JP5368084B2 - Vibration test equipment - Google Patents

Description

  In the present invention, a hydraulic cylinder unit is driven by a pump that can be driven in both forward and reverse directions, and a vibration table attached to a piston rod of the hydraulic cylinder unit is reciprocated to vibrate a subject on the vibration table. The present invention relates to a vibration test apparatus.

As a vibration test apparatus that vibrates a subject with a hydraulic cylinder, a device using a fixed displacement pump and a servo valve as in Patent Document 1 is used. Such a vibration test apparatus can vibrate the subject at a high frequency while applying a large load to the subject. An example of a circuit diagram of a hydraulic vibration testing apparatus using a servo valve is shown in FIG.
JP 2000-2617 A

  The hydraulic vibration test apparatus 101 shown in FIG. 5 includes a pump unit 110, a hydraulic oil tank 120, a hydraulic cylinder unit 130, a servo valve 140, and a vibration table 150. A work W is fixed on the vibration table 150, and the work W is vibrated by reciprocating the vibration table 150.

  The pump unit 110 drives a fixed displacement pump main body 111 by a motor 112, and is disposed between the hydraulic oil tank 120 and the servo valve 140. Note that the rotation direction of the motor 112 is one direction, and only normal rotation is possible. Further, the rotational speed of the motor 112 is kept substantially constant. The pump unit 110 has a function of only sending hydraulic oil from the hydraulic oil tank 120 to the servo valve 140, and the flow rate thereof is kept substantially constant.

  The cylinder unit 130 includes a sleeve 131, a piston 132 that can move within the sleeve 131, and a piston rod 133 that projects from one surface of the piston 132 to the outside of the sleeve 131. A vibration table 150 is fixed to the tip of the piston rod 133. The inside of the sleeve 131 is divided into a first pressure chamber 131a and a second pressure chamber 131b by a piston 132. Hydraulic oil is sealed in the first pressure chamber 131a and the second pressure chamber 131b. The first pressure chamber 131a and the second pressure chamber 131b are connected to the servo valve 140 via pipes 161 and 162, respectively.

  The servo valve 140 is used for switching the hydraulic oil sent from the pump unit 110 to which of the pipes 161 and 162 and controlling the hydraulic pressure of the hydraulic oil sent to the pipe. The servo valve 140 connects a pipe through which hydraulic oil is not sent to the hydraulic oil tank 120. The switching operation and hydraulic pressure adjustment operation of the servo valve 140 are controlled by the controller 102.

  When the hydraulic oil sent from the pump unit 110 is sent to the pipe 161, the hydraulic oil is supplied to the first pressure chamber 131a, and the internal pressure of the first pressure chamber 131a increases. Accordingly, the piston 132 is pushed down toward the second pressure chamber 131b, and the vibration table 150 is lowered. At this time, the hydraulic oil in the second pressure chamber 131 b is returned to the hydraulic oil tank 120 via the pipe 162 and the servo valve 140. On the other hand, when the hydraulic oil sent from the pump unit 110 is sent to the pipe 162, the hydraulic oil is supplied to the second pressure chamber 131b, and the internal pressure of the second pressure chamber 131b increases. As a result, the piston 132 is pushed up toward the first pressure chamber 131a, and the vibration table 150 is raised. At this time, the hydraulic oil in the first pressure chamber 131 a is returned to the hydraulic oil tank 120 via the pipe 161 and the servo valve 140.

  As shown in FIG. 5, the pipe 163 from the pump unit 110 to the servo valve 140 and the pipe 164 from the servo valve 140 to the hydraulic oil tank 120 are connected via a bypass pipe 165. All of the hydraulic oil supplied by the pump unit 110 does not go to the hydraulic cylinder unit 130, and a part is returned to the hydraulic oil tank 120 via the bypass pipe 165. In addition, in order to prevent the backflow of the hydraulic oil in the pipes 163 and 164, check valves 166 and 167 are provided in the respective pipes.

  As described above, in the servo valve type vibration test apparatus, the controller 102 controls the servo valve 140 to periodically switch the hydraulic oil to be sent to the first pressure chamber 131a or the second pressure chamber 131b. Thus, the vibration table 150 is reciprocated. In the servo valve type hydraulic vibration testing apparatus, a part of the hydraulic fluid circulated at a high pressure and a large flow rate is sent to the hydraulic cylinder unit 130 by the servo valve 140. Therefore, the first pressure chamber 131a and the second pressure chamber When the hydraulic oil is sent to which of 131b, the pressure in the pressure chamber to which the hydraulic oil is sent rises instantaneously to a high pressure, and the moving direction of the vibration table 150 is switched without causing a time lag. For this reason, it is possible to vibrate the vibration table at a high frequency.

