JP2017030420A - Structure for coupling exhaust pipe for motorcycle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce load on an exhaust pipe due to vibration and save a space for a structure for coupling the exhaust pipe.SOLUTION: The structure for coupling the exhaust pipes 5 to each other for a motorcycle 1 includes a coupling member 6 for coupling the adjacent multiple exhaust pipes 5 to each other and having an annular part 61 un-fixedly attached to respective outer peripheral surfaces of the multiple exhaust pipes 5 and a coupling part 62 for coupling annular parts 61 attached to respective outer peripheries of the adjacent multiple exhaust pipes 5 to each other.SELECTED DRAWING: Figure 5

Description

  The present invention relates to an exhaust pipe connection structure of a motorcycle. In particular, the present invention relates to a connection structure that connects a plurality of exhaust pipes drawn from each of a plurality of combustion chambers of a multi-cylinder engine.

  2. Description of the Related Art Some motorcycles having a multi-cylinder engine have a configuration in which a plurality of exhaust pipes drawn from a plurality of combustion chambers are gathered upstream of a silencer (muffler). For example, in a motorcycle having a four-cylinder engine, a configuration may be used in which four exhaust pipes are assembled into two, and further, two exhaust pipes are gathered into one downstream. . With such a configuration, stress tends to concentrate on the collection portion of the exhaust pipe due to vibration or the like, and therefore a configuration in which a reinforcing member is welded to the exhaust pipe is used. However, in the configuration in which the reinforcing member or the like is welded to the exhaust pipe, the stress tends to concentrate on the welded portion, and there is a problem that the size is increased and the weight is increased because strong reinforcement is required.

  In Patent Document 1 and Patent Document 2, as a configuration for preventing deformation of the exhaust pipe due to vibration, a belt-shaped reinforcing member (connecting member) is wound around two exhaust pipes, and the reinforcing member (connecting member) is The structure which couple | bonds the extension parts with the volt | bolt in the space between two exhaust pipes is disclosed.

JP 2002-155743 A Japanese Patent No. 4693721

  However, in the configurations described in Patent Document 1 and Patent Document 2, a space for coupling the extending portions of the reinforcing members must be provided between the two exhaust pipes. For this reason, in the configuration in which the two exhaust pipes are arranged in the vehicle width direction, the dimension in the vehicle width direction of the space for installing the exhaust pipe is increased, and the bank angle of the motorcycle is reduced. Moreover, since the installation space of the exhaust pipe is limited, the pipe length of the exhaust pipe cannot be increased.

  In view of the above circumstances, the problem to be solved by the present invention is to provide an exhaust pipe connection structure that can reduce the load on the exhaust pipe due to vibration and can save space.

  In order to solve the above-mentioned problem, the present invention provides a connection structure for a motorcycle exhaust pipe having a plurality of exhaust pipes, and includes a connection member that connects the plurality of adjacent exhaust pipes, and the connection member includes: An annular portion that is mounted without being fixed to the outer peripheral surface of each of the plurality of exhaust pipes, and two connecting portions that connect the annular portions that are mounted on the outer periphery of each of the adjacent exhaust pipes; Each of the two connecting portions is joined to the two annular portions on each side of a straight line passing through the center of the two annular portions.

Each of the two connecting portions may have a configuration in which both end portions are joined to the two annular portions and the intermediate portion is curved in a direction approaching each other.
Each end of each of the two connecting portions includes a contact point of a common outer tangent line of the plurality of exhaust pipes connected by the connecting member when viewed in the axial direction of the plurality of exhaust pipes connected by the connecting member. The structure which is contacting the outer peripheral surface of each of said some exhaust pipe in the range is applicable.

  At both ends of the connecting member, a substantially “V” -shaped concave or convex portion is provided, and the connecting member has two oblique sides of the “V” shape welded to the outer peripheral surface of the annular portion, The positions of the end portions of the welding range of the two oblique sides may be different from each other when viewed in the axial direction of the annular portion.

  A configuration in which an opening penetrating in the radial direction is provided in a portion where the connecting portion of the annular portion does not overlap is applicable.

  The connection member can be configured to be provided in the middle between the upstream end of the plurality of exhaust pipes and the gathering portion where the plurality of exhaust pipes gather.

  The connection member may be configured to be provided at a position where the axes of the plurality of exhaust pipes are not parallel.

