Vehicle and muffler protector unit

Abstract

 To provide a vehicle and a muffler protector unit that can sufficiently protect a muffler body and also can improve the cooling performance of the muffler body. At least a portion of a rear end surface 24a of a tubular muffler body 24 positioned on one side of a vehicle body is covered by an end cap 53. At least a portion of a right side surface 24c of the muffler body 24 is covered by a first protector 51 positioned on an opposite side of the muffler body relative to the vehicle body frame. A second protector 52 is positioned in the rear of the first protector 51 so as to be spaced apart therefrom in a longitudinal direction X1 of the muffler body 24. The second protector 52 covers the right side surface 24c of the muffler body 24 and uncovers a top area 24d of the muffler body 24. The second protector 52 is narrower than the first protector 51 in a width direction Y1 normal to the longitudinal direction X1 of the muffler body 24 in a lateral side view.

Description

Field

[0001] This invention relates to a vehicle and a muffler protector unit. Background

[0002] A vehicle such as a motorcycle having an engine working as a power source is provided with a muffler (also known as a silencer) into which exhaust gases are introduced from an engine (for example, see JP-A-2006-17046). Such a vehicle can have a protector which protects a muffler body. The protector is placed to cover a lateral side surface and so forth of the muffler body. Summary

[0003] However, conventional muffler protectors have a construction that entirely covers one lateral side surface of the muffler body, as shown in JP-A-2006-17046. Therefore, heat radiation to the lateral side surface of the muffler body is difficult to be made, although the muffler body is sufficiently protected. Accordingly, there is room for improvement in the cooling performance of a muffler.

[0004] An object of aspects of this invention is to provide a vehicle that can sufficiently protect a muffler body and also can improve the cooling performance of the muffler body.

[0005] Another object of aspects of this invention is to provide a muffler protector unit that can sufficiently protect a muffler body and also can improve the cooling performance of the muffler body.

[0006] Viewed from one aspect, the present invention provides a vehicle including a tubular muffler body positioned on one side of a vehicle body; an end cap covering at least a portion of a rear end surface of the muffler body; a first protector covering at least a portion of a lateral side surface of the muffler body and positioned on an opposite side of the muffler body relative to the vehicle body; and a second protector positioned in the rear of the first protector so as to be spaced apart therefrom in a longitudinal direction of the muffler body. The second protector covers the lateral side surface of the muffler body, uncovers a top area of the muffler body, and is narrower than the first protector in a width direction normal to the longitudinal direction of the muffler body in a lateral side view.

[0007] According to this arrangement, the first protector and the second protector are positioned to be spaced apart from each other in the longitudinal direction of the muffler body. Thereby, a large area of the lateral side surface of the muffler body can be protected, and hence the muffler body can be sufficiently protected.

[0008] Also, the second protector uncovers the top area of the muffler body, and is narrower than the first protector in a lateral side view. Thereby, heat can be sufficiently radiated to the top area and the lateral side surface of the muffler body, and hence the heat radiation performance of the muffler body can be sufficiently kept. Consequently, the cooling performance of the muffler body can be improved.

Brief Description of the Drawings

[0009] For a better understanding of the invention and to show how the same may be carried into effect reference is now made by way of example to the accompanying drawings in which:

FIG. 1 is a schematic, right side view showing the entire construction of a motorcycle having a muffler protector unit configured in accordance with an embodiment;

FIG. 2 is a right side view of a muffler and the muffler protector unit;

FIG. 3 is a plan view of the muffler;

FIG. 4 is a plan view showing a portion of the muffler in cross section;

FIG. 5 is a partially enlarged view of FIG. 4;

FIG. 6 is a plan view of a major part of the motorcycle;

FIG. 7 is an enlarged view of a major part of FIG. 2;

FIG. 8 is a side view viewed along the arrow VIII of FIG. 7;

FIG. 9 is a cross sectional view taken along the line IX-IX of FIG. 8;

FIG. 10 is a cross sectional view taken along the line X-X of FIG. 7;

FIG. 11 is a cross sectional view taken along the line XI-XI of FIG. 7;

FIG. 12 is a cross sectional view of a major part taken along the line XII-XII of FIG. 7;

FIG. 13 is a cross sectional view taken along the line XIII-XIII of FIG. 7;

FIG. 14 is a cross sectional view of a major part taken along the line XIV-XIV of FIG. 2;

FIG. 15 is a cross sectional view of a major part taken along the line XV-XV of FIG. 2; and

FIG. 16 is a right side view showing a construction of a muffler protector unit configured in accordance with another embodiment.

[0010] While the invention is susceptible to various modifications and alternative forms, specific embodiments are shown by way of example in the drawings and are herein described in detail. It should be understood, however, that the drawings and detailed description are not intended to limit the invention to the particular form disclosed, but on the contrary, the invention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the present invention as defined in the appended claims.

Specific Description

[0011] With reference to drawings, embodiments of this invention will be specifically described below.

[0012] In the embodiments described below, a motorcycle is described as an example of vehicles. This invention, however, can be applied to other straddle type vehicles such as a three- or four-wheeled buggy (ATV: all terrain vehicle) and further to other type vehicles having a muffler.

[0013] FIG. 1 is a schematic, right side view showing the entire construction of a motorcycle 1, which is one of vehicles having a muffler protector unit configured in accordance with an embodiment. As used herein, references to a "front to rear direction," a "right to left direction" and a "top to bottom direction" mean respective directions on a basis of front and rear portions, right and left portions, and top and bottom portions of a motorcycle 1 in normal use on a horizontal surface.

