JP2010236999A - Device for measurement of circularity in bar steel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a circularity measuring device for measuring circularity of a bar steel under online conveyance highly accurately over the whole length of the bar steel. <P>SOLUTION: Three light projection/reception type outer diameter meters 1 are arranged so that each edge of the bar steel can be detected by each meter, on a residual surface acquired by excluding a bar steel passing part from one plane perpendicular to a conveyance direction 15 of the bar steel 2, to thereby form one set of a sensor unit 5. At least four sets of the sensor units are arranged in series in the bar steel conveyance direction on each different edge detectable position between each different set. A diameter of a circle passing three points of each edge position detected by each sensor unit is determined, and three-point micro-method operation for deriving circularity based on a difference between the maximum value and the minimum value thereof can be executed over the whole length of the bar steel. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a roundness measuring apparatus for a steel bar, and more particularly to a roundness measuring apparatus for a steel bar that measures the roundness of a steel bar with high accuracy of about 10 μm over the entire length.

  As a conventional technique as a background, there is a method for measuring a profile of a three-roll rolled material described in Patent Document 1. This is because, as shown in FIG. 5, at least six outer diameter meters 1 by a projection beam method in which a pair of a projector 1a and a receiver 1b sandwich a rolled material (steel) 2 on the exit side of a three-roll rolling mill (projector) 6 pairs of 1a and light receivers 1b), fixedly arranged at equal intervals in the circumferential direction around the axis of the rolled material in the same plane parallel to the cross section of the rolled material 2, and the position of the fixed arrangement is 3 A position within 100 times the diameter of the rolled material from the center of the roll mill is suitable.

Japanese Patent No. 3845255

In the measuring apparatus according to the background art, in order to measure the profile of the bar more accurately, it is necessary to simultaneously detect a large number of edge positions on the outer circumference of the bar, that is, <1><2> below.
<1> A large number of outer diameter meters (approximately 10 to 20 or more in the case of edge detection on one side) are fixedly arranged on the same cross section.
<2> Measure them at the same timing (measured in synchronization).

  On the other hand, as shown in FIG. 6, in the light emitting / receiving outer diameter meter, the distance between the light projector 1a and the light receiver 1b (the distance between the light projector and the light receiver) depends on the measurement accuracy and the measurement range, but is about 30 mm. In general, the upper limit is the distance from the light receiver 1b to the target point P occupying the edge position of the steel bar 2 for high-precision measurement of the order of several hundred millimeters. There is a distance constraint as it is said that it is necessary to provide.

  Therefore, if a large number of outer diameter meters having a short interval between the light emitter and the receiver are arranged on the same cross section, as shown in FIG. 7, interference 20 between adjacent outer diameter meters 1 occurs. > Is not feasible. Also, in order to synchronize a large number of outer diameter meters, special specifications and design are indispensable, and the above-mentioned <2> is realistic because there is a huge cost increase and the number of units that can be synchronized is limited. That's not true.

  As described above, the conventional technique has an unsolved problem that online high-precision measurement of the roundness of a steel bar using a light emitting / receiving type outer diameter meter is impossible.

In order to solve the above-mentioned problems, the present invention has focused on applying a three-point micro method known as a method for measuring the roundness of a steel bar stationary offline to the measurement of the roundness of a steel bar during online conveyance.
When measuring the outer diameter of a stationary steel bar by the three-point micro method, as shown in FIG. 1 (a), the three contact surfaces 31, 32, 33 of the three-point micrometer 30 (the contact surface 31 of the three surfaces). , 32 is fixed, and the contact surface 33 is movable), and the outer diameter value is obtained from the scale of the measuring rod 34 having the movable contact surface 33 as the tip surface.

  Since the three abutment surfaces are arranged so as to circumscribe the trisection point of the same circumference (at an angle between the adjacent surfaces of 60 °), as shown in FIG. The tangent line between the circumferential circle O (meaning a circle centered on the circle O) and the contact surfaces 31, 32, 33 forms an equilateral triangle (ΔABC), the diameter D of the circle O and the height h of ΔABC, Has a relationship of h = (3/2) × D. Therefore, in the 3-point micro method, the scale system of the measuring rod 34 is a scale system in which the point A is zero and the scale unit width is 3/2 times that of the 2-point micro method. As in the case, the diameter D can be read directly from the scale.

