JP3235820B2 - Small vibration exciter for long-period structures - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION Many structures having a natural period of several seconds, such as skyscrapers, long bridges, and seismic isolation structures, are being constructed. Many of these structures are constructed using new technologies that have not been experienced before. Forcibly exciting the structure at the time of completion and confirming the vibration characteristics of the structure is not enough for the entire structure. It is important to confirm the safety of In addition, since these data will be used as design data in the future, it is desired that the data be implemented in as many structures as possible.

In order to vibrate such a structure, it is necessary to increase the amplitude of the vibration mode (the portion where the vibration amplitude increases when the entire structure vibrates, the antinode of the vibration mode, the skyscraper building). In this case, a vibration exciter (vibrator) shall be installed on the top floor, in the case of a seismic isolation structure, on the floor above the seismic isolation layer, and in the case of a bridge, in the center).

[0003] The present invention is intended to apply a large exciting force to a long-period structure with a machine as small as possible. The size of the machine is such that it can be carried by a general cargo elevator used in high-rise buildings, etc., so that it can be carried in, installed, and removed without using special transport equipment.

[0004]

2. Description of the Related Art In general, a method of applying a vibrating force to a structure is to move a heavy object on the structure and use its inertia force. In order to accurately determine the vibration characteristics of a structure, it is necessary to vibrate the structure with an accurate frequency and a constant excitation force for a certain period of time. It is necessary to excite the structure and accurately measure the change in the response of the building.

[0005] In the prior art, two weights are generally inverted by an electric motor to generate a sinusoidal excitation force in one direction. This is because the control of the motor is relatively easy and it is mechanically simple.

[0006]

The exciting force generated by the exciter can be expressed by the following relational expression.

F = mrω ² (1) where F is the excitation force m is the mass of the weight m = W / g W is the weight of the weight, and g is the gravitational acceleration (9.8
m / S ² ) r is the radius of rotation of the weight or the drive amplitude (single amplitude) of the weight ω ² = (2πf) ² ; f is the frequency (Hz) Wxr is called the excitation moment It can be seen that if the rotation radius of the mass and the weight is the same, the excitation force becomes very small at a long period (low frequency). In the rotary type, there is a limit to an increase in the mass of the weight and an increase in the radius of rotation, and when these are increased, the mechanical portion becomes large, and it is difficult to carry and install the device on a structure, which is not practical.

An object of the present invention is to solve the above problem by moving the weight one-dimensionally on a rail instead of a rotary type.
In this case, r and m are set to be as large as possible so that a large excitation force can be obtained in a long-period excitation.

[0009]

According to the present invention, a movable weight which is moved left and right by a ball screw is installed so as to straddle the ball screw, and the length of the weight driving mechanism is defined as the weight displacement amplitude length. The ball screw is driven to rotate by an AC servomotor, and the rotation speed is fed back to control the vibration frequency and the vibration force.

Further, according to the present invention, the movable weight is composed of divided adjustment weights.

According to the present invention, the AC servomotor and the ball screw driven by the motor are provided on a carriage provided with a moving caster and a leveling block.
The movable weight moved to the left and right by the ball screw is moved by a rail provided on the bogie and a roller bearing.

According to the present invention, the movable weight is provided with an accelerometer, and the bogie is provided with a position detecting scale.

According to the present invention, the operation of the vibration exciter is performed by electric control. Further, according to the present invention, two exciters having the same function can be linked with each other to perform the synchronous operation and the opposite phase operation of the two exciters.

As a method of moving the weight at a stable frequency and a constant amplitude in one direction, a method using a hydraulic actuator or a method combining an electric motor with a crank mechanism can be considered. Can not be planned,
A mechanism using a ball screw is adopted. Since the movable weight is installed so as to straddle the ball screw, the length of the weight drive mechanism can be used as the weight displacement amplitude length, and the size can be reduced. Also, by using an AC servomotor as a drive motor and feeding back the position, speed, and torque of the weight, high-precision excitation frequency and excitation force control can be performed.

Since all of these controls can be performed electrically,
If another exciter having the same function is prepared, two synchronous operation and anti-phase operation can be performed, and a larger exciting force or a torsional moment can be applied to the structure.

In implementation, the movable weight is composed of a divided adjustment weight, and the AC servomotor and the ball screw driven by the motor are provided on a carriage provided with a moving caster and a leveling block. In addition, the movable weight that is moved left and right by the ball screw is to be moved by a rail provided on the bogie and a rolling support. Further, an accelerometer is provided on the movable weight, and a scale for position detection is provided on the bogie.

