JPH02257031A - Impact testing device - Google Patents

Abstract

PURPOSE:To easily obtain a desirable impact strength to miniaturize and simplify a device and also to reduce a space by making an adjustment for an elastic force impressed on a buffer which receives a dropping energy from a stand for dropping by an extension and contraction of a coil spring capable of extending/contracting, when the strength for fragility of a product is tested. CONSTITUTION:When a measurement and evaluation of the strength for fragility of the product are executed, the test is required to be performed while changing variously the impact strength to be impressed to an object 14 to be tested. To satisfy this requirement, the impact strength is easily made to change by only rotating a motor 26, thereby a repeated filling/discharging of an expensive high-pressure gas for every time are made to be unnecessary. For this purpose, a table 5 mounted with the object 14 to be tested is freely dropped to the 1st piston 23 to make a highly rigid pad 7 to collide to the piston 23, and the generated impact wave is transmitted to the object 14 through a supporter 8 and the table 5. The elastic force for the coil spring 25 which is provided between the 1st piston 23 and 2nd piston 24 is adjusted by the motor 26 for making the impact strength to change variously.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to an impact testing device for testing the fragility strength of products.

[Prior art] Tests such as the fragility strength of products are carried out by actually allowing the specimen to fall freely onto a buffer that has been adjusted by applying a predetermined elastic force, and causing it to collide with the M tooth body. Tests were conducted by changing the elastic force of the shock absorber and establishing various setting conditions.

The impact test equipment for conducting such tests is as shown in Figure 2.
There was one shown in Figure 3. Figure 2 is a side view showing an example of the overall configuration of a conventional impact testing device on the market.
), (3) is a mount, (
4) is a guide rod, (5) is a table, (6) is an arrow indicating the moving direction of the table (5), (7) is a high-rigidity pad, (8) is a supporter that holds the pad (7), (9) )
is a shock wave generator, (10) is a high-pressure gas cylinder, (11)
) is the pressure indicator, (12) is the pressure regulating valve, (13) is the tube, (14) is the specimen to be tested, (15)
) is a holding plate for fixing the sample (14) to the chiffle (5), (16) is a fixing screw, and (17) is a nut.

As shown in Figure 2, Kaitrot (4) is attached to the mount (
3), the table (5) is adapted to move up and down along the guide rod (4) as shown by the arrow (6), and is lifted to a predetermined height by a lifting device (not shown). It is locked and held at that height by a retainer (not shown).

In addition, a high-rigidity pad (7) is provided at the lower end of the table (5) via a sabota (8), and a piston (19)
This prevents the generation of harmonics when it collides with the

FIG. 3 is a partial sectional view showing the structure of the shock wave generator (9) shown in FIG. 2, where the same reference numerals as in FIG. piston,(
20) is a gasket, (21) is an arrow indicating the direction in which the piston (19) slides within the cylinder (18), (22)
indicates the cylinder volume.

As shown in FIGS. 2 and 3, a screw (1) fitted with a gasket (20) for preventing waste leakage is provided inside the cylinder (18), and the arrow (21) Slide inside the cylinder (18) as shown in . This piston (
The cylinder volume (22) on the lower side of 19) is filled with high pressure gas (nitrogen gas, which is an inert gas for boat fishing), so there is a tube tube 3 whose tip is connected to a high pressure gas cylinder O). ) are connected.

The gas pressure in the cylinder volume <22) is adjusted by the pressure regulating valve 2), and by filling the cylinder volume (22) with high-pressure waste adjusted to a predetermined pressure, the gas pressure is adjusted to the piston (19). moves to the upper end of the cylinder drum 18), and the piston (one) is biased by a predetermined elastic force adjusted by gas pressure.

Next, the operation will be explained. First, the table (5) is moved to a predetermined height using a lifting device and is locked and held at that height. Next, in order to provide a preset impact strength, the cylinder volume (22) is filled with dregs at a predetermined pressure, and a predetermined elastic force is applied to the piston (18).

