Title of Invention	REAR UNIT STRUCTURE FOR MOTORCYCLE
Abstract	A rear unit structure in a motorcycle having a swing arm, comprising at least one of an air cleaner mechanism and a muffler mechanism incorporated in the swing arm of the motorcycle.

Full Text

The present invention relates to a rear unit structure for use in a motorcycle such as a scooter. Description of the Related Art: As shown in FIGS. 9 and 10 of the accompanying drawings, the rear unit of a motorcycle such as a scooter heretofore includes an engine 52 disposed near a pair of laterally spaced swing arms 51a, 51b on which a rear wheel 50 is suspended, a muffler 53 and an air cleaner 54 which are connected as separate parts to the engine 52 and disposed closely to the engine 52, and a rear fender (not shown) as a separate part covering a portion of the rear wheel 50, Since the swing arms 51a, 51b, the muffler 53, the air cleaner 54, and the rear fender are separate com¬ponents, the rear unit is made up of many parts including those ancillary to those separate components. Therefore, it is laborious and time-consuming to assemble the rear unit, and the rear unit takes up a large installation space, resulting in a large size and weight of the motor¬cycle . SUMMARY OF THE INVENTION It is therefore an object of the present in¬vention to provide a rear unit structure for use in a mo¬torcycle, which is made up of a reduced number of parts to reduce the cost of manufacturing and assembling the rear unit structure and reduce the size and weight of the motorcycle. To achieve the above object, there is provided in accordance with a first aspect of the present inven¬tion a rear unit structure in a motorcycle having a swing arm, comprising an air cleaner mechanism incorporated in the swing arm of the motorcycle. With the air cleaner mechanism incorporated in the swing arm to supply cleaned air to the carburetor of an engine, one component is capable of simultaneously performing a rear suspension function and an air cleaning function. Therefore, the number of parts used can be re¬duced, the cost of manufacturing and assembling the rear unit structure can be reduced, and the size and weight of the motorcycle can be reduced. To incorporate the air cleaner mechanism in the swing arm, two steel sheets pressed to shape to pro¬duce bulging portions may be joined to each other, and an air Intake chamber may be defined in the bulging por¬tions. According to a second aspect of the present invention, there is provided a rear unit structure in a motorcycle having a swing arm, comprising a muffler mechanism incorporated in the swing arm of the motorcy¬cle. With the muffler mechanism incorporated in the swing arm to be supplied with an exhaust gas emitted from an engine, one component is capable of simultaneously performing a rear suspension function and a sound muf¬fling function. Therefore, the number of parts used can be reduced, the cost of manufacturing and assembling the rear unit structure can be reduced, and the size and weight of the motorcycle can be reduced. To incorporate the muffler mechanism in the swing arm, two steel sheets pressed to shape to produce bulging web portions may be joined to each other to pro¬vide a gas passage, and expansion chambers may be defined in the gas passage. According to a third aspect of the present in¬vention, there is provided a rear unit structure in a mo¬torcycle having a swing arm, comprising an air cleaner mechanism and a muffler mechanism which are incorporated in the swing arm of the motorcycle. Specifically, the air cleaner mechanism is in¬corporated in a left swing arm, and the muffler roeohanism is incorporated in a right swing arm. With this arrange¬ment, the number of parts used can be reduced, the cost of manufacturing and assembling the rear unit structure can be reduced, and the size and weight of the motorcycle can be reduced. According to a fourth aspect of the present invention, there is provided a rear unit structure in a motorcycle having a rear fender, comprising an air cleaner mechanism incorporated in the rear fender of the motorcycle. With the air cleaner mechanism incorporated in the rear fender, the number of parts used can be reduced, the cost of manufacturing and assembling the rear unit structure can be reduced, and the size and weight of the motorcycle can be reduced. To incorporate the air cleaner mechanism in the rear fender, two steel sheets or two fiber-reinforced