Fin forming method

Abstract

To provide a fin molding method that reduces the number of stages in a multi-stage molding roller device, and can mold a metal sheet into an irregular fin shape.SOLUTION: A fin molding method presses a belt-like metal sheet by a plurality of roller pairs on both sides having an irregularity formed on a roller cylindrical surface and with the metal sheet pinched therebetween, and molds peaks and valleys extending in a longer direction alternately along a shorter direction. The roller pairs have a rotation axis parallel to the shorter axis, and are located along a transportation direction from a carry-in side in order. When a point, at which a distance from one end in the shorter direction of the metal sheet before molding and a distance from the other end are respectively kept constant, is so made as to be a reference point and a line in the longer direction, which is continuously formed by the reference point in association with transportation, is so made as to be a reference line, pressing is performed along the reference point and the reference line without a clearance between the metal sheet and the roller pairs, and pressing is performed along a line parallel to the reference line while keeping the clearance at a point other than the reference point, and width drawing is gradually performed around the reference line, at a gathering step S1. At a fin molding step S2, peaks and valleys are molded.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to a fin forming method.

Background Art

[0002] Conventionally, fin forming methods for finned tube heat exchangers and the like are known. For example, Patent Document 1 discloses a "method for manufacturing corrugated fins" including a "preliminary bending step of bending a coil material by a pair of rollers to form a flat portion and a plurality of recessed groove portions that are recessed in parallel with each other from the flat portion at a predetermined pitch".

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Conventionally, a sheet-like metal material has been passed through a multi-stage forming roller device of at least 10 or more stages (for example, FIG. 8 of the present application, FIG. 3 of Patent Document 1 "roll forming machine for preliminary forming", etc.) to form a concavo-convex fin shape (FIG. 4 of Patent Document 1).

[0005] During forming, a complex resistance force is generated in the material, which causes wrinkles and breaks. If an attempt is made to form it in one go with a small number of stages, the resistance force generated in the material becomes large and the quality deteriorates. Therefore, it has been necessary to form one peak (one valley) per stage, and the number of stages of the multi-stage forming roller device could not be reduced.

[0006] An object of the present invention is to provide a fin forming method that can reduce the number of stages of a multi-stage forming roller device and form a metal sheet into a concavo-convex fin shape in view of the above problems.

Means for Solving the Problems

[0007] The present invention is a fin-forming method that uses a plurality of roller pairs (11, 12, 13, 14, 25, 26, 27), each consisting of a pair of rollers having irregularities formed on the cylindrical surface of the rollers and forming a pair on both sides of a strip-shaped metal sheet (7), to press the conveyed metal sheet from both sides, thereby alternately forming peaks and valleys (71) extending in the longitudinal direction (Dy) of the metal sheet parallel to the conveying direction, along the short direction (Dx) of the metal sheet, and includes a gathering step (S1) and a fin-forming step (S2).

[0008] Multiple roller pairs have their rotation axes parallel to the shorter direction and are arranged along the conveying direction. Of the multiple roller pairs, the first group of roller pairs (11, 12, 13, 14) are arranged in order from the input side in the conveying direction.

[0009] Here, for the metal sheet before molding, a point where the distance from one end in the shorter direction and the distance from the other end are kept constant is defined as the reference point (P), and the longitudinal line continuously formed by the reference point as the metal sheet is transported is defined as the reference line (L).

[0010] During the aligning step, the first group of roller pairs press the metal sheet at the reference point along the reference line without any clearance between the metal sheet and each roller pair, and press the metal sheet at points other than the reference point along a line parallel to the reference line while maintaining clearance between the metal sheet and each roller pair, thereby gradually aligning the metal sheet from both sides in the shorter direction, centering on the reference line.

[0011] In the fin forming step, after the aligning step, the metal sheet after width aligning is gradually pressed by the second group of roller pairs (25, 26, 27), which are the roller pairs of the first group among the multiple roller pairs, to form peaks and valleys.

[0012] In light of the above problems, the inventors focused on the fact that conventional techniques perform joining and forming together, which results in a large resistance force within the material. They investigated whether the number of stages could be reduced by separating joining and forming.

