Title of Invention

"A MOTOR SCOOTER FRAME STRUCTURE"

Abstract

A lightweight, rigid main frame having a high strength for a motor scooter is provided. [CONSTITUTION] In a motor scooter frame structure having a main frame, for a motor scooter having a low floor board (29) disposed on a longitudinally middle section of the main frame, a power unit disposed under a rear section of the main frame, obliquely upwardly extending behind the floor board, and a shock absorber (26) having one end connected to the rear section of the main frame and the other end connected to the power unit, a portion of the main frame between a position in the middle section of the main frame behind the floor board and a position in a rear end portion (7e) of a rear section of the main frame at which the one end of the shock absorber is connected to the rear section of the main frame is formed from a hollow member having a high rigidity, and a portion of the rear section of the main frame extending behind the position in the rear section of the main frame at which the one end of the shock absorber is connected to the rear section of the main frame is a subframe formed by molding a lightweight

Full Text

The present invention relates to a frame structure for a motor scooter having a low floor board in a longitudinally middle portion thereof, having a rear section obliquely upwardly extending behind the floor board. [0002] [Related Art] As mentioned in JP-A No. 58-67579 (Fig. 27) and JP-U No. 63-51886, in a conventional motor scooter provided with a low floor board 01, a rear frame 03, i.e., a rear section of a main frame 02, is raised from a position of the main frame 02 behind the floor board 01 and is bent so that a horizontal rear section 04 of the rear frame 03 extends rearward, and functional parts 05 including electrical parts are attached to the horizontal rear section 04 of the rear frame 03. [0003] [Problem to be Solved by the Invention] Only lightweight functional parts 05 and a rear cover 06 are attached to a rear end portion 04a of the horizontal rear section 04 of the rear frame 03 of the motor scooter shown in Fig. 27, extending rearward from a position at which a shock absorber support rod 07 is attached to the rear frame 03, and any heavy parts are not loaded thereon. Therefore, the rear end portion 04a need not be as strong as a front portion 04b extending forward from the position at which a shock absorber support rod 07 is attached to the rear frame 03. However, since the rear end portion 04a of the horizontal rear section 04 has the same cross section as that of the front portion 04b, the rear frame 03 is relatively heavy. [0004] Since it is difficult to attach the functional parts 05 and the rear cover 06 directly to the tubular rear frame 03, the rear frame 03 needs to be provided with stays 07 and 08, which increases the number of parts and the number of machining steps, and entails unavoidable increase in the cost. [0005] [Means for Solving the Problem and Effect] The present invention has been made to overcome such disadvantages and to provide an improved motor scooter frame structure having a main frame, for a motor scooter having a low floor board disposed on a longitudinally middle section of the main frame, a power unit disposed under a rear section of the main frame, obliquely upwardly extending behind the floor board, and a shock absorber having one end connected to the rear section of the main frame and the other end connected to the power unit, wherein a heavy portion of the main frame between a position on the middle section of the main frame behind the floor board and a position on the rear section of the main frame at which the one end of the shock absorber is connected to the rear section of the main frame is formed from a hollow member having a high rigidity, and a portion of the rear section of the main frame extending behind the position on the rear section of the main frame at which the one end of the shock absorber is connected to the rear section of the main frame is a subframe formed by molding a lightweight material, such as aluminum, an aluminum alloy or a synthetic resin. [0006] Since the