JP4208651B2 - Vibration table device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vibration table device suitable for various vibration tests such as a test for investigating the influence of an earthquake on a structure.
[0002]
[Prior art and its problems]
Conventionally, the vibration table device has been used as a vibration test device in various fields, and has a structure in which, for example, a table supported so as to be able to reciprocate in the horizontal direction is driven in the reciprocating direction by various actuators.
[0003]
The actuator for reciprocating the table includes a hydraulic type using a hydraulic cylinder, a mechanical type having a differential device such as a gear / crank, and an electrodynamic type using an electromagnetic force generated by a magnetic force generator such as an exciting coil (for example, Patent Document 1) has been put to practical use.
[0004]
In an apparatus including the actuator as described above, a complicated mechanical structure is required to accurately reproduce high-frequency vibration, which causes a problem that the apparatus cost increases and maintenance is difficult.
[0005]
By the way, if a pneumatic cylinder is used for the actuator, there is an advantage that the structure of the apparatus can be simplified, the apparatus cost can be reduced, and the maintenance can be facilitated.
[0006]
However, since air is a highly compressible fluid, a phase difference is likely to occur between the target value of the vibration to be applied to the specimen placed on the table and the vibration that actually occurs. It is considered that a pneumatic actuator such as a pneumatic cylinder is difficult to apply to a vibration table device.
[0007]
[Patent Literature]
[Patent Document 1]
JP 2000-146748 (Page 5-6 and FIG. 8)
[0008]
【the purpose】
The object of the present invention is that a phase difference between the target value of vibration and the actual vibration is less likely to occur, higher reproducibility is easily obtained, and the structure is simple and the apparatus cost can be reduced. It is another object of the present invention to provide a pneumatic vibration table device that is easy.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, a vibration table device according to claim 1 of the present invention comprises a table supported on a base so as to reciprocate on a horizontal straight line, and two pneumatic pressures for reciprocating the table. A cylinder and an air supply system that alternately supplies compressed air to the pneumatic cylinders according to a required frequency based on a signal from a control device, and the pneumatic cylinders are single-acting These pneumatic cylinders are arranged on the base so that the rods face each other in the reciprocating direction of the table, and the rods are connected to the table. A compression coil spring is provided between the piston and the front wall through which the rod passes in the accommodated cylinder body, and each of the two pneumatic cylinders is compressed by the compression coil spring. It has been arranged on the base such that the state, the rod of the pneumatic cylinder is energized in a state where attracted to each other by the spring force of the compression coil spring, exact by inquiries of the compression coil spring damping effect during the initial positioning and operation of the rod is configured so as to obtain, and the air distance between the pressure cylinder, the arrangement configured to so that can be adjusted to suit the size of the amplitude to try to generate As a thing.
[0010]
Further, the vibration table device according to claim 2 of the present invention is based on the displacement feedback signal from the displacement detector that detects the displacement accompanying the reciprocation of the table and the target waveform signal from the waveform transmitter. A pneumatic servo controller that outputs a control signal to a pneumatic servo valve that controls the supply of compressed air to the cylinder is provided .
[0011]
【Example】
Hereinafter, embodiments of a vibration table device according to the present invention will be described in detail based on specific examples shown in the accompanying drawings.
(Overall outline)
The pneumatic vibration table device according to the present invention includes a device main body 1 on which a specimen is placed, an air supply system device 2 that supplies air to the device main body 1, and a control device 3 that controls vibration.
[0012]
The apparatus body 1 supports a table 6 so as to be reciprocally movable in a horizontal direction via a support mechanism 5 provided on the base 4, and provides a driving force in the reciprocating direction with respect to the table 6 on the base 4. Two pneumatic cylinders 7 and 7 are provided.
More specifically, rods 7a and 7a of the pneumatic cylinders 7 and 7 are provided on the left and right sides of the center web 8 that supports the table from below, and the tips of the rods are connected via universal joints 9 and 9, respectively. Attached to the center web.
The details of the pneumatic cylinder will be described later.
[0013]
On the base 4, a pneumatic servo valve 10 that supplies air to the pneumatic cylinders 7 and 7 and opens and closes at a set frequency, and a displacement detector 11 that detects displacement associated with the reciprocation of the table 6 are provided. Is provided.
[0014]
The air supply system device 2 is provided separately from the device body 1 and supplies compressed air to the pneumatic servo valve 10 of the device body.
The control device 3 is configured to control the air servo valve 10 based on a detection signal from the displacement detector 11 in the device body 1.
