Title of Invention	"MUFFLER FOR MOTORCYCLE OR THE LIKE VEHICLES"
Abstract	: To provide a muffler for a small-sized, lightweight, and small-displacement motorcycle in which a catalyst is arranged in a diffuser pipe, which is capable of preventing the thermal deterioration of a tail pipe due to thermal effect caused by the exhaust gas purifying reaction of the catalyst.

Full Text

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a muffler for a motorcycle or the like, and particularly to a murrier in which a catalyst is arranged for purifying an exhaust gas. [Related Art] A muffler for a small-sized motorcycle or the like such as a scooter-type motorcycle is disclosed, for example in Japanese Patent Laid-open No. Sho 54-90421. The structure of the related art muffler will be described with reference to a schematic view of the muffler shown in Fig. 13. In Fig. 13, parts of the muffler are denoted by symbols different from those denoted in the above document for an easy understanding of the following description of the present invention. The inside of an outer cylinder 101 of a muffler 100 is partitioned, by means of partition walls 102 and 103, into three pieces of partition chambers 104, 105 and 106. Both an exhaust pipe 107 connected in fluid-communication to an exhaust manifold of an engine and a diffuser pipe 108 connected in fluid-communication to the exhaust pipe 107 are inserted in the outer cylinder 101 of the muffler 100. At this time, the diffuser pipe 108 passes through the partition wall 103 and the exhaust pipe 107 passes through the partition wall 102; and an exhaust gas discharge port of the diffuser pipe 108 is located in the rear side first chamber 106. A communication pipe 109 is arranged in such a manner as to pass through the partition walls 103 and 102 for communicating the rear side first chamber 106 to the front side second chamber 104. A communication pipe 110 is similarly arranged for communicating the front side second chamber 104 to the intermediate side third chamber 105. A tail pipe 111 is arranged in such a manner as to be communicated to the third chamber 105 by supporting an upstream end portion lla thereof inserted in the third chamber 105 by means of the partition wall 103 for partitioning the third chamber 105 from the first chamber 106. The tail pipe 111 is allowed to pass through the first chamber 106 containing the diffuser pipe 108, with a downstream end portion lllb thereof extending outward from the rear end of the outer cylinder 101. An exhaust gas fed from an engine passes through the exhaust pipe 107 and the diffuser pipe 108, and flows in the first chamber 106. The exhaust gas further flows in the second chamber 104 via the communicating pipe 109, and flows in the third chamber 105 via the communicating pipe 110. Then, the exhaust gas passes through the tail pipe 111 and is discharged from the downstream end portion lllb extending outward from the outer cylinder 101. [Problems to be Solved by the Invention] Incidentally, it may be desirable to provide a catalyst even in a small-sized motorcycle or the like for purifying an exhaust gas, and if a catalyst is provided in a muffler of the small-sized motorcycle, such a catalyst is required to be provided at a portion to which an exhaust gas fed from an engine is discharged. For the above-described related art muffler, a catalyst 112 is inevitably provided at the downstream end portion of the diffuser pipe 108 directly connected to the exhaust pipe 107, wherein the diffuser pipe 108 is arranged in the first chamber 106. Where the catalyst 112 is provided in the related art muffler 100 as described above, the diffuser pipe 108 having the catalyst 112 at the downstream end portion thereof and the tail pipe 111 are arranged close to each other in the same chamber. The catalyst 112 and the diffuser pipe 108 are heated at high temperatures by re-combustion of the exhaust gas due to the effect of the catalyst 112, so that the tail pipe 111 arranged close thereto in the same chamber is also heated. This causes a problem that deterioration of the tail pipe 111 proceeds at an early stage. To cope with the above problem, the tail pipe 111 is unavoidably made from a heat-resisting material such as a stainless steel, nickel steel, or chromium steel, to thereby increase the material cost. Also the use of such a heat-resisting material, which is generally a difficult-to-machine material, is disadvantageous in terms of machining cost and productivity. The present invention has been made to solve the above problems caused in the case of arranging a catalyst in