Title of Invention

"REAR SHOCK ABSORBING UNIT CONNECTING STRUCTURE FOR MOTOR SCOOTER"

Abstract

To reduce the height of the position of the joining head of a rear shock absorbing unit in a motor scooter without increasing the overall height of a structure including a frame and a cross member and to simply a rear shock absorbing unit connecting structure on the frame including a bracket. [MEANS FOR SOLVING THE PROBLEM] A rear shock absorbing unit connecting structure for a motor scooter having a power unit supported under a pair of side frame members by a rear shock absorbing unit so as to swing togecher with a rear wheel in a vertical plane comprises: a cross member formed in the shape of a plate, extended between the pair of side frame members, and having a protruding part protruding upward, and a bracket attached to the lower surface of the protruding part of the cross member. An upper joining head of the rear shock absorbing unit is attached to the bracket.

Full Text

[DETAILED DESCRIPTION OF THE INVENTION] [Field of the Invention] The present invention relates to improvements in a rear shock absorbing unit connecting structure for a motor scooter and, more particularly, to a rear shock absorbing unit connecting structure that can be improved without affecting the length of a rear shock absorbing unit and the vertical dimensions of a frame. [Description of the Related Art] A motor scooter is provided with a power unit of a 'unit swing type' constructed by combining an engine, a reduction gear case, a rear wheel and the associated parts in a unit. The power unit is pivotally supported for a swing motion on a body frame, and a rear shock absorbing unit is extended between the power unit and the body of the motor scooter. A prior art connecting structure for connecting>a rear shock absorbing unit to a body is disclosed in JP-A No 62-286883. In the prior art connecting structure disclosed in the cited reference, a channel-shaped cross member is extended between lower parts of side members of a frame so as to extend obliquely upward toward the rear, a bracket is attached to an upper part of the cross member, an the upper end part of a rear shock absorbing unit is connected through the bracket to an upper part of the cross member to support the rear shock absorbing unit. In this known structure, the cross member is placed on a high part of the rear part of the frame arid hence the rear part of the body has a great height, which is not preferable. The shock absorbing unit must be capable of a proper stroke to ensure satisfactory riding quality and hence it is undesirable to reduce the length of the shock absorbing" unit. The rear shock absorbing unit must have a predetermined length. If the rear shock absorbing unit of the foregoing structure is formed in a desired length, the overall height of the vehicle is increased inevitably. [Problem to be Solved by the Invention] A structure shown in Figs. 9 to 12 is employed to limit a frame to a low height when a rear shock absorbing unit of a necessary, predetermined length is used. Referring to Figs. 9 and 10, a cross member 102 formed of a pipe is extended between side members 101 formed of pipes and forming a rear part of a frame, a bracket 103 is welded to a part of the cross member 102 near one end of the cross member 102, and an upper end part 104a of a rear shock absorbing unit 104 is joined to the bracket 103 with a bolt 105. As shown in Figs. 10 and 11, the bracket 103 is welded to the cross member 102 so as to extend obliquely rearward to secure the length of the rear shock absorbing unit 104 by attaching the upper end part of the rear shock absorbing unit 104 on the highest possible level to the bracket 103 . A part of the bracket 103 to which the rear shock absorbing unit 104 is joined is a relatively long distance behind a position of the same welded to the cross member 102. Therefore, a large torsional moment acts on the bracket 103 and hence the bracket 103 must have a great thickness to secure high rigidity and strength and must be welded to the cross member 102 in a large weld area. Therefore, the bracket 103 must have large side flanges 103b or the like to secure a large weld area in addition to a simple U-shaped part 103a. Accordingly, this structure needs the bracket 103 having a complicated construction, a great wall thickness and complicated shape. Such a bracket is difficult to form and economically disadvantageous. As is obvious from Fig. 11, the longitudinal length LI of a part of the rear shock absorbing unit 104 to be attached to the frame is great, whereby the longitudinal length of a helmet box 106 placed in that part is restricted accordingly. Only a small longitudinal space is available behind the helmet box 106, which places restrictions on the arrangement of devices to be