JPH0624723Y2 - Shape detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a shape detector for a strip-shaped thin metal plate such as a steel plate, a stainless plate, an aluminum plate and a copper plate.

(Prior Art) A number of methods have been put into practical use for online shape detection of thin metal strips. For example, the roll shell part is divided into links and the shell part is installed in the inner cylinder. There is known a split roll type shape detector or the like in which a load cell is supported, a large number of these shells are combined to form one roll, and the shape of the plate is known from the output of the load cell.

However, the shape detector of the split roll type has drawbacks such as scratches on the plate and bending of the waist due to contact with the split joint surface.

(Problems to be Solved by the Invention) An object of the present invention is to solve the above-mentioned problems and to provide a shape detector extremely advantageous for detecting the shape of a thin metal strip.

(Means for Solving Problems) In order to advantageously solve the problems of the split roll system described above, in a shape detector in which a diaphragm is provided on the roll surface and the strain of the diaphragm is detected by a strain gauge, the diaphragm is a roll. The pair of diaphragms are arranged at equal distances from the center of the length direction along the length direction of the roll, and the pair of diaphragms are arranged with the angle shifted by 180 degrees in the rotation direction of the roll. The shape detector is provided individually.

Further, in the shape detector of the present invention, the strain gauge output of the pair of diaphragms is a shape detector connected to the same side of the Wheatstone bridge or to the opposite side. According to the present invention, the outputs from many diaphragms are collected. It becomes possible to detect it, and the number of amplifiers and the number of strands decrease,
Moreover, the S / N ratio can be improved.

Next, the shape detector of the present invention will be described in detail with reference to FIG.

A plurality of diaphragms 2 are spirally arranged in the circumferential direction of the roll 1, and a strain gauge such as a semiconductor strain gauge 3 is attached to the diaphragm 2. As for the installation position of the diaphragm 2, for example, a'is arranged at a position equidistant from the center of the roll width direction with respect to a and a position shifted by 180 ° in the rotational direction. Similarly, b ′ with respect to b and c ′ with respect to C have the same point symmetry. By thus shifting the phase of the position of the diaphragm according to the rotation direction, the contact between the plate 5 and the diaphragm 2 is a ′ → b ′ → due to the rotation of the roll.
It moves with c ', but one point is that it is always in contact,
Therefore, it becomes possible to incorporate all signals of the diaphragm 2 into one connection.

An example of the wiring method is shown in FIG. (a) and (b) are diaphragms
This is an example of Wheatstone bridge in which 12 pieces are connected in the same way, and (c) is an example of 16 diaphragms. The feature here is that the paired diaphragms, for example, a'for a and b'for b are always located on the same side or opposite sides of the bridge.

FIG. 3 shows how to arrange the diaphragm.
A spiral shape as shown in (a) and a plurality of spiral arrangements as shown in (b) can be adopted.

The operation of the present invention will be described.

As shown in the section A-A in FIG. 1, when the plate 5 of the material to be measured is threaded on the upper part of the roll 1, the strains or stresses of the diaphragms a and a ′, or the change of the electric resistance value,
Alternatively, the output from the dynamic strain gauge 6 is as shown in the left diagram of FIG.

It should be noted that in the following text, the strain of the diaphragm, the stress, the change in the electric resistance value, or the output from the dynamic strain gauge 6 will be summarized and described as strain.

In this case, the vertical axis of FIG. 4 is the distortion, and the horizontal axis is the time axis.

That is, in the diaphragm, the strain due to the contact between the diaphragm and the plate, which is necessary to obtain the shape of the plate, and the roll are
The bending strain generated by the weight of itself and the acting force from the plate is combined and generated. Here, since the strain due to bending becomes an obstacle in measuring the shape, the canceling method is important. The cancellation method will be described in detail below.

In the cross-sectional view taken along the line AA of FIG. 1, the time-series change amount of the strain of the diaphragm a ′ is explained starting from the time when the diaphragm a ′ reaches the left horizontal point, and FIG. In the lower left. When the diaphragm a'rotates in the direction of the arrow, the diaphragm a'is (-), due to the bending of the roll.
Or the compression distortion occurs, and it becomes the maximum when it rotates 90 degrees and reaches the apex. When the rotation further advances, it decreases, and when it rotates 180 degrees, (+) or tensile strain occurs.

On the other hand, when rotated by 90 degrees, the diaphragm a ′ comes into contact with the plate and the diaphragm is pressed by the plate, so that the diaphragm a ′ is slightly elastically deformed into a concave shape, so that the strain gauge mounted inside the diaphragm a ′ Causes steep (+) or tensile strain.

The upper left of FIG. 4 describes the strain of the diaphragm a, and the mechanism of strain generation is similar to that of the diaphragm a ′.

Here, since the diaphragm a is offset by 180 degrees in the rotational direction with respect to the diaphragm a ′ and is provided as a pair equidistant from the center of the roll length direction, the amount of strain generated is equal and the phase is 180 °. It is a change in the amount of distortion with a deviation.

