JP2012229630A - Engine for saddle-type vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To constitute an exhaust muffler in any polygonal shape at low cost, in an engine for a saddle-type vehicle in which an exhaust system having the exhaust muffler at an end of the downstream is connected to a cylinder head of an engine body mounted on a vehicle body frame and a cross sectional shape of at least part of a casing of the exhaust muffler is formed in a polygonal shape.SOLUTION: The casing 49 includes: a cylindrical part 50 of which cross sectional shape is circular; and a polygonal cylindrical part 51 of which at least part of the cross sectional shape is polygonal and which is arranged at the rearmost of the casing 49.

Description

  In the present invention, an exhaust device having an exhaust muffler at a downstream end is connected to a cylinder head of an engine body mounted on a vehicle body frame, and at least a part of a cross-sectional shape of a casing of the exhaust muffler is formed in a polygon. The present invention relates to a saddle-ride type vehicle engine.

  Japanese Patent Application Laid-Open No. 2003-26069 discloses a motorcycle whose exhaust muffler casing has a polygonal cross-sectional shape and is covered with a part of the side cover of the vehicle body cover. Patent Document 2 discloses that a protector that covers a casing having a circular cross-sectional shape of a casing of an exhaust muffler included in is formed in a polygonal shape when viewed from the rear.

Japanese Patent Laid-Open No. 03-066461 JP 2009-16093 A

  However, in the one disclosed in Patent Document 1, the entire casing is formed so as to have a polygonal cross-sectional shape composed of a plurality of planes. Costs also increase. Moreover, in what is disclosed by the said patent document 2, since the whole exhaust muffler is shown in polygonal shape by covering the whole cylindrical casing with the protector which has a polygonal cross-sectional shape, exhaust muffler inevitably Appearance becomes large.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a saddle-ride type vehicle engine in which an exhaust muffler can be configured in an arbitrary polygonal shape at low cost.

  In order to achieve the above object, according to the present invention, an exhaust device having an exhaust muffler at a downstream end is connected to a cylinder head of an engine body mounted on a vehicle body frame, and a cross section of at least a part of a casing of the exhaust muffler. In a saddle-ride type vehicle engine having a polygonal shape, the casing is arranged in a circular cylindrical portion with a circular cross-sectional shape and at least a part of the cross-sectional shape as a polygonal shape at the rearmost portion of the casing. It is a 1st characteristic to provide the polygonal cylinder part made.

  According to the present invention, in addition to the configuration of the first feature, the polygonal cylinder part, which is separate from the circular cylinder part, has a separator at the front end that divides the inside of the casing into a plurality of bottomed cylinders. The rear end opening of the front cylindrical member formed in a shape and the front end opening of the rear cylindrical member formed in a bottomed cylindrical shape having a rear end wall with the outer surface as a design surface at the rear end The second feature is that the front end portion of the front cylindrical member is connected to the rear end of the circular cylindrical portion.

  In the present invention, in addition to the configuration of the first or second feature, the polygonal cylindrical portion has a circular cross-sectional shape at the front end thereof, and gradually changes the cross-sectional shape to a polygonal shape toward the rear end. The third feature is to form them.

  According to the present invention, in addition to any of the configurations of the first to third features, a protector that covers at least a side surface of the casing and covers a part of the upper surface includes a coupling portion of the circular cylindrical portion and the polygonal cylindrical portion. It is the fourth feature that it is arranged so as to cover.

  According to a fifth feature of the present invention, in addition to the fourth feature, the protector comprises a front protector that covers the front portion of the casing and a rear protector that covers the rear portion of the casing. To do.

  In addition to any of the configurations of the first to fifth features, the present invention provides that the engine body disposed between the front wheels and the rear wheels has a crankcase and a front side tilted upward from the crankcase. An exhaust pipe comprising an upwardly extending cylinder block and the cylinder head coupled to an upper portion of the cylinder block, and constituting an part of the exhaust device and having an upstream end connected to a front side wall of the cylinder head The exhaust is disposed in the casing of the exhaust muffler, which is disposed so as to extend downward from the front of the engine main body and extend rearward, and is disposed at the rear of the crankcase and on the side of the rear wheel and inclined rearwardly. A sixth feature is that the tubes are connected.

