JPH07128131A - Detector - Google Patents

Abstract

PURPOSE:To measure an absolute vibration of an object to be measured by using an eddy-current displacement transducer by holding one side at a mounting base through an elastic element and so fixedly disposing the other at the base as to be opposed at an air gap thereto. CONSTITUTION:A coiled spring 3 fixed at one end to an inner surface of a bottom of a mounting base 2 fixed to an object 7 to be measured supports a metal 4 at its free end. Accordingly, since the vibration of the object 7 is buffered by the spring 3, it is not transmitted to the metal 4. On the contrary, the vibration of the object 7 is transmitted to an eddy-current displacement transducer 5 fixed to the base 2 and disposed oppositely to the metal 4 through an air gap through the base 2 as it is. Thus, a change of the air gap between the metal 4 and the member 5 corresponds to an absolute vibration of the object 7, and hence the absolute vibration of the object 7 can be measured based on the detection of an impedance change generated at the meter 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a detector used for measuring vibration of an object to be measured.

[0002]

2. Description of the Related Art Conventionally, when measuring vibration using an eddy current displacement gauge, the vibration was measured by installing the eddy current displacement gauge in a contactless manner facing the object to be measured. Since it may be transmitted to the mounting base, which is the installation part of the displacement gauge, even if you want to measure the absolute vibration of the measurement object, the measured value is between the eddy current displacement meter and the measurement object. It was a relative vibration of, and the absolute vibration could not be measured.

On the other hand, in the case of a detector for measuring the vibration or rotation speed of an object to be measured in a non-contact manner using magnetism, it is generally the best in terms of detection characteristics that the tip of the detector has no metal. . However, in order to protect the parts inside the detector and prevent the parts from falling off, a metal top detector using a metal at the tip has come to be used.

In this case, in order to utilize the magnetism and not lower the detection sensitivity, it is necessary to make the metal at the tip as thin as possible. For example, in the case of a vibration phase angle reference detector used in a turbine generator, the metal plate at the tip is made of stainless steel and has a thickness of about 0.1 to 0.4 mm.

When used under normal conditions, there is no problem with the above thickness, but for example, when the place of use is at high pressure, the metal plate is deformed or damaged by the pressure and cannot be used.

[0006]

In the prior art in which an eddy current type displacement gauge is attached to a mounting base so as to face the object to be measured in a non-contact manner, the absolute vibration of the object to be measured cannot be measured.
Therefore, an object of the first invention of the present application is to provide a detector capable of measuring the absolute vibration of an object to be measured using an eddy current displacement meter.

On the other hand, in a detector that uses magnetism to contactlessly measure the vibration or rotation speed of an object to be measured, the tip metal plate for protecting the inside of the detector should be as thin as possible in terms of detection characteristics. Although desirable, there is a problem that it cannot withstand use in a high-pressure environment. Therefore, an object of the second invention of the present application is to provide a detector in which the tip metal plate is sufficiently thin and has high sensitivity and which can be used even in a high pressure environment.

[0008]

SUMMARY OF THE INVENTION A detector according to the first invention of the present application comprises a hollow mounting base, a conductive body which is held inside the mounting base via an elastic body and is displaceable, and an eddy current displacement. It comprises any one of the total number and the other fixedly arranged inside the mount so as to face the one with a gap.

The detector of the second invention of the present application has a coil or a permanent magnet for generating a magnetic field in a cylindrical case made of a magnetic material, and the tip of the case is sealed with a thin metal plate for measurement. In a detector for detecting the vibration or rotation speed of an object, a liquid is enclosed in a case sealed by the metal plate.

[0010]

In the detector of the first invention of the present application, one of the conductive body and the eddy current displacement gauge is held on the mounting base via the elastic body, so that vibration from the outside is buffered and not transmitted. Since the other is fixedly arranged on the mount so as to face one with a gap, the vibration of the measurement object is transmitted as it is through the mount. Therefore, the change in the gap between the conductive object and the eddy current displacement meter corresponds to the absolute vibration (displacement) of the measurement target, and the absolute vibration of the measurement target can be measured.

In the detector of the second invention of the present application, since the liquid is enclosed in the case whose tip is sealed by the metal plate, the pressure applied to the thin metal plate is kept even when used in a high pressure environment. Since the thin metal plate is not displaced and is not subjected to bending stress because it is received by the case through, the measurement can be performed with high sensitivity without causing permanent deformation or damage.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the embodiments shown in the drawings.

