JP2003074743A - Fluid interrupting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluid interrupting device having a valve element position detecting mechanism for positively detecting the present position of a valve element by a simple low-cost mechanism and parts in the fluid interrupting device for a motor-driven valve. SOLUTION: In this fluid interrupting device for opening/closing a passage 10 formed in a device casing 1, by the valve element 4 driven by a motor 3, the valve element position detecting mechanism 5 is composed of a magnetic substance 50 interlocked with the valve element 4; a coil 52 disposed in an outside position of the passage 10 and changed in inductance by the far and near distance of the magnetic substance 50; and an inductance detecting means 53 for detecting the inductance of the coil 52. The position of the valve element 4 is detected by the difference of the inductance.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid shutoff device for a gas fluid, and more particularly to a fluid shutoff device having a valve body position detecting mechanism operated by a motor drive. 2. Description of the Related Art In a conventional fluid shut-off device, a main flow path is formed in an apparatus housing, a valve seat is disposed in the main flow path, and a valve operated by driving a motor installed in the apparatus housing. The body was brought into contact with the valve seat to shut off the flow path. And
It is important for a fluid shut-off device that handles dangerous fluids such as gas to reliably grasp the open / closed state of the flow path, and therefore it is necessary to appropriately detect the position of the valve element. A fluid shut-off device having such a valve body position detecting means is disclosed in Japanese Patent Application Laid-Open No. 2001-14109 as a conventional example.
6 was disclosed. As shown in FIG. 4A, this device has a magnetic sensor in which a plurality of magnets m are arranged in the rotation axis direction of a rotor R in a motor M, and which is installed outside via a housing partition of the motor M. S constitutes a detecting means. By detecting the number of rotations and the rotational position of the motor M by this detecting means, the valve body V
It is to grasp the position of. [0004] Japanese Patent Application Laid-Open No. 2001-141094 discloses the same one as described above. This device is shown in FIG. 4 (B), but in the same manner as described above, in addition to the magnet m of the rotor R and the magnetic sensor S installed outside the housing of the motor M, the magnet m is arranged on the valve body V. At the same time, at least two magnetic sensors S are provided on the outer surface of the device housing B along the moving direction of the valve body V.
The current position of the valve body V is detected by sensing the proximity of the valve body V to the magnet m. [0005] However, the fluid shut-off device disclosed in Japanese Patent Application Laid-Open No. 2001-141096 requires a special-purpose motor in which a magnet is arranged in a rotor, and
Since a separate magnetic sensor is required, not only the number of parts increases, but also the parts are relatively expensive, so that there is a problem that the fluid shut-off device itself becomes expensive. [0006] Further, in the above-described detection method in which the position of the valve element is grasped from the number of rotations and the rotational position of the motor, if the valve element is not operating due to a failure in the connection between the motor and the valve element, the current state of the art is not improved. The position of the valve body could not be accurately grasped, and the position of the valve body could not be corrected. Further, the fluid shut-off device disclosed in Japanese Patent Application Laid-Open No. 2001-141094 grasps the current position of the valve body from the detection of the magnet attached to the valve body by the magnetic sensor, so that even when the motor rotation is stopped. Although the position of the valve element can be grasped, the fact that the manufacturing cost and the component cost are high is not solved by separately attaching the magnet to the valve element and using a relatively expensive magnetic sensor. Further, a magnet for sensing a magnetic sensor is
Since it is arranged directly on the valve element in the flow path, fine magnetic dust remaining in the fluid conduit may adhere to the magnet after long-term use. Also, there were concerns that reliability of operation accuracy would be hindered. SUMMARY OF THE INVENTION The present invention has been made in view of such a problem, and in a fluid shut-off device for a motor-driven valve, the position of a valve body in a current state can be reliably determined by a simple and low-cost mechanism and parts. To provide a fluid shut-off device having a valve body position detecting mechanism for detecting a fluid. [0010] In order to achieve the above object, the fluid shut-off device of the present invention is configured as follows. That is, in a fluid shut-off device that opens and closes a flow path (10) formed in an apparatus housing (1) by a valve (4) driven by a motor (3), a magnetic body interlocked with the valve (4). (50), a coil (52) whose inductance changes depending on the distance between the magnetic body (50) and the outside of the flow path (10), and inductance detection for detecting the inductance of the coil (52). Means (53), and a valve element position detecting mechanism (5) comprising the means (53). Incidentally, the reference numerals in parentheses described in the claims and the section of the means for solving the problems are those attached with reference numerals in the drawings for easy understanding of the structure of the invention. Of course, it is not limited to the form on the drawing. With the above arrangement, the present invention operates as follows. By adopting the configuration of the first aspect, the magnitude of the inductance of the coil, which changes due to the influence of the magnetic material interlocking with the valve body, is detected, and the position of the valve body can be grasped. The inductance of the coil increases when the magnetic body approaches the coil, and decreases when the magnetic body moves away from the coil. