JPH04269633A - Vibration-displacement detecting apparatus - Google Patents

Abstract

PURPOSE:To diagnose whether the operation of a vibration-displacement detector is normal or not without stopping the operation of industrial apparatuses such as a motor and a pump. CONSTITUTION:When a body to be measured 101 which is attached to the shaft of a motor is vibrated in the high-frequency magnetic field which is applied from a vibration-displacement detector 2, the detected signal corresponding to eddy-current loss generated in the surface of the body 101 is outputted from the detector 2. In the detected signal, the vibration component caused by a deformed part 101a appears in addition to the fundamental wave. A deformed-part-vibration and waveform fetch circuit 104 fetches only the waveform of the vibration component. A diagnosis circuit 105 diagnoses whether the vibration displacement detector 2 is normally operated or not based on the waveform.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called eddy current loss type vibration displacement detection device for detecting the amount of vibration displacement of industrial equipment such as motors and pumps by measuring changes in impedance.

0002

2. Description of the Related Art FIG. 6 is a block diagram showing the configuration of a conventional vibration displacement detection device. In this figure, a measured object 1 made of, for example, steel is connected to a shaft between a motor and a pump (not shown), and has a circular cross section as shown in FIG.

A vibration displacement detector 2 is provided at a distance d from the end face of the object to be measured 1, and its detection signal is sent to a monitoring device 4 via an amplifier 3. There is.

Next, the operation of such a conventional device will be explained. When the measured object 1 starts rotating in the direction of the arrow, the measured object 1 vibrates in the left-right direction in FIG. 6, and the value of the distance d changes periodically.

On the other hand, the vibration displacement detector 2 generates a high-frequency magnetic field due to LC resonance, and since the object to be measured 1 vibrates in this high-frequency magnetic field, eddy current loss occurs on its surface.

[0006] This eddy current loss corresponds to a change in distance d, and due to this eddy current loss, the impedance of the oscillation circuit formed by the vibration displacement detector 2 and the oscillator in the amplifier 3 changes. Therefore, the amount of vibration displacement can be expressed as a change in the oscillation voltage (which becomes an alternating current voltage).

[0007] The monitoring device 4 constantly monitors this oscillation voltage, and when it exceeds a certain level, it considers that the voltage has reached a dangerous level, issues an alarm, and stops the operation of the motor and pump. .

By the way, in order for the monitoring device 4 to accurately perform the monitoring operation as described above, it is a prerequisite that the vibration displacement detector 2 is operating normally. Therefore, it is necessary to periodically diagnose whether or not the vibration displacement detector 2 is normal, and conventional diagnosis has been carried out as follows.

That is, the vibration displacement detector 2 is removed from the installation location of the device during operation, a simulated object to be measured is set on the vibration table at another location, and the vibration displacement detector 2 is installed at a predetermined location. Diagnosis was made by conducting vibration tests.

0010

[Problems to be Solved by the Invention] As mentioned above, in order to diagnose the vibration displacement detector 2, it must be removed from the installation location, so it is necessary to temporarily stop the operation of the motor and pump. .

[0011] However, industrial equipment such as motors and pumps are normally required to continue operating for a certain period of time, and in reality, operation can only be stopped in limited cases such as during maintenance inspections. .

Therefore, even if the vibration displacement detector 2 malfunctions during operation, the discovery of this malfunction must wait until the next maintenance inspection, and until then the monitoring device 4 performs inaccurate monitoring operations. It became.

