JP2007322339A - Method and device for testing vibration - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for testing vibration that substitutes a small mechanical piston cylinder for an electro-dynamic vibration tester of a vibration generation source and uses compressed air capable of easily generating a large excitation force, as power, and a device therefor. <P>SOLUTION: In the method or the device for exciting a vibration table fixed to a frame via a spring, the impulsive force of the compressed air is converted to the reciprocation of the piston cylinder and thereby impulsive waves are continuously generated and then converted vibrations by the impulsive waves to random vibrations, by mounting the end surface of the piston cylinder on the lower surface of the vibration table diagonally. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  In a vibration testing device that performs vibration testing of a sample to be measured mounted on a vibration table, vibration is generated by impact excitation with an air hammer in the XYZ axis direction and the rotation direction of each axis from below the vibration table fixed to the pedestal via a spring. The technology of generation.

  Conventionally, in a vibration test apparatus, an electrodynamic vibration generator has been proposed as a general method for generating vibration that applies vibration to a sample to be measured (see, for example, Patent Document 1). Below, the prior art of a general vibration generator is demonstrated using FIG.

  In the electrodynamic vibration generator, the sample 50 to be measured is mounted on the vibration table 51. To generate vibration of the vibration table 51, an alternating current from the power amplifier 57 is passed through the drive coil 52 of the tester body, and a magnetic field is applied. The movable part such as the vibration table 51 connected to the drive coil 52 is changed to mechanical vibration.

  The principle of operation is to convert the generated magnetic field into a force (vibration) based on Fleming's left-hand rule, and convert the magnetic field generated in the coil into a force (vibration). When a direct current from the excitation power source 58 is passed, a magnetic flux is generated, a direct current magnetic field perpendicular to the line of the drive coil 52 is created in the air gap, and the drive coil 52 attached to the vibration table 51 held by a spring in the air gap of the magnetic path 53. The vibration table 51 is caused to vibrate by passing an alternating current through the vibration table 51.

  Since the drive coil 52 and the vibration table 51 are generally not flat in frequency characteristics of mechanical impedance, a vibration sensor 55 for detecting the acceleration level is attached to the vibration table 51 and used in combination with the vibration controller 56 built in the current generator. The vibration level on the vibration table 51 is monitored and the current (AC) generated from the power amplifier 57 is controlled to obtain an arbitrary vibration level. Then, in order to generate multi-axial vibration in three axes and six directions, the vibration controller 56 including the same number of power amplifiers 57 as that of at least three electrodynamic vibration test machines is used in combination to constitute a test apparatus. did.

However, in such a conventional electrodynamic vibration tester, a magnetic field is generated by the current flowing through the drive coil inside the tester and converted into a vibration excitation force.
(1) In order to obtain a large excitation force with an electrodynamic vibration tester, it is necessary to pass a large current through the drive coil, so it is necessary to increase the coil capacity (increase the number of turns and increase the wire diameter). However, as a result, the excitation force per test machine becomes small due to the restriction of coil heat generation.
(2) In order to obtain a large excitation force, the coil size is larger than that of the test table size. Therefore, it is necessary to provide a plurality of stages of conversion bearings joint-connected to the vibration table. If a conversion bearing is added, the weight of the bearing will increase, causing the problem of reducing the excitation force and complicating the mechanical design.

In addition, due to the complicated structure including the conversion bearing, the weight of the entire system including the testing machine main body, the bearing section, and the vibration table increases, the frequency range in which vibration is generated does not extend, and a few kilohertz or less is the limit. .
(3) In the case of a three-axis six-direction multi-axis test apparatus, the problems (1) and (2) above become more complicated, and it is difficult to obtain vibration characteristics results even when extended to a large vibration table size. It becomes complicated.
(4) In the case of a multi-axis testing machine with a high excitation force, a large capacity and number of power amplifiers including a control device are also required. Become.
Japanese Patent No. 3035280

  In order to solve the above problems, in the present invention, instead of an electrodynamic vibration tester that is a vibration generation source, a small mechanical piston cylinder is used, and compressed air that can easily generate a large excitation force is used as power. A vibration test apparatus is provided. A shock wave is generated by striking a piston inside the cylinder against the inner and outer walls with compressed air, and a vibration generating mechanism is realized that converts it into random wave vibration via a multi-structure table.

