JPH11304680A - Impact tester - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable the impact force measurement of a light and small object to be tested by processing signals from photodetectors obtained at the time when the object to be tested passes through two band-shaped parallel light and collides with a collision plate, measuring the time difference of passage, and computing an impact force. SOLUTION: The collision between an object to be tested 7 and a collision plate 6 occurs simultaneously with the complete passage of the object to be tested 7 through two band-shaped parallel light according to the location adjustment of a displacement detector 10 performed in advance. The object to be tested 7 is bounced after collision and starts to move in the opposite direction. Then by inputting signals obtained from the first and second photodetectors to an analyzing device 20, it is possible to measure the difference t1 between the first rise time of the output signals of the first and second photodetectors, the time t2 during which the output signal of the second photodetector continues to be of a maximum amplitude from the first rise, and the difference t3 between the fall time of the second photodetector and the fall time of the first photodetector. As a result, it becomes possible to obtain various amounts on the impact of the object to be tested by the analyzing device 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an impact tester having a function of measuring the speed, impact action time and magnitude of an impact before and after a collision, particularly when the specimen is small and light. The present invention relates to an impact tester that is highly effective.

[0002]

2. Description of the Related Art Conventionally, as a method of applying an impact in an impact tester, a method of hitting a test object with a swung hammer and a method of applying an impact by free fall of a member to which the test object is attached are known. .

[0003] A hammer impact tester usually carries out a test by attaching an acceleration pickup to an object to be measured in order to simultaneously measure the magnitude of the impact. Further, in an impact tester using a free fall of a member to which a test object is attached, the magnitude of impact is measured using an acceleration pickup attached to the member.

[0004]

In order to accurately measure the magnitude of the impact, it is desirable to attach the acceleration pickup directly to the DUT. However, in a hammer impact tester, the mass of the acceleration pickup is equal to the mass of the DUT. On the other hand, if it cannot be neglected, the impact given by directly attaching the acceleration pickup differs from that of the test object alone. Therefore, it is difficult to accurately grasp the magnitude of an impact given to a small or light test object using a hammer impact tester.

In an impact tester utilizing the free fall of a member to which a DUT is attached, even if the DUT is small and light, the accelerometer can be mounted on that member without any problem. Problems arise in fixing the specimen. In other words, it is necessary that the acceleration pickup is fixed on the DUT, but in this method, a member is interposed between the DUT and the acceleration pickup. Impacts are different. Further, when the test object does not have a hole for fixing to the member, the difference becomes larger. Often, a fixing method using an adhesive is adopted, but in that case, it is impossible to reuse the test object.

In view of the above, it is an object to measure the magnitude of the impact on a light and small test object which cannot be subjected to an impact test by directly attaching an acceleration pickup.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method and an apparatus for measuring the magnitude of an impact even on a light and small test object.

[0008]

According to the present invention, a base plate, a support fixed to the base plate, a bearing attached to a tip of the support, a rotatable arm fitted to the bearing, and a cover attached to the tip of the arm. A stage on which a test object can be mounted, a collision plate arranged so that the test object causes a collision when the arm rotates and comes in a vertical direction, and when the test object collides with the collision plate A light source that emits the above-mentioned two strips of parallel light arranged so as to pass through exactly two strips of parallel light, two photodetectors that detect light from the light sources, and the photodetector An analyzer that calculates the magnitude of the impact by processing the signal from and measuring the time difference,
And a display for displaying the result.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a side view of an impact tester having a speed measuring device constructed based on the principle of the present invention. The impact tester mainly consists of base plate 1 and base plate 1
, A bearing 3 installed on the top of the support 2, and an arm 4 having a rotating shaft fitted to the bearing 3.
A stage 5 on which the DUT 7 mounted on the tip of the arm 4 is placed, a collision plate 6 fixed to the base plate 1,
An arc plate 8 for fixing the arm 4 at an arbitrary angle, a fixing release device 9 that can move on the arc plate 8 and temporarily fix the arm 4, and for examining the movement of the DUT 7. A displacement detector 10, an analyzer 20 for processing the signal from the displacement detector 10 to obtain the speed of the DUT and the magnitude of the impact received, a display 21 for displaying the analysis result, A position adjuster 22 that enables fine adjustment of the position of the detector 10.

