JPH02169131A - Manufacture of metallic cylindrical body - Google Patents

Abstract

PURPOSE:To secure the quality of a bent position, bending, etc., of an end part in a bending stage by press-forming bent flanges at both side ends of a metallic sheet stock when it is not worked at all. CONSTITUTION:In a 1st stage, the bend flanges 2, 3 at both side ends of the metallic sheet stock 1 are formed by press bending when the metallic sheet stock 1 is not worked at all. Therefore, the bent parts 2A, 3A of both flanges are formed all over the lengths at the same time without receiving unreasonable force in sure bending accuracy. Consequently, in a 3rd stage when the metallic sheet stock 1 is wound round a mandrel M and both bent flanges 2, 3 are put on top of each other, the bent parts 2A, 3A of both bent flanges 2, 3 are arranged in good accuracy and the bent positions and the bent lines, etc., of bent parts 2A, 3A of the bent flanges 2, 3 can be secured in quality. As a result, the product quality of a metallic cylindrical body S can be guaranteed in a forming time in the later stage.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of manufacturing a metal cylinder such as a shell constituting a muffler for an automobile.

[Conventional technology]

Generally, a metal cylindrical body made of a thin metal plate is manufactured by bending a cut metal thin plate into a cylindrical shape and connecting the side ends by welding or lock seaming. for example,
A device disclosed in Japanese Patent Application Laid-Open No. 195722/1983 is known (as shown in FIGS. 14 and 15).

In FIG. 14, in the first step (1), a steel plate A is pressed onto a mandrel M, wound around it, and bent into a U-shape. In the second step (2), one end A1 of steel+ff1A
is bent into a substantially L-shape, and the other end At is bent into a substantially dogleg shape. In this step, as shown in FIG. 15, one end A is connected to a pair of T-shaped rollers 101.
, 101. Further, the other end At is formed by a pair of rollers 102, 102 having a spherical shape.

In the third step (3), both ends of the steel plate A bent into a U-shape are pressed against the mandrel M by a spatula 103 and regulated. In the fourth step (4), one end Al of the steel plate A is pressed against the inside of the other end At by a pair of rollers (not shown) to overlap, and then the bent part A3 of the other end A2 is When one end A is bent upward, the process proceeds to the fifth step (5), where an overlapping portion A is formed. This overlapping portion A4 is folded down by lock seaming to obtain a metal cylinder S.

[Problem to be solved by the invention]

However, in the conventional method for manufacturing a metal cylinder, in the second step (2), the end A+ of the steel plate A bent into a U-shape is
, At, the rollers 101, 10
1 and rollers 102, 102, the ends A+ and At of the steel plate A are bent little by little along the longitudinal direction of the steel plate A, so that the ends At and Ax of the steel plate A are not simultaneously bent over the entire length. , can be forcibly bent. For this reason, there is a possibility that the polymerization state of the ends A+ and Az of the steel plate A may not be formed according to the design drawings. For example, steel plate A
The average value of the bending positions of the ends AI and Ax may be out of order, and the bending positions of the ends A+ and Az may vary.

Further, problems such as the bending lines along the longitudinal direction of the ends A and A2 becoming wavy occur. As a result, the above-mentioned defects may affect the quality in subsequent processes, and the metal cylindrical body S may be formed into a trumpet shape or a wave shape, and the product quality of the metal cylindrical body S may not be guaranteed. There is.

The present invention has been made to solve the above-mentioned problems, and its purpose is to improve the quality (average It is an object of the present invention to provide a method for manufacturing a metal plate body that can ensure the quality of the metal cylinder body (value, variation) and thereby guarantee the product quality of the metal cylinder body during molding in a subsequent process.

[Means for Solving the Problems] In order to achieve the above object, the present invention includes bending flanges having different flange lengths by press bending on both ends of a cut flat metal plate. After forming, this press-bent metal plate is wrapped around a mandrel, and the double-folded flanges are overlapped so that the tip side of the bent flange with the longer flange length protrudes from the bent flange with the shorter flange length. Next, the tip side of the bent flange with the longer flange length is folded back onto the bent flange with the shorter flange length to form an overlapping part, and this overlapping part is processed by lock seaming in the direction of the mandrel. It is folded and formed.

[For production]

In the present invention, the bent flanges at both ends of the metal plate are formed by press bending with the metal plate completely unprocessed. The bending accuracy of the bent portions of the double-folded flanges is ensured.

Therefore, the metal plate body can be wound around a mandrel and the double-folded flanges can be overlapped with high accuracy, and the accuracy of the double-folded flanges is the basis for ensuring quality in subsequent processes.

C Example] Embodiments of the present invention will be described below with reference to the drawings.

