Title of Invention

"SCOOTER TYPE VEHICLE COMPRISING A POWER UNIT AND A REAR WHEEL"

Abstract

A scooter type vehicle includes a light alloy made front frame and a synthetic resin made rear frame. A front end of a power unit including a rear wheel at a rear end thereof is vertically movably supported on a rear portion of the front frame, and the front end of the power unit is connected to a lower end of a rear cushion via a link mechanism. Accordingly, when the power unit is vertically moved, the rear cushion is compressed by the link mechanism, to achieve a damping effect. The rear portion of the front frame includes a recessed portion having an inverse U-shaped cross-section with the lower side opened, and the rear cushion is contained in an internal space of the recessed portion. Part of the front frame, which is exposed from openings of a leg shield and a step floor, is utilized as an appearance member, so that it becomes possible to make smaller sizes of other appearance members such as the leg shield and the step floor.

Full Text

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scooter type vehicle including a front frame and a rear frame connected to each other. 2. Description of the Related Art Scooter type vehicles of this type have been known, for example, from Japanese Patent Laid-open No. Hei 7-156851. The scooter type vehicle includes a frame structure having a synthetic resin made rear frame connected to a rear portion of a steel pipe welding type front frame, wherein an article containing compartment is formed integrally with the rear frame. The above-described frame structure including the steel pipe welding type front frame, however, has problems that a large number of reinforcing members such as gussets must be welded to the front frame to ensure a sufficient strength, resulting in the increased weight and cost, and that design of the frame is restricted. Moreover, in the above-described frame structure, the steel pipe welding type front frame must be perfectly covered with a leg shield and a step floor because the front frame, if it is externally exposed, degrades the appearance quality of the vehicle. SUMMARY OF THE INVENTION In view of the foregoing, the present invention has been made, and an object of the present invention is to provide a scooter type vehicle including a frame structure being light, strong, and inexpensive, and also having a high degree of freedom in design. i To achieve the above object, according to a first aspect of the present invention, there is provided a scooter type vehicle including: a power unit including a rear wheel at a rear portion thereof; a front frame, made from a light alloy or a synthetic resin, for vertically movably supporting at a rear portion thereof a front portion of the power unit; and a rear cushion for damping vertical movement of the power unit, which is disposed in front of the power unit; wherein the front frame has a recessed portion having an inverse U-shape with the lower side opened, and at least an upper portion of the rear cushion is contained in the recessed portion. With this configuration, since the front frame is made from a light alloy or a synthetic resin, it becomes possible to eliminate the need of provision of reinforcing members such as gussets resulting in the reduced weight and cost, and to significantly increase the degree of freedom in design of the front frame. Moreover, since at least an upper portion of the rear cushion is contained in an inverse U-shaped recessed portion of the front frame, it becomes possible to cover the rear cushion and improve the appearance quality of the vehicle, and to sufficiently ensure the stroke of the rear cushion. According to a second aspect of the present invention, there is provided a scooter type vehicle including: a front frame, made from a light alloy or a synthetic resin, extending rearward from a head pipe; and a leg shield provided on a front portion of the front frame; wherein the leg shield has an opening portion at a lower rear surface thereof, and at least part of the front frame is exposed from the opening portion. With this configuration, since the front frame is made from a light alloy or a synthetic resin, it becomes possible to eliminate the need of provision of reinforcing members such as gussets resulting in the reduced weight and cost, and to significantly increase the degree of freedom in design of the front frame. Moreover, since at least part of the front frame made from a light alloy or a synthetic resin is utilized as an appearance member, it becomes possible to make smaller sizes of other appearance members such as the leg shield and the step floor and hence to reduce the cost. BRIEF DESCRIPTION OF THE DRAWINGS These and other objects, features and advantages of the present invention will become more apparent from the following description of preferred