The present invention has been made in view of the above circumstances, and it is possible to diagnose a vibration displacement detector without stopping the operation of industrial equipment, thereby improving the reliability of monitoring operation for vibration displacement. It is an object of the present invention to provide a vibration displacement detection device that can perform

[0014]

[Means for Solving the Problems] As a means for solving the above-mentioned problems, the present invention provides a device that is attached to a rotating body in order to measure the amount of vibrational displacement of the rotating body, and in which a part of the object to be measured is deformed. a vibration displacement detector that applies a high-frequency magnetic field to the object to be measured and detects the amount of vibrational displacement of the rotating body based on the eddy current loss of the object to be measured; A fundamental wave extraction circuit removes vibration components caused by the deformed portion of the object to be measured and extracts only the fundamental wave from the waveform of the detection signal from the displacement detector; a monitoring device that monitors the amount of vibration displacement of the rotating body; and a deformed portion vibration waveform that extracts only a vibration component waveform caused by the deformed portion of the measured object from the waveform of the detection signal from the vibration displacement detector. The structure includes an extraction circuit and a diagnostic circuit for diagnosing whether or not the vibration displacement detector is operating normally based on the output signal waveform from the deformed portion vibration waveform extraction circuit. .

[0015]

[Operation] In the above configuration, vibration occurs in the object to be measured attached to the rotating body as it rotates, but since the object to be measured vibrates in the high frequency magnetic field applied by the vibration displacement detector, the surface of the object to be measured vibrates. Eddy currents occur.

The vibration displacement detector sends a detection signal corresponding to the amount of vibration displacement of the rotating body to the fundamental wave extraction circuit and the deformed portion vibration waveform extraction circuit based on this eddy current loss.

In this case, in addition to the fundamental wave, a vibration component caused by the deformed part of the object to be measured is added to the waveform of the detection signal, and the fundamental wave extraction circuit extracts this vibration component. Remove it so that only the fundamental wave is extracted. Then, the monitoring device monitors the amount of vibration displacement of the rotating body based on the output signal waveform from the fundamental wave extraction circuit.

On the other hand, the deformed portion vibration waveform extracting circuit extracts only the vibration component caused by the deformed portion of the object to be measured from the waveform of the detection signal from the vibration displacement detector. Then, the diagnostic circuit diagnoses whether or not the vibration displacement detector is operating normally, based on the waveform of the extracted vibration component.

[0019]

Embodiments Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 5. However, the same components as those in FIG. 6 are given the same reference numerals, and redundant explanation will be omitted.

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. In this figure, a concave deformed portion 101a is formed in a part of the object 101 to be measured. In addition, Figure 2
is a cross-sectional view of the object to be measured 101 taken along line II-II in FIG. 1. FIG. Further, a diagnostic device 102 is provided between the amplifier device 3 and the monitoring device 4. The diagnostic device 102 includes a fundamental wave extraction circuit 103, a deformed portion vibration waveform extraction circuit 104, and a diagnostic circuit 105.

Next, the operation of this embodiment configured as above will be explained. Normally, the vibration displacement detector 2 outputs L
A high frequency magnetic field is generated due to C resonance, and the object to be measured 10
Eddy current is generated on the surface of 1. If the distance d changes, this eddy current loss changes, so the impedance of the oscillation circuit consisting of the oscillator in the vibration displacement detector 2 and the amplifier 3 changes, and these changes are caused by changes in the oscillation voltage (alternating current and It appears as (becomes). Since these amounts of change have regularity, the amount of change in the distance d can be taken as the amount of change in the oscillation voltage.

The amount of change in the oscillation voltage is input to the diagnostic device 7 via the amplifier 3 and then input to the monitoring device 4 via the fundamental wave extraction circuit 103. Further, signals on the input side and output side of the fundamental wave extraction circuit 103 are inputted to the diagnostic circuit 105 through the deformed portion vibration waveform extraction circuit 104. Here, if there is a concave deformed part 101a in the vibration detection part of the measuring object 101, which is a rotating vibrating body, the distance d from the vibration displacement detector 2 changes rapidly in that part only, and the oscillation voltage also changes. Therefore, the output waveform of the amplifier 3 becomes as shown in FIG.

FIG. 3 shows an output waveform of the amplifier 3, and also a voltage waveform including a change in the gap (distance d) between the concave deformed portion 101a of the object to be measured 101 and the vibration displacement detector 2. In FIG. 3, the voltage change of the concave deformed portion 101a is the magnitude of the vibration of the object to be measured 101 (the magnitude of the distance d).
The size remains constant regardless of the This allows the waveform of a certain size to be diagnosed. The output of the amplifying device 3 is input to the fundamental wave extraction circuit 103 of the diagnostic device 102, and one of the outputs is input to the monitoring device 4 as before. FIG. 4 shows a waveform obtained by extracting only the fundamental wave from the waveform shown in FIG.