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of a fluid shut-off device according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a partially cutaway perspective view showing a fluid cutoff device of the present embodiment, FIG. 2 is a cross-sectional view showing an open state of a valve body in the fluid cutoff device of the present embodiment, and FIG. It is sectional drawing which shows the closing state of the valve body in the fluid shut-off device of FIG. The fluid shut-off device A of the present embodiment is mounted on the device housing 1 to open and close the flow of gas (arrow a), and mainly includes the mounting plate 2, the motor 3, the valve body 4, and the valve position. It comprises a detection mechanism 5 and control means. The apparatus housing 1 has a flow path 10 formed therein, and the flow path 10 is connected to an inflow path 10 connected to a gas supply source.
a, an operating chamber 10b in which the valve element 4 is stored, and an outflow passage 10c connected to a gas supply destination. Further, a valve seat 13 having an annular convex portion that is in contact with the valve body 4 is formed at a boundary between the outflow passage 10c and the working chamber 10b. A mounting plate 2 serving as a support plate for the motor 3 is air-tightly joined to an opening 11 of the working chamber 10 b via an O-ring 12. The motor 3 fixed to the mounting plate 2 is appropriately selected from existing motors, and is preferably a pulse response stepping motor, but is not limited thereto. An output shaft 30 of the motor 3 extends through the mounting plate 2 into the working chamber 10b, and is connected to the output shaft 30 through a conversion means 31 for converting rotation into direct motion. Body 4 is attached. The valve body 4 is composed of a valve body holder 41 and a valve rubber 42. The valve rubber 42 disposed below is brought into close contact with the valve seat 13 by the direct movement of the valve body holder 41 driven by the motor 3. It is configured to Further, a spring 40 having an extended urging force is attached between the valve seat 13 and the opposing surface of the mounting plate 2 so that a sufficient pressing force of the valve body 4 against the valve seat 13 is secured. Has been. The above-described spring 40 has a function of removing backlash between the motor 3 and the conversion means 31, but may be omitted. Next, the valve position detecting mechanism 5, which is the main feature of the present invention, mainly comprises a coil 52, a magnetic body 50, and inductance detecting means 53. The coil 52 is formed by tightly winding a copper wire in an annular shape, and has the mounting plate 2 mounted and fixed on a cylindrical projection 20 projecting toward the non-operating chamber 10b. The magnetic body 50 is formed of, for example, a high magnetic material such as iron, and has an upper shape close to the inner peripheral surface side of the cylindrical convex portion 20 and a lower shape as shown in the drawing. Is a cylinder. The magnetic body 50 is attached to an end of a plate-shaped bracket 51 attached in a direction orthogonal to the moving direction of the valve body 4 so as to face the cylindrical convex portion 20. The magnetic body 50 is arranged on the axis of the cylindrical projection 20, and when the valve 4 is opened in conjunction with the valve 4, its tip enters the inner space of the cylindrical projection 20. Is set to The inductance detecting means 53 includes a coil 5
This is an electric circuit for detecting a change or difference in inductance from the position 2 as an electric signal, thereby detecting the current position of the valve body 4. The electric circuit for detecting the inductance uses an existing technology, for example,
A method is used in which a constant AC voltage is applied to the coil 52 and a change in current caused by the distance of the magnetic body 50 to and from the coil 52 is detected. The inductance detecting means 53 may be installed on the upper surface of the mounting plate 2 via a harness 53a as shown in the figure, but may be installed together with a control means (not shown) of the fluid shutoff device A separately provided. You may do it. The control means performs feedback control for adjusting the drive output to the motor 3 based on the information obtained by the inductance detection means 53 and correcting the position of the valve element 4. For example, when it is determined from the detection information of the inductance detecting means 53 that there is a possibility that the valve body 4 does not completely adhere to the valve seat 13, the motor 3 is started again at a high torque and the reclosing operation is performed. You may make it perform. Next, the fluid shut-off device A of the present embodiment configured as described above operates as follows. When the flow path 10 is opened (opened), the fluid flows in the direction indicated by the arrow a.