[0014] The motorcycle 1 has a vehicle body frame 2 as a vehicle body, a front fork 3 positioned in front of the vehicle body frame 2, a front wheel 4 coupled with the front fork 3, a rear arm 5 supported by the vehicle body frame 2, and a rear wheel 6 coupled with the rear arm 5. The motorcycle 1 also has an engine 7 mounted to the vehicle body frame 2, a muffler 8 positioned on a lateral side (for example, on a right side) of the vehicle frame 2, and a muffler protector unit 9 attached to the muffler 8. As used herein, the term "muffler" when describing a vehicle exhaust component or assembly is interchangeable with the term "silencer" in the same contexts.

[0015] The vehicle body frame 2 includes a main frame 10, a seat rail 12 and a seat stay 13. The main frame 10 supports the engine 7, the front fork 3 and the rear arm 5. The seat rail 12 is coupled with the main frame 10 and supports the seat 11. The seat stay 13 supports the seat 11, together with the seat rail 12.

[0016] The main frame 10 includes a head pipe 14, a right and left pair of down tubes 15, 15 (only one down tube 15 is shown in FIG. 1), and a right and left pair of tank rails 16, 16 (only one tank rail 16 is shown in FIG. 1). The head pipe 14 is placed at a front end of the main frame 10 and supports the front fork 3 for rightward and leftward steering movements. The pair of down tubes 15, 15 extend obliquely downward while expanding outward from the head pipe 14 in the vehicle width direction, and then extend rearward of the vehicle body. The pair of tank rails 16 extend obliquely downward while expanding outward from a top end portion of the head pipe 14 in the vehicle width direction, and then are coupled with rear end portions of the right and left down tubes 15, 15, respectively.

[0017] The front fork 3 extends in slant relative to the ground with a preset caster angle. A bottom end portion of the front fork 3 supports the front wheel 4 for rotation via an axle 17. A steering handle bar 18 is fixed to a top end portion of the front fork 3.

[0018] Right and left rear arm brackets 19, 19 (only one rear arm bracket 19 is shown in FIG. 1) are positioned at a rear end of the main frame 10. The rear arm 5 is supported by those rear arm brackets 19, 19 for up and down swing movement. A rear end portion of the rear arm 5 supports the rear wheel for rotation via an axle 20. Rear suspensions (not shown) are arranged between the rear arm 5 and the main frame 10.

[0019] The seat 11 extends front to rear. A portion of the seat 11 overlaps with the rear wheel 6 in the top to bottom direction.

[0020] A cradle is formed with the tank rails 16 and the down tubes 15. An engine 7 is mounted in the cradle. The engine 7 is, for example, a water-cooled, four stroke and single cylinder engine, and includes a crankcase 21 holding a crankshaft (not shown) and a cylinder block 22 coupled with the crankcase 21.

[0021] The output power of the crankshaft of the engine is transmitted to the rear wheel 6 through a transmission mechanism, a chain and so forth which are not shown. Thereby, the rear wheel 6 is driven to rotate.

[0022] The muffler 8 is connected to an exhaust port (not shown) opening at a front wall of the cylinder block 22 of the engine 7.

[0023] The muffler 8 purifies exhaust gases of the engine 7 and reduces exhaust noises of the engine 7. The muffler 8 is supported by a bracket (not shown) or the like fixed to the main frame 10. The muffler 8 has a shape that extends downward relative to the cylinder block 22 and then extends rearward. A rear end portion of the muffler 8 inclines obliquely in such a manner that a part thereof is positioned higher than another part as the part is positioned rearward more than the another part.

[0024] FIG. 2 is a right side view of the muffler 8 and the muffler protector unit 9. FIG. 3 is a plan view of the muffler 8. FIG. 4 is a plan view showing a portion of the muffler 8 in cross section. Additionally, even when referring to FIGs. 2-4, the phrases such as front to rear direction, right to left direction and top to bottom direction will be used on a basis of the position of the muffler 8 in which the muffler 8 is mounted onto the right side of the vehicle body frame 2.

[0025] With reference to FIGs. 2 and 3, the muffler 8 has a receiving conduit 23 which receives exhaust gases from the engine 7, and a tubular muffler body 24 coupled with the receiving conduit 23 and holding a portion of the receiving conduit 23.

[0026] The receiving conduit 23 is provided to convey the exhaust gases from the engine 7 to the interior of the muffler body 24. A shape of the receiving conduit 23 in cross section is generally circularly configured. An inlet end portion 23a of the receiving conduit 23 can be connected to the cylinder block 22 (see FIG. 1) of the engine 7. A flange section 25 to be coupled with the cylinder block 22 is provided in an outer circumferential surface of the inlet end portion 23a.

[0027] The receiving conduit 23 extends obliquely downward forward from the inlet end portion 23a and then extends rearward. A middle portion 23b of the receiving conduit 23 has an opening cross sectional area being wider than that of the inlet end portion 23a. A first catalyst 26 and a second catalyst 27 are fixed to the interior of the middle portion 23b. The first catalyst 26 and the second catalyst 27 are provided to individually purify the exhaust gases passing through the interior of the receiving conduit 23. The first and second catalysts 26, 27 are lined to be spaced apart from each other in the front to rear direction. A secondary air delivery conduit 28 is connected to a location between the first catalyst 26 and the second catalyst 27 in the middle portion 23b of the receiving conduit 23. A rear end portion 23c of the receiving conduit 23 has an opening cross sectional area being narrower than that of the middle portion 23b, and extends generally straightly.

[0028] The muffler body 24 is provided to reduce the exhaust noises of the engine 7, and is positioned on the right side of the rear wheel 6 (see FIG. 1). With reference to FIGs. 3 and 4, the muffler body 24 is formed using a sheet metal member, and has an outer tube 31; an inner tube 32 held within the outer tube 31; first and second rear end walls 33, 34; a partition 35; a communication conduit 36; and a tail conduit 37. The outer tube 31 and the inner tube 32 together form a dual tube. The first and second rear end walls 33, 34 are positioned at a rear end portion of the dual tube.

