JPS62244539A - Manufacture of exhaust pipe - Google Patents

Abstract

PURPOSE:To simplify a welding and to prevent the reduction in an endurance strength by processing one sheet of a metal slab material via the punching stage of an equal leg trapezoid, sectional U shape drawing stage, sectional O-shaped wind bending stage and welding integration stage. CONSTITUTION:The punching piece 15 corresponding to the development contour shape of an exhaust pipe is subjected to a punching from a metal slab material. A half bending piece 18 is made by drawing in a sectional U shape so as to bend from the center line (Y-Y) of the punching piece 15. Thereafter, a wind bending is performed by a pair of symmetrical bending dies 19, 20 by setting the core 21 of a conical pipe shape by inserting it into the U-shaped groove of the half-bent piece 18. Since the wind bending pipe 23 is provided with the butt ridge part 24 running in the longitudinal direction, an exhaust pipe A is completed by integrating the ridge part 24 with its welding. Consequently the welding spots are reduced and the product having excellent endurance strength and quality for the use can be subjected to a mass production.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Field of Application> The present invention relates to a method of manufacturing, by press working, an exhaust pipe for an engine mounted on an automobile, motorcycle, or other vehicle.

<Conventional technology and its problems> For example, in the exhaust pipe of an engine installed in a motorcycle, the exhaust inlet on the side connected to the exhaust manifold has a diameter that is gradually smaller than the exhaust outlet on the opposite side. The overall shape of the conical tube is small, and the part of the chamber that collects the exhaust gas is generally curved into an elbow shape. As is clear from Figures 34 and 35, in manufacturing, the press-worked separate half bodies ta) have their outwardly projecting flange portions (b) in a state of folding their hands together like a so-called middle confectionery. They are joined and fixedly integrated by welding.

Therefore, there are many places that require welding, which makes the work extremely complicated and increases costs.In addition, if there is even the slightest defect in the welding, it may cause problems during use. Repeatedly exposed to the high heat and pressure of exhaust gas,
It easily becomes distorted and deformed, resulting in a significant decrease in durability and strength, and also has the problem of impairing the uniformity and appearance of the product.

<Means for Solving the Problems> The present invention is a method for manufacturing an exhaust pipe intended to solve the above problems, in which a metal flat plate material is basically equally produced using a pair of male and female punching dies. The first process No. 6 involves punching out a punched piece in the form of a trapezoid, and the second process involves drawing it into a U-shaped cross section using a pair of male and female drawing dies, as if bending the core wire in half; While inserting and removably inserting a core with a circular cross section into the letter-shaped groove, the half-bent pieces are bent using a pair of symmetrical bending dies facing each other to form an exhaust inlet section along the longitudinal direction of the target exhaust pipe. However, the third part is also bent into a 0-shaped cross section with a diameter smaller than that of the exhaust outlet part.
The first feature is that it consists of a fourth step of welding the butted ridgeline portions of the rolled pipes formed in the third step, and a fourth step of welding together the butted ridgeline portions of the rolled pipes formed in the third step. The first step is to punch out a punched piece that basically forms an isosceles trapezoid using a die;
A second step of drawing into a U-shaped cross section; while inserting and removably inserting and setting a 7-shaped core with a circular cross section into the U-shaped groove; 7. Only the exhaust inlet portions along the longitudinal direction of the exhaust pipes are joined so as to be partitioned into a three-pronged branch shape, and at the same time, one of the branched exhaust inlet portions is rolled up into a 0-shaped cross section.
Step; The other exhaust inlet section branched in the third step and the exhaust outlet section along the longitudinal direction of the exhaust pipe each have a U-shaped cross section and communicate with each other. While inserting and setting a pair of straight cores in a removable manner,
The pair of bending dies, which are also symmetrical, ensure that the other exhaust inlet has substantially the same diameter as the one exhaust inlet that is bent first, and has a diameter that is smaller than the R exhaust outlet. a fourth step of simultaneously bending the other exhaust inlet portion and the exhaust outlet portion to form a zero-shaped cross section with a smaller cross section; The second feature is that it consists of a fifth step in which the parts are then welded together.

