JP3981789B2 - 2-axis seismic isolation rubber testing machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a biaxial seismic isolation rubber testing machine used for investigation of spring characteristics of seismic isolation rubber.
[0002]
[Prior art]
A biaxial seismic isolation rubber testing machine is known as a testing machine for investigating or evaluating the spring characteristics of seismic isolation rubber. In general, a biaxial seismic isolation rubber testing machine includes a vertical load cylinder and a horizontal load cylinder that are driven and controlled by a hydraulic servomechanism using a servo valve. With a movable lower platen, with the test seismic isolation rubber sandwiched between the upper platen and the lower platen, a vertical load cylinder applies a certain compressive load to the base isolation rubber via the upper platen while applying a horizontal load. A load is repeatedly applied to the lower surface of the base isolation rubber through the lower pressure plate by the cylinder for measuring, and the horizontal load-horizontal displacement characteristics as illustrated in FIG. 3 are measured, and the spring characteristics in the horizontal direction of the base isolation rubber are investigated.
[0003]
[Problems to be solved by the invention]
By the way, in recent years, there has been a tendency to increase the demand for testing the spring characteristics at high speeds of the seismic isolation rubber. Although the vertical load cylinder is controlled so that the vertical load is constant by the mechanism, there is a problem that the vertical load fluctuates in accordance with the period of the horizontal load.
[0004]
That is, as schematically shown in FIG. 4, with the seismic isolation rubber W sandwiched between the upper platen 41 and the lower platen 42, a certain compressive load is applied via the upper platen 41, and the lower platen 42 If a load is applied in the horizontal direction, the height of the seismic isolation rubber W decreases by δV. Due to the change in the height of the seismic isolation rubber W, the compressive load in the vertical direction varies. At this time, the hydraulic servomechanism for driving and controlling the vertical load cylinder for applying the compressive load in the vertical direction operates to adjust the valve opening of the servo valve so as to suppress the fluctuation of the load. When the repetition rate of the load in the horizontal direction is slow, the vertical load is kept constant as shown in the graph of FIG. 5A, but the repetition rate of the horizontal load exceeds the response speed of the servo valve. If the servo valve capacity is insufficient to cope with the above load fluctuation, the required pressure oil is not supplied to the vertical load cylinder, as illustrated in FIG. 5B. The compression load in the vertical direction fluctuates in synchronization with the repeated load in the horizontal direction.
[0005]
In order to solve this problem, it is necessary to increase the response and capacity of the servo valve that drives the cylinder for the vertical load, which not only causes an increase in cost, but also has a limit in the horizontal direction. If the repeated load speed is further increased, it becomes difficult to keep the compressive load in the vertical direction constant.
[0006]
The present invention has been made in view of such circumstances, and even if the repetition rate of the horizontal load is increased without increasing the response and capacity of the servo valve that drives the vertical load cylinder, The purpose is to provide a two-axis seismic isolation rubber testing machine that can maintain a constant compressive load.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, a biaxial seismic isolation rubber testing machine according to the present invention includes a vertical load cylinder and a horizontal load cylinder, each of which is driven and controlled by a hydraulic servomechanism. In the biaxial seismic isolation rubber testing machine, which applies a constant compression load in the vertical direction to the test isolation rubber, and repeatedly applies a horizontal load to investigate the horizontal spring characteristics of the isolation rubber, It is characterized by being configured so that an accumulator can be selectively connected to a compression side port of the vertical load cylinder via an electromagnetic valve.
[0008]
By connecting an accumulator to the compression side port of the vertical load cylinder at the time of the test, the present invention supplies pressure oil corresponding to the change in the height of the seismic isolation rubber due to repeated load in the horizontal direction. By supplying the cylinder from the accumulator to the vertical load cylinder without going through the servo valve, the intended purpose is achieved.
