JPH02216384A - Motorcycle - Google Patents

Abstract

PURPOSE:To contrive the reduction of exhaust resistance and the improvement of a shock absorbing effect by connecting to a rear part engine block of a V-engine rear part exhaust pipes detouring around a shock absorber provided between an upper part of swing arms, journalling a rear wheel, and a car body frame. CONSTITUTION:A car body frame B mounts a V-engine E provided with front and rear part engine blocks EBf, EBr. While the car body frame B vertically swingably supports swing arms Rf journalling a rear wheel Wr. In the above constitution, the rear part engine block EBr connects a plural number of rear part exhaust pipes 30, 31 extended behind a car body detouring around a side part of shock absorbers 10 respectively arranged between an upper part of the swing arms Rf and the car body frame B. Thus, each rear part exhaust pipe 30, 31 is linearly extended reducing exhaust resistance. While the shock absorber 10 is sufficiently ensured in its length with no interference with each rear part exhaust pipe 30, 31, improving a shock absorbing effect.

Description

[Detailed Description of the Invention] A1 Object of the Invention (1) Industrial Application Field The present invention has a vehicle body frame equipped with a V-type engine having a V-shape in side view and having front and rear engine blocks. The present invention relates to a motorcycle in which a swing arm having a wheel mounted thereon is supported so as to be swingable up and down.

(2) Prior art The above-mentioned motorcycle is conventionally known as disclosed in, for example, Japanese Utility Model Application Publication No. 54-51143.

(3) Problems to be Solved by the Invention In the conventional motorcycle described above, the rear exhaust pipe connected to the rear engine block extends toward the rear of the vehicle body through the lower part of the swing arm that supports the rear wheel. This rear exhaust pipe is forced to bend sharply downward,
As a result, the exhaust resistance of the rear exhaust pipe increases, which impedes improvement in engine output. In order to prevent this, it is conceivable to extend the rear exhaust pipe linearly rearward using the space above the swing arm, but a shock absorber connecting the swing arm and the vehicle body frame is located at the top of the swing arm. Therefore, in order to avoid interference with the rear exhaust pipe, it is necessary to shorten the stroke of the shock absorber, resulting in a reduction in shock absorbing performance and a disadvantage of poor riding comfort.

The present invention has been made in view of the above-mentioned circumstances, and by rationally arranging the rear exhaust pipe connected to the rear engine block of a motorcycle equipped with a Type 2 engine and the shock absorber that suspends the rear wheel, The purpose is to ensure a sufficient stroke of the shock absorber and to reduce the exhaust resistance of the rear exhaust pipe.

B1 Structure of the Invention (1) Means for Solving the Problems In order to achieve the above object, the present invention provides a vehicle body frame with:
In a motorcycle equipped with a ■-shaped engine having a V-shape in side view and having front and rear engine blocks, the rear engine is equipped with a swing arm that supports a rear wheel so as to be swingable up and down. A rear exhaust pipe connected to the block extends toward the rear of the vehicle body, bypassing a side portion of a shock absorber provided between the upper part of the swing arm and the vehicle body frame.

(2) Effect According to the above configuration, the rear exhaust pipe connected to the rear engine block of the V-type engine avoids the shock absorber provided between the upper part of the swing arm that supports the rear wheel and the vehicle body frame. Since the shock absorber detours laterally and extends toward the rear of the vehicle body, a sufficient stroke of the shock absorber can be ensured without interfering with the rear exhaust pipe. Furthermore, since the rear exhaust pipe can be arranged in a straight line without being sharply bent, the exhaust resistance can be reduced.

(3) Embodiment Hereinafter, an embodiment of the present invention will be explained with reference to the drawings.A motorcycle includes a body frame B having a head vibrator 1 at the front end thereof, and a body frame B supported by the head vibrator 1 via a steering shaft 2. a front fork Ff that supports the moe wheel Wf;
(a power unit housed and supported within the vehicle body frame B)
P and a fork-shaped swing arm Rf that is pivotally supported at the rear of the power unit P so as to be able to swing up and down to support the rear wheel Wr.

The vehicle body frame B consists of a thin plate cowling 3 that is fixed to the front end of the head vibe 1 and extends rearward and downward, and a seat stay 4 that is separably connected to the rear end and has a channel-shaped cross section that covers the upper part of the rear wheel Wr. The cowling 3 is formed into a hollow cylindrical shape, has an air inlet 5 opened at its front end face, and an air outlet 6 opened at its rear end face, and has a streamlined shape as a whole.

Further, the cowling 3 is constructed of a lightweight plate material such as light alloy or synthetic resin, either integrally or suitably divided.

A fuel tank T is straddled over the upper part of the cowling 3,
A seat S, on which an operator rides astride, is attached to the seat stay 4 extending rearward.

The front fork Ff is configured in a telescopic pink type,
A steering handle 7 is provided at its upper end.

The power unit P is accommodated in and integrally supported within the cowling 3, and its output shaft 9 is interlocked with the rear wheel Wr via a chain transmission mechanism ch.

