JPH02216379A - Motorcycle - Google Patents

Abstract

PURPOSE:To efficiently introduce cooling air by forming a front fork of an upper part pipe of large size and a lower part pipe of small size arranging in its behind an air introducing port formed in an engine cover member. CONSTITUTION:A car body frame B arranges in its front part a telescopic type front fork Ff steerably supporting a front wheel Wf. In the rear of the front fork Ff, an air introducing port 5 is opened in the front part of a cover member 3 coating an engine E in its outer side. In the above constitution, the front fork Ff is formed of a large size upper part pipe 36 pivotally supported to a car body frame B and a small size lower part pipe 37 journalling the front wheel Wf. And the air introducing port 5 of the cover member 3 is arranged behind in the small size lower part pipe 37. In this way, cooling air is efficiently introduced to the air introducing port 5 thus improving cooling performance of the engine E.

Description

Detailed Description of the Invention A0 Object of the Invention (1) Industrial Field of Application The present invention is provided with a telescopic front fork that supports a front wheel in a steerable manner at the front of a vehicle body, and an engine located behind the front fork. This invention relates to a motorcycle in which an air inlet is provided on the front surface of a cover member that covers the outside of the motorcycle.

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

(3) Problems to be Solved by the Invention In such motorcycles, the engine is cooled by introducing cooling air into the cover member from an air inlet provided in the cover member. Since the telescopic front fork located at the front is composed of a small-diameter upper pipe and a large-diameter lower pipe, the air inlet is blocked by the large-diameter lower pipe, and the cooling air is sufficiently distributed through the cover member. There was an inconvenience that it could not be introduced internally.

The present invention was made in view of the above-mentioned circumstances, and an object of the present invention is to efficiently introduce cooling air into the air inlet of a cover member located at the rear of a telescopic front fork, thereby improving engine cooling performance. shall be.

B1 Structure of the Invention (1) Means for Solving the Problems In order to achieve the above object, the present invention includes a telescopic pink type front fork that supports a front wheel in a steerable manner at the front part of a vehicle body frame, and the front fork. A motorcycle having an air inlet in front of a cover member that covers the outside of the engine at the rear of the motorcycle, a large-diameter upper pipe that pivotally supports the front fork on the body frame, and a small-diameter lower pipe that pivots the front wheel. The air inlet of the cover member is located behind the small-diameter lower pipe.

(2) Effect According to the above configuration, the telescopic front fork is composed of a large-diameter upper pipe and a small-diameter lower pipe, and the air inlet of the cover member is provided at the rear of the small-diameter lower pipe. Therefore, the flow of the cooling air is less likely to be obstructed, and the cooling air is efficiently guided into the interior of the cover member from the air inlet to cool the engine.

(3) Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings.A motorcycle has a body frame B having a head pipe 1 at the front end thereof, and is supported by the head pipe 1 via a steering shaft 2. a front fork Ff that supports the 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 a rear wheel W''.

The vehicle body frame B includes a cowling 3 made of a thin plate that is fixed to the front end of the head pipe 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 and covers the upper part of the rear wheel Wr. That cowling 3
is formed into a hollow cylindrical shape, an air inlet 5 is opened at its front end face, and an air outlet 6 is opened at its rear end face, and the whole has a streamlined shape.

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 includes left and right handles 7 and a top ring 3 fixed to both upper and lower ends of the steering shaft 2.
4 and a large-diameter upper pipe 36 supported by the bottom bridge 35, and telescopically engaged with the lower end of the upper pipe 36 to support the front wheel W.
It consists of a small-diameter lower pipe 37 that axially supports f, and a shock absorber 38 made of a coil spring is installed between the lower end of the upper pipe 36 and the lower end of the lower vibe 37. An air inlet 5 provided at the front of the cowling 3 is opened at the rear of the small-diameter lower pipe 37.

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 Fig. 3, the vehicle body as a whole has a 7-shape when viewed from the side, and has a front engine block EBf and a rear engine block EBr, and the front engine block EBr extends toward the front of the vehicle body frame B. The rear engine block EBr extends upward of the vehicle body frame B, and its cylinder center line Lz-Lx is inclined slightly upward with respect to the horizontal plane. is tilted slightly backwards with respect to the vertical plane. And front and rear engine ports EBf, EBr
In between is Hendopifu.

A widely open V-shaped space C is formed on the first side.

The front and rear engine blocks EBf and EBr are polymerized and fixed to the front and rear two cylinder blocks CBf and CBr, respectively, and the front and rear cylinder heads CHr,
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.
Each cylinder hole 13 has an oval, countersunk, oval cross section, and the piston 14, which is slidably fitted therein, also has an oval cross section. be done.

