JP7542792B2 - Vibration test device and failure prediction method thereof - Google Patents

Description

The present invention relates to a vibration testing device for performing vibration characteristic tests and durability tests on industrial products such as aerospace equipment, automotive equipment, electronics products, and precision equipment, and more specifically to a vibration testing device with a failure prediction function and a failure prediction method for a vibration testing device.

Conventionally, vibration testing has been carried out using vibration testing equipment to perform vibration characteristic tests and durability tests on industrial products such as aerospace equipment, automotive equipment, electronics products, and precision instruments.

As disclosed in, for example, Patent Documents 1 and 2, the vibration testing device includes a movable part on which the test object is placed and a fixed part having a magnetic path member, and is configured to vibrate the movable part by passing an alternating current through the drive coil of the movable part so as to be perpendicular to the static magnetic field generated in the fixed part.

The vibration testing device is also configured to support the moving part with a spring and restrain the shaft of the moving part with a restraining bearing so that the moving part does not vibrate in any direction other than the desired direction.

Also provided are an AC power supply for passing an AC current through the drive coil of the moving part, and if an excitation coil is used for the magnetic path member, a DC power supply for passing a DC current through the excitation coil.

Such vibration testing equipment is generally configured to automatically stop for safety reasons if a malfunction occurs. However, depending on the type of test subject, vibration testing can take a long time, and users would want to avoid an occurrence where a malfunction occurs during a vibration test, causing the test to stop midway.

For this reason, in order to prevent breakdowns in vibration test equipment, parts are replaced regularly, and abnormal operation or noise is checked for during regular maintenance or during preliminary tests conducted before the actual vibration test to check for any abnormalities in the vibration test equipment.

Japanese Patent Application Publication No. 11-44606 JP 2014-74612 A JP 2005-62097 A

However, if checking for abnormal operation or noise is relied upon solely by the user's senses, there is a chance that abnormalities will be overlooked.
For this reason, Patent Document 3 proposes a configuration in which the transfer characteristics of the moving part are acquired and compared with pre-stored reference transfer characteristic data to determine whether an abnormal state exists.

By performing this type of anomaly determination based on the transfer characteristics, it is possible to determine whether or not there is a malfunction in the moving part. However, it is difficult to isolate and detect anomalies occurring in components of the vibration testing device, such as the moving coil, excitation coil, and restraint mechanism (such as the spring for suspending the moving part and the restraint bearing).

In addition, if moving parts or excitation coils break down, it may take a long time to arrange for replacement parts and perform the work, so it is advisable to discover any abnormalities early and prepare for replacement work before the vibration test equipment becomes unusable.

In view of the current situation, the present invention aims to provide a vibration testing device with a failure prediction function that can detect abnormalities in the vibration testing device at an early stage and prevent the failure from expanding, and a failure prediction method for the vibration testing device.

The present invention has been invented to solve the problems in the conventional technology as described above, and the vibration testing apparatus of the present invention comprises:
a movable part on which a test object is mounted;
A vibration testing apparatus comprising: a stationary portion having a magnetic path member having magnetic permeability and a magnetic flux generating means for generating a magnetic flux flowing through the magnetic path member,
A plurality of one-axis sensors for measuring at least one of an acceleration, a velocity, and a displacement of the movable part;
and a calculation device that performs failure prediction of the vibration testing apparatus based on outputs from the plurality of one-axis sensors.
The computing device includes:
The present invention is characterized in that crosstalk of the moving part is measured based on outputs from the plurality of one-axis sensors, and the failure prediction is performed based on the magnitude of the amplitude of the crosstalk.

In such a vibration test device,
The computing device includes:
At least one of the displacement amount and the vibration frequency of the movable part is measured based on the outputs from the plurality of single-axis sensors, and the failure prediction can be performed based on at least one of the displacement amount and the vibration frequency of the movable part.

The arithmetic device further comprises:
An excitation force coefficient is calculated based on the outputs from the plurality of single-axis sensors, and the failure prediction can be performed based on the excitation force coefficient.