Signals from the input side (output of the amplifier 3) and the output side of the fundamental wave extraction circuit 103 are input to the deformed portion vibration waveform extraction circuit 104. The deformed portion vibration waveform extraction circuit 104 cancels the two signals and outputs a voltage corresponding to the concave deformed portion 101a of the object to be measured 101. FIG. 5 shows a waveform of the voltage change of the concave deformed portion 101a of the object to be measured 101, which is detected by canceling the waveform of FIG. 3 and the waveform of FIG. This waveform signal is input to the diagnostic circuit 105.

The diagnostic circuit 105 uses the output of the deformed portion vibration waveform extraction circuit 104 and the concave deformation of the object to be measured 101, which has been set in advance and when the vibration displacement detector 102 is normal. Voltage signal V corresponding to section 101a
s to diagnose whether or not the operation of the vibration displacement detector 2 during operation is normal. This diagnosis result is output to an alarm device, an alarm lamp, etc. in the monitoring device 4.

According to the above embodiment, the concave deformation portion 101
The vibration waveform for a is always inputted even while the object to be measured 101 is in operation, and it is possible to diagnose whether the vibration monitoring system is normal or not during actual operation. Therefore, improving machine availability,
Early detection of abnormalities in the vibration monitoring system becomes possible.

In the above embodiment, the deformed portion 101a of the object to be measured 101 is described as having a concave shape, but it goes without saying that even if the deformed portion 101a of the object to be measured 101 has a convex shape, the present invention can be similarly applied, except that the diagnostic waveform is different.

[0028]

As described above, according to the present invention, a deformed portion is formed in a part of the object to be measured, and vibration components caused by the deformed portion are contained in the detection signal waveform from the vibration displacement detector. is added, and the operation of the vibration displacement detector is diagnosed based on this vibration component waveform, so the vibration displacement detector can be diagnosed without stopping the operation of industrial equipment such as motors and pumps. This makes it possible to improve the reliability of monitoring operations for vibration displacement of these industrial devices.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1.

FIG. 3 is a waveform diagram for explaining the operation of FIG. 1;

FIG. 4 is a waveform diagram for explaining the operation of FIG. 1;

FIG. 5 is a waveform diagram for explaining the operation of FIG. 1;

FIG. 6 is a block diagram showing the configuration of a conventional example.

FIG. 7 is a cross-sectional view taken along line XII-XII in FIG. 6;

[Explanation of symbols]

2 Vibration displacement detector 4. Monitoring device 101 Object to be measured 101a Deformed part (concave part) 103 Fundamental wave extraction circuit 104 Deformed part vibration waveform extraction circuit 105 Diagnostic circuit

Claims (1)

[Claims] 1. An object to be measured that is attached to a rotating body in order to measure the amount of vibrational displacement of the rotating body, and in which a deformed part is formed in a part of the object to be measured, and a high-frequency magnetic field applied to the object to be measured. and a vibration displacement detector that detects the amount of vibration displacement of the rotating body based on the eddy current loss of the object to be measured, and a waveform of a detection signal from the vibration displacement detector to determine the deformation of the object to be measured. a fundamental wave extraction circuit that extracts only the fundamental wave by removing vibration components caused by the vibration component, and a monitoring device that monitors the amount of vibration displacement of the rotating body based on the output signal waveform from the fundamental wave extraction circuit; A deformed part vibration waveform extraction circuit extracts only the vibration component waveform caused by the deformed part of the object to be measured from the waveform of the detection signal from the vibration displacement detector, and an output signal waveform from the deformed part vibration waveform extraction circuit. a diagnostic circuit for diagnosing whether or not the vibration displacement detector is operating normally based on the vibration displacement detector.