Title of Invention

MOTORCYCLE

Abstract

It is a subject to provide a motorcycle in which it is easier to dispose a catalyzer. [Solving Means] The figure is a view as viewed from rearwardly of the vehicle body. A cross portion disposed in a vehicle widthwise direction has built therein a horizontally elongated tubular catalyzer 76 whose length L is greater than the outer diameter D thereof. Exhaust gas exhausted from an exhaust pipe front portion 3 6 flows as indicated by an arrow mark (1) and another arrow mark (2) and comes to an exhaust pipe rear portion 38. The exhaust pipe rear portion 3 8 extends between left and right rear swing arms 15L, 15R and on the right side of a mono-suspension 45 to a muffler 39. [Effect] Since the catalyzer is disposed in the vehicle widthwise direction, the catalyzer of a required length can be disposed and the purification performance can be raised without being influenced by the forward and backward length of the vehicle body. [Selected Drawing] FIG. 6

Full Text

[Name of Document] Specification [Title of the Invention] Motorcycle [Technical Field] [0001] This invention relates to arrangement of a catalyzer used in a motorcycle. [Background Art] [0002] In order to achieve purification of exhaust gas, it has become to build a catalyzer in an exhaust pipe also in a motorcycle (refer to, for example, Patent Document 1). [Patent Document 1] Japanese Patent Laid-open No. 2005-220814 (FIG. 1) [0003] In FIG. 1 of Patent Document 1, reference numeral 11 denotes a pivot shaft; reference numeral 12 denotes a rear swing arm; reference numeral 31 denotes an exhaust system; and reference numeral 47 denotes a catalyzer. The exhaust system 31 extends in a substantially longitudinal direction (leftwardly or downwardly in the drawing), and the catalyzer 47 is disposed intermediately of the exhaust system 31 such that it extends in the vehicle body longitudinal direction. In a motorcycle wherein the distance from the pivot shaft 11 to the rear wheel is small, particularly in a small motorcycle, it is difficult from a dimensional relationship to dispose a catalyzer. Therefore, a motorcycle in which it is easier to dispose a catalyzer is demanded. [Disclosure of the Invention] [Problem to be Solved by the Invention] [0005] It is a subject of the present invention to provide a motorcycle in which it is easier to dispose a catalyzer. [Means for Solving the Problem] [0006] According to the invention as set forth in claim 1, a motorcycle wherein a rear swing arm is attached for upward and downward swinging movement at a rear portion of a vehicle body frame through a pivot shaft and a rear wheel is provided at a rear portion of the swing arm while an engine is disposed forwardly of the pivot shaft and an exhaust pipe from the engine extends rearwardly, is characterized in that a catalyzer for purifying the exhaust gas is built in the exhaust pipe and has a tubular shape which has a length greater than the outer diameter thereof, and the tubular catalyzer is disposed between the pivot shaft and the rear wheel in such a manner as to extend in a vehicle widthwise direction. [0007] According to the invention as set forth in claim 2, the motorcycle is characterized in that the exhaust pipe includes a cross portion which extends in the vehicle widthwise direction, and the catalyzer is disposed in the cross portion. [0008] According to the invention as set forth in claim 3, the motorcycle is characterized in that a rear portion of the exhaust pipe which introduces the exhaust gas from the cross portion is disposed on the inner side of a seat rail as viewed in plan. [0009] According to the invention as set forth in claim 4, the motorcycle is characterized in that the rear swing arm is formed from left and right arms and a cross member extends between the arms while a rear suspension is connected at a lower portion thereof to the cross member, and a rear portion of the exhaust pipe which introduces the exhaust gas from the cross portion passes a space defined by the pivot shaft, left and right arms, and cross member. [0010] According to the invention as set forth in claim 5, the motorcycle is characterized in that a front portion of the exhaust pipe which introduces the exhaust gas from a cylinder to the cross section is disposed on the left side of the vehicle body center line as viewed in plan and the cross portion is disposed substantially at the vehicle body center as viewed in plan while a rear portion of the exhaust pipe is disposed on the right side of the vehicle body center line as viewed in plan. [0011] According to the invention as set forth in claim 6, the motorcycle is characterized in that the cross portion is disposed at a position higher than a main stand when the motorcycle travels. [0012] According to the invention