Such a vibration test device is
The movable part includes a drive coil.
The drive coil may be configured so that a vibration signal required to impart a predetermined pattern of vibration to the test object is sent from a vibration control device.

In this case, the arithmetic device
Based on the vibration signal and the outputs from the multiple single-axis sensors, the frequency response of the vibration testing apparatus is measured, a resonant frequency of the frequency response is calculated, and the failure prediction is performed based on the resonant frequency.

In such a vibration test device,
The computing device may be configured to issue an alarm if a failure of the vibration testing device is predicted.
In addition, in such a vibration test device,
A movable part suspension spring that holds the movable part in a movable state is further provided,
The plurality of one-axis sensors may be disposed vertically above the movable part suspension spring.
The plurality of one-axis sensors may be disposed at positions on the movable portion other than the surface on which the device under test is placed.
In this case, the plurality of one-axis sensors can be disposed on a side surface of the movable portion, close to a surface on which the device under test is placed.

The method for predicting a failure of a vibration testing apparatus according to the present invention further comprises the steps of:
a movable part on which a test object is mounted;
A method for predicting a failure of a vibration testing apparatus including a fixed portion having a magnetic path member having magnetic permeability and a magnetic flux generating means for generating a magnetic flux flowing through the magnetic path member, comprising:
The crosstalk of the movable portion is measured using a plurality of one-axis sensors , and the failure prediction is performed based on the magnitude of the amplitude of the crosstalk.

In such a failure prediction method, at least one of the displacement amount and the vibration frequency of the movable part is measured, and the failure prediction can be performed based on at least one of the displacement amount and the vibration frequency of the movable part.

In addition, the excitation force coefficient can be calculated, and the failure prediction can be performed based on the excitation force coefficient.

In addition, the frequency response of the vibration testing apparatus is measured from the vibration signal input to the drive coil of the movable part and the amplitude of the movable part, the resonant frequency of the frequency response is calculated, and the failure prediction can be performed based on the resonant frequency.
In addition, in such a failure prediction method,
The plurality of one-axis sensors may be disposed vertically above a movable part suspension spring that holds the movable part in a movable state.
The plurality of one-axis sensors may be disposed at positions on the movable portion other than the surface on which the device under test is placed.
In this case, the plurality of one-axis sensors can be disposed on a side surface of the movable portion, close to a surface on which the device under test is placed.

According to the present invention, a calculation device can automatically predict failures based on the output from a moving part sensor installed in the moving part, making it possible to detect abnormalities in the vibration testing device early and prevent the failure from expanding.

In addition, by using the moving part sensor and other sensors, it is possible to isolate and diagnose abnormalities in the vibration test equipment, enabling early detection of abnormalities in the vibration test equipment and encouraging the user to repair the equipment by replacing parts, etc., before it breaks down.

FIG. 1 is a schematic diagram showing an embodiment of a vibration testing device according to the present invention.

Hereinafter, embodiments (examples) of the present invention will be described in more detail with reference to the drawings.
FIG. 1 is a schematic diagram showing an embodiment of a vibration testing device according to the present invention.
As shown in FIG. 1, a vibration testing apparatus 10 of this embodiment includes a fixed portion 11 having a magnetic path member 16 and the like, and a movable portion 30 on which a device under test (not shown) is mounted.

The fixed portion 11 includes a magnetic path member 16 made of a magnetically permeable material such as iron, and an excitation coil 14 (magnetic flux generating means) that generates a magnetic flux that flows through the magnetic path member 16. The excitation coil 14 is arranged so that, when a DC voltage is applied from a constant voltage source (not shown), a constant magnetic flux flows through the magnetic path member 16 and a magnetic field (static magnetic field) that is perpendicular to the drive coil 36 inserted in the gap portion 24 of the magnetic path member 16 is generated.

The movable part 30 includes a test stand 33 on which a test object (not shown) is placed, and a movable part suspension spring 34 that connects the movable part 30 to the fixed part 11 and holds the movable part 30 in a movable state. The bottom of the movable part 30 is provided with a drive coil 36 that is inserted into the gap 24 of the magnetic path member 16.