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 the crankshaft 16 with a crank phase angle of 360°, and the two pistons 14 reciprocate in the cylinder hole 13 in synchronization.

Between the front and rear cylinder heads CHf, CHr and the two pistons 14, two combustion chambers 17 with an oval cross section are formed that are parallel to each other in the left-right direction of the vehicle body, and the heads CH[, CH" is provided with four intake boats 22 and four exhaust boats 27 that open oppositely to each other on the upper wall of the combustion chamber 17, and the openings on the combustion chamber 17 side of these boats 22.27 are An intake valve port 18 and an exhaust valve port 19 are provided, and each intake valve port 18 is provided with an intake valve 20 that opens and closes it, and each exhaust valve port 19 is provided with an exhaust valve 21 that opens and closes it.

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 CHf has its head CH
4 each communicating with the four intake boats 22 provided at f.
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 which communicates with 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 intake air.
So they are close to each other. Although this embodiment is shown without an air cleaner, the intake port 25.
Of course, 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. Also, 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! Ml 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 881, 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, 39 and 40 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.
The exhaust pipes 28 are connected to a front exhaust pipe 28 of the book, and the exhaust pipes 28 are collected together and communicated to one front eight collective exhaust pipe 29. Similarly, two rear cylinder blocks CBr are arranged in parallel with each other and have an explosion interval of 360° crank angle.
The exhaust port 27 that communicates with the two cylinders 12 communicates with four rear exhaust pipes 30 that extend rearward from the rear surface of the rear cylinder head CHr and are parallel to each other in the left-right direction of the vehicle body, and these exhaust pipes 30 are grouped together. It is communicated with one rear collective exhaust pipe 31. According to the above-described exhaust pipe routing structure, the bending of the pipe can be minimized, which can contribute to reducing exhaust resistance.

The front collective exhaust pipe 29 extends along the bottom surface of the vehicle body frame B, diagonally crosses the vehicle body frame B, and extends rearward along the right side of the rear wheel Wr, and is connected to the exhaust muffler 32 at its rear end.

The rear collective exhaust pipe 31 extends above the power unit P, intersects with the front collective exhaust pipe 29 so as to cross the power unit P, and passes through the seat stay 4 so that the end thereof is connected to the seat stay 4. Projects outward from the left side,
An exhaust muffler 33 is connected there.

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, a front fork Ff is disposed in front of an air inlet 5 formed in the front of the cowling 3 to take in cooling air from the engine E. Since the vibrator 37 is located, the flow of the cooling air is efficiently taken into the air inlet 5 with almost no obstruction, and is used to cool the engine E. At this time, a shock absorber 38 is provided at the front part of the lower vibe 37, but since this shock absorber 38 is composed of a coil spring, it has many gaps, and the flow of cooling air is affected by the shock absorber 38. There will be no impact.

In the above embodiment, the front and rear cylinder blocks CBf
Although a type 4 four-cylinder four-stroke engine having two cylinders in parallel with the CBr has been described, the number of cylinders in the engine and the arrangement of the cylinders are not limited to those in the embodiment.

Furthermore, it is clear that the engine is not limited to an air-cooled engine, but may also be a water-cooled engine equipped with a radiator inside the cowling 3.

C1 Effects of the Invention As described above, according to the present invention, a telescopic front fork located in front of an air inlet formed in a cover member covering the outside of the engine is connected to a large diameter upper pipe and a small diameter lower pipe. Since the air inlet is located behind the small-diameter lower pipe, the cooling air is efficiently taken into the air inlet with almost no obstruction to its flow, resulting in improved engine cooling performance. It becomes possible to improve the

[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. . 3... Cowling (cover member), 5... Air inlet, 36... Upper pipe, 37... Lower pipe, B
...Body frame, E...Engine, F...Front fork, wr...Front wheel

Claims (1)

[Claims] A telescopic front fork (Ff) that supports the front wheel (Wf) in a freely steerable manner is provided at the front of the vehicle body frame (B), and a cover member ( 3) in a motorcycle having an air inlet (5) in the front, the front fork (Ff) is pivoted to the body frame (B) with a large diameter upper pipe (36) and the front wheel (Wf) is attached to the shaft. It consists of a small-diameter lower pipe (37) that spans the pipe, and
A motorcycle characterized in that the air inlet (5) of the cover member (3) is located behind the small diameter lower pipe (37).