometer, and the controller 25 sends a feedback signal from the rotation sensor 26 to the coil of the relay 23 as described above. The degree of opening / closing of the flow rate control valve 21 is adjusted by controlling the flowing current. Then, the series of controls is processed according to a program of a computer in the controller 25.

Further, the drive shaft 21 of the flow control valve 21
Although a limit switch 28 is provided in a, the limit switch 28 prevents the drive shaft 21a from sticking due to over-tightening of the flow control valve 21, and the drive shaft 21a rotates in the axial direction by the rotation of the motor 22. Move
When the limit switch 28 attached to the fully open or fully closed position of the flow control valve 21 is contacted, the current flowing through the relay 23 is forcibly cut off regardless of the series of control processing by the computer in the controller 25. The drive of the motor 22 is stopped.

[0006]

The conventional motor control valve device has the above-described structure.
It was not always satisfactory in terms of accuracy of opening / closing operation and operation speed. That is, it is not possible to open or close the valve by an accurate predetermined amount, and it is not possible to obtain the desired accurate flow rate, or when closing the valve, the shaft is stuck due to overtightening, It was not possible to achieve accurate opening and closing, such as complete closure, and it was also impossible to perform high-speed control.

The present inventor has researched these problems in the conventional motor control valve device and found that the cause thereof is as follows. That is, in the conventional valve device, the opening / closing speed of the valve cannot be controlled because the rotation speed of the motor 22 cannot be controlled.
5 or limit switch 28 turns relay 23 ON / O.
In the case of FF, the operation of the contact of the coil is slightly delayed from the ON / OFF timing due to the counter electromotive force of the coil in the relay 23, the motor 22 does not immediately stop due to inertia even if the contact of the coil is broken, the rotation sensor This is because there is a timing difference between the signal from 26 and the ON / OFF timing of the coil current (the reason why high speed control cannot be performed).

Further, the conventional motor control valve device has the following problems. In other words, the problem of not being able to perform the accurate opening and closing operation as described above depends on the characteristics of the individual relays and motors and the usage environment, so it is necessary to adjust the hardware and software each time it is used. It is complicated.

Furthermore, in the conventional valve device, the limit switch 28 is provided to prevent the drive shaft of the valve from sticking as described above.
In reality, it is very difficult to adjust the limit position, and there is a problem that the shaft is stuck due to a slight deviation of the limit position or complete closure cannot be achieved.

The present invention solves the above problems in the conventional motor control valve device, and an object of the present invention is to provide a motor control valve device capable of performing a high-speed and accurate opening / closing operation.

[0011]

[Means for Solving the Problems] To achieve the above object,
According to a first aspect of the present invention, in a motor control valve device that opens and closes a valve by rotating a drive shaft that opens and closes the valve by a motor, the motor is a pulse motor that is driven by pulse input. A driving means for driving the valve, an opening / closing amount detecting means for detecting the opening / closing amount of the valve, and a control means for controlling the driving of the pulse motor according to the opening / closing amount of the valve detected by the opening / closing amount detecting means. And a motor control valve device.

According to a second aspect of the present invention, in the first aspect of the invention, there is provided torque detecting means for detecting the torque of the drive shaft of the valve, and the control means has the torque detected by the torque detecting means. The present invention relates to a motor control valve device for stopping the driving of the pulse motor when the torque of the drive shaft exceeds a predetermined value.

The invention of claim 3 is the same as that of claim 1.
Alternatively, in the invention of claim 2, the control means, when the opening / closing amount of the valve detected by the opening / closing amount detecting means approaches a predetermined value, a drive pulse input from the driving means to the pulse motor. The present invention relates to a motor control valve device that reduces the frequency of the.

[0014]

In the present invention configured as described above, a control signal is output from the control means to the drive means, and a drive pulse signal based on this control signal is output from the drive means to the pulse motor. . The pulse motor is driven by the drive pulse from the drive means and rotates the drive shaft of the valve to open and close the valve.

On the other hand, a detection signal of the opening / closing amount of the valve is input to the control means from the opening / closing amount detecting means, and the control means detects the opening / closing amount of the valve at this time based on this detection signal. Then, the control means controls the opening / closing of the valve according to a predetermined program by outputting the control signal to the driving means as described above according to the detected opening / closing amount of the valve.

