JP3504607B2 - Exhaust system component, outer cylinder of exhaust system component, and method of manufacturing the outer cylinder - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust system component, an outer cylinder of the exhaust system component, and a method of manufacturing the outer cylinder.

[0002]

2. Description of the Related Art Conventionally, there are a main muffler and a sub muffler as exhaust system parts of an internal combustion engine mounted on an automobile. Since this sub-muffler has a relatively small capacity with respect to the main muffler, the outer cylinder of the sub-muffler generally has a main body 101 made of a metal cylinder having a circular cross-sectional shape, as shown in FIG.
A neck portion 102 formed by reducing the diameter of the main body portion 101 into a circular shape having a diameter smaller than that of the main body portion 101 at both end portions;
In many cases, a taper-shaped reduced-diameter portion 103 for connecting the neck portion 102 and the neck portion 102 is integrally formed.

However, it is difficult to mount such a sub-muffler having a circular main body 101 when the space under the vehicle floor is small.

Therefore, the main body 101 of the outer cylinder of the sub-muffler having the circular cross-sectional shape is pressure-molded in the radial direction so that the cross-sectional shape of the main body 201 is non-circular (for example, elliptical) as shown in FIG. ) To reduce the thickness in one direction by plastic deformation, it is also adopted that can be installed in a small space under the vehicle floor.

The pressure molding of the outer cylinder in such a non-circular sub-muffler will be described with reference to FIG.

The mold used for pressure molding is an upper mold 301 and a lower mold 3.
02 and the main body 10
1, body forming surfaces 303 and 304 corresponding to No. 1, neck forming surfaces 305 and 306 corresponding to the neck 102, and gradually changing forming surfaces 307 and 308 corresponding to the reduced diameter portion 103 are formed. Further, as shown in FIG.
When 1 comes into contact with the lower mold 302, the cross-sectional shape formed by the body molding surfaces 303, 304 becomes elliptical as shown in FIG. 26, and the neck molding surfaces 305, 306 are formed.
27 becomes circular as shown in FIG. 27, and the cross-sectional shape formed by the both gradually changing molding surfaces 307 and 308 is an elliptical neck molding on the body molding surfaces 303 and 304 side. The surfaces 305 and 306 are formed in a circular shape with a gradually changing shape between them.

The outer cylinder of the sub-muffler having the circular cross-sectional shape is an upper mold 30 as shown in FIG. 25 (a).
1 and the lower mold 302, the upper mold 301 is lowered by a press machine, and as shown in FIG. 25B, the main body 101 of the outer cylinder is brought into contact with the main body molding surface 303 of the upper mold 301. Contact is made and pressure molding is started. Further, when the upper die 301 is lowered, the main body molding surface 3 of the upper die 301 and the lower die 302
03, 304 push the upper and lower surfaces of the main body 101,
As shown in FIG. 25C, when the upper die 301 comes into contact with the lower die 302, the main body 101 is formed into an elliptical shape along the elliptical molding surface formed by both the main body molding surfaces 303 and 304. To be done. Further, following the pressure molding, the reduced diameter portion 103 is also gradually deformed along the mold surfaces of both the gradually changing molding surfaces 307 and 308, and the cross-sectional shape as shown in FIG. An outer cylinder having a circular main body portion 201, a non-circular reduced diameter portion 202, and a circular neck portion 203 is obtained.

In such an outer cylinder having a non-circular cross-sectional shape, when the outer cylinder is molded into an elliptical shape as described above, the peripheral length of the ellipse after molding (see FIG. 24 (b)). Circumference)
Is approximately the same as the perimeter before the elliptical molding (perimeter in FIG. 23 (b)) to prevent deformation of the outer cylinder in the circumferential direction, especially buckling due to excess perimeter. .

[0009]

By the way, in order to meet the demand for improvement of quietness by the muffler, it is necessary to increase the capacity of the sub muffler. If such an increase is made, the vehicle mountability deteriorates. In order not to do so, it is necessary to further increase the amount of deformation due to the pressure molding.