Next, the table (5) to which the sample (14) is attached is allowed to fall freely onto the screws 1 to (19), and the high-rigidity pad <7 is caused to collide with the piston (19). The shock wave generated by this collision is transmitted to the specimen (14) via the sabot 8) and the table (5), giving an impact to the specimen (14).

When the high-rigidity pad (7) collides with the piston (19), the chifur (5) is rebounded by the piston (19) and rises, and then falls again. The raised table (5) is held in the raised position by a brake machine WI (not shown) so as not to collide with the piston (19>).

Figure 4 shows the load applied to the table <5) and the table (5) when the high-rigidity pad <7) collides with the piston (19).
). In (a), the piston (14) has not yet been displaced at the initial stage of the collision, and the table (
5) The amount of displacement is only due to the elasticity of the high-rigidity pad (7) and the zabota (8). In (b), the elastic force of the piston <19) given by the gas pressure is defeated by the kinetic energy of the table (5), and the piston <19)
is descending.

(b') and (a') do not show the stage where the kinetic energy of the table (5) becomes 0 and is bounced back by the waste pressure and rises again. Furthermore, if the behavior of these tables (5) is considered as an impact acceleration generated in the table (5), an impact acceleration waveform not shown in FIG. 5 will be obtained. The reason why the impact acceleration waveform becomes trapezoidal with a chevron in the center as shown in Fig. 5 is because the piston (19) descends.
This is caused by an increase in gas pressure caused by compressing the gas filled in the cylinder volume (22).
For this reason, the inner diameter of the cylinder (18) is increased to approximate the ideal waveform as shown in FIG. 6.

When actually measuring and evaluating the fragility strength of products using such conventional impact testing equipment, it is necessary to
4) It is necessary to conduct the test while variously changing the impact force applied to the cylinder, and therefore the test is repeatedly performed while appropriately changing the gas pressure of the gas filling the cylinder volume (22).

[Problems to be Solved by the Invention] The conventional impact testing apparatus described above has the composition described above, so when trying to change the impact strength applied to the test object, high pressure is applied each time. It is necessary to repeatedly fill and discharge the waste, which causes high consumption of high-pressure gas and increases costs, and there are other problems such as requiring a large installation space for installation and storage in the phone.

As a way to solve this problem,
There is a prior art published in Publication No. 33852 [Drop Impact Tester J]. This prior art uses a cushioning body such as rubber as a means for applying elastic force, and by changing the effective length of this IIJT body, the spring constant k is changed, but the height h of the impacting body However, there was a problem in that the relationship between the spring constant and the spring constant became complicated.

This invention was made to solve the above problems, and it is possible to reduce costs by not using high-pressure gas, to reduce the cost by making it compact and simple, and not require a large installation space, and to improve the bounce constant of the shock absorber. The aim is to obtain an impact test device that can be set directly and accurately.

[Means for Solving the Problems] The impact test device according to the present invention uses a coil spring to apply elastic force to a buffer body that receives the falling energy of a falling table, and a drive device causes the coil spring to expand and contract. We decided to create a structure that is possible.

[Operation] In this invention, a coil spring is used to bias the elastic force given to the shock absorber that receives the falling energy of the falling table, and this coil spring has a structure that can be expanded and contracted by the drive device. By changing the elastic force applied to the shock absorber, it is possible to select a desired impact strength.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings. 1st
The figure is a sectional view showing an embodiment of the present invention, and the same reference numerals as in FIGS. 2 and 3 indicate the same or corresponding parts.
9A) is the shock wave generator in this example, (23)
(24) is the second piston, (25) is the coil spring, (26) is the motor,
(27) is a feed male screw, (28) is a feed female screw, (29)
) is an arrow indicating the sliding direction of the first piston (23), (
30) is an arrow indicating the sliding direction of the second screws 1 to (24), and (31) is an arrow indicating the rotating direction of the male feed screw (27).

