JPS5972044A - Measuring device of dynamic spring constant - Google Patents

Abstract

PURPOSE:To ensure high-precision load measurement, by arranging a sound shielding material between an exciting shaft and an attaching part of a load detector and cutting off the propagation of an acoustic energy generated from an oscillation generating machine to said attaching part. CONSTITUTION:A sound shielding material 15 is arranged between an exciting shaft 5 of an oscillation generating machine 1, which excites a test piece 11, and an attaching part 10 of a load detector 9 which detects the load applied to said test piece 11. By this constitution, the sound shielding material 15 cuts off the propagation of said acoustic energy to the attaching part 10 to prevent the generation of acceleration of the detector 9. As the result, the excitation of the attaching part 10 due to said energy is not generated, and consequently, the generation of acceleration of said detector is prevented to ensure the load measurement of very high precision.

Description

[Detailed description of the invention] The present invention relates to a dynamic spring constant measuring device.

Generally, this type of device vibrates a test piece with a vibration generator, detects the load applied to the test piece at this time with a load detector, and measures the dynamic spring constant of the test piece from the detection result. . However, in the conventional device, various vibrations caused by the drive of the vibration generator generate acceleration in the load detector, which causes an error in the load measurement by the detector. Ta.

The present invention solves the above-mentioned problems, and provides a dynamic spring constant that prevents the acceleration of the load detector caused by the various vibrations mentioned above, especially the acceleration caused by acoustic energy, and makes it possible to measure loads with extremely high accuracy. The purpose is to provide a measuring device. Therefore, a feature of the present invention is that a sound insulator is disposed between the vibration axis of the vibration generator that vibrates the test piece and the mounting part of the load detector that detects the load applied to the test piece. Accordingly, the acoustic energy generated from the vibration generator is prevented from propagating to the mounting portion, thereby preventing the generation of acceleration of the detector due to the energy.

The present invention will be described in detail below based on the embodiments shown in the drawings. Explain.

In FIGS. 1 and 2, (A) t/'i is a downward vibration type dynamic spring constant measuring device in which a vibration generator (1) is directed downward; The frame (3) is fixed to the foundation (2) via the guide bearing (6).
It is supported by the guide shaft (4) so that it can be raised and lowered freely.

The pedestal (3) is approximately U-shaped from the front, and the guide shaft (4) serves as a support part (force (8)) for the vibration generator (1) on both left and right sides of the pedestal (3).
)... is fixedly installed. In addition, the center is the mounting part (II) of the load detector (9).
) is placed on the pedestal α■ by the mounting member as shown in Fig. 7 so that its center coincides with the axis of the excitation shaft (5) of the vibration generator (1).
The test piece αυ is coaxially held between the detector (9) and the excitation shaft (5).

In addition, the test piece 0 is placed on the upper surface of the detector (9) as shown in FIG.
The catch seat a→ for placing υ is fixed and fixed. Therefore, the vibration generator (1) is driven to move the vibration shaft (5) up and down (
The test piece αυ is vibrated by vibration in the Q (to) direction, and the load applied to the test piece at this time is detected by a load detector (9).
Detected by.

The Q proverb is a balance weight screwed to the side of the right support part (8) of the pedestal (3), and the left and right support parts (
7) By balancing (8), the vibration of the left and right support parts (7) (8) caused by the vibration generator (1) E motion is detected by the detector (9).
The structure is designed so that it does not adversely affect the measurement accuracy. That is,
In the downward vibration type measuring device (8) shown in the figure, the detector (9) is fixed to the mounting part 00 of the pedestal (3) as described above. part ac
When h vibrates, it causes an acceleration in the detector (9), which causes the detector (9) to generate a load signal corresponding to the load to be measured, as well as a combination of said acceleration and the equivalent mass of the detector (9). A load signal corresponding to the product is also output at the same time, which causes an error in the load measurement. On the other hand, the vibration generator (1) is provided with a vibration isolation mechanism such as an air spring between the vibration generator (1) and the pedestal (3) to provide some measure of vibration isolation. However, if there is a deviation from the axis of the test specimen 01) or deviation from the axis of the excitation force generating mechanism (not shown) of the vibration generator (1), these may become factors. , the reaction force that the vibration generator (1) receives from the test piece α1) when it is driven causes the generator (1) to generate not only an axial movement but also a rotational movement around the center of gravity (G). That will happen. The rotational moment of this rotational motion becomes a force that moves the guide shaft (4) in the left and right (Q) direction as shown in Fig. 3, and this causes the mount (
3) exhibits a five-pronged vibration mode due to its resonance frequency, as shown in the figure. Note that this vibration mode was measured by detecting vibrations at points (old υ and (C)) of the pedestal (3) in FIG. 3 (the same applies hereinafter).