[0015]
(Support mechanism 5)
Base webs 12 and 12 are erected on the front and rear sides of the base plate 4 having a substantially rectangular shape along the table moving direction, and a guide rail 13 parallel to the web is horizontally provided on each base web. Is provided.
[0016]
Carriages 14 and 14 fixed to the lower surface of the table 6 are slidably attached to the guide rails 13 and 13, and the table is extremely loaded with respect to the guide rails 13 and 13 even under load and moment load. Stop gears 13a and 13a for restricting the movement of the carriage are provided at both ends of the guide rail.
For the guide rail and the carriage, for example, a linear bearing (orbital ball bearing) is used.
[0017]
Further, end plates 15 and 15 are provided between the left and right end portions of the base webs 12 and 12, respectively, and stoppers 16 and 16 for restricting the reciprocating amplitude of the table 6 are provided on each end plate. This stopper is equipped with a buffering piston and the tip rod is designed to absorb shocks. The buffering piston can absorb a large amount of energy while allowing a small displacement. When an excessive amplitude occurs, the tip contacts the stop plates 17 and 17 provided on the lower surface of the table, so that the excessive amplitude of the table can be regulated safely.
[0018]
(Pneumatic cylinder 7)
As shown in FIG. 4, each of the pneumatic cylinders 7 and 7 is composed of a single-acting bellow frame cylinder in which the inside of the cylinder body 18 is partitioned into two chambers by a bellow frame 19 and a piston 20. A compression coil spring 22 is provided in the front chamber 18A between the piston and the front wall 21 on the rod protruding side to urge the piston in the direction in which the rod is contracted, and the rod slides around the rod 7a. A ball bearing 34 for interposing a very small friction is interposed.
[0019]
When compressed air is supplied from the air supply port 18a into the rear chamber 18B between the rear wall 23 and the piston 20 that closes the rear end of the cylinder body 18, the pneumatic cylinders 7 and 7 It is moved to the front chamber side against the spring force of the compression coil spring 22, the air in the front chamber is discharged to the outside from the communication port 18b, and the rod protrudes from the cylinder body as the piston moves (extension of the rod). Operation).
[0020]
When the pressure of air supplied into the rear chamber 18B is reduced, the piston 20 is pushed back to the rear chamber side by the spring force of the coil spring 22, and outside air is introduced into the front chamber from the communication port 18b. With the movement of the rod, the rod is pulled into the cylinder body (rod contraction operation).
[0021]
The expansion and contraction of the rod acts in the opposite manner in the left and right pneumatic cylinders, that is, when compressed air is supplied to one pneumatic cylinder and the rod extends, the other pneumatic cylinder Compressed air is not supplied and contraction is performed.
[0022]
Thus, the compression coil springs 22 and 22 in the left and right pneumatic cylinders 7 and 7 are both compressed against the spring force when no compressed air is supplied to any of the left and right pneumatic cylinders. The spring force can be arbitrarily set by adjusting the mounting position of the pneumatic cylinder with respect to the base plate 4. Specifically, the pneumatic cylinder is attached to the base plate. The mounting position of the cylinder holder 33 for fixing the cylinder can be arbitrarily set in the rod expansion / contraction direction.
[0023]
Then, when the amplitude of the vibration to be generated is large, the distance between the two cylinders is set to be large, and when the amplitude is small, the two cylinders are set close to each other, This can be done so that the amount of compressed air supplied to the cylinder can be reduced. In this case, naturally, the responsiveness leading to the improvement of the frequency characteristics is also good.
[0024]
If one return cylinder is used instead of two single acting cylinders, a long stroke must always be used in accordance with the maximum amplitude of vibration to be generated. When this vibration is generated, the amount of air to be supplied to the cylinder becomes large, which is inefficient and responsiveness is impaired.
[0025]
In addition, the initial position of the table is always held at a predetermined position by the spring force of the compression coil springs in the left and right pneumatic cylinders, and there is a great merit that the initial position can be easily set, and a damping effect can be obtained. You can also.
[0026]
(Pneumatic servo valve 10)
The pneumatic servo valve 10 controls the supply of compressed air to the pneumatic cylinders 7 and 7 by opening and closing the valve based on a set frequency. This valve opening and closing is controlled by a control signal from the control device 3. Done.
When the valve is closed, the compressed air in the pneumatic cylinder is exhausted from the muffler 10a.