The configuration of the displacement detector 10 will be described with reference to FIG. The displacement detector 10 includes a light source 11 that emits two strip-shaped parallel lights that are long in the vertical direction, and a first light detector 12 and a second light detector 13 that separately detect the two parallel lights. I have. The light source 11, the first photodetector 12, and the second photodetector 13 are arranged so as to face each other, and are adjusted in the height direction so that the test object passes two strip-shaped parallel lights.

Next, the operation of the impact tester having the above configuration will be described.

First, preparations before conducting an impact test will be described. The DUT 7 is placed on the stage 5 with the arm 4 hanging down in the vertical direction. At this time, the DUT 7 comes into contact with the collision plate 6, and the position detector 22 controls the displacement detector 10.
Is slowly moved from right to left in FIG. Since the first photodetector 12 does not detect the DUT 7 at first, its output signal has the maximum amplitude. When the DUT 7 is detected, its output signal starts to decrease. Immediately before starting to decrease, the movement of the displacement detector 10 is stopped.

Next, the arm 4 is lifted to a predetermined angle and temporarily fixed by the fixing and releasing device 9, and when the fixing is released, the arm 4 starts rotating and the DUT 7 starts rotating at the same time.

A first light detector 12 and a second light detector 13
Will be described with reference to FIG. The arm 4 is gradually accelerated by gravity. At this time, the first photodetector 1
The second and second photodetectors 13 exhibit the largest amplitude since there is nothing blocking them before them.

Then, when the device under test 7 approaches the strip parallel light incident on the second photodetector, the amplitude of the second photodetector 13 starts to decrease. Further, when the stage 5 starts to be hit by the above-mentioned band-shaped parallel light, the amplitude of the second photodetector 13 further decreases and shows the minimum amplitude.

As the arm 4 further advances, only the DUT 7 blocks the above-mentioned band parallel light, and the output signal of the second photodetector 13 slightly increases. As the arm 4 further advances, the DUT 7 completely passes, and the output signal of the second photodetector 13 returns to the original maximum amplitude again.

The strip parallel light incident on the first photodetector 12 is different from the strip parallel light incident on the second photodetector 13 in FIG.
Is slightly shifted to the left, the second photodetector 1
The same change as the change of the signal of No. 3 appears slightly later in time.

At the same time as the test object 7 has completely passed through the two parallel beams of light, the test object 7 and the collision plate 6 collide with each other in accordance with the previously performed adjustment of the position of the displacement detector 10.
The impact action time of the impact plate 6 on the DUT 7 varies depending on the material of both, but the impact plate 6 made of Teflon and the DUT 7 made of brass used this time were about several hundred microseconds. During this shock operation time, the output signals of the first photodetector 12 and the second photodetector 13 remain at the maximum amplitude.

Since the arm 4 and the stage 5 are designed so as not to collide with the collision plate 6, after the collision between the DUT 7 and the collision plate 6, the previous rotary motion is continued. DUT 7
Bounces off after the collision and begins to move in the opposite direction. Since the friction between the contact surface of both the stage 5 and the DUT 7 is very small, the force that hinders the bouncing motion of the DUT 7 is very small and has little effect.

Therefore, as soon as it bounces, it starts to block the band parallel light incident on the first photodetector 12, and the output signal of the first photodetector 12 starts to decrease. Test object 7
Has passed through the above-mentioned band parallel light, the output signal of the first photodetector 12 returns to the maximum amplitude.

The change in the output signal of the second photodetector 13 is as follows:
This time, the same change as the change in the output signal of the first photodetector 12 appears slightly later in time.

As described above, a signal as shown in FIG. 3 is obtained. When these signals are input to the analyzer 20, when the time is tracked from when the arm 4 is released, the first rising time of the output signal of the first light detector 12 and the first rising time of the second light detector 13 T2, which is the difference between the rising times, and the time t2, at which the output signal of the second photodetector 13 continues to have the maximum amplitude since it first rises,
Photodetector 13th fall time and first photodetector 1
It is possible to measure t3, which is the difference between the falling times of the two.

Since t1 is the transit time of the two parallel strips of light, the speed v1 immediately before the collision of the test object 7 can be calculated by dividing the interval d between the two parallel strips of light by the t1. it can. It is preferable that the interval between the strip-shaped parallel lights is smaller because the value becomes closer to the instantaneous speed. This time, an interval of 1 mm was used. Similarly, by dividing the d by the t3, the DUT 7
Immediately after collision v2 can be calculated.

