JPS6315805Y2 - - 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 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 set the desired mode. This mode is configured to be selectively switched and to electrically detect the measured value of the mode. In addition, 6 and 3 in the figure are an amplifier and an ammeter interposed in the signal line between the adder 4 and the servo valve 2, and 11, 12, 13
are each detector 8 to 10 and test mode switch 1
A feedback amplifier is installed in each signal line between the two.

In such conventional devices, when switching from any mode to another mode during a test with the test piece P attached to the actuator 7 of the testing machine, the following complicated operations are required. do. That is, when switching to another mode after selecting an arbitrary mode with the mode changeover switch 1, the output of the oscillator 5 is made zero, and then the hydraulic pressure supplied from the hydraulic pressure source to the servo valve 2 is cut off. The operation involves switching the mode, operating the position setting volume 14, monitoring the servo valve ammeter 3, adjusting the value to zero, and then applying hydraulic pressure to the servo valve 2. This is because, if the mode is switched without turning off the hydraulic pressure to the servo valve 2, the levels of the amplified output signals VE1 to VE3 of the feedback amplifiers 11 to 13 of each mode are different, so the signal after mode switching is If it is larger than the previous signal, the signal is input to the amplifier 6, which activates the servo valve 2, which in turn causes the actuator 7 to move and send signals to the various sensors and test piece P attached to the actuator 7. Force is applied in a shot state. For this reason, even if the sensor, test piece P, and other parts are destroyed, or even if they are not destroyed, they cannot be used as a test piece for continued testing, and the test piece must be replaced and retested, or the test piece must be replaced. This is because a problem arises in that the reference level from the sensor must be readjusted.

This invention was devised to solve the above-mentioned conventional problems, and by preventing signals other than the oscillator from being input to the control system of the actuator when switching the test mode, it is possible to control the switching operation of the mode selection switch. An object of the present invention is to provide an electro-hydraulic material testing device that can be easily handled by smoothly and reliably switching modes without giving any shock to a test piece.

The basic configuration of this device is that signals from the oscillator, position setter, and detector corresponding to each test mode are input to the control system of the actuator 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 of the mode, the detector operates in connection with the test mode switching operation and is in the switched mode. a circuit for inputting only the detection signal of the detector as a negative feedback signal to the adder; It is equipped with an input circuit, and when switching the test mode,
The electrohydraulic material testing apparatus is characterized in that signals other than those from the oscillator are not input to the control system of the actuator.

Hereinafter, one embodiment of this invention will be described with reference to FIG. 2 (in this invention, the same components as those in 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 2
4 is connected to the CPU 25 via the computer bus 26.
is electrically connected to. The output signal is sent to adder 4'
D/A converter 1 for position setting input to
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. Each of these switches 17a-17c, 21, 22 is electrically connected to the CPU 25 via a computer bus 26. The start switch 21 and stop switch 22 are used to start and stop the oscillator 5.

Next, the operation of the electrohydraulic material testing apparatus of this invention having the above configuration will be explained. Turn on the power supply and hydraulic pressure supply mechanism (pump) and turn on the output of the oscillator 5.
Set Vac to zero and turn displacement mode switch 17.
a. When, for example, the displacement mode changeover switch 17a of the extension mode changeover switch 17b and the load mode changeover switch 17c is turned on, only the output signal a1 from the data receiver 18 becomes 1 and a2 and a3 become 1 by a command from the CPU 25. Since it is zero, 15 of the feedback analog switches 15a to 15c
Only a is turned ON, and 15b and 15c are turned OFF, resulting in a displacement mode state. Therefore, only the detection signal VE1 of the displacement detector 8 is negatively fed back to the adder 4' via the feedback amplifier 11 and the analog switch 15a.