[0013] As a result, the fin forming method of the present invention separates the pull resistance generated by the shrinkage of the material in the short direction from the resistance generated by the forming of peaks and valleys. By completing the width adjustment of the metal sheet in the adjustment step and forming the peaks and valleys in the fin forming step, it is possible to reduce the number of stages in the multi-stage forming roller device while reducing quality defects such as wrinkles and breakage, and to form the metal sheet into an uneven fin shape. [Brief explanation of the drawing]

[0014] [Figure 1] A plan view of a fin molding apparatus according to one embodiment. [Figure 2] A schematic diagram of the fin forming method according to one embodiment is shown in (a) before forming, (b) after the joining step, and (c) perspective view of the metal sheet during the fin forming step. [Figure 3] A cross-sectional view of a fin plate according to one embodiment. [Figure 4] A schematic diagram illustrating a fin molding method in one embodiment, step by step. [Figure 5] A diagram illustrating a first group of roller pairs in one embodiment. [Figure 6] A diagram illustrating a second group of roller pairs in one embodiment. [Figure 7] A flowchart of a fin molding method according to one embodiment. [Figure 8] A plan view of the comparative example fin molding apparatus (multi-stage molding roller apparatus). [Figure 9] A schematic diagram illustrating the fin molding method of a comparative example step by step. [Figure 10] (a) A schematic diagram showing the stress generated within the material during fin formation in the comparative example and (b) a case where the number of layers is reduced in the comparative example. [Figure 11] A schematic diagram illustrating the stress generated within the material during fin formation in one embodiment. [Modes for carrying out the invention]

[0015] Hereinafter, a fin forming method S according to an embodiment of the present invention will be described based on the drawings. The first named terms with reference signs are shown enclosed in "". When a plurality of reference signs consist of consecutive numbers in a row, they are abbreviated as "~" as appropriate for readability.

[0016] <One embodiment> The "fin forming method S" of one embodiment uses a plurality of roller pairs 11, 12, 13, 14, 25, 26, 27, which are a set of roller pairs that form a pair on both sides sandwiching a strip-shaped "metal sheet 7" having concavities and convexities formed on the "roller cylindrical surface C", as a constituent unit. By pressing the metal sheet 7 being conveyed from both sides, "ridges and valleys 71" extending in the "longitudinal direction Dy" of the metal sheet 7 parallel to the "conveying direction Da" are alternately formed along the "lateral direction Dx" of the metal sheet 7, and includes a "gathering step S1" and a "fin forming step S2".

[0017] The plurality of roller pairs 11 to 14, 25 to 27 have rotation axes parallel to the lateral direction Dx and are arranged along the conveying direction Da. Among the plurality of roller pairs 11 to 14, 25 to 27, the "first group of roller pairs 11, 12, 13, 14" are arranged in order from the loading side in the conveying direction Da.

[0018] A "fin forming apparatus 100" used in the fin forming method S of one embodiment is shown in FIG. 1. The fin forming apparatus 100 includes a plurality of roller pairs 11 to 14, 25 to 27, a "sheet conveyor 107", and a "roller driving device 109". In one embodiment, the "plurality of" roller pairs are seven roller pairs. Although the shapes of the roller pairs are different from each other, they are abbreviated in FIG. 1 and will be described later.

[0019] The metal sheet 7 is formed into a "fin plate 72" by the fin forming method S using the fin forming apparatus 100. Hereinafter, the direction orthogonal to the horizontal plane formed by the lateral direction Dx and the longitudinal direction Dy is the "vertical direction Dz", the length of the fin plate 72 in the lateral direction Dx is the "width Lx", and the length of the fin plate in the vertical direction Dz (= the length of the ridges and valleys 71 in the vertical direction Dz) is the "height Lz".

[0020] The sheet conveyor 107 is a device that delivers and conveys, for example, a metal sheet 7 wound into a roll of equal width. In one embodiment, the metal sheet 7 is "sheet-shaped aluminum 7". The sheet conveyor 107 conveys the sheet-shaped aluminum 7 from left to right in Figure 1 along the conveying direction Da.