  The vibration table 150 is provided with an acceleration sensor 103, and the controller 102 calculates the displacement, speed, or acceleration of the vibration table 150 based on the detection result of the acceleration sensor 103, and the desired displacement, speed, or acceleration. The servo valve 140 can be controlled so that the vibration table 150 vibrates with a waveform.

  In the hydraulic actuator using the servo valve as described above, in order to supply hydraulic oil having a desired pressure to the hydraulic cylinder, it is necessary to continuously drive a pump having a sufficiently large flow rate. For this reason, the amount of energy consumed by the vibration test apparatus using such a pump is much larger than the energy required for exciting the subject, and wasteful energy is consumed. In addition, a large-capacity hydraulic oil tank is required to circulate the hydraulic oil by such a pump.

  The present invention has been made to solve the above problem, and does not require a large pump or hydraulic oil tank, and can vibrate the subject at a high frequency while applying a large load to the subject. The purpose is to provide.

In order to achieve the above object, the vibration test apparatus according to the present invention includes a hydraulic pump having a first suction port and a second suction port and a reversible hydraulic pump, a piston, and a piston. A hydraulic cylinder unit including a sleeve divided into pressure chambers and a piston rod connected to the piston and having a tip projecting outside the sleeve; a vibration table provided at the tip of the piston rod; a first pressure chamber; a first pipe connecting the first suction and discharge port, a second and a pipe connecting the second pressure chamber and the first intake port, the first pressure chamber by the hydraulic pump is reversed operates in forward and reverse directions And a bypass test pipe for communicating the first pipe and the second pipe by alternately applying hydraulic pressure to the second pressure chamber to reciprocate the piston to vibrate the subject fixed to the vibration table. And bypass The provided midway further comprises a first pressure chamber and second pressure chamber and the accumulator applying a predetermined pressure, the accumulator is the magnitude of the predetermined pressure applied to the first pressure chamber and the second pressure chamber, the hydraulic cylinder It is set larger than the minimum pressure required for driving the cylinder of the unit.

In the vibration testing apparatus of the present invention, a pump driven in both forward and reverse directions by a servo motor is used, and the hydraulic cylinder unit is driven by directly connecting the pump to the hydraulic cylinder unit without a servo valve. In the vibration testing apparatus of the present invention, since the hydraulic cylinder unit is intended to be driven in accordance with the flow rate and direction of hydraulic fluid output from the pump, a large pump or as a servo-valve of the vibration testing apparatus working Does not require an oil tank. Further, for the above reason, the energy consumption by the vibration test apparatus of the present invention is not so large, so that the energy consumption can be greatly suppressed as compared with the servo valve type vibration test apparatus. .

  In a pump driven in both forward and reverse directions by a servo motor, the pressure of the hydraulic oil decreases when the driving direction of the pump is reversed, and a time lag of several tens of milliseconds occurs until this pressure sufficiently increases. There is a feature. For this reason, if the pump is simply connected to the hydraulic cylinder unit, the time lag occurs when the driving direction of the pump is reversed and the movement direction of the vibration table is switched. I can't move it. For this reason, the subject cannot be vibrated at a high frequency (several tens of Hz or more) such that this time lag cannot be ignored. However, in the present invention, since the accumulator applies back pressure to the first pressure chamber and the second pressure chamber of the hydraulic cylinder unit via the bypass pipe, the pressure of the hydraulic oil can be reduced even if the drive direction of the pump is reversed. There is almost no decrease, and the above time lag is extremely small. For this reason, in the vibration test apparatus of the present invention, the subject can be vibrated at a high frequency.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a circuit diagram of a vibration test apparatus according to this embodiment. As shown in FIG. 1, the vibration testing apparatus 1 of the present embodiment includes a pump unit 10, a hydraulic oil tank 20, a hydraulic cylinder unit 30, a vibration table 50, and an accumulator 70. The subject W moves up and down and vibrates the subject W fixed thereon.

  The pump unit 10 includes a pump body 11 and a servo motor 12. The servo motor 12 is driven by an alternating current output from the servo amplifier 4, and can drive the drive shaft 12a in both forward and reverse directions, and can precisely rotate the drive shaft 12a. It can be adjusted. The servo motor 12 is a low-inertia AC servo motor capable of high-output and high-repetition-rate inversion driving.

