JPH06554A - Structure for joined part in metallic cylindrical body and manufacture of metallic cylindrical body - Google Patents

Abstract

PURPOSE:To provide a manufacturing method by which a joined part structure improving air tightness at the joining part of a metallic cylindrical body with simple structure, and a metallic cylindrical body can easily be manufactured. CONSTITUTION:In the metallic cylindrical body joining both bent flanges 17a, 17b by overlapping the bent flanges 17a, 17b formed at both side ends of the metallic sheet 17 wound to a mandrel and bending the overlapping parts of both bent flanges 17a, 17b to the mandrel direction according to lock seaming, the one side of the bent flanges 17a, 17b is formed as the wave shape, i.e., preceding to the lock seaming, the one side of the bent flanges 17a, 17b in the metallic sheet 17 is formed as the wave shape.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for joining a metallic cylinder such as a shell constituting a vehicle muffler and a method for manufacturing the metallic cylinder.

[0002]

2. Description of the Related Art Generally, a metal cylinder made of a metal thin plate is disclosed in Japanese Patent Laid-Open No. 61-195722 by bending a plate-shaped metal thin plate into a cylinder and welding its side end. It is joined by a lock seaming process.

FIG. 19 shows the steps of the lock seaming process disclosed in the above publication. First, in the first step (I),
After placing the metal thin plate 3 on the lower mold 1, and placing the mandrel 5 on the metal thin plate 3, the lower mold 1 is raised and the metal thin plate 3 is pressed against the mandrel 5 to move it. It is bent in a U shape.

Then, in the second step (II), as shown in FIG. 20, one end of the metal thin plate 3 is provided with a pair of T-shaped rollers 7.
Is bent into a substantially L shape to form a bent flange 3a, and the other end is bent into a substantially V shape by a pair of abacus bead rollers 9 to form a bent flange 3b.

Next, in the third step (III), as shown in FIG. 21, both end sides of the metal thin plate 3 bent in a U shape are pressed against the mandrel 5 by the spatula 11 to make the metal thin plate 3
Regulate.

Then, in the fourth step (IV), one bending flange 3a is pressed against the inside of the other bending flange 3b by a pair of rollers (not shown) to be polymerized, and then the bending flange 3b tip is bent. The part 3b 'is bent on the other bending flange 3a and the process proceeds to the fifth step (V). Then, the metal cylindrical body 13 is obtained by lock seaming the overlapping portions of both the bent flanges 3a and 3b. Note that FIG. 22 is an enlarged front view of the joint portion 3c of the two bent flanges 3a and 3b that are lock seamed.

[0007]

However, in the metal cylinder 13 as described above, the airtightness is difficult due to the spring back of the bent flanges 3a and 3b in the joint portion 3c. When the metal cylinder 13 is used as a shell for a vehicle muffler, there is a risk that exhaust gas may leak from the joint 3c.

Further, in order to improve the airtightness of the joint portion 3c, conventionally, for example, a liquid curing agent is applied to the inner surface of the bending flange 3b or a string-like sealing member is incorporated, so that both bending flanges 3a, Although methods such as lock seaming of 3b have also been adopted, the actual situation is that these methods are troublesome.

The present invention has been devised in view of the above circumstances, and is directed to a metal cylinder body in which the airtightness of a joint portion of a metal cylinder body such as a shell constituting a vehicle muffler is improved by a simple structure. It is an object of the present invention to provide a joint structure and a method for manufacturing a metal cylinder body that can easily manufacture such a metal cylinder body.

[0010]

In order to achieve such an object, the structure of the joint portion of the metal cylinder body according to the invention of claim 1 is
A metal cylinder in which bent flanges formed on both ends of a thin metal plate wrapped around a mandrel are overlapped, and the overlapped parts of both bent flanges are bent and formed in the mandrel direction according to lock seaming, and both bent flanges are joined. In the body, one of the bent flanges is formed in a wavy shape.

In the method for manufacturing a metal cylinder according to the present invention, a step of winding a flat metal thin plate around a mandrel and bending flanges having different flange lengths at both ends of the metal thin plate. A step of forming a metal thin plate from both sides in the mandrel direction with a pressing die, a step of superposing one of the bending flanges on the other bending flange, and a overlapping portion of the bending flange according to lock seaming. In a method of manufacturing a metal cylinder body, which comprises bending and forming in the mandrel direction and joining both bending flanges, one of the bending flanges of the metal thin plate is corrugated prior to lock seaming. It is characterized by being molded.