[0029] The outer tube 31 has a shape in cross section configured generally circularly, and holds the middle portion 23b and the rear end portion 23c (outlet end portion) of the receiving conduit 23. The outer tube 31 includes a first section 38, a second section 39 and a third section 40 which are lined from the front side to the rear side. The first section 38 extends straightly. An inner circumferential surface of a front end portion of the first section 38 is fixed by weld to an outer circumferential surface of the middle portion 23b of the receiving conduit 23.

[0030] The first section 38 and the second section 39 are unitarily formed using, for example, a single material. The second section 39 extends obliquely upward relative to a rear end portion of the first section 38. The farther the opening cross sectional area of the second section 39 is spaced apart from the first section 38, the wider the area is. The second section 39 holds a part of the middle portion 23b of the receiving conduit 23, and surrounds the first catalyst 26 and a portion of the second catalyst 27. The second section 39 has a through-hole 39a. The secondary air delivery conduit 28 projects from the through-hole 39a.

[0031] With reference to FIGs. 2 and 4, the third section 40 is formed using a material separately provided from the second section 39. The third section 40 extends generally parallel to a rear end portion of the second section 39, and extends upward in such a manner that a part of the third section is positioned higher than another part thereof as the part is positioned rearward more than the another part. The third section 40 holds another part of the middle portion 23b of the receiving conduit 23 and the rear end portion 23c, and further holds a portion of the second catalyst 27. A longitudinal direction of the third section 40 will be used to describe a longitudinal direction X1 of the muffler body 24 (occasionally, simply called "longitudinal direction X1") below.

[0032] FIG. 5 is a partially enlarged view of FIG. 4. The inner tube 32 extends from a middle portion 40b of the third section 40 of the outer tube 31 to a rear end portion 40c thereof in the longitudinal direction X1. A portion of an outer circumferential surface of a front end portion 32a of the inner tube 32 extends along an inner circumferential surface of the third section 40, and is fixed to the inner circumferential surface. An outer circumferential surface of a middle portion 32b of the inner tube 32 is spaced apart from the inner circumferential surface of the third section 40 with a preset distance. A ring-shaped member 41 is inserted into a space between a portion of the outer circumferential surface of the middle portion 32b of the inner tube 32 and a portion of the inner circumferential surface of the middle portion 40b of the third section 40. Thereby, the space between the outer circumferential surface of the middle portion 32b of the inner tube 32 and the inner circumferential surface of the middle portion 40b of the third section 40 is maintained. The rear end portion 32c of the inner tube 32 is widened relative to the middle portion 32b. The outer circumferential surface of the rear end portion 32c of the inner tube 32 is fixed to the inner circumferential surface of the rear end portion 31c of the outer tube 31 by weld. The inner tube 32 surrounds the rear end portion 23c of the receiving conduit 23.

[0033] The first rear end wall 33 is a cup-like member placed at the respective rear end portions 31 c, 32c of the outer tube 31 and the inner tube 32, and covers most of the rear end portions 31c, 32c. The first rear end wall 33 has a ring-shaped flange portion 33a protruding forward from an outer circumferential end thereof in the longitudinal direction X1. An outer circumferential surface of the flange portion 33a is fixed to an inner circumferential surface of the rear end portion 32c of the inner tube 32 by weld. A rear outer surface of the first rear end wall 33 defines a rear end surface 24a of the muffler body 24.

[0034] The second rear end wall 34 is a cup-like member placed in front of the first rear end wall 33. A flange portion 34a protruding forward from an outer circumferential end of the second rear end wall 34 in the longitudinal direction X1 is provided. An outer circumferential surface of the flange portion 34a is fixed to an inner circumferential surface of the flange portion 33a of the first rear end wall 33 by weld.

[0035] The partition 35 is provided to divide the space inside of the muffler body 24. The partition 35 is placed out of the middle portion 32b of the inner tube 32 and is positioned close to the front end portion 32a of the inner tube 32. An outer circumferential surface of the partition 35 is fixed to an inner circumferential surface of the middle portion 32b of the inner tube 32 by weld. Also, the partition 35 has an insertion aperture 35a into which the receiving conduit 23 is inserted, an insertion aperture 35b into which the communication conduit 36 is inserted, and an insertion aperture 35c into which the tail conduit 37 is inserted.

[0036] Thus, the muffler body 24 is provided with a first expansion chamber 45 defined by the inner tube 32, the partition 35 and the rear end wall 34. Also, as shown in FIG. 4, the muffler body 24 is provided with a second expansion chamber 46 defined by the outer tube 31, the inner tube 32 and the partition 35.

[0037] With reference to FIG. 5, the first expansion chamber 45 is defined at a position closer to the rear end portion 24b of the muffler body 24. The rear end portion 23c of the receiving conduit 23 opens to the first expansion chamber 45. Thereby, the exhaust gases passing through the receiving conduit 23 are introduced into the first expansion chamber 45. The exhaust gases introduced into the first expansion chamber 45 from the rear end portion 23c of the receiving conduit 23 impinge upon the second rear end wall 34 while distending, and expand in the interior of the first expansion chamber 45.

[0038] The communication conduit 36 is inserted into the insertion aperture 35b of the partition 35 as described above. Thereby, the first expansion chamber 45 and the second expansion chamber 46 are in communication with each other through the communication conduit 36. The exhaust gases introduced into the first expansion chamber 45 are introduced into the second expansion chamber 46 through the communication conduit 36. The second expansion chamber 46 is defined between the engine 7 (see FIG. 1) and the first expansion chamber 45 in the front to rear direction of the vehicle body frame 2. That is, the second expansion chamber 46 is positioned in the rear of the engine 7 and is defined in front of the first expansion chamber 45. The exhaust gases passing through the communication conduit 36 and introduced into the second expansion chamber 46 expand within the second expansion chamber 46.