as set forth in claim 7, the motorcycle is characterized in that the rear portion of the exhaust pipe is formed so as to be capable of being separated intermediately using at least one joint. [Effects of the Invention] In the invention as set forth in claim 1, since the catalyzer is disposed in such a manner as to extend in the vehicle widthwise direction, the catalyzer can be disposed in a small space between the pivot shaft and the rear wheel. Since the catalyzer is disposed in the vehicle widthwise direction, the catalyzer of a required length can be disposed and the purification performance can be raised without being influenced by the forward and backward length of the vehicle body. [0014] In the invention as set forth in claim 2, the exhaust pipe includes the cross portion which extends in the vehicle widthwise direction, and the catalyzer is disposed in the cross portion. Since both of the cross portion and the catalyzer extend in the vehicle widthwise direction, the flow of the exhaust gas becomes smooth and the flow path resistance to the exhaust gas can be reduced. [0015] In the invention as set forth in claim 3, the rear portion of the exhaust pipe which introduces the exhaust gas from the cross portion is disposed on the inner side of the seat rail as viewed in plan. The seat rail exhibits a guarding action of preventing approach to the exhaust pipe rear portion. A heat insulating protector can be omitted. [0016] In the invention as set forth in claim 4, the rear portion of the exhaust pipe which introduces the exhaust gas from the cross portion passes the space defined by the pivot shaft, left and right arms, and cross member. Since the rear portion of the exhaust pipe passes through the space, effective utilization of the space can be anticipated. [0017] Further, in the invention as set forth in claim 4, the rear swing arm is formed from the left and right arms and the cross member extends between the arms while the rear suspension is connected at the lower portion thereof to the cross member. As a result, a space is formed below the rear swing arm. Accordingly, it is possible to dispose the cross portion of the exhaust pipe and the catalyzer below and in the proximity of the rear swing arm, and the layout efficiency can be raised. [0018] Further, the entrance of the rear portion of the exhaust pipe is positioned lower than the rear swing arm, and the catalyzer is placed below the rear swing arm. The rear suspension or a link member does not exist below the rear switch arm. As a result, the arrangement space for the catalyzer can be secured sufficiently. [0019] In the invention as set forth in claim 5, the motorcycle is characterized in that the front portion of the exhaust pipe which introduces the exhaust gas from the cylinder to the cross section is disposed on the left side of the vehicle body center line as viewed in plan and the cross portion is disposed substantially at the vehicle body center as viewed in plan while the rear portion of the exhaust pipe is disposed on the right side of the vehicle body center line as viewed in plan. Therefore, a flowing manner of the exhaust gas which is suitable for the catalyzer which extends leftwardly and rightwardly in the vehicle widthwise direction can be achieved. In addition, since the rear portion of the exhaust pipe is disposed on the right side, the attention to the rider (driver) can be minimized. [0020] In the invention as set forth in claim 6, the motorcycle is characterized in that the cross portion is disposed at a position higher than a main stand when the motorcycle travels. Although earth and stone leap up from the road surface during traveling of the motorcycle, the cross portion including the catalyzer can be guarded by the main stand. In other words, a protector for protecting the catalyzer can be omitted. [0021] In the invention as set forth in claim 7, the motorcycle is characterized in that the rear portion of the exhaust pipe is formed so as to be capable of being separated intermediately using at least one joint. The rear portion of the exhaust pipe passes in the proximity of the rear suspension and is difficult to assemble. By forming this portion so as to be separable by the joint, the assembly operation can be simplified. [Best Mode for Carrying out the Invention] [0022] In the following, the best mode for carrying out the present invention is described with reference to the accompanying drawings. It is to be noted that, the drawings should be viewed in the direction of reference characters. Further, the terms forward, backward, leftward, rightward, upward, and downward are used to indicate directions taken with reference to a driver seated on a seat. FIG. 1 is a side elevational view of a motorcycle according to the present invention. The motorcycle 