  According to the present invention, by connecting the exhaust pipe with the connecting member, deformation and breakage of the exhaust pipe due to vibration can be prevented or suppressed. Further, since the exhaust pipes to be connected can be brought close to each other, space can be saved.

FIG. 1 is a right side view schematically showing a configuration example of a motorcycle. FIG. 2 is a bottom view schematically showing a configuration example of the exhaust pipe. FIG. 3 is a top view schematically showing a configuration example of the exhaust pipe. FIG. 4 is a cross-sectional view taken along the line IV-IV in FIGS. 2 and 3. FIG. 5 is a perspective view schematically showing a configuration example of the connecting member. FIG. 6 is a perspective view schematically showing a configuration example of the connecting member. FIG. 7 is a perspective view schematically showing an exhaust pipe connection structure using a connection member. FIG. 8 is a perspective view schematically showing an exhaust pipe connection structure using a connection member.

  Embodiments of the present invention will be described below in detail with reference to the drawings. In each figure, the front side of the motorcycle is indicated by an arrow “Fr”, the rear side is indicated by an arrow “Rr”, the right side is indicated by an arrow “R”, the left side is indicated by an arrow “L”, Is indicated by an arrow “Up”, and the lower side is indicated by an arrow “Dn”.

(Overall structure of motorcycle)
First, an example of the entire configuration of a motorcycle to which the exhaust pipe connection structure according to the present embodiment is applied will be described with reference to FIG. FIG. 1 is a right side view schematically showing a configuration example of the motorcycle 1. Here, an example of an on-road type motorcycle having a so-called twin spar frame is shown as an example of the motorcycle 1 to which the exhaust pipe connection structure according to the present embodiment is applied.

  A body frame 11 of the motorcycle 1 includes a steering head pipe 111 and a pair of left and right main frames 112. The steering head pipe 111 has a tubular configuration that tilts backward. The pair of left and right main frames 112 are joined integrally to the steering head pipe 111 at the front end, and extend rearward and obliquely downward while increasing the spacing in the vehicle width direction from the steering head pipe 111. A pair of left and right seat rails 12 are attached to the rear portion of the main frame 112. The pair of left and right seat rails 12 are members that support the seat 221 on which the occupant is seated, and extend from the rear of the main frame 112 toward the upper rear side at a predetermined interval in the vehicle width direction. Each part of the body frame 11 is formed of steel, aluminum alloy, or the like, and is integrally joined by welding or the like.

  On the front side of the body frame 11, a steering shaft (not visible in FIG. 1), a pair of left and right front forks 201, and a front wheel 202 are provided. The steering shaft is inserted into the steering head pipe 111 and is rotatably supported by the steering head pipe 111. The pair of left and right front forks 201 are connected to the steering shaft via a bracket or the like, and rotate integrally with the steering shaft. The front wheel 202 is rotatably supported by the lower ends of the pair of left and right front forks 201. A brake disc 203 that rotates integrally is attached to the front wheel 202. A brake caliper 204 and a front fender 206 that covers the upper side of the front wheel 202 are attached to the pair of left and right front forks 201. Further, left and right handle bars 205 (handle grips) are attached to upper ends of the pair of left and right front forks 201, respectively.

  A front end portion of the swing arm 211 is coupled to the rear portion of the vehicle body frame 11 so as to be swingable in the vertical direction (pitching direction). A rear wheel 212 is rotatably supported at the rear end of the swing arm 211. A driven sprocket 213 that rotates integrally with the rear wheel 212 is attached to the left side of the rear wheel 212. A drive chain 214 is wound around the driven sprocket 213 and a drive sprocket of the engine unit 4 (described later). The rotational power output from the engine unit 4 is transmitted to the rear wheel 212 via the drive chain 214. Further, between the body frame 11 and the swing arm 211, a shock absorber (not shown) that absorbs or reduces vibration and impact transmitted from the rear wheel 212 to the body frame 11 is provided. In addition, a rear fender 215 is provided above the rear wheel 212.

  In addition, the motorcycle 1 is provided with the seat 221 on which the passenger sits on the upper side of the seat rail 12 as described above. A fuel tank 222 is provided on the front side of the seat 221 and above the main frame 112. In addition, the motorcycle 1 includes a front cowl 231, a side cowl 232, and a seat cowl 233 as exterior members. The front cowl 231 covers the front part of the motorcycle 1, and the side cowl 232 covers the side part of the motorcycle 1. The seat cowl 233 covers the periphery of the seat 221. These exterior members are shell-shaped members made of, for example, a synthetic resin material. These exterior members constitute a design of the appearance of the motorcycle 1.

