DESC:TECHNICAL FIELD
[0001] The present subject matter relates generally to a monocoque structure for a motor vehicle and more particularly to a monocoque structure for a two-wheeled motor vehicle.

BACKGROUND
[0002] Generally, a two-wheeled vehicle may have a frame structure, or a monocoque structure that bears the load of the vehicle. Typically, the frame structure is formed by a tubular section(s) or castings, which acts as skeleton, for bearing loads and for mounting vehicle parts. Plurality of panels cover the frame structure. Whereas, the monocoque structure is integral part of the body, which acts as the load bearing part and constitutes of mountings for vehicle parts. In a step-through type vehicle, with either of the aforesaid structures, a step-through space is provided for a user to rest his feet and acting as utility space.

BRIEF DESCRIPTION OF DRAWINGS
[0003] The detailed description of the present subject matter is described with reference to the accompanying figures. Same numbers are used throughout the drawings to reference like features and components.
[0004] Fig. 1 illustrates a left side view of an exemplary vehicle, in accordance with an embodiment of present subject matter.
[0005] Fig. 2 (a) illustrates a left side perspective view of a monocoque structure, in accordance with an embodiment of the present subject matter.
[0006] Fig. 2 (b) depicts a plan view of the monocoque structure depicted in Fig. 2 (a).
[0007] Fig. 2 (c) illustrates a cross-sectional view of a bridge member.
[0008] Fig. 3 (a) depicts a left side view of monocoque structure, in accordance with another embodiment of the present subject matter.
[0009] Fig. 3 (b) illustrates a cross-sectional view of the monocoque structure depicted in Fig. 3 (a)
[00010] Fig. 4 depicts a rear view of a front portion of a monocoque structure, in accordance with yet another embodiment of the present subject matter.

DETAILED DESCRIPTION
[00011] Generally, in a monocoque structure for a step-through type vehicle, some reinforced parts, or a single protruded-up floorboard in the middle, or a single piece panels, or plurality of above combinations are provided. Further, in a monocoque structure known in the art, a support beam is provided at lateral centre and extends in longitudinal direction. Also, the style panel(s) extend till the support beam. Moreover, in monocoque structures known in the art, utility space on the vehicle is compromised. Also, styling of the vehicle becomes complex. The aforementioned limitations make the structure known in the art low convenience, making the structure costly and resulting in poor styling. Further, the performance of the vehicle is affected.
[00012] Hence, an objective of the present subject matter is to provide a monocoque structure for a two-wheeled vehicle. The monocoque structure includes a first side railing, and a second side railing being spaced apart in a vehicle width direction and disposed substantially at a vehicle width end(s). The first side railing and the second side railing are connected in a lateral direction by a plurality of bridge member(s) disposed therebetween.
[00013] According to one feature of the present subject matter, the monocoque structure is provided with a flat floorboard disposed at the step-through portion of the vehicle. It is an advantage of the present subject matter that the utility spaced is improved. It is yet another advantage that the need for a tubular structural member is eliminated.
[00014] According to one aspect, the monocoque structure enables in providing improved styling as the side railings function as structural members at the same time acts as aesthetic components. It is an advantage that the need for additional body panels is reduced. It is a further advantage that the weight of the vehicle is improved.
[00015] Another aspect is cost is reduced. It is yet another advantage that the ride comfort is improved.
[00016] It is yet another aspect that the side railings enclose one or more parts of the vehicle. It is yet one another aspect that the monocoque structure includes a housing panel supported by the side railings. It is a feature that the housing panel is capable of enclosing one or more parts of vehicle including a storage unit. It is an additional feature that the housing panel supports a seat assembly of the vehicle.
[00017] It is yet another additional feature each of side railing includes two or more sub-railings. It is another advantage that each sub-railing is selected from rigid material including any known metal or polymer or fiber or fiber reinforced plastic.
[00018] In an embodiment, the present subject matter relates to a monocoque structure with a step-through type structure and the monocoque structure acts as load bearing part. The monocoque structure comprises a left hand (LH) side railing, and a right hand (RH) side railing extending downward from below a steering assembly towards a floor board portion and inclinedly rearwardly from the floor board portion towards a tail lamp of the vehicle. The second side railing is a second side railing and the first side railing is first side railing. Hereinafter, the terms second side railing and second side railing are interchangeably used. Similarly, the terms first side railing and the first side railing are interchangeably used. The second side railing and the first side railing are spaced apart in a lateral direction and disposed substantially at a lateral end(s). The second side railing and the first side railings are together referred to as pair of side railings. In an embodiment, the pair of side railings are made of sheets of any known metal.