However, in the conventional non-circular pressure molding method, although the circumferential length of the outer cylinder in the circumferential direction is taken into consideration as described above, the axial length of the reduced diameter portion 103 is taken into consideration. Since the excess or deficiency is not taken into account, if the volume of the sub-muffler is increased and the amount of pressurization is increased as described above, the pressurization as shown in FIG. As shown in FIG. 24 (a), the axial length L ₂ of the reduced diameter portion 202 after pressure molding becomes shorter than the axial length L ₁ of the reduced diameter portion 103 before molding, and the reduced diameter portion 202
Excess material in the axial direction at. Therefore, since the surface rigidity is higher on the reduced diameter portion 202 side than on the main body portion 201,
Buckling occurred in the main body 201 having low surface rigidity, and a sub-muffler with a large amount of pressure molding could not be obtained.

Therefore, the present invention is intended to prevent the occurrence of buckling in the main body as described above.

[0012]

In order to solve the above-mentioned problems, a first invention according to claim 1 is a cylindrical shape having a circular cross section.
At least one end of the body of the
A tubular neck having a circular cross section, the main body and the neck.
The reduced diameter part to be connected is integrally molded, and the main body is
Apply pressure to make the cross-sectional shape of the body and the reduced diameter part non-circular.
An exhaust system part having a molded outer cylinder,
The distance from the center of the reduced diameter portion of the cylinder to the reduced diameter portion is added.
Axial direction of the reduced diameter part in the part that becomes shorter after pressure forming
The recess is shaped so that the length of the
It is an exhaust system component characterized by being made.

[0013]

[0014]

[0015] The second invention of claim 2, in at least one end portion of the tubular body portion of circular cross a small-diameter cross-sectional circular cylindrical neck portion from the body portion, the said body portion An outer cylinder of an exhaust system component, which is obtained by radially pressing an outer cylinder integrally formed with a reduced diameter portion connecting a neck portion, and forming a cross-sectional shape of the main body portion and the reduced diameter portion into a non-circular shape. In the portion where the distance from the center of the reduced diameter portion to the reduced diameter portion is shortened after pressure molding, a recess is formed so that the axial length of the reduced diameter portion is substantially equal before and after pressure molding. It is an outer cylinder of an exhaust system component characterized in that

[0016] A third invention of claim 3, wherein, in at least one end portion of the tubular body portion of circular cross a small-diameter cross-sectional circular cylindrical neck portion from the body portion, the said body portion A method for manufacturing an outer cylinder of an exhaust system component, wherein an outer cylinder integrally formed with a reduced diameter portion that connects a neck portion is pressed in a radial direction to form a cross-sectional shape of the main body portion and the reduced diameter portion into a non-circular shape. And a step of pressurizing a part of the reduced diameter portion to form a concave portion, and, after starting the formation of the concave portion, pressurizing the main body portion in the radial direction to make the cross-sectional shape of the main body portion non-circular. The method for manufacturing an outer cylinder of an exhaust system component, comprising:

[0017] A fourth invention of claim 4, wherein, in the third invention, the recess, in the center distance to the reduced diameter portion is shortened after pressure molding from a portion of the reduced diameter portion, a condensed This is a method for manufacturing an outer cylinder of an exhaust system component, in which the axial length of the diameter portion is formed to be substantially equal before and after pressure molding.

[0018] The fifth invention of claim 5, wherein, in the third addition <br/> 4 of the invention, after gripping the outer circumferential surface of the neck portion, the pressing of the molding and the body portion of the recess This is a method of manufacturing an outer cylinder of an exhaust system component.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described based on the embodiments shown in FIGS. 1 to 22 in which the present invention is applied to a sub-muffler which is an exhaust system component of an internal combustion engine.

FIG. 1 shows the constituent material of the manufactured sub-muffler. Reference numeral 1 is a metal cylindrical body which is an outer cylinder, into which an inner pipe 3 having a large number of small holes 2 is inserted. A sound absorbing material 4 is interposed between the inner pipe 3 and the outer cylinder 1.