  An engine unit 4 that is an internal combustion engine is mounted on the body frame 11. The engine unit 4 is suspended from the vehicle body frame 11 via a plurality of engine mounts. The engine unit 4 also has a function as a strength member of the motorcycle 1.

  In the present embodiment, a multi-cylinder engine is applied to the engine unit 4. Here, a front exhaust type parallel four-cylinder engine is shown as an example of a multi-cylinder engine. The engine unit 4 includes a crankcase assembly 41, a cylinder block 43, a cylinder head 44, and a cylinder head cover 45. A crank chamber is provided at the front of the inside of the crankcase assembly 41, and a mission chamber is provided at the rear of the inside. A crankshaft is rotatably accommodated in the crank chamber. A transmission is provided inside the mission chamber. An end portion of the rotation output shaft of the transmission protrudes outside the crankcase assembly 41, and a drive sprocket is provided at the end portion of the rotation output shaft so as to rotate integrally. A drive chain 214 is wound around the drive sprocket and the driven sprocket 213 of the rear wheel 212. A clutch is provided on one side of the crankcase assembly 41 (for example, on the right side in the vehicle width direction), and a generator is provided above the crankcase assembly 41.

  The cylinder block 43 is provided on the upper side of the crankcase assembly 41. A plurality of cylinders are provided inside the cylinder block 43, and a piston is accommodated in each cylinder so as to be capable of reciprocating. In the present embodiment, four cylinders are arranged inside the cylinder block 43 in the vehicle width direction. The cylinder head 44 is provided on the upper side of the cylinder block 43. The cylinder head 44 includes, for each of a plurality of cylinders, an intake port serving as an air-fuel mixture passage, an exhaust port 441 serving as an exhaust passage, valves that open and close these passages, and a drive mechanism that drives these valves. Is provided. In the present embodiment, the intake port of each cylinder is provided on the rear surface side of the cylinder head 44 so as to be arranged in series in the vehicle width direction. Further, the exhaust port 441 of each cylinder is provided on the front side of the cylinder head 44 so as to be arranged in series in the vehicle width direction. The cylinder head cover 45 is provided on the upper side of the cylinder head 44 and covers the valve and the valve driving mechanism.

  On the upper rear side of the cylinder head 44, an unillustrated air cleaner that takes in and purifies the combustion air of the engine unit 4 is provided. For example, the air cleaner is provided between the pair of left and right main frames 112. On the rear side of the cylinder head 44, a throttle valve (not shown) for adjusting the amount of combustion air supplied to each cylinder is connected to each intake port of the plurality of cylinders. These throttle valves and an air cleaner are connected. For this reason, the combustion air taken in and purified by the air cleaner is adjusted in flow rate in the throttle valve and supplied to each cylinder from the intake port of each cylinder.

  An exhaust pipe 5 that is a path for guiding exhaust gas from each cylinder to a silencer 223 (muffler) is connected to an exhaust port 441 of each cylinder provided on the front side of the cylinder head 44. Each of the plurality (four in this embodiment) of exhaust pipes 5 passes through the front side and the lower side of the engine unit 4 and is drawn out to one side in the vehicle width direction (right side in the present embodiment). The plurality of exhaust pipes 5 are finally assembled into one, and a silencer 223 is connected to the rear end portion of the assembled exhaust pipes 5. Therefore, the exhaust gas generated in each cylinder is discharged to the outside through the exhaust port 441, the exhaust pipe 5 and the silencer 223 of each cylinder.

(Exhaust pipe configuration)
Next, a configuration example of the exhaust pipe 5 will be described with reference to FIGS. FIG. 2 is a bottom view schematically showing a configuration example of the exhaust pipe 5, and shows the engine unit 4 and the exhaust pipe 5 extracted from the motorcycle 1. FIG. 3 is a top view schematically showing a configuration example of the exhaust pipe 5. 4 is a cross-sectional view taken along the line IV-IV in FIGS. 2 and 3, and is a diagram schematically showing the arrangement structure of the exhaust pipe 5 on the lower side of the engine unit 4.