resin sheets pressed to shape to produce bulging portions may be Joined to each other, and an air instance chamber may be defined in the bulging portions. According to a fifth aspect of the present in¬vention, there is provided a rear unit structure in a mo¬torcycle having a rear fender, comprising a muffler mechanism incorporated in the rear fender of the motorcy¬cle. With the muffler mechanism incorporated in the rear fender, the number of parts used can be reduced, the cost of manufacturing and assembling the rear unit struck- 5" ture can be reduced, and the size and weight of the mo¬torcycle can be reduced. To incorporate the muffler mechanism in the rear fender, two steel sheets pressed to shape to produce bulging web portions may be joined to each other to pro¬vide a gas passage, and expansion chambers may be defined in the gas passage. According to a sixth aspect of the present in¬vention, there is provided a rear unit structure in a mo¬torcycle having a swing arm, comprising an air cleaner mechanism and a muffler mechanism which are incorporated in the swing arm of the motorcycle. Specifically, the rear fender performs a swing arm function, the air cleaner mechanism is incorporated in a left rear fender member, and the muffler mechanism is incorporated in a right rear fender member. With this arrangement, the number of parts used can be reduced, the cost of manufacturing and assembling the rear unit struc¬ture can be reduced, and the size and weight of the mo¬torcycle can be reduced. If two swing arms or two rear fender members are employed, then one of the swing arms or two rear fender members may be constructed of a fiber-reinforced resin sheet, and the other swing arm or rear fender mem¬ber may be constructed of a steel sheet. With these swing arms or rear fender members being constructed of -X- different materials, the air cleaner mechanism which is not heated to a high temperature is mounted in the swing arm or rear fender member which is constructed of a fi¬ber-reinforced resin sheet, and the muffler mechanism which is heated to a high temperature is mounted in the swing arm or rear fender member which is constructed of a steel sheet. The above and other objects, features, and ad¬vantages of the present Invention will become apparent from the following description when taJcen in conjunction with the accompanying drawings which illustrate preferred embodiments of the present invention by way of example. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational view of a motor¬cycle having a rear unit structure according to an em¬bodiment of the present invention, the rear unit struc¬ture including an air cleaner mechanism and a muffler mechanism that are incorporated in respective swing arms; FIG. 2 is a perspective view of the swing arm incorporating the air cleaner mechanism therein; FIG. 3 is a cross-sectional view taken along line III - III of FIG. 2; FIG. 4 is a perspective view of the swing arm incorporating the muffler mechanism therein; FIG. 5 is a cross-sectional view taJcen along line V - V of FIG. 4; V- 7 FIG. 6 is a cross-sectional view taken along line VI - VI of FIG. 5; FIG. 7 is a side elevatlonal view of a motor¬cycle having a rear unit structure according to another embodiment of the present invention, the rear unit struc¬ture including an air cleaner mechanism and a muffler mechanism that are incorporated in a rear fender; FIG, 8 is a cross-sectional view taken along line VIII - VIII of PIG. 7; FIG. 9 is a fragmentary perspective view of a conventional rear unit which Includes a muffler; and FIG. 10 is a fragmentary perspective view of the conventional rear unit which includes an air cleaner. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1 through 6 show a rear unit structure according to an embodiment of the present invention, the rear unit structure including an air cleaner mechanism and a muffler mechanism that are incorporated in respec¬tive swing arms. As shown in FIG. 1. a motorcycle 1 such as a scooter-type motorcycle has a pair of laterally spaced swing arms 3a, 3b (see also FIGS. 2 and 4) between which a rear wheel 2 is swingably supported. The left swing arm 3a incorporates an air cleaner mechanism therein, and the right swing arm 3b incorporates a muffler mechanism therein. Therefore, each of the swing arms 3a, 3b per¬forms a plurality of functions. As shown in PIGS. 2 and 3. the swing arm 3a with the air cleaner