FIG. 2 shows a sub-muffler (intermediate material) having an outer cylinder 5 formed by reducing the diameter of both ends of the cylindrical body by spinning. The outer cylinder 5 of the sub-muffler 6 is a cylindrical shape having a diameter smaller than that of the main body 5a and having a circular cross-sectional shape by subjecting both ends of the main body 5a formed of the cylindrical body 1 to a diameter reduction process by a spinning roller 7. Neck portions 5b and 5c, and reduced diameter portions 5d that connect the neck portions 5b and 5c to the main body portion 5a,
5e and 5e are integrally formed on both ends of the main body 5a. The neck portions 5b and 5c are formed to have a diameter that makes close contact with the outer peripheral surface of the inner pipe 3 or contacts an inclusion (not shown) wound around the outer peripheral surface of the inner pipe 3. Further, the reduced diameter portions 5d and 5e are formed in a conical taper shape whose diameter is concentric in the axial direction and whose diameter changes.

Next, the process of press-molding the sub-muffler 6 which is an intermediate material formed as described above into a sub-muffler having a non-circular cross section will be described with reference to FIGS. 3 to 9.

The press-molding die is composed of an upper die 8 and a lower die 9, and the upper die 8 is centered at a boundary position between the neck portions 5b, 5c of the outer cylinder 5 and the reduced diameter portions 5d, 5e in the sub-muffler 6. The upper die 8a and the upper neck die 8b, 8c are divided into three parts.

Similarly, the lower die 9 also has a neck portion 5b of the outer cylinder 5,
At the boundary position between 5c and the reduced diameter portions 5d and 5e, a lower center mold 9a and two lower neck molds 9b and 9c are divided into three parts.

As shown in FIG. 8, when the central upper die 8a and the central lower die 9a are brought into contact with each other,
Main body mold cavities 8d, 9d having an elliptical cross section are formed at the main body 5a of the outer cylinder 5 of the sub muffler 6. The perimeter of the elliptical shape formed by the body portion mold holes 8d and 9d is the same as the body portion 5a of the outer cylinder 5 shown in FIG.
Is set to be approximately equal to the circular circumference.

The upper neck mold 8b, 8c and the lower neck mold 9b,
As shown in FIG. 9, the neck portions 5b, 5 of the outer cylinder 5 of the sub-muffler 6 are attached to the sub-muffler 6 as shown in FIG.
Neck mold holes 8e, 9 positioned at c and having a circular cross section
e and 8f and 9f are formed. This neck mold hole 8
The diameters of the holes formed by e, 9e and 8f, 9f are the same as those in FIG.
The diameter is set to be equal to the outer diameter of the neck portions 5b and 5c shown in FIG.

Further, the central upper die 8a and the central lower die 9a have reduced diameter portions 5d, 5 of the outer cylinder 5 of the sub-muffler 6, respectively.
The taper-shaped holes 8g, 9g and 8h, 9h gradually changing from the main body mold holes 8d, 9d shown in FIG. 8 to the neck mold holes 8f, 9f (8e, 9e) shown in FIG. Has been done. Further, the tapered holes 8g, 9g and 8h, 9h have reduced diameter portions 5d, 5 of the outer cylinder 5 of the sub-muffler 6, respectively.
Projections 8i and 9i for forming a recess are formed in e.
The shapes of the protrusions 8i and 9i will be described later.

The central upper die 8a is fixed to the upper die base 10 of the press working machine, and the central lower die 9a is fixed to the lower die base 11 of the press working machine. The neck upper mold 8
The bolts 12 are fixedly mounted on the lower molds b, 8c and the neck lower molds 9b, 9c.
The upper neck molds 8b and 8c and the lower neck mold 9 are slidably inserted into the upper and lower neck molds 9 by the biasing means 13 composed of a coil spring.
b and 9c are urged toward each other, the neck upper molds 8b and 8c and the neck lower molds 9b and 9c project inward as shown in FIG. When a load from the inside to the outside is applied to the lower neck molds 9b and 9c, the upper neck molds 8b and 8c and the lower neck molds 9b and 9c resist the biasing force of the biasing means 13 in the outward direction. It is designed to move.

