JP2012184713A - Exhaust muffler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce ventilation resistance, and to impart a simple structure to an exhaust muffler while improving design flexibility and installability by suppressing increase of the number of components, in the exhaust muffler wherein a plurality of inflation chambers sequentially circulating exhaust gas from an exhaust pipe communicating with an engine are formed in a casing having a cylinder part.SOLUTION: A plurality of partitions 18, 19, 20, 21 having circular or arc-shaped cross sections which have different diameters and are concentrically disposed form the plurality of inflation chambers 6-10 adjacent in the radial direction of the cylinder part 13 inside the casing 12 in a state that the partitions 18-21 are mutually interposed, and are fixedly disposed inside the casing 12. The plurality of partitions 18-21 are formed with communication holes 23, 24, 25, 26 communicating the insides and the outsides of the partitions 18-21.

Description

  The present invention relates to an exhaust muffler in which a plurality of expansion chambers for sequentially flowing exhaust gas from an exhaust pipe connected to an engine are formed in a casing having a cylindrical portion.

  The casing is partitioned into a plurality of expansion chambers by a plurality of partition walls arranged at intervals in the longitudinal direction, and the expansion chambers are communicated by a communication pipe extending between at least two partition walls among the partition walls partitioning the expansion chambers. An exhaust muffler configured to do this is known from Patent Document 1 and the like.

JP-A-8-28263

  However, in the exhaust muffler as disclosed in Patent Document 1, the exhaust gas flow becomes a turbulent flow due to the influence of a complicated inner surface shape in the casing, and the flow resistance increases. In addition, when the increase / decrease adjustment of the number of expansion chambers is performed, the structure becomes more complicated and the number of parts increases, which restricts the degree of freedom in design and assembly.

  The present invention has been made in view of such circumstances, and it is possible to keep the flow resistance low and to suppress the increase in the number of parts and to improve the degree of design freedom and assemblability and to have a simple structure. The object is to provide an exhaust muffler.

  In order to achieve the above-described object, the present invention provides an exhaust muffler in which a plurality of expansion chambers that sequentially flow exhaust gas from an exhaust pipe connected to an engine are formed in a casing having a cylindrical portion, and have different diameters. Alternatively, a plurality of partition walls arranged concentrically having an arcuate cross-sectional shape, and a plurality of the expansion chambers that are adjacent to each other in the radial direction of the cylindrical portion with the partition walls interposed therebetween. The first feature is that the plurality of partition walls are each provided with a communication hole that communicates between the inside and the outside of the partition walls.

  Moreover, in addition to the structure of the 1st characteristic, this invention makes it the 2nd characteristic that the said communicating hole is formed as a slit extended along the axial direction of the said cylinder part.

  In addition to the configuration of the first or second feature, the present invention has a third feature in that the communication holes of the partition walls adjacent in the radial direction of the cylindrical portion are arranged at positions offset in the circumferential direction. To do.

  In the present invention, in addition to the configuration of the first or second feature, at least a pair of partition walls that are part of a plurality of the partition walls and are adjacent to each other in the radial direction of the cylindrical portion have the same communication hole in the circumferential direction. A fourth feature is that the position is provided.

  Furthermore, the present invention provides the exhaust pipe at one end in the longitudinal direction of the innermost partition along the radial direction of the cylindrical portion of the plurality of partitions, in addition to any of the first to fourth features. A fifth feature is that the catalyst is accommodated and disposed in the innermost partition wall on the downstream side in the exhaust gas flow direction from the connection portion with the exhaust pipe.

  According to the first feature of the present invention, the plurality of expansion chambers adjacent in the radial direction of the cylindrical portion of the casing have a circular or arcuate cross-sectional shape with different diameters and are arranged concentrically. The partition walls are fixedly arranged in the casing, so that a plurality of expansion chambers can be formed with a simple structure, and the number of expansion chambers can be easily increased or decreased by increasing or decreasing the number of partition walls. Therefore, it is possible to suppress an increase in the number of parts and increase the degree of freedom in design and assembly. Moreover, the flow path of the exhaust gas is simpler than that of a conventional exhaust muffler in which expansion chambers are arranged in the longitudinal direction of the casing, and the flow resistance can be kept low. That is, in the conventional exhaust muffler, when the exhaust gas expands, diffuses, and contracts, the flow is disturbed by the change in the shape of the flow passage, which causes an increase in pressure loss. In the above-described configuration of the present invention that is adjacent to each other in the direction, when exhaust gas escapes from the expansion chamber on the radially inner side of the casing to the expansion chamber on the radially outer side through the communication hole, the exhaust gas is radially outward. It flows in the circumferential direction at the partition wall that defines the outer periphery of the expansion chamber on the side, and then repeatedly flows from the next communication hole to the expansion chamber on the radially outer side. Since the direction is constant, the pressure loss can be reduced, and exhaust gas escape can be improved.

