JPH0530675B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an air intake device for a motorcycle.

(Prior art) In a motorcycle with a swingable power unit pivotally supported at the bottom of the vehicle body, the frame member of the vehicle body and the power unit are vertically spaced apart, as seen in Japanese Patent Laid-Open No. 11476/1983. A carburetor and an air cleaner case are installed above the power unit.

(Problem to be Solved by the Invention) In the case where the carburetor and air cleaner case are disposed at the top of the engine as described above, there is a space between these parts and the rear frame for the swing stroke of the power unit. In particular, the air cleaner case is bulky and is located above the carburetor or at the rear where it has a large swing width, so a large air cleaner case cannot be used, and if a small one is used, the cleaner element In addition to high intake resistance, the cleaner element clogs quickly, requiring frequent replacement of the cleaner element.
The present invention aims to solve this problem.

(Means for Solving the Problems) The means for solving the above problems in the present invention is to configure a power unit by integrally providing a transmission case at the rear of the engine section with the cylinder center line directed in the front-rear direction, and to connect the front wheels and In a motorcycle in which the engine section is located between the rear wheels and the power unit is swingably supported on the vehicle body, an air cleaner case whose length in the vehicle width direction is smaller than the length in other directions is attached to the transmission case. It is characterized in that it is disposed along the side surface of the engine section at the front, and a cleaner element is filled in the air cleaner case substantially parallel to the side surface to allow intake air to pass in the vehicle width direction.

(Function) With the above configuration, the size of the air cleaner case seen from the side can be made approximately the same as the size of the side surface of the engine section in front of the transmission case, and the cleaner element accommodated therein has an excess area. Because it is large, it is difficult to clog and can be used for a long time, and there is little intake resistance.

(Example) Next, the present invention will be described with reference to the illustrated example. In the drawings, reference numeral 1 indicates a vehicle body or frame having a front wheel 2, a rear wheel 3, and a saddle 4 on the upper side of the intermediate portion. A chain sprocket 7 is attached to a pedal crankshaft 6 which has a rear fork 1b consisting of a rear fork 1b, and has pedal arms 5, 5 at both ends pivotally supported on the shaft support 1a. to drive the rear wheels 3, and furthermore, the vehicle body 1
A power unit 9 is mounted on the lower side of the shaft support 1a of the crankshaft 6 and extends rearwardly between the two pedal arms 5, 5.
As a result, the rear wheel 3 is freely drivable, and a pedal-equipped motorcycle is constructed as a whole.

To explain this in more detail, the power unit 9
As shown in FIG. 5, a horizontally vertical two-stroke engine is used, with the cylinder section 9a facing forward and the crankcase 9b facing rearward. A transmission case 9c is attached to the transmission case 9c, and an output shaft 11 that projects into the rear space of the crankcase 9b is attached to the rear end of the transmission case 9c.
and a drive roller 1 facing the rear wheel 3.
2, and the power unit 9
is placed between the two pedal arms 5, 5, and is pivotally supported in the front part by a hanger bolt 13 arranged in parallel to the lower side of the shaft support 1a of the pedal crankshaft 6, so as to be able to swing freely in the vertical direction. The parts are suspended by a wire-operated lifting machine 14, and the lifting machine 1
When the power unit 9 is swung upward by the operation 4, the drive roller 12 comes into pressure contact with the tire surface of the rear wheel 3, so that the power unit 9 drives the rear wheel 3.

In the drawings, reference numeral 15 indicates an air cleaner case attached to the side surface of the cylinder portion 9a of the power unit 9, and is attached in a space formed by a step between the side surface and the side surface of the crankcase 9b. The air cleaner case 15 has approximately the same overall height and longitudinal length as the cylinder part 9a, and a width smaller than these, and has the same minimum ground clearance and the highest position of the upper surface as the cylinder part 9a. A cleaner element 15A is housed inside the cylinder portion 9a in parallel with the side wall of the air cleaner case 1.
An air inlet 15a is formed at the lower part of the inner surface of the power unit 5, and an air outlet 15b is formed at the opposite side of the upper part of the air inlet 15a. An intake system path leading to the intake port 19 formed in the crankcase 9b was constructed.