mechanism incorporated therein com¬prises two pressed parts 5, 6 of sheet steel having bulg¬ing central regions and peripheral edges welded to each other. The bulging central regions of the pressed parts 5, 6 define an air inlet chamber M therebetween. The bulging central region of the pressed part 6 which is an outer component has a window 6h to which an air cleaner cover 7 with air inlet holes is detachably coupled. A filter 8 is housed in the air inlet chamber M which is held in communication with a connecting tube 9 mounted on the pressed part 5 which is an inner compo¬nent. Air introduced via the air inlet holes in the air cleaner cover 7 is filtered by the filter 8 in the air inlet chamber M, and then supplied via the connecting tube 9 to an engine carburetor (not shown). The swing arm 3a has two engine joints e on its front end which are coupled to an engine (not shown) so as to provide a swingabl© structure. The swing arm 3a has a rear end constructed so as to be able to pull a chain trained around pulleys connected to the engine and the rear wheel 2. As shown in FIGS. 6 through 8, the swing arm 3b with the muffler mechanism incorporated therein com- X 1 prises two pressed parts 11, 12 of sheet steel having un¬dulating bulging central web regions having sides welded to each other. The bulging central web regions of the pressed parts H, 12 define an undulating gas passage which includes several expansion chambers for reducing noise, as shown in FIG. 6. The swing arm 3b has two engine joints e on its front end which are coupled to the engine (not shown) so as to provide a swingable structure. The swing arm 3b has a rear end constructed so as to be able to pull the chain trained around the pulleys connected to the engine and the rear wheel 2. The swing arms 3a, 3b provides an air cleaner function and a muffler function as well as a suspension function for the rear wheel 2. The swing arras 3a. 3b are effective to reduce the number of parts of the rear unit structure, the cost of manufacturing and assembling the rear unit structure, and the size and weight of the mo¬torcycle . A motorcycle having a rear unit structure ac¬cording to another embodiment of the present invention in which an air cleaner mechanism and a muffler mechanism are incorporated in a rear fender will be described below with reference to FIGS. 7 and 8. As shown in FIGS. 7 and 8, a scooter-type mo¬torcycle 1 has an engine (not shown), a rear fender 13, X- and a rear wheel 2 which are coupled togetner muw a ^^.^^ whose front portion is connected to a motorcycle body by a rubber cushioning member, thus providing a rear cushion structure. The rear fender 13 comprises a pair of fender members 13a, 13b which support a horizontal axle 4 of the rear wheel 2. as shown in FIG. 8. The left rear fender member 13a incorporates an air cleaner mechanism therein, and the right rear fender member 13b incorporates a muffler mechanism therein. The left rear fender member 13a is made of fi¬ber-reinforced sheet resin, and the right rear fender member 13b is made of sheet steel. The air cleaner mechanism in the left rear fender member 13a comprises a laminated sheet of a resin and long glass fibers which is preheated to a temperature higher than the melting point of the resin and pressed to shape by a die. The air cleaner mechanism has a bulging portion projecting outwardly and a recess opening in¬wardly. An inner cover 14 comprising a laminated sheet of a resin and long glass fibers is joined to the rear side of the bulging portion by high-frequency welding or the like, defining an air inlet chamber M in a central region thereof. The air inlet chamber M is of substan¬tially the same structure as the air inlet chamber M /[ shown m FIG. 3. The left rear fender member 13a has a window h defined in the bulging portion thereof, and a filter (not shown) is housed in the air inlet chamber M. The muffler mechanism incorporated in the right rear fender member 13b comprises a rear cover 15 of sheet steel projecting laterally into an inner space in a wheel 2a to define a gas passage and an expansion cham¬ber. The rear cover 15 has peripheral edges joined by staking or the like to the rear side of the right rear fender member 13b of sheet steel that has been pressed to shape. The joined peripheral edges of the rear cover 15 are sealed by a sealer or the like. The rear fender 13 not only functions as a mud guard and a protective cover