JPH09145577A - High speed impact tester - Google Patents

Abstract

(57) 【Abstract】 PROBLEM TO BE SOLVED: To provide a high-speed impact tester in which the speed is prevented from decreasing as much as possible even after an actuator applies an impact force to a specimen. An actuator is driven at a speed according to a speed command, and an impact force is applied to a test piece 13 at a constant speed.
When the load applied to the test piece 13 exceeds a predetermined value, the speed compensation signal is added to the servo valve signal. As a result, the opening area of the servo valve 14 is increased and the hydraulic cylinder 1
2 Inflow increases to compensate for velocity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-speed impact tester that applies a high-speed impact force to a test piece to perform a test.

[0002]

2. Description of the Related Art A high-speed impact tester which gives a high-speed impact force to a resin material such as plastic or a metal material to evaluate the material has been known. With this type of impact tester, it is possible to carry out a low-velocity impact test in which an impact force is applied at a speed of about 2 m / S and a high-velocity impact test in which an impact force is applied at a speed higher than that. In the low-speed impact test, a ramp signal waveform is given to the servo valve as a speed command signal to increase the opening of the servo valve according to the ramp signal waveform to drive the hydraulic actuator, while the displacement of the hydraulic actuator is fed back. The actuator is driven at a speed according to the speed command value. On the other hand, in a high-speed impact test faster than 2 m / S, the servo valve is suddenly set to a predetermined opening according to the speed command, and the hydraulic actuator is driven at high speed without feedback control.

[0003]

In such a conventional high-speed impact tester, an approach section for accelerating the actuator to a constant velocity range is provided in both the low-speed impact test and the high-speed impact test, and the actuator has a constant velocity range. The impact force is applied to the test piece when the temperature reaches the limit. However, in the low-speed impact test, the stroke of the hydraulic actuator is detected and stroke feedback is performed, and the actuator is driven at the speed according to the speed command, but the load collides with the specimen and the load exceeds a predetermined value. When it reaches, the speed decreases. There is a similar problem in the high speed impact test, and even if an impact force is applied to the test piece after the actuator is in the constant speed state, the speed will decrease when the load exceeds a predetermined value.

An object of the present invention is to provide a high-speed impact tester in which the speed does not decrease as much as possible even after the actuator exerts an impact force on the specimen.

[0005]

The present invention is applied to a high-speed impact tester for applying a high-speed impact force to a test piece, and an actuator driven at a speed according to a speed command and a load acting on the test piece. And a speed compensating means for increasing the speed of the actuator when the detected load is equal to or more than a predetermined value.

The actuator applies an impact force to the test piece at a speed according to the speed command. When the load acting on the test piece exceeds a predetermined value, the speed compensation of the actuator is performed by the speed compensator, and the decrease in speed is prevented.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a high speed impact tester according to the present invention will be described with reference to FIG. As shown in FIG.
The high-speed impact tester includes a tester body 10 and a control unit 30. The tester main body 10 applies an impact force to the test piece 13 by a reciprocating hydraulic cylinder 12 provided on the table 11, and the hydraulic cylinder 12 is driven by pressure oil adjusted by a servo valve 14. At the tip of the piston rod of the hydraulic cylinder 12, there is provided a running mechanism that gives an impact force to the test piece after moving in the running section. In both the low-speed impact test and the high-speed impact test, the hydraulic cylinder 12 moves in the accelerating section in the approach section until reaching the uniform speed, and after reaching the uniform speed, the test section is completed only after the approach section is completed. The run-up mechanism is configured so that impact force is applied to.

The impact force applied to the specimen is the load cell 1
5, the stroke of the hydraulic cylinder 12 is detected by the displacement gauge 16. The servo valve 14 is driven and controlled by a servo valve signal from the control unit 30, and the load detected by the load cell 15 and the stroke of the hydraulic cylinder 12 detected by the displacement gauge 16 are input to the control unit 30 as feedback signals.

The control unit 30 comprises a low speed control unit 31, a high speed control unit 32, and a speed compensation unit 33. The low speed control unit 31 includes a speed setting dial 31a that outputs a speed command signal according to an operation amount, a ramp waveform generation unit 31b that receives the speed command signal and generates a ramp wave according to the speed command, and a waveform generation. A deviation device 31c that takes a deviation between the output from the unit 31b and the stroke signal of the displacement gauge 16, an amplifier 31d that amplifies the deviation signal, and an adder that adds the speed compensation signal from the speed compensation unit 33 to the amplified deviation signal. 31e
It is composed of

The high speed control section 32 includes a speed setting dial 32a for outputting a speed command signal according to an operation amount and a servo valve signal setting section for receiving a speed command signal and setting a valve opening degree according to the speed command. 32b and servo valve signal setting unit 3
2b, and an adder 32c for adding the speed compensation signal from the speed compensating unit 33 to the output.

The speed compensator 33 includes a threshold value setting dial 33a for outputting a load threshold value according to the operation amount, a speed compensation setting dial 33b for outputting a speed compensation signal according to the operation amount, and a threshold value. A comparator 33c that compares the threshold value output from the setting dial 33a with the load detected by the load cell 15 and outputs a high level signal when the detected load exceeds the threshold value, and a contact a on the ground side normally And a switch 33d that is switched to the contact b on the speed compensation setting dial 33b side when a high level signal is output from the comparator 33c.