  A first invention is a vibration test method for vibrating a vibration table fixed to a gantry via an elastic member, and continuously generates shock waves by changing the impact force of compressed air into a reciprocating motion of a piston cylinder. And a step of transmitting the shock wave to the vibration table via an end surface of the piston cylinder attached obliquely to the lower surface of the vibration table.

  That is, according to the first invention, the vibration test apparatus is composed of a vibration table on which a sample is placed and an impact generator using compressed air that generates a shock wave, and an impact force from the impact generator is applied to the vibration table. As a result, the input shock pulse is changed to a broadband random vibration having a wide frequency band through the transmission path of the table, and the piston cylinder of the shock generator reciprocates to generate a continuous random vibration. It becomes possible. A compact vibration test capable of covering even high-frequency vibrations is possible by the mechanism of vibration generation by the piston cylinder structure using the impact force of compressed air of the present invention.

  The piston cylinder outer end is attached to the lower surface of the vibration table obliquely, and a shock wave is applied to the vibration table, so that the acceleration level is higher and higher than that of a conventional electrodynamic vibration tester using a voice coil. It becomes possible to obtain a random vibration with a frequency.

  The second invention relates to the vibration test method according to the first invention, wherein an inner end surface of the piston cylinder includes a buffer member including a resin member.

  That is, according to the second invention, by covering the end surface of the piston cylinder with a buffer member such as a polymer, for example, the impact of the repeated piston can be mitigated and consequently wear can be prevented. In addition, the buffer member has a role as a programmer for changing the vibration mode, and the random vibration in the vibration table can be changed in a wide range by changing various materials.

  In a third aspect of the invention, the acceleration level of the shock wave is made variable by adjusting an air flow rate of an air valve provided in an air supply path between an external compressor that is a power source of compressed air and the piston cylinder. The present invention relates to the vibration test method according to the first or second invention.

  That is, according to the third aspect of the invention, the acceleration level can be changed by passing the air supply path to the air chamber in the piston cylinder and supplying the pressure of compressed air, which is a power source to be supplied, between the external compressor and the piston cylinder. The air valve provided in the air supply path can be changed by changing the flow rate of the compressed air.

  According to a fourth aspect of the invention, the vibration table has a structure in which a plurality of table layers made of materials having different shock wave transmission characteristics are stacked in layers via intermediate connection spacers. The present invention relates to the vibration test method according to any one of the three inventions.

  That is, according to the fourth aspect of the invention, the vibration table is composed of a lower table and an upper table made of materials having different frequency characteristics, and a multilayer stack comprising the entire table via intermediate connection spacers having different frequency characteristics. By using a vibration table with a structure, the shock pulse input from the lower part passes through a plurality of transmission paths having different frequency characteristics, so that the frequency characteristics of the response random vibration of the upper table part on which the upper test sample is mounted are further increased. Broadband.

  Further, by passing through a plurality of complicated transmission paths, the effect of converting the large impact energy applied to the lower table of the shock pulse input unit into a uniform random vibration level on the upper table surface is produced.

As described above, according to the present invention, the following effects are produced.
(1) The vibration test apparatus is composed of a vibration table on which a sample is placed and a shock wave generator using compressed air that generates a shock wave. The shock input from the shock wave generator is applied to the vibration table by applying the shock to the vibration table. The pulse is changed to a broadband random vibration having a wide frequency band through the transmission path of the vibration table, and the random vibration can be repeatedly generated by continuously operating.

