JPH031359Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] This invention relates to the arrangement structure of exhaust pipes in motorcycles, and in particular, to realize a slim body by reducing the width of the body including the exhaust pipe as much as possible. About what has been made possible. In the present invention, the side in the direction of movement of the vehicle body is defined as the front, and the opposite side is defined as the rear.

[Prior Art] One type of rear wheel suspension system for motorcycles is generally one in which the rear wheel is supported by a bifurcated fork-shaped swing arm. In the case of this rear wheel suspension system, the exhaust pipe extends rearward from the engine supported by the body frame, passes through the lower part of the body frame, wraps around the swing arm, and exits to the outside of the side of the swing arm. It is arranged to connect to the diameter muffler. A typical example of such a structure is shown in FIG. 2 by a two-dot chain line. In other words, an exhaust pipe b is arranged protruding from the swing arm a, and a muffler c is connected to the exhaust pipe b.
are disposed on the sides of the rear wheels so that they rise diagonally toward the rear, and the distance between them and the vehicle body widens toward the end. As an example of such a structure,
There is one published in Publication No. 61-182413.

Furthermore, as another type of rear wheel suspension system, one in which the rear wheel is cantilever-supported by a cantilever swing arm is also known. In this case, the swing arm and muffler are arranged in parallel with the rear wheel in between. An example of such a structure is disclosed in Japanese Patent Application Laid-open No. 129386/1986. If a single-sided swing arm is used, the rear wheel can be attached and detached from one side of the swing arm, making maintenance easier.

[Problems to be solved by the invention] The body of a two-wheeled motor vehicle is required to be as slim as possible in order to improve the left-right balance of the body and to increase the bank angle. However, in a bifurcated fork-shaped swing arm, in order to connect the exhaust pipe to the muffler located at the rear of the vehicle while avoiding interference with the vertically moving swing arm, it is necessary to connect the exhaust pipe to the outside of the side of the swing arm. The exhaust pipe must be bent significantly so that it exits. Therefore, the width of the vehicle body tends to increase due to the exhaust pipe extending to the side of the vehicle body to avoid interference with the swing arm. Also, when using a single-sided swing arm, simply placing the muffler on the opposite side of the swing arm does not make the vehicle body much slimmer. Moreover, automatic 2
The larger the displacement of a wheeled vehicle's engine, the thicker the exhaust pipe tends to be, so the placement of the exhaust pipe and muffler plays an important role in making the vehicle body slimmer.

Therefore, an object of the present invention is to provide a two-wheeled motor vehicle in which an exhaust pipe is arranged so that the width of the vehicle body can be made as narrow as possible to realize a slim vehicle body.

[Means for Solving the Problems] The motorcycle of the present invention has the following configuration.
That is, the front end is pivotally attached to the rear part of the vehicle body frame, a curved part is provided behind the pivot part to form a housing space for the rear wheel, and the swing part supports the rear wheel cantileverly on one side of the rear end. A two-wheeled motor vehicle comprising an arm, an exhaust pipe extending rearward from an engine supported by the body frame and disposed on the opposite side of the swing arm across the rear wheel, and a muffler connected to the rear thereof. , the exhaust pipe has a bent part bent upward from the lower part of the vehicle body frame, and at least a part of the bent part or the muffler connected to the bent part extends into a space behind the bent part of the swing arm. It is characterized by being arranged so that it enters the room.

[Operation of the invention] The motorcycle according to the invention employs a cantilevered swing arm. On the other hand, the exhaust pipe and muffler that extend rearward from the engine are arranged on the opposite side of the swing arm across the rear wheel. The exhaust pipe is also provided with a bent portion that passes through the lower part of the vehicle body frame and is bent upward from behind the pivoting portion of the swing arm. Therefore, when the vehicle body frame is viewed from the side, the bent portion of the exhaust pipe and the muffler are arranged obliquely to the swing arm. Furthermore, at least the bent portion or a portion of the muffler connected thereto is located within the space behind the bent portion of the swing arm. Therefore, the exhaust pipe and muffler are arranged close to the center of the vehicle body.

[Example] An embodiment of the present invention is shown in FIGS. 1 and 2.