As shown in FIG. 1, the shock wave generator (9A) in this embodiment is equipped with a second piston (24), and the center of the second piston (24) has a female feed screw (28).
) is cut, and this female feed screw (28) has a male feed screw.
27) are fitted. By rotating the motor (26), the male feed screw (27) rotates in the direction shown by the arrow (31), causing the second piston (24) to slide in the direction of the arrow (30). In addition, a coil spring (25) having an elastic force is sandwiched between the second screws 1 to 24), and the first screws 1 to 24) serve as shock absorbers that collide with the high-rigidity pad (7).
A first piston (23) is provided.
is elastically biased by a coil spring (25), and is always pushed up and positioned above the cylinder (]8).

Next, the operation will be explained. First, the dople (5) is moved to a predetermined height using the lifting device and is locked and held at that height. Next, in order to apply a preset impact strength, the power is turned on and the motor (26) is rotated.
The elastic force applied to the piston (23) by the coil spring (25) is adjusted.

That is, by rotating the motor (26), the male feed screw (27) is rotated, and the second piston (24) having the female feed screw (28) fitted to the male feed screw (27) is rotated.
) is slid upwardly or downwardly within the cylinder (18).

When this second piston (24) is slid upward,
By compressing the coil spring (25), the elastic force applied to the first screws 1 to (23) becomes stronger, and the impact strength when the high-rigidity pad (7) collides can be increased. .

Conversely, when the second piston (24) is slid downward, the expansion of the coil spring (25) is relaxed,
The elastic force applied to the first screws 1 to (23) is weakened, and the impact strength when the high-rigidity pad (7) collides can be reduced. (If the elastic force is 1 〇 - F, the spring constant is K, and the shrinkage rate of the spring is D, then F-
(K/D relationship).

Therefore, by rotating the motor (26), the elastic force biasing the coil spring (25) or the first screw (23) can be easily changed, and the desired impact strength can be easily set. ·be able to.

Thereafter, as with the conventional device, the table (5) with the sample (14) attached is allowed to fall freely onto the first screw 1 hem (23), and the highly rigid bat (7) is placed between the first screws 1 to 1. (23)
to collide with. The shock wave generated by this collision is transmitted to the specimen (14) via the supporter (8) and the table (5), and gives an impact to the specimen (14).

When actually measuring and evaluating the fragility strength of a product, it is necessary to conduct the test while varying the impact strength applied to the sample (14). Now, the impact strength can be easily changed by simply rotating the motor (<26), and there is no need to repeatedly fill and discharge expensive high-pressure gas each time as in conventional devices. No longer needed.

Although the above embodiment describes the case where a trapezoidal impact acceleration waveform is generated, it is possible to generate various impact acceleration waveforms by changing the characteristics of the coil spring.

[Effects of the Invention] As explained above, the present invention has a structure in which a coil spring is used to bias the elastic force applied to the buffer body that receives the falling energy of the falling table, and the coil spring is expanded and contracted by the drive device. By directly and accurately setting the spring constant of the shock absorber, the elastic force biasing the shock absorber can be easily changed, and the desired impact strength can be easily selected. In addition, costs can be reduced, and the device can be made smaller and simpler, so that it does not require a large installation space.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention, FIGS. 2 and 3 are views showing a conventional device, and FIGS. 4 to 6 are views for explaining generated impact acceleration waveforms. <1) is the floor, (2) is the M member, (3) is the mount, (4
) is a kite rod, (5) is a chifur, (7) is a high rigidity para 1, (8) is a supporter, (9A) is a shock wave generator, (14) is a sample, (15) is a holding plate, (16)
is the fixing screw, (17) is the nut, (23) is the first piston, (24) is the second piston, <25) is the coil spring, (26) is the motor, (27) is the feed male screw, (28)
) is a female feed screw. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] A drop table on which a test object is placed is dropped onto a buffer body biased with elastic force, and the fall energy of the drop base pushes down the buffer body, and the elastic force biased on the buffer body is lowered. An impact test device that tests the test object by applying a shock wave generated by force to the test object, which includes a coil spring for applying an elastic force to the shock absorber, and a coil spring for expanding and contracting the coil spring. a driving device, the driving device is driven to change the elastic force biasing the buffer body, and change the impact strength received by the drop table when the drop table falls onto the buffer body. Characteristic impact test equipment.