  As shown in these drawings, the motorcycle 1 according to the present embodiment has a plurality of exhaust pipes 5. Here, a configuration in which the motorcycle 1 has four exhaust pipes 5 is shown. In particular, as shown in FIG. 2, the upstream ends of the four exhaust pipes 5 are respectively connected to four exhaust ports 441 provided on the front side of the cylinder head 44 of the engine unit 4. Each of the four exhaust pipes 5 extends forward from the front side of the cylinder head 44, curves downward immediately before the cylinder head 44 and the cylinder block 43, and moves downward on the front side of the engine unit 4. Stretch toward. Each of the four exhaust pipes 5 curves rearward on the front lower side of the engine unit 4 and extends downward on the lower side of the engine unit 4.

  As shown in FIG. 4, an oil pan 46 is provided at the lowermost part of the engine unit 4 at a position deviated to one side from the center in the vehicle width direction. Each of the four exhaust pipes 5 is provided at a position deviated from the center in the vehicle width direction to one side opposite to the oil pan 46 in order to avoid interference with the oil pan 46. At the lower side of the engine unit 4, two exhaust pipes 5 drawn from the two exhaust ports 441 closer to the center of the engine unit 4 in the vehicle width direction are arranged side by side in the vehicle width direction. Further, below these, two exhaust pipes 5 drawn out from the two exhaust ports 441 at both ends are arranged side by side in the vehicle width direction.

  The two exhaust pipes 5 drawn out from the two exhaust ports 441 at both ends in the vehicle width direction are assembled into one exhaust pipe 5 at a position on the lower rear side of the engine unit 4. Similarly, the two exhaust pipes 5 drawn out from the two exhaust ports 441 near the center in the vehicle width direction are gathered into one exhaust pipe 5 at a position on the lower rear side of the engine unit 4. The For convenience of explanation, a portion where the plurality of exhaust pipes 5 are gathered is referred to as a “aggregating portion 51”. Then, the two exhaust pipes 5 assembled in the collecting unit 51 are collected into one on the further downstream side. The exhaust pipes 5 assembled into one are pulled out to the right in the vehicle width direction, and a silencer 223 is connected to the downstream end thereof (see FIG. 1).

  As described above, in the present embodiment, the plurality of exhaust pipes 5 connected to each of the exhaust ports 441 of each cylinder are assembled on the downstream side of each of the exhaust ports 441 and connected to the silencer 223. With such a configuration, the negative pressure inside the exhaust pipe 5 is amplified to increase the efficiency of inertial suction. In the configuration in which the plurality of exhaust pipes 5 are assembled in the collecting part 51, if the exhaust pipe 5 vibrates or deforms, stress concentrates on the collecting part 51, and the exhaust pipe 5 may be damaged in the collecting part 51. is there. Therefore, in the present embodiment, the plurality of exhaust pipes 5 to be assembled are connected by the connecting member 6 in the middle of the exhaust port 441 and the collecting portion 51. Thereby, vibration and deformation of the exhaust pipe 5 are suppressed or prevented, and damage to the exhaust pipe 5 in the collecting portion 51 is prevented or suppressed.

(Structure of connecting member)
Here, the structural example of the connection member 6 which connects the exhaust pipes 5 is demonstrated with reference to FIG. 5 and FIG. 5 and 6 are perspective views schematically showing a configuration example of the connecting member 6. 5 shows a configuration example of a connecting member 6 that connects two exhaust pipes 5 parallel to each other, and FIG. 6 shows a configuration example of a connecting member 6 that connects two exhaust pipes 5 that are not parallel to each other. Indicates. The connecting member 6 includes two annular portions 61 attached to the outer circumferences of the two exhaust pipes 5 and two connecting portions 62 that connect the two annular portions 61 to each other. The two annular portions 61 and the two connecting portions 62 are each formed of a metal material such as steel and are joined together by welding.

  5 and 6, the straight line A is the axis of the annular part 61 (the axis of the exhaust pipe 5 inserted through the annular part 61). The straight line L is a straight line that passes through the centers of the two annular portions 61 when viewed in the direction of the axis A of the annular portion 61 (as viewed in the axial direction of the exhaust pipe 5). The point P indicates the point farthest from the straight line L on the outer peripheral surface of the annular portion 61. Hereinafter, this point is referred to as “farthest point P”. The straight line S is a common circumscribing line of the outer peripheral surfaces of the two annular portions 61. If the outer diameters of the two annular portions 61 are the same, the contact point between the outer peripheral surface of the two annular portions 61 and the common outer tangent line S coincides with the farthest point P.