heavy portion of the main frame between a position on the middle section of the main frame behind the floor board and the position on the rear section of the main frame at which the one end of the shock absorber is connected to the rear section of the main frame is formed from a hollow member having a high rigidity, a high reaction force of a rear wheel can surely be sustained by the main frame. [0007] Since the portion of the rear section of the main frame extending behind the position on the rear section of the main frame at which the one end of the shock absorber is connected to the rear section of the main frame is a subframe formed by molding a lightweight material, such as aluminum, an aluminum alloy or a synthetic resin, and functional parts including electrical equipment are mounted on the subframe, any special parts for attaching the functional parts are not necessary, the functional parts can easily and firmly be attached to the main frame in places an in positions suitable for the shapes and functions of the functional parts. [0008] Since the heavy portion of the main frame on which a large load is applied through the shock absorber is formed from a hollow member having a high rigidity, and the portion of the main frame on which not very heavy functional parts are mounted is a molded subframe of a lightweight material, the strength and rigidity of the main frame are distributed rationally to construct the body of the motor scooter in a compact, lightweight structure at a low cost. [0009] Since the hollow main frame has a rectangular cross section as stated in claim 3, the hollow main frame has an increased bending rigidity an increased torsional rigidity. [0010] Sine the subframe is provided integrally with the carrier holding stays as stated in claim 4, a carrier can easily and firmly attached to the subframe. [0011] Since the front end portion of the subframe is fixedly inserted in a rear open end portion of the hollow main frame as stated in claim 5, the subframe can easily be attached to and detached from the hollow main frame, and can firmly be joined to the hollow main frame. [0012] Since the subframe is provided with a seat locking member as stated in claim 6, a seat hinged on the main frame so as to be turned in a vertical plane can be locked. [0013] Since a front end portion of the subframe is fastened together with a fuel tank attaching parts to the main frame as stated in.claim 7, a fuel tank can firmly be fastened to a joint of the maimframe and the subframe when joining together the subframe and the main frame. [BRIEF DESCRIPTION OF THE DRAWINGS] [Fig. 1] Fig. 1 is a side view of a motor scooter provided with a frame structure in a preferred embodiment according to the present invention. [Fig. 2] Fig. 2 is a side view of an assembly of a down frame and a rear frame included in the frame structure of Fig. 1. [Fig. 3] Fig. 3 is a plan view of an essential portion of the assembly shown in Fig. 2. [Fig. 4] Fig. 4 is a plan view of a rear end portion of the rear frame/ a subframe joined to the rear end portion of the rear frame, and a rear fender joined to the rear end portion of the rear frame and the subframe. [Fig. 5] Fig. 5 is an enlarged side view of a portion indicated at V in Fig. 2. [Fig. 6] Fig 6 is a cross-sectional view taken on line VI-VI in Fig. 2. [Fig. 7] Fig 7 is a cross-sectional view taken on line VII-VII in Fig. 2. [Fig. 8] Fig. 8 is a plan view of a subframe. [Fig. 9] Fig. 9 is a fragmentary longitudinal sectional view taken on line IX-IX in Fig. 8. [Fig. 10] Fig. 10 is a cross-sectional view taken on line X-X in Fig. 8. [Fig. 11] Fig. 11 is a cross-sectional view taken on line XI-XI in Fig. 8. [Fig. 12] Pig. 12 is a cross-sectional view taken on line XII-XII in Fig. 8. [Fig. 13] Fig. 13 is a fragmentary longitudinal sectional view of the frame structure shown in Fig. 1. [Fig. 14] Fig. 14 is a side view of a rear fender. [Fig. 15] Fig. 15 is a plan view of portions of the rear frame/ the subframe and the rear fender corresponding to those shown in Fig. 4. [Fig. 16] Fig. 16 is a cross-sectional view taken on line XVI-XVI in Fig. 15. [Fig. 17] Fig. 17 is a front view of the