However, this vibration mode is often not completely symmetrical. This is because the vibration mode due to the resonance frequency of the left support part (7) and the vibration mode due to the resonance frequency of the right support part (8) do not match, and normally these modes are shown in Figures 4 and 5, respectively. It often looks like the picture. This mode discrepancy is caused by a machining error during the manufacture of the mount (3), and such lateral imbalance causes the mounting members to vibrate, significantly reducing the measurement accuracy of the detector (9) as described above. This will result in a decrease in Therefore, as shown in Fig. 6, a balance weight Q'4 of the weight necessary to eliminate the above-mentioned machining error is placed at the required location (in the case shown, the right support part (8)).
By attaching it to the side surface position), it eliminates the left and right resonance frequency unbalance and makes the vibration mode completely symmetrical between the left and right sides, which reduces the vibration generation of the mounting part a1 and, by extension, the detector (
9) is prevented from occurring in order to prevent the measurement accuracy of the detector (9) from deteriorating.

The flat plate 6051 is a sound insulator for preventing a decrease in the measurement accuracy of the detector (9), similar to the above-mentioned balance weight σ. That is, when the vibration shaft (5) of the vibration generator (1) vibrates, a strong sound is generated in synchronization with the vibration frequency. The acoustic energy caused by this sound is propagated to the mounting part σO having a relatively wide horizontal surface and excites the mounting part 00, and as described above, the detector (
9) generates acceleration, resulting in an error in the load measurement. Therefore, if a sound insulating body α9 is arranged between the vibration axis (5) and the mounting part (tJ), the sound insulating body α9 blocks the propagation of the acoustic energy to the mounting part aCt, and the detector (9 )
It is possible to prevent the generation of acceleration and to prevent a decrease in measurement accuracy. Specifically, as shown in FIG. 7, the sound insulating body α is constructed by mounting and fixing the sound insulating plate OQ on the mounting portion Qo via a mounting piece having a vibration isolating member αη. It is. The sound insulating plate αQ is made of a sound insulating material or a sound absorbing material, for example, as shown in FIG. It has a flat plate shape that covers almost the entire mounting part qO.

FIG. 9 shows a second embodiment of the present invention, and shows a dynamic spring constant measuring device (CB) of a two-way vibration method in which the vibration generator (1) is directed upward. (1)
The device is installed in the center of the pedestal (3) which is approximately U-shaped from the front.

Ql) is a weight, and the left and right support parts (7) of the pedestal (3)
The guide shaft (4) attached and fixed to the weight 121 is supported so as to be able to rise and fall freely, and the detector (9) is mounted on the lower surface mounting part a1 of the weight 121, with its center centered on the vibration axis (5). ) is installed and arranged so that it coincides with the axis of the As in the first embodiment, there is a sound insulating body between the vibration shaft (5) and the mounting part qO.
is arranged to prevent the mounting portion 00 from being excited by acoustic energy generated from the vibration generator (1).

In addition, the sound insulation body 09 is attached to the left and right support portions of the pedestal (3) <7) (8
) consists of a sound insulating plate OQ directly bridged and fixed. Therefore, other configurations and effects are similar to those of the first embodiment.