The vibration test method capable of covering up to high-frequency vibrations in a small size is realized by the mechanism of vibration generation using the piston cylinder structure utilizing the impact force of air pressure of the present invention.
(2) By covering the end surface of the piston cylinder with a buffer member such as a polymer, for example, the impact of the repeated piston can be mitigated and, as a result, wear can be prevented. It has a role as a programmer that changes the vibration mode, and it is possible to change the random vibration in the vibration table over a wide range by changing the material.
(3) The acceleration level can be varied via the air supply path to the air chamber in the piston cylinder, and the pressure of compressed air as the power source to be supplied is provided in the air supply path between the external compressor and the piston cylinder. By changing the flow rate of the compressed air with the air valve, it can be changed.
(4) The vibration table is composed of a lower table and an upper table made of materials having different frequency characteristics, and further, a multi-layered structure vibration table that constitutes the entire table through intermediate connection spacers having different frequency characteristics. Thus, by passing the shock pulse input from the lower part through a plurality of transmission paths having different frequency characteristics, the frequency characteristic of the response random vibration of the upper table portion on which the upper test sample is mounted becomes wider.

  Further, by passing through a plurality of complicated transmission paths, the effect of converting the large impact energy applied to the lower table of the shock pulse input unit into a uniform random vibration level on the upper table surface is produced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows a principle configuration of a vibration generating mechanism in a vibration test apparatus according to an embodiment of the present invention. The vibration test apparatus includes a vibration table 2 on which a sample to be measured for vibration test is placed, and an impact generator 1 using a piston cylinder using compressed air as a vibration generation source for applying vibration to the vibration table 2. . By applying an impact force from the impact generator 1 to the vibration table 2, a wide range of random vibrations (overlapping vibrations of a plurality of frequencies) in which the input impact pulse has a wide frequency band through the transmission path of the vibration table 2. A vibration test apparatus that repeatedly generates random vibrations can be realized by continuously operating the shock generator 1 by using a method that changes to (irregular waveform vibrations).

  This embodiment uses a plurality of small mechanical piston cylinders as described above in place of the electrodynamic vibration tester, which is a conventional vibration generation source, and uses compressed air that can easily generate a large excitation force as power. Is.

  Although not specifically shown, the vibration table 2 is fixed to the frame of the vibration test apparatus at the four corners via a spring mechanism using an elastic member such as a compression coil spring, and the XYZ three axes and the rotation of each axis are combined for six freedoms. The structure is secured.

  The vibration control unit 100 controls the flow rate of the compressed air supplied to the piston cylinder of the shock generator 1 to change the acceleration level of the shock wave to the vibration table 2, and the compression from the external compressor An air valve 101 provided in an air supply path for air, a regulator 102 that adjusts the pressure of air, and a timing valve 103 that switches the supply timing of compressed air supplied to a plurality of piston cylinders as the impact generator 1. The

  Further, the vibration control unit 100 receives the signal of the sensor 104 that detects the acceleration of the shock wave attached to the vibration table 2 and receives an air valve (air valve) 101 and a regulator (pressure regulator) so as to obtain an appropriate acceleration level. ) 102 controls the flow rate of the compressed air supplied to the piston cylinder of the impact generator 1.

  Further, as shown in FIG. 1, at least three piston cylinders are used at the bottom of the vibration table 1, and the piston cylinders are divided into three axes (X / (Y / Z axis), and obliquely attached to the lower part of the vibration table 1 (for example, an attachment angle is set to about 45 °), a multi-axis random vibration of a 3-axis 6-degree-of-freedom (6 DOF) shock wave input method is generated. It becomes a vibration test device.

  In this case, the acceleration component on each axis of the generated vibration differs depending on the external dimensions of the vibration cylinder 2 and the piston cylinder serving as the impact generator 1, the number of piston cylinders attached, the angle of attachment, and the like. Specifications such as dimensions, number of mounting, and mounting angle of these piston cylinders are adjusted and determined so as to be the best from the characteristic data.