<First embodiment> Hereinafter, the present invention will be described in detail based on the drawings.
Figure 10 shows the manufacturing process of the first embodiment and the processing conditions in each process. (A) is the exhaust pipe to be obtained, but due to its use, it is not connected to the exhaust manifold side of the engine. The aperture size (old) of the connected exhaust inlet part (11) is the opposite aperture size (r1) of the exhaust outlet part (12).
2) It has a smaller overall conical tube shape. The exhaust outlet portion (12) is connected to a muffler (not shown).

In manufacturing the above exhaust pipe (A), first, in the first step shown in FIG.
A pair of male and female punching dies (13) and lower dies (14) are used to punch out a piece (15) in the form of an isosceles trapezoid. The basic isosceles trapezoid of the obtained punched piece (15) corresponds to the developed contour shape of the intended exhaust pipe (A), and as is clear from FIG. It has a center line of symmetry (Y-Y).

Next, in the second step shown in FIGS. 3 to 5, the punched piece (15) is cut by the center line of symmetry indicated by I- ( Y
-Y) is bent in half, so to speak, and drawn into a "1-shaped" cross section to form a half-bent piece (18) as shown in FIG. In that case, the 18th exhaust pipe (A) is the target exhaust pipe (A).
In order to obtain a curved elbow shape as shown in the figure, the mating shaping surfaces of the pair of male and female drawing upper molds (16) and lower molds (17) are adjusted as shown in FIGS. 11 to 13. By bending it into an arc along the center line of symmetry (Y-Y) when viewed from the lateral direction, the back of the half-bent piece (18) is drawn at the same time when it is drawn into the U-shaped cross section. Also the first
It is curved as shown in Figure 4.

Thereafter, in the third step shown in FIGS. 7 to 9, the half-bent piece (18) is bent by a pair of opposing symmetrical upper molds (19) and lower molds (20) to form the exhaust gas. The exhaust inlet part (11) of the pipe (A) is also formed into a zero-shaped cross section with a diameter smaller than that of the exhaust outlet part (12). )
is inserted into the U-shaped groove of the half-bent piece (18).By bending the fitting surface of the half-bent piece (18) into an arc shape as shown in Figs. 15 to 17, the above-mentioned elbow-shaped exhaust It is also possible to obtain a tube, but in that case, in order to allow the core (21) to be smoothly inserted and removed into the groove of the half-bent piece (18) and to be able to fit stably, it is necessary to The child (21) is divided in advance into a plurality of pieces as shown in Fig. 16.19, and adjacent pieces of the divided bodies are connected by connecting pieces (2
2), etc., it is preferable to make a refractably pivotal connection.

The rolled pipe (
23) has a butt ridge line (24) running in the longitudinal direction as shown in FIG. A) is completed. If the target exhaust pipe (A') has an elbow shape, the abutting ridge line (24) will extend into the abdomen, as suggested from FIG. 18.

Therefore, according to the configuration of the above embodiment, the welding is purified, and since the exhaust pipe (A) is pressed from a single metal flat plate material, the exhaust pipe (A) is not affected by high heat or high pressure of the exhaust when used. Its durable strength and quality are not affected by 4J,
This means that products with excellent aesthetics can be mass-produced at low cost.

<Second Example> Next, FIGS. 20 to 33 show the manufacturing process according to the second example of the present invention and the processing state in each process.
The target exhaust pipe (B) is the exhaust inlet part (11a)
(11b) is bifurcated into a left and right pair.

However, the diameter size (11l) of each exhaust part (11a) (11b) is the same as the diameter size (11l) of the exhaust outlet part (12).
D2) is the same as the first embodiment described above in that it is set smaller than D2).