When switching from this state to the load mode state, the output of the adder 4' is zero because a negative feedback loop is formed in the displacement mode state until the load mode changeover switch 17c is turned on.
Next, when switching the load mode changeover switch 17c to ON, looking at the load mode to be switched to, the detection signal of the load detector 10 will be
VE3, if you switch to the load mode state as it is, the output signal Vdc of the position setting D/A converter 14' and the load detector 10
A signal representing the difference between the detection signal VE3 and the detection signal VE3 is output from the adder 4' and acts on the servo valve 2 via the amplifier 6.
This will give an excessive shock to the test piece P. Therefore, in this invention, it is possible to smoothly switch from the displacement mode to the load mode without giving any shock to the test piece P by the following action.

That is, as shown in the timing chart of FIG. 3, the load mode changeover switch 17c is turned on at time t1.
When switched to ON, this is transmitted to the CPU via the keyboard encoder 23 and computer bus 26.
It is recognized at 25. Next, the program contents previously input into the memory 24 are read out by the CPU 25, and a corresponding command signal is sent to the CPU 25.
The data receiver 19 changes the output signal b1, which has been in the "1" state, to "0" and also changes the output signal b3 to "1".
Along with this, the analog switch 16a
turns OFF and analog switch 16c turns OFF.
It becomes ON. Therefore, the detection signal of the load detector 10
Only VE3 is converted into a digital signal by A/D converter 20 and stored in memory 24 via computer bus 26. This means that the amount of load currently applied to the test piece P (the amount of signal corresponding to the amount of load) is stored in the memory 24.
Then, the load amount (corresponding to signal VE3) stored in this memory 24 is calculated by the CPU 25, and is inputted to the position setting D/A converter 14' via the computer bus 26. The signal Vdc (=VE3) which is D/A converted and outputted by the /A converter 14' is sent to the adder 4'.
At the same time (time t2), the data receiver 18 changes the output signal a1, which has been in the "0" state, to "0" and switches the output signal a3 to "1" based on the command signal from the CPU 25. , the analog switch 15 is turned ON.
The signal VE3 from the feedback amplifier 13 is negatively fed back to the adder 4' via c. This causes the position setting D/A converter 1 to be input to the adder 4'.
The signal Vdc (=VE3) of the adder 4' and the detection signal VE3 of the load detector 10, which is negatively fed back, are canceled and the output of the adder 4' is held at zero, thereby smoothly switching from the displacement mode state to the load mode state. It means that it was done. After that (time t3), switch 21 is turned on.
When operated, the oscillator 5 is activated and the test is conducted in the corresponding load mode.

In addition, when switching to the extension mode state, the analog switches 15b and 16b are turned ON by switching the extension mode changeover switch 17b to ON.
The elongation detection signal VE2 is input to the adder 4' in the same manner as described above, and they cancel each other out, so that the output of the adder 4' is held at zero.

As mentioned above, the electro-hydraulic material testing device of this invention has a circuit that performs the work related to the test mode switching operation and inputs only the detection signal of the detector of the switched mode to the adder as a negative feedback signal, and a circuit that inputs only the detection signal of the detector in the switched mode activated in connection with the operation to the adder in order to cancel the negative feedback signal, and when switching the test mode, the signal other than the oscillator is input to the actuator. Since the test mode is not input to the control system, the test mode can be changed smoothly and reliably by one-touch operation of the test mode changeover switch without giving any shock to the test piece.

[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 the present invention, and FIG. 3 is a flowchart 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, 14...Position setting device, 15a-15
c, 16a-16c...Analog switch, 17
a~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.

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 in which the mode measurement value is electrically detected by switching to the test mode, only the detection signal of the detector of the switched mode is activated in connection with the test mode switching operation and is used as the negative feedback signal. The circuit includes a circuit that inputs an input to the adder, and a circuit that operates in connection with the test mode switching operation and inputs the detection signal of the detector in the switched mode to the adder in order to cancel out the negative feedback signal, and the test mode An electro-hydraulic material testing device characterized in that during switching, signals other than the oscillator are not input to the control system of the actuator.