Field of the Invention

This invention relates to a step through type motorcycle or moped frame comprising a power unit along with a functional component suspended from a main frame member that extends rearwards from steering head pipe.

Background

Motorcycles and mopeds, more particularly step through type, mainly used for commuting or business purpose generally comprises a backbone type frame. The frame comprises a head pipe that supports a front fork. The frame also comprises a main frame member that extends rearwards from the steering head pipe. The main frame member is generally formed of a single tubular element.

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 a power unit can be suspended from those brackets. As can be imagined, the brackets generally protrude downward from the main frame member. As such, the lower edges of the brackets extend longitudinally along a top face of the crankcase.

Thus, a space is defined between the top face of the crankcase and the main frame member, and this space is generally the same as the height of the brackets. When the motorcycle is viewed from the side, this space is generally enclosed by the brackets.

Accordingly, if a functional component for the power unit, such as a starter motor, were to be positioned on the crankcase of the engine in the proximity of the brackets, the brackets would necessarily be displaced upward by an amount corresponding to the volume or vertical dimension of the functional component. Moreover, footrests for the rider in such configurations are usually attached to the bottom surface of the power unit casing that limits the gap between power unit and the ground. The upward displacement thus, results in an increase in distance between the crankcase and the main frame member to accommodate the functional component.

The vertical position of the power unit above the road surface that is termed as ground clearance is normally determined by, for example, a trade-off with the elevation changes in the road surface or banking angle of the road over which the vehicle can be ridden without causing the engine to bottom on the road surface. Thus, in order to maintain the engine at a desired distance from the ground, the spacing between the ground and the main frame member tends to be enlarged but at the same time the overall height of the vehicle cannot be increased above a certain limit.

Summary of the Invention

It is, therefore, an object of certain embodiments of the present invention to provide a motorcycle that allows the main frame member to be lowered while still suspending a power unit and providing arrangement for accommodating a functional component between a case of the engine and the main frame member. The invention further provides a unique arrangement for footrests so that ground clearance is further enhanced.

Accordingly, one aspect of the present invention involves a motorcycle that comprises a steering head pipe with a main frame member extending rearward from the steering head pipe. The power unit comprises a functional component and a case. The main frame member comprises a relief designed such that the desired strength of main frame member is not compromised. The case of the power unit and the relief on the main frame member together define a space that accommodates the functional component. Thus, the invention addresses the above-mentioned problems without increasing the spacing between the main frame member and ground. Further, the footrests are accommodated so as the ground clearance is further enhanced to accommodate the functional component in case maximum relief that can be provided is not sufficient.

Brief Description of Drawings

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

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 1C is a detailed view, illustrating the preferred arrangement of power unit of Figure 1B.

Figure 2 depicts a relief provided in the motorcycle frame as per an embodiment of the invention;

Figure 3 is a cross-sectional view the relief along the line AA.

Figure 4 depicts an arrangement of power unit and the space created by the relief.

Figure 5 depicts a functional component of the engine placed in the space created as per an embodiment of the invention.

Figure 6 depicts the left side footrest mounting arrangement.

Figure 7 depicts the left side footrest along with the mounting shaft.

Figure 8 depicts the right side footrest mounting arrangement.

Figure 9 depicts the right side footrest along with the mounting shaft.

Detailed Description of the Preferred Embodiment

With reference to Figures 1A and 1B and 1C, a moped 01 preferably comprising a backbone type frame is illustrated. While the illustrated vehicle comprises a moped or a motorcycle, 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.

As 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 extends firstly, obliquely rearwards and downwards from the steering head pipe 03, secondly, rearwards parallel to the ground forming front horizontal structure of the frame, thirdly, obliquely upwards and rearwards and finally, rearwards parallel to the ground forming rear horizontal section. A fuel tank 08 is mounted on the section of main frame member that comes obliquely downwards and an engine 09 is suspended at an intermediate position of the front horizontal section. Above the engine 09 a floorboard 10 is secured to the front horizontal section of the main frame member 07.

The main frame member 07 can be secured to the steering head pipe 03 in any suitable manner. The main frame member 07 preferably defines the primary structure of the frame 02 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 can have the shape of a box in cross section. Other materials and shapes also can be used.

Further, a swing arm bracket 15 is secured to the rear portion of the main frame member 07 designed and configured to supports a swing arm 12. The swing arm bracket 15 protrudes downwards from the main frame member 07. The swing arm 12 extends rearward of the swing arm bracket 15, and a rear wheel 11 is supported at the rear end of the swing arm 12. Preferably, at least a portion of the swing arm 12 is connected to the frame 02 through a shock absorber 13 or the like.

With reference to Figure 2 and 3 a relief 14 is provided on the bottom surface of the main frame member 07. The size and location of the relief 14 is in accordance with the functional component to be placed. Further the relief is made at certain angle forming a semi elliptical structure.

With continued reference to Figure 2, plurality of engine brackets 16,17 and 18 are secured to the front horizontal section of the main frame member 07 and the swing arm bracket 15 that extends downwards from the rear portion of the main frame member 07.

The first engine bracket 16 preferably depends downward from an intermediate portion of the front horizontal section of the main frame member 07.