In manufacturing the exhaust pipe (B) as described above, the metal flat plate material (M) is first manufactured in the same way as the first step of the first embodiment.
A punched piece (15) is obtained by subjecting it to a pair of male and female punching dies (13) and 2 (14) and punching it into a basic isosceles trapezoid. Next, in a second step similar to the first example, the punched pieces (15
) as shown in Figures 20 to 22.
6) and the lower die (17), bend the punched piece (15) in half from the center line of symmetry (Y-Y).
It is drawn into a U-shaped cross section as shown in the figure.

Then, in the third step shown in FIGS. 24 to 27, the half-bent piece (18) thus obtained is inserted into a Y-shaped core (25) having a circular cross section into the groove having a U-shaped cross section. While setting, a pair of symmetrical upper bending molds (19a
) and the lower die (20a), the bending process is performed by bending only the exhaust inlet part (11a) (1lb) of the exhaust pipe (B), which is the above-mentioned objective, into a three-pronged branch that is parallel to each other as a left and right pair. In order to partition the molds (19a) (20a
), and at the same time, one of the branched exhaust inlet portions (11a) is formed into a 0-shaped cross section.

In that case, the core (25) is partially inserted and set into and removably into the recess (S) formed in the lower mold (20a), as suggested from Fig. 26.27. 1
3. Moreover, it is always elastically pressed in the upward direction by a spring material (26) that has been filled with silk in advance into the lower mold (20a). Then, a presser rod (correspondingly protruding from the upper die (19a) so as to face the spring material (26))
27), the core (25) has two half-white pieces (1
8), press the upper mold (19a) in the lower mold (20a) with the presser rod (27), ! :
It is designed to be stably pressed down and tightly adhered to the mating forming surface of. After completing the winding and bending process, the core (25
) is pulled out from the recess (S) of the lower mold (20a), and the core (25) is left in a U-shaped cross section from one exhaust inlet part (11a) which is rolled up with a O-shaped cross section. The other exhaust inlet section (11b) and exhaust outlet section (12)
After that, the tit is removed from the processed piece without any trouble.

Next, as shown in the fourth step of FIGS. 29 to 32, -! the other exhaust inlet part (11b) branched into a two-part trifurcated shape;
A straight core (28) with a circular cross section is inserted into the groove that forms a U-shaped cross section and communicates with the remaining exhaust outlet part (12).
The pair of (29) are removably inserted and set by the teeth 149b) and the lower mold (20b), and the other exhaust inlet part (11b) and exhaust outlet part (12),! : are rolled up and bent at the same time, and both are formed into a 0-shaped cross section as shown in Figure 33.

In that case, the aperture size (old) of the other exhaust inlet (11b) is changed from one exhaust inlet (1
It is set to be substantially the same as that in 1a), and smaller than the aperture size (D2) of the exhaust outlet part (12). The above pair of cores (28) and (29) are designed to facilitate the insertion of the workpiece in the previous process, and also to form a fit with the upper mold (1!'lb) in the lower mold (20b). In order to ensure stable contact with the surface, it is desirable that at least one of the cores (29) is pivotally supported on the lower mold (20b) so as to be freely rotatable in an undulating manner. (30) shows the pivot pin.

The three-pronged bent tube (23) formed through the above step 3.4 has a butted configuration at the ridgeline portion (24) extending along its longitudinal direction, as shown in Fig. 33. Therefore, the final step is to add one additional layer to the exhaust pipe (B) for the above purpose. With the configuration of this second embodiment as well, it is possible to efficiently mass-produce products with excellent quality and strength.

<Effects of the Invention> As described above, in the method for manufacturing an exhaust pipe according to the present invention, a metal flat plate material (M) is cut into a pair of 11ff vertebrae punching molds (13).
A first step of punching out a punched piece (15) basically forming an isosceles trapezoid according to (14): A center line of symmetry (Y-Y) along the longitudinal direction of the punched piece (15)
The second step is to draw the core into a U-shaped cross section using a pair of male and female drawing dies (16) and (17), as if bending it in half; While (21) is inserted and set in a removable manner, the half-bent piece (18) is formed into a desired exhaust pipe (A) using a pair of symmetrical bending dies (19) and (20) facing each other.
a third step of bending the exhaust inlet portion (11) along the longitudinal direction into a 0-shaped cross section with a diameter smaller than that of the exhaust outlet portion (12); Butt ridge line part (24) of bent pipe (23)
), and then a fourth process of welding them together, it is possible to completely solve the problems of the conventional technology mentioned at the beginning, and it has the effect of being able to mass-produce excellent products at low cost. be.

