JP6546049B2 - Collective structure of exhaust pipe - Google Patents

Description

  The present invention relates to a collective structure of exhaust pipes in which a plurality of exhaust pipes are collected.

  Conventionally, as shown in Patent Document 1, when a plurality of exhaust pipes are attached to the collecting pipe, each exhaust pipe is inserted into the collecting pipe, and as a result, the exhaust gas of each exhaust pipe is the collecting pipe It was supposed to gather at.

JP-A-9-296724

  Here, in the collective structure of the exhaust pipe as shown in Patent Document 1, the exhaust pipes inserted into the collecting pipe come into contact with each other, and there is a problem that the temperature of the exhaust pipe rises.

  Then, an object of the present invention is to provide a collective structure of exhaust pipes which can suppress a temperature rise of the exhaust pipes in a collective structure in which a plurality of exhaust pipes are gathered.

The present invention
A collective structure for collecting a plurality of exhaust pipes in a collective pipe,
A collective pipe in which two or more exhaust passages are formed by partition walls formed inside, exhaust gases of the respective exhaust pipes are led to the respective exhaust passages, and the exhaust gases merge after passing through the exhaust passages;
And an extension pipe provided for each of the exhaust pipes,
The two adjacent extension pipes are disposed on both sides in the thickness direction of the partition wall, and connected to the partition wall, respectively.

  According to the above configuration, since a predetermined gap space corresponding to the thickness of the partition wall is formed between two adjacent extension pipes, it is possible to suppress the temperature rise of the extension pipes. Further, by setting the thickness of the partition wall, the predetermined gap space can be formed with high accuracy. As a result, even if the temperature increase and the exhaust pressure change are received, the extension pipes can be prevented from coming into contact with each other, and the gap space can be prevented from becoming excessive or insufficient.

  In short, according to the present invention, it is possible to provide an exhaust pipe assembly structure capable of suppressing the temperature rise of the exhaust pipe.

It is a perspective view of a collective structure of an exhaust pipe concerning an embodiment of the present invention. It is a perspective view from the direction different from FIG. 1 of the assembly structure of the exhaust pipe of FIG. It is a top cross-sectional view of the assembly structure of an exhaust pipe. FIG. 4 is a vertical cross-sectional view of FIG. 3 along IV-IV. It is a VV longitudinal cross-sectional view of FIG. FIG. 6 is a vertical sectional view taken along the line VI-VI of FIG. 3; It is a VII-VII longitudinal cross-sectional view of FIG. It is a VIII-VIII longitudinal cross-sectional view of FIG. FIG. 9 is a longitudinal sectional view taken along the line IX-IX of FIG. 3; It is a longitudinal cross-sectional view of the extension pipe of the part into which the vibration suppression member is inserted.

  FIG. 1 is a perspective view of a collective structure of exhaust pipes according to an embodiment of the present invention, and FIG. 2 is a perspective view of the collective structure of exhaust pipes of FIG. 1 from a direction different from FIG. FIG. 3 is a top cross-sectional view of the collective structure of the exhaust pipe. In this embodiment, a collective structure of exhaust pipes of a four-cylinder engine of a motorcycle will be described as an example. The engine has a plurality of cylinders, specifically, four cylinders, and upstream exhaust pipes 11 to 14 are connected to the exhaust ports of the four cylinders, respectively. The upstream exhaust pipes 11 to 14 (14 is located below the upstream exhaust pipe 13) have a cylindrical shape, respectively. In addition, in FIG.1 and FIG.2, one side of the extension pipe mentioned later is penetrated and shown. Further, the upstream side and the downstream side are defined with respect to the flow direction of the exhaust gas.