  According to the second feature of the present invention, since the communication hole provided in the partition wall is a slit extending along the axial direction of the cylindrical portion, the formation of the communication hole is easy and the width of the slit can be adjusted. The flow of exhaust gas can be easily controlled.

  According to the third feature of the present invention, the communication holes of the partition walls adjacent in the radial direction of the cylindrical portion are offset in the circumferential direction, so that the pressure loss in the flow of exhaust gas can be easily changed by changing the offset amount. Can be controlled.

  According to the fourth feature of the present invention, the communication holes are provided so as to be at the same position in the circumferential direction in at least a pair of partition walls adjacent in the radial direction of the cylindrical portion, so that the expansion chamber between the partition walls serves as a resonator. Can be used.

  Furthermore, according to the fifth feature of the present invention, in the innermost partition wall along the radial direction of the cylinder portion, the exhaust gas flow direction is more than the connection portion with the exhaust pipe connected to one longitudinal end portion of the partition wall. Since the catalyst is accommodated and arranged so as to be located on the downstream side, the catalyst can be arranged in a place where high temperature can be easily maintained by introducing exhaust gas into the center of the exhaust muffler, so that early activation of the catalyst can be achieved.

It is a longitudinal cross-sectional view of the exhaust muffler of 1st Embodiment, Comprising: It is sectional drawing which follows the 1-1 line | wire of FIG. FIG. 2 is a sectional view taken along line 2-2 of FIG. FIG. 3 is a sectional view taken along line 3-3 in FIG. 2. It is sectional drawing corresponding to FIG. 3 of the exhaust muffler of 2nd Embodiment.

  Embodiments of the present invention will be described with reference to the accompanying drawings.

  The first embodiment of the present invention will be described with reference to FIGS. 1 to 3. First, in FIG. 1, for example, an exhaust pipe 5 for guiding exhaust gas from an engine E mounted on a motorcycle is an exhaust muffler according to the present invention. The exhaust muffler includes a plurality of, for example, six first to sixth expansion chambers 6, 7, 8, 9, 10, and 11 that sequentially flow exhaust gas from the exhaust pipe 5. 13 is formed in a casing 12 having 13.

  Referring to FIGS. 2 and 3 together, the casing 12 integrally has a cylindrical cylindrical portion 13 and a first short cylindrical portion 14a fixed to the outer periphery of one end of the cylindrical portion 13 on the outer periphery. A first end wall 14, a second end wall 15 integrally including a second short cylinder portion 15 a fixed to the inner periphery of the other end portion of the cylinder portion 13, and the other end portion of the cylinder portion 13 as a second short cylinder A third short cylindrical portion 16a fixed to the outer periphery of the other end portion of the cylindrical portion 13 is sandwiched between the cylindrical portion 13a and formed into a tapered shape at the large diameter end, and a discharge pipe 16b is formed at the small diameter end. It is comprised with the taper wall 16 provided coaxially and integrally.

  Among the first to sixth expansion chambers 6 to 11, the first to fifth expansion chambers 6 to 10 are formed in the casing 12 between the first and second end walls 14 and 15, and the sixth expansion chamber 11 is And formed between the second end wall 15 and the taper wall 16 of the casing 12 so as to communicate with the discharge pipe 16b. Thus, the first to fifth expansion chambers 6 to 10 include a plurality of, for example, four first to fourth partition walls 18 to 21 fixed to the first and second end walls 14 and 15 of the casing 12. It is arranged so as to be adjacent to each other in the radial direction of the cylindrical portion 13 of the casing 12.

  The first to fourth partition walls 18 to 21 have a circular or arcuate cross-sectional shape with different diameters and are concentrically arranged. The first partition wall 18 has a circular cross-sectional shape. The second partition wall 19 has an arcuate cross-sectional shape having a larger diameter than the first partition wall 18, and the third partition wall 20 has a larger diameter than the second partition wall 19. The fourth partition wall 21 has an arcuate cross-sectional shape that has a smaller diameter than the cylindrical portion 13 of the casing 12 and a larger diameter than the third partition wall 20.

  The first partition wall 18 has a large-diameter cylindrical portion 18a whose one end portion in the longitudinal direction is fixed to the first end wall 14, and one end portion coaxially and integrally connected to the other end portion of the large-diameter cylindrical portion 18a. The other end portion has a small diameter cylindrical portion 18b fixed to the second end wall 15, and is formed in a stepped cylindrical shape.