[0021] The multiple roller pairs 11-14 and 25-27, each containing seven roller pairs, include "the first group of roller pairs 11, 12, 13, and 14" and "the second group of roller pairs 25, 26, and 27". As described later, the first group of roller pairs 11-14 perform the shaping step S1, and the second group of roller pairs 25-27 perform the fin forming step S2.

[0022] Before providing a detailed explanation, we will outline the fin forming method S. Figure 2 shows the forming process of the sheet-like aluminum 7 at each stage. Figure 2(a) shows the "unformed sheet-like aluminum 70" along with a simplified representation of the roller pair. Here, the roller pair 11 is shown along with the roller cylindrical surface C, the "two rotation axes R111, R112" and the "concave and convex surfaces V111, V112".

[0023] Each roller pair is individually labeled, but in the following, these will be generalized as needed and referred to as "roller pair nn" (where nn is the label for each roller pair). In one embodiment, the plane containing the "two rotation axes Rnn1, Rnn2" of each roller pair nn (where nn is the label for each roller pair) is perpendicular to the sheet aluminum 7, which includes the unformed sheet aluminum 70.

[0024] Figure 2(b) shows the sheet-shaped aluminum 7 after the unformed sheet-shaped aluminum 70 has been brought into width in step S1. Thus, step S1 is a step to bring the sheet-shaped aluminum 7 into width in the shorter direction Dx, thereby aligning it with the width Lx of the fin plate 72 that will be completed in fin forming step S2, before performing fin forming step S2.

[0025] Figure 2(c) shows the sheet-like aluminum 7 midway through the fin forming step S2 (after the "pressing step S25," which is one of the "individual pressing steps" described later). Thus, the fin forming step S2 is a step in which the sheet-like aluminum 7, which has been previously brought to the width Lx of the fin plate 72 in the joining step S1, is pressed in stages along the vertical direction Dz to form peaks and valleys 71, thereby completing the fin plate 72. The completed fin plate 72 is shown in Figure 3.

[0026] Next, the specific fin forming process is shown in Figure 4. Hereafter, the individual pressing steps for each roller pair corresponding to the multiple roller pairs 11-14 and 25-27 will be referred to as "pressing steps S11, S12, S13, S14, S25, S26, and S27," respectively. Furthermore, the shapes of roller pairs 12 and 14 corresponding to pressing steps S12 and S14 are shown in Figure 5, and the shapes of roller pairs 25-27 corresponding to pressing steps S25-S27 are shown in Figure 6, along with the convex and concave shapes Vnn1 and Vnn2 (nn: 25-27) of each roller pair nn. Finally, the flowchart of the fin forming method S is shown in Figure 7.

[0027] As shown in Figures 2(a) and the top row of Figure 4, for the unformed sheet-like aluminum 70, a point where the distance from one end 701 and the distance from the other end 702 in the short direction Dx are kept constant is defined as the "reference point P". The longitudinal line continuously formed by the reference point P as the sheet-like aluminum 7 moves from the unformed sheet-like aluminum 70 state to the fin plate 72 as the sheet-like aluminum 7 is gradually formed is defined as the "reference line PP". Here, the distance from one end 701 is "α" and the distance from the other end 702 is "β". The length of the unformed sheet-like aluminum 70 in the short direction is "α + β".

[0028] At this time, in the aligning step S1 (=pressing steps S11~14), the first group of roller pairs 11~14 from among the multiple roller pairs 11~14 and 25~27 press the unformed sheet-shaped aluminum 70 at the reference point P along the reference line PP without any clearance between the sheet-shaped aluminum 7 and each roller pair, and presses the unformed sheet-shaped aluminum 70 at points other than the reference point P along a line parallel to the reference line PP while maintaining clearance between the sheet-shaped aluminum 7 and each roller pair (Figure 4 "Alignment stress Fx"). As a result, the unformed sheet-shaped aluminum 70 is gradually aligned in width from both sides in the short direction Dx, centered on the reference line PP, to match the width Lx of the fin plate 72.

