JPH11324668A - Structure of gathering part of exhaust pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a fastened part advantageous in strength and to secure the control of a foreign sound by providing many small holes on a mating face of an exhaust pipe on one upstream side, and severally providing a notched part in a part opposite to many small holes on a mating face of an exhaust pipe on other upstream side. SOLUTION: Each of downstream parts of upstream side exhaust pipes 1,2 is semicircularly formed in a section to form each of mating faces 1a, 2a. The downstream end of the mating face 2a of the upstream side exhaust pipe 2 on one side is provided with an about semicircular notch part 5. A part opposite to the notch 5 of the mating face 1a is provided with a plurality of small holes 4. Both the mating faces 1a, 2a are matched with each other, and the downstream ends of two upstream side exhaust pipes are insertingly fitted in a downstream side exhaust pipe 3, and they are firmly connected. Thus since the upstream side exhaust pipes are mutually fixed in a face-contact state, stress does not concentrate in the fixed part, which is advantageous in strength. In addition, the positional alignment of the small holes on both the mating faces is unnecessary, and since the small hole is never shut, a foreign sound can be certainly controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in the structure of an exhaust pipe assembly, for example, when a dual exhaust pipe is connected to a single exhaust pipe.

[0002]

2. Description of the Related Art As an assembly structure of an exhaust pipe, a fitting surface is formed at a downstream end portion of a plurality of upstream exhaust pipes, and the fitting faces are aligned and inserted into and fixed to a downstream exhaust pipe. Are known. In such a collecting portion, since abnormal noise is generated due to interference of inflowing exhaust gas, it is necessary to provide a small hole in each mating surface of the upstream exhaust pipe to suppress the abnormal noise.
-204915.

[0003]

However, if the positions of the small holes on the mating surfaces are not matched, there is a problem that the small holes are closed and the noise cannot be sufficiently suppressed. In addition, in order to match the positions of the small holes on the respective mating surfaces, high component accuracy and assembly accuracy are required, and there is a problem in that the cost increases in manufacturing.

Accordingly, an object of the present invention is to provide a collective structure of an exhaust pipe which can solve these problems.

[0005]

In order to achieve the above object, according to the present invention, a mating surface is formed at each downstream end of a plurality of upstream exhaust pipes, and the mating surfaces are aligned with each other. At the gathering portion of the exhaust pipes fitted to the two downstream exhaust pipes, a number of small holes are provided on the mating surface of one of the upstream exhaust pipes, and the number of small holes are formed on the mating surface of the other upstream exhaust pipe. An exhaust pipe collecting part structure in which notches are provided in opposing parts.

According to a second aspect of the present invention, a joint surface is formed at each downstream end of a plurality of upstream exhaust pipes, and the mating surfaces are aligned and inserted into one downstream exhaust pipe. , A plurality of small holes are provided in a mating surface of one of the upstream exhaust pipes, and a cutout is provided in an entire surface of the mating surface of the other upstream exhaust pipe. .

According to a third aspect of the present invention, there is provided a set of exhaust pipes in which a mating surface is formed at each downstream end of a plurality of upstream exhaust pipes, and the mating surfaces are aligned and inserted into one downstream exhaust pipe. In the part, the insertion allowance of one upstream exhaust pipe is set longer than the insertion allowance of the other upstream exhaust pipe, and the insertion allowance of the other upstream exhaust pipe out of the insertion allowance of the one upstream exhaust pipe. And a plurality of small holes provided in a portion longer than the length of the exhaust pipe.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, preferred embodiments of the present invention will be described with reference to the drawings. [Embodiment 1] As shown in FIGS. 1 (a) to 1 (e), the downstream ends of the upstream exhaust pipes 1 and 2 are molded to have a substantially semicircular cross section, and the mating surfaces 1a and 2a are formed respectively.

A substantially semicircular notch 5 is provided at the downstream end of the mating surface 2a of one upstream exhaust pipe 2. A plurality of small holes 4 are provided in a portion facing the notch 5 in the mating surface 1a.

The downstream ends of the two upstream exhaust pipes are inserted into the downstream exhaust pipe 3 with the two mating surfaces 1a and 2a aligned with each other. [Embodiment 2] As shown in FIGS. 2 (a) to 2 (e), the downstream ends of the upstream exhaust pipes 1 and 2 are molded into a substantially semicircular cross-section to form mating surfaces 1a and 2a, respectively. One upstream exhaust pipe 2
The notch 5 is provided on substantially the entire surface of the mating surface 2a. As a result, the mating surface 2a is almost eliminated. In addition, FIG.
In (e), the notch 5 provided in the mating surface 2a of the upstream exhaust pipe 2 is shown in FIGS. (B), (c) and (e).
The mating surface 2a itself is not shown. In FIG. 4C, the reference numeral 2a with parentheses is also shown along with the notch 5, but the mating surface itself at the portion with this reference numeral (2a) is almost eliminated by providing the notch 5. ing. In other words, the mating surface 2a of the one upstream exhaust pipe 2 is formed temporarily in a manufacturing process before the notch 5 is provided,
After the notch 5 is provided, both upstream exhaust pipes are assembled so that the so-called peripheral portion (2a) of the mating surface 2a faces the other mating surface 1a.

However, before assembling, a plurality of small holes 4 are provided on substantially the entire mating surface 1a. Finally, the mating surface 1a and the notch 5 (or the peripheral portion (2a)) are aligned, and the downstream ends of both the upstream exhaust pipes 1 and 2 are inserted and fixed to the upstream end of the downstream exhaust pipe 3. I do.

Third Embodiment A third embodiment will be described with reference to FIGS. The downstream end portions of the upstream side exhaust pipes 1 and 2 are molded so that the cross section is substantially semicircular,
a and 2a are formed.