The drive coil 36 is connected to a vibration control device 48 via a power amplifier 46, and is configured so that the vibration signal required to impart a predetermined pattern of vibration to the test subject can be sent from the vibration control device 48 via the power amplifier 46.

The movable part 30 also has a shaft (constraint shaft 39) that is inserted into a bearing 22 provided in the fixed part 11. A constraint bearing 42 is provided in the bearing 22, and the constraint shaft 39 of the movable part 30 is constrained by this constraint bearing 42.
The movable part 30 has its horizontal and vertical range of motion limited to a predetermined range by a restraining mechanism having an axis (restraint shaft 39), bearing 22, restraint bearing 42, and the movable part suspension spring 34 described above.

As a restraint mechanism, a damper (not shown) can be provided between the fixed part 11 and the movable part 30. By providing a damper in this manner, it is possible to prevent the movable part 30 from being damaged by being subjected to an excessive vibration force.

The restraint mechanism may include all of the mechanisms described above, or may include only some of the mechanisms. The type of restraint mechanism may be changed as appropriate depending on the specifications of the vibration test device 10.

In this embodiment, the excitation coil 14 is configured to generate a static magnetic field, but a permanent magnet can be provided instead of the excitation coil 14. In addition, in order to prevent the vibration test device 10 from breaking down due to heat generated by passing a current through the excitation coil 14 or the drive coil 36, it is preferable to provide a cooling means such as air cooling or water cooling.

In the vibration testing device 10 of this embodiment, which is configured in this manner, a three-axis sensor 31 is provided as a moving part sensor in the moving part 30. The three-axis sensor 31 can measure at least one of the acceleration, velocity, and displacement in the X-axis direction, which coincides with the vibration direction of the moving part 30, and the Y-axis and Z-axis directions perpendicular to the X-axis.

In this embodiment, the vibration direction of the movable part 30 is one direction, so this is aligned with the X-axis direction. However, if the vibration direction of the movable part 30 is two directions, for example, the three-axis sensor 31 can be provided on the movable part 30 so that the vibration directions are aligned with the X-axis direction and the Y-axis direction, respectively.

The three-axis sensor 31 is connected to a calculation device 50, such as a computer, and the calculation device 50 is configured to predict failures of the vibration testing device 10 based on the output of the three-axis sensor 31.

The computing device 50 may be, for example, a personal computer or a microcontroller, and may be incorporated into the vibration control device of the vibration testing device 10.

The arithmetic unit 50 performs failure prediction for the vibration testing apparatus 10 as follows.
(1) Crosstalk Measurement Crosstalk, which is vibration generated in the excitation axis of the vibration testing device 10, i.e., in this embodiment, other than the X-axis, is detected based on the output of the triaxial sensor 31. In this embodiment, the vibration in the Y-axis direction and the vibration in the Z-axis direction are the crosstalk.

Although crosstalk occurs slightly due to so-called mechanical play, the crosstalk becomes particularly large due to failure or severe wear of the restraining mechanism.
The computing device 50 is configured to issue an alarm when the amplitude of the detected crosstalk becomes larger than a predetermined amplitude threshold value that is set in advance. The alarm may be displayed on a display means or may be issued by sound such as a buzzer.

In this way, by measuring crosstalk using the three-axis sensor 31, wear and tear on the restraint mechanism can be detected, and an alarm can be issued to the user before the restraint mechanism breaks down, prompting them to replace the restraint mechanism, etc.

(2) Displacement Measurement Based on the output of the three-axis sensor 31, the displacement amount and the vibration frequency are detected as the displacement of the movable part 30.
The displacement of the movable part 30 changes due to wear of the restraining mechanism, particularly the movable part suspension spring 34 .

The computing device 50 is configured to issue an alarm when the detected displacement of the movable part 30 becomes larger than a predetermined displacement threshold value set in advance, or when the detected vibration frequency of the movable part 30 becomes smaller than a predetermined vibration frequency threshold value.