[00019] Furthermore, the monocoque structures comprises a plurality of bridge member(s) connecting the pair of railing(s) and disposed therebetween. The pair of side railings being connected to each other by a lateral end portion(s) of the plurality of bridge member(s). The plurality of bridge members being made of sheet metal. Further, in an embodiment, a flat floorboard is mounted to the pair of side railings and being disposed at the floorboard portion. The floorboard being made of sheet metal and the floorboard comprising a substantially horizontal cross-section. In another embodiment, at least one of the plurality of bridge member(s) support at least a portion of the floorboard. In an embodiment, the floorboard is made of sheet metal that is welded to the pair of side railings.
[00020] In addition, a housing panel is provided on the pair of side railings and the housing panel being supported by at least a portion of the pair of side railings. The housing panel is disposed at rearwardly of the floorboard portion and extending towards the tail lamp of the monocoque structure. The housing panel is secured to the pair of side railings.
[00021] In another embodiment, the first side railing is formed by two or more first side sub-railing(s) and the second side railing is formed by two or more second side sub-railing(s). The second side sub-railing(s), and the first side sub-railing(s) are preferably made of metal. In another embodiment, one or more of said sub-railings are made of plastic or the like, wherein the railing sub-railings made of plastic are disposed at low stress regions. This sub-railings formed of plastic reduce weight.
[00022] In an embodiment, the first side railing and second side railing are formed by first side sub-railing(s) and second side sub-railing(s), respectively. In an embodiment, the sub-railing(s) are having asymmetric length. In other words, a sub-railing disposed on one side is having a length different from the length of an adjacent sub-railing disposed on other side. Further, each of the first side sub-railing(s), and second side sub-railing(s) may have different section properties and being adapted to work with corresponding load mounted at said sub-railing(s) of the monocoque structure.
[00023] In an embodiment, the plurality of bridge members includes one or more front bridge member(s), one or more railing bridge members, and one or more rear bridge members. The one or more front bridge members connect a front portion of the pair of side railing members. One or more rear bridge member(s) of the plurality of bridge members connects a rear portion of the pair of side railing bridge members. The one or more railing bridge members connect and strengthen the monocoque structure along the longitudinal direction of the vehicle.
[00024] In an embodiment, the plurality of bridge members includes at least one bridge having a closed cross section. In other words, the at least one bridge, when taken a cross-section in longitudinal direction, having a box shaped or a closed cross-section. This provides strength to the bridge member to withstand torsional stresses acting on the vehicle at the particular location.
[00025] In an embodiment, the monocoque structure is provided with a leg shield connecting the pair of side railings and being disposed forwardly of the floorboard portion. The leg shield provides additional structural support to the monocoque structure. The leg shield being made of sheet metal and welded to the pair of side railings. In an embodiment, a plastic leg shield is used and being affixed to the pair of side railings.
[00026] In an embodiment, the railing bridge member(s) of the monocoque structure are adapted to swingably connect a swing arm. In addition, an engine assembly is mounted to the swing arm that is swingably connected to railing bridge member(s). In another embodiment, the railing bridge member(s) are adapted to mount an engine assembly that is swingably connected. In addition, a toggle link may be used to connect the swing arm, or the engine assembly to the monocoque structure.
[00027] In an embodiment, the rear portion of the pair of side railing side railings and the housing panel is adapted to accommodate various vehicle parts that include a storage compartment, a fuel tank. Further, in an embodiment a seat assembly is mounted to the housing panel of monocoque structure. Furthermore, the housing panel is capable of accommodating a pillion handle that is secured to the rear bridge member.
[00028] In an embodiment, the monocoque structure is provided with plurality of mounting points that enable in mounting of an attachable-detachable storage unit or the like. For example, the storage unit may be fastened or snap-fitted. Further, the pair of side railings are adapted to accommodate an all-round guard. The all-round guard extends substantially along the pair of side railings of the monocoque structure. The all-round guard may be of elastic material or the like. In an embodiment, the all-round guard may be of metal.
