Bending Roll

Abstract

To accurately measure inner and outer diameters or a radius of curvature of a molding on a bending roll.SOLUTION: An inner diameter (2×r) of a molding W can be accurately measured by measuring a thickness t of the molding W, driving lower rolls 2 to rotate while holding the molding W between an upper roll 1 and the respective lower rolls 2 and controlling a vertical position of the upper roll 1 so that a load of pressing the molding W by the upper roll 1 is kept constant, measuring a length L1 along the circumferential direction between two first reference points A, A' on a concave circular arc surface in a circumferential portion of the molding W and a length L2 along the circumferential direction between two second reference points B, B' on a convex circular arc surface that lie opposite the respective ones of the respective first reference points A, A' in the plate thickness direction, and calculating t×L1 / (L2-L1) from the results of measurements as a measured value r of a radius of curvature of a concave curved surface of the molding W.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a bending roll that bends a metal sheet by reciprocating the metal sheet between an upper roll and a pair of lower rolls. [Background technology]

[0002] A bending roll is a device that has an upper roll and a pair of lower rolls parallel to it, and bends a metal plate by clamping the metal plate between the upper roll and each lower roll and rotating the lower rolls, thereby moving the metal plate back and forth.

[0003] Conventionally, large cylindrical molded products (e.g., welded pipes, etc.) or R-shaped molded products formed by the bending rolls as described above are removed from the bending rolls after forming is completed, and workers check the inner and outer diameters or the radius of curvature. For example, for cylindrical molded products, the outer diameter is calculated by measuring the outer periphery length with a tape measure. In addition, the method of measuring the radius of curvature by contacting an R gauge with the inner or outer surface of the molded product can be applied to both cylindrical molded products and R-shaped molded products. In addition, in the method using this R gauge, if the molded product would bend under its own weight when placed sideways, the measurement work was performed by standing the molded product upright.

[0004] However, in the method of measuring the outer periphery of a cylindrical molding with a tape measure, the measurement result may be close to the target outer diameter even if the radius of curvature of the molding varies depending on the circumferential position, making it impossible to evaluate the roundness.In addition, when the molding has a large diameter, the measurement error is large and the measurement work takes a lot of time.

[0005] Furthermore, the method of using an R gauge to measure a cylindrical molding by standing it upright has the drawback that when the molding is large in diameter (4m or more), heavy (30 tons or more), or has a long axial length (3m or more), the inversion work (standing the molding upright when it is horizontal, and returning it to its horizontal position after measurement) is hard work.

[0006] Furthermore, in either method, if the measurement results show that the inner and outer diameters or the radius of curvature are not within the target range, the molded product must be reattached to the bending rolls and corrected (rerolled), and a large amount of labor is required for the work of reattaching the molded product to the bending rolls and removing it after rerolling.

[0007] In contrast, by using the curvature radius measurement system proposed by the present applicant in Patent Document 1, it is possible to check the inner and outer diameters and curvature radius of the molded product without removing the molded product from the bending rolls after molding is completed.

[0008] That is, the curvature radius measurement system of Patent Document 1 measures the plate thickness t of the arc-shaped plate-like part of the article, the length along the circumferential direction between two first reference points on the concave arc surface (hereinafter also referred to as the "inner arc length") L1, and the length along the circumferential direction between two second reference points on the convex arc surface facing each of the first reference points in the plate thickness direction (hereinafter also referred to as the "outer arc length") L2, and calculates the curvature radius r = (L1 · t) / (L2 - L1) of the concave curved surface of the plate-like part. In the case of a cylindrical article, the inner diameter (2 × r) and the outer diameter (2 × r + 2 × t) can be easily obtained from the curvature radius r. Therefore, if this curvature radius measurement system is incorporated into a bending roll and the inner and outer diameters and curvature radius of the molded product are measured after molding is completed, the load and cost of the work of checking the inner and outer diameters and curvature radius of the molded product can be significantly reduced. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] JP 2020-51832 A Summary of the Invention [Problem to be solved by the invention]

[0010] When measuring the radius of curvature of a formed product using a bending roll incorporating the radius of curvature measurement system of Patent Document 1, the lower rolls are rotated while the formed product is held between the upper roll and each lower roll even after forming is completed, and the inner arc length L1 and the outer arc length L2 are measured using a known distance sensor, etc. At this time, the upper roll and each lower roll must be set at a position where they can hold the formed product without plastically deforming it.