FIG. 1 shows a detector according to an embodiment of the first invention of the present application. The detector 1 includes a hollow mounting base 2 fixed to an object to be measured 7 with a fixing bolt 6, a coil spring 3 having one end fixed to the inner surface of the bottom of the mounting base 2, and the coil spring. A metal body 4 which is horizontally supported on the free end of 3 and is displaceable inside the mounting base 2;
And an eddy current type displacement meter 5 fixedly arranged on the top of the mount 2 so as to face each other with a gap.

In the detector 1 of the embodiment of the first invention of the present application constructed as described above, the coil spring 3 having one end fixed to the inner surface of the bottom of the mounting base 2 fixed to the object 7 to be measured.
The metal object 4 supported on the free end of the
Is not transmitted because it is damped by the coil spring 3. On the other hand, the vibration of the measuring object 7 is transmitted as it is to the eddy current displacement gauge 5 fixedly arranged on the mounting base 2 so as to face the metal body 4 with a gap. Therefore, the change in the gap between the metal body 4 and the eddy current displacement meter 5 corresponds to the absolute vibration of the measurement target 7, and the measurement target is detected based on the detection of the impedance change generated in the eddy current displacement meter 5. The absolute vibration of the object 7 can be measured. Further, since the change in the gap with the measurement object 7 is not directly measured, the physical calibration with the measurement object is not required, and the productivity and the maintainability are greatly improved.

Next, a modification of the first invention of the present application will be described with reference to FIG. The detector 11 of this modification is obtained by replacing the metal body and the eddy current displacement meter in the embodiment of FIG. 1, and the metal body 14 is provided on the inner surface of the bottom of the mounting base 12 as shown in FIG. The eddy current displacement gauge 15 is placed and fixed, and is attached to the free end of the coil spring 13 whose one end is fixed to the inner surface of the top of the attachment base 12 and faces the metal body 14 with a gap. This modified example has the same operations and effects as the embodiment of FIG.

Next, another embodiment of the first invention of the present application will be described with reference to FIG.
Will be described. In the detector 21 of this embodiment, when the mounting base is made of metal (conductive material) in the configuration shown in FIG. 2, the desired function is achieved without installing the metal body 14 on the bottom inner surface of the mounting base. And a coil having one end fixed to the inner surface of the top of the mounting base 22 so as to face the inner surface of the bottom member of the mounting base 22 with a gap. And an eddy current type displacement meter 25 attached to the free end of the spring 23. The detector 21 of this embodiment has the same actions and effects as the embodiment of FIG.

The first invention of the present application is not limited to the above-described embodiment, but can be implemented in various modifications as described below.

(A) The elastic body is not limited to the coil spring, but may be a leaf spring, a spiral spring, rubber, sponge, an air damper, an oil damper, magnetism or the like.

(B) There is no limitation on the number of elastic bodies and the mounting direction.

(C) The number of eddy current displacement gauges installed may be plural, and vibrations from multiple directions may be measured by one detector.

(D) A guide for guiding the displacement of the conductive body or the eddy current displacement gauge held by the elastic body may be provided.

Next, the detector of the second embodiment of the present invention will be described with reference to FIG. Detector 31 shown in FIG.
Is the case where it is used as a vibration phase angle reference detector.
The detector 31 has a cylindrical case 32 made of a magnetic material, a permanent magnet 33 inside the case 32, and a coil winding frame 34 and a coil 35 concentrically attached to the outside thereof. The front end of the case 32 is sealed with a metal plate 36, and a filling liquid 37 is filled inside the case.

The metal plate 36 is made of a thin non-magnetic metal such as stainless steel in order to reduce the detection sensitivity as much as possible. In this embodiment, a stainless steel plate having a thickness of 0.2 mm is fixed to the case 32 by welding or brazing. Silicon oil is preferable as the fill liquid 37.

The detector 31 of the second embodiment of the present invention having the above-described structure is installed in a steam turbine for use as shown in FIG. 5 (a), for example. A protrusion 42 is provided on the outer peripheral surface of the shaft 41 that rotates at high speed, and the detector 31 is attached to the casing 43 so as to face the protrusion 42.

Each time the shaft 41 rotates and the projection 42 approaches and passes the tip of the detector 31, the detector tip made by the permanent magnet 33 placed inside the detector 31 The magnetic field changes, and the change occurs in the coil 35, as shown in FIG.
It is generated as a voltage as shown in (b). By detecting this voltage, the time required for the protrusion 42 to pass through can be detected in a non-contact manner.

The pressure applied to the metal plate 36, which is thinned so as not to lower the detection sensitivity, is received by the case 32 through the filled liquid 37, so that the metal plate 36 is not displaced and no bending stress is applied, so that it is permanent. It is possible to measure with high sensitivity without causing deformation or damage. The effect of protecting the metal plate 36 by the enclosed liquid 37 is particularly remarkable when the detector 31 is used in a high-pressure atmosphere such as a water supply pump.