the related art muffler. An object of the present invention is to provide a muffler for a motorcycle or the like, which is capable of preventing, while arranging a catalyst in an outer cylinder of the muffler, a tail pipe for discharging an exhaust gas outward from the outer cylinder of the muffler from being thermally affected by arrangement of a catalyst, to prevent temperature rise of the tail pipe, thereby preventing degradation of the tail pipe due to the temperature rise, resulting in improvement of the service life and durability of the tail pipe. Another object of the present invention is to provide a muffler for a motorcycle or the like, which is capable of arranging the tail pipe led from the outer cylinder of the muffler at an inconspicuous portion from outside the motorcycle, thereby improving the appearance characteristic of the motorcycle. [Means for Solving the Problems] To solve the above problems, according to an invention described in claim 1, there is provided a muffler for a motorcycle or the like in which the inside of an outer cylinder of the muffler is partitioned into a plurality of partition chambers by means of a plurality of partition walls, wherein an exhaust gas fed from an exhaust pipe is sequentially introduced into the plurality of partition chambers and is then discharged outward from the muffler, characterized in that an end portion of a diffuser pipe communicated to the exhaust pipe is located in one partition chamber of the plurality of partition chambers and a catalyst is provided at the end portion of the diffuser pipe; and a tail pipe communicated to an exhaust gas discharge port is connected to another partition chamber of the plurality of partition chambers, which chamber is spaced from the one partition chamber containing the catalyst, and the tail pipe extends rearward from the another partition chamber along the outer surface of the muffler. Since the tail pipe is partitioned, in the outer cylinder of the muffler, from the catalyst arranged i therein, it is possible to prevent the tail pipe from being thermally affected by the catalyst heated at a high temperature, and also eliminate the necessity of use of a heat-resisting steel or the like as a material of the tail pipe. The present invention relates to a muffler for a motorcycle or the like vehicles, wherein the inside of an outer cylinder of said muffler is partitioned into a plurality of partition chambers by means of a plurality of partition walls, wherein an exhaust gas fed from an exhaust pipe is sequentially introduced into said plurality of partition chambers and is then discharged outward from said muffler, characterized in that an end portion of a diffuser pipe communicated to said exhaust pipe is located in one partition chamber of said plurality of partition chambers and a catalyst is provided at the end portion of said diffused pipe and a tail pipe communicated to an exhaust gas discharge port is connected to another partition chamber of said plurality of partition chambers, which chamber is spaced from said one partition chamber containing said catalyst, and said tail pipe extends rearward from said another partition chamber along the outer surface of said muffler. [Brief Description of the Accompanying Drawings] [Fig. 1] A side view showing the appearance of one example of a motorcycle. [Fig. 2] A side view showing the appearance of a first embodiment of a muffler. [Fig. 3] A sectional view taken on line 3-3 of Fig. 2. [Fig. 4] A sectional view taken on line 4-4 of Fig. 3 showing the muffler in the state shown in Fig. 2. . [Fig. 5] A sectional view taken on line 5-5 of Fig. 3 showing the muffler in the state shown in Fig. 2. [Fig. 6] A rear view of the muffler showing a positional relationship between the muffler and a rear wheel. [Fig. 7] A side view showing the appearance of a second embodiment of the muffler. [Fig. 8] A sectional view taken on line 8-8 of Fig. 7. [Fig. 9] A sectional view taken on line 9-9 of Fig. 8 showing the muffler in the state shown in Fig. 7. [Fig. 10] A sectional view taken on line 10-10 of Fig. 8 showing the muffler in the state shown in Fig. 7. [Fig. 11] A sectional view taken on line 11-11 of Fig. 8 showing the muffler in the state shown in Fig. 7. [Fig. 12] A rear view of the muffler showing a positional relationship between the muffler and the rear wheel. [Fig. 13] A sectional side view illustrating a related art muffler. [Mode for Carrying Out the Invention] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In addition, the drawings should be viewed in the orientation of symbols. Fig. 1 is a