TECHNICAL FIELD

The present invention relates to a flow rate regulating valve and a fluid control apparatus using the same.

BACKGROUND ART

The invention described in Patent Literature 1 is a fluid pressure automatic regulating apparatus provided with a plug body and an actuator for urging the plug body.

The invention of Patent literature 1 is intended to solve problems such that too much works are required for re-adjustment and maintenance of the apparatus according to an abrasion amount of a plug body8and a plug seat9in a fully closed operation detecting mechanism of an automatic electric flow rate pressure regulating apparatus of the Patent Literature 1 as illustrated inFIG. 5, and that leakage of fluid may occur easily when fully closed due to lowering of the control accuracy. The invention disclosed in the Patent Literature 1 provides an automatic flow rate pressure regulating apparatus capable of accurately detecting a fully-closed operating state without requiring readjustment of control setting values or the like every time even when wear of the plug body8or the plug seat9is advanced, and preventing damage of a shaft7, the plug body8, the plug seat9, and the like due to leakage of fluid or excessive depression of the plug body8when fully closed.

In order to solve this problem, as shown inFIG. 1(FIG. 5Ain this application) andFIG. 2(FIG. 5Bin this application) of the Patent Literature 1, the invention described in the Patent Literature 1 solves the problem by the following operation mechanism.

First, by turning a motor1, a slider4is moved downward via a ball screw3, and a shaft presser6is also lowered in a state if being pressed downward by a constant pressing force of a spring5. Then, when the plug body8at a distal end of the shaft7comes into abutment with the plug seat9, lowering movement of the shaft presser6stops. However, since the slider4is lowered continuously, a contact between a stopper16and the shaft presser6(or a contact between the shaft presser6and a contact strip24) is disconnected, so that electric constants of control current or a control circuit change. Then, a drive control circuit of a motor is operated by the change in the control current and the electric constant, the motor is stopped, and a fluid flow path is maintained in a closed state.

Therefore, the invention described in the Patent Literature 1 has a basic configuration in which a contact between the inner peripheral surface18aof an insertion path for the stopper16and a locking surface6aof the shaft presser6is used as a detection contact when the flow path is fully closed to stop the drive motor1when the contact is opened.

CITATION LISTS

Patent Literature

Patent Literature 1: JP-B-7-058444

SUMMARY OF INVENTION

Technical Problem

In the invention described in Patent Literature 1, in order to detect the state where the flow path is fully closed, an insulating ring cylindrical body15, insulating films20,21,22, a lead wire23and a detector for capturing changes in electric constants of the control current and the control circuit must be separately prepared, which results in a cost increase. Also, there is a need for a power supply for supplying power to the detector, wires for transmitting power from the power supply to the detector, and a lead wire for extracting a detection result from the detector. Although these wires are connected to inside and outside of the valve, a space for installing the wires is required in the valve correspondingly. Further, when a plurality of the wires are attached to the valve, it is necessary to pay attention to a position or the like of wires so as not to erroneously disconnecting the wires at the time of installation or inspection of the valve, for example, and therefore, handling is troublesome.

It is an object of the present invention to provide a flow rate regulating valve capable of detecting a state where a flow path is fully closed even if there are no component such as lead wires required in the invention disclosed in Patent Literature 1 for detecting the state where the flow path is fully closed.

Solution to Problem

The present invention (1) provides a flow rate regulating valve including a valve body for opening and closing a fluid flow path formed in a body and an actuator unit for moving the valve body, in which the actuator unit includes: a drive motor; a slider moved by a rotation of the motor; a cylindrical body attached to the slider; and a shaft interlocked with the cylindrical body and fixed to the valve body at a distal end thereof, and in which the motor is a stepping servomotor, and has a pressing control function for moving the valve body in a closing direction at a continuous rated torque or below until a torque value becomes equal to or higher than a set value by a closed loop caused by a signal of the encoder, and detection of the closed position is performed by the pressing control function.