[0012]

According to the joint structure of the metal cylinder of the first aspect, since one of the bending flanges is formed in a wavy shape, the bending flange after lock seaming has the other bending flange due to its residual stress. The airtightness of the joint is ensured by pressure contact with several points on the inner surface of the.

Further, according to the method of manufacturing a metal cylinder according to the second aspect, one of the bent flanges of the metal thin plate is formed into a wavy shape before the lock seaming, so that the lock seaming is performed after the folding. Due to the residual stress of the bent flange, the metal tubular body in which the bent flange is pressed against several places on the inner surface of the other bent flange to ensure the airtightness of the joint portion can be easily manufactured.

[0014]

Embodiments of the present invention will now be described in detail with reference to the drawings. In FIG. 1, reference numeral 15 denotes a metal tubular body according to an embodiment of the present invention. The metal tubular body 15 is made of a metal thin plate 17 as in the conventional case.
Bending flanges 17a and 17b formed on both side ends of the two are overlapped, and the overlapped portions are bent and formed in the mandrel direction according to lock seaming to form the two folding flanges 17a and 1b.
7b is joined.

FIG. 2 is an enlarged front view of the joint portion 17c of the bent flanges 17a and 17b which are lock-seamed. As is clear from this figure, the bent flange 17 is shown.
The bending flange 17a sandwiched by b is formed in a wavy shape, and the bending flange 17a has three places on the inner surface of the bending flange 17b (in the figure, due to its residual stress).
A, B, C) are pressed against each other to ensure the airtightness of the joint 17c.

The metal cylinder 15 according to this embodiment is constructed in this manner, and the metal cylinder 15 is manufactured by one embodiment of the method of the present invention described below. As shown in FIG. 3, as in the conventional case, first, in the first step, the lower mold 19
After the metal thin plate 17 is placed on the mandrel 21, the mandrel 21 is placed on the metal thin plate 17, and then the lower mold 19 is lifted to press the metal thin plate 17 against the mandrel 21 to form a U-shape. Fold it in.

Then, in the second step shown in FIG. 4, the pair of rollers 23 and 25 are arranged in parallel with the mandrel 21, that is,
While running in the longitudinal direction of the mandrel 21, each roller 2
Both side ends of the metal thin plate 17 are bent outward by the tapered portions 23a and 25a of the bending flanges 17a and 1a, respectively.
7b is formed.

The bent flange 17b is the bent flange 1.
The rollers 23 and 25 are set to be longer than 7a. However, as in the conventional case, both rollers 23 and 25 are configured to rotate when they come into contact with the metal thin plate 17 by being driven by the moving device. There is.

Next, in a third step shown in FIG. 5, a pair of corrugating rollers (not shown) are run in the longitudinal direction of the mandrel 21 to form one bent flange 17a into a wavy shape, and then, as shown in FIG. Proceeding to the fourth step, the upper side of the metal thin plate 17 bent into a U-shape is pressed toward the mandrel 21 from both sides of the mandrel 21 by four pressing dies (sparers) 27 as shown in FIG. Incidentally, as in the conventional case, the pressing by these pressing dies (spas) 27 is continued until the lock seaming is completed.

The pair of rollers 29 are connected to the mandrel 2
When the vehicle is run in the longitudinal direction of 1, the bending flange 17b projects from the bending flange 17a by a predetermined length, and
As described above, the two bent flanges 17a and 17b are superposed on the roller 29.

Next, in a fifth step shown in FIG. 8, the taper portion 3 of one roller 31a of the prepender roller device 31 is used.
The tip side of the bent flange 17b is sandwiched between 1a 'and the tapered portion 31b' of the other roller 31b. Then, in this state, the prepender roller device 31 is attached to the mandrel 21.
And the tip of the bending flange 17b is bent at an obtuse angle in advance.

Thereafter, in the sixth step shown in FIG. 9, the lower surface 33 of the upper roller 33a of the roller device 33 for right-angle bender.
By holding the tip of the bent flange 17b bent at an obtuse angle between a'and the upper surface 33b 'of the lower roller 33b, the roller device 33 for a right-angle bender is run in the longitudinal direction of the mandrel 21 and bent. The tip of the flange 17b is bent at a right angle.