disposed behind the helmet box 106. The present invention has been made to solve those problems and it is therefore an object of the present invention to provide a simple rear shock absorbing unit connecting structure for a motor scooter, comprising parts having simple construction and capable of being easily manufactured, and capable of reducing the number of parts, of reducing costs, of reducing the longitudinal length of a rear shock absbrbing unit connecting part to the least possible extent so that the longitudinal length is within the width of a cross member, of not affecting peripheral devices including a helmet box, of suppressing torsional moment acting on a bracket to reduce the wall thickness and weight of the bracket, and of enabling the use of a long rear shock absorbing unit without affecting the frame. [Means for Solving the Problem] A rear shock absorbing unit connecting structure stated in claim 1 for a motor scooter having a power unit supported under a pair of side frame members by a rear shock absorbing unit so as to swing together with a rear wheel in a vertical plane, comprises a cross member formed in the shape of a plate, extended between the pair of side frame members, and having a protruding part protruding upward, and a bracket attached to the lower surface of the protruding part of the cross member, in which an upper joining head of the rear shock absorbing unit is attached to the bracket. In the rear shock absorbing unit connecting structure stated in claim 1, an upper joining head of the rear shock absorbing unit is inserted in and supported on the protruding part formed in the cross member having the shape of a plate so as to protrude upward, so that the upper joining head of the rear shock absorbing unit can be disposed on a high level without increasing the height of the side members of the frame. A joint to which the upper joining head of the rear shock absorbing unit is connected is not longitudinally dislocated from a position on the cross member, and the bracket does not undergo any excessive torsional moment. Since the joint to which the upper joining head of the rear shock absorbing unit is connected is not longitudinally dislocated from a position on the cross member, the longitudinal length of a support part of the rear sock absorbing unit on the side of the frame is not great, a helmet box or the like having a large volume can be installed, and a large space is available behind the rear shock absorbing unit mounting part, which is advantageous for the arrangement of peripheral devices . In the rear shock absorbing unit connecting structure stated in claim 2, the cross member has a section similar to that of a channel opening downward. Since the cross member employed in the rear shock absorbing unit connecting structure stated in claim 2 has a section similar to that of a channel opening downward, the cross member may be a plate-shaped member instead of a pipe, the cross member has a high rigidity, arid the support part supporting the rear shock absorbing unit has a high rigidity, the cross member having the section similar to that of a channel obening downward serves as an effective base for supporting the rear shock absorbing unit . Since the upper joining head of the rear shock absorbing unit can be placed in a space defined by the upward protruding part of the cross member, the rear shock absorbing unit may have a necessary length. In the rear shock absorbing unit connecting structure stated in claim 3, a helmet box for containing a helmet is interposed between the pair of side frame members, and an oil inlet of an oil tank disposed behind the helmet box is disposed in the helmet box at a position corresponding to a position behind the rear shock absorbing unit. In the shock absorbing unit connecting structure stated in claim 3, since a space is formed behind the rear shock absorbing unit, the oil tank can be disposed behind the rear shock absorbing unit, and a large space is available in a rear part of the helmet box for easily disposing the oil inlet. Accordingly, the present invention relates to a rear shock absorbing unit connecting structure for a motor scooter having a power unit supported under a pair of side frame members by a rear shock absorbing unit so as to swing together with a rear wheel in a vertical plane, said rear shock absorbing unit connecting structure comprising: a cross member formed in the shape of a plate, extended between the pair of side frame members, and having a protruding part protruding upward; and a bracket attached to the lower surface of the protruding part of the cross member; wherein an upper joining head of the rear shock absorbing unit is attached to the bracket. [BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS] [Fig. 1] Fig. 1 is a'side view of a motor scooter. [Fig. 2] Fig. 2 is a plan view of the motor scooter of Fig. 1. [Fig. 3] Fig. 3 is a side view of a rear shock absorbing unit connecting structure in a preferred embodiment according to the present invention. [Fig. 4] Fig. 4 is a plan view of a cross member. [Fig. 5] Fig. 5 is a view taken in the direction of the arrow 5 in Fig. 4. [Fig. 6] Fig. 6 is a sectional view taken on line 6-6 in Fig. 4. [Fig. 7] Fig. 7 is an enlarged sectional side view of a connecting part connected to a rear shock absorbing unit. [Fig. 8] Fig. 8 is a sectional view of the cross member taken in the direction of the arrow 8 in Fig. 7. [Fig. 9] Figs . 9 to 12 show a rear shock absorbing unit connecting structure for a motor scooter, in which Fig. 9 is a plan view of a cross member having a connecting part. [Fig. 10] Fig. 10 is a view taken in the direction of the' arrow 10 in Fig. 9. [Fig. 11] Fig. 11 is an enlarged sectional side view of a connecting part. [Fig. 12] Fig. 12 is a view taken in the direction of the arrow 12 in Fig. 11. [Description of the Preferred Embodiments] A preferred embodiment of the present invention will be described with reference to the accompanying drawings . The drawings are expected to be seen, with reference characters set in an upright position. Fig. 1 is a side view of a motor scooter, Fig. 2 is a plan view of the motor scooter of Fig. 1, Fig. 3 is a side view of a rear shock absorbing unit connecting structure in a preferred embodiment according to the present invention, Fig. 4 is a plan view of a cross member, Fig. 5 is a view taken in the direction of the arrow 5 in Fig. 4, Fig. 6 is a sectional view taken on line 6-6 in Fig . 4 , Fig . 7 is an enlarged sectional side view of a connecting part connected to a rear shock absorbing unit, and Fig. 8 is a sectional view of the cross member taken in the direction of the arrow 8 in Fig. 7. The external appearance of a motor scooter will be described with reference to Figs. 1 and 2. In Figs. 1 and 2, indicated at 1 is a motor scooter. As shown by broken lines in Fig. 1, a down tube 2b extends obliquely upward at a large inclination from the front end of a low front part 2a of a frame 2, a head pipe 2c is joined to the upper end part of the down tube 2b, a front fork 4 supporting a front wheel 3 for steering is supported on the head pipe 2c, and a handlebar 5 is joined to the steering step 4a projecting upward from the head pipe 2c so as to extend laterally. The handlebar 5 is operated to control the front wheel 3 for steering. A middle part 2d of the frame 2 extends obliquely upward toward the rear at a large inclination from the rear end of the front part 2a of the frame 2, and a rear part 2e forming seat rails extends obliquely upward toward the rear at a small inclination from the upper end of the middle part 2d. The frame 2 has two side members extending rearward from the head pipe 2b, and the side members are connected by cross members, not shown, at proper positions. A power unit 6 including an engine 6a, a reduction gear case 6b, and such is connected by a link 6c to a part below the upper end of the middle part 2d of the frame 2 so as to be swingable. A rear wheel 7, i.e., a driving wheel, is supported on a rear part of the power unit 6. A rear shock absorbing unit 8 including a hydraulic shock absorber or the like is extended between an upper part of a rear part of the reduction gear case 6b and the rear part 2e of the frame 2. A rear shock absorbing unit connecting structure for connecting the rear shock absorbing unit 8 to the frame 2 will be describe later. As shown in Fig. 2, an air intake duct 9 is disposed laterally over the reduction gear case 6b of the power unit 6. The air intake duct 9 has an air inlet part 9a disposed on one side of the body of the motor scooter, i.e. , on the left side as viewed in Fig. 2, a main part 9b, and an intake pipe 9c provided with a resonator 9d as shown in Fig. 1 and having one end connected to the air inlet part 9a and the other end connected to the main part 9b. The main part 9b of the air intake duct 9 is connected to an air cleaner 10 disposed at a position opposite a position on the side of the reduction gear case 6b, i.e., on the left side as shown in Fig. 2. The air cleaner 10 is connected to a carburetor 11 connected by an air intake pipe lla to a suction port formed in the cylinder head of the engine. A fuel tank 12 is disposed between front parts of the side members forming the front part 2a of the frame 2 as shown in Figs. 1 and 2, and an oil tank 13 is disposed between rear parts of the side members forming the rear part 2e of the frame 2 as shown in Fig. 1. A battery 14 is held in front of the head pipe 2c on the head pipe 2c. The front side of the head pipe 2c and the sides of the motor scooter are covered with a front cover 15 so as