side view showing the appearance of a motorcycle to which the present invention is applied; Fig. 2 is a side view of the appearance of a first embodiment of a muffler of the present invention; Fig. 3 is a sectional view taken on line 3-3 of Fig. 2; Fig. 4 is a sectional view taken on line 4-4 of Fig. 3 showing the state shown in Fig. 2; Fig. 5 is a sectional view taken on line 5-5 of Fig. 3 showing the state shown in Fig. 2; Fig. 6 is a rear view of the muffler showing a positional relationship with a rear wheel; Fig. 7 is a side view showing the appearance of a second embodiment of the muffler of the present invention; Fig. 8 is a sectional view taken on line 8-8 of Fig. 7; Fig. 9 is a sectional view taken on line 9-9 of Fig. 8 showing the state shown in Fig. 7; Fig. 10 is a sectional view taken on line 10-10 of Fig. 8 showing the state shown in Fig. 7; Fig. 11 is a sectional view taken on line 11-11 of Fig. 8 showing the state shown in Fig. 7; and Fig. 12 is a rear view of the muffler showing a positional relationship with the rear wheel. In these figures, symbols Fr, Rr, L and R which are added with arrows denote the front, rear, left, and right sides of the motorcycle in the direction viewed from the driver, respectively. Referring to Fig. 1, there is shown a motorcycle 1 representative of a scooter-type vehicle to which the present invention is applied. A head pipe 2a is mounted to the front end of a frame 2. A front fork 4 for supporting a front wheel 3 is steerably supported by the head pipe 2a. A steering shaft 4a extends upward from the head pipe 2a, and a steering handlebar 5 is provided on the upper end of the steering shaft 4a. The frame 2 has a front half 2b extending at a low level. In addition, the front half 2b and later portions of the frame 2 are each composed of right and left members. A fuel tank 6 is arranged between the right and left members of the front half 2b. The frame 2 includes the front half 2b, a seat post 2c, and a rear portion 2d. The seat post 2c is sharply raised from the rear end of the front half 2b and extends rearward, obliquely upward, and the rear portion 2d extends rearward, slowly obliquely upward from the upper end of the seat post 2c. A seat 7 is arranged over both the seat post 2c and the rear portion 2d. Brackets 2e are provided on the lower surfaces of the right and left members of a curved portion which is the boundary between the seat post 2c and the rear portion 2d, and the upper portion of the front half of a power unit 9 is pivotably supported by the brackets 2e via links 8. The power unit 9 includes at its front portion an engine 10 tilting forward, upward. A transmission case 11 serving as a crank case extends rearward from the rear end of the engine 10, and supports at its rear portion a rear heel 12 as a drive wheel. Bosses, which project upward from the transmission case 11 at positions directly after the engine 10, are pivotably supported by the links 8, so that the unit swing type power unit 9 is swingably supported by the frame 2. Bosses are provided on the rear portion of the transmission case 11 of the power unit 9 in such a manner as to project upward therefrom, and rear cushion units 13 are interposed between the rear half of the rear portion 2d of the frame 2 and the bosses. An exhaust pipe 28 projecting downward from the engine 10 extends rearward on the right side of the motorcycle. The rear end of the exhaust pipe 14 is connected to the upstream side of a muffler 30 which extends rearward from the power unit 9. The muffler 30 is supported by the power unit 9 including the engine via a muffler stay. The outer surface of the frame 2 is covered with a front cover 14, a floor 15, a seat post cover 16, and a rear cover 17 arranged in this order from the front of the body. The appearance of the body is constituted by these covers. In the figure, reference numeral 18 denotes an oil tank arranged in the rear of the rear portion 2d of the frame 2; 19 is a rear carrier; 20 is the rear half of a rear fender; 21 is a front fender; 22 is a battery arranged in the front cover 14; 23 is a headlamp; and 24 is one of right and left rear view mirror. Reference numeral 25 denotes an intake system mounted on and supported by the transmission case 11 of the power unit 9. The intake system 25 is composed of an air cleaner 26 arranged on the outer side, and an intake chamber 27 arranged on the inner side. The muffler 30 of the present invention will be described in detail below. The muffler 30 is, as described above, mounted on and supported by the transmission case 11, with its rear half