After the sixth step is completed, the process shown in FIG.
In the seventh step 0 shown in FIG.
One roller 35a is pressed against the bending flange 17b, and the tip of the bending flange 17b bent at a right angle is bent in an inverted V shape by the taper portion 35b 'of the other roller 35b. The vendor roller device 35 is run in the longitudinal direction of the mandrel 21.

Then, in the eighth step shown in FIG. 11, the tip end of the bent flange 17b bent in an inverted V shape is further bent by both rollers 37a and 37b of the return roller 37, and the return roller 37 is formed. When the mandrel 21 travels in the longitudinal direction, the tip of the bent flange 17b overlaps the bent flange 17a.

Next, in the ninth step shown in FIG.
Tapered portion 39 of roller 39a of folding roller device 39
After the overlapping portion of both the bending flanges 17a and 17b is sandwiched between a'and the taper portion 39b 'of the other roller 39b, the first bending roller device 39 is caused to run in the longitudinal direction of the mandrel 21 to overlap. Fold the entire part at a slight angle.

After this, the process proceeds to the tenth step shown in FIG. 13, and the taper portion 41a 'of the roller 41a of the second folding roller device 41 and the taper portion 41b' of the other roller 41b are carried out.
When the second bending roller device 41 is made to travel in the longitudinal direction of the mandrel 21 with the overlapping portions of the two bending flanges 17a and 17b sandwiched between them, the entire overlapping portion is formed of a cylindrical metal thin plate 17 It will be bent to the extent that it is in close contact with the outer peripheral surface of the.

Then, in the eleventh step of FIG. 14, when the third bending roller device 43 is run in the longitudinal direction of the mandrel 21, the cylindrical roller 4 of the third bending roller device 43 is moved.
3a and a cylindrical roller 4 having a diameter larger than that of the cylindrical roller 43a.
3b rotates and presses on the overlapping portions of the bent flanges 17a and 17b, and the overlapping portions have a cylindrical thin metal plate 17
Will be in close contact with the outer peripheral surface of.

Then, as shown in FIG. 14, the last first
In the two steps, when the roller 45a of the shaping roller device 45 is rotated and pressed onto the overlapping portion of both the bent flanges 17a and 17b, the overlapping portion is shaped and finished as shown in FIG. Since 17c is molded, in this state, the mandrel 2 is cut from the cylindrical thin metal plate 17
When 1 is pulled out and the four pressing dies 27 clamped in the fourth step are released, the cylindrical metal tubular body 15 is completed as shown in FIG.

Thus, the metal cylinder 15 formed in this way
A muffler for a vehicle can be obtained by, for example, incorporating a baffle plate into which a muffler tube is inserted and then closing the openings at both ends of the metal tubular body 15 with end plates.

As described above, the metal cylinder 1 according to this embodiment
5 is a bent flange 1 of the bent flanges 17a and 17b formed on the side end of the metal thin plate 17 as shown in FIG.
Since the bent flange 17a sandwiched by 7b is formed in a corrugated shape prior to the lock seaming, according to the present embodiment, the bent flange 17a has three places on the inner surface of the bent flange 17b due to the residual stress after the lock seaming. (A, B, C in the figure) is pressed to secure the airtightness of the joint 17c.

Therefore, when the metal cylinder 15 according to the present embodiment is used as a shell of a vehicle muffler, for example,
Compared with the conventional structure shown in FIG. 22, the airtightness of the joint 17c is dramatically improved, and it is no longer necessary to incorporate a troublesome seal member as in the conventional case.

Further, according to the method of manufacturing the metal cylinder 15 of this embodiment, in addition to the conventional manufacturing process of the metal cylinder,
Since it suffices to add a step of forming the bent flange 17a in a corrugated shape with a pair of corrugating rollers, there is an advantage that the metal cylindrical body 15 having the above effect can be easily manufactured.

In the above embodiment, one of the bent flanges 17a is formed into a wavy shape with a pair of corrugation rollers.
As shown in FIG. 17, the tip end side of the other bending flange 17b is formed into a wavy shape, and the bending flange 17b is formed at four positions on the inner surface of the bending flange 17a by the residual stress of the bending flange 17b (in the figure, (D, E, F, G) may be pressed against each other to ensure the hermeticity of the joint 17c.

In the above embodiment, the metal thin plate 17 is placed on the lower mold 19 and the bending flanges 17a and 17b are formed by the rollers 23 and 25, and then the bending flange 17a is further formed into a pair of corrugations. Although the metal thin plate 17 was formed into a wavy shape by using a roller, as shown in FIG. 18, both side ends of the metal thin plate 17 were pressed to form a wavy bent flange 17a before the metal thin plate 17 was placed on the lower die 19. It is also possible to form the bent flange 17b and the metal thin plate 17 on the lower mold 19 and form the metal cylinder in the same process as the conventional one.