According to the present invention, the carburetor 17 is supported by the power unit 9 by, for example, the connecting tube 6 and the intake pipe 8, and a pair of left and right shafts extending rearward from the shaft support 1a above the intermediate portion thereof are supported by the power unit 9, for example, by the connecting tube 6 and the intake pipe 8. The carburetor 17 is arranged at a position facing between the rear forks 1b, 1b as a frame member, and the carburetor 17 can be raised and lowered between the rear forks 1b, 1b, thereby increasing the minimum ground height of the power unit 9 relatively. Even if set, the carburetor 17 will not move up and down between the rear forks 1b and 1b and interfere with the vehicle body 1 when swinging upward.

Furthermore, in the illustrated example, the lower half of the carburetor 17 is housed in a space formed by a step between the crank case 9b and the transmission case 9c of the power unit 9, and the placement part of the carburetor 17 is The rear forks 1b, 1b and the crankcase 9b surround it from above and below, and the transmission case 9c and the rear wheel drive chain 8 surround it from the left and right, thereby improving the guarding function of the carburetor 17 against foreign objects. .

In the drawing, reference numeral 20 indicates a control box for a starting intake system, that is, a bistarter, which is attached to the cylinder portion 9a of the engine unit 9 and interposed between it and the air cleaner case 15. One of the pair of air outlets 15c, 15c is connected to the secondary air inlet 20a of the box 20, and the other is connected to the air mixture inlet 17b of the box 20 via the bi-starter mixture generating section 17a of the carburetor 17. At the same time, the outlet 20c of the box 20 is connected to the intake pipe 8 side, and a control valve 20e interlocked with a bimetal 20d housed in the box 20 adjusts the concentration of the intake air-fuel mixture to the engine temperature when starting the engine. The amount is automatically increased or decreased depending on the situation.

In the drawing, 11 is a muffler connected to an exhaust port 22 formed on the lower surface of the cylinder portion 9a of the engine unit 9 via an exhaust pipe 13, 24 is a rear fender, 25 is a fuel tank, 26 is an oil tank, 2
Reference numeral 7 indicates an oil pump provided at the rear of the transmission case 9c, 28 and 29 indicate a ratchet type one-way clutch and generator for starting the engine provided within the transmission case 9c, and 30 indicates a chain cover. In this way, according to the present invention, the carburetor is arranged above the middle part of the power unit, facing between the pair of left and right rear forks, and the carburetor is surrounded from above and below by both rear forks and the power unit. and are effectively protected from foreign objects. If the vertical width of the rear fork 1b is large or if a vertical reinforcing plate is attached to the rear fork, the carburetor 17
The range of protection for

Furthermore, since the air cleaner case 15 houses the cleaner element 15A with a large oversized area, there is little clogging even after long-term use, and there is little intake resistance.

(Effects of the Invention) As described above, the present invention uses the step formed at the front of the power unit to arrange the air cleaner case whose length in the vehicle width direction is smaller than the length in the other direction. The dead space formed at the front of the power unit can be used effectively without occupying the space where other parts can be installed at the bottom of the rear frame, unlike those installed in the air cleaner case. Since the cleaner elements are housed along the surface, cleaner elements with wide lateral surfaces can be used. Therefore, it is possible to maximize the use of a space that was previously unused for the air cleaner case.

[Brief explanation of the drawing]

Fig. 1 is a side view of an example of an engine-equipped automobile to which the device of the present invention is applied, Fig. 2 is a partially cut-away side view of its main parts, Fig. 3 is a partially cut-away front view of its main parts, and Fig. 4 is a A partially cutaway plan view of the main part, Figure 5 is the second
FIG. 2 is a plan view cut along the line V-V in the figure. DESCRIPTION OF SYMBOLS 1... Vehicle body, 1a... Shaft support, 1b... Rear fork (frame member), 2... Front wheel, 3... Rear wheel, 7... Chain sprocket, 9... Power unit, 12... Drive roller, 15...Air cleaner case, 15A...Cleaner element,
17... Vaporizer.

Claims (1)

[Claims] 1. A transmission case is integrally provided at the rear of the engine section with the cylinder centerline facing in the longitudinal direction to form a power unit, and the engine section is positioned between the front wheels and the rear wheels to allow the power unit to swing against the vehicle body. In a movably pivoted motorcycle, an air cleaner case whose length in the vehicle width direction is smaller than the length in the other direction is arranged along the side of the engine section in front of the transmission case, and the air cleaner case is placed along the side of the engine section in front of the transmission case. An air intake device for a motorcycle, characterized in that a cleaner element is filled substantially parallel to the air intake system, and the intake air is passed in the width direction of the vehicle.