[0011] However, when the upper roll and the lower rolls are held at set positions during measurement of the inner arc length L1 and the outer arc length L2 of the molded product, the load with which the upper roll presses the molded product varies depending on the circumferential position of the molded product, and this load variation causes measurement errors, which in turn lead to errors in the measurement results of the radius of curvature of the molded product.

[0012] Therefore, an object of the present invention is to enable the inner and outer diameters or the radius of curvature of a formed product to be measured with high accuracy using bending rolls. [Means for solving the problem]

[0013] In order to solve the above problems, the present invention provides a bending roll that includes an upper roll and a pair of lower rolls disposed on both the front and rear sides of the upper roll, and that rotates and drives the lower rolls while holding a metal sheet between the upper roll and the lower rolls, thereby bending the metal sheet while moving it back and forth to form a cylindrical or R-shaped product. The bending roll measures the sheet thickness t of the product, and holds the product between the upper roll and the lower rolls, and the upper roll presses the product. While controlling the vertical position of the upper roll so as to keep the load constant, the lower rolls are rotated to measure the length (inner arc length) L1 along the circumferential direction between any two first reference points on the concave arc surface of the molded product, and the length (outer arc length) L2 along the circumferential direction between two second reference points on the convex arc surface that face each of the first reference points in the thickness direction, and the measurement result is used to calculate t×L1 / (L2-L1) as the measured value of the radius of curvature of the concave curved surface of the molded product.

[0014] According to the above-mentioned configuration, after the completion of forming, the inner and outer diameters and the radius of curvature of the formed product can be confirmed without removing the formed product from the bending roll. Moreover, since the inner and outer arc lengths of the formed product are measured while controlling the vertical position of the upper roll so that a constant load is applied to the formed product from the upper roll, the measurement error is smaller than when the positions of the upper and lower rolls are kept constant, and the measurement accuracy of the radius of curvature and the inner and outer diameters of the concave curved surface of the formed product calculated from the measurement results can be improved.

[0015] Furthermore, when the measured value of the radius of curvature of the molded product or the measured values ​​of the inner and outer diameters calculated from the radius of curvature are larger than the target value, the upper roll is held at a correction position calculated from the difference between the measured value and the target value, and correction molding is performed on the molded product, thereby reducing the load of the correction work on the molded product. Effect of the Invention

[0016] As described above, in the bending roll of the present invention, after the forming of the metal plate is completed, the inner arc length and outer arc length of the formed product are measured while controlling the vertical position of the upper roll so that a constant load is applied to the formed product from the upper roll, and the radius of curvature is calculated from the measurement results. Therefore, the measurement error of the inner arc length and outer arc length is small, and the radius of curvature and inner and outer diameters of the formed product can be measured with high accuracy. [Brief description of the drawings]

[0017] [Figure 1] FIG. 3 is a front view of the bending roll according to the embodiment; [Diagram 2] Right side view of Figure 1 [Diagram 3] Left side view of Figure 1 [Figure 4] Schematic diagram of the measurement process for the bending roll in FIG. 1 [Diagram 5] An explanatory diagram of the measuring device used to carry out the measurement operations shown in FIG. [Figure 6] Flowchart of curvature radius measurement and correction forming in bending roll in Fig. 1 DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. As shown in Figs. 1 to 3, this bending roll includes an upper roll 1, a pair of lower rolls 2 arranged parallel to the upper roll 1 on both front and rear sides below the upper roll 1, a motor case 3 incorporating a motor (not shown) that rotates and drives each lower roll 2, left and right upper frames 4 and 5 that support both ends of the upper roll 1, and a lower frame 6 that supports both ends of each lower roll 2. Each lower roll 2 is supported at its axial center by a backup roll (not shown) from both front and rear sides below. The upper roll 1 is moved to a front-rear direction position according to the forming conditions, and the lower rolls 2 are rotated while the metal plate is sandwiched between the upper roll 1 and each lower roll 2, thereby bending the metal plate while moving it back and forth. Note that a measuring device for measuring the radius of curvature, which will be described later, is not shown in Figs. 1 to 3.