Thus, even with such a manufacturing method, the intended purpose can be achieved as in the case of the above-mentioned method of the present invention, and further, the step of lock seaming is performed in the above-mentioned embodiment. It is not limited to.

[0036]

As described above, according to the joining portion structure of the metal tubular body according to the present invention, the airtightness of the joining portion is dramatically improved as compared with the conventional one, and the labor required in the conventional one is increased. It is no longer necessary to install such a seal member.

Further, according to the method for manufacturing a metal cylinder according to the present invention, in addition to the conventional manufacturing process for a metal cylinder, it is only necessary to add a step of forming one bent flange into a wavy shape. Therefore, there is an advantage that the metal cylinder body having the above effect can be easily manufactured.

[Brief description of drawings]

FIG. 1 is a perspective view of a metal cylinder body according to the present invention.

FIG. 2 is an enlarged front view of a joint portion of a bent flange of the metal cylinder body shown in FIG.

FIG. 3 is a cross-sectional view showing a first step of an embodiment of the method for manufacturing a metal tubular body according to the present invention.

FIG. 4 is a sectional view showing a second step of the embodiment of the manufacturing method.

FIG. 5 is a sectional view showing a third step of the embodiment of the manufacturing method.

FIG. 6 is a cross-sectional view showing a fourth step of the embodiment of the manufacturing method.

FIG. 7 is a plan view of a fourth step shown in FIG.

FIG. 8 is a sectional view showing a fifth step of the embodiment of the manufacturing method.

FIG. 9 is a sectional view showing a sixth step of the embodiment of the manufacturing method.

FIG. 10 is a cross-sectional view showing a seventh step of the example of the manufacturing method.

FIG. 11 is a cross-sectional view showing an eighth step of the example of the manufacturing method.

FIG. 12 is a cross-sectional view showing a ninth step of the example of the manufacturing method.

FIG. 13 is a sectional view showing a tenth step of the example of the manufacturing method.

FIG. 14 is a sectional view showing an eleventh step of the embodiment of the manufacturing method.

FIG. 15 is a sectional view showing a twelfth step of the embodiment of the manufacturing method.

FIG. 16 is a cross-sectional view of a metal cylinder body formed by the manufacturing method.

FIG. 17 is an enlarged front view of a joint portion showing a modified example of the joint portion structure according to the present invention.

FIG. 18 is a side view of a metal thin plate showing another step of the manufacturing method according to the present invention.

FIG. 19 is a schematic view showing a conventional method for manufacturing a metal tubular body.

FIG. 20 is an explanatory diagram of one step of a conventional method for manufacturing a metal tubular body.

FIG. 21 is an explanatory diagram of one step of a conventional method for manufacturing a metal tubular body.

FIG. 22 is an enlarged front view of a joint portion of a conventional metal cylinder body.

[Explanation of symbols]

 15 Metal Cylindrical Body 17 Metallic Thin Plate 17a, 17b Bending Flange 17c Joint 19 Lower Mold 21 Mandrel

Claims (2)

[Claims] 1. A bent flange (17) formed at both ends of a thin metal plate (17) wound around a mandrel (21).
a, 17b) are overlapped, and both bent flanges (17a, 17b)
The overlapped portion of b) is bent and formed in the direction of the mandrel (21) according to lock seaming to form a double bent flange (17).
a, 17b), a metal cylinder body, wherein one of the bent flanges (17a, 17b) is formed in a wavy shape. 2. A step of winding a flat metal thin plate (17) around a mandrel (21), and the metal thin plate (1).
7) Bending flanges (1
7a, 17b) and a thin metal plate (17)
Mandrels (21) from both sides by pressing die (27)
Direction and the bending flange (17a, 17a
b) a step of superposing one side on the other bent flange (17a, 17b), and the overlapping portion of the bent flange (17a, 17b) is subjected to lock seaming according to the mandrel (2
1) Bend in both directions to form both bent flanges (17a,
17b) joining step, and a method of manufacturing a metal tubular body comprising the steps of: forming one of the bent flanges (17a, 17b) of the metal thin plate (17) into a wavy shape prior to lock seaming. A method for manufacturing a metal cylinder body, comprising: