FIELD OF THE INVENTION

This invention relates to a motorcycle frame, and more particularly to a layout for the motorcycle frame that provides sufficient space for mounting an induction system and simplifies the routing of an intake passageway for the engine, the frame further eliminates the need of an external carrier and pillion support, by integrating the carrier and pillion support with the frame.

BACKGROUND

Scooters and mopeds more particularly step through type mainly used for commuting or business purpose generally comprises a backbone type frame. The frame comprises a steering head pipe that supports a front fork. The frame also comprises a main frame member that extends rearward from the steering head pipe.

In such vehicles, the main frame member typically forms the primary frame structure. Brackets can be provided along an intermediate portion of the main frame member and the engine can be suspended from those brackets. As can be imagined, the brackets generally protrude downward from the main frame member whereas a floorboard is secured to the upward portion of the main frame member.

In this type of arrangement mounting of the induction system and routing of intake passage to the engine becomes difficult owing to space restriction and also the routing passageway is obstructed by the floorboard. Further an external carrier and a pillion handle is secured to the rear side of the main frame member wherein, the carrier provides framework for mounting the seat.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to overcome one or more of the drawbacks mentioned above.

The present invention utilizes a frame comprising of three sections; a mainframe member, a split mainframe member and a sub frame in place of a mono tube main frame member while retaining the structural layout of the frame. The main frame member protrudes obliquely downwards and rearward from the head pipe, subsequently, forming into the split main frame member that is in shape of a fork with two branch members running parallel to each other and united at one end. The split main frame member runs further rearwards but parallel to the ground, finally the split main frame member is attached to the sub frame that defines the rear structure of the vehicle. The space between the branch members of the split main frame member is utilized for mounting the induction system and providing the direct route for engine intake passageway. The large space makes it easier to arrange the induction system comprising the air filter; carburettor and the interconnecting passages between them further the intake passageway for the engine is directly routed. This arrangement results in maintaining sufficient vehicle rigidity at the same time, it is possible to obtain a vehicle frame with a large degree of freedom with respect to layout of the above-described components. The frame further eliminates the need for an external carrier and pillion support by integrating the carrier and pillion support with the sub frame.

Other objects and further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from the detailed description given herein below and the accompanying drawings which are given by way of illustration only, and thus, are not limitative of the present invention, and wherein:

Figure 1A is a left side view of a moped, in accordance with the prior art.

Figure 1B is a left side view, illustrating a backbone type frame used in the moped depicted in figure 1 along with a preferred arrangement of power unit.

Figure 2 is a left side view of a moped, in accordance with the invention;

Figure 3 is a left side view of a vehicle frame as per a preferred embodiment of the present invention.

Figure 4 depicts the main frame element as per a preferred embodiment of the invention.

Figure 5 depicts the split main frame element as per a preferred embodiment of the invention.

Figure 6 depicts the side view of the sub frame as per a preferred embodiment of the invention.

Figure 7 is a top view of the seat rails as per a preferred embodiment of the invention.

Figure 8 is a top view of the integrated carrier and the seat rail section of the frame as per a preferred embodiment of the invention.

Figure9 is a top view of the vehicle frame as per a preferred embodiment of the invention.

Figure 10 is a top view of the vehicle frame as per a preferred embodiment of the invention, illustrating an arrangement of components.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

With reference to Figures 1A, and 1B a prior art moped 01 preferably comprises a backbone type frame 02 is illustrated; the steering head pipe 03 is located at the front end of the frame 02. The steering head pipe 03 supports the front wheel 04 through the front fork 05 along with the handle bar 06 to steer the vehicle. A main frame member 07 composed of single tubular element, extends; firstly obliquely downwards and rearwards from the steering head pipe 03 secondly rearwards parallel to the ground forming first horizontal section of the frame, thirdly obliquely upwards and rearwards and finally, rearwards parallel to the ground forming second horizontal section of the frame. A fuel tank 08 is mounted on the front part that comes obliquely downwards and an engine 09 is suspended at an intermediate location of the first horizontal section of the frame. Above the engine 09 a floorboard 10 is secured to the main frame member 07.