  The front exhaust pipe 45 of the embodiment corresponds to the exhaust pipe of the present invention, and the rear separator 63 of the embodiment corresponds to the separator of the present invention.

  According to the first to sixth features of the present invention, the casing of the exhaust muffler includes a circular cylindrical portion having a circular cross-sectional shape and a polygonal cylindrical portion having at least a part of the cross-sectional shape polygonal. Since the entire casing has a polygonal cross-sectional shape composed of a plurality of planes, it is possible to solve the problem of noise and high production cost caused by an exhaust muffler with a combination of a circular cylindrical portion and a polygonal cylindrical portion, Moreover, the polygonal cylindrical portion can be formed in an arbitrary cross-sectional shape, and can contribute to the improvement of the appearance.

  In particular, according to the second feature of the present invention, the polygonal cylindrical part has a rear end opening part of a front cylindrical member having a separator at the front end and formed into a bottomed cylindrical shape, and the outer surface is a design surface. The front and rear cylinder members are formed by drawing because the rear end wall of the rear cylinder member formed in a bottomed cylindrical shape with the rear end wall at the rear end is coupled to each other. As described above, the manufacturing cost can be reduced by making it possible to manufacture the circular cylindrical portion in the same manner as the conventional cylindrical exhaust muffler while making the manufacturing not difficult.

  In particular, according to the third feature of the present invention, since the cross-sectional shape of the front end of the polygonal cylindrical portion is circular, it is possible to facilitate the coupling of the polygonal cylindrical portion to the circular cylindrical portion by welding.

  In particular, according to the fourth feature of the present invention, since the coupling part of the circular cylinder part and the polygonal cylinder part is covered with the protector, the coupling part of the circular cylinder part and the polygonal cylinder part is not visible from the outside. Moreover, since the polygonal cylinder part of the rearmost part of a casing is visually recognized from the exterior, the whole exhaust muffler can be shown to have a polygonal cross-sectional shape.

  More particularly, according to the fifth feature of the present invention, since the protector is constituted by the front protector that covers the front part of the casing and the rear protector that covers the rear part of the casing, the material for forming the front part and the rear protector It is possible to easily change the colors of the front and rear protectors.

1 is a right side view of a motorcycle. It is a top view of an exhaust apparatus. It is a partially notched top view of the exhaust muffler in the state where the protector is removed. FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. FIG. 5 is a view taken in the direction of arrow 5 in FIG. 4.

  The embodiment of the present invention will be described with reference to FIGS. 1 to 5 attached herewith. First, in FIG. 1, a body frame F of a motorcycle, which is a saddle-ride type vehicle, pivotally supports a front wheel WF at a lower end portion. A head pipe 12 that supports the front fork 11 so as to be steerable, a main frame 13 that extends rearward and downward from an upper portion of the head pipe 12, and a center that extends downward from the rear portion of the main frame 13 and is continuous with the main frame 13. A frame 14, a down frame 15 extending rearward and downward from the lower portion of the head pipe 12 at a steeper angle than the main frame 13, a pair of left and right pivot plates 16 provided at the lower portion of the center frame 14, and the main frame 13 and a pair of left and right seat rails 17 extending rearward from the rear portion, and the pivot plate 1 ... comprises extending the seat rails 17 of the left-right pair of ... is connected to an intermediate portion of the subframe 18 ... in a rearward and upward from.

  On the pivot plate 16..., A front end portion of a swing arm 19 that pivotally supports the rear wheel WR at the rear portion is supported through a support shaft 20 so as to be swingable. The main frame 13 and the center frame 14 are connected to each other. A rear cushion unit 23 is provided between the upper support plate 21 provided in the installation portion and the lower support plate 22 provided on the upper portion of the swing arm 19.

  A fuel tank 25 straddling the main frame 13 is supported on the main frame 13, and a tandem riding seat 26 disposed behind the fuel tank 25 is supported by the seat rails 17.