10 includes a mono-backbone frame 12 extending rearwardly downwards (the right side in FIG. 1 is the rear side) from a head pipe 11, and a pair of pivot plates 13L, 13R (L and R are subscripts representing the left and the right, respectively; this similarly applies in the following description). The motorcycle 10 further includes a pivot shaft 14 extending between the pivot plates 13L, 13R, a pair of rear swing arms 15L, 15R extending rearwardly from the pivot plates 13L, 13R through the pivot shaft 14 and supported for upward and downward swinging movement, and a rear axle 16 extending between the rear swing arms 15L, 15R- The motorcycle 10 further includes a rear wheel 17 mounted on the rear axle 16, a pair of left and right seat rails 18L, 18R extending rearwardly upwards from an intermediate portion of the mono-backbone frame 12, and a pair of rail stays 21L, 21R extending from the pivot plates 13L, 13R for supporting the left and right seat rails 18L, IBR. The motorcycle 10 further includes a front fork 22 mounted for steering operation on the head pipe 11 at a front portion, a front wheel 23 mounted on the front fork 22, and a steering handle bar 24 mounted at an upper end of the front fork 22. The motorcycle 10 further includes the following elements. [0024] First, a fuel tank 26 is attached to a front portion of the mono-backbone frame 12 immediately rearwardly of the head pipe 11, and an air cleaner 27 is disposed forwardly above an engine 31 below the fuel tank 26. An intake system 28 (formed from a connecting tube 28a, a throttle body 28b, and an intake manifold 18c in FIG. 3) extends downwardly rearwards from the air cleaner 27. The engine whose cylinder 2 9 extends substantially horizontally forwardly is suspended below the mono-backbone frame 12, and the intake system 28 is connected to the cylinder 29. [0025] Such an engine 31 as described above is supported on an engine supporting plate 32 and the pivot plates 13L, 13R which belong to the mono-backbone frame 12. The vehicle of the type described includes a stepping over space forwardly of a seat 19 and is of the type called cab type at which a rider (driver) places its left and right feet on left and light steps SP (refer to FIG. 2) and the engine 31 is suspended on the mono-backbone frame 12 such that the cylinder 2 9 extends substantially horizontally. [0026] Reference character CL denotes the center axis of the cylinder, and since the cylinder 2 9 extends substantially horizontally forwardly, the height of the engine 31 is reduced and a valley 33 of a V-shape in side elevation can be formed in front of the seat 19. The driver seated on the seat 19 can move the toe thereof bypassing the seat 19 forwardly by passing the toe through the valley 33. Therefore, the driver can get on and off readily without the necessity for stepping over the seat 19. [0027] An exhaust pipe 35 extending rearwardly from the cylinder 29 includes an exhaust pipe front portion 36 connecting to the cylinder 29, a cross portion 37 connected to a rear end of the exhaust pipe front portion 36 and extending from the front to the rear of the drawing, and an exhaust pipe rear portion 38 extending rearwardly upwards from the cross portion 37. A muffler 39 is connected to a rear end of the exhaust pipe rear portion 38 and disposed below the seat 19. [0028] Reference numeral 4 0 denotes a drive sprocket wheel, 41 an oiling cap, 42 a chain, 43 a stand, 44 a passenger step, 45 a mono-suspension, 46 an electric or electronic part, 47 an accommodation box, and 48 a tail pipe. [0029] FIG. 2 is a top plan view of essential part of the motorcycle according to the present invention. The fuel tank 26 is a vessel extending also in a vehicle widthwise direction and is mounted so as to extend across the mono-backbone frame 12. An oiling port 51 is provided, for example, at a portion of the fuel tank 26 on the right side of the mono-backbone frame 12 while a fuel pump attaching port 52 is provided on the left side of the mono-backbone frame 12. Reference character LL denotes the vehicle body center line (center line in the vehicle widthwise direction). [0030] The exhaust pipe front portion 3 6 extends from a location below the fuel tank 26. The exhaust pipe front portion 3 6 extends substantially along the mono-backbone frame 12 and connects to the cross portion 37 below the rail stay 21L. Then, the exhaust pipe rear portion 38 extending from the cross portion 37 extends up to the muffler 39. The muffler 39 (details are hereinafter described) fits between the left and right seat rails 18L, 18R. [0031] FIG. 3 is a side elevational sectional view of essential part of the motorcycle according to the present invention. In FIG. 3, a fuel pipe 54 extends from a fuel tank 53 and an injection valve 55 is connected to the fuel