In this way, by measuring the displacement of the movable part 30 using the three-axis sensor 31, wear and tear on the restraint mechanism, particularly the movable part suspension spring 34, can be detected, and an alarm can be issued to the user before the restraint mechanism breaks down, urging them to replace the restraint mechanism, etc.

In this embodiment, the displacement of the movable part 30 is detected using the three-axis sensor 31, but it can also be configured to detect the displacement by providing a displacement sensor (not shown) separate from the three-axis sensor 31.

(3) Measurement of Excitation Force Coefficient Based on the output of the three-axis sensor 31, the excitation force coefficient of the movable part 30 is calculated according to the following formula (1).

Normally, the greater the current applied to the drive coil 36, the greater the acceleration. However, if the drive coil 36 or the excitation coil 14 malfunctions or wears out rapidly, the acceleration will decrease even if the same current is passed through the drive coil 36.

The computing device 50 is configured to issue an alarm when the calculated excitation force coefficient becomes smaller than a predetermined excitation force coefficient threshold value that has been set in advance.

In this way, by measuring the excitation force coefficient using the three-axis sensor 31, wear and tear on the drive coil 36 and excitation coil 14 can be detected, and an alarm can be issued to the user before the drive coil 36 and excitation coil 14 break down, prompting them to replace the drive coil 36 and excitation coil 14, etc.

(4) Measurement of transmission characteristics Based on the vibration signal input from the vibration control device to the vibration testing device 10 and the output of the three-axis sensor 31 (amplitude of the movable part 30), the transmission characteristics (frequency response) of the vibration testing device are measured and its resonant frequency is calculated.

The resonant frequency is specific to the configuration of the vibration testing device 10, but it can change due to failure or severe wear of the drive coil 36 or the restraint mechanism.
The computing device 50 is configured to issue an alarm when the calculated resonant frequency becomes smaller than a pre-set resonant frequency threshold.

In this way, the resonant frequency can be calculated by measuring the transmission characteristics, and wear and tear on the drive coil 36, the restraint mechanism, etc. can be detected from this resonant frequency. Before the drive coil 36 or the restraint mechanism breaks down, an alarm can be issued to the user, prompting them to replace the drive coil 36 or the restraint mechanism, etc.

In the embodiment described above, at least one of the acceleration, velocity, and displacement in each axis direction is measured using a three-axis sensor 31, but the invention is not limited to a three-axis sensor 31. For example, it is also possible to use three one-axis sensors for measurement, or to configure the one-axis sensor to be aligned with the required axis direction for measurement.

In addition to failure prediction, for example, a thermal sensor such as a thermocouple can be provided in the drive coil 36 to measure the temperature of the drive coil 36, and the calculation device 50 can perform failure prevention based on this temperature.

(5) Measurement of Temperature of the Drive Coil The temperature of the drive coil 36 is measured based on the output of the thermal sensor.
Since the drive coil 36 is fixed to the movable part 30 with an adhesive or the like, if the temperature of the drive coil 36 becomes too high, the adhesive deteriorates and the drive coil 36 may become loose.

The computing device 50 is configured to issue an alarm when the temperature of the drive coil 36 exceeds a preset limit temperature threshold. The limit temperature threshold can be set appropriately depending on the specifications of the vibration test device 10 and the type of adhesive, and can be set to, for example, 90°C to 200°C.

In this way, by taking measures to prevent failures as well as predicting them, it is possible to create a vibration testing device 10 that is less prone to failures.

The above describes a preferred embodiment of the present invention, but the present invention is not limited to this. For example, in the above embodiment, a thermal sensor is provided to prevent failures, but the present invention is not limited to this, and various measures may be taken to prevent failures, and various modifications are possible without departing from the purpose of the present invention.

