JPH01154735A - Method and apparatus for inspecting internal of steel cord - Google Patents

Abstract

PURPOSE:To inspect whether untidy endings and skip stoics present or not in steel cords by a method wherein the steel cords in steel cord-filled material are detected with magnetic sensors so as to circulate the interval between the steel cords in order to check whether said interval lies within the allowable range or not. CONSTITUTION:AC signals produced by Hall voltage, which becomes maximum every time the center of a steel cord reaches the installation position of a magnetic sensor 6. A comparator 32 issues H-level output signals as long as the waveform of the AC signals is larger then the reference voltage so as to supply them through a diode 36 to a one-shot-mltivibrator 38 in order to measure a time between the generation of one output phase and that of the next output phase or a period T and consequently to be able to calculate the interval between steel cords. The value counted with a counter 42 is supplied to a comparator 44 so as to be compared with an allowable value set at a setter 46. When said counted value lies within the range of the allowable value, neither untidy endings nor skip stiches are taken for being present, resulting in lighting an OK indicating lamp 48 for automatic checking.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention is directed to steel cord-containing materials, particularly rubber-coated tire constituent materials such as steel cord trackers and steel cord carcass plies, in which each steel cord has a predetermined shape. The present invention relates to a method and apparatus for inspecting whether or not the interval is maintained.

<Prior art> In general, steel cord breaker or carcass ply is made by covering (topping) steel cord blind fabric with rubber on both sides using a calender, cutting it to a predetermined angle and width, and then removing the non-stick parts of the cut pieces. It is manufactured by joining the cut edges together to form a strip. At this time, when the steel cord is running inside the calender device, the ends (spacing) of the steel cord may become disordered due to the disordered running path of the cord or uneven tension, or when the steel cord is topping. Cutting the steel cord may result in skipped stitches in the steel cord.

Conventionally, the above-mentioned inspection for irregularities in the ends and skipped stitches has been carried out by taking an X-ray photograph of the completed breaker or carcass ply, visually observing the photographed image, and checking whether there is irregularity in the ends or skipping. It was being done.

<Problem to be solved by the invention> However, the above inspection requires an X-ray generator, an X-ray imaging device, and an X@shielded room in which these are installed, resulting in a problem that the equipment used for the inspection becomes large. There was a point. Also, X
Since X-rays are used, the place where the test can be performed is limited to an X-ray shielded room equipped with the above-mentioned equipment, and the workers who carry out the test are also limited to those who can handle X-rays.
There was also the problem of poor workability.

<Means for Solving the Problems> In order to solve the above-mentioned problems, the present invention provides a method and apparatus for detecting steel cords using a magnetic sensor and inspecting the spacing between the steel cords. The purpose is to

Therefore, the steel cord inspection method, which is the first invention, includes the steps of sequentially detecting steel cords in a material containing steel cords using a magnetic sensor, and calculating the spacing between the steel cords based on the detection results. , the step of determining whether the calculated interval is within a predetermined tolerance, and the step of outputting the determination result.

A steel cord inspection device, which is a second invention, is a device used to carry out the first invention, and is arranged near a conveying means that conveys a material containing steel cords, and detects steel cords in the material. a magnetic sensor that generates a detection output at each interval, a means for calculating the interval between the steel cords based on the generation interval of the detection output, and a means for comparing the calculated interval with a predetermined tolerance value and comparing the result of the comparison. and a comparison means for outputting the output.

Effect〉 When a magnetic sensor approaches an object with high magnetic permeability, the generated voltage increases, so if the magnetic sensor is placed near a material containing steel cord, the steel cord will be near the magnetic sensor. As you get closer, the voltage generated increases because the steel cord is an object with high magnetic permeability. Therefore, the steel cord is detected. Steel cords are detected sequentially in this way, and the interval between steel cords can be calculated by adding up the interval from when a steel cord is detected in this way until the next steel cord is detected (114). . The distance between the steel cords calculated in this way is compared with a predetermined tolerance value to determine whether there is no irregularity in the ends, I or skipped stitches, and the results of the comparison are output. It is possible to inspect whether there is any disturbance or skipped stitches.