Since the present invention uses the pulse motor to open and close the valve as described above, the number of pulses output from the drive means to the pulse motor is controlled to control the valve drive shaft. The rotation angle can be accurately controlled. Therefore, when it is desired to open a valve by a certain amount to obtain a certain flow rate, by inputting a predetermined number of pulses to the motor, it is possible to open / close the valve much more accurately than conventional valve devices. It will be possible.

It is also possible to control the opening / closing speed by changing the frequency of the drive pulse.

Further, in the invention of claim 2, the torque of the drive shaft of the valve is detected by the torque detection means, and the detection result is input to the control means. Then, the control means stops the pulse motor when the torque of the drive shaft detected by the torque detection means exceeds a predetermined value.

Therefore, it is possible to prevent the valve shaft from sticking by presetting a value smaller than the torque value at which the valve drive shaft sticks to the control means.

Further, in the invention of claim 3, the control means controls the pulse from the driving means when the opening / closing amount of the valve detected by the opening / closing amount detecting means approaches a predetermined value. Inputting a drive pulse from the drive means to the pulse motor when the rotational speed of the motor (valve opening / closing speed) is reduced by decreasing the frequency of the drive pulse input to the motor, and then the valve has a predetermined opening / closing amount. To shut off the motor.

Thus, by reducing the operating speed of the valve (motor) before stopping it, the valve may open or close too much than a predetermined amount even when the valve is opened and closed at high speed. Therefore, more accurate opening / closing control is possible.

The pulse motor includes all motors driven by the input of a pulse signal, and also includes, for example, a motor called a stepping motor.

[0023]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram schematically showing the configuration of a motor control valve device according to an embodiment of the present invention.

As shown in the figure, a drive shaft 1a for opening and closing the flow control valve 1 is connected to a pulse motor 2 via a gear box 4, and the drive shaft 1a is rotated by the pulse motor 2. The valve 1 is opened and closed. Further, the drive shaft 1a is provided with a rotation sensor 6 for detecting the amount of rotation of the drive shaft 1a and a torque sensor 7 for detecting a load torque applied to the drive shaft 1a.

A motor power supply device 3 is connected to the pulse motor 2, and the motor power supply device 3 outputs a drive pulse to the pulse motor 2 based on a control signal from the controller 5 to drive the pulse motor 2. To do.

The controller 5 is composed of a personal computer (hereinafter, simply referred to as "computer") and a programmable controller, and the computer stores an application program for controlling the entire valve device. . On the other hand, the programmable controller serves as an interface between the rotation sensor 6, the torque sensor 7, the motor power supply device 3, and the computer.

The operation of the valve device according to this embodiment constructed as described above will be described. First, in order to set the flow rate control valve 1 to a desired opening degree (for example, 50% of full opening), the following control is performed.

That is, the computer in the controller 5 takes in the detection signal from the rotation sensor 6 via the programmable controller, and the detection signal is
It is digitized by the programmable controller and input to the computer. From this detection signal, the computer recognizes the degree of opening / closing (opening / closing amount) of the flow rate control valve 1 at the present time, and calculates in what direction and by how much the pulse motor 2 should be rotated.

The calculation result is output to the programmable controller, and the controller outputs the necessary number of voltage pulse signals to the motor power supply device 3 based on the signal. The motor power supply device 3 amplifies the voltage pulse signal and outputs a drive pulse having the same frequency to the pulse motor 2, whereby the pulse motor 2 is driven and the valve 1 is opened and closed.

On the other hand, even while the valve 1 is being driven, the rotation sensor 6 and the torque sensor 7 are constantly operated.
Detection signal is input to the programmable controller in the controller 5 from the above, the detection signal is digitized by the programmable controller and input to the computer, and the computer is momentarily based on the detection signal from the rotation sensor 6 at that time. The opening / closing amount of the valve 1 is calculated.

When the opening / closing amount of the flow control valve 1 approaches the target opening (for example, 50% of full open), the computer sets the frequency of the pulse signal to be sent to the motor power supply device 3 to the programmable controller. Command to decrease. As a result, the frequency of the voltage pulse output from the programmable controller to the power supply device 3,
Further, the frequency of the drive pulse output from the power supply device 3 to the pulse motor 2 is reduced, and the rotation speed of the pulse motor 2 is reduced.

When the opening / closing amount of the flow control valve 1 reaches the target opening (50% of full opening), the computer stops the pulse signal to be sent to the motor power supply device 3 to the programmable controller. To the motor power supply device 3 from the programmable controller.
The sending of the pulse signal to is stopped. As a result, the transmission of the drive pulse from the power supply device 3 to the motor 2 is stopped,
The motor 2, that is, the valve 1 is stopped.