[0009]
That is, when a constant compression load is applied to the seismic isolation rubber in a vertical direction and a horizontal load is repeatedly applied, the height of the seismic isolation rubber changes in synchronization with the repetition cycle. When the pressure decreases, the piston of the vertical load cylinder moves downward. At this time, if the response of the servo valve is delayed and pressure oil is not supplied, the compression load in the vertical direction is reduced as in the conventional case. In the present invention, however, it is connected to the compression side port of the vertical load cylinder. As a result, the pressure oil is supplied from the accumulator to the vertical load cylinder even if the pressure oil is not supplied via the servo valve when the piston of the vertical load cylinder moves downward. As long as the capacity of the accumulator is appropriately selected, the compression load in the vertical direction hardly fluctuates.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a front view showing a mechanical configuration of an embodiment of the present invention.
An upper platen 3 is slidably supported on a frame 1 having a generally rectangular shape via a plurality of vertical linear guide bearings 2, and a lower platen is provided below the plurality of horizontal linear guide bearings 4. 5 is slidably supported. A load in the vertical direction is applied to the upper platen 3 by a vertical load cylinder 6 attached to the upper portion of the frame 1, while a horizontal load attached to the side of the frame 1 is applied to the lower platen 5. A load in the horizontal direction is applied by the cylinder 7.
[0011]
The seismic isolation rubber W is used for the test in a state of being sandwiched between the upper platen 3 and the lower platen 5, and the vertical and horizontal loads acting on the seismic isolation rubber W are respectively applied to the vertical load cell 8 and the horizontal load. The displacement (deformation) in the vertical direction and the horizontal direction of the seismic isolation rubber W is detected by the load cell 9 and is detected by the stroke detector built in each of the vertical load cylinder 6 and the horizontal load cylinder 7. The
[0012]
The vertical load cylinder 6 and the horizontal load cylinder 7 are controlled by a hydraulic servo mechanism provided corresponding to each. That is, the vertical load cylinder 6 and the horizontal load cylinder 7 are respectively supplied with pressure oil from a hydraulic power source via a dedicated servo valve, and each servo valve in the vertical load cylinder 6 is a vertical load cell. With the output of 8 as the detection value and the horizontal load cylinder 7 with the output of the built-in stroke detector or horizontal load cell 9 as the detection value, each detection value matches each preset target value. Each valve opening is controlled. In examining the horizontal spring characteristics, the vertical load cylinder 6 is driven and controlled so that a constant compressive load in the vertical direction acts on the test seismic isolation rubber W, and the horizontal load cylinder 7 is The drive control is performed so that a horizontal load is repeatedly applied to the trial seismic isolation rubber W.
[0013]
The feature of this embodiment lies in a hydraulic circuit for driving the vertical load cylinder 6, and FIG. 2 shows a hydraulic circuit diagram thereof.
The vertical load cylinder 6 is operated by the pressure oil supplied from the hydraulic pressure source through the pressure line 14a via the servo valve 10 as described above. The compression side port 6a of the vertical load cylinder 6 and the servo valve are operated. 10, an accumulator 12 is connected via an electromagnetic direction control valve 11. An electromagnetic direction control valve 13 is also inserted between the pulling side port 6b of the vertical load cylinder 6 and the servo valve 10, and these electromagnetic direction control valves 11 and 13 are driven and controlled in synchronization with each other. When the seismic isolation rubber W is attached before the test is started, the solenoids are turned off as shown in FIG. 2, and the solenoids are turned on at the time of the test.
[0014]
In the above circuit configuration, when the electromagnetic directional control valves 11 and 13 are in the state shown in FIG. 2, the accumulator 12 is disconnected from the compression side port 6a of the vertical load cylinder 6 and connected to the return line 14b. In addition, the tension side port 6b is directly connected to the servo valve 10. In this state, the vertical load cylinder 6 is directly moved by the operation of the servo valve 10, and the seismic isolation rubber W can be attached by the same operation as in the prior art.