Next, a method of manufacturing the outer cylinder of the sub-muffler having a non-circular cross section by pressurizing the outer cylinder 5 of the sub-muffler 6 shown in FIG. 2 using the above mold will be described.

First, as shown in FIG. 3, when the upper die base 10 is in the raised position, and the central upper die 8a and both neck upper dies 8b and 8c are in the raised position, the upper die base 10 shown in FIG. The sub-muffler 6 shown in FIG.
b and 5c are placed on the lower neck molds 9b and 9c and placed in the mold.

Next, the upper die base 10 is moved downward by a press machine (not shown) to move the central upper die 8a and both neck upper die 8 to each other.
When b and 8c are lowered, as shown in FIG. 4, before the central upper die 8a comes into contact with the outer cylinder 5 of the sub-muffler 6, that is, before the pressure molding of the main body 5a and both the reduced diameter portions 5d and 5e. Both neck upper molds 8b, 8c abut the necks 5b, 5c of the outer cylinder 5 and the urging force of the urging means 13 causes the necks 5b, 5c.
c is gripped in a pressure contact state by the upper and lower neck mold holes 8e, 9e and 8f, 9f. In this gripped state, the neck upper mold 8b,
8c and the lower neck molds 9b, 9c abut on the abutment surface S outside the die cavity as shown in FIG. In this way both necks 5b, 5c
When the outer cylinder 5 is pressed in the next step, the axial movement of the outer cylinder 5 is regulated and the main body portion 5a and the reduced diameter portions 5d and 5e of the outer cylinder 5 are gripped by gripping. The neck portions 5b and 5c are not affected by the pressure forming.

Incidentally, in the conventional mold shown in FIG. 25, when the main body 101 and the reduced diameter portion 103 are pressure-molded, both necks 102 are in a free state, so the main body 10
Although the neck portion 102 is deformed under the influence of the pressure molding of No. 1, before the pressure molding of the main body portion 5a and the reduced diameter portions 5d and 5e in the next step as in the embodiment of the present invention. Upper neck mold 8b, 8c and lower neck mold 9b, 9c
By previously grasping b and 5c, the above-mentioned conventional problems can be solved.

Further, when the upper die base 10 is moved downward from the state shown in FIG. 4, the upper neck dies 8b, 8c and the lower neck die 9b,
The upper die 8 and the lower neck dies 9b and 9c are slightly lowered in a state in which the neck 9c grips both necks 5b and 5c of the outer cylinder 5, and the outer cylinder 5 is slightly lowered as shown in FIG. At the same time as 5d and 5e abut on the protruding die 9i of the central lower die 9a, the protruding die 8i of the central upper die 8a abuts on the reduced diameter portions 5d and 5e of the outer cylinder 5, and at the reduced diameter portions 5d and 5e. Molding of the concave portion is started.

Further, when the upper mold base 10 is moved downward, FIG.
As shown in FIG. 3, the central upper mold 8a is further lowered, and the protruding mold 8i formed on the central upper mold 8a and the protruding mold 9i formed on the central lower mold 9a move the reduced diameter portions 5d and 5e of the outer cylinder 5 to each other. The recess 14 is formed in the reduced diameter portions 5d and 5e by applying pressure. Further, the uppermost surface of the main body mold cavity 8d of the central upper mold 8a is the main body 5a of the outer cylinder 5.
9d of the central lower die 9a
Of the outer cylinder 5 abuts on the lowest surface of the main body 5a of the outer cylinder 5. Even when the upper die base 10 is lowered, the neck upper die 8b,
8c and the lower neck dies 9b, 9c descend while holding both necks 5b, 5c, and the main body 5a of the outer cylinder 5 and both necks 5b, 5c.
Keep the axis of c the same.