FIG. 1 shows a right side view of a rear wheel suspension system of a motorcycle. In other words, the engine E and the transmission M are configured in a V-shape on the vehicle body frame F.
A power unit consisting of is supported. Further, a cantilevered swing arm 1 having one end pivotally connected by a pivot P is provided at the rear of the vehicle body frame. A curved space as described later is formed on the pivot P side of the swing arm 1, and a cushion unit 2 is vertically arranged in this space. The upper end of the cushion unit 2 is a cushion bracket B that is integrally formed to protrude from the vehicle body frame F.
The lower end is pivotally connected to a bracket 4 formed at the bottom of the swing arm 1 via a link rod 3. A rear wheel 6 is supported at the other end of the swing arm 1 via an axle 5. The axle 5 is hollow and bolted to a hub 8 of a rear wheel 6 at a flange 7 formed at one end thereof. Note that the reference numeral 9 in the figure is a spoke.

Further, a plurality of exhaust pipes 10 extend from an exhaust port (not shown) of the engine E, and these exhaust pipes 10 are collected in a collection part 11 disposed below the transmission M.
Furthermore, a collective exhaust pipe 12 extends rearward from the collective part 11, and a muffler 13 is provided at the rear end. Although not shown, the muffler 13 is supported by the vehicle body frame F via a bracket. As is clear from this figure, the collective exhaust pipe 12 passes through the lower part of the vehicle body, and has a bent portion 1 below and to the rear of the pivot point connected by the pivot P.
It has 2a. The bent portion 12a is a portion that rises obliquely backward and upward, crosses the swing arm 1 obliquely, and connects to the muffler 13. The muffler 13 is disposed above the side of the rear wheel 6.

FIG. 2 shows a horizontal cross section of the swing arm 1 in FIG. 1 taken in the length direction. However, the direction of travel is opposite to that in Figure 1, and the left side of the figure is the front. The swing arm 1 is a cast product made of a light alloy such as aluminum and has a generally Y-shape when viewed from above, and has pivot mounting portions 14a and 14b at the tips of arm portions 1a and 1b provided on the left and right front sides. A space 1c in the curved portion surrounded by the arm portions 1a and 1b is a space in which the cushion unit 2 is disposed. In this figure, the cushion unit 2 is shown by imaginary lines. Furthermore, the curved portion 1d at the rear of the mounting portion 14b where the arm portion 1b is integrated with the same 1a is curved to the side of the arm portion 1a so as to avoid the center line O of the vehicle body in the middle thereof,
It forms a space 1e. Inside this space 1e is a rear wheel 6 that is pivotally supported on the rear end of the swing arm 1.
It accommodates. From the exhaust pipe gathering part 11 provided below the pivot mounting parts 14a, b,
A collective exhaust pipe 12, which has a large diameter to accommodate a large displacement engine, extends rearward. Although the collective exhaust pipe 12 is disposed so as to overlap under the arm portion 1b, since the distance between the two in the vertical direction is large, they do not interfere with each other. Furthermore, collective exhaust pipe 1
2 is bent upward and stands up in a space 1e formed at the rear of the arm portion 1b. Therefore, a part of this bent portion 12a is located along an imaginary line L extending rearward from the outermost portion of the pivot mounting portion 14b.
It's getting inside. Further, the upper portion of the bent portion 12a is again folded back in the horizontal direction and connected to the muffler 13 (see FIG. 1). As described above, since the cantilevered swing arm 1 is employed in this embodiment, the conventional swing arm a shown by the two-dot chain line is not required on the muffler side. As a result, in order to avoid this swing arm a, there is no need to arrange the exhaust pipe b and the muffler c to project outward. Therefore, it is clear that the distance D ₁ between the vehicle body center line O and the outside of the muffler 13 in this embodiment is smaller than the similar distance D ₂ in the muffler c of the conventional example. The exhaust pipe 12 and the muffler 13 can be placed closer to the center of the vehicle body. Note that in this embodiment, the muffler 13 is disposed above the side of the rear wheel 6, so even if the muffler 13 with a larger diameter protrudes to the side, the influence on the bank angle is less than the influence exerted by the collective exhaust pipe 12. There are also few.