The three-point micro method is more reliable in roundness measurement than the two-point micro method. The reason will be described with reference to FIG.
As shown in FIG. 2, the roundness of the steel bar is represented by the difference between the maximum diameter and the minimum diameter of the cross section of the steel bar. As the maximum diameter is closer to the diameter of the circumscribed circle (true maximum diameter) of the cross section of the steel bar, and the minimum diameter is closer to the diameter of the inscribed circle (true minimum diameter) of the cross section of the steel bar, the measurement reliability is high. In this regard, the three-point micro method is compared with the two-point micro method. In the three-point micro method, as shown in FIG. The circle 40 is determined by the three-point contact, and the circle 40 is very close to the circumscribed circle when the maximum diameter is detected, and is very close to the inscribed circle when the minimum diameter is detected. On the other hand, in the two-point micro method, as shown in FIG. 2 (b), one cross-sectional figure of the steel bar 2 (figure congruent with that of FIG. 2 (a)) and two parallel contact surfaces 31, 33 The circle 41 is determined by the two-point contact, and this circle 41 is smaller when the major axis (considered as the maximum diameter) is detected than when the maximum diameter of the circle 40 determined by the three-point micro method is detected. In general, the detection time is larger than the detection of the minimum diameter of the circle 40 determined by the three-point micro method. In other words, compared to the two-point micro method, the three-point micro method is closer to the true maximum diameter and the detected minimum diameter is closer to the true minimum diameter. It can be said that the nature is higher.

Note that the definition of roundness is not limited to the formula shown in FIG. 2: roundness = maximum diameter-minimum diameter, roundness = (maximum diameter-minimum diameter) / nominal diameter x 100 (%) , Roundness = (1− (maximum diameter−minimum diameter) / nominal diameter) × 100 (%), etc.
The present inventors examined the roundness measurement of the steel bar by a three-point micro method using a light emitting / receiving type outer diameter meter, and obtained the following knowledge.
1) With the remaining surface excluding the steel bar threading portion from one plane perpendicular to the steel bar threading direction as the placement surface, three outer diameter meters can be detected in the placement surface, and each stand can detect the edge of the steel bar. Need to be arranged.
2) It is necessary that the arrangement surface has at least four sets along the steel bar threading direction in which the position where the edge can be detected by the outer diameter meter varies depending on the arrangement surface.
3) The three outer diameter meters in the same arrangement plane are preferably arranged at 120 ° intervals in the circumferential direction, but roundness measurement is possible even in other cases.
4) The outer diameter meter is preferably one that detects one edge of a steel bar, but may be one that detects both edges.
5) Find the diameter of the circle that passes through the three points of the edge position detected by the three outer diameter meters in the same arrangement plane for each of at least four different arrangement planes, and maximize the maximum value among them. The roundness can be derived from the difference between the maximum diameter and the minimum diameter, with the diameter and the minimum value as the minimum diameter.
6) The roundness of 5) can be derived over the entire length of the steel bar.

This invention is made | formed based on the said knowledge, The summary is as follows.
(Claim 1) Three light emitting / receiving type outer diameter meters are arranged in the remaining plane excluding the bar passing part from one plane orthogonal to the bar conveying direction so that the edge of the bar can be detected by each unit. The sensor unit is a set, and at least four of the sensor units are arranged in series in the steel bar conveyance direction with different edge detectable positions between the different sets, and three edge positions detected for each sensor unit. The true value of a steel bar is characterized by the fact that a three-point micro method of calculating the diameter of a circle passing through the bar and deriving the roundness based on the difference between the maximum value and the minimum value can be executed over the entire length of the steel bar. Circularity measuring device.
(Claim 2) The apparatus for measuring roundness of a steel bar according to claim 1, wherein the three outer diameter meters in the same sensor unit are arranged at angular positions every 120 ° in the circumferential direction. .
(Claim 3) The roundness measuring apparatus for a steel bar according to claim 1 or 2, wherein the edge detection of the steel bar is one-side edge detection of the steel bar.