Further, when the upper die base 10 moves downward, FIG.
As shown in FIG. 7, the main body part mold hole 8d of the central part upper mold 8a and the main body part mold hole 9d of the central part lower mold 9a are the main body part 5a of the outer cylinder 5.
Is pressed inward in the radial direction so that the main body portion 5a becomes a non-circular main body portion 5a ', and in the illustrated embodiment, the main body portion mold hole 8 shown in FIG.
An elliptical shape is formed along the ellipse formed by d and 9d. In addition, the protruding mold 8 in the reduced diameter portions 5d and 5e
Parts other than the recessed part 14 formed by i and 9i are formed in a shape along the tapered mold holes 8g and 9g.

The pressure molding is completed as described above, and the main body 5
A sub-muffler 6A having an outer cylinder 5A in which a'and the reduced diameter portions 5d ', 5e' have a non-circular cross-sectional shape is formed. Then, the upper die base 10 is moved upward to take out the molded non-circular sub muffler 6A from the die.

FIGS. 10 to 12 show a sub-muffler 6A having an outer cylinder 5A whose cross-sectional shape is non-circular by the above pressure molding. In FIGS. 10 and 12, the hatched portion (range) is the concave portion 14 formed by the pressure molding.

Next, the recess 14 will be described in detail.

In FIG. 13 (a), the two-dot chain line shows the cross-sectional shape of the main body 5a of the outer cylinder 5 before pressure molding,
The solid line shows the cross-sectional shape of the non-circular main body 5a 'after pressure molding. In this figure, the distance from the center of the outer cylinder 5 (the center of the main body portion 5) to the main body portion 5a before pressure molding is X.
And the non-circular main body 5 from the center of the outer cylinder 5 after pressure molding.
Assuming that the distance to a'is Y, the range indicated by Z in FIG. 13A is shorter at the distance Y than at the distance X.

Further, due to the deformation of the main body portion 5a due to the pressurization, the portions of the reduced diameter portions 5d and 5e on the main body portion 5a side are also deformed as shown in FIG. 13 (b). This Figure 1
In 3 (b), the two-dot chain line indicates the reduced diameter portion 5 before pressure molding.
The cross-sectional shapes of d and 5e are shown, and the solid line shows the cross-sectional shape of the non-circular reduced-diameter portions 5d 'and 5e' after pressure molding.
In this figure, the distance from the center of the outer cylinder 5 (the center of the diameter-reduced portion) to the diameter-reduced portions 5d and 5e before the pressure molding is X ', and the center of the outer cylinder 5 after the pressure molding has a non-circular shape. Reduced diameter portion 5d ', 5
Assuming that the distance to e'is Y ', the range indicated by Z'in FIG. 13B is shorter at the distance Y'than at the distance X'. Therefore, the axial length of the reduced diameter portions 5d 'and 5e' in the range Z ', when the concave portion 14 is not formed, is
Due to the pressurization, the length becomes shorter than the axial length L ₁ shown in FIG. 2, the surface rigidity of the portion becomes high, and there is a problem that the main body portion is buckled as in the conventional case.

Therefore, the concave portion 14 has a reduced diameter portion 5
It is desirable to provide it at a position corresponding to the range of Z'in d'and 5e '.

Further, the reduced diameter portions 5d ', 5e' after pressure molding
Axial length L passing through the recess 14 in ₂(See Figure 11)
Is the axial length L of the reduced diameter portions 5d and 5e before pressure molding
₁Set the recess 14 so as to be substantially the same as (see FIG. 2).
Is desirable.

The circumferential lengths of the reduced diameter portions 5d and 5e after the pressure molding shown in FIGS. 10 and 11 are substantially equal to the circumferential lengths of the reduced diameter portions 5d and 5e before the pressure molding. It is desirable to set

FIG. 14 shows a second embodiment of the present invention.