[0027]
(Displacement detector 11)
In the displacement detector 11, the tip of the probe rod 11a is connected to the center web 8 of the table 6 via a connecting member 24, detects the displacement accompanying the reciprocating motion of the table 6, and based on the detected displacement value. The displacement signal is sent to the control device 3 as a feedback value.
[0028]
(Air supply system 2)
The air supply system device 2 includes a compressor 25, an air filter 26, an air adjustment valve 27, a three-way valve 28 and an air supply pipe 29, and supplies compressed air to the pneumatic servo valve 10.
[0029]
(Control device 3)
The control device 3 is provided separately from the device main body 1 and the air supply system device 2, and includes a displacement amplifier 30 that amplifies a displacement signal from the displacement detector 11, and a waveform that outputs a target waveform signal. An oscillator 31 and a pneumatic servo controller 32 that outputs a control signal to the pneumatic servo valve 10 based on the displacement feedback signal and the target waveform signal are provided.
[0030]
【The invention's effect】
As described above, according to the present invention, since two single-acting pneumatic cylinders mounted opposite to each other are used, the stability of the left-right symmetric stability is improved compared to the case of using one backward-acting pneumatic cylinder. The reciprocating mechanism is constructed with a simple structure, and the number of bellows that are used inside can be halved (in the case of a return-acting pneumatic cylinder, four are required per unit), and the drive friction is reduced accordingly. Therefore, the effect of suppressing the phase difference between the target waveform of vibration to be controlled and the feedback waveform obtained as a result of the control is increased, and thus higher reproducibility can be achieved. it can.
[0031]
In addition, the single-acting pneumatic cylinders are arranged in a state where the compression coil springs in each cylinder are compressed, so it has excellent damping effect when returning to the initial position during non-control and during driving. The phenomenon can be suppressed and the phase difference is less likely to occur, and high safety and reproducibility can be obtained.
[0032]
Furthermore, since air is used as the power source, there is a self-cooling action, and it is not necessary to provide a separate heat dissipating means, so that the cost of the apparatus can be reduced, and there is a great merit that it is clean and easy to maintain. I have prepared myself.
[Brief description of the drawings]
FIG. 1 is an overall schematic view showing an embodiment of a pneumatic vibration table device according to the present invention.
FIG. 2 is a plan view showing a state where a table of the apparatus main body is removed.
FIG. 3 is a longitudinal front view of the apparatus main body.
FIG. 4 is a longitudinal sectional view of a pneumatic cylinder.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Apparatus main body 2 Air supply system apparatus 3 Control apparatus 4 Base 5 Support mechanism 6 Table 7 Pneumatic cylinder 8 Center web 9 Universal joint 10 Pneumatic servo valve 11 Displacement detector 12 Base web 13 Guide rail 14 Carriage 15 End plate 16 Stopper 17 Stop plate 18 Cylinder body 19 Bellow frame 20 Piston 21 Front wall 22 Compression coil spring 23 Rear wall 24 Connecting member 25 Compressor 26 Air filter 27 Air control valve 28 Three-way valve 29 Air supply pipe 30 Displacement amplifier 31 Waveform oscillator 31 Pneumatic servo control 33 Cylinder holder 34 Ball bearing

Claims (2)

A table supported on the base so as to reciprocate on a horizontal straight line, two pneumatic cylinders for reciprocating the table, and compressed air required for each pneumatic cylinder based on a signal from the controller Each of the pneumatic cylinders is composed of a single-action bellow-flam cylinder, and these pneumatic cylinders are arranged in the reciprocating direction of the table. The pneumatic cylinder is arranged between the front wall through which the rod passes in the cylinder body in which the piston passes and the piston, and is arranged on the base so that the rods face each other and is connected to the table. And two pneumatic cylinders are arranged on the base so that the respective compression coil springs are compressed, and each pneumatic cylinder Rod is urged in a state of attract each each other by the spring force of the compression coil spring, the inquiries of the compression coil spring is configured as a damping effect during the initial positioning and operation of the exact rod is obtained, and the the distance between the pneumatic cylinder, formed by configured so that can be adjusted to suit the size of the amplitude to try to generate the vibration table system. A pneumatic servo valve that controls the supply of compressed air to the pneumatic cylinder based on a displacement feedback signal from a displacement detector that detects displacement accompanying reciprocation of the table and a target waveform signal from a waveform transmitter. The vibration table device according to claim 1, further comprising a pneumatic servo controller that outputs a control signal .

Images