  When the axis A of the two annular portions 61 is not parallel, the straight line A is a straight line passing through the centers of the two annular portions 61 when viewed in the direction of the axis A of one of the annular portions 61. . Alternatively, the straight line A is a straight line that passes through the centers of the two annular portions 61 when viewed from the direction that is closest to both the axes A of the two annular portions 61. Hereinafter, “the direction of the axis A” means the direction of the axis A of one of the annular portions 61 or the axis A of the two annular portions 61 when the axes A of the two annular portions 61 are not parallel. It shall be the direction that is closest to both. In short, the “view of the direction of the axis A” may not be strictly when viewed from the direction of the axis A, but may be when viewed from the direction in which the annular portion 61 looks circular or oval.

  The annular portion 61 is a portion having a cylindrical configuration with an inner diameter through which the exhaust pipe 5 can be inserted. The outer diameter and the axial dimension of the annular portion 61 are not particularly limited. However, the outer diameter of the annular portion 61 is preferably as small as possible from the viewpoint of space saving. For this reason, as shown in FIGS. 5 and 6, the annular portion 61 has a shape in which the radial thickness is smaller than the axial dimension, for example, a thin-walled cylinder has a larger axial dimension than the thickness. It is preferable to have a shape that is rounded so as to be.

  The two connecting portions 62 are joined to the two annular portions 61 by welding, and connect the two annular portions 61 together. Each of the two connecting portions 62 has a band plate configuration. The two connecting portions 62 are provided so as to sandwich the two annular portions 61 from both outer sides of the straight line L (that is, both outer sides in the arrangement direction of the two annular portions 61) when viewed in the direction of the axis A. And each of the two connection parts 62 is joined to each of the two annular parts 61 by welding. More specifically, one end of the connecting portion 62 in the longitudinal direction (extending direction of the straight line L) is joined to the outer peripheral surface (radially outer surface) of one annular portion 61, and the other end in the longitudinal direction. The part is joined to the outer peripheral surface of the other annular part 61. Note that, as described above, the two connecting portions 62 are configured to sandwich the two annular portions 61 from both outer sides. For this reason, both end portions in the longitudinal direction of one connecting portion 62 (joint locations (welding locations, which will be described later) with the two annular portions 61) are located on one side of the same side with respect to the straight line L.

  When the two exhaust pipes 5 are connected by such a connecting member 6, changes in the distance between the two exhaust pipes 5 and twisting deformation of the exhaust pipe 5 can be prevented or suppressed. Moreover, according to such a connection member 6, the two exhaust pipes 5 can be arranged close to each other. That is, when the annular portion 61 is provided with an extending portion extending radially outward and bolted between the extending portions, as in the conventional case, for bolting between the two exhaust pipes 5. Space is required. For this reason, a space for bolting must be secured, and the two exhaust pipes 5 cannot be brought close to each other. On the other hand, according to this embodiment, since it is not necessary to interpose another member between the two exhaust pipes 5, the two exhaust pipes 5 can be arranged close to each other. For this reason, the space required for the arrangement of the exhaust pipe 5 can be saved. Moreover, in the structure which arranges the several exhaust pipe 5 in a vehicle width direction, the two exhaust pipes 5 mutually connected can be made to approach in the vehicle width direction. For this reason, since the vehicle width direction dimension of the space in which the exhaust pipe 5 is installed can be reduced, the allowable bank angle of the motorcycle 1 can be increased. Moreover, since the restriction on the installation space of the exhaust pipe 5 is reduced, the degree of freedom in layout of the exhaust pipe 5 is improved, and the length of the exhaust pipe 5 can be increased.

  Each of the two connecting portions 62 is curved so that the intermediate portion in the longitudinal direction (that is, the portion between the two annular portions 61) approaches each other. In other words, each intermediate portion of the two connecting portions 62 is not parallel to the common outer tangent line S and is closer to the straight line L than the common outer tangent line S.

  With such a configuration, each of the two connecting portions 62 is easily elastically deformed in such a manner as to expand and contract in the extending direction of the straight line L. For this reason, when a force is applied to the two annular portions 61 so as to approach or separate from each other, each of the two connecting portions 62 expands and contracts (elastically deforms) in the extending direction of the straight line L. The force applied to the joint portion (welded portion) between the connecting portion 62 and the annular portion 61 is alleviated. Therefore, the load applied to the joint portion between the connecting portion 62 and the annular portion 61 is reduced, and breakage of the joint portion can be prevented or suppressed.