In the second embodiment, when the non-circular pressure-molding in the above-mentioned embodiment is performed, the main body portion 5a and the main body portion 5a are compressed by using a mold for pressure-forming the main body portion and the reduced diameter portion into a substantially triangular shape. Diameter part 5
The outer cylinder 5B having a substantially triangular cross-sectional shape of d and 5e is formed under pressure. This substantially triangular body is 5a ',
The substantially triangular reduced diameter portions are shown as 5d 'and 5e'. Neck 5
The cross-sectional shape of b and 5c is circular as described above. Further, in this embodiment, the recess 14 similar to the above is formed on the three sides forming the reduced diameter portions 5b 'and 5c'.
The shape of the recess 14 is formed so as to exhibit the same operation and effect as those of the above-described embodiment.

16 to 22 show a third embodiment of the present invention. The third embodiment is an example in which the present invention is applied to an outer cylinder in which the neck portions 5b and 5c and the reduced diameter portions 5d and 5e are eccentric or inclined with respect to the central axis of the main body portion 5a.

In this embodiment, a metal cylindrical body 1 which serves as an outer cylinder as shown in FIG. 16 is used. First, as shown in FIG. 17, one end side of the main body portion 5a composed of the cylindrical body 1 is used. Is reduced in diameter such that its axis X ₂ is inclined at a predetermined angle θ with respect to the central axis X ₁ of the main body 5a to form a cylindrical neck 5b, and between the neck 5b and the main body 5a. The reduced diameter portion 5d is formed. Further, the other end of the main body portion 5a, with its shaft center X ₃ to form a cylindrical neck portion 5c reduced in diameter in a state in which a predetermined amount OF eccentric with respect to the central axis X ₁ of the main body portion 5a An outer cylinder (intermediate material) 5 is obtained by forming a reduced diameter portion 5e between the neck portion 5c and the main body portion 5a. The method for forming the slanted neck portion 5b and the reduced diameter portion 5d and the method for forming the eccentric neck portion 5c and the reduced diameter portion 5e are described in, for example, Patent No. 2
A molding method using spinning as described in Japanese Patent No. 957153 and Japanese Patent No. 2957154 can be adopted.

Next, the outer cylinder 5 is pressed in the radial direction (the direction perpendicular to the paper surface in FIG. 17) by the same upper and lower molds as those shown in FIGS. 3 to 9 in the same manner as described above. In addition,
The upper and lower molds are matched with the neck and the reduced diameter part which are inclined and eccentric as described above. Further, the upper and lower molds are formed with the protruding molds 8i and 9i similar to the above.

As a result of this pressure molding, as shown in FIGS. 20 to 22, a cylinder tilted with respect to the central axis X ₁ of the main body 5a 'on one end side of the main body 5a' having an elliptical cross section. -Shaped neck portion 5b and reduced diameter portion 5d 'are integrally formed, and
'At the other end of the main body portion 5a' main body portion 5a outer cylinder 5C which cylindrical neck portion 5c and the reduced diameter portion 5e which is eccentric with respect to the central axis X ₁ of the 'are integrally formed is obtained.

Simultaneously with the pressure molding, the protruding molds 8i, 9i formed on the central upper mold 8a and the central lower mold 9a.
As a result, recesses 14 similar to those of the first embodiment are formed in the reduced diameter portions 5d 'and 5e'. In this third embodiment as well, by forming the recess 14, the same action and effect as in the first embodiment can be exhibited.

Although the third embodiment has been described with respect to the molding of only the outer cylinder, the third embodiment is also applicable to the outer cylinder in which the inner pipe shown in the first embodiment is inserted and the catalyst carrier and the like are housed. Can be applied.

Further, when the eccentric neck portion 5c and the reduced diameter portion 5e 'shown in the third embodiment are formed on both ends of the main body portion 5a', or the inclined neck portion 5b and the reduced diameter portion 5d 'are formed in the main body. The present invention can be applied to the case of forming both ends of the portion 5a '.

