JP2974978B2 - Exhaust pipe structure of motorcycle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of an exhaust pipe mainly used for a motorcycle. More specifically, the present invention relates to a method of assembling a plurality of exhaust pipes in a stepwise manner and finally assembling two pipe sections. The present invention relates to an exhaust pipe structure of a motorcycle having a front end portion connected to a front portion of a common muffler as one pipe portion.

[0002]

2. Description of the Related Art An exhaust pipe of this kind is used for a multi-cylinder engine. For example, in a four-cylinder engine, two exhaust pipes connected to each exhaust port are assembled into two exhaust pipes. There is a four-in-one type, which is a pipe, and is further assembled into one exhaust pipe and connected to a muffler (silencer). In a two-cylinder engine, two exhaust pipes are assembled into one exhaust pipe. There is a two-in-one type connected to a muffler (silencer).

Japanese Unexamined Patent Publication No. 7-208146 discloses a four-in-one type exhaust pipe structure. As shown in FIG. And a pair of semicircular cylindrical walls 31 of a sandwich structure sandwiching the sound absorbing material 32 between a semicircular inner cylindrical wall 31b composed of a punching plate and a semi-circular inner cylindrical wall 31b. ing. FIG. 6 shows an example of a conventional exhaust pipe provided with a collecting two-pipe portion having a monaka structure. As shown in FIG.
Along the center partition plate 33, welding traces Z appear continuously on the surface in the longitudinal direction of both side surfaces. In addition, a pipe-shaped exhaust pipe 34 is connected to the distal end side of the assembled two-pipe section 30 having the monaka structure, and further a muffler (not shown) is connected. Reference numeral 35 in the drawing denotes a muffler mounting flange.

[0004]

However, the conventional exhaust pipe structure described in the above publications has room for improvement in the following points.

[0005] The assembled two-pipe portion having the monaka structure is difficult to manufacture and takes a long time to assemble, and also tends to be distorted at the time of assembling or welding.

When the cowling 36 (see FIG. 6) is mounted on the motorcycle, a part of the exhaust pipe can be covered with the cowling 36 as shown in FIG. It is difficult to cover and some parts are exposed, so the design (appearance) does not look good.

The pipe portion 34 connected to the distal end side of the two-tube portion 30 shown in FIG. 6 has a single-pipe structure, so that the surface thereof is easily discolored by the heat of the exhaust gas, and the noise such as exhaust noise is generated. Is big.

As shown in FIG. 6, a flat plate is used for the partitioning plate 33 of the collecting two-pipe portion 30, so that the joint between the pair of cylindrical walls 31 when heated by exhaust gas and extended in the width direction is formed. There is a risk of separation.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has as its object to provide a motorcycle exhaust pipe structure which is easy to manufacture, structurally stronger, and has an excellent appearance.

[0010]

In order to achieve the above object, a motorcycle exhaust pipe structure according to the present invention comprises: a) a plurality of exhaust pipes assembled in a stepwise manner, and finally an assembled two pipe section; In a motorcycle exhaust pipe structure in which the front end is connected to the front of a common muffler, b) the collective one pipe section has a double pipe structure. together constituting a pipe, c) the set double-lumen portion, a set two tube proximal portion partitioned by a partition plate in the center, specifications of the set two tube proximal portion
Extend the partition plate extension (10) from the tip of the cutting plate (6)
In the direction of the inner cylinder wall (1) around the extension (10).
1) Fitting and welding (spot welding or plug welding)
In the state of being more integrally welded, the pipe of the collecting one pipe part
Extend the base end of (8) and insert it into its extension (8a)
Of the partition plate extension (10) and the inner cylinder wall (11).
The tip is press-fit into the pipe-shaped inner wall (9) of the one-piece assembly
And an assembled two tube tip portion.

According to the exhaust pipe structure of the present invention having the above-described structure, the length of the pipe is considerably longer than that of a conventional exhaust pipe. Only the part and the muffler are exposed to the outside, and the appearance is improved. Further, the length of the collecting two pipes is substantially extended by the partition plate inserted into the pipe, and the valley of torque eliminates the torque valley in the low speed region, so that the performance particularly in the low speed region is improved. Further, since the pipe portion has a double pipe structure, discoloration does not occur on the pipe surface, and exhaust noise is reduced. Moreover, the partition plate
The distal end of the long part is fixed by welding etc. while being pressed in
The partition plate and its extension by exhaust gas.
Can extend freely in the tip direction even if the long part is heated
Therefore, the partition plate and the extension are not easily deformed.