  As described above, the multi-axis vibration characteristics are improved by directly connecting the piston cylinder to the lower part of the vibration table every three axes. Further, by combining this single test apparatus as a basic set and combining a plurality of test apparatuses, even when the table size is expanded, good vibration characteristics can be obtained. Since the structure of the vibration generator is simple as described above, it does not require complicated mechanical design calculations, and the power amplifier and controller associated with the conventional technology are unnecessary, so the entire system is simplified. And cost can be reduced.

  FIG. 2 shows a configuration example of an impact generator according to the embodiment of the present invention. The impact generator 1 is made of a polymer (resin) or the like that has a role of relaxing the impact force by striking the piston 11 to prevent breakage and changing the vibration mode inside the piston cylinder whose impact force is the pressure of compressed air. A housing portion (attachment portion to the vibration table 2) 15 having a programmer (buffer member) 13 made of a material, a piston 11 including a steel piston, an air chamber 12 for compressed air, a suction port 17 and a discharge port 16 It consists of mechanical parts. The cap 18 is for facilitating replacement of components in the piston cylinder, and the outer end portion of the housing portion 15 is connected to the vibration table 2 so that the table mounting surface 14 is cut at a certain angle. Yes.

  When a continuous pulse of compressed air is supplied to the air chamber 12, the piston 11 moves and strikes the programmer 13 due to the pressure difference between both ends of the piston 11, and the repulsive force when the programmer 13 strikes and the position of the programmer 13 The process of returning to the air chamber 12 side by the pressure drop of the air chamber 12 via the air path in the piston is repeated, and converted into a continuous reciprocating motion of the piston 11.

  That is, the shock wave generated by repeatedly hitting the programmer 13 attached to the inner end of the housing portion 15 through the reciprocating operation of the piston 11 main body and the programmer 13 continuously driven by compressed air causes the piston cylinder outer end portion. Is transmitted to the vibration table 2 of the vibration test apparatus to be connected.

  As shown in FIG. 2, the shock wave transmission mechanism that transmits a shock wave from the piston cylinder to the vibration test apparatus has a configuration in which a table mounting surface 14 of the piston cylinder that is processed obliquely is attached to the lower part of the vibration table 2. ing. By applying a shock wave to the vibration table 2 via this shock wave transmission mechanism, conversion to a random vibration with a high acceleration level and a high frequency is realized by a conventional electrodynamic vibration tester using a voice coil. (The excitation force of the vibration generator is more than 10 times the conventional level).

  Also, an air valve provided with a pressure of compressed air as a power source to be supplied to an air chamber 12 in the piston cylinder in a hose path between an external compressor and the piston cylinder via an air hose (air supply path). With the (air valve), the flow rate of the compressed air can be limited or variable, and the acceleration level of the impact generator 1 can be changed.

  FIG. 3 shows the behavior of the vibration table in the vibration test apparatus according to the embodiment of the present invention. The upper diagram shows the shock wave applied to the vibration table 2 by the shock generator 1 by the change in acceleration G (m / s2) with respect to time (t: Seconds), and the lower diagram shows the frequency f in the vibration table 2. Random vibrations captured with 6 degrees of freedom in each of the three axes with respect to (1 / t) are expressed as energy per 1 Hz (G2 / Hz). With this data, it can be understood that the shock wave generated by the shock generator 1 is converted into random vibration in the vibration table 2 and extends to vibration in a high frequency region.

  FIG. 4 shows an example of the structure of the vibration table according to the embodiment of the present invention. As shown in the figure, the vibration table 2 of the present invention has a table composed of a honeycomb structure made of materials having different frequency characteristics at the lower part and the upper part as a unit, and further through intermediate connection spacers having different frequency characteristics. Thus, it has a multiple structure constituting the entire vibration table.

  By using such a vibration table 2, the frequency characteristics of the response random vibration of the upper table portion on which the upper test sample is mounted can be further increased by passing the shock pulse input from the lower part through a plurality of transmission paths having different frequency characteristics. Broadband.

  Further, by passing through a plurality of complicated transmission paths, there is an effect that large impact energy applied to the lower table of the shock pulse input unit is converted to a uniform random vibration level on the upper table surface.