extending rearward from the transmission case 11 as shown in Fig. 1. The muffler 30 is connected in fluid-communication to the downstream end portion of the exhaust pipe 28 connected in fluid-communication to an exhaust manifold of the engine 10. Figs. 2 to 6 show a first embodiment of the muffler 30 of the present invention. The muffler 30 has an outer cylinder 31 whose diameter is slightly increased from front to rear. The outer cylinder 31 constitutes the appearance of the muffler 30. The front end portion of the outer cylinder 31 is closed with a front end closing plate 32, and the rear end portion of the outer cylinder 31 is closed with a rear end closing plate 33. The inside of the outer cylinder 31 is partitioned, by means of partition plates spaced in the axial direction, for example, two partition plates 34 and 35 shown in Fig. 2, into a rear side first chamber 36, a front side second chamber 37, and an intermediate side third chamber 38. Inner cylinder members 39 and 40, each of which is made from a punching metal or the like, are respectively arranged on the outer peripheral sides of the chambers 36 and 38 with gaps put between the inner peripheral surface of the outer cylinder 31 and the same. In the front end portion of the front side second chamber 37, an end plate 41 made from a punching metal or the like is arranged inside the front end closing plate 32. Similarly, an end plate 42 made from a punching metal or the like is arranged inside the rear end closing plate 33. Spaces between the outer surfaces of these inner cylinder members 39 and 40 and the outer cylinder 31 are respectively filled with sound absorbing materials 43, and similarly, spaces between the end plates 41 and 42 and the closing plates 32 and 33 are respectively filled with the sound absorbing materials 43. A diffuser pipe 44 longer in the axial direction is axially inserted in the outer cylinder 31. The diffuser pipe 44 shown in the figure is tapered with the diameter being small at the front portion and gradually, slightly enlarged toward the rear portion, and it passes through the front end closing plate 32 and the inner partition plates 34 and 35. The rear portion, that is, the downstream end portion of the diffuser pipe 44 is located in the rear of the rear side first chamber 36. The diffuser pipe 44 is fixed in the outer cylinder 31 such that an upstream end portion (front end portion) 44a penetrates the central portion of the front end closing plate 32 and fixed thereto; the front portion of a front half 44b axially passes through the second chamber 37, penetrating the front side partition plate 34, and is fixed thereto; and the rear portion of the front half 44b axially passes through the third chamber 38, penetrating the rear side partition plate 35, and is fixed thereto. A rear half 44c of the diffuser pipe 44 is located in the first chamber 36, with its downstream end portion 44d opened in the first chamber 36. In the embodiment shown in the figure, the rear half portion of the diffuser pipe 44, located in the first chamber 36, has a double-pipe structure in which a holder cylinder 45 is provided around the outer periphery of the rear half 44c made from a punching metal or the like and a space between the rear half 44c and the holder cylinder 45 is filled with the sound absorbing material 43. Connected to the rear end of the diffuser pipe 44 is a catalyst 46 of a honeycomb structure made from a stainless steel in which a catalyst element representative of a noble metal such as platinum-rhodium is supported. A first communicating pipe 47 for connecting the rear side first chamber 36 in fluid-communication to the front side second chamber 37 is mounted between the rear side partition plate 35 and the front side partition plate 34. A second communicating pipe 48 for connecting the front side second chamber 37 in fluid-communication to the intermediate side third chamber 38 is mounted on and supported by the front side partition plate 34 for partitioning the second chamber 37 from the third chamber 38 in such a manner as to pass through the front side partition plate 34. With this arrangement, the rear side first chamber 36 communicated to the diffuser pipe 44 is connected in fluid-communication to the front side second chamber 37, and also the second chamber 37 is connected in fluid-communication to the intermediate side third chamber 38. As shown in Fig. 4, a front end portion (upstream end portion) 49a of a tail pipe 49 penetrates, from outside, the outer cylinder 31 at a position equivalent to that of the third chamber 38 located at the intermediate