to cover the battery 14, the rear side of the head pipe 2c and the rear surface of the down tube 2b are covered with a steering stem cover 16. The handlebar 5 is surrounded by a handle cover 17. A light unit 18 including a headlight and turn signal lamps is placed on a front part of the handle cover 17, and an instrument unit 19 is placed on an upper part of the handle cover 17. A front fender 20 is extended over an upper part of the front wheel 3. A low floor 21 is extended rearward from the lower parts of the front cover 15 and the steering stem cover 16, and a foot rest on which driver's feed rest is formed on the' floor 21. A seat post cover 22 is extended upward from a rear part of the floor 21. A rear cover 23 is extended rearward from behind the seat post cover 22 . The middle part 2d and the rear part 2e of the frame 2 are covered entirely by the covers 22 and 23. A seat 24, is disposed over the seat post cover 22 and the rear cover 23. The seat 24 is a longitudinally elongate tandem seat for two passengers, having a front part 24a for a driver and a rear part 24b for a fellow passenger. A rear carrier 25 is disposed behind the seat 24, and a U-shaped grip 26 for the passenger on the rear part 24b of the seat 24 is attached to a front part of the rear carrier 25. A helmet box 27 is disposed below the seat 24. The helmet box 27 is covered with the seat post cover 22 and the rear cover 23. A rear part of the helmet box 27 is shown in Fig. 7. The helmet box 27 has an open upper end. The seat 24 covers the open upper end of the helmet box 27 and is supported at its front end by a hinge. The seat 24 is turned on the hinge so as to cover and to open the open upper end of the helmet box 27. Thus, the seat serves as a cover for the helmet box 27. An upper part and a rear part of the rear wheel 7 are covered with a rear fender 28. As shown in Fig. 1, the rear part 2e of the frame 2 is gently inclined upward toward the rear. As shown in Figs. 4, 5 and 8, the rear part 22e of the frame 2 is formed by extending side members 31, i.e., pipes, at a predetermined lateral distance from each other. In Fig. 4, the upper side corresponds to the rear side of the motor scooter, and the lower side corresponds to the front side of the motor scooter. A cross member 32 is extended between middle parts of the side members 31. As shown in Figs . 4 and 5, the cross member 32 is formed by pressing a plate in the shape of a channel and has a cross section resembling an inverted letter U. The cross member 32 has an upper wall 32a , front and rear side walls 32b and 32c, and flanges 32d extending toward the front and toward the rear from the side walls 32b and 32c, respectively. Thus the cross member 32 can easily formed by pressing a plate in the shape of a channel and has a high rigidity. A circular connecting parts 32e are formed in the opposite ends of the cross member 32 . The circular connecting parts 32e are welded to the respective upper half parts of predetermined parts of the side members 31 . As shown in Figs . 3 and 4, trapezoidal gussets 32f are formed integrally with the cross member 32 at the base ends of the connecting1 parts 32e, and the gussets 32f are welded to the inside surfaces of predetermined parts of the side members 31. Middle parts of the flanges 32d of the cross member 32 are extended toward the front and toward the rear to form support parts 32g and 32h. The front end of the rear fender 28 is attached to the support part 32h, and a part of he bottom wall of the helmet box 27 is attached to the support part 32g. A part of the cross member 32 near one of the side members 31, i.e., the left side member 31 (the side member 31 on the right side in Fig. 5 showing the cross member as viewed from the front side, and the side member 31 on the left side in Fig. 8 showing the cross member 32 as viewed from the rear side) is bent to form an upward protruding part 33. Parts of the upper wall, the side walls and the flanges forming the protruding part 3 3 are bent in upward convex curves, respectively, and are continuous with other parts to form the cross member in an integral part. A an upper wall 34a of a bracket 34 having the shape of resembling the inverted letter U as viewed from the front is welded to the lower surface of the upper wall of the protruding part 33. The cross member 33 having the protruding part 33 may be a pressed member formed by pressing a steel plate or an aluminum alloy casting. The lower end part 8a of the rear shock absorbing unit 8 is joined to a lug 6d formed on an upper rear part of the reduction gear case 6b. As shown in Figs. 3 and 7, the rear shock absorbing unit 8 comprises a hydraulic shock absorber 8b, a rod 8d, a cushioning spring 8c, a bump stop rubber 8e and the associated parts. A joining head 8f attached to the upper