In the collision between the Teflon collision plate 6 and the brass DUT 7 used in this case, it is known that the acceleration change of the DUT 7 is a triangular wave as shown in FIG. Assuming that the peak value of the acceleration is Ap, the impact action time is the above-mentioned t2, and thus the integral of the triangular wave, that is, the area is the change in speed given to the DUT 7.

From this, the peak value of acceleration Ap is given by the following equation:
p = 2 × (v2−v1) / t2.
In this way, it is possible for the analyzer 20 to determine various quantities relating to the collision of the test object.

It is possible to calculate the magnitude of the impact even when the impact plate 6 and the DUT 7 are made of a material other than Teflon and brass. For example, when a rubber collision plate 6 and a test object made of carbon steel are used, the waveform of the acceleration becomes a half sine wave. At this time, the peak value Ap of the acceleration is expressed by the formula Ap =
(Π / 2) × (v2−v1) / t2.

The time from t1 to t3, which is the result of analysis by the analysis device 20, the speed v1 immediately before the collision, the speed v2 immediately after the collision, and the peak value Ap of the acceleration are displayed simultaneously or switched by the display 21. Is possible. When these displayed numerical values are taken into a personal computer as needed, data management can be performed.

In this case, the strip-shaped parallel light is used. However, a narrow beam may be used as long as the light can be appropriately applied to the test object.
Further, the same effect can be expected even if the displacement detector is constituted by a light source that emits one light beam and a photodetector provided with a mask having an opening having the same shape as the above-mentioned strip-shaped parallel light or a narrow beam.

[0029]

According to the method of the present invention, since the measurement can be performed in a non-contact manner, the magnitude of the impact can be measured by avoiding the influence of the increase in the mass of the DUT by mounting the acceleration pickup. It is possible to Further, according to the method of the present invention, it is not necessary to fix the object to be measured to the jig, and the preparation for measurement is completed by a simple procedure of merely mounting the object on the stage. Furthermore, the behavior of the test object at the time of collision can be monitored by a displacement detector, and the velocity before and after the collision and the duration of impact can be measured.

[Brief description of the drawings]

FIG. 1 is a side view of an impact tester according to an embodiment of the present invention.

FIG. 2 is a top view of the displacement detector according to the embodiment of the present invention.

FIG. 3 is a conceptual diagram illustrating an output signal of a first photodetector and an output signal of a second photodetector according to the present invention.

FIG. 4 is a conceptual diagram illustrating a change in acceleration applied to a test object during an impact test according to the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 base plate 2 support 3 bearing 4 arm 5 mounting table 6 collision plate 7 DUT 8 arc plate 9 fixing release device 10 displacement detector 11 light source 12 first photodetector 13 second photodetector 20 analysis device 21 Display 22 Position adjuster

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor, Michida Michiyasu, 840 Takeno, Shimotomi, Tokorozawa-shi, Saitama Citizen Watch Co., Ltd. 840 Takeno Citizen Watch Co., Ltd.

Claims (1)

[Claims] 1. A base plate, a support fixed to the base plate, a bearing attached to a tip of the support, a rotatable arm fitted to the bearing, and a test object mounted on the tip of the arm. A stage, a collision plate arranged so that the test object causes a collision when the arm rotates and comes in the vertical direction, and just two strips of parallel light when the test object collides with the collision plate A light source that emits the above-mentioned two strips of parallel light arranged so as to finish passing, two photodetectors that detect light from the light source, and a signal from the photodetector are processed to determine a time difference. It consists of an analyzer that calculates the magnitude of the impact by measuring it, and a display that displays the result.
When passing through two parallel strips of light and colliding with the collision plate, the difference between the transit time of the DUT immediately before the collision and the passage of the DUT immediately after the collision is determined from the output waveform of the photodetector that detects the two parallel strips of light. The time difference and the impact action time are obtained, the speed immediately after the collision and the speed immediately before the collision are calculated from the time difference and the interval between the parallel strips of light, the difference between the speed immediately after the collision and the speed immediately before the collision is obtained, and the result is doubled. And an impact tester for calculating the magnitude of the impact on the DUT by dividing the value by the impact action time.