Further, according to the present invention, as in the first to third embodiments, the main body portion and the reduced diameter portion of the outer cylinder are pressure-molded so that their cross-sectional shapes are elliptical or substantially triangular. Outside the case,
The present invention can be applied to the case where the cross-sectional shape of the main body portion and the reduced diameter portion of the outer cylinder is pressure-formed into an arbitrary non-circular shape such as an oval or a rectangle. Furthermore, in each of the above-mentioned embodiments, when the outer cylinder is pressure-molded, an elastic body or a liquid is put inside the outer cylinder,
By these, the outer cylinder may be pressure-molded while the inner pressure is applied to the outer cylinder.

Further, each of the above embodiments is an example in which the present invention is applied to a sub-muffler, but the present invention can be applied to a silencer other than the sub-muffler. Furthermore, not only the silencer but also a catalytic converter or a diesel particulate filter. It can also be applied to the outer cylinder of an exhaust manifold, etc., and can be applied to all outer cylinders of exhaust system parts.

Further, each of the above embodiments is an application example in which the reduced diameter portion and the neck portion are formed at both ends of the main body portion, but the reduced diameter portion and the neck portion are formed only at one end portion of the main body portion. The present invention can also be applied in such cases.

[0056]

As described above, according to the present invention, when the recessed portion is formed in the reduced diameter portion of the outer cylinder, the main body portion having a circular cross-sectional shape is press-formed into a non-circular shape. Since the change in the axial length of the reduced diameter portion that occurs is adjusted by the recess, the exhaust system component having a large non-circular cross section with a large amount of pressure molding can be formed without causing buckling in the main body unlike the conventional case. An outer cylinder and an exhaust system component having this outer cylinder can be obtained.
Therefore, the vehicle mountability of the exhaust system component can be improved.

According to the third and fourth aspects of the invention, the outer cylinder exhibiting the above-mentioned effects and the exhaust system component having the outer cylinder can be easily formed.

According to the fifth aspect of the present invention, it is possible to suppress the deformation of the neck portion due to the pressure molding of the main body portion of the outer cylinder.

[Brief description of drawings]

1A and 1B show constituent materials in an embodiment in which the present invention is applied to a sub-muffler, wherein FIG. 1A is a side sectional view and FIG. 1B is a sectional view taken along the line AA in FIG.

FIG. 2 is a side sectional view in which both ends of the outer cylinder in FIG. 1 are reduced in diameter.

FIG. 3 is a side cross-sectional view showing a first embodiment in which the sub-muffler shown in FIG. 2 is pressure-molded and in which the sub-muffler shown in FIG. 2 is arranged in a pressure molding die.

FIG. 4 is a side cross-sectional view of the state in which the upper die is lowered from the state of FIG. 3 to hold the neck portion of the sub muffler.

5 is a side sectional view showing a state in which the upper die is further lowered from the state of FIG. 4 to bring the protruding die into contact with the sub muffler.

6 is a side cross-sectional view showing a state where the upper die is further lowered from the state of FIG. 5 to form a concave portion by a protruding die.

FIG. 7 is a side cross-sectional view in which the upper die is further lowered from the state of FIG. 6 and the main body of the outer cylinder is pressure-molded.

8 is a cross-sectional view taken along the line BB in FIG. 7, in which the sub muffler is excluded.

9 is an end view of the mold in FIG. 7, with the submuffler omitted.

FIG. 10 is a plan view of a sub-muffler formed by the steps of FIGS.

11 is a side sectional view of FIG.

FIG. 12 is a diagram viewed from the direction of arrow C in FIG.

13 (a) and 13 (b) are views for explaining the formation position of the recess in the present invention.

FIG. 14 is a side view showing the outer cylinder of the second embodiment of the present invention.

FIG. 15 is a view seen from the direction of arrow D in FIG.

FIG. 16 is a side sectional view showing a constituent material of an outer cylinder according to a third embodiment of the present invention.

FIG. 17 is a plan sectional view in which both ends of the outer cylinder of FIG. 16 are reduced in diameter.

18 is a cross-sectional view taken along the line EE in FIG.

19 is a sectional view taken along line FF in FIG.

20 is a plan view showing an outer cylinder in which the outer cylinder shown in FIG. 17 is pressed to have a non-circular shape. FIG.