  The pump body 11 is a piston pump capable of sending hydraulic oil from the first intake / exhaust port 11a to the second intake / exhaust port 11b or from the second intake / exhaust port 11b to the first intake / exhaust port 11a. Then, by driving the pump body 11 by the servo motor 12, the flow rate and direction of the hydraulic oil supplied by the pump body 11 can be changed. For example, when the servo motor 12 is driven to reciprocate at a constant cycle, the flow rate and direction of hydraulic fluid flowing between the first intake / exhaust port 11a and the second intake / exhaust port 11b change periodically.

  The cylinder unit 30 includes a sleeve 31, a piston 32 that can move within the sleeve 31, and a piston rod 33 that projects from one surface of the piston 32 to the outside of the sleeve 31. A vibration table 50 is fixed to the tip of the piston rod 33. The inside of the sleeve 31 is divided into a first pressure chamber 31 a and a second pressure chamber 31 b by a piston 32. Hydraulic fluid is sealed in the first pressure chamber 31a and the second pressure chamber 31b. The first pressure chamber 31a and the second pressure chamber 31b are connected to the first intake / exhaust port 11a and the second intake / exhaust port 11b of the pump body 11 via pipes 61 and 62, respectively. In addition, as the pipes 61 and 62, a high-pressure hose that can withstand a pressure increase (approximately several tens of MPa) of hydraulic oil generated when the vibration table 50 is moved (not causing elastic deformation) is used.

  The hydraulic oil tank 20 is connected to the first pressure chamber 31a and the second pressure chamber 31b via check valves 63 and 64, respectively. Each check valve 63, 64 opens when the internal pressure of the first pressure chamber 31a and the second pressure chamber 31b becomes smaller than the hydraulic pressure (atmospheric pressure) in the hydraulic oil tank 20, and operates from the hydraulic oil tank 20. Supply oil. In this embodiment, when the hydraulic cylinder unit 30 is attached to the vibration test apparatus 1 and the first pressure chamber 31a and the second pressure chamber 31b are filled with the hydraulic oil, the check valves 63 and 64 are opened and the hydraulic oil tank is opened. The hydraulic oil moves from 20 to the pressure chambers 31a and 31b.

  Specifically, the first pressure chamber 31a and the second pressure chamber 31b are provided with a valve (not shown) for releasing air, the valve of the first pressure chamber 31a is opened, and the second pressure chamber 31b With the valve closed, the pump unit 10 is driven so that hydraulic oil and air are sent from the second intake / exhaust port 11b to the first intake / exhaust port 11a. Then, the air in the second pressure chamber 31b and the pipe 62 is released from the valve of the first pressure chamber 31a through the pipe 61. And since the pressure of the 2nd pressure chamber 31b falls below atmospheric pressure, the non-return valve 64 opens and hydraulic oil is filled into the 1st pressure chamber 31a via piping 62,61.

  After the hydraulic oil is filled in the first pressure chamber 31a, the valve of the first pressure chamber 31a is closed, the valve of the second pressure chamber 31b is opened, and the hydraulic oil is sent from the first intake / exhaust port 11a to the second intake / exhaust port 11b. The pump unit 10 is driven so that Then, the air in the second pressure chamber 31b and the pipe 62 escapes from the valve of the second pressure chamber 31b, and the piston 32 rises and the hydraulic oil filled in the first pressure chamber 31a is pushed out to the pipe 61. It is. When the piston 32 rises to the top dead center, the pressure of the hydraulic oil in the first pressure chamber 31a and the pipe 61 becomes less than atmospheric pressure, the check valve 63 is opened, and the hydraulic oil moves to the second pressure chamber 31b. After the second pressure chamber 31b is filled with hydraulic oil, the valve of the second pressure chamber 31b is closed.

  In the vibration test apparatus 1 described above, a mechanism for vibrating the vibration table 50 will be described below. When raising the vibration table 50, the pump unit 10 is driven so that the hydraulic oil moves from the first intake / exhaust port 11a to the second intake / exhaust port 11b. Then, the hydraulic oil is supplied to the second pressure chamber 31b through the pipe 62, the piston 32 is pushed into the first pressure chamber 31a, and the piston rod 33 and the vibration table 50 are raised. The hydraulic oil in the first pressure chamber 31a moves to the pump unit 10 via the pipe 61 as the piston 32 moves, and is sent from the pump unit 10 to the second pressure chamber 31b via the pipe 62.

  When lowering the vibration table 50, the pump unit 10 is driven so that the hydraulic oil moves from the second intake / exhaust port 11b to the first intake / exhaust port 11a. Then, the hydraulic oil is supplied to the first pressure chamber 31a via the pipe 61, the piston 32 is pushed into the second pressure chamber 31b, and the piston rod 33 and the vibration table 50 are lowered. The hydraulic oil in the second pressure chamber 31b moves to the pump unit 10 via the pipe 62 as the piston 32 moves, and is sent from the pump unit 10 to the first pressure chamber 31a via the pipe 61.

