JPH07333051A - Non-contact vibration detector - Google Patents

Abstract

(57) [Summary] [Structure] A magnetic field generator such as a magnet 2 is provided on a subject 1, and a magnetic measurement device 4 and a mechanical vibration measurement which are fixed to a pedestal 7 facing the non-contact and installed in a non-contact manner. The device 6 is provided, and the signal representing the relative displacement between the subject 1 and the gantry 7 measured by the magnetic measuring device 4 is corrected by the signal representing the displacement of the gantry 7 measured by the mechanical vibration measuring device 6. As a result, a contacted vibration detection device that measures the displacement of the subject 1. [Effect] The vibration of the subject can be measured accurately and inexpensively without contact.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for measuring the amount of vibration of any mechanically vibrating object or magnet.
The present invention relates to a highly accurate and inexpensive device that can measure the vibration amount in a non-contact manner with the subject or the magnet.

[0002]

2. Description of the Related Art Generally, when detecting a vibration of a subject, a detector such as an accelerometer or a strain gauge is attached to a portion where the vibration of the subject is desired to be measured, and the measured electric signal is converted into a displacement. However, if you want to measure vibration by touching the subject, such as when the subject is cooled to extremely low temperature with liquid nitrogen or liquid helium, or when it is hot, or when it is not possible to attach the detector to the surface. In that case, an expensive and large-scale measuring device such as a laser interferometer was required. When the subject is a magnet such as a superconducting magnet, a normal conducting magnet, or a permanent magnet, a magnetic detector is provided facing the magnet as described in Japanese Patent Application No. 5-236573. It was possible to measure the amount of vibration in a non-contact manner relatively inexpensively by utilizing the change in the magnetic detector signal due to the vibration. FIG. 2 shows a conceptual diagram of the non-contact vibration measuring device according to this conventional technique. In this figure, 14 is a magnet which is an object to be oscillated, 15 is a current source for supplying a current to the magnet 14 to generate a magnetic field, 3 is a magnetic probe, 4 is a magnetic measuring device for processing signals of the magnetic probe 3, Reference numeral 7 is a mount for fixing the magnetic probe 3. In this figure, when the magnet 14 vibrates, the magnetic flux linking the magnetic probe 3 changes, and a voltage corresponding to the amount of change in the magnetic flux is generated. The magnetic measuring device 4 measures this voltage,
Finally, the original vibration amount is converted and output from this voltage value. In such a contact-type vibration measuring apparatus according to the related art, only the magnet 14 is targeted as the subject, and any general subject cannot be handled, and the signal measured by the magnetic probe 3 is relative to the magnet 14 and the pedestal 7. This is the amount of displacement, and when the gantry 7 vibrates, there was a problem that the amount of vibration of the magnet 14, which is the subject, could not be calculated accurately.

[0003]

The object of the present invention is to solve the problems of the two prior arts, that is, it is possible to target any object not limited to a magnet, and it is highly accurate, inexpensive and non-contact. It is to provide a vibration detection device.

[0004]

Means for Solving the Problems The first problem, namely, the problem of targeting an arbitrary object not limited to a magnet, is to fix a magnetic field generating means such as an electromagnet or a permanent magnet to the object. It can be solved by The second problem, that is, the problem of accurately calculating the amount of vibration of the subject, is to fix the vibration detection means in addition to the magnetic detection means on the same frame facing the subject in a non-contact manner, The problem can be solved by providing the detecting means and the means for processing the signal from the vibration detecting means.

[0005]

When a magnetic field generating means such as an electromagnet or a permanent magnet is fixed to a site where vibration of the object is to be measured, the magnetic flux generated by the magnetic field generating means is a magnetic field which is installed on a pedestal facing the object in a non-contact manner. Interlinks with magnetic detectors such as probes and Hall elements. When the subject vibrates in this state,
Since the magnetic field generating means is fixed to the subject, it causes the same vibration as the subject. As a result, the magnetic flux interlinking with the magnetic detector fluctuates in proportion to the vibration of the subject when the gantry is stationary. The magnetic detector produces a voltage proportional to this fluctuating magnetic flux, which is detected by a magnetic measuring device electrically connected thereto. However, since the pedestal also generally vibrates, the magnetic flux linked to the magnetic detector also fluctuates due to this vibration. Therefore, the voltage detected by the magnetic measurement device is proportional to the relative displacement between the subject and the gantry. Therefore, in order to accurately extract only the vibration of the subject, the vibration detector is fixed on the pedestal in addition to the magnetic detector. This vibration detector is composed of, for example, an acceleration sensor or a strain gauge, and generates a voltage proportional to the vibration of the pedestal to which it is fixed and is detected by the mechanical vibration measuring device. Finally, a signal processing means is provided to compare and calculate the voltage of the magnetic measuring device proportional to the relative displacement between the subject and the gantry and the voltage of the mechanical vibration measuring device proportional to the vibration of the gantry, Only the vibration can be taken out, and highly accurate non-contact vibration measurement can be realized as compared with the conventional technique.