[0039] The tail conduit 37 extends to penetrate the inner tube 32 in the longitudinal direction X1. The tail conduit 37 is inserted into the insertion aperture 35c of the partition 35 and an insertion aperture 33b defined in the first rear end wall 33. A front end portion 37a of the tail conduit 37 opens to the second expansion chamber 46. A rear end portion 37c of the tail conduit 37 opens at a location in the rear of the muffler body 24. Thereby, the exhaust gases in the second expansion chamber 46 are discharged outside of the muffler body 24 through the tail conduit 37.

[0040] With reference to FIGs. 3 and 4, the first catalyst 26 and the second catalyst 27 can have the highest temperature in the muffler body 24.

[0041] FIG. 6 is a plan view of the major part of the motorcycle 1. With reference to FIGs. 2 and 6, the muffler protector unit 9 is provided to protect the muffler body 24, and is placed to cover a portion of the muffler body 24. The muffler protector unit 9 has a first protector 51, a second protector 52 spaced apart rearward from the first protector 51, and an end cap 53 positioned in the rear of the second protector 52.

[0042] The first protector 51 covers at least a portion of a right side surface 24c of the muffler body 24. The first protector 51 has a first protector structural member 54 formed with a unitary molding piece made of a synthetic resin including polyamide. The first protector 51 is positioned on an opposite side of the muffler body 24 relative to the vehicle body frame 2, i.e., on the right side of the muffler body 24. The first protector 51 covers a first area 55 of the muffler body 24. The first area 55 includes a front side area 56 and a rear side area 57. The front side area 56 is the area close to a top end of the muffler body right side surface 24c in the second section 39 of the outer tube 31. The rear side area 57 is the area close to a top end of the muffler body right side surface 24c on a front end side of the third section 40 of the outer tube 31.

[0043] The first protector 51 includes a front side section 58 covering the front side area 56 and a rear side section 59 positioned in the rear of the front side section 58 and covering the rear side area 57. The front side section 58 is formed in such a manner that a part thereof is wider in width than another part as the part is positioned rearward more than the another part in the longitudinal direction X1. The width in this regard is a dimension in a width direction Y1 normal to the longitudinal direction X1. The width direction Y1 is the direction that is normal to the longitudinal direction X1 when the muffler body 24 is viewed from a right side location. Because the front side section 58 is positioned on the right side of the first catalyst 26, the front side section 58 can sufficiently protect the circumference of the first catalyst 26 that is heated by the exhaust gases to have a high temperature.

[0044] The rear side section 59 extends generally straightly in the longitudinal direction X1. The rear side section 59 includes a constant width portion 61 whose width (length in the width direction Y1) is generally fixed; and a tapered portion 62 positioned in the rear of the constant width portion 61 and formed in such a manner that a part thereof is narrowed in width than another part as the part is positioned rearward more than the another part in the longitudinal direction X1.

[0045] The width of the tapered portion 62 changes in such a manner that a part of a lower end hem of the tapered portion 62 is positioned higher than another part thereof as the part is positioned rearward more than the another part in the longitudinal direction X1. The rear side section 59 has through-holes 59a for radiating heat, in the area extending from the constant width portion 61 to the tapered portion 62. The through-holes 59a are spaced apart in the longitudinal direction X1 to be formed in a plurality of portions (three portions in this embodiment). Each through-hole 59a elongates in the longitudinal direction X1 and opens obliquely upward rightward.

[0046] The second protector structural member 63 structuring the second protector 52 and the end cap structural member 64 structuring the end cap 53 are unitarily formed with each other by a single synthetic resin material 65. The synthetic resin material 65 is the same as the material of the first protector 51.

[0047] FIG. 7 is an enlarged view of the major part of FIG. 2. FIG. 8 is a side view viewed along the arrow VIII of FIG. 7. FIG. 9 is a cross sectional view taken along the line IX-IX of FIG. 8. With reference to FIGs. 7, 8 and 9, the end cap 53 is provided to cover at least a portion of the rear end surface 24a of the muffler body 24. The end cap 53 covers, for example, a portion except for a center part from which the tail pipe 37 projects and surrounding part thereof in the rear end surface 24a. The end cap 53 is configured to be a ring-like shape. More specifically, the end cap 53 includes a groove shaped portion 66 whose cross section intersects in a circumferential direction defines a groove, and a skirt portion 67 placed in an outer circumference of the groove shaped portion 66.

[0048] The groove shaped portion 66 includes an inner wall 68 surrounding the rear end portion 37c of the tail conduit 37, an outer wall 69 surrounding the inner wall 68, and a bottom wall 70 connecting respective front end portions of both the inner wall 68 and the outer wall 69. The skirt portion 67 extends forward from a rear end portion of the outer wall 69. More in detail, the skirt portion 67 has a base end side portion connected to the outer wall 69 and a distal end portion connected to a front side of the base end side portion. The base end side portion is tapered so that a part thereof is widened in diameter than another part as the part is positioned forward more than the another part. The distal end portion has a generally fixed diameter and is positioned adjacent to the rear end surface 24a of the muffler body 24.

[0049] The second protector 52 is provided to cover the portion of the right side surface 24c of the muffler body 24 and uncover a top area 24d of the muffler body 24. The top area 24d is an area close to the rear end portion 24b of the muffler body 24. The top area 24d is an area located above the first expansion chamber 45.