Compared to the conventional rotary type exciter that can be carried by a cargo elevator, the exciter of the present invention has a capacity of 0.4H.
A 10-fold excitation force can be obtained at a low frequency of z or less. Since the operation of the vibration exciter is performed by the electric control as described above, the data can be digitally controlled and can be controlled from a distant place. In conventional machines, in the case of a vibration test of a high-rise building, the exciter had to be installed on the top floor and operated near the exciter, but with the exciter of the present invention, vibration near the ground was required. It can be operated near a measuring instrument (in a vibration measuring car).

[0018]

1 to 3, there is provided a movable weight 2 which is moved left and right by a ball screw 1. The weight 2 is installed so as to straddle the ball screw 1. The length of the mechanism is the weight displacement amplitude length. AC as a motor for rotating the ball screw 1
The servo motor 5 is used.

The vibration exciter having the above configuration is provided on a carriage 6 provided with a moving caster 7 and a leveling block 8 also serving as a floor fixing jig, and the weight 2 is provided on a rail 9 provided on the carriage 6. And the roller bearing 10 on the side of the weight 2 make it possible to move with less friction.
The cart 6 is provided with a scale 11 for position detection, and the movable weight 2 is provided with an accelerometer 12.

The movable weight 2 is composed of a moving body 3 screwed to the ball screw 1 and a divided adjusting weight 4 mounted and fixed on the moving body 3, and the adjusting weight 4 is completely mounted. so,
This weight has a weight of 2 tons (W) and the left and right movement is ± 5
It moves (r) by 0 cm.

In other figures, 13 is a limit switch, 14 is a magnetic sensor, 15 is a shock absorber for adjustment, 16 is a movable case for protecting a measurement cable, and 17 is a cover of a ball screw.

As described above, the AC servomotor 5 is used as a drive motor for the ball screw 1 and the speed is fed back to control the vibration frequency and the vibration force with high precision.

At the time of implementation, the machine is transported in a divided state to some extent, so that the machine can be assembled by a simple operation. 183 maximum outer shape of transport parts
cm x 90 cm x 60 cm (height) and maximum weight is 1 ton or less.

The weight of the movable part is the weight for adjustment as described above. For example, the weight is made by stacking iron plates, and the excitation force can be adjusted by adjusting the number of iron plates. To

Further, as also by changing the variation of the frequency of the electric control is Aruomega ² of Expression 1 becomes constant r
(Amplitude value) so that a vibration experiment with a constant vibration force can be performed.

Since the excitation frequency and the excitation force of the exciter can all be controlled electrically, when two units having the same function are linked to each other, A double excitation force can be obtained, and a torsional moment can be given to the structure when the phases of the two units are reversed. At this time, it is important to control the phases of the two exciters,
If the phase difference between the two vibrators is in phase within the operating frequency range (0.1 Hz to 5 Hz), this should be 0 degrees ± 2 degrees or less,
In the case of the opposite phase, the angle is set to 180 ° ± 2 ° or less.

FIG. 4 shows a case where two exciters having the same function are used in conjunction with each other. In the case of a high-rise building, the first vibration exciter 20A and the second vibration exciter 20B are installed at a position A near the top floor, the machine-side control panels 21A and 21B are provided, respectively, and near the ground (in a vibration measuring vehicle). The master control panel 23A and the handy terminal 24A are provided at the vibration measurement position B of FIG. The handy terminal 24A has a frequency and an exciting force of 2
The same and opposite phases of the two exciters 20A and 20B can be input. In the figure, the dotted line (a) shows the case where two units are linked, and when the solid line (b) is not linked, they can be used as separate exciters. If the handy terminals 22A and 22B are connected to the machine-side control panels 21A and 21B, respectively, it is possible to operate while looking at the machine near the exciter.

FIG. 5 is a control block diagram of the exciter. The speed command value set by the function generator F1, which is the amplitude / frequency setting means of the machine side control panel 21A, is transmitted to the servo amplifier A, and the excitation current i
Is output to the coil 5a of the AC servomotor 5. Here, the output value of the exciting current i is fed back to the servo amplifier A and controlled. The motor body and the load inertia 5b are rotated at a rotational speed dθ / dt by the torque τ generated by the exciting current i. Here, the rotation speed is detected and fed back to the servo amplifier A. Then, the rotation of the motor 5 is transmitted to the ball screw 1 which is the drive shaft coordinate conversion means, and the displacement X in the left-right direction is transmitted.
Is converted and output. The displacement X is detected by a displacement meter K as a maximum value / minimum value detecting means, fed back to an origin deviation correcting offset value determining means H, and transmitted to a servo amplifier A.

When the two exciters 20A and 20B are operated in an interlocked manner, command signals are exchanged by connecting the function generators F1 and F2 together. That is, as shown by the broken line in the figure, when the first vibration exciter 20A is the master, the first function generator F1 outputs the second function for the second vibration exciter 20B as shown by the broken line indicated by the symbol M. A signal is output to generator F2. When the first vibration exciter 20A is a slave, the second function generator F2
The signal is bypass-outputted to the first function generator F1 by only performing a phase operation.