  Between the front wheel WF and the rear wheel WR, an engine body 27 of an engine E that is an air-cooled four-cycle single cylinder is disposed. The engine body 27 includes a crankcase 28 and a crankcase 28. A cylinder block 29 that is inclined slightly upward from the front and extends forward and upward; a cylinder head 30 coupled to the upper portion of the cylinder block 29; and a head cover 31 coupled to the cylinder head 30; A front portion of the crankcase 28 is fastened to a hanger 32 provided at a lower end portion of the down frame 15, and a rear portion of the crankcase 28 is fastened to the pivot plate 16.

  A transmission (not shown) is built in the crankcase 28, the output shaft 34 of the transmission projects from the left side surface of the crankcase 28, and a drive sprocket 35 is provided at the projecting end of the output shaft 34. Fixed. On the other hand, a driven sprocket 37 is fixed to the axle 36 of the rear wheel WR, and an endless chain 38 is wound around the drive sprocket 35 and the driven sprocket 37.

  The intake device 39 provided in the engine E includes an air cleaner 40 disposed below the riding seat 26, a connecting tube 41 having an upstream end connected to the air cleaner 40, and an upstream end at the downstream end of the connecting tube 41. Is connected to the throttle body 42 and an intake pipe 43 connecting the downstream end of the throttle body 42 and the rear side wall of the cylinder head 30. A fuel injection valve (not shown) is provided in the throttle body 42. It is attached.

  Referring also to FIG. 2, the exhaust device 44 provided in the engine E has an upstream end connected to the front side wall of the cylinder head 30 and extends backward from the front of the engine body 27 downward. A front exhaust pipe 45 that is bent in such a manner, an exhaust purification device 46 connected to a downstream end of the front exhaust pipe 45 below the engine body 27, and an upstream end to the exhaust purification device 46 Is connected to the rear exhaust pipe 47, and an exhaust muffler 48 connected to the rear exhaust pipe 47 and disposed on the right side of the rear wheel WR.

  3 and 4 together, the exhaust muffler 48 provided at the downstream end of the exhaust device 44 is disposed behind the crankcase 28 and on the side of the rear wheel WR and tilts rearwardly upward. The casing 49 of the exhaust muffler 48 is formed such that at least a part of the cross-sectional shape thereof is a polygon. Thus, the casing 49 includes a circular cylindrical portion 50 having a circular cross-sectional shape, and a polygonal cylindrical portion 51 disposed at the rearmost portion of the casing 49 with at least a partial cross-sectional shape being a polygonal shape. .

  The circular cylindrical portion 50 includes a first tapered cylindrical member 52 formed so as to increase in diameter toward the rear so that an intermediate portion of the rear exhaust pipe 47 passes through the front small diameter end portion, A second tapered cylindrical member 53 having a diameter increasing toward the rear so that the front small-diameter end is coupled to the rear large-diameter end of the tapered cylindrical member 52 by welding, and the rear small-diameter of the second tapered cylindrical member 53. A first cylindrical member 54 whose front end is coupled to the end by welding, and a second cylindrical member 55 whose front end is coaxially coupled to the rear end of the first cylindrical member 54 by welding.

  A disc-shaped front separator 56 is fixed to the inner peripheral surface of the rear end portion of the first cylindrical member 54 by welding, and the first expansion chamber 57 is placed in the circular cylindrical portion 50 in front of the front separator 56. Is formed. In addition, the downstream end of the rear exhaust pipe 47 is inserted into the first expansion chamber 57, and the downstream end of the rear exhaust pipe 47 is inserted into and supported by the inner periphery of the rear end of the second tapered tubular member 53. The holder 58 is fixed by welding, and the holder 58 is formed to have a plurality of, for example, three flow holes 59, 59... So as not to divide the first expansion chamber 57 forward and backward. .

  Referring also to FIG. 5, the polygonal cylinder portion 51, which is a separate body from the circular cylinder portion 50, has a rear separator 63 that divides the inside of the casing 49 into a plurality of pieces, and has a bottom. The rear cylindrical member 62 is formed in a bottomed cylindrical shape integrally having a rear end opening portion of the front cylindrical member 61 formed in a cylindrical shape and a rear end wall 64 having an outer surface as a design surface at the rear end. The front end opening is connected to each other, and the cross-sectional area of the polygonal cylinder 51 is set larger than the cross-sectional area of the circular cylinder 50. Moreover, the front cylinder member 61 and the rear cylinder member 62 are both drawn.