  FIG. 4 is a vertical sectional view taken along the line IV-IV of FIG. As shown in FIGS. 1 to 4, the two upstream exhaust pipes 11 and 12 gradually change in cross-sectional shape from a circular shape to a fan-like shape toward the downstream side near the downstream end, respectively. It joins at the end. The upstream exhaust pipes 11 and 12 are connected to the downstream exhaust pipe 21 at the downstream end. Similarly, in the vicinity of the downstream end, the remaining two upstream exhaust pipes 13 and 14 gradually change in cross-sectional shape from a circular shape to a fan-like shape toward the downstream side and merge at the downstream end It has become. The upstream exhaust pipes 13 and 14 are connected to the downstream exhaust pipe 22 at the downstream end. The downstream side exhaust pipe 21 has a semicircular cross-sectional shape, and has a first arc surface portion 211 and a first flat portion 212. Similarly, the downstream side exhaust pipe 22 has a semicircular cross-sectional shape, and has a second arc surface portion 221 and a second plane portion 222. The downstream side exhaust pipe 21 and the downstream side exhaust pipe 22 have the same shape, and the first flat portion 212 and the second flat portion 222 face each other and are in contact with each other, and are disposed so as to be symmetrical. The downstream side exhaust pipe 21 and the downstream side exhaust pipe 22 collectively have a substantially circular cross-sectional shape.

  An extension pipe 32 is inserted at the downstream end of the downstream side exhaust pipe 21 so that the inner peripheral surface of the downstream side exhaust pipe 21 and the outer peripheral surface of the extension pipe 32 are in contact with each other. The tube 32 is connected by welding all around. Therefore, the exhaust leak from the downstream side exhaust pipe 21 to the extension pipe 32 is prevented. The cross-sectional shape of the extension pipe 32 is semicircular like the cross-sectional shape of the downstream side exhaust pipe 21 and is formed slightly smaller than the cross-sectional shape of the downstream side exhaust pipe 21. And a third flat portion 322. Similarly, the extension pipe 42 is inserted at the downstream end of the downstream side exhaust pipe 22 so that the inner peripheral surface of the downstream side exhaust pipe 22 and the outer peripheral surface of the extension pipe 42 are in contact with each other. 22 and the extension pipe 42 are connected by welding all around. Therefore, the exhaust leak from the downstream side exhaust pipe 22 to the extension pipe 42 is prevented. Then, the cross-sectional shape of the extension pipe 42 is semi-circular like the cross-sectional shape of the downstream side exhaust pipe 22 and is formed slightly smaller than the cross-sectional shape of the downstream side exhaust pipe 22 And a fourth flat portion 422.

  FIG. 5 is a VV longitudinal cross-sectional view of FIG. As shown in FIGS. 1 to 5, the extension pipe 32 and the extension pipe 42 have the same shape, and the third flat portion 322 and the fourth flat portion 422 face each other to be symmetrical. Is located in Here, the first flat surface portion 212 of the downstream side exhaust pipe 21 and the second flat surface portion 222 of the downstream side exhaust pipe 22 are in contact with each other. The inner circumferential surface of the downstream side exhaust pipe 21 is in contact with the outer circumferential surface of the extension pipe 32, and the inner circumferential surface of the downstream side exhaust pipe 22 is in contact with the outer circumferential surface of the extension pipe 42. As a result, the third flat surface portion 322 of the extension pipe 32 and the fourth flat surface portion 422 of the extension pipe 42 are not in contact with each other, and between the third flat surface portion 322 and the fourth flat surface portion 422, the first flat surface portion An upstream clearance space S1 having a width D1 of a dimension obtained by adding the thickness 212 and the thickness of the second flat portion 222 is formed. The upstream clearance space S1 communicates with the outer space of the extension pipes 32, 42 in both the upward and downward directions.