portion in the axial direction of the outer cylinder 31, so that the tail pipe 49 is connected in fluid-communication to the third chamber 38. A front portion 49b of the tail pipe 49 is bent into an L-shape toward the outer cylinder 31. The front end portion 49a of the front portion 49b thus bent penetrates the outer cylinder 31 and the inner cylindrical member 40 to be inserted in and fixed to the third chamber 38. That is to say, the front end portion 49a of the tail pipe 49 penetrates, from outside, the outer cylinder 31 and the inner cylindrical member 40 in the radial direction. The tail pipe 49, which is spaced from the outer periphery of the outer cylinder 31 with a gap put therebetween, extends rearward along the axial direction of the outer cylinder 31 in parallel thereto. Fig. 6 shows a positional relationship between the tail pipe 49 and the outer cylinder 31. As shown in Fig. 6, the tail pipe 49 is arranged to be offset onto the rear wheel 12 side, that is, onto the body center side, in order not to be directly viewed from a side (right side) of the motorcycle. In addition, a rear end portion (downstream end portion) 49c of the tail pipe 49 is tilted downward. The rear portion of the above tail pipe 49 in the length direction is supported by a stay 50 suspended from a lower portion, on the body center side, of the outer cylinder 31. The front end portion (upstream end portion) 44a of the diffuser pipe 44 of the muffler 30 is connected to a downstream portion 29 of the exhaust pipe 28, whereby the inside of the exhaust pipe 28 is connected in fluid-communication to the inside of the diffuser pipe 44. Such a state is shown in Fig. 2. Referring to Fig. 2, a supporting stay 51 is integrally provided on both the front portion of the muffler 30 and the downstream portion 29 of the exhaust pipe 28 in such a manner as to project therefrom, and the muffler 30 is mounted on and supported by the transmission case 11 of the power unit 9 via the supporting stay 51. In the above muffler 30, an exhaust gas fed from the engine 10 flows in the diffuser pipe 44 of the muffler 30 via the exhaust pipe 28 and the downstream portion 29 of the exhaust pipe 28. The exhaust gas is re-burned by the catalyst 46 connected to the downstream end portion 44d of the diffuser pipe 44 arranged in the rear side first chamber 36, to be thus purified, and is discharged in the first chamber 36. The catalyst 46, and the rear half 44c of the diffuser pipe 44 including the downstream end portion 44d are heated at high temperatures by the exhaust gas purifying reaction of the catalyst. The exhaust gas flows in the front side second chamber 37 via the first communicating pipe 47, and then flows in the intermediate side third chamber 38 via the second communicating pipe 48. During the above step, the noise level of the exhaust gas is reduced by the sound absorbing materials, and thereafter, the exhaust gas is discharged to outside air from the tail pipe 49 having the front end portion 49a opened in the third chamber 38. As described above, in this embodiment, while the catalyst is inevitably mounted to the diffuser pipe 44 like the related art muffler, the front end portion 49a, as the flow-in port of an exhaust gas, of the tail pipe 49 is arranged in the third chamber 38 partitioned from the diffuser pipe 44 by means of the partition plate 35. As a result, the tail pipe 49 is prevented from being thermally affected by the catalyst 46. Also since the tail pipe 49 projects from the third chamber 38 to the outside of the outer cylinder 31 and extends rearward along the outer cylinder 31, it is separated as a whole from the diffuser pipe 44 and the catalyst 46 heated at high temperatures in the first chamber 36 via the outer cylinder 31. As a result, the tail pipe 49 is prevented as a whole from being thermally affected by the diffuser pipe 44 and the catalyst 46. This is effective to protect the thermal deterioration of the tail pipe 49 and hence to improve the service life and the durability thereof. As shown in Fig. 6, the tail pipe 49 is located outside the outer cylinder 31 constituting the muffler main body at a position offset on the body center side and it extends rearward along the outer cylinder 31, and accordingly, the tail pipe 49 is not directly exposed on the right side of the motorcycle on which the muffler 30 is arranged. This is effective to make inconspicuous the tail pipe 49 from the right side of the motorcycle and hence to improve the appearance of the muffler 30. Figs. 7 to 12 show a second embodiment of the present invention. The second embodiment