embodiments, taken in connection with the accompanying drawings in which: Fig. 1 is a side view showing the entire configuration of a scooter type vehicle of the present invention; Fig. 2 is an enlarged view of essential portions of the vehicle shown in Fig. 1; Fig. 3 is an enlarged sectional view taken on line 3-3 of Fig. 2; Fig. 4 is an enlarged view of a progressive link; Fig. 5 is sectional view taken on line 5-5 of Fig. 4; Fig. 6 is a view corresponding to Fig. 4, illustrating the function of the present invention; and Fig. 7 is a side view showing the entire configuration of a scooter type vehicle according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in Figs. 1 to 3, a scooter type vehicle V includes a front frame FF integrally formed by casting a light alloy such as an aluminum alloy. A head pipe 1 is formed integrally with a front end of the front frame FF, and a front fork 3 is right and left rotatably supported on the head pipe 1. The front fork 3 has a steering handlebar 2 disposed on an upper end thereof and a front wheel Wf rotatably supported on a lower end thereof. A main body portion 4 of the front frame FF extending rearward, downward from the head pipe 1 has a transverse cross-section formed in an inverse u-shape with the lower side opened (see Fig. 3), and contains a plurality of reinforcing ribs 5,—, 5 formed integrally on the inner surface thereof. A rear end of the front frame FF reaches a lower front end of a seat 6, at which right and left side walls 7, 7 and a substantially horizontal upper wall 8 connecting upper ends of the side walls 7, 7 to each other are integrally formed. A space formed between the right and left side walls 7, 7 is blocked by the rearmost reinforcing rib 5 and the upper wall 8 on front and rear upper sides thereof respectively, and is opened on front and rear lower sides thereof. A synthetic resin made leg shield 9 covering a front side of a leg portion of the rider sitting on the seat 6 is mounted to cover front and rear surfaces of the head pipe 1. The leg shield 9 has a horizontally elongated opening 9i at a lower rear surface thereof, and as shown in Fig. 3, a peripheral edge portion of the opening 9: is connected to flanges 10, 10 projecting right and left from a lower surface opening of the main body portion 4 of the front frame FF by means of bolts 11, ..., 11. A rear portion of the leg shield 9 is connected to a synthetic resin made step floor 12 for supporting the feet of the rider sitting on the seat 6. An upper surface of the step floor 12 has an opening 12i connected to the opening BI of the leg shield 9 (see Fig. 1), and right and left side edges of the opening 12j are fixed on upper surfaces of flanges 13, 13 projecting from outer surfaces of the right and left side walls 7, 7 of the front frame FF (see Fig. 4). Accordingly, upper half portions of the right and left side walls 7, 7 of the front frame FF are exposed at a widthwise central portion of the step floor 12 for supporting the rider's feet. In this way, by making use of part of the front frame FF as a visible appearance member, it becomes possible to make smaller the sizes of the leg shield 9 and the step floor 12 and hence to reduce the cost. The front frame FF formed by casting a light alloy is higher in degree of freedom in design than a steel pipe welding type frame; accordingly the frame, if it is externally exposed, does not degrade the appearance quality. A fuel tank 14 contained in an internal space of the step floor 12 is fixed in such a manner that a front upper surface thereof is fastened by means of bolts 16, 16 to a pair of right and left mounting brackets 15, 15 projecting from the lower end of the main body portion 4 of the front frame FF and a rear upper surface thereof is fastened by means of bolts 17, 17 to the right and left side walls 7, 7. An oil filler cap 19 for opening/closing a leading end of an oil filler pipe 18 extending forward, upward from the fuel tank 14 faces a lid 20 provided on the leg shield 9. A lower surface of a front end of a synthetic resin made rear frame RF is connected to an upper wall 8 of the front frame FF by means of a plurality of bolts 21, —, 21. A helmet box 22 with an upper surface thereof opened is formed in a front half of the rear frame RF, and a helmet H is to be contained in the helmet box 22. A small article containing compartment 24 is formed behind the helmet box 22 while putting an oil tank 23 therebetween. A lower side opening of the oil tank 23 and the small article containing compartment 24 is blocked by a bottom plate 25. A peripheral portion of the rear frame RF is covered with a synthetic resin made rear body 26, and an upper surface of the rear body 26 is opened/closed by the seat 6. When the seat 6 is swung forward around a hinge 27 provided at a front end of the seat 6, the helmet box 22 and the small article