JPS639615B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a start-up control device for a testing machine such as a vibration testing machine or a fatigue testing machine.

For example, in a testing machine such as a vibration testing machine, an actuator that vibrates a vibration table is controlled by control pressure oil from a two-stage amplification type servo valve consisting of a pilot valve and a main valve. The pressure oil of hydraulic pressure P _S1 to the pilot valve constituting this servo valve and the pressure oil of hydraulic pressure P _S2 to the main valve are supplied by branching from the same hydraulic pressure supply.

In a hydraulic pressure supply system configured as described above, the spool of the main valve may not always be at the center position when the input signal for driving the pilot valve is set to zero and the system is started. In this way, if activation is started with the spool of the main valve being at a position offset from the center, the vibration table will unexpectedly move before it moves in response to the input signal. In order to prevent this movement, a compensating means is provided to return the spool displacement of the main valve to the input side, but it is impossible to completely eliminate even a slight movement of the vibration table upon startup. This unexpected movement of the shaking table may damage the test object on the shaking table before it is properly tested.

The present invention has been made based on the above-mentioned matters, and an object of the present invention is to provide a start-up control device for a test machine that can prevent unexpected movement of a test object that occurs during start-up.

The present invention is characterized in that pressure oil from a hydraulic supply system is applied to an actuator by a two-stage amplification type servo valve consisting of a pilot valve and a main valve, and the test object is vibrated by this actuator. In the test machine, the hydraulic pressure supply system consists of a pilot hydraulic pressure supply system to the pilot valve and a main hydraulic pressure supply system to the main valve, and these hydraulic pressure supply systems are connected via a pressure equalization check valve, and the main hydraulic pressure is A delay means for delaying starting of the motor for driving the hydraulic power source of the supply system after activation of the motor for driving the hydraulic pressure of the pilot hydraulic supply system, and a signal from a detector for detecting the position of the spool of the main valve. A zero position control means is provided which controls the position of the pilot valve spool and returns the main valve spool to the center position by this control before driving the motor of the hydraulic drive source.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows the configuration of a vibration tester equipped with an embodiment of the activation control device of the present invention, and in the figure, 1 is a vibration table. This vibration table 1 is vibrated by a horizontal vibrator 2 and a vertical vibrator 3. Each of these vibrators 2 and 3 is provided with a servo valve 4. Further, pressure oil is supplied to these vibrators 2 and 3 from a main hydraulic pressure source system 5 and a pilot hydraulic pressure source system 6 through a servo valve 4. The main hydraulic power source system 5 and the pilot hydraulic power source system 6 are constructed almost in the same way, and include electromagnetic valves 7a, 7b, check valves 8a, 8b, pressure regulating valves 9a, 9b, hydraulic pumps 10a, 10b, and a filter 11a. , 11b, motors 12a, 12b and tanks 13a, 13b
It is equipped with such things as A discharge side pipe line is connected to the hydraulic power source systems 5 and 6 via a pressure equalization check valve 14. Further, pressure gauges 15a and 15b are provided in the discharge side pipes of the hydraulic power source systems 5 and 6, and an accumulator 16 is provided in the discharge side pipe of the main hydraulic power source system 5. A delay means 17 is connected to the motor 12a on the main oil pressure source 5 side to apply a starting input signal to the motor 12a t seconds after the motor 12b on the pilot oil pressure source 6 side is started.

The detailed configuration of the above-mentioned vibrators 2, 3 and servo valve 4 will be explained with reference to FIG. In FIG. 2, parts with the same symbols as in FIG. 1 are the same parts. 1
8 is the pressure oil at pressure P _S1 from the main hydraulic power source system 5 at pressure P ₁
a main valve that controls the supply of pressure oil to the vibration exciters 2 and 3;
A pilot valve 19 supplies the pressure P _S2 from the pilot oil pressure source system 6 to the pilot portion of the main valve 18 as pressure oil P1 _' . Pilot valve 19
The force motor 2 is attached to one end of the spool 19a.
0 is connected, and a zero adjuster 21 is provided at the other end. The force motor 20 receives an input signal E ₁
an adder 23, a servo amplifier 24, which calculates the deviation _e1 between the transformer signals of the vibrators 2 and 3 from the detector 22;
Deviation signal _e1 from servo amplifier 24 and detector 25
An adder 26 and a servo amplifier 27 are connected in sequence for determining the deviation e ₂ from the transformed voltage signal of the main valve 18a. These structures constitute an electro-hydraulic servo control mechanism.

Next, a case will be described in which a vibration testing machine is started using the above-described apparatus of the present invention.

First, in order to drive the test machine, the motor 12b on the pilot hydraulic power source system 6 is started, and t seconds later, the motor 12a on the main hydraulic power source 5 is started.
At this time, the pressure regulating valve 9b is set to a low pressure of, for example, 30 kg/ ^cm2 , and the pressure regulating valve 9a is set to, for example, a low pressure of about 30 kg/cm2.
Assuming that the pressure is set at a high pressure of ^about 210Kg/cm2, the hydraulic pressure P _S1 to the main valve 18 and the pilot valve 19
The hydraulic pressure P _S2 changes over time as shown in FIG. That is, first, pressure oil with a pressure P _S2 is supplied to the pilot valve 19, and after t seconds, pressure oil with a pressure P _S1 is supplied to the main valve 18. The pressure of P _S1
The pressure oil flows into the discharge side pipe of the pilot hydraulic power source system 6 through the pressure equalization check valve 14, and soon the pressures P _S1 and P _S2 of the discharge side pipes of both the hydraulic power source systems 5 and 6 become the same pressure. For this reason, the capacity of the hydraulic pump 10b of the pilot hydraulic power source system 6 is, for example, 10/
It can be as small as min.