pipe 54. A pump axis 56 of the fuel tank 53 is disposed such that the angle 9 thereof with respect to the mono-backbone frame 12 which is in an inclined state is 70 to 90°, that is, approximately perpendicular with respect to the mono-backbone frame 12. As can be seen apparently from FIG. 3, the fuel tank 2 6 can be made compact in terms of the height. [0032] The air cleaner 27 includes an element 58 in a cleaner case 57 and includes a clean side drain discharge pipe 59 and a dirty side drain discharge pipe 61. Reference numeral 60 denotes a liquid level detection sensor float. The fuel tank 26 is attached by means of tank supporting brackets BKl, BK2 and bolts Bl, B2 provided on the mono-backbone frame 12. The engine 31 includes a crankshaft 63, a connecting rod 64, a piston 65, a cylinder 29, and a cylinder head 66 on a crankcase 62, and includes a camshaft 67, rocker arms 68, intake valves 69, and exhaust valves 71 on the cylinder head 66. Reference numeral 72 denotes a self-starting motor, and 73 a battery. [0034] Reference numeral 105 denotes a main gear, and 106 a counter gear. The main gear 105 is disposed on a line which passes the counter gear 106 and the crankshaft 63. Meanwhile, reference numeral 107 denotes a shift drum and 108 a weight reducing hole formed in the pivot plate 13R (13L). [0035] In particular, the fuel tank 26 is disposed on the mono-backbone frame 12 in the proximity of the cylinder 29 (cylinder head 66). This makes it possible to dispose the fuel tank 26 on the cylinder 29 (cylinder head 66), and the fuel pipe 54 can be made shorter. If the length of the fuel pipe 54 decreases, then the supply cost of the fuel pipe 54 can be reduced and also the mounting cost of the fuel pipe 54 can be reduced. FIG. 4 is a view as viewed in the direction of an arrow mark 4 of FIG. 3, and the fuel tank 26 has a shape approximate to that of the lungs of a human being. Further, the fuel tank 53 is disposed on one side of the mono-backbone frame 12. In particular, since the fuel tank 53 is disposed bypassing the mono-backbone frame 12, increase of the heightwise dimension of the fuel tank 2 6 can be suppressed and the fuel tank 26 can be made compact in terms of the height. [0037] Now, details of the exhaust pipe, catalyzer and muffler are described. FIG. 5 is an enlarged view of essential part of the motorcycle according to the present invention. The cross portion 37 which interconnects the exhaust pipe front portion 36 and the exhaust pipe rear portion 38 is disposed forwardly of the rear wheel 17 indicated by a phantom line below the rear swing arms 15L, 15R immediately rearwardly (rightwardly in FIG. 5) of the pivot plates 13L, 13R, [0038] First, the muffler 3 9 is disposed rearwardly of an accommodation box 47 disposed below the seat 19. The accommodation box 47 and the muffler 39 are disposed in the forward and backward direction of the vehicle body-below the seat 19, and effective utilization of the space below the seat 19 can be anticipated. Since the muffler 39 is disposed rearwardly, the muffler 39 can be spaced away from the engine 31 and the pipe length of the exhaust pipe 3 5 can be increased. [0039] Meanwhile, the muffler 39 includes a heat insulating plate 74 extending into a space between the muffler 39 and the seat 19 and between the muffler 39 and the accommodation box 47. Heat which tends to flow from the muffler 3 9 toward the seat 19 or the accommodation box 47 can be intercepted by the heat insulating plate 74, and a temperature rise of the seat 19 or the accommodation box 47 can be suppressed. [0040] Further, the fuel tank 26 is disposed so as to cover over an upper portion of the air cleaner 27 in such a manner as to sandwich the upper portion of the air cleaner 27 from the left and the right (in FIG. 5, from this side and that side) . Since the fuel tank 26 and the air cleaner 27 partly overlap with each other in the heightwise direction in addition to the fact that the air cleaner 27 is disposed below the fuel tank 2 6 and the cylinder 29 (cylinder head 66) is disposed below the air cleaner 27, the fuel pipe (reference numeral 54 in FIG. 3) which interconnects the fuel tank 2 6 and the cylinder head 66 can be made comparatively short. [0041] Further, the cross portion 37 is characterized in that it is disposed at a position higher than the main stand 43 during traveling of the motorcycle. Although earth and stone leap up from the road surface during traveling of the motorcycle, the cross portion 3 7 including the catalyzer is guarded by the main stand 43. In other words, a protector for protecting the catalyzer can be omitted. [0042] FIG. 6 is a sectional view taken along line 6-6 of FIG. 5, which corresponds to a view as viewed from rearwardly of the vehicle body. The cross portion 3 7 is formed from a