The stepping servomotor is a stepping motor equipped with an encoder, capable of performing closed loop control including rotating a rotary shaft of the motor at every certain angle by switching a current to be passed through a motor coil according to a pulse signal transmitted from a controller, feeding back a current position and speed from the encoder, and correcting an error from an operation command pulse.

Therefore, since the present invention (1) employs the stepping servomotor as a motor and has the pressing control function for moving the valve body in a direction of an opening 0% (closed position) at a continuous rated torque or below until the torque value becomes equal to or higher than a set value by the closed loop based on the signal of the encoder, detection of the closed position is achieved by the pressing control function, so that the insulating ring cylindrical body15, the insulating films20,21,22, the lead wire23, and the detector for capturing changes in control current or an electric constant of the control circuit, which are required in the Patent Literature 1, is no longer necessary.

The present invention (2) is the flow rate regulating valve according to the present invention (1), in which the slider and the cylindrical body are unitized. By unitizing the slider and the cylindrical body, the number of parts can be reduced.

The present invention (3) is the flow rate regulating valve according to the present invention (1) or (2), in which the motor further has a position control function for controlling the position by the closed loop based on the signal of the encoder, and a speed control function for controlling the rotating speed of the motor rotary shaft, and setting of the predetermined opening is performed by the position control function and the speed control function.

The present invention (4) is the flow rate regulating valve according to any one of the present inventions (1) to (3), wherein torque abnormality is determined by the torque control function when the motor is detected at the closed position and when the predetermined opening is set.

Preferably, the motor has four functions of: position control for controlling the position by the closed loop based on the signal of the encoder; speed control for controlling the rotating speed of the motor rotary shaft; pressing control for moving the valve body toward the closed position at a continuous rated torque or below until the torque value reaches a set value or higher; and torque control for controlling the torque, the detection of the closed position is performed by the pressing control function, setting of the predetermined opening is performed by the position control function and the speed control function, and when the closed position is detected and the predetermined opening is set, the torque abnormality is determined by the torque control function.

According to the torque control function, the torque abnormality is detected and alarm is issued before the flow rate regulating valve is completely failed and becomes inoperable, whereby maintenance can be performed in advance, the flow rate regulating valve can be prevented from being suddenly damaged during the process, and the process can be prevented from being seriously damaged. In this way, it is possible to prevent damage to the flow rate regulating valve due to possible overload in advance, which may be caused by converting a manually operated device into an electrically operated configuration.

The present invention (5) is a fluid control apparatus including a plurality of lines each having a flow rate regulating valve, the opening of which is set to a prescribed value, in which each of the flow rate regulating valves of the plurality of lines is the flow rate regulating valve according to any one of the present inventions (1) to (4), and the amount of operation of the motor of each of the flow rate regulating valves is monitored by a monitoring apparatus connected by a communication device.

According to this fluid control apparatus, the opening of the flow rate regulating valve in which the opening is set manually in the related art can be set by using the motor, and openings of all the flow rate regulating valves can be monitored by the monitoring apparatus, so that enhancement of the flow rate controlling function of the fluid control apparatus is achieved.

As the monitoring apparatus, a personal computer, a tablet, a smartphone, or the like may be used. The communication device may be wireless or wired, and the Internet may also be used.

In addition to torque (rotation, electric current, voltage), measuring instruments for transmitting signals such as an image (moving image), temperature, humidity, acceleration (vibration), sound and the like may be appropriately added to the flow rate regulating valve to make it possible to confirm whether or not the operation is actually performed after the operation instruction is issued from the monitoring apparatus. As the measuring instrument, a MEMS sensor, a compact CCD camera, or the like can also be used as well as various measuring instruments. Further, by providing the monitoring apparatus and the measuring apparatus with the controlling function, regulation to a target flow rate may be automatically performed.

Advantageous Effects of Invention

According to the flow rate regulating valve of the present invention, there is provided a flow rate regulating valve capable of detecting a state where a flow path is fully closed even if there are no component, wire or the like required in the invention disclosed in the Patent Literature 1 for detecting the state where the flow path is fully closed.