[0015]
When the solenoids of the electromagnetic control valves 11 and 13 are turned on from the state shown in FIG. 2, the accumulator 10 is connected between the compression side port 6a of the vertical load cylinder 6 and the servo valve 10, and the tension is applied. The side port 6b bypasses the servo valve 10 and is connected to the return line 14b. When the servo valve 10 is driven in this state and the pressure line 14a is connected to the compression side port 6a of the vertical load cylinder 6, the vertical load cylinder 6 operates to apply a compression load to the test seismic isolation rubber W. At the same time, the pressure oil is supplied to the accumulator 12 and accumulated. The valve opening of the servo valve 10 is controlled by the operation of the servo mechanism, and the horizontal load cylinder 7 is driven in the horizontal direction while a constant compression load in the vertical direction is applied to the test seismic isolation rubber W. When the load is repeatedly applied, the seismic isolation rubber W is deformed in synchronism with the repetition period, and the height thereof is changed as described above, and the piston of the vertical load cylinder 6 is displaced. At this time, since the pressure oil stored in the accumulator 12 under the required pressure is supplied to the compression-side port 6a of the vertical load cylinder 6, the vertical load cylinder 6 moves along with the deformation of the test seismic isolation rubber W. Even if the piston is displaced, the internal pressure hardly changes, and the vertical compressive load acting on the test seismic isolation rubber W is kept substantially constant.
[0016]
Accordingly, the speed of the repeated load in the horizontal direction is high and exceeds the response speed of the servo valve 10 or due to the capacity of the servo valve 10 being insufficient, the required amount is applied to the vertical load cylinder 6 via the servo valve 10. Even if the pressure oil is not supplied, the compressive load in the vertical direction of the seismic isolation rubber W does not vary greatly in synchronization with the repeated load in the horizontal direction, and a substantially constant vertical load can be maintained.
[0017]
【The invention's effect】
According to the present invention, the accumulator can be selectively connected to the compression side port of the vertical load cylinder via the solenoid valve, so that a constant compressive load in the vertical direction is applied to the seismic isolation rubber. When performing a spring characteristic test that repeatedly applies a load in the horizontal direction, even if the response speed and capacity of the servo valve that drives the vertical load cylinder cannot cope with it by increasing the horizontal load repetition rate, The fluctuation of the compressive load in the direction can be suppressed, and a low-cost and high-performance biaxial seismic isolation rubber testing machine can be obtained.
[Brief description of the drawings]
FIG. 1 is a front view showing a mechanical configuration of an embodiment of the present invention.
FIG. 2 is a hydraulic circuit diagram for driving the vertical load cylinder 6 according to the embodiment of the present invention.
FIG. 3 is an explanatory diagram of an example of horizontal load-horizontal displacement characteristics of a seismic isolation rubber obtained by a biaxial seismic isolation rubber testing machine.
FIG. 4 is an explanatory diagram of the cause of fluctuations in the vertical compressive load when a horizontal load is repeatedly applied to the seismic isolation rubber while a constant compressive load is applied in the vertical direction.
FIG. 5 is an explanatory diagram of the relationship between a vertical compression load and a horizontal repeat load by a conventional two-axis seismic isolation tester, and (A) shows a case where the horizontal load repeat rate is slow. (B) are graphs showing examples of cases where the speed is high.
[Explanation of symbols]
1 frame 1
2 Vertical linear guide bearing 3 Upper pressure plate 4 Horizontal linear guide bearing 5 Lower pressure plate 6 Vertical load cylinder 6a Compression side port 6b Pull side port 7 Horizontal load cylinder 8 Vertical load cell 9 Horizontal load cell 10 Servo valves 11, 13 Electromagnetic direction control valve 12 Accumulator 14a Pressure line 14b Return line W Seismic isolation rubber

Claims (1)

Each cylinder is equipped with a vertical load cylinder and a horizontal load cylinder that are driven and controlled by a hydraulic servomechanism. By controlling the drive of each cylinder, a constant compression load in the vertical direction is applied to the test seismic isolation rubber. In a biaxial seismic isolation rubber testing machine that investigates horizontal spring characteristics of seismic isolation rubber by applying repeated horizontal loads, an accumulator is selectively connected to the compression side port of the vertical load cylinder via a solenoid valve. A two-axis seismic isolation rubber testing machine characterized by being configured to be able to connect.

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