rear fender. [Fig. 18] Fig. 18 is a cross-sectional view taken on line XVIII-XVIII in Fig. 14. [Fig. 19] Fig. 19 is an enlarged longitudinal sectional view of the essential portion shown in Pig. 13. [Pig. 20] Fig. 20 is a side view of a body cover. [Pig. 21] Fig. 21 is a plan view of the body cover shown in Fig. 20. [Fig. 22] Fig. 22 is a front view of the body cover shown in Fig. 20. [Fig. 23] Fig. 23 is an enlarged longitudinal sectional view of the essential portion shown in Fig. 13. [Fig. 24] Fig. 24 is a longitudinal sectional view taken on line XXIV-XXIV in Fig. 19. [Fig. 25] Fig. 25 is a cross-sectional view taken on line XXV-XXV in Fig. 24. [Fig. 26] Fig. 26 is a cross-sectional view taken on line XXVI-XXVI in Fig. 19. [Fig. 27] Fig. 27 is an exploded perspective view of a conventional frame structure. [Preferred Embodiments of the Invention] A motor scooter frame structure in a preferred embodiment according to the present invention shown in Figs. 1 to 10 will be described hereinafter. Referring to Fig. 1, a motor scooter 1 has a main frame 2, a front wheel 3 disposed on the front end of the main frame 2, and a rear wheel 4 disposed on the rear end of the main frame 2. The main frame 2 comprises a head pipe 5, a down frame 6 having the shape of a round pipe, and having a front section extending downward from the head pipe 5 and a rear section extending substantially horizontally rearward under a floor board 29, and a hollow rear frame 7 having a rectangular cross section iiaving a transverse dimension, i.e., a dimension along the width of the body of the motor scooter, greater than a vertical dimension, joined to a rear end portion 6a of the down frame 6 and extending obliquely upward toward the rear. A front section 7a of the rear frame 7 is curved downward so as to extend rearward under a power unit 21. [0015] As shown in Fig. 2, the rear end section 6a of the down frame 6 is gently curved down, and has a flat upper surface capable of being closely joined to the lower surface of the rear frame 7. Side edges of joined portions of the down frame 6 and the rear frame 7 are welded together. [0016] A front gusset 8 is disposed between the upper surface of a horizontal rear section 6b of the down frame 6 extending on the front side of the joint of the down frame 6 and the rear frame 7, and a front surface of a rising section 7b of the rear frame 7 extending above the joint of the down frame 6 and the rear frame 7 as shown in Fig. 2 and is welded to the same surfaces as shown in Fig. 6. The front gusset 8 reinforces and enhances the rigidity of the joint of the down frame 6 and the rear frame 7. [0017] As shown in Fig. 2, a curved section 7c of the rear frame 7 extending upward from the rising section 7b is curved gently rearward. A rear gusset 9 is welded to the rear surface and the both side surfaces of the curved section 7c as shown in Fig. 7. The rear gusset 9 reinforces and enhances the rigidity of the curved section 7c of the rear frame 7. [0018] A main stand bracket 10 having a side view substantially resembling the letter Z is welded to a lower curved section 7d extending rearward from the front section 7a of the rear frame 7. A main stand 11 is pivotally supported for swing motion on the main stand bracket 10 by a pivot shaft 12, and an extension coil spring 13 is extended between a spring peg lOd attached to the main stand bracket 10, and a spring hanger lid formed on the main stand 11. [0019] Referring to Fig. 6, a hanger sleeve 14 is extended through the right and left side walls of the rising section 7b of the rear frame 7 and the right and left side walls of the front gusset 8, and the hanger sleeve 14 is welded to the right and left side walls of the rising section 7b of the rear frame 7. As shown in Fig. 1, a hanger pin 15 is fitted in the hanger sleeve 14, a pair of hanger links 16 are supported at their front ends on the opposite ends of the hanger pin 15, respectively. A front end of a power unit 21 is supported by a support pin 17 on the rear ends of the hanger links 16 so that the power unit is able to swing on the support pin 17 in a vertical plane. [0020] As shown in Figs. 5 and 16, a