In addition to the above step 1.2, a groove with a circular cross section of 7 is inserted into the U-shaped cross-section groove of the half-bent piece (18) thus formed.
While the character-shaped core (25) is inserted and set in a removable manner, the half-bent piece (18) is cut into the desired exhaust pipe (B
) Exhaust inlet part (11a) (11b) along the longitudinal direction
At the same time, one of the branched exhaust inlets (11a) is joined to form a three-pronged branched section.
a third step of bending into a letter shape; the other exhaust inlet portion (11b) and the exhaust outlet portion (12), which are branched in the third step, each have a U-shaped cross section and communicate with each other in the groove; To, straight cores with circular cross sections (28) (29
) are inserted and set in a removable manner, and the other exhaust inlet part (11b) is bent first by a pair of symmetrical bending molds (19b) (201kl17b). It has substantially the same aperture size as the exhaust inlet part (r11a), and has two exhaust inlet parts (12
), the other exhaust inlet part (11b) and the exhaust outlet part (12) are simultaneously rolled up to form a zero-shaped cross section, and then the fifth step is performed. Even if the process is configured to perform welding corresponding to the third process described above, the above-mentioned effects can be similarly exhibited, and it can be said that the invention is highly practical.

[Brief explanation of drawings]

1 to 19 show a first embodiment of the present invention, in which FIG. 1 is a sectional view showing the punching operation in the first step, and FIG.
The figure is a perspective view of the punched piece, FIG. 3 is a cross-sectional view showing the mold opening state of the drawing action related to the second step, and FIG. 4 is 4-4 in FIG.
4-line cross-sectional view, Figure 5 is a cross-sectional view of the mold closed state, and Figure 6 is a cross-sectional view of the mold in the closed state.
The figure is a perspective view of the half-bent piece, Figure 7 is a cross-sectional view showing the mold opening state during the winding action in the third step, Figure 8 is a cross-sectional view of Figure 7, and Figure 10 is the rolled tube. Slope view, No. 11~
FIG. 18 is a sectional view and a slope view of a partial modification corresponding to FIGS. 3 to 10, of which FIG.
12, and FIG. 16 shows cross-sectional views taken along line 16--16 of FIG. 15, respectively. Fig. 19 is a perspective view of the core extracted, Figs. 20 to 33 show a second embodiment of the present invention, and Fig. 20 is a sectional view showing the mold opening state of the drawing action related to the second step. , Figure 21 is 21-2 in Figure 20.
1 line sectional view, Fig. 22 is a sectional view of the same mold closed state, Fig. 23 is a perspective view of the half-bent piece, and Figs. 24 and 25 are 3rd sectional views.
26 is a cross-sectional view taken along the line 26-26 in FIG. 25, FIG. 27 is a cross-sectional view taken along the line 27-27 in FIG. 26, 28th
The figure is an oblique view of the processed piece, Figure 29 is a sectional view showing the mold opening state during the winding action in the fourth step, and Figure 30 is the second
30-30 line sectional view in Figure 9, Figure 31 is 31 in Figure 30.
-31 line cross-sectional view, Figure 32 is also a closed state of Danyo 1
94 is a side view showing a conventional exhaust pipe, and FIG. 35 is a sectional view taken along line 35-35 in FIG. 34. (A) (B) ・・・・・・・・・Exhaust pipe (M)
・・・・・・・・・・・・Flat plate material (13) (1
4) ・・・・・・・・・・・・Punching mold (15)・・・
・・・・・・・・・Punching pieces (16) (17)
・・・・・・・・・Drawing die (18)・・・
...... Half-bent piece (19) (20) (1
9a) (20a) (19b) (20b) ・Bending mold (21) (25) (28) (29) ・
・・・・・・Nakako (23)・・・・・・・・・・・・・・・
Winding pipe (24)......Butt ridge line portion (11) (11a) (11b)...
...Exhaust inlet (12) ...Exhaust outlet (Y-Y) ...... Center line of symmetry (P) ...・・・・・・・・・Joint location (
1) l) (112) .........Aperture dimensions Patent applicant Hashida Giken Kogyo Co., Ltd.;゛, 1 horn Figure 1 Figure 2 Figure 5 Figure 6 Figure 7 Figure 9 Figure 8 Figure 10 A 23 Figure 11 Figure 13 Figure 12 Figure 15 = Figure 17 Figure 16 Motion factor → Figure 21 Figure η Figure 23 Figure Field