[0012] As described in claim 2, d) the partition plate
It is preferable that (6) and the extension part (10) of the partition plate are formed so that the vertical cross section has a waveform.

According to the exhaust pipe structure of the second aspect, the partition plate expands due to the heat when the exhaust gas passes through the pipe. No adverse effect on the member.

As set forth in claim 3, e) the collecting two pipes
Is the partition of the middle part (3b)
From the tip of the plate (6), extend the partition extension (10) in the tip direction
F) punching around the extension (10)
Welding by fitting the inner cylinder wall (11) consisting of a pipe or pipe
(Spot welding or plug welding)
g) Cylindrical metal sound absorbing material made of metal fiber
Move the sound material (12) around the inner cylinder wall (11) except for the tip.
H) a pipe-like inner wall (9) of said pipe (8)
The extension (10) and the inner cylinder wall (11)
Press in the distal end, i) the proximal end of said extension (8a) and the front
The seam with the tip of the middle part (3b) is continuous in the circumferential direction
Then , it is preferable to form the structure by overlay welding (13) .

According to the exhaust pipe structure of the third aspect, it is easy to manufacture the front end portion of the two-tube assembly, and welding or the like is performed while the front end side of the partition plate extension is pressed into the base end portion of the pipe. Since the partition plate and its extension can be freely extended in the tip direction even if the partition plate and its extension are heated by the exhaust gas, the partition plate and the extension are not easily deformed.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of an exhaust pipe structure for a motorcycle according to the present invention will be described with reference to the drawings.

FIG. 1 is an overall perspective view showing an exhaust pipe 1 for a motorcycle according to an embodiment of the present invention, FIG. 2 is a central cross-sectional view showing one pipe section of the exhaust pipe 1, and FIG. FIG. 3 (b) is a cross-sectional view taken along line bb of FIG. 3 (a), and FIG. 4 is a cross-sectional view taken along line IV-IV of FIG. It shows a part of the collecting one pipe part and the collecting two pipe part,
5A is a sectional view taken along line Va-Va of FIG. 1, and FIG. 5B is a sectional view of FIG.
It is a Vb-Vb line sectional view.

As shown in FIG. 1, an exhaust pipe 1 for a motorcycle
Is a four-in-one-in type, in which four exhaust pipes 2 whose one ends are connected to respective exhaust ports (not shown) of a four-cylinder four-cycle engine are assembled into two as shown in FIG.
The two collecting pipes 3 are assembled into a single common collecting pipe 7 and connected to a large-diameter cylindrical muffler 15. The collecting two-pipe portion 3 is composed of a base end portion 3a (including an intermediate portion 3b) and a distal end portion 3c. The base end portion 3a has a gourd-shaped cross section and the intermediate portion 3b has a substantially circular cross section. Is formed. That is, the base end portion 3a and the intermediate portion 3b sandwich the heat-resistant sound-absorbing material 4c between the outer cylinder wall 4a and the inner cylinder wall 4b made of a punching plate as shown in FIG. It has a structure in which the ends are integrally butted and welded. As shown in FIG. 5 (b), the base portion 3a is an extension pipe portion of the exhaust pipe 2 (FIG. 1) to form a double inner wall partition plate 5, and the intermediate portion 3b is separate as shown in FIG. 5 (a). Is interposed between the butting portions on both sides. As the partition plate 6, a plate material whose longitudinal section is formed in a corrugated shape is used. Each exhaust pipe 2
An annular flange 2a for connection to an exhaust port (not shown) of the engine as shown in FIG. 1 and 3 indicates a welding trace at the butted portion.

The distal end portion 3c of the collecting two pipe portion 3 constitutes a characteristic portion of the present invention. As shown in FIGS. 2 and 3, the proximal end of the pipe 8 forming the outer pipe of the collecting single pipe portion 7 The outer tube of the distal end portion 3c is constituted by the side extension portion 8a. Therefore, from the appearance, as shown in FIG.
And the distal end portion 3c of the two-tube assembly 3 cannot be distinguished. As shown in FIGS. 2 and 3, the collecting pipe portion 7 has a double structure of a pipe 8 and a pipe-like inner wall 9 provided inside the pipe 8, and the pipe-like inner wall 9 is welded into the pipe 8. Then, the pipe 8 including the inner and outer walls is filled with water and is frozen and bent (so-called ice bending) to perform necessary bending. In addition, an annular flange 15a for attaching the muffler 15 is attached to the tip of the pipe 8 by welding.

As shown in FIG. 3, the leading end portion 3c extends from the leading end of the partition plate 6 of the intermediate portion 3b to the partition plate extending portion 10c.
Is extended in the distal direction, and an inner cylindrical wall 11 made of a punching plate or a pipe is fitted around the extension 10 and is integrally welded to the extension 10 by spot welding or plug welding. Further, a cylindrical metal sound absorbing material or a heat resistant sound absorbing material 12 made of metal fiber or the like is provided around the inner cylindrical wall 11 except for the end portion. Then, as shown in FIG.
To press-fit the tip portion of the pipe inner wall 9 extending portion 10 (the base end) in (inner cylindrical wall 11), a continuous seam between the tip of the proximal and intermediate portions 3b of the extension portion 8a in the circumferential direction Then, overlay welding 13 is performed. The extension portion 10 has a corrugated longitudinal section in the same manner as the partition plate 6, and only the base end side of the extension portion 10 is welded 13; Since the partition plate 6 and the extension portion 10 are not fixed to the extension portion 8a, they extend freely even if the partition plate 6 and the extension portion 10 are heated by the heat of the exhaust gas, and are unlikely to cause excessive deformation.

Finally, the muffler 15 is attached to the annular flange 15a.
Is attached. In this example, as shown in FIG. 1, the fixing bracket 17 is provided on the upper surface of the intermediate portion 3 b of the collective two-tube portion 3.
Are attached by welding. The fixing bracket 17 is fixed to a motorcycle frame and supports an intermediate portion of the exhaust pipe 1.

The exhaust pipe 1 of this embodiment is constructed as described above, and the exhaust pipe 1 is connected to the exhaust ports of the engine (not shown) of the motorcycle by the base ends of four exhaust pipes 2. ,
As shown in FIG. 1, the cylindrical muffler 15 is disposed so as to face rearward. In this state, the base end side of the exhaust pipe 1 is covered with the cowling 16, and the distal end portion 3 c of the cylindrical muffler 15, the collecting one pipe part 7 and the collecting two pipe part 3 are exposed from the cowling 16.

Therefore, since the outer tube is formed by the common pipe 8 at the tip portion 3c of the collecting single pipe portion 7 and the collecting double pipe portion 3, the appearance is smart and beautiful because welding marks are not visible. In addition, the base portion 3a and the intermediate portion 3 of the collecting two-tube portion 3
b has a monaka structure as in the prior art, but is very short as shown in FIG. Moreover, there is no inconvenience because the cowling 16 completely hides the outer appearance. Further, since the collecting single pipe portion 7 and the collecting double pipe portion 3 have a double pipe structure over the entire length, exhaust noise is reduced, and discoloration occurs even when high-temperature exhaust gas passes through the surface of the pipe 8 or the like. The appearance is kept beautiful for a long time.

Although one embodiment of the present invention has been described above, the present invention can be implemented as follows.

Applicable to a two-in-one type in which two exhaust pipes are assembled and a muffler is connected to the gathering part, or when six exhaust pipes are finally assembled into one and a muffler is connected to the gathering part. it can.

Basically, a ready-made pipe 8 having the same diameter is used, but a pipe whose diameter gradually increases rearward may be used.

In the collecting pipe section 7, a sound absorbing material is interposed in the gap between the pipe 8 and the pipe-shaped inner wall 9, so that the exhaust sound leaking to the outside can be further reduced. in this case,
It is desirable to use a metal sound absorbing material so that ice bending can be performed.

[0028]

As is apparent from the above description,
The exhaust pipe structure for a motorcycle according to the present invention has the following excellent effects.

(1) Since the length of the pipe is considerably longer than that of the conventional exhaust pipe, in the case of a motorcycle with a cowling, only the pipe and the muffler can be exposed to the outside. , The appearance is improved. In addition, the partition plate inserted into the pipe substantially increases the length of the assembled two-pipe portion, so that the performance particularly in a low-speed region is improved. Furthermore, since the pipe part has a double pipe structure,
No scorching occurs on the pipe surface, and exhaust noise is reduced.
In addition, since an off-the-shelf pipe can be used, it is easy to manufacture, structurally strong, and durable. Moreover,
Do not weld the distal end of the
The partition plate is not fixed by the exhaust gas.
And its extension can freely extend in the direction of the tip even when heated.
The partition plate and the extension portion are not easily deformed.