bracket 18 is welded to the left side surface of a rear end portion 7e of the curved section 7c, and a shock absorber support shaft 19 is welded to the bracket 18. An ignition coil support stay 20 is welded to the right side surface of the rear end portion 7e of the curved section 7c of the rear frame 7. The base end of the shock absorber support shaft 19 is welded to the ignition coil support stay 20. [0021] The power unit 21 comprises an internal-combustion engine 22, a V-belt type CVT (continuous variable transmission) 23 and a reduction gear 24. The rear wheel 4 is fixedly mounted on the output shaft of the reduction gear 24. The upper and the lower end of a rear shock absorber 26 are pivotally connected to the shock absorber support shaft 19 attached to the rear end portion 7e of the rear frame 7 and power unit support shaft 25 for suspending the power unit 21 from che shock absorber 26, respectively. The weight of the rear half of the motor scooter 1 is born through the rear shock absorber 26 and the power unit 21 by the rear wheel 4. [0022] Floor support pipes 27 are extended transversely through vertically middle portions of a horizontal middle section 6c and the horizontal rear section 6b of the down frame 6/ and welded to the rear frame 7. Floor support brackets 28 are welded to the upper surfaces of the opposite ends of the floor support pipes 27, and the floor board 29 is attached to the floor support brackets 28. [0023] Referring again to Fig. I, a steering shaft 30 is rotatably supported in the head pipe 5, a handlebar 31 is attached to the upper end of the steering shaft 30, a front fork 32 having a pair of front suspensions is joined to the lower end of the steering shaft 30, and the front wheel 3 is supported for rotation on the lower end of the front suspensions of the front fork 32. [0024] An air cleaner 33 is disposed above the V-belt type CVT 23. a carburetor 34 is disposed in front of the air cleaner 33, and a muffler 35 is disposed on one side of the rear wheel 4 opposite the side on which the V-belt type CVT 23 is disposed. [0025] As shown in Fig. 4, the rear end portion 7e of the rear frame 7 is cut horizontally and longitudinally of the main frame, i.e., obliquely to the direction of extension of the rear end portion 7e of the rear frame 7 extending obliquely upward, and, as shown in Figs. 4 and 23, a front end section 36a of a cast subframe 36 of aluminum is inserted in the rear end portion 7e of the rear frame 7 through the open rear end of the rear end portion 7e. The front end portion 36a of the subframe 36 is fastened together with a rear tank bracket 38 to the rear end portion 7e of the rear frame 7. [0026] Referring to Figs. 8 to 12, the front end portion 36a of the subframe 36 is provided with a bore 36b and a slit 36c (as shown in Figs. 9 and 13, the bore 36b is formed in a central rib 36d and two side ribs 36d, and the slit 36c is formed in a thin wall 36e). A bolt 40 is inserted through the bore 36b and the slit 36c formed in the front end portion 36a of the subframe 36, holes 7f formed in the side walls of the rear end portion 7e of the rear frame 7, and holes 38b formed in the side walls 38a of the rear tank bracket 38 attached to the rear end portion of the bottom wall of a fuel tank 37r a nut, not shown, is screwed on the threaded portion of the bolt 40, bolts 41 are inserted through holes 7g formed in the lower wall of the rear end portion 7e of the rear frame 7 and vertical holes 36r formed in the front end portion 36a of the subframe 36, as shown in Figs. 3, 11 and 13, and nuts 42 are screwed on the threaded portions of the bolts 41 to fasten the front end portion 36a of the subframe 36 to the rear end portion 7e of the rear frame 7. [0027] As shown in Figs. 1 and 7, a front tank bracket 39 is welded to a front portion of the lower wall of the fuel tank 37. A tank holding sleeve 43 is welded to the upper surface of the curved section 7c of the rear frame 7 so as to extend in the direction of the width of the body, a bolt 44 is inserted through holes 39b formed in the side walls 39a of the front tank bracket 39 and the tank holding sleeve 43, and a nut 45 is screwed on the threaded portion of the bolt 44. Thus, the rear tank bracket 38 is fastened to the rear end portion 7e of the rear frame 7, and the front tank bracket 39 is fastened to the curved section 7c of the rear frame 7 to hold the fuel tank 37 securely on the rear frame 7. [0028] A rear fender attaching arrangement (Fig. 4) for attaching a rear fender 46 made of a synthetic resin to the rear frame 7 and the subframe 36 will be described hereinafter. Figs. 14 to 18 show the rear fender 46. The rear fender 46 is provided with an arm 46b capable of engaging with an upper surface of the shock absorber support shaft 19 from the front of the same in the front left-hand side portion 46a thereof, a downward convex recess 46d formed in the front right-hand side 46c thereof, and an opening 46e formed on the left side of the recess 46d. The rear fender 46 is put to the lower surface of the rear end portion 7e of the rear frame 7 from below the rear frame 7 so that an end portion 20a of the ignition coil support stay 20 is inserted in the opening 46e of the rear fender 46 and the arm 46b is brought into engagement with the shock absorber support shaft 19 as shown in Fig. 16 to hold a front end portion of the rear fender 46 on the rear frame 7. [0029] As shown in Fig. 18, the rear fender 46 is provided in its rear central portion with a raised part 46f provided with a hole 46g formed in its upper wall. As shown in Fig. 19, the raised part 46f of the rear fender 46 is put to the lower surface of a rear depression 36e formed in a rear portion of the subframe 36, a bolt is inserted through a hole 36f formed in the rear depression 36e of the subframe 36 and a hole 46g formed in the upper wall of the raised part 46f of the rear fender 46, and a nut 48 is screwed on a threaded portion of the bolt 47 to fasten the rear portion of the nut 48 to the subframe 36. [0030] A body cover attaching arrangement for attaching a body cover 50 made of a synthetic resin in a shape shown in Figs. 20 to 22 to the main frame will be described hereinafter. A front upper portion of the body cover 50 is cut to form an opening 50a, and a center cover 49 is detachably attached to the body cover 50 so as to cover the opening 50a. [0031] As shown in Fig. 20, a plurality of fastening lugs 50b are formed integrally with the body cover 50 at predetermined intervals so as to project from a front section of the lower edge of the body cover 50. As shown in Figs. 20 and 23, a cylindrical raised part 50d is formed in a central section 50c of the body cover 50, and a battery container 50e having an open upper end is formed behind the cylindrical raised part 50d. As shown in Fig. 1, the fastening lugs 50b of the body cover 50 are inserted in holes, not shown, formed in the upper edge 29b of a rear cover 29a for the floor board 29. As shown in Fig. 23, an upper portion of an oil tank 51 is received in the cylindrical raised part 50d of the body cover 50, and a battery 52 is contained in the battery container 50e of the body cover 50 as shown in Fig. 1. [0032] As shown in Figs. 23 to 25 and 19, the body cover 50 is fastened to the subframe 36. As shown in Fig. 23, a bolt 53 is inserted through a hole 50g formed in the bottom wall 50f of the battery container 50e of the body cover 50 and a hole 36g formed in the subframe 36, and a nut 54 is screwed on a threaded portion of the bolt 53 to fasten the body cover 50 to the subframe 36. [0033] As shown in Figs. 4, 8, 9, 24 and 25, raised parts 36h are formed in right and left portions of the subframe 36 at positions corresponding to positions on the body cover 50 behind the battery container 50e, threaded holes 36j are formed in upper cylindrical portions 36i of the raised parts 36h, respectively/ and a hole 361 is formed in a rear end portion 36k of the subframe 36. As shown in Fig. 21, holes 50h are formed in the body cover 50 on the right and left side of a position behind the battery container 50e, and a hole 50i is formed in the body cover 50 in its rear end portion. [0034] As shown in Figs. 24 and 25, the upper cylindrical portions 36i of the subframe 36 are fitted in the holes 50h of the body cover 50, rubber bushings 