<Example> As shown in FIG. 2, the tire breaker or carcass ply l to be inspected according to this example consists of each steel cord 2 topped with a rubber layer 4 on both sides, cut, and then subjected to a joining process. A belt-shaped body (Fig. 2 (b)) was manufactured using the above methods. Steel cord 2 of this strip
are arranged in a direction transverse to the length direction of the strip.

In this example, a total of six types of steel cords, in which the diameter a of the steel cord 2, the touch b of the steel cord 2, and the thickness C of the rubber layer 4 are as shown in the table below, are tested. In addition,
In the table below, T and f are the period and frequency described later.

Such belt-like shear force and carcass ply 1 are conveyed by a conveyor (not shown) in the direction of the arrow (FIG. 2 (b)) at a constant speed of 30 cm/lin, for example, and wound around a winding roll. taken. In order to detect this moving steel cord 2, a plurality of magnetic sensors 6 are installed near the conveyor.
Alternatively, they are fixedly provided in parallel in the width direction of the breaker or carcass ply l with a Teflon plate 8 interposed therebetween. This magnetic sensor 6 consists of a Hall element 10 and a permanent magnet 12, as shown in FIG. When a magnetic field with magnetic flux density B is applied to the current I
Hall voltage Vj in the direction perpendicular to the direction of C and the magnetic flux density B
The magnitude of the Hall voltage V is proportional to the magnitude of the magnetic flux density B and the magnitude of the current Ic. Therefore, when the rubber layer 4 between the steel cords 2 is in the position where the Hall element 10 is installed, the magnetic field from the permanent magnet 12 is applied to the Hall element 10 only through the rubber layer 4, so the magnetic flux density B is small. , the Hall voltage V)l is also small, or the magnetic permeability of the steel cord 2 increases as it approaches the steel cord 2 or the magnetic sensor 6.
The magnetic flux density B applied to the steel cord 2 gradually increases, and the Hall voltage V□ generated by the Hall element 1O gradually increases as shown in FIG. 4(a). When the Hall element 1O is in the center or at the installation position 1, the Hall voltage V is at its maximum, and as the steel cord 2 moves away from the magnetic sensor 6, the Hall voltage 2H gradually decreases until the next steel cord 2 approaches. and,
The Hall voltage vH increases again. Therefore, the Hall voltage vH becomes an AC signal that reaches the maximum value every time the center of the steel cord 2 reaches the installation position of the magnetic sensor 6, and its period T is determined by the pitch b of the steel cord 2 and the conveyance speed of the conveyor. , the above A to F have the values shown in the above table, and the frequency f, which is the reciprocal of the period T, also has the values shown in the above table.

As shown in FIG. 1, the Hall voltage vH from the magnetic sensor 6
is amplified by differential amplifier 14 and amplifiers 16 and 18. A low-pass filter 20.22 and a bypass filter 24 are provided before and after the differential amplifier 14 and amplifiers 16.18. The cut-off frequency of the low-pass filter 20.22 is selected to be 470 Hz, and the cut-off frequency of the bypass filter 24 is selected to be zzonz. These low-pass filters 20, 22 and bypass filters 24 are for removing signal components other than the Hall voltage Vll, and as is clear from the table above, the maximum frequency of the breaker and carcass ply to be inspected is 454.511□ , the lowest frequency is 250, OH□, so even if there is a disturbance in the ends or skipped stitches in steel cord 2, the frequency of the Hall voltage V□ at that time will be within the range of the above cutoff frequency, so it will be cut off again. The frequencies have been selected to the above values. In addition, 2
6 is a variable resistor for offset adjustment, and 27 is a power supply unit for the magnetic sensor 6.

Hall voltage v) amplified by each amplifier 14.16.18
The signal l is supplied to the minus limiter 28, and has a waveform with the minus side cut off as shown in FIG. 4(b). The waveform cut in this way is supplied to a comparator 32 via a diode 30, and is supplied to a comparator 32 via a variable resistor 34 as shown in FIG.
It is compared with the reference voltage set as shown by the dotted line in b). The comparator 32 is configured to generate an H level output signal as shown in FIG. 4(c) while the cut waveform is higher than the reference voltage. This output signal is
It is supplied to a one-shot multivibrator 38 via a diode 36. Note that the diode 30.36 is
It is provided to further cut the minus side of the signal that has been minus limited by the minus limiter 28.