  6 is a longitudinal sectional view taken along the line VI-VI in FIG. 3, and FIG. 7 is a longitudinal sectional view taken along the line VII-VII in FIG. As shown in FIGS. 1 to 3, 6 and 7, the extension pipe 32 is inserted into the adapter body 33, and the outer peripheral surface of the extension pipe 32 and the inner peripheral surface of the adapter body 33 are in contact with each other. The extension pipe 32 and the adapter body 33 are connected by welding all around. Therefore, the exhaust leak from the extension pipe 32 to the adapter body 33 is prevented. The cross-sectional shape of the adapter body 33 is semicircular like the cross-sectional shape of the extension tube 32, and is formed slightly larger than the cross-sectional shape of the extension tube 32, and the fifth arc surface portion 331 and the fifth plane portion And 332. FIG. The adapter body 33 is formed so that the dimension in the exhaust direction is smaller than that of the extension pipe 32. Similarly, the extension pipe 42 is inserted into the adapter body 43 so that the outer peripheral surface of the extension pipe 42 is in contact with the inner peripheral surface of the adapter body 43, and the extension pipe 42 and the adapter body 43 are welded all around It is connected. Therefore, the exhaust leak from the extension pipe 42 to the adapter body 43 is prevented. The cross-sectional shape of the adapter body 43 is semicircular like the cross-sectional shape of the extension tube 42, and is formed slightly larger than the cross-sectional shape of the extension tube 42, and the sixth arc surface portion 431 and the sixth flat portion And 432. FIG. The adapter body 43 is formed so that the dimension in the exhaust direction is smaller than that of the extension pipe 42

  The adapter body 33 and the adapter body 43 have the same shape, and the fifth flat surface portion 332 and the sixth flat surface portion 432 are disposed to face each other and to be symmetrical. The adapter body 33 and the adapter body 43 together have a substantially circular cross-sectional shape. Here, the fifth plane portion 332 and the sixth plane portion 432 are in contact with each other. The outer peripheral surface of the extension pipe 32 and the inner peripheral surface of the adapter body 33 are in contact with each other, and the outer peripheral surface of the extension pipe 42 and the inner peripheral surface of the adapter body 43 are in contact with each other. As a result, the third flat surface portion 322 of the extension pipe 32 and the fourth flat surface portion 422 of the extension pipe 42 are not in contact with each other, and the fifth flat surface portion is disposed between the third flat surface portion 322 and the fourth flat surface portion 422. A downstream clearance space S2 having a width D2 of a dimension obtained by totaling the thickness 332 and the thickness of the sixth flat portion 432 is formed. The downstream clearance space S2 communicates with the outer space of the extension pipes 32, 42 in both the upward and downward directions. A width D1 of a dimension obtained by totaling the thickness of the first flat portion 212 and a thickness of the second flat portion 222, and a width D2 of a dimension obtained by combining the thickness of the fifth flat portion 332 and the thickness of the sixth flat portion 432. Is almost the same. Therefore, the width of the upstream clearance space S1 and the width of the downstream clearance space S2 are substantially the same, and the width of the clearance space S formed between the third flat portion 322 and the fourth flat portion 422 is the extension pipe 32. , 42 are substantially the same along the axial direction. Therefore, the clearance space S extends from the downstream end of the downstream side exhaust pipe 21, 22 to the upstream end of the adapter body 33, 43 along the exhaust direction.

  8 is a longitudinal sectional view taken along line VIII-VIII in FIG. 3, and FIG. 9 is a longitudinal sectional view taken along line IX-IX in FIG. As shown in FIGS. 1 to 3, 8, and 9, the adapter body 33 is inserted into the collecting pipe 5, and the outer peripheral surface of the fifth arc surface portion 331 of the adapter body 33 and the inside of the collecting pipe 5. The adapter body 33 and the collecting pipe 5 are connected by welding all around so that the circumferential surfaces are in contact with each other. Therefore, the exhaust leak from the adapter body 33 to the collecting pipe 5 is prevented. Similarly, the adapter body 43 is inserted into the collecting pipe 5 so that the outer peripheral surface of the sixth arc surface portion 431 of the adapter body 43 and the inner peripheral surface of the collecting pipe 5 are in contact with each other. 5 is connected by welding all around. Therefore, the exhaust leak from the adapter body 43 to the collecting pipe 5 is prevented. Then, the fifth flat surface portion 332 of the adapter body 33 and the sixth flat surface portion 432 of the adapter body 43 are disposed so as to face each other and contact inside the collecting pipe 5. Therefore, in the upstream end of the collecting pipe 5, the partition wall 51 is formed by the fifth flat portion 332 and the sixth flat portion 432, and as a result, the two exhaust passages 5a and 5b are formed by the partition wall 51. Exhaust gas in the pipe 5 is adapted to join one exhaust passage 5 c after passing through the partition wall 51. The outer diameter of the collecting pipe 5 becomes smaller as it goes downstream from the connection part with the adapter body 33, 43, that is, the collecting pipe 5 goes downstream from the connection part with the adapter body 33, 43 It is formed to be tapered.

