JPS6315804Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an apparatus for testing the properties of various materials, and in particular to an improvement of an electro-hydraulic material testing apparatus that applies hydraulic pressure to a test piece and electrically detects measured values.

2. Description of the Related Art Conventionally, an electrohydraulic material testing device shown in FIG. 1 has been known. That is, an oscillator 5, a position setting volume 14, and displacement, elongation, and load detectors 8, 9, and 1 corresponding to each test mode.
The signal from 0 is input via the adder 4 to the servo valve 2 of the hydraulic pressure control system of the actuator 7 that applies hydraulic pressure (oil pressure, etc.) to the test piece P, and the test mode changeover switch 1 is used to select the desired mode. The mode is configured such that the mode is selectively switched and the measured value of the mode is electrically detected. In the figure, 6 and 3 are an amplifier and an ammeter installed in the signal line between the adder 4 and the servo valve 2, and 11, 12,
Reference numeral 13 denotes a feedback amplifier installed in the signal line between each of the detectors 8 to 10 and the test mode changeover switch 1, respectively.

In general, material testing equipment that uses this type of hydraulic pressure is
While the hydraulic pressure of the hydraulic pressure source is not acting on the actuator 7, that is, while it is not in use, the center position of the spool of the servo valve 2 and the position of the actuator 7 change, and if they remain in this state. When the hydraulic pressure source (pump) is driven and hydraulic pressure is applied, a large displacement is instantaneously applied to the actuator 7 depending on the position of the spool and the actuator 7, and at the same time, the actuator 7
If the various sensors, test piece P, and other parts attached to the test piece P are destroyed, or even if they are not destroyed, the test cannot continue, and the test piece P must be replaced and the test restarted, or the test piece P must be reattached. , the reference level from the sensor must be readjusted, and other problems arise.

For this reason, the conventional device requires complicated operations as described below. That is, before starting to use the device, after cutting off the hydraulic pressure supplied to the servo valve 2 from the hydraulic pressure source and switching to the displacement mode state, the position setting volume 14 is operated to set the servo valve ammeter 3. This operation involves monitoring the value, adjusting it so that it becomes zero, and then applying hydraulic pressure to the servo valve 2.

This idea was made in view of the above circumstances,
When the power switch of the device is turned on, the displacement mode selector switch is turned on in conjunction with this, and it also prevents signals other than the oscillator from inputting to the actuator control system, and also prevents signals other than the oscillator from inputting to the actuator control system. By configuring the hydraulic pressure source drive switch to turn on when there is no input, it is possible to start and end the use of the device without having to perform complicated operations like in the past.
The object of the present invention is to provide an electro-hydraulic material testing device that is easy to handle without causing any damage to test pieces or other parts.

The basic configuration of this device is to input signals from the oscillator, position setter, and detector corresponding to each test mode to the actuator control system that applies hydraulic pressure to the test piece via an adder. In an electro-hydraulic material testing device that is configured to selectively switch to a desired test mode state and electrically detect the measured value in that mode, when the power switch of the device is turned on, a related operation occurs. a circuit that inputs the detection signal of the displacement detector into the adder as a negative feedback signal when the displacement mode is set; and a circuit that inputs the detection signal of the displacement detector when the displacement mode is set to the negative feedback signal. and a circuit for inputting to the adder in order to cancel the oscillator, thereby preventing signals other than the oscillator from inputting to the control system of the actuator when the displacement mode is entered, and further preventing signals other than the oscillator from inputting to the control system of the actuator. An electro-hydraulic material testing device is provided, characterized in that it is provided with a hydraulic pressure source drive circuit that operates when there is no input to the control system.

Hereinafter, one embodiment of this invention will be described with reference to FIG. 2 (in this invention, the same components as those of the prior art are given the same reference numerals in the drawings).

Feedback amplifiers 11, 12, 13 are connected to the feedback signal lines of the displacement, elongation, and load detectors 8, 9, and 10, respectively.
Feedback analog switches 15a, 15b, and 15c are interposed between the adder 4' and the adder 4'. These analog switches 15a to 15c are turned on and off by the output signal from the data receiver 18, and this data receiver 18 is connected to the computer.
The CPU (central processing
unit) 25, and this CPU2
It operates with the command signal from 5.

Detectors 8 to 10 are located between the feedback amplifiers 11 to 13 and analog switches 15a to 15c.
Analog switches 16a, 16b, and 16c are interposed in signal lines branched from each feedback signal line. These analog switches 16a to 16
c is the output signal from another data receiver 19
This data receiver 19 is a device that turns ON and OFF.
is connected to the CPU 2 via the computer bus 26.
The CPU 25 is electrically connected to the CPU 25, and is operated by command signals from the CPU 25. The analog switches 16a to 16c of the branch signal line are electrically connected to an A/D converter 20. A/D converter 20 is electrically connected to memory 24 via computer bus 26. This memory 24
is electrically connected to CPU 25 via computer bus 26. Position setting D/A converter 1 whose output signal is input to adder 4'
4' is connected to the CPU 25 via the computer bus 26.
is electrically connected to. 23 is a keyboard encoder and test mode changeover switch 17a, 17
b, 17c, a start switch 21, and a stop switch 22 are provided. The test mode changeover switch 17a is for the displacement mode, the test mode changeover switch 17b is for the extension mode, and the test mode changeover switch 17c is for the load mode.The start switch 21 and the stop switch 22 are for the oscillator 5.
This is used to start and stop the system. Then, the switching signals from each of the above switches are encoded into a predetermined information signal by the keyboard encoder 23, and the information signal is transmitted via the computer bus 26.
It is designed to be input to CPU25. Also,
When you turn on the power switch of the device, memory 2
4, as an initial set, sends the same information signal to the CPU as when the test mode changeover switch 17a is turned on.
It is scheduled to be sent out on the 25th.