The swing arm Rf has two reinforcing members 34, 35 fixed to its front and rear parts, and the tops of these reinforcing members 34, 35 and the vehicle body frame B form a suspension structure with a shock absorber 10 extending diagonally forward and upward. They are connected by a mechanism Su.

Next, the configuration of the ■-type multi-cylinder engine E, which forms the main body of the power unit I-P, will be explained. This is a ■-type four-cylinder cross-flow type four-cycle engine, and
As shown in Figure 3, the vehicle body as a whole has a V-shape when viewed from the side, and has a front engine block EBf and a rear engine block EBr.
r extends toward the front of the vehicle body frame B, its cylinder center line L + L + is slightly inclined upward with respect to the horizontal plane, and the rear engine pro- nk EBr extends upward of the vehicle body frame B. It extends towards the
The cylinder centerline L x L z is inclined slightly rearward with respect to the vertical plane. A V-shaped space C that is widely open toward the head pipe 1 is formed between the front and rear engine blocks EBf and EBr.

The front and rear engine blocks EBf, EBr have front and rear cylinder blocks CBf, CBr, and front and rear cylinder heads CHf, which are polymerized and fixed to their tips, respectively.
It is composed of CHr.

The front and rear cylinder holes 13, CBf and CBr, each include two cylinders 12 arranged in parallel in the left-right direction of the vehicle body frame B, and they all have the same structure, and each cylinder hole has the same structure. The cross section of the piston 13 is oval, that is, oval, and the piston 14, which is slidably fitted therein, is naturally also formed to have an oval cross section.

Each piston 14 is connected to one crankshaft 16 via a connector rJ and a cylinder 15, respectively, as in a normal multi-cylinder engine, but in this case, each parallel cylinder cylinder J of the front and rear cylinder blocks CBf and CBr The two pistons 14 in the cylinder 12 are each 360' from each other on the crankshaft 16.
The two pistons 14 slide in synchronized reciprocation within the cylinder hole 13.

Between the front and rear cylinder heads CH4, CHr and the two pistons 14 are Ws that are parallel to each other in the left-right direction of the vehicle body.
Two combustion chambers 17 with an elliptical L cross section are formed,
In addition, those - Rad C1 (f, CHr include the combustion chamber 1
7 Each of the four intake boats 22 opens oppositely to the upper wall.
and an exhaust boat 27 are arranged in parallel, and these ports)22.
The openings on the combustion chamber 17 side of 27 become an intake valve port 18 and an exhaust valve port 19, respectively, and each intake valve port 18 has an intake valve 20 that opens and closes it, and each exhaust valve port 19 has an intake valve 20 that opens and closes it. Exhaust valves 21 that open and close are provided, respectively.

The intake valve 20 and the exhaust valve 21 are respectively linked via a valve operating mechanism (2), and the operation of the valve operating mechanism (2) opens and closes the intake valve port 1B and the υ air valve 19 at predetermined timing.

The upper surface of the front cylinder head CHf has its head CH
4 which communicates with the four intake boats 22 provided in I.
The front intake pipes 23 extend upward in a substantially straight line, and these intake pipes 23 are parallel to each other in the left-right direction of the vehicle body. Also, on the front of the rear cylinder head CHr, the head CH
4 connected to the four intake boats 22 provided in r.
The rear intake pipes 24 each extend forward and upward in a substantially straight line, and these intake pipes 24 are also parallel to each other in the left-right direction of the vehicle body. The intake port 25 at the upper end of the front intake pipe 23 and the intake port 26 at the front end of the rear intake pipe 24 extend to a point where the front and upper sides are open to facilitate intake of air, and are close to each other there. Note that although this embodiment is shown without an air cleaner, the intake port 2526
Naturally, an air cleaner can be attached to the air cleaner, and in that case, a common one can be attached to the intake ports 25 and 26. Furthermore, as is clear from FIG. 4, the intake pipe 2
3.24 vertical axes are i to each other in the lateral direction of the vehicle body frame B
IflM has been done.

As shown most clearly in FIG. 1.3, in the V-shaped space C between the front engine block EBf and the rear engine block EBr, there is a A front fuel supply device, that is, a downward ventilation type front carburetor Caf, which supplies fuel to the intake passage of The fuel supply devices, that is, the rear carburetor Car of a sideways ventilation type, are arranged opposite to each other, and the front carburetor Caf of a downward ventilation type is housed in the front half of the V-shaped space C, and Ventilation type rear carburetor Ca
r is accommodated in the latter half of the V-shaped space C.

In addition, 36 and 37 in the figure are the front and rear carburetors Ca, respectively.
The respective float chambers of f and Car are shown.

360 of the front cylinder blocks CBf are arranged in parallel with each other.
The exhaust port 27 communicating with the two cylinders 12 having an explosion interval of ° crank angle is connected to the front cylinder head CHf
4 extending downward from the lower surface of the vehicle and parallel to the left and right direction of the vehicle body.
These exhaust pipes 2 are connected to the front independent exhaust pipe 28 of the book.
8 are gathered together and communicated with one front collective exhaust pipe 29.