Next, the procedure for assembling the vibration generator will be described with reference to FIGS. Using the casters 7 attached to the lower part of the cart 6, the carry-in is performed manually (FIG. 6). At the vibration position, the level is adjusted by the leveling blocks 8 installed at three places on one side and six places on both sides (FIG. 7), and after the level is adjusted, the bolts are fixed to the floor.

The servomotor 5 is lifted using the lifter 18 and attached (FIG. 8). The divided adjustment weight 4 is manually attached (FIG. 9). Attach the safety protection cover 19 (FIG. 10).

FIG. 11 shows a performance curve of the apparatus according to the present invention in comparison with a conventional rotary vibration exciter. In the state where the weight is maximized, a maximum excitation moment A of 1000 kg · m can be obtained. did. This is 10 times as large as that of a rotary type vibration exciter of the same size with a maximum excitation moment B of 100 kg · m.

[0033]

According to the present invention, it is possible to apply a large exciting force to a long-period structure with a small machine. The size of the machine is such that it can be carried by a general cargo elevator used in high-rise buildings, etc., and can be carried in, installed, and removed without using special transport machines.

[Brief description of the drawings]

FIG. 1 is a side view of an exciter according to an embodiment of the present invention.

FIG. 2 is a plan view of FIG. 1;

FIG. 3 is a front view of FIG. 1;

FIG. 4 is a system diagram in which two vibration exciters having the same function are linked.

FIG. 5 is a control block diagram of the exciter according to the present invention.

FIG. 6 is a frame loading diagram showing an assembling procedure of the vibration exciter.

FIG. 7 is a level adjustment diagram of FIG. 5;

FIG. 8 is a view showing the mounting of the servo motor of FIG. 5;

FIG. 9 is a diagram of the weight attached to FIG. 5;

FIG. 10 is a view showing the installation of the protective cover in FIG. 5;

FIG. 11 is a performance curve diagram of the vibration exciter of the present invention as compared with a conventional rotary vibration exciter.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Ball screw 2 ... Movable weight 3 ... Moving body 4 ... Adjusting weight 5 ... AC servomotor 6 ... Cart 7 ... Caster 8 ... Leveling block 9.・ ・ Rail 10 ・ ・ ・ Colouring bearing 11 ・ ・ ・ Position detecting scale 12 ・ ・ ・ Accelerometer 13 ・ ・ ・ Limit switch 14 ・ ・ ・ Magnetic sensor

Continued on the front page (72) Inventor Hidetoshi Nagao 1-6-1, Minamidai, Kawagoe-shi, Saitama Kaji Mamechatro Engineering Co., Ltd. Kawagoe Works (72) Inventor Katsura Ogasawara 1-6-1, Minamidai, Kawagoe-shi, Saitama No. Kaji Mamechatro Engineering Co., Ltd. Kawagoe Works (72) Inventor Shigeru Mutaguchi 1-6-1, Minamidai, Kawagoe-shi, Saitama Prefecture Kaji Mamechatro Engineering Co., Ltd. Kawagoe Works (56) References JP-A-7-4114 ( JP, A) JP-A-2-300478 (JP, A) JP-A-4-254677 (JP, A) JP-A-2-156129 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , (DB name) G01M 7/02 E04H 9/02 341

Claims (6)

(57) [Claims] A movable weight which is moved left and right by a ball screw is installed so as to straddle the ball screw, the length of the weight driving mechanism is set to the weight displacement amplitude length, and the ball screw is rotated by an AC servomotor. A small-sized vibrator for exciting a long-period structure, which is driven and controls its excitation frequency and excitation force by feeding back its rotation speed. 2. The small-sized vibrator according to claim 1, wherein the movable weight is composed of divided adjustment weights. 3. An AC servomotor and a ball screw driven by the motor are provided on a carriage provided with a moving caster and a leveling block, and a movable weight moved left and right by the ball screw is provided with a rail provided on the carriage and a roller. 3. The small-sized vibrator for exciting a long-period structure according to claim 1, wherein the small-sized vibrator is moved by a bearing. 4. The small-sized vibrator for exciting a long-period structure according to claim 3, wherein the movable weight is provided with an accelerometer, and the bogie is provided with a position detecting scale. 5. The small-sized vibrator for exciting a long-period structure according to claim 1, wherein the operation of the vibrator is performed by electric control. 6. A small-sized vibrator for exciting a long-period structure according to claim 5, wherein two exciters having the same function are linked to perform synchronous operation and anti-phase operation of the two exciters. Shaker.