  In addition, with such a configuration, other devices and members can be arranged at locations where the connecting portion 62 is curved. Therefore, it is possible to effectively use the arrangement space of the devices and members. For example, as shown in FIG. 4, it can arrange | position so that a part of other exhaust pipe 5 may be put in the location where the connection part 62 is curving. For this reason, since the other exhaust pipes 5 can be disposed close to the two exhaust pipes 5 connected by the connecting member 6, the space for arranging the exhaust pipes 5 can be reduced.

  In addition, each of both end portions of the two connecting portions 62 is curved in an arc shape when viewed in the direction of the axis A, and on the outer peripheral surfaces of the two annular portions 61, a certain amount in the circumferential direction of the annular portion 61 is obtained. Surface contact over the length. In particular, both end portions of the two connecting members 6 are in surface contact with both sides of the farthest point P in the circumferential direction. For this reason, both the portion on the end side in the longitudinal direction from the farthest point P and the portion on the center side in the longitudinal direction from the farthest point P are superimposed on the outer peripheral surface of the annular portion 61 when viewed in the extending direction of the straight line L. To do. In order to realize such a configuration, the longitudinal dimension of each of the two coupling parts 62 (the dimension in the extending direction of the straight line L) is two contact points (the farthest point P) of the common outer tangent line S of the two annular parts 61. It is larger than the dimension between them.

  With such a configuration, when a force that approaches or leaves the two annular portions 61 is applied, the force is received at a place where the connecting portion 62 and the annular portion 61 are in surface contact. Can do. For this reason, the load concerning the junction location (welding location) of the connection part 62 and the annular part 61 can be made small. That is, if both end portions of the connecting portion 62 are not curved along the outer peripheral surface of the annular portion 61 and are not in surface contact with the outer peripheral surface of the annular portion 61, a force that moves the two annular portions 61 closer to or away from each other. Is received only at the joint portion between the connecting portion 62 and the annular portion 61. For this reason, the load applied to the joint portion between the connecting portion 62 and the annular portion 61 is increased, and it is necessary to reinforce the joint portion, for example. On the other hand, according to the present embodiment, a force that moves the two annular portions 61 closer to or away from each other is received at a location where the connecting portion 62 is in surface contact with the outer peripheral surface of the annular portion 61. The load applied to the joint portion between the portion 62 and the annular portion 61 can be reduced.

  As shown in FIGS. 5 and 6, a substantially “V” -shaped recess 621 (in other words, a cut) is formed on the end surface of the connecting member 6 in the longitudinal direction. The connecting portion 62 is joined to the annular portion 61 by welding at a portion corresponding to the two oblique sides of the “V” shape of the concave portion 621. Thus, when the substantially “V” -shaped concave portion 621 is provided on the end face in the longitudinal direction of the connecting portion 62 and the concave portion 621 is joined by welding, the width of the connecting portion 62 and the annular portion 61 is narrow. In addition, the weld bead (welding range) can be provided long without increasing the size of the joining portion (in particular, the circumferential dimension of the annular portion 61). Therefore, the joint strength can be improved (or prevented from being lowered) while saving the space at the joint. As shown in FIGS. 5 and 6, the lengths of the two hypotenuses of the “V” shape of the recess 621 are different from each other, and the positions of the end portions of the two hypotenuses (here, the circumferential position of the annular portion 61). ) Are also different from each other. According to such a configuration, the positions of the end portions of the weld beads along the two oblique sides of the “V” shape are shifted from each other in the circumferential direction of the annular portion 61, so that the load on the end portions of the beads is distributed. can do.

  In addition, as shown in FIG.5 (b), the structure by which the convex part 622 which protrudes in a substantially "V" shape may be provided in the end surface of the longitudinal direction of the connection member 6 may be sufficient. Also in this case, the connecting portion 62 is joined to the annular portion 61 by welding at portions corresponding to the two oblique sides of the “V” shape of the convex portion 622. Similarly, the lengths of the two hypotenuses of the “V” character of the convex portion 622 are different from each other, and the positions of the end portions of the two hypotenuses (here, the circumferential position of the annular portion 61) are also different from each other. Even if it is such a structure, there can exist an effect similar to the above-mentioned. In addition, the structure in which the convex part 622 is similarly provided is applicable also to the connection member 6 shown in FIG.