Further a rear wheel 11 is secured to the frame 02 via a swing arm 12 and a shock absorber element 13.

However, in this type of arrangement mounting of the induction system that may comprise an air filter, a carburettor and interconnections between them becomes difficult due to space constraints further, the routing of intake from the induction system to engine becomes difficult as engine 09 is suspended from the main frame member 07 in downwards direction and the path is obstructed by the floorboard 10 generally positioned above the engine 09. Further, an external carrier and pillion support 14 is secured to the main frame member 07 by welding or bolting or any other appropriate means.
While the illustrated vehicle 01 depicts a moped, certain features, aspects and advantages of the present invention may also find utility with other types of vehicles. In particular, certain features, aspects and advantages of the present invention may find utility with other vehicles having a low-slung engine that is supported by a central frame member.

With reference to Figures 2 - Figure 10 in an embodiment of the present invention, as illustrated, the vehicle 15 uses, the frame 40 comprises of three sections the main frame member 17, the split main frame member 18 and the sub frame 39 along with the steering head pipe 16 that is located at the front end of the frame 40 that supports a front wheel 22 via a front fork 23 along with the handle bar 21 for steering the vehicle 15. A main frame member 17 in the present embodiment extends obliquely downwards and rearwards of the steering head pipe 16 where subsequently it is formed into the split main frame member 18 that is in shape of fork with two branch members 18A, 18B running parallel to each other and united at forked end. The parallel branch members 18A, 18B extends further rearwards parallel to the ground, finally the split main frame member 18 is secured to the sub frame 39 that defines the rear structure of the vehicle 15. The main frame member 17 can be secured to the steering head pipe 16 in any suitable manner. In one configuration, the main frame member 17 is welded to the steering head pipe 16 from the forked end side. The main frame member 17 along with the split main frame member 18 preferably defines the primary structure of the frame and can be made of any suitable material, such as, for example but without limitation, a steel pipe having a generally circular cross-section. In some configurations, the main frame member 17 and the split main frame member 18 can have the shape of a box in cross section and/or can be formed by welding together components formed by press forming or extrusion, for example. Other materials and shapes also can be used. Moreover, the main frame member 17 and the split frame member 18 need not be formed of one single section but can also be formed of a two separate sections secured to each other in an appropriate manner.

Towards the rear side, a right seat rail 39A and a left seat rail 39B extend rearward parallel to the ground. The seat rails 39, 39B are formed of a single member 39 forming a loop wherein the rear transverse portion 19 of the loop is adapted to be used as a pillion support thus eliminating the need for an external pillion support. Gussets are provided at the location where the horizontal seat rail 39A, 39B bends down and the open ends extends obliquely downwards whereby, they are secured to the rear ends of the parallel running branch members 18A, 18B of said split main frame member 18 correspondingly. The gusset 25 is located where seat rail 39B bends the other corresponding gusset for seat rail 39A is not shown in figure. One gusset 31 also provides arrangement for pivotally mounting shock absorber element 20 to the frame 40 whereas; the other end of the shock absorber 20 is pivotally secured to the swing arms 28.

The seat rails 39A, 39B can be secured to the split main frame member 18 in any suitable manner. In the illustrated configuration, the open ends of the said loop are welded to the parallel running branch members 18A, 18B of the split main frame member 18. Gussets (25, 31, 32 and 41) are provided at the joining to provide strength. The Gussets (25, 32 and 41) also provides holes for mounting engine along with the brackets provided for mounting the engine. The gusset 25 is provided where seat rail 39B joins with the branch member 18B, the gusset provided 39A joins with 18A is on other side and is not shown in figure.

The seat rails 39A, 39B preferably are spaced from each other in the transverse (i.e., vehicle width) direction having plurality of cross members secured between them. The present embodiment uses three cross members 42A, 42B and 42C. The cross members are provided with grooves (one such groove indicated by reference numeral 21) for bolting the seat 30 thus eliminating the need for an external carrier. Additional seat support 37 is also provided to mount a separate seat 29 for rider.