box 75 of a polygonal cross section (in this example, pentagonal), and contains a horizontally elongated tubular catalyzer 76 whose length L is greater than the outer diameter D thereof. Exhaust gas exhausted from the exhaust pipe front portion 3 6 flows as indicated by an arrow mark (1), another arrow mark (2) and comes to the exhaust pipe rear portion 38. The exhaust pipe rear portion 38 extends between the left and right rear swing arms 15L, 15R and on the right side of the mono-suspension 45 to the muffler 39. Reference character PI denotes the joining position of the box 75 to the exhaust pipe front portion 36, and P2 the joining position of the box 75 to the exhaust pipe rear portion 38. [0043] Further, reference character CP denotes a joint for coupling two divisional pieces of the exhaust pipe rear portion 38. A rear portion of the exhaust pipe passes in the proximity of the rear suspension and is difficult to assemble. By forming this portion so as to be separable at the joint CP, the assembly operation can be simplified. A plurality of joints CP may be provided. [0044] The muffler 3 9 is a box member whose bottom portion 77 and ceiling portion 78 are formed considerably greater than the height of walls 79, 79 and which has a recessed portion 81 provided at the bottom portion 77 so as to be recessed upwardly. An upper end of the rear wheel 17 indicated by an imaginary line can be accommodated in the recessed portion 81. In other words, the muffler 3 9 is characterized in that it has a horizontally elongated shape which is further elongated in a vehicle widthwise direction. Since the muffler 39 has a horizontally elongated shape, the volume can be increased while preventing contact of the muffler 3 9 with the rear wheel. It is to be noted that the bottom portion 77 may have a shape same as that of the ceiling portion 78 with the recessed portion 81 omitted. Even this can increase the volume while contact of the bottom portion 77 with the rear wheel 17 is prevented. [0045] Further, the tubular catalyzer 76 is disposed in such a manner as to extend in a vehicle widthwise direction as seen in FIG. 6. As a result, in FIG. 5, the tubular catalyzer 76 can be disposed in a small space between the pivot shaft 14 and the rear wheel 17. Since the tubular catalyzer 76 is disposed in a vehicle widthwise direction, the tubular catalyzer 76 of a required length can be disposed and the purification performance can be raised without being influenced by the forward and backward direction of the vehicle body. [0046] Furthermore, since the exhaust pipe 3 5 includes the cross portion 37 extending in a vehicle widthwise direction and the catalyzer is disposed in the cross portion 37, both of the cross portion 37 and the tubular catalyzer 76 extend in the vehicle widthwise direction. Consequently, the flow of exhaust gas becomes smooth as indicated by arrow marks (1), (2) in FIG. 6 and the flow path resistance to the exhaust gas can be reduced. [0047] In FIG. 6, the exhaust pipe rear portion 3 8 for introducing exhaust gas from the cross portion 3 7 is disposed on the inner side of the seat rail 18R. The seat rail IBR exhibits a guarding action of preventing approach to the exhaust pipe rear portion 38. The heat insulating protector can be omitted. [0048] As apparently seen from FIGS. 5 and 6, the exhaust pipe rear portion 3 8 passes a space 84 (refer to FIG. 5) defined by the pivot shaft 14, the left and right rear swing arms 15L, 15R, and a cross member 83. Since the exhaust pipe rear portion 3 8 passes through the space 84, effective utilization of the space 84 can be anticipated. [0049] Further, referring to FIG. 5, the cross member 83 extends between the left and right rear swing arms 15L, 15R, and the mono-suspension 45 is connected at a lower portion thereof to the cross member 83. As a result, a space is formed below the rear swing arms 15L, 15R. Accordingly, it is possible to dispose the cross portion 3 7 of the exhaust pipe and the tubular catalyzer 76 below and in the proximity of the rear swing arms 15L, 15R, and the layout efficiency can be raised. [0050] Now, an attaching structure of the mono-suspension 4 5 is described. FIG, 7 is a perspective view showing an attaching structure for the mono-suspension and shows a body frame structure. In the body frame structure, the mono-backbone frame 12 extends rearwardly downwards from the head pipe 11, and the pivot plates 13L, 13R are attached to a rear end of the mono-backbone frame 12. The pivot shaft 14 is attached to the pivot plates 13L, 13R, and the rear swing arms 15L, 15R are attached to the pivot shaft 14. Further, the left and right seat rails 18L, IBR extend rearwardly upwards from an intermediate portion of the mono-backbone frame 12 and are supported by the rail stays 21L, 21R. [0051] It