Title of Invention

"INTAKE ASSEMBLY FOR MOTORCYCLE OR THREE-WHEELED VEHICLE"

Abstract

In a motorcycle having a power unit, comprised of an engine and a drive wheel connected to the engine through a transmission, swingably mounted in a vehicle frame, an intake chamber with a branched connection to an intake pipe of the engine is laid out so that swing of the power unit is not impeded while guaranteeing sufficient capacity. | Construction ] An air cleaner Ac is attached above a power unit Up that is supported in a vehicle frame swingable in the vertical direction. A carburetor Ca is disposed in front of this air cleaner Ac, and an intake chamber Cm is arranged to the side of the carburetor Ca communicating with a middle portion of the intake pipe 15.

Full Text

[Detailed Description of the Invention] [Background of the Invention] - The present invention relates toian an intake assembly for a motorcycle or three wheeled vehicle having a power unit, comprising an engine (E), and a driving wheel connected to the engine through a transmission, vertically swingably supported on a vehicle frame. | Related Art | A conventional intake assembly for a motorcycle, having a power unit, comprising an engine and a driving wheel connected to the engine via a transmission, vertically swingably mounted in a motorcycle frame, for increasing charging efficiency of intake air communicating with an intake chamber downstream of a carburetor in an intake path connecting with the engine, is known, / for example, from Japanese Utility Model Laid Open No. Hei. 3-51162. In this - j , publication, an intake chamber is fixed to the power unit, and this intake chamber can swing integrally with the power unit. ' ' [Problems to be Solved by the Invention] In an intake assembly of a motor cycle, the engine and intake chamber are not connected together, the intake chamber swings vertically with a power unit and has an advantage that smooth flow of a mixture is guaranteed and deterioration of an intake entrance pipe is inhibited since it is not affected by external forces such as bending of the intake entrance pipe connecting the engine and the air intake. This means that the intake chamber must avoid interference with a vehicle frame and attachment part mounting the vehicle frame. Because of this, necessary secured volume of the intake chamber and the shape of the vehicle frame are limited by the layout of the attachment parts etc. The present invention has been conceived in view of the above situation, and an object of the invention is to provide an air intake assembly for a motor cycle or three wheeled vehicle that secures the necessary volume of an air intake chamber while not being subject to the above described limitation. [Means of Solving the Problems] In order to achieve the above object, according to the invention disclosed in claim 1 there is provided an air intake -assembly for a motorcycle or three wheeled vehicle having a power unit, comprising an engine, and a driving wheel connected to the engine through a transmission and being vertically swingably mounted on a vehicle frame, a carburetor and an air cleaner sequentially connected to an intake pipe that communicates with an intake port of the engine, an intake entrance pipe branching off from the middle of the intake pipe, and an intake chamber connected to the intake entrance pipe, characterized by the fact that the carburetor is disposed in front of the air cleaner supported above the power unit, and the intake chamber is disposed at the side of the carburetor. As a result, it is possible to provide the intake chamber integrally with the power unit, using a dead space in front of the air cleaner, while securing the required volume. Further, the power unit can avoid interfering with the vehicle frame or parts for attaching the vehicle frame, even if it swings to the full extent, and there are no limitations caused by the layout of attachment parts or the shape of the vehicle frame. Further, in order to achieve the above object, according to the invention disclosed in claim 2, there is provided an intake assembly for a motorcycle or three wheeled vehicle as disclosed in claim 1, wherein an upper surface of the intake chamber is at substantially the same level as an upper surface of the air cleaner. As a result, the intake chamber can be disposed using a dead space in front of an air cleaner much more effectively, without protruding above the air cleaner. Still further, in order to achieve the above object, according to the invention disclosed in claim 3, there is provided an intake assembly for a motorcycle