55 are put on the upper cylindrical portions 36i, front fitting arms 56a of a carrier 56 are put to the top surfaces of the upper cylindrical portions 36i of the subframe 36, and bolts 57 are screwed through the front fitting arms 56a in the threaded holes 36j of the subframe 36 to fasten the front fitting arms 56a of the carrier 56 to the subframe 36. As show in Figs. 13 and 19, the hole 50h of the body cover 50 is aligned with the hole 361 formed in the rear end portion 36k of the subframe 36, a bolt 59 is inserted through a rear fitting arm 56b of the carrier 56, a cushioning rubber 58, the hole 50h of the body cover 50 and the hole 361 of the rear end portion 36k of the subframe 36, and a nut 60 is screwed on a threaded portion of the bolt 59 to fasten the carrier 56 together with the body cover 50 to the subframe 36. [0035] A seat 61 is hinged to the front end of the fuel tank 37 for turning in a vertical plane. As shown in Fig. 24, a U-shaped shackle 62 is attached to the rear end of the seat 61 so as to project downward. As shown in Figs. 19 and 24, a seat locking mechanism 63 having a catching member 63a that catches the shackle 62 is mounted on the subframe 36. Holes 63c are formed one behind the other in a base 63b, holes 36m are formed one behind the other in a portion of the subframe 36 on the inner side of the left raised part 36h of the subframe 36, bolts 64 are inserted through the holes 36m and 63c from below, and nuts 65 are screwed on threaded portions of the bolts 64 to fasten the seat locking mechanism 63 to the subframe 36. As shown in Fig. 25, circular holes 36n and 50j are formed respectively in the subframe 36 and the body cover 50 to extend a cylinder 63d of the seat locking mechanism 63 therethrough. [0036] As shown in Fig. 15, an ignition coil 66 is mounted on the ignition coil support stay 20. As shown in Figs. 15 and 19, a bolt 68 is inserted through a hole 36p formed in a portion of the subframe 36 behind the upper cylindrical portions 36i, and a nut 69 is screwed on a threaded portion of the bolt 68. As shown in Figs. 15, 19, 25 and 26, a leg 70a of a resistor holder for holding a resistor 70 is put to a support lug projecting downward from a position behind the hole 36p of the subframe 36 and in a right side portion of the subframe 36 so that a hole 70b formed in the leg 70a coincides with a recess 36q formed in the support lug, a bolt 71 is inserted through the recess 36q and the hole 70b, and a nut 72 is screwed on a threaded portion of the bolt 71 to fasten the leg 70a of the resistor holder to the subframe 36. [0037] A U-shaped theft-proof hook 73 is attached by welding or the like to one side surface of the lower curved section 7d of the rear frame 7. [0038] In the embodiment shown in Figs. 1 to 26, the rear frame 7 of the main frame is a hollow member having a cross section of large dimensions. Therefore, a high reaction force of the rear wheel 4 exerted through the rear shock absorber 26 to the shock absorber support shaft 19 can surely be sustained by the rear frame 7. [0039] The aluminum subframe 36 can firmly be joined to the hollow rear frame 7 by inserting the front end portion of the subframe 36 in the rear end portion of the rear frame 7/ and fastening the subframe 36 to the rear frame 7 at three positions with the bolts 40 and 41 and nuts 42. [0040] The cast aluminum subframe 36 is lightweight and can easily be formed in a shape suitable for attaching parts including the nut 48, the body cover 50, the carrier 56, the seat locking mechanism 63, a regulator 67 and the resistor 70 to the subframe 36. The number of fitting parts is reduced, and the subframe 36 can be formed in a small size at a low cost. [0041] Since the carrier 56 is fastened together with the body cover 50 to the subframe 36, the body cover 50 and the carrier 56 can be fastened to the subframe 36 with a small number of fitting parts by reduced man-hours/ which contributes to the reduction of the costs. [0042] Since the rear portion of the fuel tank 37 is attached together with the front end portion 36a of the « subframe 36 to the rear end portion 7e of the rear frame 7, the number of parts and