[0050] The second protector 52 extends forward from the skirt portion 67 of the end cap 53 in the longitudinal direction X1, and is positioned in the rear end portion 34 of the outer tube 31. Therefore, the second protector 52 is placed on the right side of the first expansion chamber 45. The second protector 52 is narrower than the first protector 51. That is, a width W2 of the second protector 52 (dimension in a width direction V) is smaller than the width W1 of the constant width portion 61 of the first protector 51, for example, equal to or less than a half of the width W1.

[0051] The second protector 52 includes a flat portion 71 as a bar-like member extending in the longitudinal direction X1, and an upper rib 72 and a lower rib 73 both of which together form a pair of ribs extending in the longitudinal direction X1. A cross section of the flat portion 71 (a cross section normal to the longitudinal direction of the flat portion 71) has a generally rectangular shape elongating in the width direction Y1. When the muffler body 24 is viewed from a right side location, the flat portion 71 is arranged to face a center part of the muffler body 24 in the width direction Y1. A distal end portion 71 a of the flat portion 71 and the tapered portion 62 of the first protector 51 are adjacent to each other and are lined in the longitudinal direction X1. A pair of width direction side hems 71 b, 71 c of the flat portion 71 is formed to have a length corresponding to a configuration of a facing end of the tapered portion 62. That is, the width direction side hem 71 b positioned on the upper side is comparatively shorter, and the width direction side hem 71 c positioned on the lower side is comparatively longer.

[0052] A distal end portion hem of the flat portion 71 inclines relative to the longitudinal direction X1 in corresponding to the configuration of the facing end of the tapered portion 62 of the first protector 51. The distal end portion 71 a as one end of the flat portion 71 and the tapered portion 62 as one end of the first protector 51 are placed off from each other in the longitudinal direction X1 so that the distal end portion 71a and the tapered portion 62 overlap in the width direction Y1.

[0053] FIG. 10 is a cross sectional view taken along the line X-X of FIG. 7. With reference to FIGs. 7 and 10, the upper rib 72 and the lower rib 73 are provided to individually reinforce the flat portion 71. Each rib 72, 73 is formed along the respective corresponding width direction side hem 71b, 71c of the flat portion 71 and protrudes in a direction such that the respective rib recedes from the muffler body 24. Thus, the second protector 52 forms a U-shape in cross section.

[0054] Next, joining structures of the end cap 53 and the muffler body 24 will be described.

[0055] With reference to FIGs. 8 and 9, the end cap 53 and the muffler body 24 are joined to each other using a collar 74, a first screw 75, a first bracket 76, and a first weld nut 77. The collar 74 is inserted into an insertion aperture 70a defined to pierce a bottom wall 70 of the groove shaped portion 66 of the end cap 53.

[0056] The first bracket 76 is formed using a sheet metal member. An outer circumferential end portion of the first bracket 76 has a tongue-like piece 76a extending in a crank shape. A distal end portion of the tongue-like piece 76a is fixed to the rear end wall 33 of the muffler body 24. The first bracket 76 has an insertion aperture 76b. A shaft portion 75a of the first screw 75 extends through the insertion apertures 70a, 76b. The shaft portion 75a is screwed into the first weld nut 77 welded to the first bracket 76. Hence, the first bracket 76 and the bottom wall 70 of the end cap 53 are coupled together by the first screw 75 and the first weld nut 77.

[0057] A plurality of such joining structures (three in this embodiment) described above is provided at equal intervals along the circumferential direction of the groove shaped portion 66 of the end cap 53.

[0058] Next, a joining structure of the second protector 52 and the muffler body 24 will be described.

[0059] FIG. 11 is a cross sectional view taken along the line XI-XI of FIG. 7. With reference to FIGs. 7 and 11, a fixed section 78 is provided to the distal end portion 71 a of the flat portion 71. Also, a fixing section 79 is provided to the outer tube 31 of the muffler body 24. More in detail, the fixing section 79 is positioned at the most outside (right side) end in the middle portion of the third section 40 in the longitudinal direction.

[0060] The fixing section 79 and the fixed section 78 are joined to each other using a second bracket 80, a second screw 81, a bush 82, and a second weld nut 83. The second bracket 80 is formed using a sheet metal member. The second bracket 80 includes a pair of support portions 84, 85 lined in the longitudinal direction X1 and fixed to the fixing section 79, and a seat portion 86 both ends of which are supported by the support portions 84, 85. The seat portion 86 is positioned to be spaced apart from the muffler body 24 in relation to the fixing section 79. The bush 82 is annularly formed and is inserted into an insertion aperture 78a defined in the fixed section 78 to extend therethrough. The bush 82 includes an elastic member 88 having an annular groove 87 coupled with a circumferential part of the insertion aperture 78a, and a collar 89 fitted in an inner circumferential surface of the elastic member 88. A shaft portion 81a of the second screw 81 is inserted into the collar 89. The shaft portion 81 a is screwed into the second weld nut 83 welded to the seat portion 86. Hence, the bush 82 is interposed between a head portion 81 b of the second screw 81 and the second weld nut 90.

[0061] Next, a joining structure of the first protector 51 and the muffler body 24 will be described.

[0062] FIG. 12 is a cross sectional view of the major part taken along the line XII-XII of FIG. 7.

[0063] With reference to FIGs. 7 and 12, a fixed section 91 is provided at a rear end part 62c of the tapered portion 62. Also, a fixing section 92 is provided to the third section 40 of the outer tube 31. More in detail, the fixing section 92 is positioned on the right side surface 24c of the muffler body 24 in the middle portion of the third section 40 in the longitudinal direction.

