JP2002181655A - Device for protecting rotation moment of vibration table - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device for protecting rotation moment of a vibration table achieving a smaller size and a lower cost. SOLUTION: The device comprises a vibration table for placing a test specimen, a rotation moment measuring section 25 for measuring the rotation moment of the vibration table, and an excitation stopping section 26 for inputting the output of the rotation moment measuring device 25 and controlling for stopping excitation when the rotation moment of the vibration table exceeds a permissible range.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibrating apparatus for testing the durability of a specimen by applying vibration to the specimen.

[0002]

2. Description of the Related Art In a vibrating apparatus for testing the durability and the like of a specimen by applying a vertical vibration to the specimen on a shaking table, a vibration direction is obtained as a result of coupled motion of the shaking table and the specimen. Is generated around the center axis. When the rotational movement occurs, there is a problem that the cylinder of the vibrator is damaged. For this reason, the conventional vibration device employs a protective structure that dynamically suppresses the rotational moment generated by the vibration with a hydrostatic bearing type guide, etc., so that the rotational force exceeding the specified value is not applied to the vibration mechanism. are doing.

[0003]

However, the structure in which the rotational moment is suppressed by the hydrostatic bearing type guide requires a large installation space, restricts the structure and arrangement of the entire shaking table, and reduces the cost in construction and maintenance. It is expensive and not economical. Furthermore, there is a problem that contamination (contamination) due to the static pressure bearing oil occurs, so that it cannot be used in a clean room.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a shaking table rotational moment protection device that realizes downsizing and cost reduction.

[0005]

According to a first aspect of the present invention, there is provided a vibration table on which a specimen is mounted, a rotation moment measuring section for measuring a rotation moment of the vibration table, and a rotation moment measuring section. A vibration stop unit that controls to stop vibration when an output is input and the rotational moment of the vibration table exceeds an allowable range.

In this shaking table rotational moment protection device, the generation of a rotational moment is detected by a rotational moment measuring unit, and when the rotational moment exceeds an allowable range, the vibration is stopped. For this reason, a bearing type guide for suppressing the rotational moment is not required.

According to a second aspect of the present invention, in the vibration table rotational moment protection device according to the first aspect, the rotational moment measuring unit includes a pair of acceleration detectors provided on the vibration table and the vibration table. And an inertia moment input section for inputting the moment of inertia of the specimen.
A rotational moment is calculated based on the acceleration detected by the acceleration detector and the moment of inertia of the shaking table and the specimen.

In this vibration table rotational moment protection device, the angular velocity of the vibration table is obtained from the acceleration detected by a pair of acceleration detectors provided on the vibration table. The rotational moment is calculated using the angular velocity and the moment of inertia.

[0009]

Next, embodiments of the present invention will be described with reference to the drawings. 1 and 2, reference numeral 1 denotes a vibration table. The shaking table 1 is provided with a vibrator 1
Supported by A. Reference numeral 2 denotes a specimen placed on a shaking table. On both sides of the center O ₀ of the shaking table 1, acceleration detectors 5 and 6 are provided, respectively. In the drawing, r is the distance from the center O ₀ of the shaking table to the center O ₁ of the specimen, R is the distance from the center O ₀ of the shaking table to the acceleration detectors 5 and 6, and X1 ″ and X2 ″ are the acceleration detectors, respectively. 5,6
Is the acceleration on the shaking table 1 detected by.

FIG. 3 shows a block diagram of the vibration table rotational moment protection device. In the figure, reference numerals 5 and 6 denote acceleration detectors, and reference numeral 7 denotes a subtractor for calculating a difference (X1 "-X2") between the accelerations X1 "and X2" detected by the acceleration detectors 5 and 6. Also, 10 is the moment of inertia input unit, and outputs switched by the switching means 11 to one of the moment of inertia I _A by input from the moment of inertia I _B or external by calculation.
Numeral 12 denotes an arithmetic unit. When an inertia moment given by the inertia moment input unit 10 is defined as I, I / (2
R) is output. Reference numeral 15 denotes a D / A converter, and reference numeral 16 denotes a multiplier for calculating a product of (X1 "-X2") and I / (2R). Reference numeral 20 denotes an absolute value processor that calculates the absolute value of the rotational moment, and reference numeral 21 denotes a comparator that compares the absolute value processed rotational moment with a predetermined allowable value. The acceleration detectors 5, 6,
Subtracter 7, inertia moment input unit 10, arithmetic unit 12, D
The / A converter 15 and the multiplier 16 constitute a rotational moment measuring unit 25. Also, the absolute value processor 20
The excitation stop unit 26 is constituted by the comparator 21 and the excitation stop unit 26.