[0006]

FIG. 1 shows an embodiment of the present invention. In the figure, 1 is an object whose vibration is to be measured, 2 is a magnet such as an electromagnet or a permanent magnet, 3 is a magnetic probe, 4 is a magnetic measuring device, 5 is an accelerometer, 6 is a mechanical vibration measuring device, and 7 is a pedestal. is there. The states of the voltages measured by the magnetic measuring device 4 and the mechanical vibration measuring device 6 will be described with reference to FIGS. 7 and 8. In these figures, 16 is a magnetic force line created by the magnet 2, 17 is an arrow representing the vibration of the subject 1, 18 is a voltage waveform of the magnetic probe 3, 19 is a voltage waveform of the accelerometer, and 20 is an arrow representing the vibration of the gantry 7. , 21 is the voltage waveform of the magnetic probe 3, and 22 is the voltage waveform of the accelerometer. First, FIG. 7 shows a state in which only the subject 1 vibrates and the gantry 7 stands still as indicated by an arrow 17. Due to the vibration 17, the magnet 2 also moves together with the subject 1, and the magnetic force lines 16 created by the magnet 2 also move. As a result, magnetic field lines 16 move in and out across the magnetic probe,
The voltage waveform 18 is measured. However, since the gantry 7 is stationary, nothing appears in the voltage waveform 19 of the accelerometer 5. Next, FIG. 8 shows a state in which only the gantry 7 vibrates as shown by an arrow 20, and the subject 1 stands still. The vibration 20 also causes the lines of magnetic force 16 to move in and out across the magnetic probe 3, so that a voltage waveform 21 similar to the voltage waveform 18 is measured. Further, since the accelerometer vibrates together with the pedestal 7, it outputs the voltage waveform 22. Here voltage waveform 2
Since 1 and 22 are generated by the vibration of the same gantry 7, there is a one-to-one relationship between the respective wave heights and phases. That is, from the voltage waveform 22 of the accelerometer,
It is possible to predict the voltage waveform 21 of the magnetic probe due to the vibration of As described above, in FIG. 1 which is an embodiment of the present invention, when the subject 1 and the pedestal 7 vibrate simultaneously, first, using the result of the mechanical vibration measurement device 6, the magnetic measurement device 4 based on the vibration of the pedestal 7 is used. By predicting the measurement result and then subtracting this predicted value from the measurement result of the magnetic measurement device 4, the vibration amount of only the subject 1 can be calculated. As described above, according to the present embodiment, not only the vibration of an arbitrary object can be measured in a non-contact manner, but also the local vibration and the local vibration can be suppressed by adjusting the sizes of the magnet 2 and the facing magnetic probe.
It is also possible to selectively detect only the special vibration component.
Also, instead of the magnetic probe 3, the same effect can be obtained by using other magnetic detection means such as a Hall element. further,
The same effect can be obtained by using other vibration detecting means such as a strain gauge instead of the accelerometer 5.

Another embodiment of the present invention is shown in FIG. Although the subject 1 is not shown in this figure, the configurations of the subject, the detector and the like are the same as those in FIG. 1, and a measurement data processing means is added. In this figure, 8 is data, 9 is a data conversion device, 10 is a comparison calculator, 11 is data, 12 is a data conversion device, and 13 is a display device. The data 8 stores data in which the signal of the magnetic measurement device 4 and the signal of the mechanical vibration measurement device 6, which are detected by the vibration of only the gantry 7, are associated with each other in a one-to-one correspondence. This data can be easily obtained by comparing the two voltage waveforms 21 and 22 of FIG. The data 11 is data indicating the relationship between the signal of the magnetic measurement device 4 and the displacement of the subject 1 when only the subject 1 vibrates. These data 8 and 11 can be easily evaluated by experiments and calculations as shown in FIGS. 7 and 8. The operation of this embodiment will be described. First, the signal of the mechanical vibration measuring device 6 is sent to the data conversion device 9,
By referring to the data 8, the equivalent magnetic measuring device signal is replaced. Next, this signal is output to the comparison calculator 1
0, and the signal corresponding to only the vibration component of the subject 1 is output by comparing with the signal of the magnetic measurement device 4.
This signal is converted by the data converter 12 into a signal representing the amount of vibration by referring to the data 11, and finally displayed or recorded on the display device 13. The above signal processing may be performed by an analog or digital circuit,
It may be performed programmatically using a computer. As described above, according to this embodiment, the vibration amount of the subject 1 can be automatically measured in a non-contact manner.