  The thickness D3 of the partition wall 51 is equal to the thickness D2 of the sum of the thickness of the fifth flat surface portion 332 of the adapter body 33 and the thickness of the sixth flat surface portion 432 of the adapter body 43. Therefore, the width of the gap space S formed between the third flat surface portion 322 of the extension pipe 32 and the fourth flat surface portion 422 of the extension pipe 42 is controlled by the thickness of the partition wall 51.

  In the gap space S between the third flat surface portion 322 of the extension tube 32 and the fourth flat surface portion 422 of the extension tube 42, a plurality of pairs of opposing pairs are provided at predetermined intervals along the axial direction of the extension tubes 32 and 42. The vibration suppression member 6 is inserted as a joining member which joins a part of opposing surfaces of an extension pipe mutually. FIG. 10 is a longitudinal cross-sectional view of the extension pipes 32 and 42 in the portion where the vibration suppression member 6 is inserted. As shown in FIG. 10, the vibration suppressing member 6 has a plate shape. The vibration suppressing member 6 is attached to the third flat portion 322 and the fourth flat portion 422 by welding, and as a result, the third flat portion 322 and the fourth flat portion 422 are connected by the vibration suppressing member 6. It is supposed to be. The vibration suppressing member 6 also includes, for example, a member having a rigidity providing structure for increasing the rigidity of the flat surface of the extension tubes 32 and 42 for vibration prevention, for example, a rib.

  According to the collective structure of the exhaust pipe of the above configuration, the following effects can be exhibited.

(1) Since predetermined gap space S for the thickness of partition wall 51 is formed between extension pipes 32 and 42, temperature rise of extension pipes 32 and 42 can be controlled. By suppressing the temperature rise, the strength reduction due to the temperature rise can be suppressed, and the detachment of the partition wall 51 from the collecting pipe 5 due to the exhaust pressure can be prevented. As a result, it is possible to avoid the shape change for suppressing the strength reduction of the partition wall 51, such as thickening the partition wall 51.

(2) For example, when the extension pipes 32, 42 are in phase with each other when the phases of the exhaust gas fluctuation of the extension pipes 32, 42 are opposite to each other, the vibration at the contact part tends to be large. Since a predetermined gap space S is formed between the two 42, vibration of one extension tube is transmitted to the other extension tube as compared with the case where the extension tubes 32, 42 are in contact with each other. Can be suppressed.

(3) Since the extension pipes 32 and 42 are disposed on both sides in the thickness direction of the partition wall 51 and are respectively connected to the partition wall 51, the predetermined gap space S between the extension pipe 32 and the extension pipe 42 is It can be easily formed.

(4) By setting the thickness of the partition wall 51, the predetermined clearance space S can be formed with high accuracy. As a result, even when the temperature increase and the exhaust pressure change are received, the extension pipes 32 and 42 can be prevented from coming in contact with each other, and the gap space S can be prevented from becoming excessive or insufficient. The temperature rise of the extension pipes 32 and 42 can be suppressed while preventing.

(5) Since the extension pipes 32 and 42 are disposed adjacent to each other and connected so that the outer peripheral surface of the upstream end is in contact with the inner peripheral surface of the downstream side exhaust pipes 21 and 22, At the upstream end, a gap space corresponding to the thickness of the downstream side exhaust pipes 21 and 22 can be formed, and the downstream side exhaust pipes 21 and 22 and the partition wall 51 form an upstream and a downstream of the extension pipes 32 and 42. The accuracy of the clearance dimension at the end can be set. As a result, the extension pipes 32 and 42 do not contact each other over the entire length, and it is possible to prevent the gap space from becoming excessive or insufficient.

(6) Since the gap space S communicates with the outer space of the extension pipes 32, 42, the heat of the extension pipes 32, 42 is easily dissipated to the outer space, and the temperature of the extension pipes 32, 42 The effect of suppressing the rise can be improved.