FIG. 10 shows a third embodiment of the present invention, in which a sound insulator Q51 is attached and fixed to the mounting part (10) in the upward vibration type device [F]) as in the first embodiment. The configuration is also exactly the same.Therefore, the other configurations and effects are the same as in the second embodiment.

It goes without saying that the present invention is not limited to the embodiments described above, and is open to various design changes. For example, in the first embodiment, instead of the balance weight 0'4, there is a balance hole (A) on the side surface of the left support part (7) for balancing the left and right support parts (7) and (8). It is also preferable to form (see imaginary lines in FIG. 2). Further, the configuration and location of the sound insulation body (5) are not limited to the illustrated example as long as they have the same function. For example, as shown by the imaginary line in FIG. If (a) is extended to form a lid shape, the sound insulation effect can be further enhanced. It is also preferable that the sound insulating plate OQ is formed by laminating sound insulating materials and sound absorbing materials other than the plywood a9 and lead (a) shown in FIG. 8, or by using a single material.

Furthermore, as shown in FIG. 11, when the cross-sectional area of the test piece (11) is much smaller than the upper surface area of the seat α4), the acoustic energy generated from the vibration shaft (5)
4) to generate acceleration in the detector (9), which may cause an error in the load measurement of the detector (9).
In such a case, an auxiliary sound insulating body (c) is installed between the vibration axis (5) and the catch seat σ4) to block the propagation of the acoustic energy to the catch seat σ→, thereby preventing detection. It may also be configured to prevent acceleration of the device (9) from occurring. In addition, in the specific example of FIG. 11, the auxiliary sound insulation body (c) is a sound insulation plate QfD.
Although the vibration isolating member 0 is mounted and fixed on the top surface of the sound insulating body (15+) through the vibration isolating member 0, it is also preferable that the sound insulating body 09 is mounted and fixed at an appropriate location on the frame (3) instead of on two sides. Also, sound insulation board f) efF! It is preferable to use a flat plate like the sound insulating plate αQ of the sound insulating body a9, but if the opening diameter of the central hole (A) is made variable as in a configuration like a camera aperture device, various tests with different cross-sectional areas can be performed. It can be used as appropriate for piece 01).

The present invention has the configuration as described in detail above, and has effectively achieved its intended purpose. In particular, the vibration axis (5) of the vibration generator (1)
) and the mounting part σO of the detector (9), the sound insulator Q51 is placed between the mounting part σO of the detector (9), so that the acoustic energy generated by the vibration of the vibration shaft (5) when the vibration generator (1) is driven is absorbed by the mounting part. Therefore, the energy does not excite the mounting part QO, and the acceleration of the detector (9) is prevented, thereby ensuring highly accurate load measurement. I can do it.

Flat 10

[Brief explanation of drawings]

Fig. 1 is a plan view of the first embodiment of the present invention, Fig. 2 is a front view thereof, Figs. 3 to 6 are front views for explaining the function of the balance weight, and Fig. 7 is its front view. 8 is a sectional view of the sound insulating plate, FIG. 9 is a front view of the second embodiment, FIG. 10 is a front view of the third embodiment, and FIG.
The figure is a partially sectional front view showing the main parts of the fourth embodiment. (1)...Vibration generator, (9)...Load detector, (
]0... Mounting part, aυ... Test piece, Wire... Sound insulator. Patent applicant International Mechanical Vibration Research Institute Co., Ltd. Me Q M Unj Question 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 4 1 [B 4 ] 0 7 ------- ------

Claims (1)

[Claims] / Between the excitation axis (5) of the vibration generator (1) that excites the test piece 0υ and the mounting part αO of the load detector (9) that detects the load applied to the test piece 0]), A sound insulator α9 is provided, thereby blocking the propagation of the acoustic energy generated from the vibration generator (1) to the mounting portion (10),
A dynamic spring constant measuring device characterized in that the device is configured to prevent acceleration of the detector (9) due to the energy.