JPS5933852B2 - Drop impact tester - Google Patents

Description

[Detailed Description of the Invention] [1] Technical field The present invention is directed to dropping a drop table on which test samples such as various products are placed onto an elastic buffer made of rubber, plastic, etc. This invention relates to a drop impact tester that applies impact to a product under the required test conditions.

[2] Prior art In this type of testing machine, it is usually required to apply a half-sine wave shock waveform to the specimen, so the above-mentioned buffer is used to generate the half-sine wave. It is used as a means.

On the other hand, this type of testing machine is required to be able to arbitrarily change the magnitude of the impact acceleration and the impact duration (width of the pulse) as test conditions.

However, in conventional testing machines of this type, when the weight and falling height of the specimen are constant, - - ・ ・
----1, 1, 1, 1, 1, 10, 10, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, and 10, and the impact duration (width of the pulse) is uniquely determined.

Therefore, in order to obtain various different impact durations, it is necessary to prepare a large number of shock absorbers with different hardnesses and dimensions, and to replace these five shock absorbers one by one according to the required impact duration. It was necessary to stack shock absorbers of different hardness. For this reason, the task of creating the required test conditions (impact acceleration magnitude and impact action time) each time the weight of the specimen changes is extremely troublesome and takes a long time. Ta.

[3] Purpose of the Invention The present invention has been made in order to eliminate the above-mentioned conventional drawbacks, and its purpose is to provide a drop impact tester that can extremely easily and quickly create required test conditions. do.

[4] Structure of the Invention The drop impact tester according to the present invention is a drop impact tester that applies an impact to the test sample by dropping a drop table on which the test sample is placed onto a buffer, A cylindrical body fitted to the outer periphery of the buffer body so as to be movable in the vertical direction with respect to the buffer body, and a cylindrical body lifting device for raising and lowering this cylindrical body, the cylinder body By raising and lowering the cylindrical body 25 using a lifting device and changing the effective height of the shock absorber, the spring constant of the shock absorber and, by extension, the impact action time can be arbitrarily changed.

[5] Examples Hereinafter, the present invention will be explained in more detail based on examples shown in the drawings.

1 to 3 show embodiments of the present invention.

In this embodiment, the tester main body 1 has a gate shape, and on the bottom of the tester main body 1 there is a buffer frame 2.
is installed. An anvil 3 is attached to the 35 frame 2, and a cylindrical buffer body 4 made of an elastic material such as rubber or plastic is mounted on the anvil 3 with its axis directed in the vertical direction. 0 placed
On the outer periphery of the buffer body 4, a cylindrical body 5 made of steel is provided.
It is fitted into the buffer body 4 so as to be movable in the vertical direction.

A pair of internally threaded bodies 6 are attached to the lower end of the cylindrical body 5 at positions that are 180 degrees apart from each other. - On the other hand, a pair of feed screws 7 are rotatably supported in the vertical direction on the frame 2.
A female screw body 6 is screwed into each of the .

Further, a pair of stepping motors 8 are attached to the frame 2, and gears 9 attached to the rotating shafts of these motors 8 are connected to gears 10 attached to the upper end of each feed screw 7. Each is interlocked. In this embodiment, the female threaded body 6, the feed screw 7, the stepping motor 8, and the gears 9, 10
The cylindrical body lifting device is constructed by the above. A hoist 11 is attached to the upper part of the testing machine main body 1, and an electromagnetic hook 13 is attached to the lower end of a chain 12 of this hoist 11.

Further, the testing machine main body 1 is adapted to guide the drop table 14 in the vertical direction above the buffer body 4, and the electromagnetic hook 13 is adapted to be attached to and detached from the soil part of the drop table 14. It's happening. Next, the operation of this embodiment will be explained.

When conducting a test, the sample 15 is placed on the drop table 14, and the hoist 11 lifts the drop table 14 together with the sample 15 to a certain height.
3 to separate the drop table 14.

As a result, the drop table 14 is moved to the buffer body 4 along with the sample 15.
The specimen 15 is dropped onto the top and is subjected to an impact at a certain impact acceleration and impact duration. Here, in this drop impact tester, when the stepping motor 8 is driven and the feed screw 7 is rotated via the gears 9 and 10,
The cylinder body 5 moves up and down, and the effective height He of the buffer body 4 (buffer body 4
(the height at which the shock absorber 4 is exposed from the cylinder 5) and, in turn, the spring constant of the buffer body 4 can be changed. In this way, an arbitrary impact action time can be obtained. Next, this will be explained in more detail.