  The downstream end of the exhaust pipe 5 is connected to one longitudinal end of the first partition 18 which is the innermost partition along the radial direction of the cylindrical portion 13 of the casing 12 among the first to fourth partitions 18 to 21. In this embodiment, in the downstream end portion of the exhaust pipe 5 that is airtightly penetrated through the support cylinder portion 14 b provided in the center portion of the first end wall 14 and fixed to the first end wall 14. One end portion of the first partition wall 18 is fitted and fixed to the connecting pipe portion 5a provided, so that one end portion in the longitudinal direction of the first partition wall 18, that is, one end portion of the large-diameter cylindrical portion 18a is connected to the downstream end portion of the exhaust pipe 5. Is connected.

  Moreover, the catalyst 22 is accommodated and disposed in the first partition wall 18 on the downstream side of the connection portion with the exhaust pipe 5, in this embodiment, in the large-diameter cylindrical portion 18 a of the first partition wall 18.

  The first expansion chamber 6 is formed in the small-diameter cylindrical portion 18b of the first partition wall 18, the annular second expansion chamber 7 is formed between the first and second partition walls 18 and 19, and the annular third expansion chamber 8 is An annular fourth expansion chamber 9 is formed between the third and fourth partition walls 20 and 21, and an annular fifth expansion chamber 10 is formed between the fourth partition wall 21 and the casing. It is formed between 12 cylinder parts 13.

  The first to fourth partition walls 18 to 21 are provided with communication holes 23, 24, 25, and 26 for communicating the inside and the outside of the partition walls 18 to 21, respectively. A long hole-like communication hole 23 extending in the longitudinal direction of the first partition wall 18 is provided in the portion 18b. The communication holes 24, 25, 26 of the second to fourth partition walls 19, 20, 21 having an arcuate cross-sectional shape extend along the axial direction of the cylindrical portion 13, and the second to fourth partition walls 19-21. It is a slit covering the entire length in the longitudinal direction.

  In addition, the communication holes of the partition walls adjacent to each other in the radial direction of the cylindrical portion 13 in the casing 12 are arranged at positions offset in the circumferential direction. In the first embodiment, the communication holes 23 of the first partition wall 18 are provided. Further, the communication hole 24 of the second partition wall 19, the communication hole 24 of the second partition wall 19, the communication hole 25 of the third partition wall 20, the communication hole 25 of the third partition wall 20, and the communication hole 26 of the fourth partition wall 21 are the cylindrical portion. For example, they are arranged at positions offset by 180 degrees in the 13 circumferential directions.

  The second end wall 15 is provided with communication holes 27 and 27 for communicating the fifth expansion chamber 10 with the sixth expansion chamber 11 at a plurality of places, for example, two places spaced in the circumferential direction.

  Next, the operation of the first embodiment will be described. The first partition wall 18 having a circular cross-sectional shape and the second to fourth partition walls 19, 20, and 21 having an arc-shaped cross-sectional shape are mutually connected. The first and fourth partition walls 18 to 21 are interposed between each other and are adjacent to each other in the radial direction of the cylindrical portion 13. Fifth expansion chambers 6 to 10 are formed in the casing 12, and the first to fourth partition walls 18 to 21 have communication holes 23 to 26 for communicating between the inside and the outside of the partition walls 18 to 21, respectively. Since it is provided, the first to fifth expansion chambers 6 to 10 can be formed with a simple structure, and the increase / decrease adjustment of the number of expansion chambers can be easily performed by increasing / decreasing the number of partition walls. Suppressing the increase in the number of points, increasing design freedom and assembly It becomes possible blinking. Moreover, compared with the conventional exhaust muffler in which the expansion chambers are arranged in the longitudinal direction of the casing 12, the exhaust gas distribution path is simple, and the distribution resistance can be kept low. That is, in the conventional exhaust muffler, when the exhaust gas expands, diffuses, and contracts, the flow is disturbed due to the change in the shape of the flow passage, which causes an increase in pressure loss. In the above-described configuration of the present invention in which 10 is adjacent to the cylindrical portion 13 in the radial direction, the first expansion chamber 6 that is radially inward of the casing 12 passes through the communication hole 23 and is radially outward. When the exhaust gas escapes into the second expansion chamber 7, the exhaust gas flows in the circumferential direction at the partition wall 19 that defines the outer periphery of the second expansion chamber 8, and further enters the third expansion chamber 8 radially outward from the next communication hole 24. By repeating the flow, the first to fifth expansion chambers 6 to 10 are sequentially circulated, and the flow of exhaust gas is in a constant direction in each expansion chamber 6 to 10, so that pressure loss can be reduced. , Improve exhaust gas exhaustion Kill.

  Further, the communication holes 24 to 26 provided in the second to fourth partition walls 19 to 21 are slits extending along the axial direction of the cylindrical portion 13 and extending over the entire length in the longitudinal direction of the second to fourth partition walls 19 to 21. The communication holes 24 to 26 are easily formed, and the flow of exhaust gas can be easily controlled by adjusting the width of the slit.