[0064] The fixing section 92 and the fixed section 91 are joined to each other using a third bracket 93, a third screw 94, a bush 82, and a third weld nut 95. The third bracket 93 is formed using a sheet metal member. The third bracket 93 includes a support portion 96 fixed to the fixing section 92 and having a reversed U-shape in cross section, and a cantilever 98 cantilevered by the support portion 96. The cantilever 98 extends from the support portion 96 in a circumferential direction along the surface of the outer tube 31 of the muffler body 24. A distal end portion 98a of the cantilever 98 is used as a seat portion that carries the third weld nut 95.

[0065] The bush 82 is inserted into an insertion aperture 91a defined in the fixed section 91 to extend therethrough. An annular groove 87 of an elastic member 88 is coupled with a circumferential part of the insertion aperture 91a. A shaft portion 94a of the third screw 94 is inserted into a collar 89. The shaft portion 94a is screwed into the third weld nut 95 welded to the distal end portion 98a of the cantilever 98. Hence, the bush 82 is interposed by a head portion 94b of the third screw 94 and the third weld nut 95.

[0066] Also, a fixed section 101 is provided to the rear end portion 61 c of the constant width portion 61. In corresponding to this structure, a fixing section 102 is provided to the muffler body 24. More in detail, the fixing section 102 is positioned on the right side surface 24c of the muffler body 24 in the middle portion of the third section 40 of the outer tube 31 in the longitudinal direction.

[0067] The fixing section 101 and the fixed section 102 are joined to each other using a third bracket 93, a third screw 94, a bush 82, and a third weld nut 95. A joining structure of the fixing section 101 and the fixed section 102 is the same as the joining structure of the fixing section 92 and the fixed section 91 except for that the cantilever 98 of the third bracket 93 that joins the fixed section 101 and the fixed section 102 with each other extends in the longitudinal direction X1. Therefore, the corresponding structural elements in both of the joining structures are indicated by the same reference numerals and symbols.

[0068] FIG. 13 is a cross sectional view taken along the line XIII-XIII of FIG. 7. With reference to FIGs. 7 and 13, a top end portion 61 b of the constant width portion 61 of the first protector 51 is supported using a bracket 105, a support member 106 and a joining member 107. The bracket 105 has a reversed U-shape and is fixed to the third section 40 of the muffler body 24. More in detail, the bracket 105 is fixed to the middle portion in the longitudinal direction in an area close to a top end of the right side surface of the third section 40. A middle portion of the bracket 105 and the support member 106 are joined to each other using the joining member 107. The support member 106 receives a top end portion 61d of the constant width portion 61 of the first protector 51.

[0069] FIG. 14 is a cross sectional view of the major part taken along the line XIV-XIV of FIG. 2. With reference to FIGs. 2 and 14, a fixed section 113 is provided to a front end portion 61 a of the constant width portion 61. The fixed section 113 is positioned at the top end portion 61 d in the front end portion 61 a. A fixing section 114 corresponding to the fixed section 113 is provided to the muffler body 24. More specifically, the fixing section 114 is provided to the right side surface 24c of the muffler body 24, at the front end portion 40a of the third section 40. The fixing section 114 is positioned close to the top end of the front end portion 40a.

[0070] The fixing section 114 and the fixed section 113 are joined to each other using a third bracket 93, a third screw 94, a bush 82, and a third weld nut 95. Because a joining structure of the fixing section 114 and the fixed section 113 is the same as the joining structure of the fixing section 92 and the fixed section 91, corresponding structural elements are indicated by the same reference numerals and symbols.

[0071] Also, a fixed section 116 is provided to the front end portion 61 a of the constant width portion 61. The fixed section 116 is positioned at a bottom end portion 61e in the front end portion 61a. A fixing section 117 corresponding to the fixed section 116 is provided to the muffler body 24. More in detail, the fixing section 117 is provided to the right side surface 24c of the muffler body 24, at the front end portion 40a of the third section 40. The fixing section 117 is positioned close to the bottom end in the front end portion 40a.

[0072] The fixing section 117 and the fixed section 116 are joined to each other using a third bracket 93, a third screw 94, a bush 82, and a third weld nut 95. A joining structure of the fixing section 117 and the fixed section 116 is the same as the joining structure of the fixing section 92 and the fixed section 91 except for that the cantilever 98 of the third bracket 93 extends in the longitudinal direction X1. Therefore, the corresponding structural elements in both of the joining structures are indicated by the same reference numerals and symbols.

[0073] FIG. 15 is a cross sectional view of the major part taken along the line XV-XV of FIG. 2. With reference to FIGs. 2 and 15, a fixed section 118 is provided to a front end portion 58a of the front side section 58. A fixing section 119 corresponding to the fixed section 118 is provided to the muffler body 24. More in detail, the fixing section 119 is provided to the right side surface 24c of the muffler body 24, at the middle portion 39b of the second section 39.

[0074] The fixing section 119 and the fixed section 118 are joined to each other using a third bracket 93, a third screw 94, a bush 82, and a third weld nut 95. A joining structure of the fixing section 119 and the fixed section 118 is the same as the joining structure of the fixing section 92 and the fixed section 91 except for that the cantilever 98 of the third bracket 93 generally extends in the longitudinal direction X1. Therefore, the corresponding structural elements in both of the joining structures are indicated by the same reference numerals and symbols.

[0075] As thus described, in accordance with the embodiment, the first protector 51 and the second protector 52 are positioned to be spaced apart from each other in the longitudinal direction X1. Thereby, a large area of the right side surface 24c of the muffler body 24 can be protected, and hence the muffler body 24 can be sufficiently protected.

[0076] Also, the second protector 52 uncovers the top area 24d of the muffler body 24, and is narrower than the first protector 51 in the right side view. Thereby, heat can be sufficiently radiated to the top area and the right side of the muffler body 24, and hence the heat radiation performance of the muffler body 24 can be sufficiently kept. Consequently, the cooling performance of the muffler body 24 can be improved.