for the rear wheel 2, but also perfoiTOs an air cleaner function and a muffler func¬tion. The rear fender 13 is effective to reduce the num¬ber of parts of the rear unit structure, the cost of manufacturing and assembling the rear unit structure, and the size and weight of the motorcycle. An air cleaner mechanism and/or a muffler mechanism may be incorporated in on© of the swing arms 3a, 3b or the rear fender members 13a, 13b. The swing arms 3a, 3b and the rear fender mem¬bers 13a, 13b may be made of any arbitrary material. According to the present invention, as de¬scribed above, since the swing arms or the rear fender --to,. incorporates an air cleaner mechanism or a muffler mecha¬nism therein, one component is capable of performing a plurality of functions, so that the number of parts of the rear unit structure can be reduced, the cost of manu¬facturing and assembling the rear unit structure can be reduced, and the size and weight of the motorcycle can also be reduced. Although certain preferred embodiments of the present invention have been shown and described in de¬tail, it should be understood that various changes and modifications may be made therein without departing from the scope of the appended claims. WE CLAIM: 1. A rear unit structure in a motorcycle having a swing arm, comprising at least one of an air cleaner mechanism and a muffler mechanism incorporated in the swing arm of the motorcycle. 2. The rear unit structure according claim 1 wherein the motor cycle has an engine integrally mounted on said swing arm. 3. The rear unit structure according to claim 1, wherein said swing arm comprises a pair of shaped parts joined to each other, at least one of said shaped parts having a bulging portion, said air cleaner mechanism or said muffler mechanism being disposed in said bulging portion. 4. The rear unit structure according to claim 1, wherein said swing arm comprises a pair of swing arms laterally spaced from each other, one of said swing arms being made of fiber-reinforced sheet resin, and the other swing arm being made of sheet steel, said air cleaner mechanism being disposed in said one of the swing arms, said muffler mechanism being disposed in said other swing arm. 5. The rear unit structure according to claim 4, wherein said one of the swing arms comprises a pair of joined shaped parts made of a sheet of a resin which is preheated to a temperature higher than the melting point of the resin and pressed to shape by a die. 6. A rear unit structure in a motorcycle having a rear fender, comprising at least one of an air cleaner mechanism and a muffler mechanism incorporated in the rear fender of the motorcycle. 14 7. The rear unit structure according to claim 6, wherein said rear fender functions as a swing arm on which a rear wheel is suspended. 8. The rear unit structure according to claim 6, wherein the motor cycle has an engine integrally mounted on said rear fender. 9. The rear unit structure according to claim 6, wherein said rear fender comprises a pair of rear fender members joined to each other, at least one of said rear fender members having a bulging portion, said air cleaner mechanism or said muffler mechanism being disposed in said bulging portion. 10. The rear unit structure according to claim 6, wherein said rear fender com- pries a pair of rear fender members joined to each other, one of said rear fender members being made of fiber-reinforced sheet resin, and the other rear fender member being made of sheet steel, said air cleaner mechanism being disposed in said one of the rear fender members, said muffler mechanism being disposed in said other rear fender member. 11. The rear unit structure according to claim 10, wherein said one of the rear fender members comprises a shaped part made of a sheet of a resin which is pre- heated to a temperature higher than the melting point of the resin and pressed to shape by a die.

Documents:

0466-mas-2000 abstract-duplicate.pdf

0466-mas-2000 abstract.pdf

0466-mas-2000 claims-duplicate.pdf

0466-mas-2000 claims.pdf

0466-mas-2000 correspondence-others.pdf

0466-mas-2000 correspondence-po.pdf

0466-mas-2000 description (complete)-duplicate.pdf

0466-mas-2000 description (complete).pdf

0466-mas-2000 drawings-duplicate.pdf

0466-mas-2000 drawings.pdf

0466-mas-2000 form-1.pdf

0466-mas-2000 form-19.pdf

0466-mas-2000 form-26.pdf

0466-mas-2000 form-3.pdf

0466-mas-2000 form-5.pdf

0466-mas-2000 petition.pdf