JP2013185916A5 - - Google Patents

Description

Tension measuring device

The present invention, by measuring the hydraulic pressure of the strain can be closed container, a device for measuring the tension force applied to the outer peripheral portion of the closed container.

Conventionally, a workpiece on the side subjected to a tension force is set on a measuring machine, and strain force due to the tension force is used to measure the tension force using a strain gauge, a piezoelectric element or hydraulic pressure.

Conventional strained gauge, for example, as shown in FIG. 1, and the inside of the upper and lower pair of flexure element 11, 11 strain is an electrical resistance detection means gauges G1, G2, G3, G4 are attached, FIG. As shown in FIG. 2, a Wheatstone bridge is formed.

When the center of a pair of the upper and lower strain body 11, 11 a compressive force is exerted from the upper and lower gauges G1, G2, G3, G4 strain compression and elongation occur, the electrical signals of the strain amount of its Wheatstone bridge As you take out.

In such a configuration, the tension force in the outer circumferential portion of the strain body 11, 11 is applied, the gauge G1, G2, G3, force component perpendicular to G4 acts on the strain body 11, 11, pushed from above and below The beam is distorted by the force. The tension force was measured by an electrical signal corresponding to the amount of strain .

However, to represent a straining force applied to the entire outer peripheral portion only vertical force, there is a real difference occurs problems with straining force, also, the rigidity of the flexure element 11, 11 have a low As a result, there is a problem that a difference from the actual tension force occurs for a large tension force. Therefore, enclosing a liquid into the strain generating possible cylindrical container, it is also conducted to measure the pressure of the liquid due to the strain generating by straining force applied to the outer peripheral portion. However, volumetric thermal expansion coefficient of the liquid is much greater than metal volumetric thermal expansion coefficient of the container serving as a strain generating body 11, 11, the pressure of the liquid varies largely even a slight temperature change, the tension force applied to the outer peripheral portion It was impossible to measure accurately.

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In order to solve the above problems, the present invention is, by matching the volumetric thermal expansion coefficient of the inner container containing encapsulated liquid, the body volume thermal expansion coefficient of the container is a strain generating section, a pressure change due to temperature It is to make it smaller.

Large liquid encapsulated volumetric thermal expansion coefficient in the container, if mixed small objects of volumetric thermal expansion coefficient, it is possible to adjust the average volumetric thermal expansion coefficient of it.

Hereinafter, an embodiment of the present invention will be described with reference to FIG. 3 of the accompanying drawings . A container 1 that also serves as a strain generating portion contains a liquid 2 and an average volume thermal expansion coefficient adjusting component 3 that is an object having a smaller volume thermal expansion coefficient than the liquid 2 , and a pressure gauge 6 is connected via a packing 4-1. Attached , the container 1 has a sealed structure. Reference numeral 5 denotes a plug, which liquid-tightly closes the liquid supply / discharge port 8 provided in the pressure gauge 6 via a packing 4-2.

Here, when receiving the radial load on the outer peripheral portion of the container 1 serving also as a strain generating section, the vessel 1 is strain generating container 1 the pressure pushes the diaphragm 7 of the pressure gauge 6, the strain-generating as an increase in pressure The amount, that is , the tension applied to the outer peripheral portion can be measured.

In this embodiment, in order to solve the above problem, the volumetric thermal expansion coefficient inside the container 1 containing the encapsulated liquid 2 can be changed by adding the average volumetric thermal expansion coefficient adjusting component 3 to the liquid 2. to match the volumetric thermal expansion coefficient of a certain container 1 metal, to reduce the pressure change due to temperature.

For example, in the above structure, using a body volume thermal expansion coefficient 33 ppm / ° C. in stainless steel vessel 1 which also serves as a strain generating part, using glycerol in the body volume thermal expansion coefficient 500 ppm / ° C. in the liquid 2, the average volumetric thermal expansion when using Invar rate adjustment component 3 to the body volume thermal expansion coefficient 6 ppm / ° C., glycerin and the volume ratio of Invar for matching the container 1 inside the volumetric thermal expansion coefficient volumetric thermal expansion coefficient of the stainless steel container 1, If the volume ratio of Invar is x and the volume ratio of glycerin is y, it can be obtained by the following calculation formula.
33 = 6x + 500y
x + y = 1
From the above
x = 467/494 = 0.9453 ... ≈0.945
y ≒ 0.055
Therefore, the volume ratio of the average is a volumetric thermal expansion coefficient adjusting part 3 Invar is about 0.945, the volume ratio of glycerol is liquid 2 is about 0.05 5.
In the liquid 2 to be enclosed in the container 1, explosion technique contamination of the gas subjected to vacuum defoaming and heating degassing, it is possible to eliminate the influence of gas. Further, with respect to adjustment of the by that volumetric thermal expansion coefficient for mixing with the liquid 2 and the average volumetric thermal expansion coefficient adjusting member 3, by adjusting the thickness of the packing 4-1, adjusting the amount of liquid 2 it is also possible.

Is an explanatory diagram of the slave come example. Is an explanatory view of the internal connection of the slave come example. It is a fragmentary sectional view showing the example of the present invention.

1 container 2 liquid 3 average volume coefficient of thermal expansion adjustment part 4 packing 5 plug 6 pressure gauge
7 diaphragm
8 liquid inlet / outlet
11 strain body
G1-G4 strain gauge

Claims (1)

The liquid pressure in the strain generating possible closed container in straining force applied to the outer peripheral portion is measured, an apparatus for measuring the tension force, the tight closed container in a liquid body in the volumetric thermal expansion coefficient the by than the liquid put small objects, straining force measuring device characterized by matching the average volumetric thermal expansion coefficient of the inside of the sealed container to the volumetric thermal expansion coefficient of the container.

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