or three wheeled vehicle as disclosed in claim 1, wherein the intake chamber is attached to the intake pipe. In this way, there is no need for components, such as brackets, etc., specially for the purpose of attaching the intake chamber, and the number of components can be reduced, contributing to reduced cost. Also, deterioration of the intake entrance pipe can be restricted without using external force such as bending of the intake entrance pipe. In order to achieve the above object, according to the invention disclosed in claim 4, there is provided the intake assembly for a motorcycle or three wheeled vehicle as disclosed in claim 1, wherein a free end of the intake chamber is engaged with the air cleaner. In this way, fitting and removal of the intake chamber to and from the power unit is made simple, and attachment components such as screws etc. for attaching the intake chamber can be removed, contributing to reducing cost. Accordingly, the present invention relates to an intake assembly for a motorcycle or three wheeled vehicle having a power unit (.Up), comprising an engine (E), and a driving wheel (Wr) connected to said engine through a transmission (T) vertically swingably mounted on a vehicle frame (1), a carburetor (Ca) and an air cleaner (Ac) sequentially connected to an intake pipe (15) that communicates with an intake port (14) of said engine (E), an intake entrance pipe (32) branching off from the middle of the intake pipe (15), and a intake chamber (Cm) connected to the intake entrance pipe (32), charcuten seed in said carburetor (Ca) is disposed in frunt me air cleaner (Ac) supported above said power unit (Up), and said intake chamber (Cm) is disposed at the side of the carburetor (Ca). BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS Fig. 1 is an overall side view of a scooter type motorcycle. Fig. 2 is a side view of the rear wheel mounting portion of a motorcycle. Fig. 3 is an enlarged drawing of part of Fig. 2. Fig. 4 is a horizontal cross sectional drawing taken along line 4-4 in Fig. 3. Fig. 5 is partial vertical cross section drawing taken along 5-5 in Fig. 4. Fig. 6 is a partial vertical cross section taken along line 6-6 in Fig. 4. Fig. 7 is a plan view of a power unit having an intake chamber. (First Modification) Fig. 8 is a plan view of a power unit having an intake chamber. (Second Modification). (Embodiment of the Invention] An embodiment of the present invention will be described below based on the attached drawings. This embodiment, for a case where the present invention has been applied to a scooter type motorcycle. Fig. 1 is an overall side drawing of a scooter type motorcycle provided with the assembly of the present invention, Fig. 2 is side view of the rear wheel mounting portion of the scooter type motorcycle, Fig. 3 is an enlarged drawing of part of Fig. 2, Fig. 4 is a horizontal cross sectional drawing taken along line 4-4 in Fig. 3. Fig. 5 is a partial vertical cross sectional drawing taken along 5-5 in Fig. 4, and Fig. 6 is a partial vertical cross section taken along line 6-6 in Fig. 4. In the following description, "lateral" and, "longitudinal", "front", "rear" etc. are with respect to the travelling direction of the motorcycle. In Fig. I and Fig. 2, a front wheel Wf is supported at a front section of the frame 1 of a scooter type motorcycle represented by symbol V, via a front fork 2, so as to be steerable. A power unit Up is attached to a rear section of the frame 1, and is supported by an arm 3, via fulcrum 3,, so as to be capable of swinging in the vertical direction. A damper 4 is connected between a rear section of this power unit Up and the frame 1. The greater part of the frame 1 is covered by a body cover 5 fixed to the frame 1, and a luggage box 6 for storing things such as a helmet is provided in the body cover 5 above the power unit Up. A rider's seat 7 is mounted on an upper surface of the opening of the luggage box 6, and can be opened or closed. Items can be put in or taken out of the luggage box 6 by opening this seat 7. In Fig. 1, 8 is a stand, and 9 is luggage carrier provided at the rear of the body cover 5. The power unit Up is comprised of a 2-cycle engine E and a rear wheel, namely a drive wheel, connected to the engine via a transmission T. The 2-cycle engine E is a conventionally known engine, and as partially shown in Fig. 5, the body of the engine 10 comprises a cylinder 11 extending in the vertical direction, and a crankcase 12 connected to a lower portion of the engine body 10. A piston 13 is contained in the cylinder 11 so as to reciprocate inside it, and an