With continued reference to Figure 2 and 3, the illustrated second 17 and third 18 engine brackets are located on the front end of the swing arm bracket 15. As shown in Figure 2, the second 17 and third 18 engine brackets projects in longitudinal direction from the front end of the swing arm bracket 15.

With reference now to Figure 4, the illustrated engine comprises a crankcase 19 and a cylinder 20 that is connected to the front end of the crankcase 19. In one configuration, the cylinder 20 preferably protrudes forward from a forward end of the crankcase 19 in a generally horizontal orientation such that it has an axis that extends in a longitudinal direction of the engine 09.

Referring back to Figure 4, the crankcase 19 preferably is suspended from the main frame member 07 in any suitable manner using the said engine brackets (16, 17, and 18). In an embodiment the crankcase 19 may comprises a first, a second and a third brackets corresponding to the engine brackets; the first bracket protrudes upward from the forward end of a top face of the crankcase. The second and third brackets 17, 18 protrude longitudinally from the rearward end of the top face of the crankcase. The first bracket is secured with the first engine bracket 16 and second and third brackets with corresponding second and third engine brackets 17, 18 by any suitable mechanism. Other configurations also are possible.

With reference to Figure 4 a space S advantageously is defined between the relief provided on the main frame member 07 and the top face of the crankcase 19.

With reference to Figure 5, the starter motor 21 is an example of a functional component of an engine and can be located directly on top face of the crankcase 19. Other functional components also can be used. The illustrated starter motor 19 comprises a cylindrical motor housing. The motor housing supports the rotational shaft and houses a rotor and a stator (not shown). The motor housing and the space S are advantageously sized and configured to accommodate the starter motor within the space S.

In the illustrated configuration, the upper face 22 of the crankcase 19 may comprises a motor support portion at its upper forward end. Advantageously, the motor support portion is located such that it comes immediately below the relief 14 when engine 09 is mounted. As mentioned above, the space S is available in this region. The motor support portion extends upward from the top face 22 of the crankcase 19 in the illustrated configuration. The motor housing of the starter motor can be secured to the motor support portion via a bolt.

Preferably, the starter motor 21 is disposed in a generally horizontal attitude. More preferably, the starter motor extends transversely relative to the vehicle (i.e., side to side).
In other words, the starter motor is disposed in the space S defined between the top face 22 of the crankcase 19 and the relief 14.

With reference to Figures 6, 7, 8 and 9, in the present embodiment of the invention one of the footrests 24 for the rider is attached to the main frame member 07 through shaft 23 routed from above the crankcase 19 whereas the second footrest 26 is attached on one side of the crankcase 19 through another shaft 25 routed from the side of crankcase thus, no footrest is attached to the bottom surface and moreover no shaft is routed from below the engine which further increases the ground clearance.

As illustrated, the starter motor 21 advantageously is located in the space S defined between the relief 14 and the top face of the crankcase 22. Accordingly, the starter motor 21 can be accommodated in the space created above the crankcase 19 that results from the relief 14 so that the main frame member 07 need not be displaced upward to accommodate the functional component, such as the starter motor 21. This allows the main frame member 07 to be lowered to the lowest possible position based upon the desired amount of ground clearance for the engine.

Further the footrests 24, 26 are accommodated in a manner so that the ground clearance is not compromised and provides additional room for the larger functional component if required.

Although the present invention has been described in terms of a certain embodiment, other embodiments apparent to those of ordinary skill in the art also are within the scope of this invention. Thus, various changes and modifications may be made without departing from the spirit and scope of the invention. For instance, various components may be repositioned as desired. Moreover, not all of the features, aspects and advantages are necessarily required to practice the present invention.
Accordingly, the scope of the present invention is intended to be defined only by the claims that follow.

Claims

What is claimed is:

1. A motorcycle comprising a steering head pipe, a main frame member extending firstly, obliquely downwards secondly, rearwards parallel to the ground and thirdly, obliquely upwards, and finally, rearwards parallel to the ground, said main frame member is formed of a single tubular structure, a power unit comprising a case, the case being suspended from the main frame member, the case of the power unit comprising a top face, the top face being spaced from the main frame member along a longitudinally

extending segment of the main frame member;
wherein, a functional component of the power unit being located between the top face of the case and the main frame member, wherein the main frame member comprises a relief having a semi elliptical structure; and

wherein, a first footrest being located towards a right face of the case and attached to the main frame member, a second footrest located towards a left face of the case and attached to a face of the case.

2. The motorcycle of claim 1, wherein the main frame member is parallel to the ground, upper surface of the case and the relief on main frame member defining a space, and the functional component is located in the space.

3. The motorcycle of claim 2, wherein the relief extends from 10% to 30% of the main frame element width.

4. The motorcycle of claim 2, wherein the power unit comprises an engine, the engine comprising a cylinder and a crankshaft, the crankshaft being positioned generally within the case, the cylinder projecting forward of a forward end of the case, and the functional component comprising a starter motor, the starter motor extending in a vehicle width direction at a location generally above the crankshaft.

5. The motorcycle according to claim 2, wherein the functional component extends in a transverse direction of the motorcycle.