1 to 12, a method for manufacturing a metal cylindrical body according to an embodiment of the present invention will be explained as applied to a muffler shell. Figure 1 shows the first step, Figure 2 shows the second process, Figure 3 shows the first step,
Figure 12 shows the 3rd process, Figure 4 shows the 4th process, Figure 5 shows the 5th process, Figure 6 shows the 6th process, Figure 7 shows the 7th process, and Figure 8 shows the 7th process. 9 shows the 9th step, FIG. 10 shows the 10th step, and FIG. 11 shows the 11th step. According to this example, the muffler shell S shown in FIG. 13 was molded. Ru.

In the first step shown in Fig. 1, 1 is a flat metal plate, and this metal plate 1 is formed by press bending using a metal material that has been punched to the required dimensions by trimming. That's both 01! At the l end, bent flanges 2 and 3 are formed at an obtuse angle with respect to the flat plate portion IA, and the length of the bent flange 2 is longer than the length of the bent flange 3.

In the second step shown in FIG. 2, after this metal plate l is placed on the lower mold 4, a mandrel M is placed on this metal plate 1, and then the lower mold 4 is raised. , metal plate 1
Press it onto the mandrel M and bend it into a roughly U-shape.

In the third step shown in FIGS. 3 and 12, the upper side of the metal plate 1 bent into a U-shape is pressed from both sides of the mandrel M by regulating jigs 5, 5. This regulation jig 5
, 5 is maintained until the lock seaming is completed (until the 11th step described below).

Then, when the pair of rollers 6.6 is moved along the longitudinal direction of the mandrel M and the folding flanges 2 and 3 are overlapped by the force of the rollers 6.6, the double folding flanges 2.
The bent portions 2A and 3A of 3 contact and align on the mandrel M, and the tip side 20 of the bent flange 2 (the bent flange 2
and the non-overlapping part of the bending flange 3) is the bending flange 3
It protrudes a predetermined length from.

In the fourth step shown in FIG. 4, the tip side 20 of the bending flange 2 is held between the tapered portion 7B of one roller 7A of the roller device 7 for bending and the tapered portion 7D of the other roller 7C. When the bender roller device 7 is moved along the longitudinal direction of the mandrel M, the tip side 20 of the bending flange 2 is bent in advance at an obtuse angle.

In the fifth step shown in FIG. 5, the tip side 20 of the bending flange 2 bent at an obtuse angle is held between the lower surface 8B of the upper roller 8A of the right-angle bender roller device 8 and the upper surface 8D of the lower roller 8C. In this state, when the right-angle bender roller assembly W8 is moved along the longitudinal direction of the mandrel M, the tip side 20 of the bending flange 2 is bent at a right angle.

In the sixth step shown in FIG. 6, one roller 9A of the inverted V-shaped bender roller device 9 is pressed against the bending flange 2, and the tip side 20 of the bending flange 2 bent at right angles is pressed against the other roller 9A. When the inverted V-shaped bender roller device 9 is moved along the longitudinal direction of the mandrel M while being bent into an inverted ■ shape by the tapered portion 9C of the roller 9B,
The tip side 20 of the bending flange 2 is bent into an inverted V shape.

In the seventh step shown in FIG. 7, the folding roller device 10 is rotated while further bending the tip side 20 of the folding flange 2 bent into an inverted ■ shape by both rollers IOA and IOB of the folding roller device 10. When the mandrel M is moved along the longitudinal direction, the tip side 2 of the bending flange 2
0 overlaps the folding flange 3 and an overlapping portion 21 is formed.

In the eighth step shown in FIG. 8, the tapered portion 11B of the roller IIA of the first push-down roller device 11 and the roller IIc
When the first folding roller device 11 is moved along the longitudinal direction of the mandrel M while sandwiching the overlapping portion 21 of the bending flanges 2 and 3 between the tapered portion 11D of the bending flanges 2 and 3, the folding flanges 2 and 3 are The overlapping portion 21 is pushed down by a slight angle.

In the ninth step shown in FIG. 9, the tapered portion 12B of the roller 12A of the second folding roller device 12 and the roller 12C
When the second folding roller device 12 is moved along the longitudinal direction of the mandrel M with the overlapping part 21 of the bending flanges 2 and 3 sandwiched between the folding part 12D and the tapered part 12D of the mandrel, the folded part is pushed down by a slight angle. The overlapping portion 21 of the bending flanges 2 and 3 is pushed down at such an angle that it comes into close contact with the outer peripheral surface of the cylindrical temporary body 1 made of gold WI%.

In the tenth step shown in FIG. 10, when the third folding roller device 13 is moved along the longitudinal direction of the mandrel M, the cylindrical roller 13A of the third folding roller device 13 is moved.
The cylindrical roller 13 has a diameter larger than that of the cylindrical roller 13A.
B rotates and presses the overlapping portion 21 of the bending flanges 2 and 3, and the overlapping portion 21 of the bending flanges 2 and 3 is brought into close contact with the outer peripheral surface of the cylindrical metal plate 1.