(7) The extension pipes 32 and 42 are connected to the collecting pipe 5 via the adapter bodies 33 and 43 which are disposed adjacent to each other and have an upstream end shape corresponding to the downstream end shape of the extension pipes 32 and 42 Therefore, by adjusting the cross-sectional shapes of the adapter bodies 33 and 43, the cross-sectional shapes of the extension tubes 32 and 42 can be made uniform. Further, the downstream ends of the adapter bodies 33, 43 are connected to the collecting pipe 5, and the partition wall 51 is formed by a part of the adapter bodies 33, 43. The partition wall 51 can be formed by the opposing third flat surface portion 322, the fourth flat surface portion 422, the fifth flat surface portion 332, and the sixth flat surface portion 432 of the adapter bodies 33 and 43, and the gap between the extension tubes 32 and 42 The space S can be formed with high accuracy.

(8) The adapter bodies 33 and 43 are formed by inserting an annular body having a semicircular cross-sectional shape. Therefore, while forming a partition wall with a semicircle-shaped chord part, welding fixation to collective pipe 5 is realizable with a semicircle-shaped arc part. As a result, the partition wall 51 can be formed and fixed to the collecting pipe 5 with a simple structure.

(9) The vibration suppressing member 6 can suppress the vibration of the extension pipes 32 and 42.

(10) Since the vibration suppression member 6 is configured to weld the facing surfaces of the third and fourth flat surface portions 322 and 422 facing each other, the vibration suppression member 6 can be easily formed. Moreover, the strength of the extension pipes 32 and 42 can be improved by joining a part of the third flat surface portion 322 and a part of the fourth flat surface portion 422 to each other.

(11) The downstream side exhaust pipe 21 collects the upstream side exhaust pipes 11 and 12 and the downstream side exhaust pipe 22 collects the upstream side exhaust pipes 13 and 14. The exhaust gas from the plurality of cylinders is led to the engine 22. As a result, the exhaust pressure and temperature of the exhaust gas in the downstream side exhaust pipes 21 and 22 easily become high, and by forming the gap space S between the extension pipes 32 and 42, the temperature rise of the extension pipes 32 and 42 A greater effect can be obtained on the suppression effect.

(12) The partition wall 51 is configured to form the two exhaust passages 5a and 5b, and the extension pipes 32 and 42 are provided so as to be symmetrical left and right. Can be easily manufactured. Further, the extension pipes 32 and 42 can be easily connected.

(13) Since the gap space S communicates with the outer space in both the upper and lower directions, cool air flows in from the lower side, and the warm air flows out from the upper side, so that the gap space S and the outer space The air flow between them is promoted, and the effect of suppressing the temperature rise of the extension pipes 32, 42 can be further enhanced.

(14) When the extension pipes 32 and 42 are disposed below the engine, since the gap space S communicates with the outer space in both the upper and lower directions, foreign matter such as pebbles intrude into the gap space S. Also, foreign matter can be dropped from the space S by its own weight, and the space S can be prevented from being clogged with foreign matter. In addition, since the openings are formed in the vertical direction in the clearance space S, the clearance space S is less likely to be visually recognized as compared with the case where the openings are formed in the horizontal direction, and a reduction in the appearance can be prevented.

(15) Since the partition wall 51 of the collecting pipe 5 is formed by inserting the adapter body 33 and the adapter body 43 into the collecting pipe 5, welding is performed as compared with the case where the dividing wall is attached to the inside of the collecting pipe 5 The number of places can be increased, and the strength of the partition wall 51 can be improved. As a result, even when the exhaust pressure and the exhaust temperature are high, separation of the partition wall from the collecting pipe can be prevented.

(16) The collecting pipe 5 is tapered toward the downstream side, so that the adapter bodies 33 and 43 can be prevented from being inserted into the collecting pipe 5 more than a predetermined amount. As a result, welding can be easily performed in a state where the adapter bodies 33 and 43 and the collecting pipe 5 are positioned.