It flows in the direction of. When the flow path 10 is to be closed (cut off), the inductance detecting means 53 detects the current position of the valve element 4 from the magnitude of the inductance of the coil 52, and calculates the distance of the valve element 4 to the valve element 13 based on the information. Then, the motor 3 is commanded by the number of rotations. When the motor 3 is driven, the valve body 4 moves to the valve seat 13 side and comes into contact with the valve seat 13 (arrow b). Next, the control means detects whether the valve element 4 is actually in contact with the valve seat 13 or not, based on the inductance of the coil 52. If the position of the valve element 4 is still higher, The proper rotation speed is again commanded to the motor 3. By repeating the above, the flow path 10 is reliably shut off. The inductance of the coil 52 increases when the magnetic body 50 approaches the coil 52 and decreases when the magnetic body 50 moves away from the coil 52. However, the correlation between this value and the rotation speed of the motor 3 or the moving distance of the valve body 4 is obtained. Must be adjusted in advance. When the flow path 10 is to be opened (opened), the motor 3 is inverted and the valve 4
May be moved to the opposite side of the valve seat 13. According to the present invention, in the fluid shutoff device, since the valve position detecting mechanism for detecting the position of the valve element is configured as described above, it is possible to appropriately detect the current position of the valve element. The device can be constructed with simple and low-cost mechanisms and components while being possible. Further, since the shape and size of the magnetic material and the number of turns of the coil can be appropriately changed, the detection accuracy can be adjusted freely according to the specifications.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partially cutaway perspective view showing a fluid shut-off device of the present embodiment. FIG. 2 is a cross-sectional view showing an opened state of a valve body in the fluid shut-off device of the present embodiment. FIG. 3 is a cross-sectional view showing a closed state of a valve body in the fluid cutoff device of the present embodiment. FIG. 4 is a sectional view showing a conventional fluid shut-off device. [Description of Signs] A Fluid cutoff device 1 Device housing 10 Flow path 10a Inflow path 10b Working chamber 10c Outflow path 11 Opening 12 O-ring 13 Valve seat 2 Mounting plate 20 Cylindrical projection 3 Motor 30 Output shaft 31 Conversion means 4 Valve body 40 Spring 41 Valve body holder 42 Valve rubber 5 Valve position detection mechanism 50 Magnetic body 51 Bracket 52 Coil 53 Inductance detection means 53a Harness (for inductance detection means) B Valve housing M Motor R Rotor m Magnet S Magnetic sensor V Valve body (conventional example)

   ────────────────────────────────────────────────── ─── Continuation of front page    (72) Inventor Atsushi Noma             Microphone off the coast of Sasagino, Fukushima City, Fukushima Prefecture             B Giken Co., Ltd. F term (reference) 3H062 AA02 AA12 BB30 CC01 DD03                       EE06 FF02 FF13 HH02                 3H065 AA01 BA01 BA07 BB11 BB13                       CA01

Claims (1)

Claims: 1. A flow path (1) formed in an apparatus housing (1).
A) a magnetic body (50) moving in conjunction with the valve body (4); and a perspective view of the magnetic body (50). And the coil (5) disposed outside the flow path (10)
2) and an inductance detecting means (53) for detecting the inductance of the coil (52); and a valve element position detecting mechanism (5) comprising: