JP3330057B2 - Engine intake system for motorcycles and tricycles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a vehicle body frame,
The present invention relates to an improvement in an engine intake device for a motorcycle or a three-wheeled vehicle in which a power unit including an engine and driving wheels connected to the engine via a transmission device is supported on a body frame so as to be able to swing up and down.

[0002]

2. Description of the Related Art Conventionally, a power unit having an engine and a driving wheel connected thereto via a transmission is suspended from a body frame of a motorcycle so as to be able to swing up and down, and a carburetor in an intake passage connected to the engine is provided. In the intake system of the engine, the intake chamber is fixed to the power unit so that the intake chamber can be swung together with the power unit. Is known (see Japanese Utility Model Laid-Open No. 3-51162).

[0003]

However, in such a motorcycle intake system, the engine and the intake chamber do not move relative to each other, and no external force such as bending acts on the intake / exhaust pipe connecting them. Although it has the advantage of ensuring smooth flow and suppressing the deterioration of the intake / inlet pipe, the intake chamber swings up and down together with the power unit, so that the intake chamber interferes with the body frame and attached parts attached to it. Therefore, there is a problem that the required volume of the intake chamber is secured, the shape of the body frame, the layout of accessory parts, and the like are restricted.

The present invention has been made in view of the above circumstances, and provides an intake system for an engine in a motorcycle or a three-wheeled vehicle, which secures a necessary volume of an intake chamber and does not suffer from the above restrictions. The purpose is to do so.

[0005]

According to the first aspect of the present invention, there is provided a power unit having an engine and a drive wheel connected to the engine via a transmission device. swingably suspended vertically, the intake pipe communicated with the intake port of the engine connects the carburetor and the air cleaner sequentially, the calibration
Inlet inlet / outlet opened in the middle of the intake pipe downstream from the breather
A port, the entrance of the intake tea Nba through an intake and out tube
Formed by connecting, automatic operation two, a suction device of an engine in a tricycle, the carburetor is disposed in front of the air cleaner supported on the power unit, placing the intake chamber on the side of the carburetor, the calibration
Brackets supported on the intake pipe downstream of the breather
Ri said and the intake chamber characterized in that attached to the intake pipe, thereby, the intake chamber, the engine
The dead space on the side of the carburetor can be integrated with the power unit in front of the air cleaner while securing the necessary volume to increase the filling efficiency. Even if the power unit is fully swung, it can be installed on the body frame or on it. This avoids interference with other parts and does not limit the shape of the body frame or the layout of accessory parts. In addition, the intake chamber is connected to the intake pipe downstream of the carburetor.
Mounting reduces the number of parts and reduces cost
External force such as bending acts on the inlet / outlet pipe.
The deterioration can be suppressed without causing any deterioration.

In order to achieve the above object, according to the second aspect of the present invention, in the first aspect, the upper surface of the intake chamber is substantially at the same level as the upper surface of the air cleaner. Accordingly, the intake chamber does not protrude above the air cleaner, and the dead space in front of the air cleaner can be arranged more effectively.

[0007] is found for the purposes achieved, according to the invention of the present claim 3, in those of claim 1,
The free end portion of the front Symbol intake chamber, and characterized in that is engaged with the air cleaner, a screw member such as fittings for attaching the suction chamber with the thereby facilitating Toda' to the power unit of the intake chamber Can be reduced, which can contribute to cost reduction.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described based on embodiments of the present invention shown in the accompanying drawings.

This embodiment is an embodiment in which the present invention is applied to a two-cycle engine of a scooter type motorcycle. FIG. 1 is an overall side view of a scooter type motorcycle equipped with the present invention. 2 is a side view of the rear wheel suspension, FIG. 3 is an enlarged view of a part of FIG. 2, FIG. 4 is a cross-sectional view taken along line 4-4 in FIG. 3, and FIG. FIG. 6 is a partial longitudinal sectional view taken along line 6-6 in FIG. 4. In the following description, "front and rear" and "left and right" refer to the traveling direction of the motorcycle. .

In FIGS. 1 and 2, a front wheel Wf is steerably supported via a front fork 2 at a front portion of a body frame 1 of a scooter type motorcycle indicated by a reference symbol V, and a rear portion of the body frame 1 is provided. Has a power unit Up,
Through the arm 3 is swingably supported 3 ₁ vertically. A damper 4 is connected between a rear portion of the power unit Up and a rear portion of the vehicle body frame 1. Most of the body frame 1 is covered by a body cover 5 fixed thereto, and the body cover 5 on the power unit Up is provided.
Is provided with a luggage box 6 for storing luggage such as a helmet, and a seat 7 on which an occupant sits is mounted on the open upper surface of the luggage box 6 so as to be openable and closable. By opening the seat 7, it is possible to put the luggage in and out of the luggage box 6.

