JPH0530674B2 - - Google Patents

Description

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

(Prior Art) In a motorcycle in which a swingable power unit is pivotally supported on the body, the frame member of the body and the power unit are vertically spaced apart, as seen in Japanese Patent Laid-Open No. 57-114769. , a carburetor and an air cleaner 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 placed above the carburetor or at the rear where it has a large swing width.
There is a problem where a large, high-performance cleaner element cannot be used. 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 part is located between the rear wheels and the power unit is swingably supported on the vehicle body, an air cleaner case is arranged in front of the transmission case of the power unit and to the side of the engine part. , characterized in that the total height of the air cleaner case is formed to approximate the total height of the power unit.

(Function) With the above configuration, the size of the air cleaner case can be made approximately the same as the size of the side surface of the engine section in front of the transmission case, and a large-volume air cleaner case can be used. Since the air cleaner case is located on the pivot side of the power unit, the range of swing associated with the swing of the power unit is small, and thus the minimum ground clearance of the air cleaner case and the power unit can be easily adjusted to the desired range. Can be secured.

(Example) Next, the present invention will be explained with reference to the illustrated example. In the drawings, reference numeral 1 denotes 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 is designed to have 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.

Here, 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 parts extend rearward from the shaft support 1a above the intermediate portion. The carburetor 17 is placed in a position facing between the rear forks 1b, 1b as a frame member, and the carburetor 17 can be moved up and down between the rear forks 1b, 1b, thus making the minimum ground height of the power unit 9 relatively high. Even if set, the carburetor 17 will not move up and down between the rear forks 1b and 1b and will not 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, 20 is the cylinder part 9 of the power unit 9.
A shows a control box for the starting intake system, that is, a bistarter, installed between the air cleaner case 15 and one of the pair of air outlets 15c, 15c for the bistarter formed in the air cleaner case 15. The secondary air inlet 20a of the box 20 and the other end are connected to the mixture inlet 17b of the box 20 via the bi-starter mixture generating section 17a of the carburetor 17, and the The outlet 20c is connected to the intake pipe 8 side, and a control valve 20e that moves on a bimetal 20d housed in the box 20 automatically increases or decreases the concentration of the intake air-fuel mixture at the time of starting the engine according to the engine temperature. did.

In the drawing, 11 is the cylinder part 9 of the power unit 9.
A muffler is connected to an exhaust port 22 formed on the lower surface of a through 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, reference numerals 28 and 29 indicate a ratchet-type one-way latch for starting the engine and a generator, and reference numeral 30 indicates a chain cover. As described above, according to the present invention, the carburetor is arranged above the middle part of the power unit so as to face between a pair of left and right rear forks, and the carburetor is surrounded from above and below by both rear forks and the power unit. protected against foreign objects. The rear fork 1b
If the vertical width of the carburetor 17 is increased or a reinforcing plate is attached to increase its strength, the protection area for the carburetor 17 will also become wider.

Moreover, the carburetor 17 is connected to both rear forks 1b,
Since it is made to swing up and down between 1b,
The installation height of the power unit 9 can be easily set while avoiding interference with the rear fork 1b, and the air cleaner case 15 is placed close to the pivot point at the front of the power unit 9, and the air cleaner case 15 is placed close to the pivot point at the front of the power unit 9, and the air cleaner case 15 is placed close to the pivot point at the front of the power unit 9. Since the heights are similar, when the power unit 9 swings up and down, the swinging distance is small and there is sufficient space between it and the car body, so there is no risk of interference with the car body, and the large volume filters. A high capacity air cleaner case can be installed.

(Effects of the Invention) As described above, the present invention installs the air cleaner case on the front side of the power unit and makes its overall height similar to that of the power unit, compared to the conventional case installed at the rear of the top of the engine. Since the swing distance is short, there is no risk of interference with the upper vehicle body, and there is an advantage that a large air cleaner case can be used. This allows the power unit to be installed relatively above, making it easier to secure the lowest ground floor and allowing the use of elements with a large filtration capacity.

[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 taken 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, 17... Carburetor.

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, the air cleaner case is arranged in front of the transmission case of the power unit and to the side of the engine part, and the total height of the air cleaner case is formed to approximate the total height of the power unit. An intake device for a motorcycle, which is characterized by: