JPS5945082B2 - Clearance measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a gap measuring device for measuring the gap between conductive materials arranged side by side and facing each other.

In structures constructed by joining sheet metal materials with bolts, or structures assembled by numerous columns, the dimensions of the gaps at the joints and the spacing between the columns, so-called gaps, often affect the function of the structure. be.

However, if the gap is soaked with liquid such as water,
There were many cases where the gaps were located inside the structure and could not be measured using calipers or gap gauges.

The present invention eliminates the above-mentioned drawbacks, and consists of an electrode plate consisting of a shielding plate with a low dielectric constant and a pair of electrodes having a predetermined area attached to both sides of the plate, which face each other with a gap between them. The capacitance between one of the electrodes and the conductor object and the capacitance between the other electrode and the conductor object are measured by inserting it between the conductive materials arranged in parallel. It is characterized by the fact that z is used to measure the distance, and its purpose is to provide a gap measuring device that accurately measures the size of the gap between conductive objects arranged side by side facing each other.

As described above, the present invention involves inserting an electrode plate, which is made by pasting a pair of electrodes having a predetermined area on both sides of a shielding plate with a low dielectric constant, into conductive materials arranged in parallel facing each other. Since it measures the capacitance between the electrodes and the above-mentioned pair of electrodes, it is a gap measuring device that is useful when there are gaps in the water that could not be measured with conventional calipers or gap gauges.

Hereinafter, one embodiment of the present invention shown in FIGS. 1 and 2 will be described.

Reference numeral 1 denotes a film-like shielding plate made of, for example, vinylidene chloride having a low dielectric constant, and a pair of electrodes 2a and 2b having a predetermined area are adhered to both sides of the shielding plate 1 to constitute an electrode plate T.

3a to 3c are lead wires, one end of which is connected to a measuring device for measuring capacitance (not shown), while the other ends of lead wires 3a and 3b are connected to electrodes 2a and 2b, respectively, and lead wire 3c. are conductor materials A arranged in parallel facing each other.
(It is connected to 5B.

Here, the capacitance of the distance D between the electrode 2a and the conductive material A is Ca electrode 2b
and the capacitance of the distance D2 between the conductive material B and the Cb electrode 2a and the electrode 2
Capacitance C, measured between lead wires 3a and 3c; capacitance C, measured between lead wires 3b and 3c; ) The equivalent circuit of FIG. 1 is as shown in FIG. 2.

Now, the space between the conductor materials A and B is filled with a liquid having a dielectric constant of ε, and the electrode plate T is inserted into the gap, and the lead wire 3
Suppose that c is connected to the conductive materials A and B above.

Area A of electrodes 2a and 2b, relative dielectric constant ε2 of shielding plate 1
, dielectric constant ε in vacuum.

Then, Ca=εo・ε,・A/D,,・・・・・・(
1) Cb=εo・εpiA/D2,...(2)C
It is expressed as c=εo·ε2·A/D, (3).

Also, since C1=Ca+1/(1/Cb+1/Cc), substitute equations (1), (2), and (3) into C1=εo・εpiA/d1+εo・ε1・A/(D2+ε1・D3/ε2
).

......(4) is obtained. Here, since ε1/ε2 is sufficiently large, the second term on the right side of equation (4) is almost constant regardless of D2.

Therefore, by setting the same second term as CO, D,=εo·εbiaA/(C1−CO).

Similarly, C2=Cb+1/(1/Ca+1/Cc)=εo
・ε1・A/D2+G.゜． d2=j・εpiV(C2-C?.) That is, the distance Dl, d2 between the electrode plate T and the conductive materials A and B is determined by the capacitance measured from the lead wires 3a, 3c and 3b, and 3c. Therefore, by adding the thickness of the electrode plate T itself, the dimension of the gap between the conductor material A and B can be measured.

As described above, in this embodiment, a pair of electrodes 2a and 2b having an area A are attached to both sides of a shielding plate 1 having a low dielectric constant to form an electrode plate T8lm, and a conductor material A-
The electrode plate T is inserted between B, and the lead wire 3c is connected to the conductive material A-B, and the wire 3c and the electrode 2a are connected to each other.
・By measuring the capacitance between the lead wires 3a and 3b connected to 2c, the conductor material A-B
Since it is possible to measure the dimensions of the gap between gaps, it is possible to measure relative gaps that cannot be measured with conventional calipers or gap gauges, such as when the gap to be measured is inside a structure or the same area is immersed in liquid. It is possible to measure the gap between conductive materials placed side by side.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing one embodiment of the present invention, and FIG.
FIG. 2 is an equivalent circuit diagram of FIG. 1: Shielding plate, 2a and 2b: Electric IfL3a to 3c
: lead wire, A and B: conductor material, T: electrode plate.

Claims (1)

[Claims] 1. An electrode plate consisting of a shielded wave with a low dielectric constant and a pair of electrodes having a predetermined area affixed to both sides of the plate is placed between conductive materials that are placed side by side facing each other with a gap between them. and measures the capacitance between one of the electrodes and the conductive material and the capacitance between the other electrode and the conductive material, thereby measuring the distance between the conductive materials. Clearance measuring device.