Claims (1)

[Claims] 1. A metal flat plate material (M) is cut into a pair of male and female punching dies (13
) (14), the first step is punching out a punched piece (15) basically forming an isosceles trapezoid, and the punched piece (15) is cut along the center line of symmetry (Y
The second step is drawing into a U-shaped cross section using a pair of male and female drawing dies (16 and 17), as if bending it in half from -Y). While the core (21) is inserted and set in a removable manner, the half-bent piece (18) is cut into the longitudinal direction of the target exhaust pipe (A) using a pair of symmetrical bending dies (19) and (20) facing each other. A third step in which the exhaust inlet portion (11) along the direction is bent into an O-shaped cross section in which the diameter is also smaller than the exhaust outlet portion (12), and the bent pipe formed by the third step. The butt ridge line part (24) of (23) is then welded into a fourth
A manufacturing method of an exhaust pipe, which consists of a process. 2. The punched piece (15) is drawn into a U-shaped cross section, and the half-bent piece (18) is then rolled up and bent into an O-shaped cross section. Type (16)
By (17), the cross-sectional shape is U-shaped, and at the same time,
The center line of symmetry (Y-Y) along the longitudinal direction is drawn into an elbow shape when viewed from the lateral direction, and the half-bent piece (18) is rolled up into an O-shaped cross section. 2. The method of manufacturing an exhaust pipe according to claim 1, wherein the member (21) has an elbow shape that is curved as a whole and can be divided into a plurality of pieces. 3. Cut the metal plate material (M) into a pair of male and female molds (13)
(14), a punched piece that basically forms an isosceles trapezoid (
15), and the punched piece (15) is cut along the center line of symmetry (Y-
The second step is to draw a U-shaped cross section using a pair of male and female drawing dies (16 and 17), as if bending it in half from Y). Y-shaped core (2
5) while inserting and removably inserting and setting the half-bent piece (1).
8) into a pair of symmetrical bending dies (19a) (2) facing each other.
0a), only the exhaust inlet parts (11a) (11b) along the longitudinal direction of the target exhaust pipe (B) are joined so as to be partitioned into a bifurcated shape, and at the same time, one of the branched exhaust inlet parts (11a) into an O-shaped cross section, the other exhaust inlet (11b) branched by the third step, and the exhaust outlet of the exhaust pipe (B) also along the longitudinal direction. A pair of straight cores (28) and (29), each having a circular cross section, are removably inserted into the grooves communicating with the portion (12), each having a U-shaped cross section. A pair of bending dies (19b) (20
b), the other exhaust inlet part (11b) has substantially the same diameter as the previously bent one exhaust inlet part (11a), and has a larger diameter than the exhaust outlet part (12). A fourth step of simultaneously bending the other exhaust inlet portion (11b) and exhaust outlet portion (12) into an O-shaped cross section with a smaller diameter, and a fork formed by the fourth step. Branched winding pipe (
23) A method for manufacturing an exhaust pipe comprising a fifth step of welding the abutted ridge line portions (24) together.