Now, assuming that the elasticity of the buffer body 4 has a linear characteristic, 4C.Here, assuming that the cylinder body 5 does not exist, the spring constant k is determined by the shape, size, and longitudinal elastic modulus of the buffer body 4. However, when the buffer body 4 is cylindrical as in this embodiment, the spring constant k is determined by the following equation.

V) 1 ψRlC'l: J (\V1ν) Here, the longitudinal elastic modulus E can be adjusted by adjusting the composition of the raw materials.

Also, for reference, the hardness of commonly used rubber Hs (spring type hardness tester JISK63Ol)
The relationship between E and the longitudinal elastic modulus E is expressed by the following equation. As is clear from equation (2), when d and E are constant, the buffer 4
In order to change the spring constant k of , it is sufficient to change the height h, but in an incompressible elastic material such as rubber, the difference between the longitudinal elastic modulus E and the transverse elastic modulus G is E= It has something to do with 3G.

That is, within the elastic limit, the ratio of longitudinal strain to transverse strain, that is, Poisson's ratio m, is constant. Therefore, in this test machine, the outer periphery of the buffer body 4 is restrained by the cylinder body 5. The portion of the cylindrical body 5 can hardly be deformed not only in the horizontal direction (radial direction) but also in the vertical direction (axial direction), and only the portion of the effective height He exposed from the cylinder 5 can be deformed both vertically and horizontally. can also be freely transformed.

Therefore, in this test machine, the effective height He is (2)
Approximate h in Eq.

That is, there is a relationship expressed by the following equation between the spring constant k1, the total weight WCkg of the weight WO of the sample 16, and the weight W1 of the drop table 14, and the impact action time D[s].

However, g: gravitational acceleration, 980C77! /S2 Also,
Falling height of sample 15 H1 Spring constant k1 Impact acceleration G (
There is a relationship between the gravitational acceleration (multiple of gravitational acceleration g) and the total weight W of the sample and the dropping platform as shown in the following equation.

Therefore, the weight W of the sample 15.

By giving the required impact action time D to the equation (5), the spring constant k of the shock absorber 4 required in that case can be obtained, and by further giving the spring constant k to the equation (4), in that case The effective height He of the buffer body 4 to be set is determined. Furthermore, by giving the required impact acceleration G to equation (6), the fall height H that should be set in that case can be determined. Then, the stepping motor 8 is rotated by the amount by which the effective height He of the buffer body 4 becomes the value determined as described above, and the stepper motor 8 is rotated by the value of the falling height H determined as described above. Drop platform 1 by hoist 11
4 and dropping the drop table 14 onto the buffer body 4 from this state, the required impact acceleration G and impact action time D can be obtained.

In this way, in this test machine, the spring constant of the buffer body 4 is
Since it is possible to change the temperature over a wide range by simply raising and lowering the cylindrical body 5 without replacing or stacking the buffer body 4, the required test conditions can be created extremely easily and quickly.

In conjunction with this, the computer also records the weight W of the sample 15. , manually input the required impact acceleration G1 and the required impact duration D, and have the same computer calculate the falling height H1 of the sample 15 and the effective height He of the buffer body 4 corresponding to these manual inputs, and A test machine is installed on the same computer, and the falling height H1 of the sample 15 and the effective height He of the buffer body 4 are
By controlling the value to be the calculated value, it becomes possible to automatically and continuously perform drop impact tests under various test conditions. [6] Effects of the Invention As described above, the impact drop tester according to the present invention allows the required test conditions to be created extremely easily and quickly by making it possible to change the spring constant of the shock absorber by raising and lowering the cylindrical body. It is possible to obtain excellent effects such as:

[Brief explanation of the drawing]

Fig. 1 is a front view showing an embodiment of a drop impact tester according to the present invention, Fig. 2 is a longitudinal sectional view showing the main parts of the embodiment, and Fig. 3 is a plan view showing the main parts. ...Buffer body, 5...Cylinder body, 6...Female screw body,
7...Feed screw, 8...Stepping motor, 9, 10...Gear, 1155 hoist, 12...Chain, 13... ...Electromagnetic hook, 14...Drop table, 15...Test sample.

Claims (1)

[Claims] 1. In a drop impact testing machine that applies an impact to the sample by dropping a drop table on which the sample is placed onto a buffer, a test piece is placed on the outer periphery of the buffer in the vertical direction with respect to the buffer. A drop impact tester comprising a cylinder fitted in a movable state and a cylinder lifting device for raising and lowering the cylinder.