The operation of the high-speed impact tester constructed as above will be described. In the low speed impact test, a desired speed is set with the speed setting dial 31a. Speed setting dial 3
The speed command signal set by 1a is applied to the ramp wave generator 3
1b, the ramp wave generator 31b inputs a ramp wave signal corresponding to the speed command signal to the deviation device 31c. The deviation device 31c calculates the deviation between the ramp wave signal and the stroke signal from the displacement gauge 16, and the result is the amplifier 31d.
Is amplified by and is input to the adder 31e.

The load signal of the load cell 15 is a comparator 33c.
The comparator 33c outputs a low level signal until the load signal exceeds a threshold value which is one input of the comparator 33c. Therefore, the switch 33d is switched to the contact a side and the adder 31e Is added with a ground level speed compensation signal, that is, a zero signal. The output of the adder 31e is applied to the servo valve 14 as a servo valve signal, and the servo valve 14 is driven according to the applied signal. Servo valve 14
While the hydraulic oil is supplied to the hydraulic cylinder 12 by the above operation and the hydraulic cylinder 12 is accelerated, the impact force does not act on the sample by the running mechanism. Before the end of the run-up section, the speed of the hydraulic cylinder 12 becomes a constant speed state, and an impact force is applied to the test piece in the constant speed state.

When the load detected by the load cell 15 exceeds the threshold value, the comparator 33c outputs a high level signal and the switch 33d is switched to the contact b side. As a result, the speed compensation amount set by the speed compensation setting dial 33b is added to the adder 3
1e and added to the output signal of the amplifier 31d to form a servo valve signal. Therefore, the servo valve 12
The opening degree of is increased by the speed compensation signal, the flow rate of the hydraulic cylinder 12 is increased, the speed is increased, and the speed command set by the dial 31a is compensated. The magnitude of the speed compensation signal can be arbitrarily set by the speed compensation setting dial 33b.

On the other hand, in the high speed impact test, a desired speed is set by the speed setting dial 32a. The speed command signal set by the speed setting dial 32a is input to the servo valve signal setting unit 32b, and the servo valve signal setting unit 32b inputs a pulse signal according to the speed command to the adder 32c.
In the adder 32c, the speed compensation signal from the speed compensating unit 33 described above is added, but since the detected load does not exceed the threshold value immediately after the start of the test, the switch 33d is switched to the contact a side and the speed compensation signal is It is zero. Therefore, a pulsed servo valve signal output from the servo valve signal setting unit 32b is applied to the servo valve 14, the servo valve 14 suddenly reaches a predetermined opening, and the hydraulic cylinder 12 starts moving at a high speed. After the end of the run-up section, the hydraulic cylinder 12 gives an impact force to the test piece. When the load detected by the load cell 15 exceeds the threshold value, the switch 33d of the speed compensation unit 33 is switched to the contact b as described above, and the speed compensation signal set by the speed compensation setting dial 33b is input to the adder 31e. And added to the servo valve signal. Therefore, the opening of the servo valve 12 is increased by the speed compensation signal, the flow rate of the hydraulic cylinder 12 is increased, and the speed is compensated.

In such a high-speed impact tester, when the load acting on the test piece exceeds a threshold value after the impact force is applied to the test piece, the inflow rate of the hydraulic cylinder 12 increases. Therefore, the impact force is applied to the test piece and the hydraulic cylinder 12
Even if the speed decreases, the speed of the hydraulic cylinder 12 is compensated when the load exceeds the threshold value, and the test is continued at a speed closer to the desired speed set by the speed setting dial.

The high-speed impact tester is not limited to the type shown in FIG. 1, and is not limited to the embodiment as long as it is of a type that gives an impact force to the sample with an actuator. The present invention can be applied to a high-speed impact tester including only the low-speed controller 31 and a high-speed impact tester including only the high-speed controller 32. Further, the actuator is not limited to the embodiment, and various types can be used. As long as the impact force can be applied to the test piece at a constant speed, the type of the running mechanism does not matter, and an impact tester without the running mechanism itself may be used. Further, the speed compensation signal is added to the servo valve signal to increase the opening area of the servo valve 14, thereby increasing the flow rate and accelerating the hydraulic cylinder 12, but the opening area of the servo valve 14 is constant. It is also possible to increase the flow rate by increasing the circuit pressure of the hydraulic cylinder 12 as it is to perform speed compensation.

In the correspondence between the above embodiment and the claims, the hydraulic cylinder 12 is an actuator, the load cell 15 is a load detecting means, the speed compensator 33 and the adder 31e.
And 32c respectively constitute speed compensation means.

[0019]

As described above in detail, according to the high-speed impact tester of the present invention, the actuator is accelerated when the load exceeds the predetermined value after the impact force is applied to the specimen. The actuator can be driven at a desired speed even after the actuator gives an impact force to the sample.

[Brief description of the drawings]

FIG. 1 is a diagram showing an overall configuration of an embodiment of a high-speed impact tester according to the present invention.

[Explanation of symbols]

 10 High-speed impact tester main body 11 Table 12 Hydraulic cylinder 13 Specimen 14 Servo valve 15 Load cell 16 Displacement meter 30 Control part 31 Low speed control part 31a Speed setting dial 31b Ramp wave generating part 31c Deviation device 31d Amplifier 31e Adder 32 High speed Control unit 32a Speed setting dial 32b Servo valve signal setting unit 32c Adder 33 Speed compensator 33a Load threshold setting dial 33b Speed compensation setting dial

Claims (1)

[Claims] 1. A high-speed impact tester for applying a high-speed impact force to a specimen, an actuator driven at a speed according to a speed command, a load detection means for detecting a load acting on the specimen, and the detection. A high-speed impact tester, comprising: speed compensation means for increasing the speed of the actuator when the applied load is a predetermined value or more.