In FIG. 1, reference numeral 8 denotes a stand, and 9 denotes a luggage carrier provided at the rear of the vehicle body cover 5.

The power unit Up includes a two-stroke engine E and rear wheels, ie, drive wheels Wr, which are operatively connected to each other via a transmission T. The two-stroke engine E is a conventionally known one, and as shown in FIG.
The engine includes a cylinder 11 extending vertically and a crankcase 12 connected to a lower part of the cylinder 11. A piston 13 is fitted to the cylinder 11 so as to be slidable up and down. An intake port 14 that communicates with the crankcase 12 is formed. The intake port 14 is provided with a reed valve 16. A lower end of the intake pipe 15, that is, an upstream end, is integrally connected to an inlet of the intake port 14 by a connecting bolt 17. The air-fuel mixture flowing through the intake pipe 15 is supplied to the reed valve 16.
Is supplied through the intake port 14 to the combustion chamber of the engine E. An outer periphery of the engine body 10 is covered with a shroud 18, and an exhaust system Ex is connected to an exhaust port opened on the front surface of the engine body 10.
The exhaust system Ex extends to the rear of the engine body 10 bypassing the engine body 10.

The intake pipe 15 extends rearward upward from the front upper surface of the power unit Up, and its upper end, ie, the upstream end, is connected to the outlet of the carburetor Ca. The carburetor Ca is a power unit U
p is located above the front of p and has a conventionally known structure,
An air-fuel mixture having a necessary air-fuel ratio is generated, and the flow rate of the air-fuel mixture is adjusted by opening / closing a throttle valve provided therein and supplied to the intake pipe 15. Carburetor C
The outlet 19 of the air cleaner Ac is connected to the inlet 19 of a as usual (see FIG. 6).

The air cleaner Ac has a rectangular shape in a side view and is formed in a closed box shape that is flat in the left-right direction. The air cleaner Ac is located behind the carburetor Ca and the intake pipe 15 above the power unit Up, and has a cleaner case of the air cleaner Ac. Reference numeral 20 denotes a case body 21 formed of a synthetic resin material and having an open outer surface, and a case cover 22 which closes the opening and is bolted to the case body 21. Between them, a plate-shaped cleaner element 24 is sandwiched and fixed, and the cleaner element 24 partitions the inside of the cleaner case 20 into a clean room 25 inside and a non-clean room 26 outside. . An inlet 27 of the carburetor Ca communicates with an outlet 27 opened at the front of the clean room 25, and an inner end of an air intake tube 28 communicates with a rear portion of the unclean room 26. The entrance of
It is opened to the atmosphere through a window hole 29 opened in the case cover 22. The case cover 22 is provided for the cleaner case 2.
It has an extension portion 22 ₁ extending in front of the lower half of the front of 0, the extension portion 22 ₁ covers the outer surface of the carburetor Ca.

As shown most clearly in FIG.
An intake port 31 is opened in the middle of an intake pipe 15 that communicates the intake port 14 with the outlet of the carburetor Ca. The intake port 31 is connected to an intake chamber Cm via an intake port 32 made of a rubber tube. Doorway 33
When the engine E is operating, the intake pipe 1
A part of the intake air flowing through 5 enters and exits the intake chamber Cm. As shown in FIGS. 3 and 4, the intake chamber Cm is flat in the vertical direction, is long in the front-rear direction, and is formed in a V-shape in plan view, and has a volume necessary to increase the charging efficiency of the engine E. The carburetor Ca is arranged in front of the air cleaner Ac so as to surround the carburetor Ca. The front half 34 extends in the left-right direction, and the rear half 35 extends in the front-rear direction. The upper surface of the intake chamber Cm is substantially flat and substantially at the same level as the upper surface of the air cleaner Ac, and the rear half 35 is extended toward the front of the air cleaner Ac. The outer side surface and the outer side surface of the air cleaner Ac form a substantially continuous surface, and are located inside the vehicle body cover 5.