  As shown in FIG. 1, the acceleration sensor 3 is attached to the vibration table 50 of the vibration test apparatus 1 of the present embodiment. The controller 2 calculates the displacement, speed, or acceleration of the vibration table 50 based on the detection result of the acceleration sensor 3, and sets a target value to be given to the servo amplifier 4 based on the calculation result. Send to. The servo amplifier 4 generates an alternating current having a period and amplitude set based on a target value designated by the controller 2 from the power supplied from the power supply 5 and outputs the alternating current to the servo motor 12. Accordingly, the vibration table 50 can be vibrated with a predetermined displacement, speed, or acceleration amplitude, for example. Instead of the acceleration sensor 3, a displacement sensor or a speed sensor may be used.

  Thus, in this embodiment, the vibration table 50 is supplied by supplying hydraulic oil to the first pressure chamber 31a or the second pressure chamber 31b of the hydraulic cylinder unit 30 by the pump unit 10 that can be driven in both forward and reverse directions. Is moved up and down to vibrate the subject W fixed thereon.

  Furthermore, the vibration test apparatus 1 of the present embodiment includes a bypass pipe 65 that bypasses the pipes 61 and 62, and an accumulator 70 provided in the middle of the bypass pipe 65. The accumulator 70 is a pressure vessel in which a gas layer such as nitrogen gas having a predetermined pressure is formed, and the first pressure chamber 31a or the second pressure chamber 31b of the hydraulic cylinder unit 30 is connected via pipes 61 and 62. Pressurize.

  In a configuration that does not include the bypass pipe 65 and the accumulator 70, the pipe on the side not supplied with hydraulic oil (the pipe 61 when the vibration table 50 is raised and the pipe 62 when the vibration table 50 is lowered) is as low as close to atmospheric pressure. It is pressure. Therefore, immediately after the raising and lowering of the vibration table 50 are switched, the pressure of the piping and pressure chamber to which hydraulic fluid is supplied is high enough to move the piston 32 from this low pressure (10 to several tens of MPa). It takes a time of several tens of milliseconds until the time is reached. This period is a time lag in which the vibration table 50 does not move. For this reason, since this time lag is not negligible with respect to the vibration period, the vibration table 50 cannot be vibrated at a high frequency of several tens of Hz or more.

  In the vibration test apparatus 1 of the present embodiment, the accumulator 70 is pressurized so that the pressure in the piping and pressure chamber to which hydraulic oil is supplied can maintain the high pressure. Even immediately after the rise and fall are switched, the pressure in the piping and pressure chamber on the side where the hydraulic oil is supplied is kept sufficiently high. For this reason, the time lag in the structure without the accumulator 70 hardly occurs, and the vibration table 50 can be vibrated at a frequency of several tens Hz or more. In order to make the time lag as small as possible, the pressure of the gas layer of the accumulator 70, that is, the pressure applied to the hydraulic oil by the accumulator 70 is set to be larger than the minimum pressure required for the movement of the piston 32. . In addition, as the bypass pipe 65, a high-pressure hose or the like that can sufficiently withstand the pressure applied to the hydraulic oil by the accumulator 70 is used.

  Further, since the pump body 11 of the pump unit 10 is a piston pump, pulsation occurs during driving. In the present embodiment, an accumulator 70 is provided between the pump unit 10 and the hydraulic cylinder unit 30. The pulsation is absorbed by the accumulator 70. This feature is that, as shown in FIG. 2A, the subject W is sandwiched between the frame 52 and the pressurizing table 50 to raise the vibration table 50, and the subject is subjected to a compressive static load in the vertical direction. This is useful when a compression test is applied. Similarly, as shown in FIG. 2 (b), the above-described feature is that the jigs 53 and 54 attached to the vibration table 50 and the frame 52 ′ are fixed to the subject, the vibration table 50 is lowered, This is also useful when performing a tensile test in which a vertical tensile static load is applied to the specimen W.

  Further, as shown in FIGS. 2A and 2B, the subject W is arranged between the frame and the vibration table, and the vibration table is reciprocated to periodically apply the load applied to the subject W. It is also possible to perform a repeated load test that fluctuates. In that case, a load sensor such as a load cell may be provided on the frame or the vibration table, and the controller 2 may control the pump unit based on the measurement result of the load sensor. For example, it is possible to perform a so-called fatigue test in which a load is repeatedly applied to the subject W so that the amplitude of the load applied to the subject W is constant.