In the above-mentioned embodiment, the case where the invention is applied to the vibration phase angle reference detector is explained. However, the detector of the second invention of the present application is the same detector using magnetism, eddy current type displacement detector. The same can be applied to a meter, an electromagnetic speed detector, and the like. For example, the one shown in FIG. 6 is an example implemented in an eddy current type displacement meter, in which a coil 55 is provided at the tip of an insulator 53 arranged in the case 52, and the tip of the case 52 is sealed and provided. The space between the thin metal plate 56 and the insulator 53 is filled with the filling liquid 57, and the same protection effect as that of the embodiment of FIG. 4 can be obtained.

[0028]

As described in detail above, according to the first invention of the present application, a hollow mounting base, a conductive body and an eddy current which are held inside the mounting base via an elastic body and are displaceable. By realizing a detector comprising any one of the displacement sensors and the other fixedly arranged inside the mounting base so as to face the one with a gap, a conductive object and Of the eddy current displacement gauges, one is held on the mounting base via an elastic body, so external vibrations are buffered and not transmitted, and the other is fixedly mounted on the mounting base so as to face one side with a gap. Therefore, the vibration of the measuring object is transmitted as it is through the mounting base. Therefore, the change in the gap between the conductive object and the eddy current displacement meter corresponds to the absolute vibration (displacement) of the measurement target,
The absolute vibration of the measuring object can be measured. Further, since the change in the gap with the measurement object is not directly measured, the actual calibration with the measurement object is not required, and the productivity and maintainability are greatly improved.

According to the second invention of the present application, a magnetic field generating coil or a permanent magnet is provided in a cylindrical case made of a magnetic material, and the case tip is sealed with a thin metal plate. In the detector that detects the vibration and the number of revolutions of the object to be measured, by realizing the detector characterized by enclosing the enclosed liquid in the case sealed by the metal plate, this detector is Even when used in an environment, the pressure applied to the thin metal plate is received by the case through the enclosed liquid, so the thin metal plate does not displace and no bending stress is applied, so permanent deformation and damage do not occur, and highly sensitive measurement is possible. it can.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing a detector according to an embodiment of the first invention of the present application.

FIG. 2 is a schematic sectional view showing a detector according to another embodiment of the first invention of the present application.

FIG. 3 is a schematic sectional view showing a detector according to another embodiment of the first invention of the present application.

FIG. 4 is a sectional view showing a detector of one embodiment of the second invention of the present application.

5 (a) and 5 (b) show an installation example and operation of the detector of FIG. 4, FIG. 5 (a) is a schematic cross-sectional view showing an installation state, and FIG. 5 (b) is an output. It is a figure which shows a waveform.

FIG. 6 is a cross-sectional view showing another embodiment of the second invention of the present application.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Detector 2 ... Mounting base 3 ... Coil spring 4 ... Metal body 5 ... Eddy current type displacement meter 7 ... Measurement object 11 ... Detector 12 ... Mounting base 13 ... Coil spring 14 ... Metal body 15 ... Eddy current type displacement Reference numeral 21 ... Detector 22 ... Mounting base 23 ... Coil spring 25 ... Eddy current displacement gauge 31 ... Detector 32 ... Case 33 ... Permanent magnet 34 ... Coil reel 35 ... Coil 36 ... Metal plate 37 ... Filled liquid 41 ... Shaft 42 ... Protrusion 43 ... Casing 52 ... Case 53 ... Insulator 55 ... Coil 56 ... Metal plate 57 ... Filled liquid

Claims (4)

[Claims] 1. A hollow mounting base, any one of a conductive body and an eddy current displacement gauge that are held inside the mounting base via an elastic body and are displaceable, and a gap between the one and the other. A detector comprising the other fixedly arranged inside the mount so as to face each other. 2. The mounting base is made of a conductive material, and an eddy current displacement gauge is held inside the mounting base via an elastic body so as to face the members of the mounting base with a gap. The detector according to claim 1. 3. The method according to claim 1, further comprising a guide for guiding the displacement of either the conductive body held by the elastic body or the eddy current displacement gauge.
The detector according to any one of 1. 4. A cylindrical case made of a magnetic material has a coil for generating a magnetic field or a permanent magnet, and a tip of the case is sealed with a thin metal plate, and the vibration or the object of measurement is measured. A detector for detecting the distance to an object, the number of revolutions of an object, etc., characterized in that an enclosure liquid is enclosed in a case sealed with the metal plate.