(17) Since the collecting pipe 5 is formed to be tapered toward the downstream side, the adapter body 33, even if the joint strength of the welded portion between the adapter bodies 33 and 43 and the collecting pipe 5 is lowered by the exhaust temperature. It is possible to prevent the 43 from moving downstream by the tapered structure, and it is easy to prevent the separation wall from separating from the collecting pipe.

(18) Since the cross sectional shapes of the extension pipes 32 and 42 are respectively formed in a semicircular shape, the combined shape of the extension pipes 32 and 42 can be made circular, and as a result, the shape of the collecting pipe is a circle It can be shaped. And, by making the collecting pipe circular, the collecting pipe can be easily formed.

(19) Since the cross-sectional shapes of the extension tubes 32 and 42 are each formed in a semicircular shape, vibration noise is apt to occur due to the vibration in the flat portion. However, since the vibration suppressing member 6 is provided on the flat portion, the vibration of the extension pipes 32 and 42 can be suppressed, and the temperature rise can be suppressed by the gap space S between the extension pipes 32 and 42. Therefore, according to the configuration of the present embodiment, it is possible to achieve both the heat countermeasure and the vibration countermeasure of the extension pipes 32 and 42.

(20) Since the extension pipes 32 and 42 and the adapter bodies 33 and 43 are symmetrically provided, the extension pipes 32 and 42 and the adapter bodies 33 and 43 can be made common, and the number of parts can be reduced. Can. As a result, the manufacturing costs of the extension pipes 32 and 42 and the adapter bodies 33 and 43 can be reduced.

(21) The extension pipes 32 and 42 are formed so that the dimension in the exhaust direction is larger than the adapter bodies 33 and 43, so the heat dissipation of the extension pipes 32 and 42 can be enhanced. , 42 by taking heat from the adapter bodies 33, 43, the temperature rise of the adapter bodies 33, 43 can be suppressed.

(Another embodiment)
In the above embodiment, the partition wall 51 of the collecting pipe 5 is formed by inserting the adapter body 33 and the adapter body 43 into the collecting pipe 5, but the dividing wall is attached to the inside of the collecting pipe 5 by welding Also good. In this case, the exhaust passage can be easily formed simply by welding the partition wall to the inner circumferential surface of the collecting pipe 5.

  In the said embodiment, although the opposing surface of the extension tubes 32 and 42 was plane, it is not limited to a plane, A curved surface or an uneven surface may be sufficient. The opposite surface of the extension tube can adopt a free shape for absorption and alignment of thermal stress.

  In the above embodiment, two exhaust passages 5a and 5b are formed inside the collecting pipe 5, but three or more exhaust passages may be formed.

  In the above embodiment, one vibration suppressing member 6 is provided between the extension pipe 32 and the extension pipe 42 in the vertical direction as an example. However, the vibration suppressing member 6 has an axial direction of the extension pipe In addition to the above, a plurality may be provided in the vertical direction.

  In the above embodiment, the gap space S communicates with the outer space in both the upper and lower directions, but either the upper or lower space may be closed. In addition, the air space which exhaust gas does not penetrate should just be formed between extension pipes, and a crevice space may be closed to outside space besides communicating with outside space.

  In the above embodiment, the extension pipes 32, 42 are inserted into the downstream side exhaust pipes 21, 22, but the downstream side exhaust pipe may be inserted into the extension pipes. In this case, in order to form a gap between the extension pipes on the upstream side, a separate partition member may be separately provided on the extension pipe. Also, the adapter body may be inserted into the extension pipe, and a gap may be formed between the extension pipes.

  In the above embodiment, the adapter bodies 33 and 43 are inserted into the collecting pipe 5, but the collecting pipe may be inserted into the adapter body. Moreover, although the extension pipes 32 and 42 and the adapter bodies 33 and 43 are respectively provided symmetrically in the left-right direction, they may be provided symmetrically in the vertical direction.

  The above embodiment shows an example in which the present invention is applied to an assembly structure in which two exhaust pipes are assembled into one collecting pipe after assembling the four exhaust pipes into two exhaust pipes. The present invention is not limited to the above, and can be applied to the entire assembly structure in which a plurality of exhaust pipes are assembled, and can be applied to, for example, an assembly structure in which three or more exhaust pipes are assembled in one collecting pipe. The present invention is also applicable to an assembly structure in which four exhaust pipes are assembled into two exhaust pipes.