containing compartment 24 can be opened. A power unit P mounting a single cylinder engine E at the front portion thereof includes a casing 28 serving as a crank case for the engine E and a transmission case for a belt type continuously variable transmission, and a rear wheel Wr is rotatably supported on a rear end of the casing 28. As seen from Figs. 4 and 5, a pair of right and left mounting arms 31, 31 are fixed to a front end of the casing 28 of the power unit P by means of an upper fixing bolt 29 and a lower fixing bolt 30. The mounting arms 31, 31, each being formed of a plate-like member, are integrally connected to each other by means of boss portions 32, 33 through which the two bolts 29, 30 pass respectively. A rear end of an inverse firm-set mouth like link 36 is pivotably supported on an intermediate portion of a bolt 35 passing through a position in front of the lower fixing bolt 30. A front end of the link 36 is pivotably supported on a lower end of a rear cushion 37 disposed between the right and left mounting arms 31, 31 by means of a bolt 38, and an upper end of the rear cushion 37 is pivotably supported on a bracket 39 projecting from a lower surface of the upper wall 8 of the front frame FF by means of a bolt 40. An intermediate bent portion of the link 36 is pivotably supported by means of a bolt 42 on a rear end of a tension rod 41 formed substantially in a U-shape and surrounding the rear cushion 37. A bolt 43 passing through a front end of the tension rod 41 is pivotably supported on lower ends of the right and left side walls 7, 7 of the front frame FF. In this way, since the tension rod 41 applied with a large load is supported on the right and left side walls 7, 7 formed integrally with the front frame FF, it becomes possible to provide a sufficient supporting strength. An intermediate portion of a stopper arm 44 L-shaped in a side view is pivotably supported on the right and left walls 7, 7 of the front frame FF by means of a bolt 45. One end portion of the stopper arm 44 is pivotably supported on the front ends of the right and left mounting arms 31, 31 by means of a bolt 46, and the other end of the stopper arm 44 faces an elastic stopper 47 provided between the right and left side walls 7, 7 in such a manner as to be freely brought in contact with the elastic stopper 47. Both the side walls 7, 7 are formed with slots 7j, 71, through which the bolt 46 passes, the bolt 46 connecting the stopper arm 44 positioned inside the right and left side walls 1, 7 to the mounting arms 31, 31 positioned outside the right and left side walls 7, 7. The link 36 and the tension rod 41 constitutes a progressive link mechanism 48. Next, the function of the embodiment of the present invention having the above-described configuration will be described. When an upward load is applied to the rear wheel Wr and the power unit P is swung upward, the link 36 is moved upward and the tension rod 41 is swung upward around the bolt 43 as shown in Figs. 4 and 6, as a result of which the rear cushion 37 is compressed and the upward load applied to the rear wheel Wr is damped. As the upward swing amount of the power unit P is increased, the other end of the stopper arm 44 is swung backward and is brought in contact with the stopper 47, to thereby restrict the upper swing end of the power unit P. Thus, by the action of the progressive link mechanism 48 composed of the link 36 and the tension rod 41, the compressed amount of the rear cushion 37 can be made acceleratedly larger with the increasing upward swing amount of the power unit P, to achieve a desirable damping characteristic in term of riding quality. Since the rear cushion 37 is disposed in the space formed between the right and left mounting arms 31, 31 and also positioned rearward from the front end of the progressive link mechanism 48, the floor space on the upper surface of the step floor 12 is not restricted by the presence of the rear cushion 37, to thereby improve comfortability. Moreover, since the rear cushion 37 is contained in the front frame FF having an inverse U-shaped cross-section, it becomes possible to cover the rear cushion 37 in a state not being visible from the outside and hence to improve the appearance quality, and to ensure a vertical space allowing a sufficient stroke of the rear cushion. The front frame FF made from an aluminum alloy casting is lighter, stronger and cheaper and also it is higher in degree of freedom in design than a steel pipe welding type frame. In addition, it is advantageous in terms of strength that the heavier power unit P and the rear cushion 37 applied with a large load are supported on the strong front frame FF. Since the rear frame RF not requiring a high strength so much as compared with the front frame FF is made from a synthetic resin, it becomes possible to increase a weight reducing effect, and to