From the above, by adding the strain of the diaphragm a ′ and the strain of the diaphragm a, the strain due to bending can be canceled as shown in the right side of FIG.

In the measurement using the strain gauge and Wheatstone bridge,
An outline of a method for canceling bending strain will be described.

The resistance change amount r of the strain gauge due to the strain is determined by r = RKε, where ε is the strain amount, R is the initial resistance value of the strain gauge, and K is the gauge factor of the strain gauge.

Therefore, the amount of resistance change due to bending strain of the diaphragm a ′ is r _{a ′} = RKε _{a ′} ε _{a ′} : Bending strain On the other hand, the amount of resistance change due to bending strain of the diaphragm a is r
_a = RKε _a ε _a : Bending strain Here, the strains of the diaphragms a ′ and a have the same level,
Since the phases are 180 degrees out of phase, the amount of resistance change is the same,
When the resistance of the diaphragm a ′ is reduced by ra _′ [Ω], the resistance of the diaphragm a is increased by r _a [Ω] and | −r _{a ′} | = | + r _a | Is a value shifted by 180 degrees.

In the strain measurement, the absolute value is equal, the method of configuring the Wheatstone bridge that cancels the positive and negative resistance change amount,
The methods of (a), (b) and (c) in FIG. 2 are used.

FIG. 2 (b) shows a system in which a pair of diaphragms a ′ and a are incorporated on the same side. In this case, the resistance change amount Σr = (− r _{a ′} ) + (+ r _a ) = 0 due to bending strain. , The distortion due to bending can be canceled.

FIG. 2 (a) shows a system in which a pair of diaphragms a'and a are incorporated in the opposite side. In this case as well, the unbalance amount of the Wheatstone bridge is the difference between the product of the opposite side and the product of the other opposite side. The product of the resistance values when strain is applied by bending the opposite side incorporating the diaphragm is: ΣR = {3R + (− r _{a ′} )} {3R + (+ r _a )} where | −r _{a ′} | = | + r _a | ΣR = (3R) ² − (r) ² Therefore, the difference from before the strain application is (r) ² [Ω].

Bending strain is 500 × 10 ^-6 , strain gauge initial resistance value is 120
[Ω], assuming a gauge factor of 2, and calculating r, r =
0.12 [Ω], (r) ² = 0.014 [Ω], and (3R) ²
On the other hand, it is 1.08 × 10 _-5 %, which is an error range that can be neglected in measurement, which is the same as the cancellation.

The same can be proved for (c) of FIG. 2, but it is omitted.

FIG. 5 shows an example of the circuit up to the shape display.

That is, the signal of the diaphragm 2 is configured as one bridge and is connected to the dynamic strain gauge 6 via the slip ring 4.
A rotary transformer may be used instead of the slip ring 4.

On the other hand, in a shape detector used in high-speed rotation, the phenomenon of the output waveform of the diaphragm itself is fast, so the signal from the sensor 7 that detects the position of the diaphragm is used to trigger the trigger and perform processing such as peak hold 9.

As described above, the function of reading the output signal using the signal from the diaphragm 2 and the signal from the position detection sensor 7, identifying the position of the diaphragm, and further calculating the tension and shape of the plate from the output signal of the diaphragm The shape is displayed on the display device 11 such as a CRT through the position discriminator 10 by using a microcomputer or the like for reading.

FIG. 6 shows an example of the display, which is triggered by the diaphragm position signal, reads the diaphragm output, and displays the shape distribution on the CRT with the horizontal axis as the plate width.

(Effect of the Invention) With the shape detector according to the above method, a very compact and highly accurate shape detector is realized, and the effect is extremely large.

[Brief description of drawings]

FIG. 1 is an explanatory view of a shape detector according to the present invention, FIG. 2 is an explanatory view showing an example of connection of a Wheatstone bridge of the present invention, FIG. 3 is an explanatory view showing a diaphragm arranging method, and FIG. 4 is FIG. 5 is an explanatory view showing the principle of the present invention, FIG. 5 is a circuit diagram of shape detection according to the present invention, and FIG. 6 is an explanatory view showing waveforms and display results by the shape detector of the present invention. 1 ... Roll, 2 ... Diaphragm, 3 ... Semiconductor strain gauge, 4 ... Slip ring, 5 ... Plate, 6 ... Dynamic strain gauge, 7 ... Position detection sensor, 8 ... Amplifier, 9 ...... Peak hold device, 10 ...... Read position discriminator, 11 ……
Display meter.

Claims (1)

[Scope of utility model registration request] 1. A shape detector in which a diaphragm is provided on a roll surface and strain of the diaphragm is detected by a strain gauge,
Diaphragms are arranged in pairs at equal distances from the center of the roll length direction along the roll length direction, and the pair of diaphragms are arranged with an angle offset of 180 degrees in the rotation direction of the roll. A shape detector that is equipped with multiple diaphragms.