The present invention has the following effects.
(1) Even if the distance between the light emitter and the light receiver of the outer diameter meter is narrowed, it can be arranged on the same plane without interference if there are three.
(2) In the three-point micro method, the diameter can be calculated if there are at least three edge positions in the circumferential direction of the steel bar detected at the same timing, so the minimum required three outer diameter meters are not synchronized. However, it can be measured within the minimum error.
(3) Even when synchronizing, it is possible to reduce the cost of remodeling special specifications as long as three units are synchronized.

  For these reasons, according to the present invention, the roundness of the steel bar being conveyed online can be measured with high accuracy over the entire length of the steel bar.

Explanatory diagram showing the concept of the three-point micro method Explanatory drawing which shows the difference between the three-point micro method (a) and the two-point micro method (b) Schematic showing an example of an embodiment of the present invention Explanatory diagram showing the principle of 3-point micro method calculation Schematic showing an embodiment of the prior art Explanatory drawing showing the distance constraints of the light emitting / receiving outer diameter meter Explanatory drawing showing the problems of the prior art

  FIG. 3 is a schematic diagram showing an example of an embodiment of the present invention. One set of sensor units 5 is a light emitting / receiving type consisting of a light projector 1a and a light receiver 1b in a remaining plane excluding a bar threading portion from one plane perpendicular to the conveying direction 15 of the steel bar 2 on the conveying line 12. The three outer diameter meters 1 are arranged so that the edge of the steel bar 2 can be detected by each unit. The four sensor units 5 are adjusted (the arrangement positions are set) so that the three outer diameter meters 1 in each group have different circumferential edge detection detectable positions. Are arranged in series in the transport direction 15. Here, if the number of sensor unit arrangement groups is 3 or less, the number of edge detection points is 9 or less (the number of detected diameter data is 3 or less) and the roundness measurement with high accuracy cannot be expected. At least four sensor units are arranged. In the illustrated example, the number of sensor unit arrangement groups is four, but may be five or more.

  The position information of the edge position detected by the light receiver 1 b of each outer diameter meter 1 is sent to the personal computer 9 via the corresponding outer diameter meter controller 7 provided in the control panel 6. The personal computer 8 calculates the diameter of a circle (circle determined by the three-point micro method) passing through three points corresponding to the edge position detected for each sensor unit from the sent position information, and from the calculated data, The maximum value and the minimum value in all the sensor units are obtained, and a three-point micro method calculation for deriving the roundness based on the difference between the two is performed. Reference numeral 8 denotes a monitor capable of displaying calculation results and other information.

Since the three-point micro method calculation can be performed at an appropriate data sampling period over the entire length of the steel bar, the roundness can be measured over the entire length of the steel bar.
As shown in FIG. 4A, the center O of the circle 40 passing through the three points ABC corresponding to the three edge positions detected by the three outer diameter meters in the same sensor unit is represented by each side AB of ΔABC. , BC, CA is determined as the only intersection of the perpendicular bisectors, the length of the segment OC (same for OA, OB) is the radius R of the circle 40, and the diameter D = 2R of the circle 40 can be calculated. . By the way, if the three outer diameter meters 1 in the same sensor unit (specifically, positions where edges can be detected by the outer diameter meter 1) are arranged at angular positions every 120 ° in the circumferential direction, FIG. As shown in b), ΔABC is an equilateral triangle, and the diameter D of the circle 40 is calculated by using a very simple relational expression with the length L of one side of the equilateral triangle, D = 2L / √3. (In the case of an arrangement form other than the angular position every 120 °, it is necessary to use a more complicated function expression having all three position coordinates as variables). Therefore, the three outer diameter meters in the same sensor unit are preferably arranged at angular positions every 120 ° in the circumferential direction.