intake port 14 connecting the cylinder 11 and the crankcase 12 is formed at a wall surface of the i engine body 10. This intake port 14 has a reed valve 16. A lower end, namely an upstream end, of an intake pipe 15 is integrally connected to an inlet of the intake port 14 by a connecting bolt 17. An air fuel mixture flowing in this intake pipe 15 is supplied to a combustion chamber of the engine E through the intake port 14, by opening the reed valve 16. The outer circumference of the engine body 10 is covered by a shroud 18, and an exhaust system Ex is connected to an exhaust port opening into the front surface of the engine body 10. This exhaust system Ex goes around the engine body 10 and extends in the rear direction of the engine body 10. The intake pipe 15 runs upwards from an upper surface of a front section of the power unit Up and toward the rear. An upper end of the intake pipe 15, namely an upstream end, is connected to an entrance to the carburetor Ca. This carburetor Ca is disposed above a front section of the power unit Up and has a conventionally known structure. The carburetor forms a mixture with the necessary fuel air ratio, and supplies a regulated flow of this mixture to the intake pipe 15 by controlling opening and closing of a throttle valve provided inside the carburetor. The outlet of the air cleaner Ac is connected to an inlet of the carburetor Ca (refer to Fig. 6). The air cleaner Ac has a square shape seen from the side, and is formed in the lateral direction as a flat airtight cylinder. Above the power unit Up, the air cleaner Ac is positioned to the rear of the carburetor Ca and the intake pipe 15. A cleaner case 20 of the air cleaner Ac is formed of synthetic resin and is comprised of a case body 21 having an outer surface opening, and a case cover 22 that closes off the opening and is bolted to the case body. A platelike cleaner element 24 is sandwiched between the case body 21 and the case cover 22, and partitions the cleaner case 20 into a purified chamber 25 inside the cleaner element 24 and an unpurified chamber 26 outside the cleaner element 24. The inlet of the carburetor Ca is connected to an outlet 27 that opens into a front part of the purified chamber 25, while an inner end of an intake introduction pipe 28 is connected to a rear part of the unpurified chamber 26. An inlet of this intake introduction pipe 28 opens into the atmosphere through a window 29 opening into the case cover 22. The case cover 22 has an elongated section 22, extending forward from a lower half of the front of the cleaner case 20, and this elongated section 22, covers the outer surface of the carburetor Ca. As shown clearly in Fig. 5, an intake entrance port 31 opens into the intake pipe 15 communicating with the outlet of the carburetor Ca and the intake port 14 of the engine E, and this intake entrance port 31 is connected to an entrance 33 of the intake chamber Cm via an intake entrance pipe 32 made of a plastic tube. When the engine E is operating, some of the intake flowing in the intake pipe 15 comes and goes 'through the intake chamber Cm. As shown in Fig 3 and Fig. 4, this intake chamber Cm is flat in the vertical direction, long in the front to rear direction, and has a shape resembling a flattened V in plan view, and has the capacity necessary to increase the replenishing rate of the engine E. The intake chamber Cm is arranged in front of the air cleaner Ac and surrounds the side of the carburetor Ca. The front half 34 of the intake chamber Cm extends in the lateral direction, and the rear half 35 of the intake chamber Cm extends in the front to rear direction. An upper surface of the intake chamber Cm is substantially flat, and is at substantially the same level as the upper surface of the air cleaner Ac. The rear half 35 of the intake chamber Cm extends towards the front section of the air cleaner Ac. The outer surface of the intake chamber Cm and the outer surface of the air cleaner Ac are formed as almost connecting surfaces. The intake chamber Cm is arranged inside the body cover 5. As shown extremely clearly in Fig. 3, a bracket 36 extends generally downwards from a base wall front section of the intake chamber Cm, and this bracket 36 is bolted to the intake pipe 15 with bolts 39 and is supported by the intake pipe 15. Also, as shown clearly in Fig. 6, an L-shaped bent stay 37 extends generally downwards from a base wall rear section of the intake chamber Cm, and is positioned such that a tip portion 37, extending in a sideways direction of the stay 37 is detachably engaged with at an engagement portion 38 that