JPS633404Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an intake structure for a motorcycle engine.

When supplying combustion air to the engine of a motorcycle, etc., the external air containing a large amount of dust is not used as is; it is passed through an air cooler element to remove dust, and then sent to a carburetor to produce gasoline. After mixing with other fuels, it is supplied to the engine.

By the way, there are cases where an air cleaner disposed at the rear of the engine is connected to a single-cylinder engine having a plurality of intake ports.
If there are no obstacles between the engine and the air cleaner, the connection can be made without any problem using a connecting tube or other connection method, but if there is a rear suspension between the two, the suspension and the connecting tube may Interference problems arise.

In particular, this problem is unavoidable when the engine, rear suspension, and air cleaner are located in the center of the vehicle width direction, and furthermore, when the engine is a single-cylinder type with multiple intake ports as described above, the intake ports are close to each other. Since these intake ports and the rear suspension overlap when viewed from the front of the vehicle, the above problem becomes conspicuous.

In order to deal with the above problem, JP-A-57-
Publication No. 15083 discloses a technology in which a chamber is placed between the engine and the rear suspension, and the engine and air cleaner are connected via this chamber. Since a new chamber is installed in a narrow space, the number of connection points between members increases, which increases the number of installation steps and causes problems such as an increased risk of air leakage.

This invention was made in view of the above circumstances,
Even though the clearance between multiple ports of a single-cylinder engine is narrow, the suspension can be placed in a position that overlaps with the port opening in the longitudinal direction of the vehicle body, and the suspension and the connecting tube can interfere with each other. Without,
It is an object of the present invention to provide an intake structure for a motorcycle engine that can maintain a smooth flow of air-fuel mixture inside a connecting tube and can solve the problems of the conventional example described above.

An embodiment of the present invention will be described below with reference to FIGS. 1 to 5. FIG. 1 is an overall view showing the general structure of an off-road motorcycle equipped with the air intake structure of the present invention.

In the figure, reference numeral 1 denotes a vehicle body frame, which is composed of a front frame 2 and a rear frame 3.
The front frame 2 includes a head tube 4, a main frame 5, a center pipe 6, and a down tube 7.
The rear frame 3 is composed of a back frame 9 and a back stay 10.

Rear fork 11 is behind the center pipe 6
is mounted so that it can rotate vertically. Further, a bracket 12 is attached to the connecting portion between the under pipe 8 and the center pipe 6, and a link mechanism 13 is attached between the bracket 12 and the rear fork 11. Furthermore, the lower end of one rear suspension 14 is rotatably attached to the link mechanism 13, and the upper end of the rear suspension 14 is rotatably attached to the rear end of the main frame 5. That is, the rear suspension 14 is disposed approximately on the central axis of the vehicle body frame 1, and the vertical rocking of the rear fork 11 is absorbed by the rear suspension 14 and the link mechanism 13. ing.

As shown in FIG. 2, an air cleaner case 15 is located between the center pipe 6 and the backstay 10 and behind the rear suspension 14.
It is screwed to a mounting portion (not shown) extending from the vehicle body frame 1 via brackets 16, 17, and 18 provided at the upper front, rear, and lower portions thereof. The air cleaner case 15 is open on one side, and the opening 19 is opened to the air cleaner case cover 15a with a seal member 20 interposed on the outer circumference thereof.
It is designed to be sealed tightly. Additionally, an opening 21 is provided at the top of the air cleaner case 15.
is formed, and an inlet tube 22 is fitted into this opening 21. The inside of the air cleaner case 15 is communicated through the inlet tube 22 with an air supply front chamber (not shown) located above the air cleaner case 15.

Further, as shown in FIG. 5, an air outlet 23 is formed on the front surface of the air cleaner case 15, and a plurality of bolt insertion holes 24 (for example, six) are formed around this air outlet 23. There is. An air cleaner unit 25 is arranged inside the air outlet 23. The air cleaner unit 25 is composed of an air cleaner element holder 26 and an air cleaner element 27.
a substrate 31 having a bent portion 28 on the outer periphery, a plurality of (for example, six) bolts 29 installed at intervals in the circumferential direction, and further having an opening 30 in the center; It consists of an air cleaner element holding part 32 attached to the rear of this board 31. Note that 33 is a drain, which is attached to the lower part of the air cleaner case 15 by a clip 34.

Further, a connecting tube 41 (hereinafter abbreviated as contube) made of a flexible material is connected to the air outlet 23 of the air cleaner case 15. The contube 41 is the only opening 4
2 and has an outwardly protruding flange 43, and two branch parts 45, 45 branched from this air introduction part 44. The front end band 46 of the branch 45 allows the rear suspension 14 to be fixed as shown in FIG.
The carburetor 47 is connected to the rear ends of left and right carburetors 47 located further forward, and the carburetors 47 are connected to both left and right intake ports provided at the rear of the single-cylinder engine.

