JPH02216383A - Motorcycle - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] A8 Object of the invention (1) Industrial application field The present invention has a vehicle body frame equipped with a ■-shaped engine having a V-shape when viewed from the side and having front and rear engine blocks. This invention relates to a motorcycle in which a swing arm having a wheel mounted thereon is suspended so as to be able to swing 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 such a motorcycle, front and rear exhaust pipes are connected to the front and rear engine blocks of the ■-type engine, respectively. In order to avoid the attached equipment, swing arm, etc. of the engine, and to arrange it so as not to get in the way of the occupants, the engine was forced to be bent, which resulted in an increase in exhaust resistance, which hindered improvements in engine output.

The present invention has been made in view of the above-mentioned circumstances, and the present invention has been made by rationally arranging the rear exhaust pipe and the swing arm before connecting to both engine blocks of a motorcycle equipped with a V-type engine. The purpose is to reduce the exhaust resistance of the engine and improve the output of the engine.

B0 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 when viewed from the side and having front and rear engine blocks, the front engine block is equipped with a swing arm that pivots on a rear wheel and is suspended so as to be swingable up and down. A front exhaust pipe connected to the rear engine block extends rearwardly below the crankcase and swingarm of the engine, and a rear exhaust pipe connected to the rear engine block extends rearwardly below the crankcase and swingarm of the engine. It is characterized by extending rearward through the.

(2) Effect According to the above configuration, the front exhaust pipe connected to the front engine block of the ■type engine and the rear exhaust pipe connected to the rear engine block respectively pivot the rear wheels at the rear of the engine. Since the exhaust pipe extends rearward through the lower and upper parts of the swing arm, the space above and below the swing arm can be effectively utilized, and sharp bending of both exhaust pipes can be prevented as much as possible. As a result, the exhaust resistance of the exhaust pipe is reduced, making it possible to improve the engine output. (3) Embodiment An embodiment of the present invention will be explained below with reference to the drawings. a front fork Ff supported by the head vibrator 1 via a steering shaft 2 to support a front wheel Wf;
It is comprised of a power unit P housed and supported within the vehicle body frame B, 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 includes a cowling 3 made of a thin plate that faces the front end of the head vibrator L and extends rearward and downward, and a seat stay 4 with a channel-shaped cross section that is separably connected to the rear end and 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 a successor rides astride is attached to the sea 1-stay 4 extending rearward therefrom.

The front fork Ff is configured in a telescopic 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 is suspended above the cowling 3 via a suspension mechanism Su including a shock absorber 10.

Next, the configuration of the ■type multi-cylinder engine E, which forms the main body of the power unit P, will be explained.
It is a cross-flow type 4-cycle engine with 1st cylinder.
As shown in Figure 3, the vehicle 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.
extends toward the front of the vehicle body frame B, its cylinder center line, -L, is inclined slightly upward with respect to the horizontal plane, and the rear engine block EBr extends toward the top of the vehicle body frame B. The cylinder center line L2 is inclined slightly rearward with respect to the vertical plane. And front and rear engine blocks EBf, EBr
A 7-shaped space C that is widely open toward the head pipe 1 is formed between them.

The front and rear engine blocks EBf and EBr are polymerized and fixed to the front and rear cylinder blocks CBf and CBr, respectively, and the front and rear cylinder heads CHI,
It is composed of CHr.

The front and rear cylinder blocks 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 13 has a The cross section 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 connecting rod 15, as in a normal multi-cylinder engine, but in this case, two pistons in each parallel cylinder 12 of the front and rear cylinder blocks CBf, CBr. The pistons 14 are each connected to a crankshaft 16 with a crank phase angle of 360°, and the two screws 14 slide in synchronized reciprocation within the cylinder hole 13.

Between the front and rear cylinder heads C1 (f, CHr) and the two pistons 14, two combustion chambers 17 having an oval cross section and parallel to each other in the left-right direction of the vehicle body are formed.
In addition, each of the heads CHf and CHr has four intake boats 22 and an exhaust boat 27 that open oppositely to each other on the upper wall of the combustion chamber 17 and are arranged in parallel. The portions are 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]9 has an exhaust valve 21 that opens and closes it. provided.

The intake valve 20 and the exhaust valve 21 are respectively linked via a valve operating mechanism (2), and the intake valve port 18 and the exhaust valve port 19 are opened and closed at predetermined timings by the operation of the valve operating mechanism (2).

The upper surface of the front cylinder head CHI has its head C1
(Four front intake pipes 23 each communicating with the four intake boats 22 provided at f 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. The head C
Four rear intake pipes 24 each communicating with four intake boats 22 provided in the Hr 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.
So they are close to each other. Although this embodiment is shown without an air cleaner, the intake port 25.
Naturally, an air cleaner can be attached to 26, and in that case, a common one can be attached to these intake ports 25 and 26. Further, as is clear from FIG. 4, the vertical axes of the intake pipes 23 and 24 are all aligned with each other in the lateral direction of the vehicle body frame B.

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, 34 and 35 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 boat 27, which communicates with the two cylinders 12 having an explosion interval of 0 crank angle, is connected to the front cylinder hand 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 boat 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. In this way, the front exhaust pipes 28.29 and the rear exhaust pipes 30.31 extend rearward using the lower and upper spaces of the swing arm Rf, respectively, so that their shapes do not have sharp bends. It can be made smooth and 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 boats 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 boats 27 of the rear cylinder block EBr is transferred 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. In this way, said front exhaust pipe 28.29
and rear exhaust pipes 30 and 31 are swing arm Rf, respectively.
Since it is rationally arranged in the lower space and upper space of the pipe, its bending 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. Further, in the embodiment, the cylinder center line L t of the front engine block EBf
L+ is tilted slightly upward with respect to the horizontal line, and the cylinder center line L of the rear engine block EBr is
x L2 is tilted slightly backward with respect to the vertical plane, but the angles of the rain center lines L+I-r and Lz Lx are not limited to those in the example. It is also possible to arrange them symmetrically in the front and back. Furthermore, the swing arm Rf is not limited to a fork shape, but may be a cantilever shape.

Effects of the C9 Invention As described above, according to the present invention, the front exhaust pipe connected to the front engine block of the ■type engine and the rear exhaust pipe connected to the rear engine block are respectively connected to the rear exhaust pipe at the rear of the engine. Since it is installed using the space below and above the swing arm that supports the wheels, the re-exhaust pipe does not have to be bent sharply (it can be easily routed. Exhaust resistance is reduced, making it possible to improve engine output.

[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. . 28...Front independent exhaust pipe (front exhaust pipe), 29...
Front collective exhaust pipe (front exhaust pipe), 30... Rear independent exhaust pipe (rear exhaust pipe), 31... Rear collective exhaust pipe (rear exhaust pipe), B... Body frame, E...・Engine, EBf...
・Front engine block, EBr...Rear engine block, Rf...Swing arm

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 rear wheel (Wr) and a swing arm (Rf) that can swing up and down. In a motorcycle, the front engine block (EB
Front exhaust pipes (28, 29) connected to the engine (E) crankcase and swing arm (
A rear exhaust pipe (30,
31) is a motorcycle characterized in that the character 31) extends rearwardly passing above the crankcase of the engine (E) and the swing arm (Rf).