  Further, as shown in FIGS. 5 and 6, each of the two annular portions 61 is provided with an opening portion 611 penetrating in the radial direction at a location where the connecting portion 62 is not in surface contact. According to the configuration in which such an opening 611 is provided, the overall weight of the connecting member 6 can be reduced without causing a decrease in the bonding strength between the connecting portion 62 and the annular portion 61. Note that the specific shape and dimensions of the opening 611 are not particularly limited. For example, as shown in FIGS. 5 and 6, an elongated hole-shaped opening 611 extending in the circumferential direction of the annular portion 61 can be applied.

  The two annular portions 61 may be directly mounted on the outer peripheral surface of the exhaust pipe 5 or may be mounted via a cushioning material or the like. That is, a configuration in which a buffer material such as tubular rubber or sponge is wound around the outer peripheral surface of the exhaust pipe 5 and the annular portion 61 is mounted outside the buffer material can be applied. In this case, the cushioning material may be joined to either the outer peripheral surface of the exhaust pipe 5 or the inner peripheral surface of the annular portion 61. However, in order to allow relative displacement between the exhaust pipe 5 and the annular portion 61, it is preferable that the cushioning material is not configured to be joined to both the outer peripheral surface of the exhaust pipe 5 and the inner peripheral surface of the annular portion 61. According to such a configuration, vibration and impact can be absorbed by the cushioning material. Moreover, it can prevent or suppress that the connection member 6 moves with respect to an exhaust pipe with a buffer material.

(Exhaust pipe connection structure with connecting member)
Next, the connection structure of the exhaust pipe 5 by the connection member 6 will be described with reference to FIGS. FIGS. 7 and 8 are perspective views schematically showing a connection structure of the exhaust pipe 5 by the connection member 6. FIG. 7 shows a connection structure of two exhaust pipes 5 drawn from each of the two exhaust ports 441 closer to the center of the engine unit 4 in the vehicle width direction. FIG. 8 shows a connection structure of the two exhaust pipes 5 drawn out from the two exhaust ports 441 at both ends of the engine unit 4 in the vehicle width direction. As shown in these drawings, the plurality of exhaust pipes 5 are drawn out from each of the plurality of exhaust ports 441 and assembled in the collecting portion 51 on the downstream side of the exhaust port 441. The connecting member 6 is attached to an intermediate portion between the upstream end of the plurality of exhaust pipes 5 (that is, the end joined to the exhaust port 441 of the engine unit 4) and the downstream collecting portion 51. The exhaust pipes 5 are connected.

  Specifically, each of the two annular portions 61 of the connecting member 6 is attached to the outer periphery of the intermediate portion between the upstream end of the two exhaust pipes 5 and the collecting portion 51. The annular portion 61 is attached to the outer periphery of the exhaust pipe 5 but is not fixed to the exhaust pipe 5. For example, joining by welding etc. is not carried out. That is, the annular portion 61 can move or rotate on the outer periphery of the exhaust pipe 5 by itself. For this reason, the connecting member 6 can move relative to the exhaust pipe 5 even if it is attached to the exhaust pipe 5 as long as the axes of the two exhaust pipes 5 to be connected are parallel.

  With such a configuration, damage to the connecting member 6 and the exhaust pipe 5 can be prevented. That is, when the exhaust pipe 5 is vibrated or deformed when the annular portion 61 of the connecting member 6 is joined and fixed to the exhaust pipe 5 by welding or the like, the annular portion 61 of the exhaust pipe 5 and the connecting member 6 is used. A load is applied to the joint location (fixed location). On the other hand, according to the present embodiment, since the annular portion 61 of the connecting member 6 is not joined (fixed) to the exhaust pipe 5, even if the exhaust pipe 5 vibrates or deforms, the exhaust pipe 5 and the relative displacement between the annular portion 61 are allowed. For this reason, the load to the exhaust pipe 5 and the connecting member 6 can be reduced at the place where the connecting member 6 is provided.

  FIG. 8 shows a configuration in which the two exhaust pipes 5 are connected by a connecting member 6 at a place where the two exhaust pipes 5 are not parallel. In this case, the connecting member 6 shown in FIG. 6 is applied. When the two exhaust pipes 5 are connected at a portion that is not parallel, the connecting member 6 does not move in the axial direction of the two exhaust pipes 5. For this reason, displacement of the connecting member 6 is prevented. However, since a certain amount of relative movement is allowed, the load on the exhaust pipe 5 and the connecting member 6 can be reduced as described above.