[0019] Each of the upper frames 4, 5 is formed in a roughly gate-like shape, with its legs disposed between a bearing 6a provided on the top surface of the lower frame 6 and support plates 7 fixed to the front and rear surfaces of the lower frame 6, and a support shaft 8 extending in the front-rear direction is passed through the bearing 6a and the front and rear support plates 7. The support shaft 8 is fixed to the bearing 6a and support plates 7 of the lower frame 6, and the legs of each of the upper frames 4, 5 are slidable relative to the support shaft 8.

[0020] As a result, the upper frame 4 on the left side in Fig. 1 is movable back and forth, and is a tipping frame that moves away from one end of the upper roll 1 and rotates (tip-over) to the left when removing the formed metal plate (hereinafter also referred to as the "formed product"). On the other hand, the upper frame 5 on the right side in Fig. 1 cannot rotate away from the other end of the upper roll 1 and can only move back and forth because the other end of the upper roll 1 extends outward in the axial direction.

[0021] Moreover, a hydraulic cylinder 9 is attached to the upper end of each of the upper frames 4, 5 with its rod 9a facing downward, and the lower end of the rod 9a is connected to a bearing 10 that rotatably supports an end of the upper roll 1, so that the upper roll 1 is raised and lowered by the operation of both hydraulic cylinders 9. The rise of the upper roll 1 is regulated by a gate-shaped stopper 11 fixed to the lower frame 6 in a state of straddling the extension part 1a at the other end of the upper roll 1.

[0022] The closed end of a two-stage hydraulic cylinder 12 is rotatably attached to the lower part of one end surface of the lower frame 6. The tip of a second-stage rod 12a of the hydraulic cylinder 12 is rotatably connected to the upper frame 4 as a tipping frame, so that when the molded product is removed, the hydraulic cylinder 12 rotates and expands and contracts, causing the upper frame 4 to tip and return to its original position.

[0023] This bending roll has the above-mentioned configuration, and after the forming of the metal plate is completed, the radius of curvature is measured without removing the formed product, and corrections are made as necessary based on the measurement results, thereby obtaining a formed product having the desired radius of curvature.

[0024] Here, the radius of curvature of the molded product is measured as shown in Figure 4 by measuring the thickness t of the molded product W, clamping the molded product W between the upper roll 1 and each lower roll 2, and rotating each lower roll 2 while controlling the vertical position of the upper roll 1 so that the load with which the upper roll 1 presses the molded product W is constant (so that a constant load is applied to the molded product W), thereby measuring the length (inner arc length) L1 along the circumferential direction between two first reference points A, A' on the concave arc surface in a part of the circumferential direction of the molded product W, and the length (outer arc length) L2 along the circumferential direction between two second reference points B, B' on the convex arc surface that faces each of the first reference points A, A' in the thickness direction, and calculating t × L1 / (L2-L1) from the measurement results to obtain the measured value r of the radius of curvature of the concave curved surface of the molded product W.

[0025] In this embodiment, the molded object W is cylindrical, and its dimensions are confirmed by comparing the inner diameter d (= 2 × r) or outer diameter D (= 2 × r + 2 × t) calculated from the measured value r of the radius of curvature with its target value. However, if the molded object has an R-shape, it is sufficient to compare the measured value r of the radius of curvature with its target value.

[0026] In addition, the plate thickness t of the molded product W can be measured using a measuring tool or a known plate thickness gauge, and the inner arc length L1 and the outer arc length L2 can be measured using a measuring device including a known distance sensor that measures the distance along a specified path.

[0027] 5 shows a measuring device for measuring the arc lengths L1 and L2 of the formed product W in the bending roll of the embodiment. The measuring device for the inner arc length L1 uses the upper roll 1 as a distance sensor, and includes a pulley 13 attached to the shaft end of the upper roll 1, a pulley 15 rotatably attached to the fixed upper frame 5 (not shown) via a mounting base 14, a timing belt 16 wound between the pulleys 13 and 15, and a pulse encoder 17 for detecting the rotation of the pulley 15 on the upper frame 5 side, and obtains L1 from the detection result of the pulse encoder 17.