Next, the operation of the vibration table rotational moment protection device of this embodiment will be described. During the vibration test, the specimen 2
A predetermined vibration is applied to the vibrating table 1 on which is mounted by the vibrator 1A. The test table 2 is placed on the shaking table 1, and the vibration table 1 and the test sample 2 are moved in the horizontal direction by vibrating due to displacement of the center axis between the test sample 2 and the shaking table 1. May rotate. The rotation of the shaking table 1 is detected by the acceleration detectors 5 and 6. That is, when the shaking table 1 rotates, the non-zero value X1 ″ is obtained from the subtractor 7.
−X2 ″ is output.
In 0, the moment of inertia of the vibration table 1 and specimen 2 input from the direct external I _A and either one moment of inertia I of the calculated by the calculation moment of inertia I _B
Given as However, the moment of inertia is calculated by the calculation is given by ^{_{I B = I s + r 2}} · M s + I T.
(Here, I _s is the moment of inertia of the specimen, the M _s mass of the specimen 2, the I _T is the moment of inertia of the vibrating table 1.)

In the multiplier 16, the rotational moment I × (X
1 "-X2") / (2R) is calculated. This rotational moment is output as a rotational moment signal T for monitoring the operating condition, and is also supplied to the absolute value processor 20. Since the rotational moment has a sign corresponding to the direction of rotation, the absolute value processor 20 converts the rotational moment into an absolute value. Then, in the comparator 21, the magnitude of the rotational moment is compared with a predetermined allowable value. The rotational moment alarm value T _{ALAR M} is input to the comparator 21, and an alarm is generated when the rotational moment exceeds the alarm value T _ALARM . Further, when the allowable rotation moment value T _ABORT is exceeded, a vibration stop signal is issued so as to immediately stop the vibration, and the vibrator is stopped.

As described above, in the shaking table rotational moment protection device of the present embodiment, when the rotational moment of the shaking table 1 and the specimen 2 exceeds a predetermined value, an alarm is generated and the excitation is stopped. For this reason, danger due to the generation of a rotational moment can be prevented. Further, since a hydrostatic bearing type guide for suppressing generation of a rotational moment is not required, space can be saved, and contamination due to hydrostatic bearing oil does not occur.

The acceleration detectors 5 and 6 need not always be provided at symmetrical positions from the center of the shaking table 1. Any position can be used as long as the rotational moment can be measured.

[0015]

As described above, the shaking table rotational moment protection device of the present invention does not require a bearing-type guide for suppressing the rotational moment, so that the installation space can be reduced, and the construction and construction can be reduced. Maintenance costs can be reduced, and cost reductions can be realized.

[Brief description of the drawings]

FIG. 1 is a schematic plan view of a shaking table rotational moment protection device shown as one embodiment of the present invention.

FIG. 2 is an overall perspective view showing the appearance of a shaking table.

FIG. 3 is a block diagram of the vibration table rotational moment protection device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Shaking table 1A Exciter 2 Specimen 5, 6 Acceleration detector 7 Subtractor 10 Inertia moment input part 11 Switching means 12 Computing unit 15 D / A converter 16 Multiplier 20 Absolute value processor 21 Comparator 25 Rotation moment measurement Part 26 Excitation stop part

Claims (2)

[Claims] 1. A shaking table on which a specimen is placed, a rotating moment measuring unit for measuring a rotating moment of the shaking table,
A vibration stop unit for receiving an output of the rotation moment measurement unit and performing control to stop the vibration when the rotation moment of the vibration table exceeds an allowable range. Rotational moment protection device. 2. The shaking table rotational moment protection device according to claim 1, wherein the rotating moment measuring unit detects a pair of acceleration detectors provided on the shaking table, and a moment of inertia of the shaking table and the specimen. A moment of inertia input unit for inputting, and calculating a rotational moment based on the acceleration detected by the acceleration detector and the moment of inertia of the vibrating table and the specimen. Protection device.