  The present invention can be suitably applied to the exhaust pipe of a high power engine which is expected to have a high exhaust temperature. For example, it can be suitably applied to the exhaust pipe of an engine exceeding 100 horsepower. Moreover, you may apply to the exhaust pipe of the engine provided with a supercharger.

  In the above embodiment, the collective structure of exhaust pipes of a four-cylinder engine of a motorcycle is described as an example, but the present invention is not limited to the exhaust pipe of a vehicle such as a motorcycle, but various collective constructions of exhaust pipes Applicable to

  Various modifications and variations can be made to the above embodiments without departing from the spirit and scope of the present invention as set forth in the claims.

  In the present invention, since the present invention can provide a collective structure of exhaust pipes capable of suppressing a temperature rise of the exhaust pipes in a collective structure in which a plurality of exhaust pipes are gathered, industrial utility value is great. .

11 upstream exhaust pipe 12 upstream exhaust pipe 13 upstream exhaust pipe 14 upstream exhaust pipe 21 downstream exhaust pipe
211 first arc surface portion 212 first flat surface portion 22 downstream exhaust pipe 221 second arc surface portion 222 second flat surface portion 32 extension tube 321 third arc surface portion 322 third flat surface portion 33 adapter body 331 fifth arc surface portion 332 fifth flat portion 42 extension pipe 421 fourth arc surface portion 422 fourth flat portion 43 adapter body 431 sixth arc surface portion 432 sixth flat portion 5 collecting pipe 51 partition wall 6 vibration suppressing member

Claims (8)

A collective structure for collecting a plurality of exhaust pipes in a collective pipe,
A collective pipe in which two or more exhaust passages are formed by partition walls formed inside, exhaust gases of the respective exhaust pipes are led to the respective exhaust passages, and the exhaust gases merge after passing through the exhaust passages;
And an extension pipe provided for each of the exhaust pipes,
The two adjacent extension pipes are disposed on both sides in the thickness direction of the partition wall, and the outer peripheral surfaces thereof are inserted so as to be in contact with the partition wall, and are respectively connected to the partition wall,
A collection structure of exhaust pipes , wherein a gap for the thickness of the partition wall is formed between two adjacent extension pipes .   The collective structure of an exhaust pipe according to claim 1, wherein a clearance space between two adjacent ones of the extension pipes is in communication with an outer space of the extension pipe. The two adjacent extension pipes are disposed adjacent to each other, and connected such that the outer peripheral surface of the upstream end is in contact with the inner peripheral surface of the exhaust pipe,
The plurality of exhaust pipes are in contact with each other at opposing flat portions,
The collective structure of the exhaust pipe according to claim 1 or 2 , wherein the total dimension of the thickness of the flat portion is equal to the width of the thickness of the partition wall to which the extension pipe is connected . The two adjacent extension pipes are disposed adjacent to each other,
An adapter body having an upstream end shape corresponding to the downstream end shapes of the two adjacent extension tubes;
The downstream end of the adapter body is connected to the collecting pipe,
The partition wall is formed by a part of the adapter body,
The exhaust pipe collective structure according to any one of claims 1 to 3 , wherein the outer peripheral surface of the adapter body is inserted into the collecting pipe so as to be in contact with the inner peripheral surface of the collecting pipe . The aggregate structure of the exhaust pipe according to claim 4, wherein the sum of the thickness direction dimensions of the respective adapter bodies is the same as the sum of the thickness direction dimensions of the exhaust pipe. The collective structure of exhaust pipes according to any one of claims 1 to 5, wherein outer peripheries of two adjacent extension pipes have an arc shape. The outer peripheries of two adjacent extension pipes have a semicircular shape and are arranged symmetrically.
  The exhaust pipe collective structure according to any one of claims 1 to 6, wherein the collective pipe has a circular shape. The collective structure of exhaust pipes according to claim 7, wherein a vibration suppressing member for suppressing vibration of the extension pipe is provided on a semicircular flat portion of the extension pipe.

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