[0077] Because the second protector 52 extends in the longitudinal direction X1, an area in which the second protector 52 protects the muffler body 24 can be wider in the longitudinal direction X1. An uncovered area in the top area 24d and the right side surface 24c of the muffler body 24 can be wider, and hence the heat radiation from the muffler body 24 can be more surely made.

[0078] In addition, because the second protector 52 is formed to be a flat shape which is a simple configuration, the production thereof is easy.

[0079] Because the flat portion 71 is enforced by the pair of ribs 72, 73, the strength (specifically, the flexural rigidity) of the second protector 52 can be enhanced. Thereby, the muffler body 24 can be surely protected.

[0080] Further, the pair of ribs72, 73 is formed along both the width direction side hems 71 b, 71 c of the flat portion 71. Thereby, the flexural rigidity of the flat portion 71 can be more enhanced.

[0081] Each rib 72, 73 protrudes in the direction such that the respective rib recedes from the muffler body 24. Thus, an object which is going to touch the muffler body 24 can be received with the respective ribs 72, 73. Accordingly, the respective ribs 72, 73 can not only enforce the flat portion 71 but also can carry a function for protecting the muffler body 24.

[0082] Further, because the second protector 52 and the end cap 53 are unitarily formed, the number of parts can be reduced in comparison with a case in which the second protector 52 and the end cap 53 are separately formed.

[0083] On the other hand, although the number of parts can be reduced by forming the first protector structural member 54 and the second protector structural member 63 in a single molding piece, such a molding piece can be a large part and thus handling thereof can be difficult. This is because the first protector 51 that needs to cover the right side surface 24c of the muffler 24 is necessarily a large part. In contrast, the end cap 53 that is only required to cover the rear end surface 24a of the muffler body 24 is a part smaller than the first protector 54. Accordingly, the synthetic resin member 65 made in such a manner that the end cap structural member 64 and the second structural member 63 are unitarily formed can be formed small. Work required to produce, transport, store, and so forth for such a small synthetic resin member 65 can be light.

[0084] The tapered portion 62 of the first protector 51 and the distal end portion 71a of the flat portion 71 of the second protector 52 are arranged to overlap with each other in the width direction Y1. As a result, no area in which the muffler body 24 is uncovered exists all over the entire region in the width direction Y1, between the first protector 51 and the second protector 52. Thus, the range in which the muffler body 24 is protected by the first and second protectors 51, 52 can be widened.

[0085] The second protector 52 is positioned in the rear end portion 24b of the muffler body 24. Hence, the second protector 52 and the end cap 53 protect the rear end portion 24b of the muffler body 24 in collaboration with each other. The rear end portion 24b of the muffler body 24 can be more surely protected, accordingly.

[0086] The second protector 52 is positioned outside of the first expansion chamber 45. The second protector 52 is narrower than the first protector 51 and uncovers the top area of the muffler body 24. Therefore, the heat of the first expansion chamber 45 can be efficiently radiated from the surface of the muffler body 24. Thus, the first expansion chamber 45 can be sufficiently protected without preventing the heat of the first expansion chamber 45 being radiated from the muffler body 24. On the other hand, the rear end surface 24a is surely covered by the end cap 53. Also, the exterior corresponding to the first and second catalysts 26, 27 which have the highest temperature is surely covered by the first protector 51.

[0087] The distal end portion 71 a of the second protector 52 is supported at the most outside end of the right side surface 24c of the muffler body 24. Thereby, the support rigidity of the second protector 52 can be sufficiently kept. Also, because the second protector 52 is positioned at the most outside end, if there is an object approaching the muffler body 24, the protector 52 can surely receive the object before the muffler body 24. Hence, the muffler body 24 can be more surely protected.

[0088] The fixing sections 92, 102, 114, 117, 119 positioned on the right side surface 24c of the muffler body 24 and the fixed sections 91, 101, 113, 116, 118 corresponding thereto and provided to the first protector 51 are joined to each other by the third bracket 93. The third bracket 93 has the cantilever 98. The first protector 51 is supported by the distal end portion 98a of the cantilever 98. Thereby, the corresponding fixed sections 91, 101, 113, 116, 118 can be arranged at the positions spaced apart from the respective fixing sections 92, 102, 114, 117, 119. Therefore, a heat transmission route from the muffler body 24 to the first protector 51 can be longer. Also, the flexibility in the arrangement of the respective fixing sections 92, 102, 114, 117, 119 of the muffler body 24 can be enhanced, and the flexibility in the arrangement of the respective fixed sections 91, 101, 113, 116, 118 of the first protector 51 can be enhanced.

[0089] Further, the first and second protectors 51, 52 are individually made of a synthetic resin material. Hence, the first and second protectors 51, 52 can be produced by a method such as an injection molding which is suitable for mass production. Also, the first and second protectors 51, 52 made of the synthetic resin material do not easily have a high temperature even when they receive heat from the muffler body 24.

[0090] Because of the above, the motorcycle 1 and the muffler protector unit 9 that can sufficiently protect the muffler body 24 and also can improve the cooling performance of the muffler body 24 can be realized.

[0091] Additionally, although the construction in which one second protector 52 is provided is described in the above embodiment, a plurality of (for example, two) second protectors 52 can be provided as shown, for example, in FIG. 16. In this alternative, the respective second protectors 52 can be arranged, for example, to line in the width direction Y1.

[0092] By such multiple second protectors 52 being provided as described above, a wider area of the right side surface 24c of the muffler body 24 can be protected by the second protectors 52.