is fork shaped and projects from a front wall of the air cleaner Ac. Accordingly, the intake chamber Cm is generally supported by the intake pipe 15 and the air cleaner Ac, and swings in the vertical direction together with the power unit Up. Next, the operation of the embodiment will be described. When the engine E for driving a motorbike is driven, in the compression stroke and the induction stroke where the piston 13 is rising, an air-fuel mixture that has been adjusted by the carburetor Ca is caused to flow from the carburetor Ca into the crarikcase 12 through the intake pipe 15 and the opened reed valve 16. Once this stroke has been completed, positive pressure exists inside the crankcase 12 and because the reed valve 16 is closed the flow of mixture inside the intake pipe 15 is temporarily stopped. The pressure of a downstream portion of the intake pipe 15 increases due to the inertia of pulling the mixture through, and some of the mixture in this downstream portion flows into the intake chamber Cm through the intake entrance pipe 32 and remains there. Then, in the next compression induction cycle, when the reed valve is opened by negative pressure in the crankcase 12 the mixture inside the intake chamber Cm is caused to flow into the intake pipe 15 a second time through the intake entrance pipe 32, and flows together with a mixture from the carburetor Ca to enter the combustion chamber of the cylinder 11. In this way, the efficiency of replenishing the mixture can be improved. Further, when the power unit Up swings in the vertical direction around the fulcrum 3, due to the motorcycle V moving, the intake pipe 15, intake chamber Cm, carburetor and air cleaner Ac move in the vertical direction together with the power unit Up and the intake chamber Cm is compactly housed in a dead space in front of the air cleaner Ac and to the side of the carburetor Ca. Also, the upper surface of the intake chamber Cm is at substantially the same level as the upper surface of the carburetor Ca and there is no projection upwards. This means that even if the power unit Up swings to its full extent there will be no interference with the vehicle frame 1 and components attached to the vehicle frame. Since there is no relative movement between the engine E and the intake chamber Cm there is no bending load operating on the intake entrance pipe 32 and it is possible to suppress deterioration of the intake entrance pipe 32. The intake chamber Cm is attached to the intake pipe 15 which means that there is no need to specially provide a bracket for attaching the intake chamber Cm to the frame 1, and the number of components can be reduced to bring about cost reduction. Because the intake chamber Cm above the intake pipe 15 is positioned by detachably engaging with an engagement portion 38, there is no longer any need for positioning components such as screws, etc., and rcmovaf is simple. A first modification to the first embodiment of the present invention will now be described with reference to Fig. 7. Fig 7 shows the modification, and is a plan view of part of a power unit having an intake chamber Cm. Parts that are the same as in the embodiment have the same reference numerals attached thereto. This first modification is different from the embodiment in tb^ The first modification also has the same operational effect as the embodiment.A second modification to the first embodiment of the present invention will now be described with reference to Fig. 8. Fig 8 shows the modification, and is a i plan view of part of a power unit having an intake chamber Cm. Parts that are the same as in the embodiment have the same reference numerals attached thereto. This second modification is different from the embodiment in the shape and arrangement of the intake chamber Cm. In plan view, the intake chamber Cm is formed in a rearwardly open U-shape in front of the air cleaner Ac and on one side of the carburetor Ca. The rear half section 35 is formed symmetrically in the lateral direction, and extend to both left and right sides of the carburetor Ca. Although not shown in the drawing, the upper surface of the intake chamber Cm is at substantially the same level as the air cleaner Ac, the same as in the embodiment. The second modification also has the same operational effect as the embodiment. Description has been given of an embodiment of the present invention, but the present invention is not limited to this embodiment, and various modifications are possible thereto within the scope of the invention. For example, the embodiment of the nresent invention has been described for