has the same basic configuration as that of the first embodiment, and therefore, parts corresponding to those shown in the first embodiment are denoted by the same reference numerals and the explanation thereof is omitted. As shown in Fig. 8, the inside of an outer cylinder 31 is partitioned, by means of first, second, and third partition plates 35, 61 and 34 which are axially spaced in this order from rear to front, into first, second, third, and fourth chambers 36, 37, 63 and 38 which are arranged in this order from rear to front. Like the first embodiment, inner cylindrical members 39, 40 and 62 are respectively provided in the chambers 36, 37 and 62, with sound absorbing materials 43 interposed between the inner cylindrical members 39, 40 and 62 and the outer cylinder 31; and end plates 41 and 42 are respectively provided inside a front end closing plate 32 and a rear end closing plate 33, with sound absorbing materials 43 interposed between the end plates 41 and 42 and the outer cylinder 31. Like the first embodiment, a diffuser pipe 44 is axially inserted in the muffler 30 while axially passing through the front end closing plate 32 and the partition plates 34, 61 and 35. A catalyst 46 is connected to a downstream end portion 44d of the diffuser pipe 44 located in the rear side first chamber 36. A holder cylinder 45 is provided around the diffuser pipe 44 at a portion passing through the partition plates 35 and 61, with the above sound absorbing material 43 interposed between the holder cylinder 45 and the outer periphery of the associated portion of the diffuser pipe 44 (see Fig. 10). A first communicating pipe 47 for communicating the first chamber 36 to the second chamber 37 penetrates the first partition plate 35 and is fixed thereto; a second communicating pipe 48 for communicating the second chamber 37 to the third chamber 63 penetrates the second partition plate 61 and is fixed thereto; and a third communicating pipe 64 for communicating the third chamber 63 to the fourth chamber 38 penetrates the third partition plate 34 and is fixed thereto. In this way, the first, second, third, and fourth chambers 36, 37, 62 and 38 arranged in this order from rear to front are communicated to each other while being partitioned from each other by means of the partition plates 35, 63 and 34. The downstream end portion of the downstream portion 29 of the exhaust pipe is connected in fluid-communication to the front end portion of the diffuser pipe 44. As shown in Fig. 7, like the first embodiment, a supporting stay 51 for mounting the muffler 30 on the transmission case 11 of the power unit 9 is provided on both the upper surface of the front half of the outer cylinder 31 and the upper surface of the downstream portion 29 of the exhaust pipe. The tail pipe 49 has a front portion 49b bent into an approximately L-shape with a slightly acute angle. As shown in Fig. 8, the tail pipe 49 penetrates part of the front end closing plate 32 such that the front end portion (upstream end portion) 49a of the curved front portion 49b is located in the fourth chamber 38, and is fixed to the front end closing plate 32. The tail pipe 49 also has at its rear half a main body 49d which is connected to the curved front portion 49b extending outward from the front end closing plate 32 and which extends therefrom in parallel to the outer cylinder 31. In the embodiment shown in Fig. 8, the main body 49d is formed separately from the front portion 49b and is joined thereto by welding. The rear portion of the tail pipe 49 is mounted on and supported by the outer peripheral wall of the outer cylinder 31 via a stay 50. As shown in Fig. 12, the tail pipe 49 extends along the outer periphery of the outer cylinder 31 in a state being close thereto. Like the first embodiment, the tail pipe 49 is located on the lower side of the outer cylinder 31 at a position offset on the body center side, that is, on the rear wheel 12 side, so that the tail pipe 49 is not directly exposed on the right side of the motorcycle. This is effective to make inconspicuous the tail pipe 49 from the right side of the motorcycle and hence to improve the appearance of the muffler 30. Like the first embodiment, an exhaust gas fed from the engine flows in the diffuser pipe 44 via the exhaust pipe 28 and the downstream portion 29 of the exhaust pipe 28, and further flows in the first chamber 36 through the catalyst 46 at the downstream end portion of the diffuser pipe 44. Then, the exhaust gas flows in the second chamber 37 via the communicating pipe 47, and further flows in the third chamber 63 