[0028] On the other hand, the measuring device for the outer arc length L2 comprises a spring 19 attached via a stand 18 to the lower frame 6 between a pair of lower rolls 2, a measuring roller 20 pressed against the convex arc surface of the molding W by the spring 19, and a pulse encoder 21 that detects the rotation of the measuring roller 20, and L2 is calculated from the detection result of the pulse encoder 21.

[0029] Next, a method for checking the dimensions of a cylindrical product using the bending roll and a method for correcting the shape will be described. In this embodiment, the dimensions of the product are checked and corrected as necessary by a sequencer that controls the normal forming operation and the temporary welding operation of the joints of the product. The specific processing procedure of the control by the sequencer is shown in Figure 6.

[0030] In this control, before starting the molding operation, the measurement conditions, i.e., a constant load (preload load) to be applied to the molded product during measurement, the measurement distance, the number of measurement points, and the target inner diameter d0 of the molded product are set (step S1). In this embodiment, the number of measurement points is three or more, and the measurement distance is about 100 to 200 mm per point, but the measurement distance can be set arbitrarily.

[0031] Then, after the normal forming (step S2) is completed and the joints of the formed product are pre-welded (step S3), the operator is asked to select whether the corrective forming performed by this control should be performed after each measurement or after the entire circumference measurement (step S4), and the corrective forming method is determined (step S5), and the subsequent processing procedure is decided.

[0032] First, when correcting molding for each measurement, for the first measurement point on the molded product, the upper roll is moved to the measurement start position (step S6), and with a preload load applied to the molded product (step S7), each lower roll is rotated to simultaneously measure the inner arc length L1 and outer arc length L2 of the molded product at the set measurement distance (step S8). From this measurement value and the separately measured plate thickness t of the molded product, t × L1 / (L2-L1) is calculated to obtain the measured value r of the radius of curvature of the concave curved surface of the molded product, and 2 × r is used to obtain the measured value d of the inner diameter of the molded product (step S9).

[0033] During the measurements in steps S8 and S9, the vertical position of the upper roll is controlled by an electromagnetic proportional control valve connected to a hydraulic cylinder for raising and lowering the upper roll so that the load with which the upper roll presses the molded product is constant. This reduces the measurement error of the inner arc length L1 and the outer arc length L2, allowing the inner diameter d of the molded product to be measured with high accuracy.

[0034] Next, the measured value d of the inner diameter calculated in step S9 is compared with the target value d0 (step S 10 Note that the actual target value d0 has a certain tolerance.

[0035] Step S 10If the result of the judgment in step S2 is that the measured value d of the inner diameter is greater than the target value d0, the correction position of the upper roll is calculated based on the difference between the measured value d and the target value d0, and the upper roll is moved to the correction position to perform correction molding of the molded product (step S3). 11 If the measured value d is smaller than the target value d0, the molding cannot be corrected, so the molding is corrected after it is removed from the bending roll. After the correction, the inner diameter is measured again (steps S6 to S9), and the step S 10 Return to step S. 10 If the measured value d of the inner diameter is equal to or smaller than the target value d0, the process moves to measurement of the next measurement point (return to step S6).

[0036] The above measurement and correction molding processes (steps S6 to S 11 After repeating the above steps for the number of measurement points, the upper roll is moved to the correction position at the measurement point where the measurement value d closest to the inner diameter target value d0 is obtained (hereinafter referred to as the "final correction position"), and the entire circumference is corrected and shaped (step S 12 ), and control ends. By maintaining the upper roll at a fixed position (final correction position) and correcting the entire circumference, it is possible to reduce unevenness in the inner diameter due to the measurement points after correction molding for each measurement.

[0037] On the other hand, when corrective molding is performed after the entire circumference measurement, the measurement is performed at the first measurement point of the molded product in the same manner as when corrective molding is selected for each measurement (step S 13 ~S 16 ), when the measurement is completed, the measured value d is stored and then step S 15 In other words, since correction molding is not performed for each measurement, step S is repeated for the second and subsequent measurement points. 13 , S 14 No processing is required.

[0038] The above measurement process (Step S 15 , S 16 ) is repeated, and when the measurement of all the measurement points is completed, the measurement value d of the inner diameter is compared with the target value d0 for each measurement point in order (step S 17), and corrective molding is performed only when the measured value d is greater than the target value d0 (step S 18 ). Then, step S 18 Determine whether or not there is a measurement point (correction point) where correction molding was performed (step S 19 ), if there are any corrections, go to step S 13 Return to.