As clearly shown in FIG. 3, the intake chamber Cm
A bracket 36 is integrally extended downward from a front portion of the bottom wall of the bracket, and the bracket 36 is bolted 39 to the intake pipe 15 and is supported by the intake pipe 15. Also as clearly shown in FIG. 6, the bottom wall rear portion of the intake chamber Cm are extended integrally stay 37 which is bent in an L shape downwards, the tip portion 37 ₁ extending in the transverse direction of the stay 37, The fork-shaped engaging portion 38 integrally provided on the front wall of the air cleaner Ac is engaged with the fork-shaped engaging portion 38 so as to be detachable. Therefore, the intake chamber Cm is integrally supported by the intake pipe 15 and the air cleaner Ac, and swings up and down together with the power unit Up.

Next, the operation of this embodiment will be described.

Now, in order to operate the motorcycle, the engine E
When the piston 13 is driven, in the rising compression and suction process of the piston 13, the air adjusted by the carburetor Ca
From there, the fuel-air mixture flows into the crankcase 12 through the intake pipe 15 and the opened reed valve 16. By the way, when the pressure inside the crankcase 12 becomes positive after the end of this step, the reed valve 16 is closed, so that the intake pipe 15 is closed.
The flow of the air-fuel mixture inside the air-fuel mixture is temporarily stopped, and the inertia of the air-fuel mixture increases the pressure in the downstream portion of the intake pipe 15. It flows into Cm and is stored there. When the reed valve 16 is opened by the negative pressure in the crankcase 12 in the next compression and suction process, the air-fuel mixture in the intake chamber Cm passes through the intake port 32 and returns to the intake pipe 1.
5, is combined with the air-fuel mixture from the carburetor Ca, and is sucked into the combustion chamber of the cylinder 11. Thereby, the charging efficiency of the air-fuel mixture can be improved.

[0019] When the power unit Up by the traveling of the motorcycle V swing up and down around the support 3 ₁ point,
The intake pipe 15, the intake chamber Cm, the carburetor, and the air cleaner Ac move up and down together with the power unit Up. Since the upper surface is substantially the same level as the upper surface of the carburetor Ca and does not protrude upward, the power unit Up does not interfere with the vehicle body frame 1 or the components attached thereto even when the power unit Up fully swings. Further, since there is no relative motion between the engine E and the intake chamber Cm, the deterioration can be suppressed without applying a bending load to the intake inlet / outlet pipe 32 connecting them. Further, since the intake chamber Cm is attached to the intake pipe 15, there is no need to specially provide a bracket for attaching the intake chamber Cm to the vehicle body frame 1, and the number of parts can be reduced to contribute to cost reduction. Since the intake chamber Cm is positioned by being detachably engaged with the engaging portion 38 formed on the air cleaner Ac, positioning components such as screws are not required, and removal thereof is facilitated.

Next, a first modified example of the present invention will be described with reference to FIG. 7. FIG. 7 is a partial plan view of a power unit having an intake chamber Cm showing the modified example. The same members as those in the embodiment are denoted by the same reference numerals. In the first modified example, the shape and arrangement of the intake chamber Cm are different from those of the above-described embodiment, and the intake chamber Cm in front of the air cleaner Ac and on one side of the carburetor Ca is the same as that of the above-described embodiment. As in the case of the first embodiment, it is formed in a rectangular shape in a plan view, is disposed symmetrically with respect to the above-mentioned embodiment, and its rear half 35 extends to the right of the carburetor Ca. Although not shown, this intake chamber Cm
Is on the same level as the air cleaner Ac, as in the previous embodiment.

The first modified example has the same operation and effect as those of the first embodiment.

Next, a second modification of the present invention will be described with reference to FIG. 8. FIG. 8 is a partial plan view of a power unit having an intake chamber Cm, showing the modification. The same members as those in the embodiment are denoted by the same reference numerals. In the second modified example, the shape and arrangement of the intake chamber Cm are different from those of the above-described embodiment, and the intake chamber Cm in front of the air cleaner Ac and on one side of the carburetor Ca is opened rearward in plan view. The left and right rear half portions 35 are formed symmetrically and extend to both left and right sides of the carburetor Ca. Although not shown, the upper surface of the intake chamber Cm is at substantially the same level as the air cleaner Ac, as in the previous embodiment.

The second modified example has the same operation and effect as those of the above-described embodiment.

