TECHNICAL FIELD

The subject matter described herein, in general, relates to a two-wheeled vehicle and in particular relates to a frame structure of a two-wheeled vehicle.

BACKGROUND

A frame structure acts as a skeleton or backbone for any vehicle by providing strength to the vehicle. The strength of the frame structure defines the reliability of the vehicle. The functions of the frame structure of a two-wheeled vehicle can be broadly divided into two types: static and dynamic. In order to fulfill the static functionality, the frame structure not only supports the weight of various components of the two-wheeled vehicle, such as engine, fuel tank, and accessories like lights, indicators but also of the rider and pillion. The frame structure has provisions for mounting different components and accessories like engine, seats, lights, indicators, suspension system, and electrical components such as a battery and switches.

The dynamic functions of the frame structure include providing adequate structural stiffness and precise steerability to the vehicle. The frame structure also dampens mechanical vibrations and isolates shocks while driving under various road conditions. Moreover, the frame structure provides safety and comfort to the driver and minimizes damage to the vehicle in case of an accident.

The frame structure is one of the major contributors to overall weight of the vehicle. A vehicle with heavy frame structure has higher fuel consumption, in turn, has poor fuel economy. Efforts are being made to reduce the weight of the frame structure in order to increase the fuel economy of the vehicle. However, the challenge lies in weight reduction without any compromise on safety and strength of the vehicle.

Conventionally, the frame structure of the two-wheeled vehicle is made out of extruded metal tubes having closed cross sections such as a round, oval, square, or rectangular. The frame structure cannot be made light by reducing the cross-sectional area or thickness of the tubes forming the frame structure as that would be a compromise on the structural stiffness and the strength of the frame structure. The reduction in the cross-sectional thickness of the tubes may also lead to welding abnormalities, thus again adding up to the structural weakness. One can also use lighter material, such as light metals like aluminum or any other metallic composition, for the construction of the frame structure. However, that would lead to an increase in the overall cost of the vehicle.

SUMMARY

The subject matter described herein is directed to a frame structure of a two-wheeled vehicle. In one embodiment, the frame structure includes a head tube along with a number of structural members. A set of front structural members is attached to the head tube at a front end and extends in a downward direction of the vehicle. Each of the front structural members is attached to an engine mounting bracket. Further, a set of upper structural members is attached to the front structural member, and extends in a rear direction of the vehicle. The upper structural members are also attached to the front structural member by means of a set of side structural members. The upper structural members are further connected to a rear seat support at a rear end of the vehicle. All the structural members of the frame structure are formed as open cross-sectional members to ensure weight reduction.

In a typical frame structure, due to non-uniform distribution of load, there exist certain high load bearing localized areas demanding reinforcement to ensure desired strength and stability. The high load bearing localized areas include various locations such as, a location of attachment of front structural members with the head tube, a location of attachment of the upper structural members with the front structural member and an engine mounting location on the front structural members. These high load bearing localized areas are reinforced with one or more stiffeners in order to ensure desired stiffness and strength of the frame structure.

The employment of structural members having open cross section ensures reduction in over all weight of the vehicle and in turn increases fuel economy of the vehicle. Moreover, the stiffeners provide requisite strength and stability to the vehicle. The frame structure of present subject matter is also economical and easy to manufacture.

These and other features, aspects, and advantages of the present subject matter will become better understood with reference to the following description and appended claims. This summary is provided to introduce a selection of concepts in a simplified form. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.

BRIEF DESCRIPTION OF DRAWINGS

The above and other features, aspects, and advantages of the subject matter will become better understood with regard to the following description, appended claims, and accompanying drawings where:

Fig. 1 illustrates an isometric view of an exemplary frame structure of a two-wheeled vehicle, according to an embodiment of present subject matter.

Fig. 2 illustrates a side view of a front portion of the exemplary frame structure of Fig. 1 depicting cross sections of structural members, according to an embodiment of present subject matter.

Fig. 3 illustrates an isometric view of the front portion of the exemplary frame structure of Fig. 1 depicting exemplary stiffeners provided at various exemplary high load bearing localized areas, according to an embodiment of present subject matter..