In the 11th step shown in FIG.
When rotated and pressed by 14 cylindrical rollers 14A, the overlapping portion 21 of the bending flanges 2 and 3 is shaped and finished. In this state, when the mandrel 1 is pulled out from the cylindrical metal plate 1 and the regulating jig 5°5 clamped in the third step is released, the cylindrical muffler shell S shown in FIG. Complete.

Next, the functions and effects of this embodiment will be explained.

In the first step, the bent flanges 2 and 3 at both ends of the metal plate 1 are formed by press bending with the metal plate 1 completely unprocessed, so the double bent flanges 2, The bent portions 2A and 3A of No. 3 are formed simultaneously over the entire length, unlike the conventional example in which the side ends of a metal cylinder bent into a U-shape are bent by a roller in the middle of the process. No excessive force is applied and bending accuracy is ensured.

Therefore, in the third step, when the metal plate L is wound around the mandrel M and the double-folded flanges 2.3 are overlapped, the bent portions 2A and 3A of the double-folded flanges 2 and 3 are formed with good precision. Aligned in condition, bent part 2 of bent flange 2.3
A, 3A bending position.

The quality (average value, variation) of bending lines, etc. can be ensured. Based on this quality, for example, the folding quality of the tip side 20 of the bending flange 2 from the 4th process to the 7th process is guaranteed, and the product quality of the muffler shell S during molding in the subsequent process is guaranteed. can.

In addition, in this embodiment, a cylindrical muffler shell S
Although the description has been made for the case of manufacturing a muffler shell S, the present invention is not limited to this case, and can be applied to, for example, a case of manufacturing an oval muffler shell S, and can also be applied to parts other than the muffler shell S.

〔Effect of the invention〕

As described above, according to the method for manufacturing a metal cylindrical body according to the present invention, the bent flanges formed at the side ends of the flat metal plate are completely unprocessed. In this state, it can be bent and formed by press processing. Unlike the conventional example in which the side end of a metal cylinder that is bent into a U-shape is bent by a roller in an intermediate process, the accuracy of the bent flange can be ensured.

In addition, since the bending flange of a metal plate is simultaneously bent over its entire length by press bending, unlike the conventional example, rollers are used to bend the side edges of the metal plate along the longitudinal direction. There is no need to bend it little by little, no excessive force is applied, and the accuracy of the bending flange can be ensured.

From the above, in the process of wrapping the metal plate around the mandrel and polymerizing the bending flange, the quality (average value, variation) of the bending position 9 of the bending flange, etc. is ensured, and this quality is Based on this, it is possible to guarantee the product quality of the metal cylindrical body during molding in the subsequent process.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a metal plate in a first step of a method for manufacturing a metal cylinder according to an embodiment of the present invention. FIG. 2 is a sectional view showing a metal plate bent into a U-shape in the second step of the manufacturing method. FIG. 3 is a sectional view showing a state in which the bent flanges are polymerized in the third step of the manufacturing method. FIG. 4 is a sectional view showing a bent flange having a long flange length bent at an obtuse angle in the fourth step of the manufacturing method. FIG. 5 is a sectional view showing a bent flange having a long flange length bent at a right angle in the fifth step of the manufacturing method. FIG. 6 is a sectional view showing a bent flange having a long flange length bent in an inverted ■ shape in the sixth step of the same manufacturing method. FIG. 7 is a cross-sectional view showing a bent flange with a long flange length folded back in the seventh step of the manufacturing method. FIG. 8 is a sectional view showing the initial state in which the overlapping portions of the bending flanges are pressed down in the eighth step of the manufacturing method. FIG. 9 is a sectional view showing a state in which the overlapping portion of the bending flange is folded down in the ninth step of the manufacturing method. FIG. 10 is a sectional view showing a state in which the overlapping portions of the bending flanges have been folded down in the 10th step of the manufacturing method. FIG. 11 is a sectional view showing a state in which the shape of the overlapping portion of the folded flange is being shaped in the eleventh step of the manufacturing method. FIG. 12 is a plan view showing the method for regulating the metal plate in the third step. FIG. 13 is a cross-sectional view of a muffler shell manufactured according to an embodiment of the present invention. FIG. 14 is an explanatory diagram of a conventional method for manufacturing a metal cylinder. FIG. 15 is a detailed explanatory diagram of the second step of the conventional method for manufacturing a metal cylinder. [Description of symbols of main parts] 1... Metal plate 2. 3... Bending flange 20... Tip side 21... Overlapping portion M... Mandrel. Figure 1

Claims (1)

[Claims] (1) After forming bent flanges with different flange lengths on both ends of the cut flat metal plate by press bending, the press-bent metal plate is wound around a mandrel. , overlap the two bent flanges so that the tip side of the bent flange with the longer flange length protrudes from the bent flange with the shorter flange length, then the tip side of the bent flange with the longer flange length, A method for producing a metal cylindrical body, characterized in that the flange is folded back onto the bent flange with a shorter flange length to form an overlapping part, and the overlapping part is folded in the direction of a mandrel by lock seaming processing to form the body.