  As mentioned above, although embodiment of this invention was described in detail with reference to drawings, the said embodiment only showed the specific example in implementation of this invention. The technical scope of the present invention is not limited to the embodiment described above. The present invention can be variously modified without departing from the spirit thereof, and these are also included in the technical scope of the present invention.

  For example, in the above-described embodiment, the configuration in which two exhaust pipes are connected by one connecting member is shown, but the number of exhaust pipes connected by one connecting member is not limited. The connection member should just be the structure which has the number of annular parts and connection parts according to the exhaust pipe to connect. In short, the connecting member may be configured to include a plurality of annular portions and connecting portions according to the exhaust pipe to be connected.

  In the above embodiment, a motorcycle to which a four-cylinder engine is applied has been described. However, the number of cylinders of the engine is not limited, and may be two cylinders, three cylinders, or five or more cylinders. In short, the engine unit may have a plurality of combustion chambers and a plurality of exhaust pipes 5 drawn from the plurality of combustion chambers. Moreover, in the said embodiment, although the on-road type motorcycle which has a twin spar frame was shown as a motorcycle, the kind of motorcycle is not specifically limited.

  The present invention is a technique effective for a connection structure of an exhaust pipe of a motorcycle. And according to this invention, the load to an exhaust pipe by a vibration can be reduced by connecting an exhaust pipe by a connection member. Further, since the exhaust pipes to be connected can be brought close to each other, space can be saved.

1: Motorcycle 223: Silencer (muffler)
4: Engine unit 41: Crankcase assembly 43: Cylinder block 44: Cylinder head 441: Exhaust port 45: Cylinder head cover 46: Oil pan 5: Exhaust pipe 51: Collecting part 6: Connecting member 61: Annular part 511: Opening part 62 : Connection part 621: Concave part 622: Convex part L: Straight line passing through the center of two annular parts S: Common circumscribed line P: Farthest point A: Axis line of annular part

Claims (10)

A connection structure for an exhaust pipe of a motorcycle having a plurality of exhaust pipes,
A connecting member that connects the plurality of adjacent exhaust pipes;
The connecting member is
An annular portion mounted without being fixed to the outer peripheral surface of each of the plurality of exhaust pipes;
A connecting portion that connects the annular portions mounted on the outer periphery of each of the plurality of adjacent exhaust pipes;
An exhaust pipe connection structure for a motorcycle, characterized by comprising: The connecting member includes two connecting portions,
The exhaust of a motorcycle according to claim 1, wherein each of the two connecting portions is joined to the two annular portions on each of both sides of a straight line passing through the center of the two annular portions. Tube connection structure.   3. The motorcycle according to claim 2, wherein each of the two connecting portions has both end portions joined to the two annular portions, and the intermediate portion is curved so as to approach each other. Exhaust pipe connection structure.   The two end portions of the two connecting portions are connected by the connecting members on the outer peripheral surfaces of the plurality of annular portions when viewed in the axial direction of the plurality of exhaust pipes connected by the connecting members. 4. The exhaust pipe connection structure for a motorcycle according to claim 2, wherein the exhaust pipe is in contact with a range including a position farthest from a straight line passing through the centers of the plurality of exhaust pipes. The connecting member includes a plurality of the annular portion and the connecting portion,
2. The exhaust pipe connection structure according to claim 1, wherein the plurality of connecting portions are arranged so as to surround an outer side of the plurality of annular portions and connect the annular portions to each other. At both ends of the connecting member, a substantially “V” -shaped recess or protrusion is provided,
The exhaust pipe connection structure of a motorcycle according to any one of claims 1 to 5, wherein the connecting member has two hypotenuses of the "V" shape welded to an outer peripheral surface of the annular portion. .   The exhaust pipe connection structure of a motorcycle according to claim 6, wherein the positions of the end portions of the welding range of the two oblique sides are different from each other when the annular portion is viewed in the axial direction.   The exhaust pipe connection structure for a motorcycle according to any one of claims 1 to 7, wherein an opening portion penetrating in a radial direction is provided in a portion of the annular portion where the connection portion does not overlap. .   The said connection member is provided in the middle of the upstream end of these exhaust pipes, and the gathering part where these exhaust pipes gather together, The any one of Claim 1 to 8 characterized by the above-mentioned. Connecting structure of exhaust pipe of motorcycle.   The exhaust pipe connection structure for a motorcycle according to any one of claims 1 to 9, wherein the connection member is provided at a position where axes of the plurality of exhaust pipes are not parallel to each other.

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