This one-shot multivibrator 38 responds to the rising edge of the supplied output signal and generates an H level output signal for a predetermined time (0.1 seconds) as shown in FIG. 4(d). The generation interval of the output signal of this one-shot multivibrator 38 is equal to the period T of the Hall voltage vH, and has a value proportional to the pitch of the steel cord 2. Therefore, by measuring the time from when the one-shot multivibrator 38 generates an output pulse to when it generates the next output pulse, the period T
, and thus the interval between the steel cords 2 can be calculated. Therefore, in this embodiment, the clock pulse counter 42 of 1 pulse 80 JLS generated by the clock pulse generator 40 is used to count the period from when the one-shot multivibrator 38 generates an output pulse until the next output pulse is generated. I am repeating the steps one by one. This counter 42
The count value is supplied to the comparator 44 and compared with the allowable value set in the setting device 46. This allowable value is calculated and set based on the pitch that is previously allowed as a disturbance in the steel cord 2 depending on the type of breaker or carcass ply l currently being inspected. Comparison section 44
If the count value of the counter 42 is within the range of allowable values, it is assumed that there is no irregularity or skipped stitches, and the OK indicator light 48 consisting of an LED is turned on, and if the count value of the counter 42 is outside the range of allowable values, If there is an end or skipped stitch, the OUT indicator light 50 consisting of an LED is turned on, and
Activate the buzzer 52. Therefore, if the steel cord 2 has skipped stitches or irregular ends, it is automatically checked.

In the above embodiment, the interval between the steel cords 2 is detected by measuring the time from when the negative limited Hall voltage v)I becomes equal to or higher than the reference voltage until it becomes equal to or higher than the reference voltage. Limited Hall voltage vH
The interval between the steel cords 2 may be detected by detecting the peak of , and measuring the time from this peak to the next peak. In addition, in the above embodiment, the shear force and carcass ply l
Although the magnetic sensor 6 is fixedly disposed by running the magnetic sensor 6, it is also possible to fix the shearing force and the carcass ply and move the magnetic sensor 6 at a constant speed over the breaker or the carcass ply.

<Effects> As described above, according to the present invention, a magnetic sensor is used to detect steel cords of a material containing steel cords, calculate the interval between the steel cords, and check whether this interval is within an allowable range. Depending on whether or not the steel cord has irregular ends or skipped stitches, the steel cord is inspected. Therefore, it can be made smaller than a conventional inspection device using an X-ray imaging device, etc., and can be installed anywhere without being subject to restrictions on its installation location. In addition, since X-rays are not used, safety is high, and the worker performing the inspection does not need to have any special qualifications, improving work efficiency.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of one embodiment of the present invention, Fig. 2 (a) is a diagram showing the installation state of the magnetic sensor of the same embodiment, and Fig. 2 (b) is a diagram showing the arrangement state of the strip breaker and the magnetic sensor. FIG. 3 is a perspective view showing a magnetic sensor of the same embodiment, and FIG. 4 is a diagram showing waveforms of various parts of the same embodiment. 2...Steel cord, 6...Magnetic sensor, 3
8... One-shot multivibrator, 42...
... Counter, 44... Comparison section. Patent Applicant Sumitomo Rubber Industries Co., Ltd. Agent Satoshi Shimizu

Claims (3)

[Claims] (1) a step of sequentially detecting steel cords in a material containing steel cords using a magnetic sensor; and a step of calculating an interval between the steel cords based on the detection results;
A steel cord interval inspection method comprising the steps of determining whether the calculated interval is within a predetermined tolerance, and outputting the determination result. (2) The steel cord spacing inspection method according to claim 1, wherein the material containing the steel cord is moved and the magnetic sensor is fixed. (3) A magnetic sensor that is disposed near the conveying means that conveys the steel cord-containing material and generates a detection output every time it detects the steel cord of the material, and a magnetic sensor that generates a detection output every time it detects the steel cord of the material, and A steel cord interval inspection device comprising means for calculating the interval between cords, and comparison means for comparing the calculated interval with a predetermined tolerance value and outputting the comparison result.