is to be noted that reference characters CMl and CM2 denote cross members held between the pivot plates 13L, 13R, and a cross member 85 extends between the left and right seat rails 18L, 18R to prepare for attachment of the mono-suspension 45. [0052] FIG. 8 is a side elevational view showing an attaching structure for the mono-suspension. The mono-suspension 45 is connected at a lower end thereof to the cross member 83 by means of a pin 87 through the cross member 85. Since the cross member 83 exhibits a horizontally elongated rectangular cross section, a lower bracket 86 can be attached readily to the cross member 83. [0053] Meanwhile, an upper bracket 90 by which an upper end of the mono-suspension 45 is attached to the vehicle body frame side has a rather complicated shape. In particular, the upper bracket 90 is a pressed article including flange portions 91L, 91R (refer also to FIG. 7) and a web portion 92 interconnecting front ends of the flange portions 91L, 91R. A large cutaway portion 93 is provided on a rear edge of the flange portions 91L, 91R while a pinhole (into which a support shaft 97 is fitted) is provided at an upper corner portion. Further, a small cutaway portion 95 is provided at a portion at which an upper side and the web portion 92 intersect with each other. [0054] Then, a lower edge of the flange portions 91L, 91R and a lower edge of the web portion 92 are welded to the mono-backbone frame 12, and the cutaway portion 95 is fitted with the cross member 85. In this state, the cutaway portion 95 is welded to the cross member 85 to attach the cutaway portion 95 to the cross member 85. The upper bracket 90 plays a role of a reinforcing member which interconnects the cross member 8 5 and the mono-backbone frame 12. Reference character w denotes a weld bead, and the rigidity and the connection strength can be raised by welding at a plurality of locations. [0055] The seat 19 is connected to the vehicle body frame side by a hinge pin 99 through a connecting member 98. Although the accommodation box 4 7 disposed below the seat 19 may be open at the top thereof, an inner lid 101 is provided in order to prevent invasion of dust or rainwater when the seat 19 is open. Further, the inner lid 101 is connected at an end thereof to the hinge pin 99. In particular, the hinge pin 99 for the seat 19 and the hinge pin 99 for the inner lid 101 are used commonly. Reduction of the number of parts (hinges) can be anticipated thereby. [0056] The inner lid 101 moves upwardly and downwardly around the hinge pin 99. In order to prevent such inadvertent upward movement of the inner lid 101, the inner lid 101 may be suppressed by a seal member 102 provided normally for the seat 19. In addition, a protrusion 103 may be provided downwardly as indicated by a phantom line at a location remote from the hinge pin 99 so as to suppress the inner lid 101. [0057] As a result, the upper bracket 90 has a width W which is very small as seen in FIG. 7. FIG. 9 is a sectional view talcen along line 9-9 of FIG. 8 and shows the mono-suspension 45 is mounted on the lower bracket 86 provided at the center (or substantially at the center) of the cross member 83 extending between the rear swing arms 15L, 15R and the upper bracket 90 provided at the center (or substantially at the center) of the cross member 85 extending between the seat rails 18L, 18R. It can be recognized that the width W of the upper bracket 90 is sufficiently small. since the upper bracket 90 is slim, the following advantages are provided. A battery 73 can be disposed alongside the mono-suspension 45, particularly on the right side of the mono-suspension 45. Further, a lower portion 96 of the accommodation box 47 can be inserted to a location alongside the mono-suspension 45, particularly, on the left side of the mono-suspension 45. In other words, since the upper bracket 90 is compact, the spaces on the opposite left and right sides of the mono-suspension 45 can be utilized effectively as arrangement spaces for accessories or the like. [0059] Further, as shown in FIG. 8, the support shaft 97 for attaching the upper end portion 94 of the mono-suspension 45 to the upper bracket 90 is disposed just above (including substantially just above) the pivot shaft 14. As a result, the upper bracket 90 is disposed at a rather forward position of the vehicle body, and the space rearwardly of the mono-suspension 45 can be expanded. Thus, the increased space can be utilized effectively. Further, as the upper bracket 90 is disposed at a position rather forwardly of the vehicle body, the seat rails 18L, 18R geometrically approach the mono-backbone frame 12, and the height of the upper bracket 90 decreases and miniaturization and reduction in weight can be achieved. Therefore, the upper bracket 90 is displaced