[0029] As shown in Figures 2(a)-(b) and the pressing steps S11-14 in Figure 4, only the reference point P and the reference line PP are pressed by the first group of roller pairs 11-14 so that the positions of the sheet-shaped aluminum 7 in the short direction Dx and vertical direction Dz do not change during transport (=forming). On the other hand, a clearance is secured between each roller pair for parts other than the reference point P and the reference line PP, and these parts can move somewhat freely within the clearance range, so as a result the sheet-shaped aluminum 7 can be moved towards the reference point P and the reference line PP.

[0030] To perform the aligning step S1, the first group of roller pairs 11-14 have gentle irregularities Vnn1 and Vnn2 (nn: 11-14) formed on the cylindrical surface C of the rollers, as shown in Figure 5, and their outer diameters are not constant. The upper and lower rollers face each other at the reference point P and reference line PP, leaving a length equal to the thickness of the sheet-like aluminum 7. As a result, during the aligning step S1, the upper and lower rollers are always in contact with the sheet-like aluminum 7 from both sides at the reference point P and reference line PP, preventing the portion of the sheet-like aluminum 7 corresponding to the reference point P and reference line PP from moving up, down, left, or right. At the same time, to allow for smooth aligning, sufficient clearance is provided between the sheet-like aluminum 7 and the rollers other than at the reference point P and reference line PP.

[0031] In the subsequent fin forming step S2 (=pressing steps S25~27), ​​after the joining step S1, the sheet-like aluminum 7, after width joining, is gradually pressed along the vertical direction Dz by the second group of roller pairs 25~27, which are the roller pairs of the first group among the multiple roller pairs 11~14 and 25~27, and peaks and valleys 71 of height Lz are sequentially formed along the short direction Dx to complete the fin plate 72.

[0032] As shown in Figures 2(b) to (c) and S25 to S27 in Figure 4, in the fin forming step S2, since the sheet aluminum 7 already has the width Lx of the fin plate 72, it is only necessary to press it along the vertical direction Dz, and the only operation performed is to adjust the length of the vertical direction Dz of the fin plate 72 to the height Lz.

[0033] To perform the fin forming step S2, the roller pairs 25-27 of the second group have gentle irregularities Vnn1 and Vnn2 (nn:25-27) formed on the cylindrical surface C of the rollers, similar to the roller pairs 11-14 of the first group. However, since the width adjustment work is completed in the adjustment step S1, they are given a regular shape, as shown in Figure 6, to perform only fin forming by gradually reducing the height (depth) of the peaks and valleys 71. In addition, the clearance between the upper and lower rollers is kept to a minimum, and in the fin forming step S2, each roller pair and the sheet-like aluminum 7 are almost in contact and pressed together to complete the fin shape.

[0034] The following describes the solution to the problems of fin forming method S with reference to a comparative example. A multi-stage forming roller apparatus (conventional technology) of the comparative example is shown in Figure 8. The fin forming method in the comparative example is shown in Figure 9 using the same method as in Figure 4 (fin forming method S). Here, one pair of rollers that make up one step is counted as "one stage". Furthermore, the stress conditions within the material during fin forming are shown in Figure 10 for the comparative example and in Figure 11 for fin forming method S.

[0035] As described in paragraph

[0005] , in fin forming, complex resistance forces that can cause wrinkles and fractures are generally generated within the material. In the comparative example of the prior art, attempting to form in a small number of stages at once results in a large pull resistance in the short direction, leading to poor molding quality. As a result, only one peak (one valley) can be formed per stage (Figure 9), requiring a multi-stage molding roller device with at least 10 roller pairs (Figure 8).

[0036] As shown in Figure 10(a), in the comparative example, material pull-in occurs in the short-side direction of the material at each stage. At this time, the width in the short-side direction is always reduced before and after forming at each stage. Simultaneously with this reduction in the short-side direction, peaks and valleys are formed alternately at one location on each side. In other words, in the comparative example, the material gathering process (gathering stress Fx in Figure 9) and the fin forming process (stress along the vertical direction Dz) occur simultaneously at multiple locations each time, and the gathering stress and fin forming stress within the material are combined and become larger each time.

[0037] Therefore, in the comparative example, as shown in Figure 10(b), when attempting to reduce the number of stages and form multiple peaks and valleys at once, fractures are more likely to occur at locations where the arrows (stresses) point in opposite directions, moving away from each other. For this reason, it is thought that in the comparative example, it was difficult to reduce the tension resistance around the deformation area, and therefore difficult to reduce the number of stages.