[0039] The above measurement and correction molding process (Step S 13 ~S 19 ) is repeated, and when there is no more to be corrected, the upper roll is moved to the final correction position, and the entire circumference is corrected and molded (step S 20 ), and control ends.

[0040] When the inner diameter measurement results are displayed on the screen of a control device, the average value of the measurement values ​​d at all measurement points is usually used as the displayed value, but it is also possible to display the average value for any selected measurement points.

[0041] In the above-mentioned measurement and correction molding control, correction molding is performed so that the measured value of the inner diameter of the molded product is equal to or less than the target value, but the control target may be the outer diameter of the molded product. Also, if the molded product has an R-shape, the temporary welding (step S3) is eliminated and the control target is the curvature radius of the molded product.

[0042] As described above, with this bending roll, after the completion of normal forming, it is possible to measure the inner and outer diameters and the radius of curvature of the formed product W and check whether they meet the target values ​​without removing the formed product W. Moreover, in measuring the inner and outer diameters and the radius of curvature of the formed product W, the inner arc length L1 and the outer arc length L2 of the formed product W are measured while controlling the vertical position of the upper roll 1 so that a constant load is applied to the formed product W. Therefore, the measurement error is smaller than when the measurement is performed while the positions of the upper and lower rolls are kept constant, and the measurement accuracy of the radius of curvature and the inner and outer diameters calculated from the measurement results is also higher.

[0043] Here, in the above-described embodiment, the measuring device for the inner arc length L1 detects the rotation transmitted from the upper roll 1 via the pulleys 13, 15 and the timing belt 16. However, instead of this, it is also possible to use a measuring roller that is pressed against the outer circumferential surface of the shaft end of the upper roll and detects the rotation of the measuring roller.

[0044] In addition, the measuring device for the outer arc length L2 in the embodiment detects the rotation of the measuring roller 20 pressed against the convex arc surface of the molding W by the spring 19, but the measuring roller 20 may be pressed against the molding W by an air cylinder or a hydraulic cylinder instead of the spring 19.

[0045] Furthermore, in this bending roll, correction molding is performed on areas of the molded product W where the measured values ​​of the radius of curvature or the inner and outer diameters are larger than the target values, either in parallel with the measurement of each measurement point, or all at once after the measurements of all measurement points have been performed, thereby reducing the burden of the correction work for the molded product W.

[0046] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, not by the above meaning, and is intended to include all modifications within the scope and meaning equivalent to the claims.

[0047] In addition, by using the bending roll of the present invention, it is possible to accurately measure the inner and outer diameters of cylindrical molded products such as welded pipes on the market and the curvature radius of R-shaped molded products, and perform corrective molding (rerolling). [Explanation of symbols]

[0048] 1 Upper roll 2 Lower roll 4, 5 Upper frame 6 Lower Frame 9 Hydraulic Cylinders 13, 15 Pulley 16 Timing belt 17, 21 Pulse encoder 19 Spring 20 Measuring roller W Molding

Claims

1. A bending roll includes an upper roll and a pair of lower rolls disposed on both the front and rear sides of the upper roll, and the lower rolls are driven to rotate in a state in which a metal sheet is sandwiched between the upper roll and each lower roll, thereby bending the metal sheet while moving it back and forth to form a cylindrical or R-shaped product, The plate thickness t of the formed product is measured, and the formed product is sandwiched between the upper roll and each lower roll. While controlling the vertical position of the upper roll so that the load with which the upper roll presses the formed product is constant, each lower roll is rotated to measure the length L along the circumferential direction between any two first reference points on the concave arc surface of the formed product. １ and a length L along the circumferential direction between two second reference points on a convex arc surface that faces each of the first reference points in the plate thickness direction. ２ and from the measurement results, t×L １ / (L ２ -L １ ) is calculated as a measured value of the radius of curvature of the concave curved surface of the molded product.

2. The bending roll according to claim 1, characterized in that, when the measured value of the radius of curvature of the molded product or the measured values ​​of the inner and outer diameters calculated from the radius of curvature are larger than the target values, the upper roll is held at a correction position calculated from the difference between the measured value and the target value, and correction molding is performed on the molded product.

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