[0093] In the respective embodiments, one of the ribs 72, 73 of the second protector 52 or both thereof can be omitted.

[0094] The second protector 52 and the end cap 53 can be separately formed. The second protector 52 can be positioned on a right side of the second expansion chamber 46. Also, the second protector 52 can be placed at a central position of the muffler body 24 in the longitudinal direction X1. Further, the end cap 53 can cover the entire area of the rear end surface 24a of the muffler body 24.

[0095] The muffler body 24 and the muffler protector unit 9 can be symmetrically arranged on both right and left sides.

[0096] Other than those, various design modifications can be made within the scope recited in the claims.

[0097] As thus described above, this invention is useful for vehicles such as a motorcycle, and muffler protector units.

Description of Reference Numerals and Symbols

[0098] 1: motorcycle (vehicle), 2: vehicle body frame (vehicle body),7: engine, 9: muffler protector unit, 24: muffler body, 24a: rear end surface (of the muffler body), 24b: rear end portion (of the muffler body), 24c: right side surface (of the muffler body), 24d: top area (of the muffler body), 45: first expansion chamber, 46: second expansion chamber, 51: first protector, 52: second protector, 53: end cap, 58a: front end portion (a portion of the first protector), 61: constant width portion, 61a: front end portion (a portion of the first protector), 62: tapered portion (one end portion of the first protector), 62c: rear end portion (a portion of the first protector), 63: second protector structural member, 64: end cap structural member, 71: flat portion (bar-like member), 71a: distal end portion (one end portion of the second protector, a portion thereof), 71 b, 71 c: width direction side hem, 72: upper rib (one of a pair of ribs), 73: lower rib (the other one of the pair of ribs), 78: fixed section (of the second protector), 79: fixing section (of the second protector), 80: bracket (of the second protector), 91, 101, 113, 116, 118: fixed section (of the first protector), 92, 102, 114, 117, 119: fixing section (of the first protector), 93: third bracket, 96: support portion (of the third bracket 93), 98: cantilever, 98a: distal end portion (of the cantilever), X1: longitudinal direction, Y1: width direction.

Claims

1. A vehicle comprising: a tubular muffler body positioned on one side of a vehicle body;

an end cap covering at least a portion of a rear end surface of the muffler body;

a first protector covering at least a portion of a lateral side surface of the muffler body and positioned on an opposite side of the muffler body relative to the vehicle body; and

a second protector positioned in the rear of the first protector so as to be spaced apart therefrom in a longitudinal direction of the muffler body, covering the lateral side surface of the muffler body, uncovering a top area of the muffler body, and being narrower than the first protector in a width direction normal to the longitudinal direction of the muffler body in a lateral side view.

2. The vehicle according to Claim 1, wherein the second protector extends in the longitudinal direction of the muffler body.

3. The vehicle according to Claim 2, wherein the second protector includes a bar-like member.

4. The vehicle according to Claim 3, wherein the bar-like member includes a flat portion.

5. The vehicle according to Claim 4, wherein the bar-like member includes a rib formed on the flat portion in a longitudinal direction of the bar-like member.

6. The vehicle according to Claim 4, wherein the bar-like member includes a pair of ribs formed on the flat portion in the longitudinal direction of the bar-like member.

7. The vehicle according to Claim 6, wherein the pair of ribs are formed along both the width direction side hems of the flat portion.

8. The vehicle according to any one of Claims 5-7, wherein the rib protrudes in a direction in which the rib recedes from the muffler body.

9. The vehicle according to any one of Claims 1-8, comprising a second protector structural member for structuring the second protector, and an end cap structural member formed unitarily with the second protector structural member for structuring the end cap.

10. The vehicle according to any one of Claims 1-9, wherein one end portion of the first protector in the longitudinal direction of the muffler body and one end portion of the second protector in the longitudinal direction of the muffler body are placed off from each other to overlap in the width direction.

11. The vehicle according to any one of Claims 1-10, wherein the second protector is placed in a rear end portion of the muffler body in the longitudinal direction of the muffler body.

12. The vehicle according to any one of Claims 1-11, wherein the muffler body comprises a first expansion chamber defined within the muffler body, into which exhaust gases from an engine are introduced; and a second expansion chamber defined within the muffler body to communicate with the first expansion chamber, and
the second protector is positioned outside of the first expansion chamber.

13. The vehicle according to Claim 12 comprising the engine mounted to the vehicle body, wherein the engine, the second expansion chamber and the first expansion chamber are lined in this order front to rear along the vehicle body.

14. The vehicle according to any one of Claims 1-13 further comprising a bracket which joins a fixing section positioned at the most outside end of the lateral side surface of the muffler body and a fixed section positioned at a portion of the second protector to each other.

15. The vehicle according to any one of Claims 1-14 further comprising a bracket which joins a fixing section positioned at the lateral side surface of the muffler body and a fixed section positioned at a portion of the first protector to each other, wherein
the bracket comprises a supporting section fixed to the lateral side surface of the muffler body; and a cantilever cantilevered by the supporting section, extending from the supporting section along a surface of the muffler body, and having the fixed section fixed to a distal end portion thereof.

16. The vehicle according to any one of Claims 1-15, wherein the second protector is formed with a synthetic resin material.

17. The vehicle according to any one of Claims 1-16, wherein the second protector includes a plurality of second protectors.

18. A muffler protector unit comprising, an end cap covering at least a portion of a rear end surface of a muffler body;
a first protector covering at least a portion of a lateral side surface of the muffler body; and
a second protector positioned in the rear of the first protector so as to be spaced apart therefrom, and being narrower than the first protector in a width direction normal to the longitudinal direction of the muffler body in a lateral side view to cover the lateral side surface of the muffler body and to uncover a top area of the muffler body.

Drawing