via the communicating pipe 48. Further,the exhaust gas flows in the final front side fourth chamber 38 via the communicating pipe 64, and is discharged from the tail pipe 49. Even in this embodiment, the front end portion, as the flow-in port of an exhaust gas, of the tail pipe 49 is separated from the rear portion, particularly, the rear end of the diffuser pipe 44 heated at a high temperature, and further it is located at a position which is most apart from the rear end of the diffuser pipe 44 and is partitioned therefrom by means of the partition plates 35, 61 and 34. Also since the main body 49d of the tail pipe 49 is arranged outside the outer cylinder 31, it is most remote from the thermal effect caused by the catalyst. As a result, even in the case where a catalyst is arranged in the muffler, it is possible to prevent the thermal deterioration of the tail pipe 49. [Effect of the Invention] The present invention having the above configuration exhibits the following effects: According to the invention described in claim 1, there is provided a muffler for a motorcycle or the like in which the inside of an outer cylinder of the muffler is partitioned into a plurality of partition chambers by means of a plurality of partition walls, wherein an exhaust gas fed from an exhaust pipe is sequentially introduced into the plurality of partition chambers and is then discharged outward from the muffler, characterized in that an end portion of a diffuser pipe communicated to the exhaust pipe is located in one partition chamber of the plurality of partition chambers and a catalyst is provided at the end portion of the diffuser pipe; and a tail pipe communicated to an exhaust gas discharge port is connected to another partition chamber of the plurality of partition chambers, which chamber is spaced from the one partition chamber containing the catalyst, and the tail pipe extends rearward from the another partition chamber along the outer surface of the muffler. Accordingly, the tail pipe can be arranged at a position apart from a catalyst portion, heated at a high temperature, which catalyst portion is provided at the end portion of the diffuser pipe. Accordingly, even when a catalyst is incorporated in a small-sized, lightweight, and small displacement muffler for purifying an exhaust gas, it is possible to prevent the thermal deterioration of a tail pipe, and hence to improve the service life and the durability of the tail pipe. Further, the tail pipe can be formed of an inexpensive, easy-to-form steel plate without use of an expensive, difficult-to-form material such as a heat-resisting steel. This is advantageous in terms of the i economical efficiency. 4' ""[Reference Numerals] 1: motorcycle, 28, 29: exhaust pipe, 30: muffler, 31: outer cylinder, 34, 35, 61: partition plate as partition wall, 36, 37, 38, 63: partition chamber, 44: diffuser pipe, 46: catalyst, 49: tail pipe, 12: rear wheel on inner side of vehicular body ] We claim: 1. A muffler for a motorcycle (1) or the like vehicles, wherein the inside of an outer cylinder (31) of said muffler (30) is partitioned into a plurality of partition chambers by means of a plurality of partition walls, wherein an exhaust gas fed from an exhaust pipe is sequentially introduced into said plurality of partition chambers and is then discharged outward from said muffler (30), characterized in that an end portion of a diffuser pipe (44) communicated to said. exhaust pipe is located in one partition chamber (63) of said plurality of partition chambers and a catalyst is provided at the end portion of said diffused pipe (44) and a tail pipe (49) communicated to an exhaust gas discharge port is connected to another partition chamber of said plurality of partition chambers, which chamber is spaced from said one partition chamber containing said catalyst (46), and said tail pipe (49) extends rearward from said another partition chamber along the outer surface of said muffler (30). 2. A muffler for a motorcycle and the like vehicles substantially as herein described with reference to the accompanying drawings.

Documents:

3563-del-1998-abstract.pdf

3563-del-1998-claims.pdf

3563-del-1998-correspondence-others.pdf

3563-del-1998-correspondence-po.pdf

3563-del-1998-description (complete).pdf

3563-del-1998-drawings.pdf

3563-del-1998-form-1.pdf

3563-del-1998-form-13.pdf

3563-del-1998-form-19.pdf

3563-del-1998-form-2.pdf

3563-del-1998-form-3.pdf

3563-del-1998-form-4.pdf

3563-del-1998-form-6.pdf

3563-del-1998-gpa.pdf

3563-del-1998-petition-137.pdf

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