DETAILED DESCRIPTION

A frame structure of a two-wheeled vehicle is described herein. The frame structure includes a head tube and a number of structural members. The one or more of the structural members of the frame structure have open cross sections, such as a C-shaped cross-section, an reshaped cross-section, an I-shaped cross-section or any other open cross-section known in the art, in order to reduce the weight, of the two-wheeled vehicle. The reduction in weight is achieved without affecting the cost, strength or stiffness of the frame structure. In order to ensure requisite strength and stiffness, various stiffeners are provided at various high load bearing localized areas, based on the load distribution on each of the structural members of the frame structure.

Fig. 1 illustrates an isometric view of an exemplary frame structure 100 of a two-wheeled vehicle. For instance, and by no way limiting the scope of the present subject matter, the two-wheeler of the present subject matter is a motorcycle. The frame structure 100 is designed to possess suitable configuration in conformity with the design of the vehicle. As used herein, the terms "front, "rear", "side", "downward", "upward", correspond to the position assumed by a rider of the two-wheeled vehicle with respect to the direction in which he is facing. The frame structure 100 comprises of a head tube 105 and a number of inter-linked structural members. For

example, and by no way of limitation, the frame structure 100 may include a set of front structural members 108 including a main body member 110 and a lower structural member 115, and a set of engine mounting brackets 118 including a front engine mounting bracket 120 and a rear engine mounting bracket 125. The frame structure 100 further includes a set of upper structural members 128 including a first upper structural member 130 and a second upper structural member 135, a set of side structural members 138 including a first side structural member 140 and a second side structural member 145, and a rear seat support 150.

Each of the main body member 110 and the lower structural member 115 are attached to the head tube 105 at one end and are extended in a downward direction of the two-wheeled vehicle. The main body member 110 and the lower structural member 115 are configured to accommodate an engine (not shown in Fig. 1) of the two-wheeled vehicle. In order to support the engine, the front engine mounting bracket 120 is mounted at a free end of the lower structural member 115 and the rear engine mounting bracket 125 is mounted at other free end of the main body member 110.

The first upper structural member 130 and the second upper structural member 135 of the frame structure 100 are fixed to the main body member 110 and are extended towards rear direction of the two-wheeled vehicle. The first side structural member 140 is attached to the rear engine mounting bracket 125 on one end and to the first upper structural member 130 on another end. Similarly, the second side structural member 145 is attached to the rear engine mounting bracket 125 on one end and to the second upper structural member 135 on another end. The rear seat support 150 is disposed at rear ends of the first upper structural member 130 and the second upper structural member 135 for supporting the seat of the two-wheeled vehicle.

In order to reduce the weight of the frame structure 100, one or more of the structural members of the frame structure 100, such as the main body member 110, the lower structural member 115, the first upper structural member 130, the second upper structural member 135, the first side structural members 140, and the second side structural member 145 have open cross-sections. In one embodiment, for example, the structural members of the frame structure 100 have a C-shaped cross-section. In another embodiment, the structural members of the frame structure 100 can have an L-shaped or an I-shaped cross-section, or any other open cross-section known in the art or a combination thereof. The reduction in the cross-sectional area, and hence the reduction in the amount of material used, in the construction of the frame structure 100 leads to a reduction in the overall weight of the two-wheeled vehicle. This reduction in weight not only helps in achieving cost reduction, but also ensures better fuel economy. In order to ensure that the reduction in cross sectional area in no way leads to reduction in the stiffness and strength of the frame structure 100 additional stiffeners (not shown in the figure) are provided at high load bearing localized areas as described below. Thus, weight reduction is achieved without any loss of strength or stiffness of the frame structure.

The high load bearing localized areas are indentified by determining the load distribution along the various structural members of the frame structure 100. In a typical scenario, the load distribution is not uniform. This non-uniform load distribution demands more strength and stiffness at the high load bearing localized areas, as the high load bearing localized areas are prone to early failure under loading as compared to other areas of the frame structure 100. The high load bearing localized areas are reinforced with the stiffeners to compensate for higher load, and for any loss of stiffness and strength due to employment of open section structural members. The stiffeners are small pieces of high strength materials attached to the structural members of the frame structure 100. The stiffeners may be bolted, welded or fastened by any other means to the structural members.