  The polygonal cylinder part 51 is formed so that the cross-sectional shape of the front end is circular and the cross-sectional shape is gradually changed to a polygonal shape toward the rear end. The cross-sectional shape of the front end, that is, the cross-sectional shape of the front end of the front cylindrical member 61 is circular, and the front end of the front cylindrical member 61 is joined to the rear end of the circular cylindrical portion 50 by welding.

  A second expansion chamber 65 is formed between the rear separator 63 and the rear end wall 64 in the polygonal cylindrical portion 51, and a second expansion chamber 65 is formed between the front separator 56 and the rear separator 63 in the rear portion of the circular cylindrical portion 50. A three expansion chamber 66 is formed.

  The first expansion chamber 57 and the second expansion chamber 65 are communicated with each other via a first communication pipe 67 that passes through the front separator 56 and the rear separator 63, and between the second expansion chamber 65 and the third expansion chamber 66. Are communicated via a second communication pipe 68 that passes through the rear separator 63. Further, the front end portion of the tail pipe 69 is communicated with the third expansion chamber 66, and this tail pipe 69 penetrates the rear separator 63 and the concave portion 64 a formed in the central portion of the rear end wall 64. It protrudes backward.

  A mounting plate 75 is fixed to an upper portion of the casing 49 near the rear end of the circular cylinder portion 50, and the mounting plate 75 is fastened to a lower portion of a stay 74 that is suspended from the rear portion of the vehicle body frame F.

  By the way, at least a part of the side surface and the upper surface of the casing 49 is covered with a protector 70. The protector 70 includes a front protector 71 that covers the front portion of the casing 49 and a rear protector that covers the rear portion of the casing 49. 72, and the connecting portion of the circular cylindrical portion 50 and the polygonal cylindrical portion 51 is covered with a rear protector 72.

  Next, the operation of this embodiment will be described. A casing 49 of an exhaust muffler 48 provided at the downstream end of the exhaust device 44 includes a circular cylindrical portion 50 having a circular cross-sectional shape, and at least a partial cross-sectional shape. And a polygonal cylindrical part 51 arranged at the rearmost part of the casing 49 as a polygonal shape, so that the noise generated by the exhaust muffler having a polygonal cross-sectional shape consisting of a plurality of planes as a whole and a high production cost This problem can be solved by a combination of the circular cylindrical portion 50 and the polygonal cylindrical portion 51, and the polygonal cylindrical portion 51 can be formed in an arbitrary cross-sectional shape, thereby improving the appearance. Can contribute.

  Further, a front cylindrical member 61 is formed in a bottomed cylindrical shape, in which a polygonal cylindrical portion 51 that is a separate body from the circular cylindrical portion 50 has a rear separator 63 that divides the inside of the casing 49 into a plurality of pieces at the front end. The rear end opening portion and the front end opening portion of the rear cylindrical member 62 formed integrally with the rear end wall 64 having a rear end wall 64 having an outer surface as a design surface at the rear end are coupled to each other. Since the front end portion of the front cylinder member 61 is coupled to the rear end of the circular cylinder portion 50, the front and rear cylinder members 61 and 62 are formed by drawing so that the manufacture is not difficult. The manufacturing cost can be reduced by making it possible to manufacture the circular cylindrical portion 51 in the same manner as a conventional cylindrical exhaust muffler.

  Further, the polygonal cylinder portion 51 is formed so as to have a circular cross-sectional shape at the front end thereof and to gradually change the cross-sectional shape to a polygonal shape toward the rear end, so that the circular cylinder of the polygonal cylinder portion 51 is formed. The connection to the part 50 by welding can be facilitated.