The function and effect of the pressure equalization check valve 14 will be further explained with reference to FIGS. 1 and 2.

When the pilot hydraulic power source system 6 is activated, its output pressure P _S2 does not flow to the right side (main circuit) of the check valve 14, but acts only on the pilot 19 of the servo valve 4. Therefore, the main valve 18 is controlled by the pilot valve 19.
The spool 18a is controlled to the zero position. When the main hydraulic power source system 5 is activated after t seconds, its output pressure P _S1 acts on the main valve 18 of the servo valve 4. Then, the output pressure P _S1 increases by the pressure regulating valve 9 (usually 210
up to Kg/ ^cm2 ). When an excitation experiment is started and the flow rate of the pilot hydraulic power source 6 is insufficient, the check valve 14 is passed from the main circuit side to compensate for the insufficient flow rate of the pilot system.

The pilot hydraulic power source 6 has a small flow capacity and is used only at startup. In addition, the pilot hydraulic power source system 6 is supplied with pressure oil from the main hydraulic power source system 5 when the main hydraulic power source system 5 starts, so the pilot hydraulic power source system 6
role ends and ceases. By providing the check valve 14, the pilot hydraulic power source system 6 needs to have a very small capacity, so the device becomes inexpensive.

The reason why the vibration table 1 does not move and remains stationary at startup due to such operation control will be explained in more detail. Now when the input signal E ₁ is zero,
The pilot oil pressure source system 6 is activated and pressure oil at pressure P _S2 is supplied to the pilot valve 19. This pilot valve 19 is connected to a spool 19 as shown in FIG.
The spool 19a has springs 21a at both ends of the spool 19a, and the zero adjustment of the spool 19a is performed by a zero adjustment screw 21 that changes the bus force. Therefore, if the control current does not flow to the force motor 20, the spool 1
Since 9a is at the zero position in the center, the pressure oil P _S2 does not flow to both ends A of the main valve spool 18a. On the other hand, when the spool 18a of the main valve 18 is not at the center position, the detector 25 detects the position of the spool 18a of the main valve 18, and the detected position is fed back to the adder 26. Therefore, the force motor 20 moves the spool of the pilot valve 19 in response to the deviation signal _e2 from the adder 26. This allows one output hydraulic pressure (on the drawing,
If the output oil pressure on the left side) R ₁ ′ becomes larger than the output oil pressure on the other side P ₁ ′ (the output oil pressure on the right side in the drawing), then
The spool 18a of the main valve 18 moves to the right in the drawing to control the servo system of the pilot valve 19, the main valve 18, the servo amplifier 27, and the adder 26 to the zero position. That is, the spool of the main valve 18 is positioned at the center. This operation takes much less time than the t seconds shown in FIG. Thereafter, the main hydraulic power source system is driven by the delay means 17, but the main valve 18 has already been activated.
Since the spool 18a has returned to the neutral position, the vibration table 1 is stopped without causing any unexpected movement.

As described in detail above, according to the present invention, it is possible to suppress the phenomenon of vibration movement when starting up the hydraulic power source system, and therefore, the reliability of the testing machine can be improved.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of a vibration testing machine equipped with an embodiment of the device of the present invention, and FIG. 2 is a diagram showing the configuration of an electro-hydraulic servo mechanism used in the device of the present invention.
FIG. 3 is a diagram showing the characteristics of the oil pressure P _S1 to the main valve and the oil pressure P _S2 to the pilot valve controlled by the device of the present invention. 1... Vibration table, 2, 3... Vibrator, 4... Servo valve, 5... Main hydraulic power source system, 6... Pilot hydraulic power source system, 14... Check valve for pressure equalization, 17... Delay means , 18...Main valve, 19...Pilot valve, 2
0...Force motor.

Claims (1)

[Claims] 1. In a test machine in which pressure oil from a hydraulic supply device is applied to an actuator by a two-stage amplification type servo valve consisting of a pilot valve and a main valve, and the test object is vibrated by this actuator, the hydraulic pressure supply device The system consists of a pilot hydraulic pressure supply system to the pilot valve and a main hydraulic pressure supply system to the main valve, and these hydraulic pressure supply systems are connected via a pressure equalization check valve, and a The motor is equipped with a delay means for delaying starting of the motor after the motor for driving the hydraulic power source of the pilot hydraulic pressure supply system is started, and a signal from a detector that detects the position of the main valve spool to detect the position of the pilot valve spool. 1. A starting control device for a testing machine, characterized in that the starting control device for a test machine is provided with zero position control means for returning a spool of a main valve to a central position before driving a motor of the hydraulic drive source.