Furthermore, based on FIG. 2, the structure of the cantilever type swing arm 1 in this embodiment will be outlined. A holder 15 is provided at one end of the swing arm 1.
A sprocket 16 is provided on this left side surface, and a shock absorber 17 is further attached to the outside. The shock absorber 17 is for buffering the driving force transmission shock. A known eccentric unit 18 for adjusting the position of the axle 5 in the longitudinal direction is provided in the holder 15, and an adjustment hole 18a thereof is visible in an elongated hole 19 formed in the circumferential direction of the holder 15. The axle 5 is eccentrically supported by the eccentric unit 18. Axle 5
is a hollow member formed with steps into a tapered shape,
The tip 5a penetrates the shock absorber 17 and protrudes to the other side,
Here, it is fastened with a nut 5b. The tapered shape of the axle 5 facilitates the installation work of the axle 5 by centering it and providing a guide when passing through the eccentric unit 18 and the shock absorber 17. Further, a flange 7 is integrally formed on the other end side of the axle 5. A predetermined number of bolts 20 are provided on the flange 7 at equal intervals on a concentric circle, and thereby the rear wheel 6
The spokes 9 are attached to the hub 8 formed at the center. That is, a recess 21 is formed in the hub 8, and a nut 22 is housed in the recess 21. By fastening the nut 22 to the tip of the bolt 20, the rear wheel 6 and the axle 5 are integrally attached. Therefore, the rear wheel 6 can be attached and detached only from one side of the swing arm 1 on the flange 7 side (the upper side in the figure). Further, a brake disc 25 is fixed to the flange 7 by bolts 23 and nuts 24. Further, a caliper 26 is provided at the rear of the axle 5, sandwiching the brake disc 25 therebetween. Reference numeral 27 in FIG. 2 is a boss portion integrally formed on the swing arm 1 to which one end of a torque rod (not shown) that supports the caliper 26 is attached.

Next, other embodiments are shown in FIGS. 3 and 4. The same parts as those in the previous embodiment will be given the same reference numerals and will not be described. This embodiment differs from the previous embodiment in that the muffler 30 is disposed at a lower position on the side of the rear wheel 6 and that the shape of the muffler 30 has been devised. That is, a collective exhaust pipe 12 extending rearward from a collective chamber 11 located below the vehicle body.
A bent portion 12a that bends upward is formed below the swing arm 1 near the pivot point of the pivot P. A rear end portion of the bent portion 12a is connected to the muffler 30 at a position below the swing arm 1. Therefore, the muffler 30 is provided diagonally on the side surface of the rear wheel 6 from slightly below the center to slightly above the center.
and are arranged diagonally. Also, the muffler 30 is the fourth
As shown in the figure, it has a semicircular cross section with the side surface 31 of the rear wheel 6 as a plane. In this embodiment as well, the muffler 30 is disposed such that the center side of the vehicle body enters within the rear extension line (see FIG. 2) of the arm portion 1b. Therefore, the center of the muffler 30 can be brought closer to the rear wheel 6. Therefore, even if the muffler 30 is installed at a slightly lower position, the collective exhaust pipe 12
Since the angle θ at which the vehicle body can be tilted until the bent portion 12a touches the ground can be reduced, the vehicle body can be slimmed down, and as a result, the bank angle can be increased. Therefore, the mounting position of the muffler 30 can be lowered.

Note that the present invention is not limited to the above-mentioned embodiments, and various modifications and applications are possible.

[Effects of the invention] The motorcycle according to the invention employs a cantilevered swing arm, and the exhaust pipe disposed on the opposite side of the swing arm across the rear wheel is diagonally connected to the swing arm. It has an intersecting bend. Further, at least a portion of the bent portion or the muffler enters into the space behind the curved portion of the swing arm. Therefore, the exhaust pipe can be placed as close as possible to the center line of the vehicle body. As a result, it is possible to improve the left-right balance of the car body, create a slimmer car body, and increase the bank angle.

[Brief explanation of drawings]

Figures 1 and 2 relate to the first embodiment, Figures 3 and 4 relate to the second embodiment, and Figure 1 is the right side in the traveling direction showing the rear wheel suspension part of the motorcycle. figure,
2 is an enlarged sectional view of the main part, FIG. 3 is a right side view of the main part in the direction of movement, and FIG. 4 is a side view in the Z direction of FIG. 3. Explanation of symbols, O... Vehicle center line, L... Outermost rear extension line of pivot joint, 1... Swing arm, 1b
...Curved portion, 1e... Space, 14a, b... Pivot mounting portion, 5... Axle, 6... Rear wheel, 10...
Exhaust pipe, 11...Collection part, 12...Collection exhaust pipe,
12a...bending portion, 13...muffler.

Claims (1)

[Scope of utility model registration request] a swing arm having a front end pivotally attached to a rear part of the vehicle body frame and having a curved part behind the pivoting part for forming a housing space for the rear wheel; In the motorcycle, the exhaust pipe includes an exhaust pipe extending rearward from the engine supported by the body frame and disposed on the opposite side of the swing arm across the rear wheel, and a muffler connected to the rear of the exhaust pipe. The pipe has a bent portion bent upward from the lower part of the vehicle body frame, and at least a portion of the bent portion or the muffler connected to the bent portion enters a space behind the bent portion of the swing arm. A two-wheeled motor vehicle characterized by being located at.