end of the rod 8d is inserted from below in a space between the side walls 34b of the bracket 34 welded to the lower surface of the upper wall of the protruding part 33 of the cross member 32, a bolt is passed laterally through the side walls 34b and the joining head 8f, and a nut 36 is screwed on the bolt 35 to hold the connecting head 8f on the bracket 34. A through hole 36 is formed in a part of the upper wall of the cross member 32 forming the left side wall of the protruding part 33 as shown in Figs. 4 and 8, and the bolt 35 is passed from the left side through the opening 36, the side wall 34b of the bracket 34, the joining head 8f of the rear shock absorbing unit 8 and the other side wall 34b of the bracket 34 to hold the joining head 8f inserted in the space between the side walls 34b of the bracket 34 on the bracket 34 . As shown in Fig. 3, a stay 37 for supporting the carrier 25 is attached to the rear end parts of the side members 31 forming the rear part 2e of the frame 2. In Figs. 4 and 5, indicated at 38 is a clip for holding a wiring harness. Thus, the joining head 8f of the rear shock absorbing unit 8 is joined to the bracket 34 disposed in the upward protruding part 33 formed in a part of the cross member biased on one side. Since the bracket 34 is attached to the upward protruding part 33 having the shape of a channel, the bracket 34 is not longitudinally dislocated from a position on the cross member 32 and is disposed on a high level. Accordingly, the position of the joining head 8f is raised from the cross member 32 by a distance corresponding the height of the upward protruding part 33 , so that the height of the side members 31 and the cross member 32 need not be increased when the rear shock absorbing unit 8 is formed in a predetermined length. Since the bracket 34 is not longitudinally dislocated from a position on the cross member, the joining head 8f of the rear shock absorbing unit 8 is located right below the cross member 32. Therefore, unlike the prior art, torsional moment does not acting on a bracket by the rear shock absorbing unit 8 . The load to the bracket 34 is less than that of the vertical direction, resulting in implementing the wall thickness reduction, the simple structure, the facility of forming, and the facility of welding to the cross member 32 . As shown in Fig. 7, the back wall 27a of the helmet box 27 lies in front of the connecting part of the cross bar 32 where the rear shock absorbing unit 8 is joined to the bracket 34. The longitudinal length L of the connecting part is short as compared with that of the connecting part of the conventional shock absorbing unit connecting structure and hence the helmet box 27 can be formed in a great longitudinal length. Since the connecting part is formed in the relatively short longitudinal length, the longitudinal length of a space behind the connecting part can be increased accordingly. Therefore, the oil tank 13 of a large capacity necessary when the engine is a two-stroke cycle engine can be disposed behind the rear shock absorber connecting part, and a concave shelf 27b can be formed behind the rear wall 27a of the helmet box 27 integrally with the rear wall 27a, an L-shaped oil supply pipe 13a connected to the oil tank 13 can be extended through the bottom wall 27c of the concave shelf 27b and an oil inlet part 13b can be disposed on the concave shelf 27b. Thus, the oil inlet of the oil tank 13 can be placed in a large space behind the helmet box 27. The helmet box 27 is covered with the seat 24 . The seat 24 is raised to gain access to the oil inlet part 13b, a cap is removed from the oil inlet part 13b, and oil is poured into the oil tank 13. The large space in which the oil inlet part 13b is placed facilitate oil pouring work. In Fig. 7, a tongue 28b projecting from the front part 28a of the rear fender 28 is fastened with a screw 28c to the support part 32h projecting rearward from a middle part of the cross member 32. [Effect of the Invention] The present invention exercises the following effects. According to claim 1, the cross member formed by processing a plate is extended between the pair of side frame members and has the protruding part protruding upward, the bracket is attached to the lower surface of the protruding part of the cross member, the upper joining head of the rear shock absorbing unit is attached to the bracket. The upper joining head of the rear shock absorbing unit can be attached to the lower surface of the upper wall of the upward protruding part of the cross member, the side members of the frame can be extended on a low level, the cross member can be extended between the cross member on the same level as the side members of the frame, and the upper end of the rear shock absorbing unit can be held on a high level. Accordingly, the