The embodiments of the present invention described above are as shown in the following supplementary notes.
(Additional remark 1) It is a vibration test method which vibrates the vibration table fixed to the mount via the elastic member,
Changing the impact force of the compressed air into a reciprocating motion of the piston cylinder and continuously generating shock waves;
Transmitting the shock wave to the vibration table via an end face of the piston cylinder attached obliquely to the lower surface of the vibration table;
A vibration test method characterized by comprising:
(Supplementary note 2) The vibration test method according to supplementary note 1, wherein an inner end surface of the piston cylinder includes a programmer including a resin member.
(Supplementary Note 3) The acceleration level of the shock wave is variable by adjusting the air flow rate of an air valve provided in an air supply path between an external compressor that is a power source of compressed air and the piston cylinder. 3. The vibration test method according to appendix 1 or 2, which is characterized.
(Supplementary note 4) Any one of Supplementary notes 1 to 3, wherein the vibration table has a structure in which a plurality of table layers made of materials having different shock wave transmission characteristics are stacked in layers via intermediate connection spacers. The vibration test method described in 1.
(Supplementary Note 5) The piston cylinder attached to the lower surface of the vibration table is composed of three or more including at least the excitation directions of the XYZ axes, and the number of piston cylinders and the mounting angle are optimized from the characteristic data. The vibration test method according to any one of appendices 1 to 4, wherein:
(Supplementary note 6) The vibration test method according to supplementary note 5, wherein the piston cylinder mounting set is defined as one unit, and at least two sets are combined.
(Appendix 7) A vibration test apparatus including a vibration table fixed to a gantry via an elastic member,
An impact generator that continuously generates shock waves by changing the impact force of compressed air into a reciprocating motion of a piston cylinder; and
A shock wave transmission mechanism that transmits the shock wave to the vibration table via an end surface of the piston cylinder that is obliquely attached to a lower surface of the vibration table;
A vibration test apparatus comprising:

It is a figure which shows the principle structure of the vibration generation mechanism in the vibration test apparatus which becomes embodiment of this invention. It is a figure which shows one structural example of the impact generator which becomes embodiment of this invention. It is a figure which shows the behavior of the vibration table in the vibration test apparatus which becomes embodiment of this invention. It is a figure which shows one structural example of the vibration table which becomes embodiment of this invention. Configuration example of a conventional electrodynamic vibration generator

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Shock generator 2 Vibration table 11 (Steel) piston 12 Air chamber 13 Programmer (polymer)
14 Table mounting surface 15 Housing portion 16 Discharge port 17 Suction port 18 Cap 100 Excitation control unit 101 Air valve 102 Regulator 103 Timing valve 104 Sensor

Claims (5)

A vibration test method for vibrating a vibration table fixed to a gantry via an elastic member,
Changing the impact force of the compressed air into a reciprocating motion of the piston cylinder and continuously generating shock waves;
Transmitting the shock wave to the vibration table via an end face of the piston cylinder attached obliquely to the lower surface of the vibration table;
A vibration test method characterized by comprising:   The vibration test method according to claim 1, wherein an inner end surface of the piston cylinder includes a buffer member including a resin member.   The acceleration level of the shock wave is variable by adjusting an air flow rate of an air valve provided in an air supply path between an external compressor that is a power source of compressed air and the piston cylinder. Item 3. The vibration test method according to Item 1 or 2.   4. The structure according to claim 1, wherein the vibration table has a structure in which a plurality of table layers made of materials having different transfer characteristics of the shock wave are stacked in layers via intermediate connection spacers. Vibration test method. A vibration test apparatus comprising a vibration table fixed to a gantry via an elastic member,
An impact generator that continuously generates shock waves by changing the impact force of compressed air into a reciprocating motion of a piston cylinder; and
A shock wave transmission mechanism for transmitting the shock wave to the vibration table via an end face of the piston cylinder attached obliquely to the lower surface of the vibration table;
A vibration test apparatus comprising:

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