Similarly, an exhaust port 27 that communicates with the two cylinders 12 of the rear cylinder block CBr that are arranged in parallel with each other and has an explosion interval of 360° crank angle extends rearward from the rear surface of the rear cylinder head CHr and extends in the left-right direction of the vehicle body. It communicates with four rear independent exhaust pipes 30 arranged in parallel, and these exhaust pipes 30 are gathered together and communicated with one rear collective exhaust pipe 31.

The front independent exhaust pipe 28 and the front collective exhaust pipe 29 extend rearward at the lower part of the swing arm Rf along the bottom surface of the vehicle body frame B, and further diagonally cross the vehicle body frame B to connect the rear wheel W.
It extends rearward along the right side of r, and an exhaust muffler 32 is connected to the rear end.

Further, the rear independent exhaust pipe 30 and the rear collective exhaust pipe 31 cross the front collective exhaust pipe 29 above the power unit P and the swing arm Rf so as to cross them, and pass through the seatstay 4 to reach their ends. portion protrudes outward from the left side of the seatstay 4, and an exhaust muffler 33 is connected thereto. At this time, the rear collective exhaust pipe 31 bypasses the left side of the shock absorber 10 that connects the swing arm R'' to the vehicle body frame B, and the rear collective exhaust pipe 31 and the shock absorber 10 are overlapped in side view. This ensures a sufficiently large stroke of the shock absorber 10.Furthermore, the front exhaust pipe 28.29 and the rear exhaust pipe 30.31 utilize the lower space and upper space of the swing arm Rf, respectively, to ensure a sufficiently large stroke of the shock absorber 10. Since it extends for a long time, it can have a smooth shape without sharp bends, which can contribute to reducing exhaust resistance.

Next, to explain the operation of the above embodiment, when the engine E is driven, the power unit P is operated, and its output is transmitted from the output shaft 9 to the rear wheel W through the chain transmission mechanism ch.
transmitted to r. At this time, front cylinder block EB
The exhaust gas discharged from the four exhaust ports 27 of f is
The exhaust gas is discharged from the exhaust muffler 32 through a front independent exhaust pipe 28 and a front collective exhaust pipe 29, which are arranged substantially horizontally under the vehicle body frame B and the swing arm Rf. In addition, the exhaust gas discharged from the four exhaust ports 27 of the rear cylinder block EBr is connected to the power unit P and the swing arm Rf.
The exhaust gas is discharged from an exhaust muffler 33 through a rear independent exhaust pipe 30 and a rear collective exhaust pipe 31 which are bent slightly upward at the upper part of the exhaust pipe. Since the rear collective exhaust pipe 31 and the shock absorber IO are arranged side by side in the lateral direction so as not to interfere with each other, a sufficient stroke of the shock absorber 10 is ensured, improving riding comfort. Moreover, since the front exhaust pipes 28° 29 and the rear exhaust pipes 30, 31 are rationally arranged in the lower and upper spaces of the swing arm Rf, respectively, the bending thereof is minimized and the exhaust resistance is reduced. .

In the above embodiment, the front and rear cylinder blocks CBf
Although a V-type four-cylinder four-stroke engine having two cylinders in parallel with CBr and CBr has been described, it is clear that the number of cylinders provided in each cylinder block CBf and CBr is not limited to that in the embodiment. In addition, in the embodiment, the cylinder center line of the front engine block EBf, -L,
is tilted slightly upward with respect to the horizontal line, and the cylinder center line of the rear engine block EBr is -L,
is tilted slightly backward with respect to the vertical plane, but the rain center line L+ L+1. Lx The angle of Lx is not limited to that of the embodiment, and for example, both cylinder blocks EBf, E
It is also possible to arrange Br symmetrically in the front and back with respect to the vertical plane. Furthermore, the swing arm Rf is not limited to a fork shape, but may be a cantilever shape.

C1 Effects of the invention As described above, according to the present invention, the rear exhaust pipe connected to the rear engine block of the ■type engine has a shock absorber installed between the upper part of the swing arm that supports the rear wheel and the vehicle body frame. Since the shock absorber detours to the side and extends to the rear of the vehicle, it is possible to ensure a sufficient length of the shock absorber without interfering with the rear exhaust pipe, resulting in improved shock absorbing performance and improved riding comfort. can do. Further, since the rear exhaust pipe can be extended straight rearward without being sharply bent, the exhaust resistance thereof is reduced, which can contribute to improving the output of the engine.

[Brief explanation of the drawing]

Fig. 1 is a side view of the motorcycle of the present invention, Fig. 2 is a plan view thereof, Fig. 3 is a longitudinal sectional side view of the main part of the engine mounted on the motorcycle, and Fig. 4 is a longitudinal sectional plan view of the main part. .

Claims (1)

[Claims] Attach the front and rear engine blocks (E) to the body frame (B).
This automatic is equipped with a V-type engine (E) that has a V-shape in side view and is equipped with a swing arm (Rf) that supports the rear wheel (Wr) so that it can swing up and down. In a two-wheeled vehicle, a rear exhaust pipe (30,
31) extends toward the rear of the vehicle body, bypassing a side portion of a shock absorber (10) provided between the upper part of the swing arm (Rf) and the vehicle body frame (B).