  Further, the communication hole 23 of the first partition wall 18 and the communication hole 24 of the second partition wall 19, the communication hole 24 of the second partition wall 19, and the communication hole 25 of the third partition wall 20, which are adjacent to each other in the radial direction of the cylindrical portion 13 in the casing 12. Since the communication hole 25 of the third partition wall 20 and the communication hole 26 of the fourth partition wall 21 are disposed at positions offset in the circumferential direction of the cylindrical portion 13, the pressure loss in the flow of exhaust gas by changing the offset amount Can be controlled easily.

  Furthermore, the downstream end of the exhaust pipe 5 is connected to one end in the longitudinal direction of the first partition 18 which is the innermost partition along the radial direction of the cylindrical portion 13 of the casing 12 among the first to fourth partitions 18 to 21. Since the catalyst 22 is accommodated in the first partition wall 18 on the downstream side of the connection with the exhaust pipe 5, the catalyst 22 is placed in a place where high temperature can be easily maintained by introducing exhaust gas into the center of the exhaust muffler. It can arrange | position and can aim at the early activation of the catalyst 22. FIG.

  The second embodiment of the present invention will be described with reference to FIG. 4, but the parts corresponding to the first embodiment are only given the same reference numerals and shown in detail. Omitted.

  The first partition wall 18 having a circular cross-sectional shape and the second to fourth partition walls 19 to 21 having an arcuate cross-sectional shape are concentrically fixed in the cylindrical portion 13 of the casing 12 with different diameters. The first to fifth expansion chambers 6 to 10 that are adjacent to each other in the radial direction of the cylindrical portion 13 with the first to fourth partition walls 18 to 21 interposed therebetween are formed in the casing 12; The first to fourth partition walls 18 to 21 are provided with communication holes 23 to 26 that allow communication between the inside and the outside of the partition walls 18 to 21, respectively. The at least one pair of partition walls adjacent to each other in the radial direction of the cylindrical portion 13, for example, the communication holes 24 and 25 of the second and third partition walls 19 and 20, are arranged at the same position in the circumferential direction.

  According to the second embodiment, the third expansion chamber 8 formed between the second and third partition walls 19 and 20 can be used as a resonator.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various design changes can be made without departing from the present invention described in the claims. Is possible.

  For example, in the first and second embodiments, the communication hole 23 provided in the first partition wall 18 is formed in a long hole shape, but a cylindrical case filled with the catalyst 22 is placed in the first partition wall 18. The communication hole 23 may be formed as a slit so that the communication hole 23 is closed by the case at a portion corresponding to the catalyst 22.

E ... Engine 5 ... Exhaust pipes 6, 7, 8, 9, 10 ... Expansion chamber 12 ... Casing 13 ... Tube portions 18, 19, 20, 21 ... Partition 22 ...・ Catalysts 23, 24, 25, 26 ... communicating holes

Claims (5)

  A plurality of expansion chambers (6, 7, 8, 9, 10) through which exhaust gas from the exhaust pipe (5) connected to the engine (E) sequentially flows are formed in a casing (12) having a cylindrical portion (13). In the exhaust muffler, a plurality of partition walls (18, 19, 20, 21) having a circular or arcuate cross-sectional shape with different diameters and arranged concentrically, these partition walls (18-21) are arranged. A plurality of the expansion chambers (6 to 10) adjacent to each other in the radial direction of the cylindrical portion (13) are formed in the casing (12) so as to be interposed between each other and fixedly arranged in the casing (12). The plurality of partition walls (18 to 21) are provided with communication holes (23, 24, 25, and 26) for communicating between the inside and the outside of the partition walls (18 to 21), respectively. Scarf.   The exhaust muffler according to claim 1, wherein the communication hole (24-26) is formed as a slit extending along an axial direction of the cylindrical portion (13).   The said communication hole (23-26) of the said partition (18-21) adjacent to the radial direction of the said cylinder part (13) is arrange | positioned in the position offset in the circumferential direction. Exhaust muffler.   The communication holes (24, 25) are circumferentially provided in at least a pair of the partition walls (19, 20) that are part of the plurality of partition walls (23-26) and are adjacent in the radial direction of the cylindrical portion (13). The exhaust muffler according to claim 1 or 2, wherein the exhaust muffler is provided at the same position.   The exhaust pipe (5) is connected to one end in the longitudinal direction of the innermost partition wall (18) along the radial direction of the cylindrical portion (13) among the plurality of partition walls (23 to 26), and the exhaust pipe ( 5. The catalyst (22) is accommodated and disposed in the innermost partition wall (18) on the downstream side in the exhaust gas flow direction with respect to the connection portion with 5). Exhaust muffler.

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