The valve 1 is controlled to the target opening by the above-described control processing. However, if the valve 1 is too far over the target opening for some reason, the following control is performed.

That is, the computer in the controller 5 controls the valve 1 based on the detection signal from the rotation sensor 6.
When it recognizes that the value has exceeded the target opening, the programmable controller is immediately instructed to stop the rotation of the motor 2. Then, it calculates how much to rotate in the opposite direction to reach the target opening, and outputs a command based on the calculation result to the programmable controller. As a result, the valve 1 is returned by the amount that has exceeded the target opening, and the target opening is reached.

Next, when the flow control valve 1 is closed, the following control processing is performed.

The computer in the controller 5 receives the detection signal from the rotation sensor 6 via the programmable controller in the same manner as the above-mentioned opening / closing control of the valve to the target opening degree, and the opening / closing amount of the flow control valve 1 at the present time. Is calculated, and how much the drive shaft 1a should be rotated to close the valve 1 is calculated.

Then, based on the calculation result, the computer outputs a command signal to the programmable controller, and the programmable controller outputs the necessary number of voltage pulse signals to the motor power supply device 3, and outputs the voltage pulse signals to this voltage pulse signal. Based on the drive pulse based on the pulse motor 2
Is driven.

When the closed position is approached, the rotation speed is reduced to continue the rotation of the motor 2 as in the opening / closing control to the target opening.

On the other hand, the computer monitors the torque of the drive shaft 1a by the detection signal input from the torque sensor 7 via the programmable controller and stores the torque value measured when the flow control valve 1 is closed in advance. The stored torque value is compared with the torque value of the drive shaft 1a, and when the torque of the drive shaft 1a reaches the prestored torque value, a rotation stop command is sent to the programmable controller. Then, the pulse motor 2 is stopped.

As described above, in the present valve device, since the valve 1 is closed while monitoring the torque of the valve drive shaft 1a, the valve drive shaft 1a is reliably prevented from sticking.

Further, the drive shaft 1a of the valve is provided with a torque limiter 8. However, when the torque monitoring function of the torque sensor 7 fails, excessive torque is applied to the drive shaft 1a. This is to prevent the device from being damaged, and when a torque larger than a predetermined value is applied to the drive shaft 1a, the torque limiter 8 prevents the rotation of the pulse motor 2 from being transmitted to the flow control valve 1.

The torque limiter 8 is provided in order to enhance the safety of the apparatus, and the means is not essential to the present invention, and another mechanism for preventing excessive torque may be provided. it can.

The positions where the torque sensor 7 and the torque limiter 8 are arranged are not limited to those shown in FIG. 1, but depending on the intended use of the valve, for example, between the gearbox 4 and the flow control valve 1. Of course, it may be inserted into

[0044]

As described above, according to the present invention,
It is possible to realize a high-speed and highly accurate opening / closing operation of the valve, and it is possible to reliably prevent the drive shaft of the valve from sticking.

[Brief description of drawings]

FIG. 1 is a block diagram schematically showing a configuration of a motor control valve device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a conventional motor control valve device.

[Explanation of symbols]

1 Flow Control Valve 1a Flow Control Valve Drive Shaft 2 Pulse Motor 3 Motor Power Supply 4 Gear Box 5 Controller (Personal Computer, Programmable Controller) 6 Rotation Sensor 7 Torque Sensor 8 Torque Limiter

Claims (3)

[Claims] 1. A motor control valve device for opening and closing a valve by rotating a drive shaft for opening and closing the valve by a motor, wherein the motor is a pulse motor driven by pulse input, and a drive for driving the pulse motor. Means, an opening / closing amount detecting means for detecting the opening / closing amount of the valve, and a control means for controlling the drive of the pulse motor according to the opening / closing amount of the valve detected by the opening / closing amount detecting means. apparatus. 2. A torque detecting means for detecting a torque of a drive shaft of the valve, wherein the control means has a torque of the drive shaft detected by the torque detecting means is equal to or more than a predetermined value. The motor control valve device according to claim 1, wherein the driving of the pulse motor is stopped. 3. The control means controls the drive pulse input from the drive means to the pulse motor when the opening / closing amount of the valve detected by the opening / closing amount detecting means approaches a predetermined value. The motor control valve device according to claim 1 or 2, which reduces a frequency.