the case of a 2 cycle engine, but can also be applied to a 4-cycle engine. Further, the intake chamber can also be attached to sections other than the transmission case of the power unit. In the embodiment, the intake chamber Cm is made of synthetic resin, but can also be made of another material. [Effects of the Invention] According to the invention disclosed in claim 1, there is provided an intake assembly for an engine of a motorcycle or three wheeled vehicle, having an intake chamber. A carburetor is disposed in front of an air cleaner supported in a power unit, and the intake chamber is disposed to the side of this carburetor. For this reason, the intake chamber can be integrally provided with the power unit using a dead space in front of an air cleaner, while guaranteeing the necessary capacity. Even if the power unit swings to its full extent, it is possible to avoid interference with a vehicle frame or components for attaching the vehicle frame, and there is no restriction on the shape of the vehicle frame or the layout of attachment components. Also to achieve the above object, according to the invention disclosed in claim 2, there is provided an intake assembly for an engine of a motorcycle or three wheeled vehicle as disclosed in claim 1, wherein an upper surface of the intake chamber is at substantially the same level as an upper surface of the air cleaner, which means that the intake chamber can be arranged making much more effective use of a dead space in front of the air cleaner without projecting upwards from the air cleaner. To achieve the above object, further, according to the invention disclosed in claim 3, there is provided an intake assembly for an engine of a motorcycle or three wheeled vehicle as disclosed in claim 1, wherein the intake chamber is attached to an intake pipe. This means that the number of components can be reduced, contributing to cost reduction, and it is possible to suppress the deterioration of an intake entrance pipe without subjecting the intake entrance pipe to external force such as bending. Further in achieving this object, according to the invention disclosed in claim 4, there iprovided an intake assembly for an engine of a motorcycle or three wheeled vehicle as disclosed in claim 1, wherein a free end of the intake chamber is engaged with the air cleaner, so that attachment and removal of the intake chamber to and from the power unit is simple, and the number of attachment components such as screws for attaching the intake chamber can be reduced, thus contributing to reduced cost. [Description ofthe Numerals] I vehicle frame 15 intake pipe 32 intake entrance pipe Ac air cleaner Ca carburetor Cm intake chamber E engine T transmission Up power unit Wr rear wheel (drive wheel) We claim; 1. An intake assembly for a motorcycle or three or three wheeled vehicle having a power unit (Up), comprising an engine (E), and a driving wheel (Wr) connected to said engine through a transmission (T) vertically swingably mounted on a vehicle frame (1), a carburetor (Ca) and an air cleaner (Ac) sequentially connected to an intake pipe (15) that communicates with an intake port (14) of said engine (E), an intake entrance pipe (32) branching off from the middle of the intake pipe (15), and a intake chamber (Cm) connected to the intake entrance pipe (32), characterized in said carburetor (Ca) is disposed in front of the air cleaner (Ac) supported above said power unit (Up), and said intake chamber (Cm) is disposed at the side of the carburetor (Ca). 2. The intake assembly as claimed in claim 1, wherein an upper surface of said intake chamber (Cm) is at the same level as an upper surface of said cleaner (Ac). 3. The intake assembly as claimed in claim 1, wherein said intake chamber (Cm) is attached to said intake pipe (15). 4. The intake assembly as claimed in claim 1, wherein a free end of said intake chamber (Cm) is engaged with said air cleaner (Ac). 5. An intake assembly for a motorcycle or three wheeled vehicle substantially as hereinbefore described with reference to the accompanying drawings.

Documents:

820-del-1998-abstract.pdf

820-del-1998-claims.pdf

820-del-1998-correspondence-others.pdf

820-del-1998-correspondence-po.pdf

820-del-1998-description (complete).pdf

820-del-1998-drawings.pdf

820-del-1998-form-1.pdf

820-del-1998-form-13.pdf

820-del-1998-form-19.pdf

820-del-1998-form-2.pdf

820-del-1998-form-3.pdf

820-del-1998-form-4.pdf

820-del-1998-form-6.pdf

820-del-1998-gpa.pdf

820-del-1998-petition-137.pdf

820-del-1998-petition-138.pdf

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