  Next, the result of the vibration test performed by the vibration test apparatus 1 of the present embodiment described above and the result of the vibration test performed by the vibration test apparatus not provided with an accumulator will be described. FIG. 3 is a graph plotting acceleration and displacement when the servo motor 12 is driven in reverse so that the axis rotation angle has a sine waveform with a frequency of 50 Hz in the vibration test apparatus 1 (example) of the present embodiment. . FIG. 4 is a graph plotting acceleration and displacement when the servo motor 12 is driven in reverse so that the axis rotation angle has a sine waveform with a frequency of 50 Hz in a vibration test apparatus (comparative example) without an accumulator. is there. There is no difference between the vibration test apparatus of the example and the vibration test apparatus of the comparative example except for the presence or absence of an accumulator, and the amplitude and frequency of the alternating current sent from the servo amplifier 4 to the servo motor 12 are the same as in the example. There is no difference between the comparative examples.

  As shown in FIG. 3, in the embodiment, the acceleration and displacement waveforms are sinusoidal, and it can be seen that the workpiece W vibrates at 50 Hz. On the other hand, as shown in FIG. 4, in the comparative example, the acceleration waveform is greatly collapsed from the sine wave, and the amplitude thereof is less than 1/10 of the embodiment. And in the comparative example, the displacement of the workpiece | work W has hardly changed.

  Thus, the vibration test apparatus of this embodiment can vibrate the subject at a high frequency.

1 is a circuit diagram of a vibration test apparatus according to an embodiment of the present invention. 1 is a diagram showing a configuration for applying a static load to a subject in a vibration test apparatus according to an embodiment of the present invention. FIG. It is the graph which plotted the acceleration and displacement of the vibration table in the Example of this invention. It is the graph which plotted the acceleration and displacement of the vibration table in a comparative example. It is an example of the circuit diagram of the conventional hydraulic vibration test apparatus which uses a servo valve.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vibration test apparatus 2 Controller 3 Acceleration sensor 4 Servo amplifier 5 Power supply 10 Pump unit 11 Pump main body 11a 1st intake / exhaust port 11b 2nd intake / exhaust port 12 Servo motor 20 Hydraulic oil tank 30 Hydraulic cylinder unit 31 Sleeve 31a 1st pressure chamber 31b 1st 2 Pressure chamber 32 Piston 33 Piston rod 50 Excitation table 65 Bypass pipe 70 Accumulator

Claims (7)

A hydraulic pump capable of reversing operation having a first suction port and a second suction port;
A hydraulic cylinder unit comprising: a piston; a sleeve whose internal space is divided into a first pressure chamber and a second pressure chamber by the piston; and a piston rod connected to the piston and having a tip protruding outside the sleeve; ,
A vibration table provided at a tip of the piston rod;
A first pipe connecting the first pressure chamber and the first intake / exhaust port;
A second pipe connecting the second pressure chamber and the second intake / exhaust port;
The a, the hydraulic pump is the piston to reciprocate over a hydraulic alternately in the first pressure chamber and the second pressure chamber by reversing operation in forward and reverse directions, it is fixed to the vibrating table A vibration test apparatus for vibrating a subject ,
A bypass pipe for communicating the first pipe and the second pipe,
Wherein provided on the midway of the bypass pipe, further comprising a, an accumulator applying a predetermined pressure to the first pressure chamber and said second pressure chamber,
Wherein the predetermined magnitude of pressure, vibration test apparatus characterized by being larger than the minimum pressure required to drive the hydraulic cylinder unit. The vibration test apparatus according to claim 1, wherein the hydraulic pump is a piston pump. The vibration test apparatus according to claim 1, further comprising a servo motor that drives the hydraulic pump. A sensor and a controller for controlling the servo motor;
The vibration test apparatus according to claim 3, wherein the controller controls the servo motor based on a detection result of the sensor. The sensor includes a second sensor for measuring displacement, velocity or acceleration of the piston rod;
The vibration test apparatus according to claim 4, wherein the controller controls the servo motor so that the piston rod is driven with a predetermined displacement, speed, or acceleration based on a detection result of the sensor. 6. The controller according to claim 4, wherein the controller controls the servo motor so that the vibration table vibrates with a waveform of a predetermined displacement, speed, or acceleration based on a detection result of the sensor. Vibration test equipment. The sensor includes a load sensor that measures a load applied to the subject,
The vibration test apparatus according to claim 4, wherein the controller controls the hydraulic cylinder unit based on a detection result of the sensor such that a load applied to the subject changes according to a predetermined waveform.

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