That is, the branches 45, 45 of the contube 41
is the carburetor 4 connected to the intake port of the engine.
7 to the sides in the vehicle body width direction, extend rearward along both sides of the front rear suspension 14, and are connected to the air cleaner via an air introduction portion 44. Moreover, it overlaps with the rear suspension 14 when viewed from the front of the vehicle at the intake port opening of the engine.

A groove 48 is formed in the center of the outer circumference of the collar 43 in the width direction, and a plurality of bolt insertion holes 49 (for example, 6 holes) are formed in the center of the collar 48 in the radial direction.
) They are formed at intervals in the circumferential direction of the flange portion 43.

Contube 41 air cleaner case 1
To explain the connection structure to 5, the collar part 43
A ring-shaped plate 50 is fitted into the groove 48 such that a bolt insertion hole 51 formed in the width direction of the ring plate 50 matches a bolt insertion hole 49 of the collar portion 43 . In this state, the flange portion 43 is fitted into the bent portion 28 of the base plate 31 of the air cleaner holder 26, and the bolt 29 is inserted through the bolt insertion holes 49, 51 via the collar 52. It is designed to protrude forward. Further, these members 41, 50, and 26 are inserted into the air cleaner case 15 through the opening 19, and the collar portion 43 abuts on the inside front surface of the air cleaner case 15, and the branch portion 45 serves as an air outlet. The bolt 29 is projected forward from the bolt 23, and the tip of the bolt 29 is projected forward from the bolt insertion hole 24, and a nut 53 is screwed onto the tip of the bolt 29. That is, one side of the flange portion 43 is firmly clamped between the ring-shaped plate 50 and the air cleaner case 15, so that the contube 41 is connected to the air cleaner case 15 in a confidential manner.

Note that the rear suspension 14 is arranged between the two branch parts 45, 45 so as to be freely inserted. Further, the center pipe 6 is disposed on both outer sides of the contube 41, thereby protecting the suction system such as the contube 41 from the outside.

According to the intake structure having the above configuration, the air cleaner case 15 and the contube 41 are connected through the only relatively large opening 42, and as a result, the air inside the air cleaner case 15 flows into the contube 41. When flowing, the flow is very smooth with little fluid resistance.

Also, as mentioned above, air cleaner case 1
5 and the contube 41 are connected via a single opening 42, so that an air cleaner element 27 covering this connection opening 42 can be uniquely integrated.

Furthermore, when connecting the contube 41 to the air cleaner case 15, only one connection point is required, and therefore, the connection work is extremely easy.

Furthermore, in order to aim for high output in a motorcycle, for example, two carburetors 46 are sometimes used even in a single cylinder, but in the above intake structure, a contube 41 connected to these two carburetors 46 is used. Of course, one suspension 14 with excellent rear suspension performance is arranged behind the carburetor 46 in a small space in a well-balanced manner, and the arrangement is very excellent.

In addition, in the above embodiment, two cylinders are used in the single cylinder engine.
Although the case where there are three intake ports has been described as an example, the present invention can also be applied to an engine having three or more intake ports.

As explained above, according to the intake structure of the present invention, the independent connecting tubes are oriented laterally in the width direction of the vehicle so as to extend along both sides of the suspension so as to bypass the suspension. Even though the clearance between the multiple intake ports of a single-cylinder engine is narrow, the suspension can be positioned so that it overlaps the openings of the multiple intake ports in the longitudinal direction of the vehicle without interfering with the connecting tube. can be placed. Therefore, the suspension can be placed at the optimal position for weight balance near the center of the vehicle, and since there are no large curved parts of the connecting tube, the flow of the internal air-fuel mixture is smooth without any obstruction. It is possible to ensure a good flow. In addition, as shown in the conventional example, since no additional tube or the like is required, there are advantages in that problems such as an increase in the number of installation steps and an increase in air leakage are not caused.

[Brief explanation of the drawing]

Figure 1 is an overall view showing the schematic configuration of an off-road motorcycle equipped with the intake structure of the present invention, Figure 2 is a partially cutaway side view showing the main parts of Figure 1, and Figure 3 is Figure 2. FIG. 4 is a sectional view taken along the - line in FIG. 2, and FIG. 5 is an exploded view of the air cleaner case and contube. 1...Vehicle frame, 2...Front frame, 3
... Rear frame, 14 ... Rear suspension, 15 ... Air cleaner case, 23 ...
Air outlet, 25...Air cleaner unit, 41...Connecting tube (contube), 42...Opening, 44...Air introduction part, 4
5... branch, 47... vaporizer.

Claims (1)

[Claims for Utility Model Registration] A connecting tube that is equipped with a single-cylinder engine having a plurality of intake ports and that connects the plurality of intake ports and an air cleaner arranged at the rear of the engine independently to each intake port. a suspension is interposed between the plurality of suction ports and at least two air cleaners so as to overlap with the openings of the suction ports in the longitudinal direction of the vehicle body, and each of the connecting tubes is connected to the at least two air cleaners of the plurality of suction ports; An intake structure for an engine for a motorcycle, characterized in that the intake structure extends from the ports toward the sides in the vehicle body width direction, extends rearward along both sides of the suspension, and is connected to the air cleaner.