(2) In the exhaust pipe structure according to the second aspect, the partition plate and the extension portion expand (elongate) due to heat generated when the exhaust gas passes through the pipe. Does not adversely affect other members or separate joints.

(3) In the exhaust pipe structure according to the third aspect, it is easy to manufacture the front end portion of the combined two pipes, and welding or the like is performed while the front end side of the partition plate extension is pressed into the base end portion of the pipe. Since the partition plate and its extension can be freely extended in the distal direction even if the partition plate and its extension are heated by the exhaust gas, the partition plate and the extension do not undergo excessive deformation.

[Brief description of the drawings]

FIG. 1 is an exhaust pipe 1 for a motorcycle according to an embodiment of the present invention.
FIG.

FIG. 2 is a central cross-sectional view showing a single pipe portion of the exhaust pipe 1 of FIG.

FIG. 3 (a) is a central cross-sectional view showing a tip portion of a combined two pipes of an exhaust pipe 1, and FIG. 3 (b) is a cross-sectional view taken along line bb of FIG. 3 (a).

FIG. 4 is a sectional view taken along the line IV-IV of FIG. 1 and shows a part of a collecting one pipe part and a collecting two pipe part of the exhaust pipe 1;

5 (a) is a sectional view taken along line Va-Va of FIG. 1, and FIG. 5 (b)
FIG. 2 is a sectional view taken along line Vb-Vb in FIG. 1.

FIG. 6 is a perspective view showing a part of a conventional motorcycle exhaust pipe provided with a two-tube assembly having a Monaka structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Exhaust pipe 2 Exhaust pipe 3 Collecting two pipe part 3a Base end part of collecting two pipe part 3 3b Intermediate part of collecting two pipe part 3 3c Tip part of collecting two pipe part 3 5.6 Partition plate 7 Collecting one pipe part 8 Pipe 8a Extension part at base end side of pipe 8 9 Pipe-shaped inner wall 10 Partition plate extension part 11 Inner cylinder wall 12 Sound absorbing material 16 Cowling

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F01N 1/10 F01N 7/08

Claims (3)

(57) [Claims] 1. A plurality of exhaust pipes are gathered in a stepwise manner, and finally two gathering pipes are gathered to form a gathering one pipe part, and a tip end thereof is connected to a front part of a common muffler. In the exhaust pipe structure of a motorcycle, the collective one pipe portion is formed of a pipe having a double pipe structure, and the collective two pipe portion is divided by a central partition plate into a collective two pipe base end portion, The partition plate (6) at the proximal end of this
Extend the partition extension (10) from the tip in the tip direction,
An inner cylindrical wall (11) is fitted around the extension (10) to melt it.
In the state of being welded together by welding, the pie
Extend the proximal end of the loop (8) and insert it into its extension (8a).
Insert and extend the partition plate extension (10) and inner cylinder wall (11)
Is pressed into the pipe-shaped inner wall (9) of the collecting pipe.
Exhaust structure of a motorcycle, characterized in that consisted the off to set two-tube distal end portion. 2. An exhaust pipe structure for a motorcycle according to claim 1, wherein said partition plate (6) and said partition plate extension (10) are formed so as to have a vertical section in a waveform. 3. A tip portion (3c) of the collecting two pipes is
From the tip of the partition plate (6) in the middle part (3b)
The plate extension (10) is extended in the distal direction, and the extension (1) is extended.
Inside of a punching plate or pipe around 0)
The cylindrical wall (11) is fitted and welded together by welding,
Cylindrical metal sound-absorbing material or heat-resistant sound-absorbing material made of fiber, etc.
(12) around the inner cylinder wall (11) except for the tip part
The base end of the pipe-shaped inner wall (9) of the pipe (8)
Extension part (10) and tip of inner cylinder wall (11) inside
And press-fit the base portion of the extension portion (8a) and the intermediate portion.
The seam with the tip of minute (3b) is continuously built up in the circumferential direction.
The exhaust pipe structure for a motorcycle according to claim 1 or 2, wherein the exhaust pipe structure is welded (13) .