REFERENCE SIGNS LIST 10 Vibration test device 11 Fixed portion 14 Excitation coil 16 Magnetic path member 22 Bearing 24 Gap portion 30 Movable portion 31 Three-axis sensor 33 Test stand 34 Movable portion suspension spring 36 Drive coil 39 Restraint shaft 42 Restraint bearing 46 Power amplifier 48 Vibration control device 50 Calculation device

Claims (16)

a movable part on which a test object is mounted;
A vibration testing apparatus comprising: a stationary portion having a magnetic path member having magnetic permeability and a magnetic flux generating means for generating a magnetic flux flowing through the magnetic path member,
A plurality of one-axis sensors for measuring at least one of an acceleration, a velocity, and a displacement of the movable part;
and a calculation device that performs failure prediction of the vibration testing apparatus based on outputs from the plurality of single-axis sensors.
The computing device includes:
A vibration testing apparatus comprising: a vibration sensor for detecting a vibration of the movable portion; a vibration sensor for detecting a vibration of the movable portion; The computing device includes:
2. The vibration testing device according to claim 1, wherein at least one of a displacement amount and a vibration frequency of the movable part is measured based on outputs from the plurality of one-axis sensors, and the failure prediction is performed based on at least one of the displacement amount and the vibration frequency of the movable part. The computing device includes:
3. The vibration testing apparatus according to claim 1, further comprising: a vibration force coefficient calculated based on outputs from the plurality of one-axis sensors; and a failure prediction performed based on the vibration force coefficient. The movable part includes a drive coil.
4. The vibration testing device according to claim 1, wherein said drive coil is configured so that a vibration signal required for applying a predetermined pattern of vibration to said test object is sent from a vibration control device to said drive coil. The computing device includes:
5. The vibration testing apparatus according to claim 4, wherein a frequency response of the vibration testing apparatus is measured based on the vibration signal and outputs from the plurality of single-axis sensors, a resonance frequency of the frequency response is calculated, and the failure prediction is performed based on the resonance frequency. The vibration testing device according to any one of claims 1 to 5, characterized in that the computing device is configured to issue an alarm when a failure of the vibration testing device is predicted. A movable part suspension spring that holds the movable part in a movable state is further provided,
7. The vibration testing device according to claim 1, wherein the plurality of one-axis sensors are disposed vertically above the movable portion suspension spring. 8. The vibration testing device according to claim 1, wherein the plurality of one-axis sensors are arranged at positions on the movable portion other than a surface on which the test object is placed. 9. The vibration testing device according to claim 8, wherein the plurality of one-axis sensors are arranged on a side surface of the movable portion closer to a surface on which the test object is placed. a movable part on which a test object is mounted;
A method for predicting a failure of a vibration testing apparatus including a fixed portion having a magnetic path member having magnetic permeability and a magnetic flux generating means for generating a magnetic flux flowing through the magnetic path member, comprising:
A failure prediction method comprising: measuring crosstalk of the movable portion using a plurality of uniaxial sensors ; and predicting failure based on the magnitude of the amplitude of the crosstalk. 11. The failure prediction method according to claim 10 , further comprising measuring at least one of a displacement amount and a vibration frequency of the movable part, and performing the failure prediction based on at least one of the displacement amount and the vibration frequency of the movable part. 12. The failure prediction method according to claim 10 , further comprising the steps of: calculating an excitation force coefficient; and performing the failure prediction based on the excitation force coefficient. A failure prediction method according to any one of claims 10 to 12, characterized in that a frequency response of the vibration testing apparatus is measured from a vibration signal input to a drive coil of the movable part and an amplitude of the movable part, a resonant frequency of the frequency response is calculated, and the failure prediction is performed based on the resonant frequency. 14. The failure prediction method according to claim 10, wherein the plurality of one-axis sensors are disposed vertically above a movable part suspension spring that holds the movable part in a movable state. 15. The failure prediction method according to claim 10, wherein the plurality of one-axis sensors are arranged at positions on the movable part other than a surface on which the device under test is placed. 16. The failure prediction method according to claim 15, wherein the plurality of one-axis sensors are arranged on a side surface of the movable part closer to a surface on which the test object is placed.

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