FIG. 21 is a view seen from the direction G in FIG. 20.

22 is a diagram viewed from the H direction in FIG. 20.

23A and 23B show a conventional outer cylinder, in which FIG. 23A is a side view before pressure molding, and FIG. 23B is a sectional view taken along line I-I in FIG.

FIG. 24 is a view showing a state where the outer cylinder of FIG. 23 is pressure-molded into a non-circular shape, (a) is a side view, and (b) is a sectional view taken along the line JJ in (a).

25 (a) to (c) show the outer cylinder shown in FIG.
Sectional drawing which shows the type | mold and the process which pressure-mold in the shape shown in FIG.

FIG. 26 is a sectional view taken along line KK in FIG.

27 is an end view of FIG. 25 (c).

[Explanation of symbols]

5,5A, 5B, 5C Outer cylinder 5a, 5a 'main body 5b, 5c neck 5d, 5e, 5d ', 5e' Reduced diameter part 8 Upper mold 9 Lower mold 8i, 9i protruding type 14 recess

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Jiro Kagaya 5-5 Hachidayama, Miyoshi, Miyoshi-cho, Nishikamo-gun, Aichi 35 Sango Hachiwadayama Co., Ltd. (72) Inventor Masayuki Yokoi Nishikamo-gun, Aichi Miyoshi-cho large character Miyoshi character 5-5 Hawadayama 35 Sango Hawadayama Co., Ltd. (56) Reference JP-A-7-310520 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB) Name) F01N 1/00 F01N 1/02 F01N 1/04 F01N 7/18

Claims (5)

(57) [Claims] 1. A tubular neck portion having a circular cross section having a diameter smaller than that of the body portion, and a reduced diameter portion connecting the body portion and the neck portion to at least one end portion of the tubular body portion having a circular cross section. Is integrally molded, and the main body portion is pressed in the radial direction, and an exhaust system component having an outer cylinder in which the cross-sectional shape of the main body portion and the reduced diameter portion is formed into a non-circular shape, In the portion where the distance from the center of the diameter portion to the reduced diameter portion is shortened after pressure molding, a recess is formed so that the axial length of the reduced diameter portion is substantially equal before and after pressure molding. Exhaust system parts characterized by 2. A tubular neck portion having a circular cross section having a diameter smaller than that of the body portion, and a reduced diameter portion connecting the body portion and the neck portion to at least one end portion of the tubular body portion having a circular cross section. Is an outer cylinder of an exhaust system component in which a cross-sectional shape of the main body portion and the reduced diameter portion is formed into a non-circular shape by radially pressing the outer cylinder integrally molded from the center of the reduced diameter portion. Exhaust, characterized in that in the portion where the distance to the reduced diameter portion becomes shorter after pressure molding, a recess is formed such that the axial length of the reduced diameter portion is substantially equal before and after pressure molding. Outer cylinder for system parts. 3. A tubular neck portion having a circular cross section and having a diameter smaller than that of the body portion, and a reduced diameter portion connecting the body portion and the neck portion to at least one end portion of the tubular body portion having a circular cross section. A method for manufacturing an outer cylinder of an exhaust system component, wherein the outer cylinder integrally molded with is radially pressed to form a cross-sectional shape of the main body portion and the reduced diameter portion into a non-circular shape, A step of pressurizing a part thereof to form a concave portion, and a step of pressing the main body portion in a radial direction after forming the concave portion to form a cross-sectional shape of the main body portion into a non-circular shape. A method of manufacturing an outer cylinder of a characteristic exhaust system component. 4. The portion of the recess where the distance from the center of the reduced diameter portion to the reduced diameter portion is shortened after pressure molding, and the axial length of the reduced diameter portion is substantially before and after pressure molding. The method for manufacturing an outer cylinder of an exhaust system component according to claim 3, wherein the outer cylinders are formed to have the same shape. After gripping the 5. outer peripheral surface of the neck portion, the production method of the outer cylinder of the exhaust system component according to claim 3 or 4, wherein performing the pressing of the molding and the body portion of the recess.