The length of the mating surface 1a in the axial direction of the exhaust pipe 1 is set longer than the length of the mating surface 2a in the axial direction of the exhaust pipe 2. Reference numeral 6 is attached to a portion (so-called difference portion) of the length of the mating surface 1a which is larger than the length of the mating surface 2a.

A plurality of small holes 4 are provided in the difference portion 6 at the downstream end of the mating surface 1a. The respective mating surfaces 1a and 2a are aligned, and inserted and fixed to the downstream side exhaust pipe 3. The difference 6
There is no portion of the mating surface 2a that is to be opposed and aligned.
The length of the difference portion 6 is arbitrarily set.

Fourth Embodiment Next, a fourth embodiment will be described with reference to FIGS. The downstream ends of the upstream-side exhaust pipes 1 and 2 are molded into a substantially semicircular cross section, and the mating surfaces 1a and 2
a is formed.

A square U-shaped notch 5 is provided at the downstream end of the mating surface 2a. A plurality of small holes 4 are provided in a portion facing the notch 5 in the mating surface 1a. With the mating surfaces 1a and 2a aligned, the downstream ends of both upstream-side exhaust pipes are inserted into the downstream-side exhaust pipes 3, and fixed and connected.

In each of the above embodiments, the downstream ends of the upstream exhaust pipes 1 and 2 are formed into a substantially semicircular cross section and inserted into the circular downstream exhaust pipe. The part may be formed in an elliptical shape, and the downstream ends of the upstream exhaust pipes 1 and 2 may be formed into a shape obtained by equally dividing the ellipse and inserted.

In the above embodiment, the mating surface 1
Although the planes a and 2a are planes, the planes are not necessarily limited to planes, and irregularities may be provided for absorbing thermal stress and positioning. Further, the number of upstream exhaust pipes 3 and the number and diameter of the small holes 4 are arbitrarily set.

[0019]

Since the exhaust pipe collecting portion structure of the present invention is constructed as described above, the exhaust pipes on the upstream side are fixed in surface contact with each other except for the cutout portion. There is no stress concentration, which is advantageous in strength.

In addition, it is not necessary to make the positions of the small holes on both mating surfaces coincide with each other, and the small holes are not closed, so that noise can be suppressed reliably. Since the positions of the small holes on the mating surfaces do not need to be matched, high component accuracy and assembly accuracy are not required, and cost reduction in manufacturing can be expected.

Further, according to the second aspect of the present invention, since the number of small holes can be set more, the effect of suppressing abnormal noise is great. Further, since high surface accuracy is not required for the mating surfaces, it can be manufactured more easily.

According to the third aspect of the present invention, since only the length of the upstream exhaust pipes is changed and a step of providing a notch is not required, the production can be further facilitated.

[Brief description of the drawings]

FIGS. 1A and 1B are diagrams illustrating Embodiment 1 of the present invention, wherein FIG. 1A is a perspective view of a state in which a downstream exhaust pipe is not assembled, FIG. 1B is a cross-sectional view of both upstream exhaust pipes, and FIG. Is a plan view of a main part in an assembled state, (d) is a sectional view taken along line AA of (c), and (e) is a sectional view taken along line BB of (c).

FIGS. 2A and 2B are diagrams illustrating a second embodiment of the present invention, wherein FIG. 2A is a perspective view of a state in which a downstream exhaust pipe is not assembled, FIG. 2B is a cross-sectional view of both upstream exhaust pipes, and FIG. Is a plan view of a main part in an assembled state, (d) is a sectional view taken along line AA of (c), and (e) is a sectional view taken along line BB of (c).

3A and 3B are diagrams illustrating a third embodiment of the present invention, in which FIG. 3A is a perspective view of a state where a downstream exhaust pipe is not assembled, FIG. 3B is a cross-sectional view of both upstream exhaust pipes, and FIG. Is a plan view of a main part in an assembled state, (d) is a sectional view taken along line AA of (c), and (e) is a sectional view taken along line BB of (c).

4A and 4B are diagrams illustrating a fourth embodiment of the present invention, wherein FIG. 4A is a perspective view of a state in which a downstream exhaust pipe is not assembled, FIG. 4B is a cross-sectional view of both upstream exhaust pipes, and FIG. Is a plan view of a main part in an assembled state, (d) is a sectional view taken along line AA of (c), and (e) is a sectional view taken along line BB of (c).

[Explanation of symbols]

 1, 2 upstream exhaust pipe 1a, 2a mating surface 3 downstream exhaust pipe 4 small hole 5 notch

Claims (3)

[Claims] A joint surface is formed at each downstream end of a plurality of upstream exhaust pipes, and the mating surfaces are aligned and one of the upstream exhaust pipes is inserted into one downstream exhaust pipe. A plurality of small holes provided on a mating surface of the exhaust pipe on the side, and a cutout provided on a portion of the mating surface of the other exhaust pipe facing the plurality of small holes. Construction. 2. An exhaust pipe assembly, wherein a mating surface is formed at each downstream end of a plurality of upstream exhaust pipes, and the mating faces are aligned and inserted into one downstream exhaust pipe. A plurality of small holes are provided on the mating surface of the side exhaust pipe, and a notch is provided on the entire mating surface of the other upstream exhaust pipe. 3. An exhaust pipe assembly, in which a mating surface is formed at each downstream end of a plurality of upstream exhaust pipes, and the mating surfaces are aligned and inserted into one downstream exhaust pipe. The insertion allowance of the side exhaust pipe is set longer than the insertion allowance of the other upstream exhaust pipe, and a portion of the insertion allowance of the one upstream exhaust pipe that is longer than the insertion allowance of the other upstream exhaust pipe. An exhaust pipe collecting structure, wherein a number of small holes are provided in the exhaust pipe.