to a front portion of the vehicle body as far as possible. [0061] It is to be noted that, in claim 1, only it is necessary for the catalyzer to be disposed so as to extend in a vehicle widthwise direction, but there is no necessary to cause the exhaust pipe to extend in a vehicle widthwise direction. [0062] The present invention is suitable for a small-sized motorcycle. [Brief Description of the Drawings] [0063] [FIG. 1] FIG, 1 is a side elevational view of a motorcycle according to the present invention. [FIG. 2] FIG. 2 is a top plan view of essential part of the motorcycle according to the present invention. [FIG. 3] FIG. 3 is a side elevational sectional view of essential part of the motorcycle according to the present invention. [FIG. 4] FIG. 4 is a view as viewed in a direction indicated by an arrow mark 4 of FIG. 3. [FIG. 5] FIG. 5 is an enlarged view of essential part of the motorcycle according to the present invention. [FIG. 6] FIG. 6 is a sectional view taken along line 6-6 of FIG. 5. [FIG. 7] FIG. 7 is a perspective view showing an attaching structure for a mono-suspension. [FIG. 8] FIG. 8 is a side elevational view showing the attaching structure for the mono-suspension. [FIG. 9] FIG. 9 is a sectional view taken along line 9-9 of FIG. 8. [Description of Reference Symbols] 10 ... motorcycle, 14 ... pivot shaft, 15L, 15R ... rear swing arm, 17 ... rear wheel, 18L, 18R ... seat rail, 31 ... engine, 35 ... exhaust pipe, 36 ... exhaust pipe front portion, 37 ... cross portion, 38 ... exhaust pipe rear portion, 76 ... catalyzer, 83 ... cross member, 84 ... space, CP ... joint, LL ... vehicle body center line. [Name of Document] Claims [Claim 1] A motorcycle wherein a rear swing arm is attached for upward and downward swinging movement at a rear portion of a vehicle body frame through a pivot shaft and a rear wheel is provided at a rear portion of said swing arm while an engine is disposed forwardly of said pivot shaft and an exhaust pipe from said engine extends rearwardly, characterized in that a catalyzer for purifying the exhaust gas is built in said exhaust pipe and has a tubular shape which has a length greater than the outer diameter thereof, and the tubular catalyzer is disposed between said pivot shaft and said rear wheel in such a manner as to extend in a vehicle widthwise direction. [Claim 2] The motorcycle according to claim 1, characterized in that said exhaust pipe includes a cross portion which extends in the vehicle widthwise direction, and said catalyzer is disposed in said cross portion. [Claim 3] The motorcycle according to claim 2, characterized in that a rear portion of said exhaust pipe which introduces the exhaust gas from said cross portion is disposed on the inner side of a seat rail as viewed in plan. [Claim 4] The motorcycle according to claim 2, characterized in that said rear swing arm is formed from left and right arms and a cross member extends between said arms while a rear suspension is connected at a lower portion thereof to said cross member, and a rear portion of said exhaust pipe which introduces the exhaust gas from said cross portion passes a space defined by said pivot shaft, left and right arms, and cross member. [Claim 5] The motorcycle according to claim 2, characterized in that a front portion of said exhaust pipe which introduces the exhaust gas from a cylinder to said cross section is disposed on the left side of the vehicle body center line as viewed in plan and said cross portion is disposed substantially at the vehicle body center as viewed in plan while a rear portion of said exhaust pipe is disposed on the right side of the vehicle body center line as viewed in plan, [Claim 6] The motorcycle according to claim 2, characterized in that said cross portion is disposed at a position higher than a main stand when said motorcycle travels. [Claim 7] The motorcycle according to claim 4 or 5, characterized in that said rear portion of said exhaust pipe is formed so as to be capable of being separated intermediately using at least one joint.

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2479-CHE-2007 AMENDED PAGES OF SPECIFICATION 03-11-2011.pdf

2479-CHE-2007 AMENDED CLAIMS 03-11-2011.pdf

2479-CHE-2007 FORM-3 03-11-2011.pdf

2479-CHE-2007 OTHER PATENT DOCUMENT 03-11-2011.pdf

2479-CHE-2007 CORRESPONDENCE PO.pdf

2479-CHE-2007 EXAMINAITON REPORT REPLY RECEIVED 03-11-2011.pdf

2479-che-2007-abstract.pdf

2479-che-2007-claims.pdf

2479-che-2007-correspondnece-others.pdf

2479-che-2007-description(complete).pdf

2479-che-2007-drawings.pdf

2479-che-2007-form 1.pdf

2479-che-2007-form 18.pdf

2479-che-2007-form 26.pdf

2479-che-2007-form 3.pdf

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2479-che-2007-other document.pdf

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