Another embodiment of the present invention is shown in FIG. In this figure, 14 is a magnet, 15 is a current source, and other parts are the same as in FIG. In this case, the magnet 14 is a superconducting or normal conducting magnet that generates a magnetic field by passing an electric current through the coil, and a current source 15 for that is added. In the configuration of this embodiment, the subject is the magnet 14 itself. Therefore, according to the present embodiment, it is not necessary to bother to provide the magnet 2 required for the general subject 1 as shown in FIG. 1 by utilizing the fact that the subject generates a magnetic field.

Another embodiment of the present invention is shown in FIG. The present embodiment is characterized in that a plurality of magnets 2, a magnetic probe 3, and an accelerometer 5 are installed as compared with the embodiment of FIG. Thereby, the vibration of the subject 1 corresponding to the position of each magnet 2 can be measured, and thus the detailed vibration distribution, vibration mode, etc. can be measured in a non-contact manner.

A final embodiment of the invention is shown in FIG. The present embodiment is characterized in that a plurality of magnetic probes 3 and accelerometers 5 are installed as compared with the embodiment of FIG. As described above, by installing the plurality of magnetic probes 3 and the accelerometer 5 on the magnet 14 that is one subject, the vibration corresponding to each measurement position is measured with a simple configuration, and the detailed vibration distribution, The vibration mode etc. can be measured without contact.

[0011]

According to the present invention, the vibration of an arbitrary general subject can be measured in a non-contact and accurate manner. Also,
As the magnetic field generating means, magnetic field measuring means, and vibration measuring means used for that purpose, generally used ones can be used, and therefore inexpensive and highly reliable measurement can be performed.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a non-contact vibration detection device for an arbitrary subject, showing an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a conventional non-contact vibration detection device.

FIG. 3 is a block diagram of a non-contact vibration detection device for an arbitrary subject having a measurement signal processing unit according to an embodiment of the present invention.

FIG. 4 is a block diagram of a non-contact vibration detection device using a magnet as an object according to an embodiment of the present invention.

FIG. 5 is an explanatory diagram of a non-contact vibration detection device for an arbitrary subject, which is provided with a plurality of detection means according to an embodiment of the present invention.

FIG. 6 is an explanatory diagram of a non-contact vibration detection device that uses a magnet as a subject and that includes a plurality of detection means according to an embodiment of the present invention.

FIG. 7 is an explanatory diagram of a measurement signal at the time of subject vibration according to the present invention.

FIG. 8 is an explanatory diagram of a measurement signal during vibration of the gantry of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Subject, 2 ... Magnet, 3 ... Magnetic probe, 4 ... Magnetic measuring device, 5 ... Accelerometer, 6 ... Mechanical vibration measuring device, 7 ... Stand.

Claims (7)

[Claims] 1. A magnetic field generating means fixed to a subject, a magnetic detecting means and a vibration detecting means which are fixed to the subject in a non-contact manner and fixed to the same frame, the magnetic detecting means and the vibration detecting means. Signal processing means from the magnetic detection means, the signal processing means calculates the relative displacement between the subject and the pedestal from the signal of the magnetic detection means, the absolute displacement of the pedestal from the signal of the vibration detection means. A non-contact vibration detecting device, characterized in that the absolute displacement of the subject is calculated, and the absolute displacement of the subject is calculated from the calculated relative displacement and the calculated absolute displacement. 2. The non-contact vibration detecting device according to claim 1, wherein the magnetic field generating means is an electromagnet and / or a permanent magnet. 3. The non-contact vibration detection device according to claim 1, wherein the magnetic detection means is a magnetic probe and / or a hall element formed by winding a conductive wire. 4. The non-contact vibration detecting device according to claim 1, wherein the vibration detecting means is an accelerometer and / or a strain gauge. 5. A magnetism detecting means and a vibration detecting means in at least one magnet selected from a superconducting magnet, a normal conducting magnet and a permanent magnet, the magnetism detecting means and vibration detecting means being opposed to the magnet in a non-contact manner and fixed on the same frame. The magnetic detection means and the signal processing means from the vibration detection means, the signal processing means calculates the relative displacement between the magnet and the gantry from the signal of the magnetic detection means, and the vibration detection means. The absolute displacement of the gantry is calculated from the signal, and the absolute displacement of the magnet is calculated based on the calculated relative displacement and the calculated absolute displacement. 6. The non-contact vibration detection device according to claim 5, wherein the magnetic detection means is a magnetic probe and / or a hall element formed by winding a conductive wire. 7. The non-contact vibration detecting device according to claim 5, wherein the vibration detecting means is an accelerometer and / or a strain gauge.