assembling man-hours can be reduced. [0043] The aluminum subframe 36 does not need to be finished by a surface treatment process and improves the dissipation of heat generated by the electrical equipment including the regulator 67 and the resistor 70. [REFERENCE CHARACTERS] 1 ... Motor scooter, 2 ... Main frame, 3 ... Front wheel, 4 ... Rear wheel, 5 ... Head pipe, 6 ... Down frame, 7 ... Rear frame, 8 ... Front gusset, 9 ... Rear gusset, 10 ... Main stand bracket, 11 ... Main stand, 12 ... Pivot shaft, 13 ... Extension coil spring, 14 ... Hanger sleeve, 15 ... Hanger pin, 16 ... Hanger link, 17 ... Support pin, 18 ... Bracket, 19 ... Shock absorber support shaft, 20 ... Ignition coil support stay, 21 ... Power unit, 22 ... Internal-combustion engine, 23 ... V-belt type CVT, 24 ... Reduction gear, 25 ... Power unit support shaft, 26 ... Shock absorber, 27 ... Floor support pipe, 28 ... Floor bracket, 29 ... Floor board, 30 ... Steering shaft, 31 ... Handlebar, 32 ... Front fork, 33 ... Air cleaner, 34 ... Carburetor, 35 ... Muffler, 36 ... Subframe, 37 ... Fuel tank, 38 ... Rear tank bracket, 39 ... Front tank bracket, 40 ... Bolt, 41 ... Bolt, 42 ... Nut, 43 ... Tank holding sleeve, 44 ... Bolt, 45 ... Nut, 46 ... Rear fender, 47 ... Bolt, 48 ... Nut, 49 ... Center cover, 50 ... Body cover, 51 ... Oil tank, 52 ... Battery, 53 ... Bolt, 54 ... Nut/ 55 ... Bushing/ 56 ... Carrier/ 57 ... Bolt/ 58 ... Cushioning rubber/ 59 ... Bolt/ 60 ... Nut/ 61 ... Seat, 62 ...U-shaped shackle/ 63 ... Seat locking mechanism, 64 ... Bolt/ 65 ... Nut/ 66 ... Ignition coil/ 67 ... Regulator/ 68 ... Bolt, 69 ... Nut, 70 ... Resistor, 71 ... Bolt/ 72 ... Nut, 73 ... Theft-proof hook [Claim 1] A motor scooter frame structure having a main frame, for a motor scooter having a low floor board disposed on a longitudinally middle section of the main frame, a power unit disposed under a rear section of the main frame, obliquely upwardly extending behind the floor board, and a shock absorber having one end connected to the rear section of the main frame and the other end connected to the power unit, wherein a heavy portion of the main frame between a position on the middle section of the main frame behind the floor board and a position in the rear section of the main frame at which the one end of the shock absorber is connected to the rear section of the main frame is formed from a hollow member having a high rigidity, and a portion of the rear section of the main frame extending behind the position on the rear section of the main frame at which the one end of the shock absorber is connected to the rear section of the main frame is a subframe formed by molding a lightweight material, such as aluminum, an aluminum alloy or a synthetic resin. [Claim 2] A motor scooter frame structure according to claim I/ wherein functional parts including electrical equipment are mounted on the subframe. [Claim 3] A motor scooter frame structure according to claim 1 or 2, wherein the hollow main frame has a rectangular cross section. [Claim 4] A motor scooter frame structure according to any one of claims 1 to 3, wherein the subframe is provided integrally with carrier holding stays. [Claim 5] A motor scooter frame structure according to claim 3, wherein the front end portion ox: the subframe is fixedly inserted in a rear open end portion of the hollow main frame. [Claim 6] A motor scooter frame structure according to any one of claims 1 to 4, wherein the subframe is provided with a seat locking member. [Claim 7] A motor scooter frame structure according to claim 5, wherein a front end portion of the subframe is fastened together with a fuel tank attaching parts to the main frame. 8. A motor scooter frame structure substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

Documents:

410-del-1997-abstract.pdf

410-del-1997-claims.pdf

410-del-1997-correspondence-others.pdf

410-del-1997-correspondence-po.pdf

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

410-del-1997-drawings.pdf

410-del-1997-form-1.pdf

410-del-1997-form-13.pdf

410-del-1997-form-19.pdf

410-del-1997-form-2.pdf

410-del-1997-form-4.pdf

410-del-1997-form-6.pdf

410-del-1997-gpa.pdf