  Further, since the protector 70 that covers at least the side surface of the casing 49 and covers a part of the upper surface is disposed so as to cover the coupling portion of the circular cylindrical portion 50 and the polygonal cylindrical portion 51, the circular cylindrical portion 50 and the polygonal shape are provided. The appearance can be enhanced by preventing the coupling portion of the cylindrical portion 51 from being seen from the outside, and since the polygonal cylindrical portion 51 at the rearmost portion of the casing 49 is visually recognized from the outside, the entire exhaust muffler 48 is polygonal. It can appear to have a cross-sectional shape.

  Moreover, since the protector 70 is comprised by the front part protector 71 which covers the front part of the casing 49, and the rear part protector 72 which covers the rear part of the said casing 49, the material which forms the front part and the rear part protectors 71 and 72 is used, for example. It is possible to easily change one so that the other is made of metal while the other is made of resin, or to change the colors of the front and rear protectors 71 and 72.

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

  For example, in the above-described embodiment, the protector 70 is divided into the front protector 71 and the rear protector 72. However, the protector 70 that is not divided may cover the joint portion of the circular cylindrical portion 50 and the polygonal cylindrical portion 51. .

27 ... Engine body 28 ... Crank case 29 ... Cylinder block 30 ... Cylinder head 44 ... Exhaust device 45 ... Front exhaust pipe 48 which is an exhaust pipe ... Exhaust muffler 49 ··· Casing 50 ··· Circular cylinder portion 51 ··· Polygonal cylinder portion 61 ··· Front cylinder member 62 ··· Rear cylinder member 63 ··· Rear separator 64 that is a separator · · · Rear end wall 70 ... Protector 71 ... Front protector 72 ... Rear protector E ... Engine F ... Car body frame WF ... Front wheel WR ... Rear wheel

Claims (6)

  An exhaust device (44) having an exhaust muffler (48) at the downstream end is connected to a cylinder head (30) of an engine main body (27) mounted on the vehicle body frame (F), and a casing of the exhaust muffler (48) ( 49) In the saddle-ride type vehicle engine in which at least a part of the cross-sectional shape is formed in a polygon, the casing (49) includes a circular cylindrical part (50) having a circular cross-sectional shape and at least a part of the casing (49). A saddle-ride type vehicle engine comprising: a polygonal cylindrical portion (51) disposed at the rearmost portion of the casing (49) with a cross-sectional shape of   The polygonal cylinder part (51), which is a separate body from the circular cylinder part (50), has a separator (63) that divides the inside of the casing (49) into a plurality of pieces at the front end, and has a bottomed cylindrical shape. A rear cylindrical member formed integrally with a rear end opening of a front cylindrical member (61) formed on the rear end wall (64) having a design surface as an outer surface at the rear end. The front end opening of (62) is connected to each other, and the front end of the front tube member (61) is connected to the rear end of the circular tube (50). Engine for saddle-ride type vehicles.   The said polygonal cylinder part (51) is formed so that the cross-sectional shape of the front end may be circular and the cross-sectional shape may be gradually changed to a polygonal shape toward the rear end. Or a saddle-ride type vehicle engine according to 2;   A protector (70) that covers at least the side surface of the casing (49) and a part of the upper surface thereof is disposed so as to cover the coupling portion of the circular tube portion (50) and the polygonal tube portion (51). The saddle-ride type vehicle engine according to any one of claims 1 to 3.   The said protector (70) is comprised by the front part protector (71) which covers the front part of the said casing (49), and the rear part protector (72) which covers the rear part of the said casing (49), Item 5. The saddle-ride type vehicle engine according to Item 4.   The engine body (27) disposed between the front wheel (WF) and the rear wheel (WR) has a crankcase (28) and a cylinder block (inclined forwardly from the crankcase (28) and extending forward and upward) 29) and the cylinder head (30) coupled to the upper portion of the cylinder block (29), and constitutes a part of the exhaust device (44) to form a front side wall of the cylinder head (30). An exhaust pipe (45) to which the upstream end is connected is disposed so as to extend downward from the front of the engine body (27) and extend rearward, and behind the crankcase (28) and the rear wheel (WR). 6. The exhaust pipe (45) is connected to the casing (49) of the exhaust muffler (48) disposed on the side of the exhaust pipe and inclined rearwardly. of Ride type vehicle engine.

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