[0038] Therefore, the inventors considered whether the number of steps could be reduced in the fin forming method S by separating the material gathering process (gathering step S1) and the fin forming process (fin forming step S2), as shown in Figure 4, and by performing and completing the gathering process in the first half of the forming process, and then performing only the fin forming process in the second half of the forming process.

[0039] As a result, in the fin forming method S, as shown in Figure 11, the stress associated with width adjustment is brought forward and concentrated in the adjustment step S1, and in the fin forming step S2, no stress other than fin forming stress is generated. This allows for a significant reduction in the number of steps without causing fracture due to stress concentration, and enables fin forming with the same quality as the comparative example.

[0040] In step S1, the distance (diameter) from the axis of rotation differs depending on the location in areas with different molding heights (areas with clearance), resulting in differences in peripheral speed within each roller of the roller pair. Therefore, the clearance between the material and the roller is adjusted according to the radial distance of the roller cylindrical surface C from the axis of rotation. The clearance is changed between areas with high peripheral speed (areas with large outer diameter) and areas with low peripheral speed (areas with small outer diameter) to absorb the difference in peripheral speed.

[0041] With the above configuration, the fin forming method S of one embodiment can form a metal sheet into an uneven fin shape while reducing the number of stages in a multi-stage forming roller apparatus by separating the pull resistance that occurs as the material shrinks in the short direction from the resistance that occurs as the peaks and valleys are formed.

[0042] <Other Embodiments> In the above-described embodiment, an example was presented in which the shaping step was configured with three roller pairs and the fin forming step with four roller pairs. However, the number of steps in each step is not limited to the above example and may be changed as appropriate depending on the shape of the desired fin plate.

[0043] Thus, the present invention is not limited to the embodiments described above, and can be implemented in various forms without departing from its spirit. [Explanation of symbols]

[0044] 11, 12, 13, 14, 25, 26, 27 Multiple roller pairs 11, 12, 13, 14 Laura pairs of Group 1, 25, 26, 27 Laura pairs of Group 2 7 Metal sheet (=sheet-shaped aluminum), 71 peaks and valleys Dx: Short direction, Dy: Long direction (≒ Conveying direction), P: Reference point, PP: Reference line S1 Attachment step, S2 Fin forming step

Claims

1. A fin forming method comprising a plurality of roller pairs (11, 12, 13, 14, 25, 26, 27) each comprising a pair of rollers having irregularities formed on the cylindrical surface of the rollers and forming a pair on both sides of a strip-shaped metal sheet (7), wherein the conveyed metal sheet is pressed from both sides, and peaks and valleys (71) extending in the longitudinal direction (Dy) of the metal sheet parallel to the conveying direction are alternately formed along the short direction (Dx) of the metal sheet, wherein The plurality of roller pairs have their rotation axes parallel to the shorter direction and are arranged along the conveying direction, and the first group of roller pairs (11, 12, 13, 14) are arranged in order from the input side in the conveying direction. If, with respect to the metal sheet before molding, a point where the distance from one end and the distance from the other end in the shorter direction are kept constant is defined as a reference point (P), and the longitudinal line continuously formed by the reference point as the metal sheet moves during transport is defined as a reference line (PP), The first group of roller pairs press the metal sheet at the reference point along the reference line without any clearance between the metal sheet and each roller pair, and presses the metal sheet at points other than the reference point along a line parallel to the reference line while maintaining clearance between the metal sheet and each roller pair, thereby moving the metal sheet in stages from both sides in the shorter direction towards the reference line (S1), After the aforementioned aligning step, the metal sheet after aligning is pressed in stages by the second group of roller pairs (25, 26, 27), which are the roller pairs of the first group among the plurality of roller pairs, to form the peaks and valleys in a fin forming step (S2), A fin molding method including the following.

2. The fin forming method according to claim 1, wherein in the joining step, the clearance between the metal sheet and the cylindrical roller surface of the first group of rollers is adjusted according to the radial distance of the cylindrical roller surface from the axis of rotation.

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