Although one embodiment of the present invention has been described above, the present invention is not limited to the embodiment, and various embodiments are possible within the scope of the present invention. For example, in the above-described embodiment, the case where the present invention is applied to a two-cycle engine has been described. However, the present invention can also be applied to a four-cycle engine, and the intake chamber is provided in another part such as a power unit transmission case. May be attached. Also,
In the above embodiment, the intake chamber is formed of a synthetic resin material, but may be formed of another material.

[0025]

According to the first aspect of the present invention, the vehicle body
Connected to the engine via an engine and transmission
Swing up and down a power unit with driving wheels
Intake that is suspended as much as possible and communicates with the intake port of the engine
Connect the carburetor and air cleaner to the pipe in order.
Of the engine intake system for motorcycles and motorcycles
And opened in the middle of the intake pipe downstream of the carburetor
The intake chamber is connected to the intake port via the intake port.
Connect the inlet and outlet, the carburetor is disposed in front of the air cleaner supported on the power unit, placing the intake chamber on the side of the carburetor, the cab
With a bracket supported on the intake pipe downstream of the letter
Since the intake chamber is attached to the intake pipe, the intake chamber is provided integrally with the power unit using the dead space on the side of the carburetor in front of the air cleaner while securing a volume necessary for increasing the filling efficiency of the engine. Therefore, even when the power unit swings full, interference with the vehicle body frame and the components attached thereto can be avoided, and there is no restriction on the shape of the vehicle body frame and the layout of the accessory parts. Carburetor for intake chamber
ー The number of parts can be reduced
Reduction contributes to cost reduction, and furthermore, the intake / inlet pipe is bent.
The deterioration should be suppressed without external force such as
Can be.

[0026] According to the invention of the present claim 2, the upper surface of the air intake chamber, since the air cleaner and the top surface and substantially the same level, the intake chamber of the air cleaner in front of dead space without protruding above the air cleaner It can be used more effectively and arranged.

[0027] According to the or the invention of this third aspect, the free end portion of the air intake chamber, so was locked to the air cleaner, the intake chamber while facilitating Toda' to the power unit of the intake chamber Mounting parts such as screw members for mounting can be reduced, which can contribute to cost reduction.

[Brief description of the drawings]

FIG. 1 is an overall side view of a scooter type motorcycle.

FIG. 2 is a side view of a rear wheel suspension unit of the motorcycle.

FIG. 3 is an enlarged view of a part of FIG. 2;

FIG. 4 is a cross-sectional view taken along line 4-4 in FIG. 3;

FIG. 5 is a partial longitudinal sectional view taken along line 5-5 in FIG. 4;

FIG. 6 is a partial longitudinal sectional view taken along line 6-6 in FIG. 4;

FIG. 7 is a plan view of a power unit having an intake chamber (first modified example).

FIG. 8 is a plan view of a power unit having an intake chamber (second modified example).

[Explanation of symbols]

1 Body frame 15 Inlet pipe 31 Inlet port 32 Inlet port 33 Inlet 36 Bracket Ac Air cleaner Ca ···· Carburetor Cm ···· Intake chamber E ····· Engine T ····· Transmission device Up ···· Power unit Wr ···· Rear wheel (drive wheel)

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F02B 27/00 F02M 35/10 F02M 35/16

Claims (3)

(57) [Claims] An engine (E) is mounted on a body frame (1).
And a power unit (Up) having a drive wheel (Wr) connected thereto via a transmission (T) so as to swing up and down, and communicate with an intake port (14) of the engine (E). A carburetor (Ca) and an air cleaner (Ac) are sequentially connected to the intake pipe (15), and the intake pipe (1 ) is located downstream of the carburetor (Ca).
5) At the intake port (31) opened in the middle of
Inlet / outlet of the suction chamber (Cm) via the inlet / outlet pipe (32)
Formed by connecting (33), automatic operation two, a suction device of an engine in a tricycle, the place carburetor (Ca) in front of the air cleaner (Ac) which is supported by the upper power unit (Up), the carburetor (Ca), the intake chamber (Cm) is arranged beside the carburetor (Ca).
To the bracket (36) supported by the intake pipe (15) on the downstream side
From the intake chamber (Cm) to the intake pipe (15).
An engine intake system for motorcycles and motorcycles, characterized by the fact that they are attached . 2. The engine intake system according to claim 1, wherein the upper surface of the intake chamber (Cm) is substantially at the same level as the upper surface of the air cleaner (Ac). 3. An engine intake system for a motorcycle according to claim 1, wherein a free end of said intake chamber (Cm) is engaged with said air cleaner (Ac).