reduce the number of parts by directly forming the helmet box 22 and the small article containing compartment 24 in the rear frame RF. Next, a second embodiment of the present invention will be described. The second embodiment is different from the first embodiment in terms of usage of the internal space of the rear frame RF. Specifically, the small article containing compartment 24 is formed behind the oil tank 23 in the rear frame RF in the first embodiment; however, the fuel tank 14 is contained at the position of the small article containing compartment 24 in the second embodiment. As a result, the lower space of the step floor 12 has not the fuel tank 14, and thereby the space can be used for another application or the height of the step floor 12 can be lowered to further improve the comfortability. While the preferred embodiments of the present invention have been described using specific terms, such description is for illustrative purposes only, and it is to be understood that changes and variations in design may be made without departing from the scope or spirit of the following claims. For example, the front frame FF made from a light alloy in the embodiments may be made from a synthetic resin, and the rear frame RF made from a synthetic resin in the embodiment may be made from a light alloy or a welded steel pipe. Although the cylinder of the engine E is disposed rearward, upward in the embodiments, it may be disposed forward in the horizontal direction. In this case, the upper end of the rear cushion 37 may be mounted at a position near the front portion of the front frame FF to avoid interference with the cylinder. The progressive link mechanism 48 may be replaced with a usual link mechanism. In addition, although the mounting arms 31, 31 are formed separately from the casing 28 of the power unit P in the embodiments, it may be formed integrally with the casing 28. 1. A scooter type vehicle comprising: a power unit including a rear wheel at a rear portion thereof; a front frame, made from a light alloy or a synthetic resin, for vertically movably supporting at a rear portion thereof a front portion of said power unit; and a rear cushion for damping vertical movement of said power unit, which is disposed in front of said power unit; wherein said front frame has a recessed portion having an inverse U-shape with the lower side opened, and at least an upper portion of said rear cushion is contained in said recessed portion. 2. A scooter type vehicle according to claim 1, further comprising a link mechanism for transmitting vertical movement of said power unit to a lower end of said rear cushion, said link mechanism being supported on a link supporting portion formed integrally with said front frame. 3. A scooter type vehicle according to claim 2, further comprising a pair of right and left mounting arms projectingly provided on the front portion of said power unit, wherein said pair of right and left mounting arms are supported on said front frame via said link mechanism and said rear cushion is disposed between said pair of right and left mounting arms. 4. A scooter type vehicle according to claim 1, further comprising a rear frame removably mounted on the rear portion of said front frame. 5. A scooter type vehicle according to claim 4, wherein said rear frame is provided with an article containing compartment. 6. A scooter type vehicle according to claim 5, wherein said rear frame is made from a synthetic resin and said article containing compartment is formed integrally with said rear frame. 7. A scooter type vehicle according to claim 1, further comprising a fuel tank provided under said front frame in front of said rear cushion. 8. A scooter type vehicle according to claim 1, further comprising a fuel tank provided in a rear portion of said rear frame. 9. A scooter type vehicle comprising: a front frame, made from a light alloy or a synthetic resin, extending rearward from a head pipe; and a leg shield provided on a front portion of said front frame; wherein said leg shield has an opening portion at a lower rear surface thereof, and at least part of said front frame is exposed from said opening portion. 10. A scooter type vehicle according to claim 9, further comprising right and left step floors provided on a rear portion of said front frame, wherein said front frame is swelled upward from a space between said right and left step floors. 11. A scooter type vehicle substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

Documents:

216-del-1997-abstract.pdf

216-del-1997-claims.pdf

216-del-1997-correspondence-others.pdf

216-del-1997-correspondence-po.pdf

216-del-1997-description (complete).pdf

216-del-1997-drawings.pdf

216-del-1997-form-1.pdf

216-del-1997-form-13.pdf

216-del-1997-form-19.pdf

216-del-1997-form-2.pdf

216-del-1997-form-4.pdf

216-del-1997-form-6.pdf

216-del-1997-gpa.pdf