Fig. 2 illustrates a side view of a front portion 200 of the frame structure 100 depicting cross-sections of the main body member 110 and the lower structural member 115 along a plane A-A'. As shown herein, the main body member 110 and the lower structural member 115 have C-shaped cross sections 210 and 215, respectively. Rest of the structural members of the frame structure 100, other than those mentioned hereinbefore can have any combinations of open cross-sections known in the art.

Fig. 3 illustrates an isometric view of the front portion 200 of the frame structure 100 depicting various stiffeners provided at various high load bearing localized areas. In one embodiment, a front stiffener 300 is disposed at a point of attachment of the main body member 110 and the lower structural member 115 with the head tube 105. Likewise, a front bridge stiffener 305 is attached to the main body member 110 on one end and to the lower structural member 115 on another end. The attachment is made such that the front bridge stiffener 305 lies at the center of the front portion 200 of the frame structure 100. In addition to the front stiffener 300 and the front bridge stiffener 305, a front engine mounting stiffener 310 is disposed at a free end of the lower structural member 115 and where the front engine mounting bracket 120 is attached. A joint stiffener 315 is also disposed on the main body member 110 and at a location where the first upper structural member 130 and the second upper structural member 135 are attached to the main body member 110. In one implementation, the various stiffeners such as the front stiffener 300, the front bridge stiffener 305, the front engine mounting stiffener 310, and the joint stiffener 315 have open cross-sections similar to the structural members of the frame structure 100. In another implementation, all the stiffeners have open cross-sections different from that of structural members. One can understand that the structural members and the stiffeners can have any combination of open cross-sections as long they satisfy the underlying design requirement of the frame structure 100.

The previously described embodiment of the subject matter and its equivalents thereof has many advantages, including those which are described herein. The frame structure is lighter than any conventional frame structure, thereby decreasing the fuel consumption and increasing efficiency of the two-wheeled vehicle. In addition, identifying high load-bearing localized areas in the frame structure fulfill the static and dynamic stability requirements of the two-wheeled vehicle. Additional stiffeners at these high load bearing localized areas help to achieve the desired strength and stiffness required for the reliable functioning of the two-wheeled vehicle. These stiffeners also help in dampening the vibrations produced in the two-wheeled vehicle.

While certain features of the claimed subject matter have been illustrated and described herein, many modifications, substitutions, changes, and equivalents will now occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes that fall within the true spirit of the claimed subject matter.

I/We claim:

1. A frame structure (100) of a two-wheeled vehicle, said frame structure (100) comprising:

a head tube (105);

a plurality of front structural members (108) coupled to said head tube;

a plurality of upper structural members (128) wherein said upper structural members (128) are attached to at least one of said front structural members (108);

a plurality of side structural members (138) attaching said upper structural members (128) to at least one of said front structural members (108);

a rear seat support (150) attached to the rear end of said upper structural members (128);

characterized in that,

one or more of said front structural members (108), said upper structural members (128), and said side structural members (138) have open cross section; and

one or more stiffeners (300, 305, 310, and, 315) are provided at high load bearing localized areas of said frame structure (100).

2. The frame structure (100) as claimed in claim 1, wherein said high load bearing localized areas are one or more of: a location of attachment of said front structural members (108) with said head tube (105), a location of attachment of said upper structural members (128) with said front structural member (108), or a location on at least one said front structural members (108), where a engine is mounted.

3. The frame structure (100) as claimed in claim 1, wherein said front structural members (108) comprise a main body member (110) and a lower structural member (115).

4. The frame structure (100) as claimed in claim 3, wherein said main body member (110) is attached to a rear engine mounting bracket (125), and said lower structural member is attached to a front engine mounting bracket (120).

5. The frame structure (100) as claimed in claim 1, wherein said side structural members (138) are attached to a rear engine mounting bracket (125).

6. The frame structure (100) as claimed in claim 1, wherein one or more of said front structural members (108), upper structural members (128), and side structural members (138) have cross section of C-shape, L-shape, I-shape, T-shape or a combination thereof.

7. The frame structure (100) as claimed in claim 1, wherein said stiffeners (300, 305, 310, and, 315) have open cross section.

8. The frame structure (100) as claimed in claim 1, wherein said stiffeners (300, 305, 310, and, 315) have close cross section.

9. The frame structure (100) as claimed in claim 1, wherein said stiffeners (300, 305, 310, and, 315) have cross section of C-shape, L-shape, I-shape, T-shape or a combination thereof.