The open ends of the said seat rails 39A, 39B after being secured to the parallel running branch members 18A, 18B of the split main frame member 18 further, extends downwards and a swing arm bracket 36 designed and configured to support a swing arm 28 is secured to the extended seat rails. The swing arm 28 extends rearward of the swing arm bracket 28, and a rear wheel 27 is supported at the rear end of the swing arm 28.

Preferably, rear portion of the swing arm 28 is connected to the frame 40 with a shock absorber 20.

The extended seat rails 39A, 39B also supports the stand 26 used to support the vehicle 15 while parking.

The space 45, defined between parallel running branch members 18A, 18B of the split main frame member 18 houses the components of induction system such as a carburettor 34, and an air cleaner 33 further,

as the floorboard can be placed above the components, the intake passageway 44 for engine is routed directly, and further the components such as carburettor 34 are protected from dust, at the same time can be accessed easily by removing the foot board. Thus, the invention provides in line mounting of the induction system with simplified routing of intake passageway 44 for the engine 35.

The engine 35 is mounted through the brackets 32, 41 and the hole provided on gusset 25. The bracket 32 extends longitudinally from the swing arm bracket 36 towards the forward direction of vehicle 15 whereas the bracket 41 protrudes downwards from an intermediate location of the branch member 18B. The same arrangement is made on the other side at the corresponding position on branch member 18A.

A fuel tank 24 that is supported on the main frame member 17, can also be supported on the seat rails 39A, 39B preferably located on the front halves (i.e. after the bent) of the illustrated seat rails 39A, 39B, whereas, the seat 30 extends from a position generally vertically above on the horizontal section of the seat rails 39A, 39B. The mounting of fuel tank 24 at the rear portion of the vehicle frame 40 also enables to have larger floorboard area.

According to the present invention, it is possible to obtain a vehicle frame with a large degree of freedom with respect to layout of the above-described components. The present invention is not limited to the above-described embodiments, and various modifications and adaptations are possible within the spirit of the present invention. For example, it is possible to have other components, arranged inside the space.

The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.

WHAT IS CLAIMED IS:

What is claimed is:

1) A frame structure of a motorcycle comprising:

a main frame member extending downwards from a head pipe towards rear of the motorcycle subsequently forming into a first and a second main frame member spaced in transverse direction and extending towards rear of the motorcycle and passes over an engine;
a sub frame attached to rear end of said main frame member and extending downwardly to clutch with a plurality of holding bracket;

wherein, a plurality of mounting bracket is integrated with the first and the second main frame members, and a support structure is integrated with the sub frame configured to support said sub frame member;

wherein, the sub frame extends towards its rear end defining rear structure of the motorcycle, and said downward extended sub frame supports a motorcycle stand assembly.

2) The frame structure, as claimed in claim 1, wherein the sub frame extends rearwards rising gradually at an angle supported by said supporting structure and extending rearwards defining rear structure of the motorcycle.

3) The frame structure, as claimed in claim 1, wherein the sub frame is formed of a continuous tubular structure forming a loop such that sections of the tubular structure forming the loop are spaced in transverse direction, with open ends attached to the main frame member along with a first set of gussets.

4) The frame structure, as claimed in claim 3, wherein the first set of gussets further comprises of the plurality of mounting bracket configured to support engine mounting.

5) The frame structure, as claimed in claim 3, wherein the loop comprises a transverse rear portion adapted to form a pillion support.

6) The frame structure, as claimed in claim 1, wherein the sub frame further comprises a second set of gussets at the downward bent section having said supporting structure configured to support shock absorber mounting.

7) The frame structure, as claimed in claim 1, wherein the holding bracket is configured to pivotally support a swing arm.

8) The frame structure, as claimed in claim 1, wherein the sub frame comprises a plurality of cross member secured between transverse sections of tubular structure to define rear end of the frame structure.

9) The frame structure, as claimed in claim 8, wherein the plurality of cross members comprises a plurality of grooves configured to support a first seat mounting.

10) The frame structure, as claimed in claim 1, wherein the sub frame comprises a vertical rising portion to form a post like structure configured to support a second seat mounting.