Next, the operation of the electro-hydraulic material testing apparatus of this invention having the above structure will be explained with reference to the timing chart shown in FIG. When starting to use the device, turn on the power switch of the device (time t1) and turn on the displacement mode changeover switch 17a.
The same information signal as when the computer bus 26 is outputted from the memory 24,
It is recognized by the CPU 25 via. At this time, the program contents previously input into the memory 24 are
The command signal is read out by the CPU 25, and a corresponding command signal is sent from the CPU 25 to the data receiver 19, and this data receiver 19 switches only the output signal b1 to "1". Of these, only 16a is turned on. Therefore, only the detection signal VE1 of the displacement detector 8 is converted into a digital signal by the A/D converter 20 and stored in the memory 24 via the computer bus 26. This means that the amount of displacement (signal amount corresponding to the amount of displacement) currently applied to the test piece P is stored in the memory 24. Then, the displacement amount (corresponding to signal VE1) stored in this memory 24 is calculated by the CPU 25, and inputted to the position setting D/A converter 14' via the computer bus 26. At the same time (time t2) that the signal Vdc (=VE1) outputted after D/A conversion by the A converter 14' is input to the adder 4' (time t2), the data receiver 18 outputs the output signal a1 based on the command signal from the CPU 25.
VE1 from the feedback amplifier 11 is negatively fed back to the adder 4' via the analog switch 15a.

As a result, the signal Vdc (=VE1) of the position setting D/A converter 14' is input to the adder 4'.
The detection signal VE1 of the displacement detector 8, which is negatively fed back, is canceled out and the output of the adder 4' is held at zero.
When the output of adder 4' is held at zero in this way,
After that, for example, at time t3 in FIG.
A drive command signal is sent from the CPU 25 to the hydraulic source drive circuit 28 via the computer bus 26.
Due to the operation of this hydraulic pressure source drive circuit 28, the hydraulic pressure source 29
Hydraulic pressure from the actuator 7 acts on the actuator 7. From this point on, the test machine enters the displacement mode.

To switch from this state to the load mode state, the load mode switching switch 17c is turned ON. When the switch 17c is turned ON, the analog switch 16
c, 15c are turned ON, and the position setting D/
The signal input from the A converter 14' to the adder 4 becomes the detection signal VE3 of the load detector 10, and the detection signal VE3 of the load detector 10 is also input to the adder 4.
This is negatively fed back to the adder 4, and the output of the adder 4 is held at zero as a result.

In addition, when switching to the extension mode state, by switching the switch 17b to ON, the analog switches 15b and 16b are turned ON, and the extension detection signal VE2 is inputted to the adder 4 in the same manner as above, and is canceled out by the adder 4. ′ is held at zero.

As mentioned above, the electro-hydraulic material testing device of this invention has a circuit that operates in conjunction with the power switch of the device to set it to the displacement mode when it is turned on, and a circuit that changes the detection signal of the displacement detector to negative when the device enters the displacement mode. A circuit for inputting a feedback signal to an adder and a circuit for inputting a detection signal of a displacement detector to the adder in order to cancel the negative feedback signal when the displacement mode is set are provided. This is because a circuit is provided to prevent signals other than the oscillator from being input to the actuator control system when the oscillator is activated, and to drive the hydraulic pressure source that operates when no signals other than the oscillator are input to the actuator control system. It is easy to handle without any complicated operation of the device and without damaging the test piece or other parts.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a conventional testing device, FIG. 2 is a block diagram showing an embodiment of the testing device of this invention, and FIG. 3 is a timing chart showing the operating state of the device shown in FIG. 2... Servo valve, P... Test piece, 4'... Adder, 5... Oscillator, 6... Amplifier, 7... Actuator, 8... Displacement detector, 9... Elongation detector,
10... Load detector, 11-13... Feedback amplifier, 14'... D/A converter for position setting, 15a-15c, 16a-16c... Analog switch, 17a-17c... Test mode changeover switch, 18 , 19...data receiver, 20
...A/D converter, 21...Start switch, 22...Stop switch, 23...Keyboard encoder, 24...Memory, 25...
CPU, 26... Computer bus, 28...
Hydraulic pressure source drive circuit, 29...liquid pressure source.

Claims (1)

[Scope of utility model registration request] Signals from the oscillator, position setter, and detector corresponding to each test mode are input to the control system of the actuator that applies a load to the test piece via an adder, and the signals are selectively set to the desired test mode state. In an electro-hydraulic material testing device that switches to the mode and electrically detects the measured value of the mode, there is a circuit that operates in conjunction with this when the power switch of the device is turned on to switch to displacement mode, and a circuit that switches to displacement mode. a circuit that inputs the detection signal of the displacement detector when the displacement mode is reached as a negative feedback signal to the adder; and a circuit that inputs the detection signal of the displacement detector when the displacement mode is set to the adder in order to cancel it out with the negative feedback signal. By comprising a circuit, when the displacement mode is entered, signals other than the oscillator are prevented from being input to the control system of the actuator, and furthermore, signals other than the oscillator are not input to the control system of the actuator. An electro-hydraulic material testing device characterized by being provided with a hydraulic pressure source drive circuit that operates when the