  Further, in the example of FIG. 3, the steel bar edge detection is the one-side edge detection, but the present invention is not limited to this, and for example, both-side edge detection as shown in FIG. However, in both-side edge detection, it is necessary to make the beam width of the light used for detection larger than the diameter of the steel bar. Therefore, the size of the outer diameter meter is larger than that in the case of one-side edge detection, and the three outer diameter meters In the present invention, it is preferable that the edge detection of the steel bar is the one-side edge detection because the problem of interference and the problem of accuracy reduction due to the distance restriction may occur again.

  From the viewpoint of facilitating maintenance of the apparatus, as shown in FIG. 3, the sensor unit 5 fixes all of the plurality of sets to one gantry, and each gantry, inside and outside the transport line 12. It is preferable that the reciprocating movement 13 between a predetermined position (online position and offline position) is possible.

In the embodiment, in the roundness measuring apparatus shown in FIG. 3, the outer diameter meters 1 are all of the one-side edge detection type, and each of the sensor units 5 has three sets of four sets, each in a circumferential direction of 120 °. All 12 units are arranged at an angular position that is every 30 ° (that is, the edge detectable position becomes each point of the circumference twelve equally-divided points), and the definition of roundness is roundness = maximum diameter -A roundness measuring apparatus having a minimum diameter. A roundness measurement method using this will be described.
(Procedure 1) Preparation before measurement;
The sensor units 5 (4 sets in total) are moved from the offline position to the online position. The computer 9 receives information such as the passing size (nominal diameter and length) of the steel bar 2 and the pass / fail judgment criteria for the roundness sent from the host computer, etc., and the height of the sensor unit 5 is received. Set (adjust) the height to match the material size.
(Procedure 2) Measurement during threading;
The steel bar 2 is transported, and the edge position is detected (sampled) at a fixed length (a constant time if it is considered that the transport speed is constant) from the tip of the steel bar 2 that is “recognized by the outer diameter meter 1” (material arrival is detected). The diameter D of the circle determined by the three-point micro method for each sampling is calculated by the personal computer 9 (see FIG. 4B), and the roundness (= maximum diameter−minimum diameter) is calculated from the total four diameter data obtained. To derive. This derivation is performed over the entire length of the bar.
(Procedure 3) Pass / fail judgment of roundness of steel bars;
If the roundness of the entire length of the steel bar obtained in the procedure 2 exceeds the pass / fail criterion, it is determined as a rejected product, and the determination result of the rejected product is sent from the personal computer 9 to the host computer or the like. The rejected product is paid out to the reject zone.
(Procedure 4) The measurement and determination in the procedures 2 and 3 are repeated.

1 Outer diameter meter
1a Floodlight
1b Receiver 2 Bar steel (rolled material)
5 Sensor unit 6 Control panel 7 Outside diameter controller 8 Monitor 9 PC
10 Roll of 3 roll mill
11 Roll axis of 3 roll mill
12 Transport line
13 Reciprocating movement
15 Transport direction
20 Interference
30 3-point micrometer
31,32 Contact surface (fixed)
33 Contact surface (movable)
40 Circle determined by the three-point micro method
41 Circle determined by the two-point micro method

Claims (3)

  Three light emitting / receiving type outer diameter meters are arranged on the remaining plane excluding the bar threading part from one plane perpendicular to the bar conveying direction so that the edge of the bar can be detected by each unit and a set of sensor units None, at least four pairs of sensor units are arranged in series in the steel bar conveying direction with different edge detectable positions between different pairs, and the diameter of a circle passing through three edge positions detected for each sensor unit A roundness measuring apparatus for steel bars, characterized in that a three-point micro method calculation for deriving roundness based on the difference between the maximum value and the minimum value can be performed over the entire length of the steel bar.   The roundness measuring apparatus for steel bars according to claim 1, wherein the three outer diameter meters in the same sensor unit are arranged at angular positions every 120 ° in the circumferential direction.   The roundness measuring apparatus for a steel bar according to claim 1, wherein the edge detection of the steel bar is one-side edge detection of the steel bar.

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