rear shock absorbing unit of a necessary length can be used in combination with the fr'ame on a low level and hence the rear shock absorbing unit is able to exercise a satisfactory cushioning function and the motor scooter has a satisfactory riding quality. The connecting part where the rear shock absorbing unit is connected to the cross member is not longitudinally dislocated from the cross member, the rear shock absorbing unit does not apply any torsional moment to the bracket, load on the bracket is relatively small, the thickness of the walls of the bracket may be small, and the shape and the construction of the bracket may be simple, the welding area of the bracket is small as compared with that of the conventional bracket, the bracket can easily be formed and can easily be joined to the cross member, the rear shock absorbing unit connecting structure needs a reduced number of component parts, and is lightweight and inexpensive. According to claim 2, in the rear shock absorbing unit connecting structure stated in claim 1, the cross member has a section similar to that of a channel opening downward, the cross member is a plate-shaped member instead of a pipe, the cross member having a high rigidity is a pressed member made by pressing a steel plate or a casting made by casting an aluminum alloy, the cross member having the section similar to that of a channel opening downward serves as an effective base for supporting the rear shock absorbing unit, the upper joining head of the rear shock absorbing unit and the bracket can be placed in a space opening downward, the upper end of the rear shock absorbing unit can be placed in the open section, and the rear shock absorbing unit having a necessary, sufficient length can be used because the upper end of the rear shock absorbing unit can be placed in the open section and the connecting part of the cross member is protruded upward. According to claim 3, in the rear shock absorbing unit connecting structure stated in claim 1, the helmet box for containing a helmet is interposed between the pair of side frame members, and the oil inlet of the oil tank disposed behind the helmet box is disposed in the helmet box at a position corresponding to a position behind the rear shock absorbing unit. Therefore, the helmet box disposed near the rear shock absorbing unit can be formed in a sufficient volume, a space can be formed behind the rear shock absorbing unit to dispose the oil tank behind the rear shock absorbing unit, and a large space is available in the rear part of the helmet box for easily disposing the oil inlet. [REFERENCE CHARACTERS] 1 ... Motor scooter, 2 ... Frame, 6 ... Power unit, 7 ... Rear wheel, 8 ... Rear shock absorbing unit, 8f ... Joining head of the rear shock absorbing unit, 13 ... Oil tank, 13b . . . Oil inlet part, 27 ... Helmet box, 31 ... Side member, 32 ... Cross member, 33 ... Upward protruding part, 34 ... Bracket of the rear shock absorbing unit WE CLAIM: 1. A rear shock absorbing unit connecting structure for a motor scooter (1) having a power unit (6) supported under a pair of side frame members by a rear shock absorbing unit (8) so as to swing together with a rear wheel (7) in a vertical plane, said rear shock absorbing unit connecting structure comprising: a cross member (32) formed in the shape of a plate, extended between the pair of side frame members, and having a protruding part protruding upward; and a bracket (34) attached to the lower surface of the protruding part (33) of the cross member (32); wherein an upper joining head of the rear shock absorbing unit is attached to the bracket (34). 2. The rear shock absorbing unit connecting structure for a motor scooter as claimed in claim 1, wherein the cross member (32) has a section similar to that of a channel opening downward. 3 The rear shock absorbing unit connecting structure for a motor scooter as claimed in claim 1, wherein a helmet box (27) for containing a helmet is interposed between the pair of side frame members, and an oil inlet (136) of an oil tank disposed behind the helmet box (27) is disposed in the helmet box at a position corresponding to a position behind the rear shock absorbing unit (8). 4. A rear shock absorbing unit connecting structure for a motor scooter substantially as herein described with reference to and illustrated in the accompanying drawings

Documents:

3272-DEL-1998-Abstract.pdf

3272-del-1998-claims.pdf

3272-del-1998-correspondence-others.pdf

3272-del-1998-correspondence-po.pdf

3272-del-1998-description (complete).pdf

3272-del-1998-drawings.pdf

3272-del-1998-form-1.pdf

3272-del-1998-form-13.pdf

3272-del-1998-form-19.pdf

3272-del-1998-form-2.pdf

3272-del-1998-form-4.pdf

3272-del-1998-form-6.pdf

3272-del-1998-gpa.pdf

3272-del-1998-petition-137.pdf

3272-del-1998-petition-138.pdf