[00029] The monocoque of the present subject having the second side railing and the first side railing being disposed substantially at a lateral end(s), improves the ease of manufacture, for example ease of welding of said sub-railings. Further, the monocoque structure has pair of side railings being disposed at the vehicle width ends, forming styling parts of the vehicle, and also eliminating need for support beam at the centre.
[00030] The aforesaid and other advantages of the present subject matter would be described in detail in conjunction with the figures in the following description.
[00031] Arrows wherever provided in the top right corner of figure(s) in the drawings depicts direction with respect to the vehicle, wherein an arrow F denotes front direction, an arrow R indicates rear direction, an arrow Up denotes upward direction, an arrow Dw denotes downward direction, an arrow RH denotes right side, and an arrow LH denotes left side.
[00032] Fig. 1 illustrates an exemplary step-through type vehicle with a monocoque structure, in accordance with an embodiment of the present subject matter. The vehicle 100 has a monocoque structure 200 (shown in Fig. 2 (a)) that acts as load bearing member of the vehicle 100. A handlebar assembly 105 is rotatably connected to a front wheel 110 through the monocoque structure 200 at a front portion F. One or more front fork(s) 115 connect the front wheel 110 to the handlebar assembly 105. An engine assembly 120 is swingably connected to the monocoque structure. Further, the engine assembly 120 is functionally connected to a rear wheel 125 through a transmission assembly (not shown). The rear wheel 125 is connected to the monocoque structure 200 through one or more rear suspension(s) 130. A seat assembly 135 is positioned above engine assembly 120. A pillion handle140 is provided on the rear portion R of the vehicle 100.
[00033] A front fender 145 is provided at the front portion for covering at least a portion of the front wheel 110. A rear fender 150 is covering at least a portion of the rear wheel 125, which is positioned below a fuel tank (not shown). Further, the vehicle 100 comprises of plurality of electrical/electronic components including a headlight 155, a tail lamp 160, a battery (not shown), a transistor controlled ignition (TCI) unit (not shown), an alternator (not shown), and a starter motor (not shown). A front panel 165 acts as a windshield for deflecting air and a leg shield 170 is provided at an anterior portion of the step-through space. In an embodiment, an electric motor (not shown) is hub mounted to the rear wheel 125.
[00034] Fig. 2 (a) illustrates a left side perspective view of a monocoque structure for a step-through type vehicle, in accordance with an embodiment of the present subject matter. The monocoque structure 200 comprises a RH side railing 205A and a LH side railing 205B, together referred to as pair of side railings 205A, 205B. Hereinafter, the terms RH side railing 205A and first side railing 205A are interchangeably used. Similarly, the terms LH side railing 205B and second side railing 205B are interchangeably used. The first side railing 205A and the second side railing 205B extend from a below a steering assembly 105, extending downwards towards a floorboard portion FP and then inclinedly rearward from the floorboard portion FP towards a tail lamp 160. The monocoque structure 200 defines a floorboard portion FP, which is otherwise referred to as a step-through portion. In one embodiment, The pair of side railing 205A, 205B are made of a rigid material including any known sheet metal. Further, the monocoque structure 200 includes plurality of bridge members 210A, 210B, 215, and 220 connecting the second side railing 205A and the first side railing 205B, therebetween. The plurality of bridge members 210A, 210B, 215, and 220 are distributively disposed in a longitudinal direction F-R of the vehicle. The pair of side railings 205A, 205B are connected to the plurality of bridge members 210A, 210B, 215, and 220 by lateral end portion(s). In addition, the monocoque structure 200 includes a housing panel 225 disposed rearwardly of the floorboard portion FP, disposed on at least a portion of the first side railing 205A and the second side railing 205B. In an embodiment, the housing panel 225 is having a hollow structure having a first opening in the upward portion and a second opening in the downward portion. The downward portion of the housing panel 225 is welded or the like to an upper portion of the pair of side railings 205A, 205B. In an embodiment, the housing panel 225 is made of shell metal.
[00035] Fig 2 (b) depicts a plan view of the monocoque structure depicted in Fig. 2 (a). The first side railing 205A and the second side railing 205B extend from below the handle bar assembly in downward direction towards the floorboard portion FP and extends inclinedly rearward towards the tail lamp from the floorboard portion FP, towards the tail lamp 160. The first side railing 205A and the second side railing 205B are disposed substantially at the vehicle width end(s) W1, W2. The vehicle width ends W1, W2 define the width of the vehicle 100. Also, as the monocoque structure 200 forms the structural member and body member of the vehicle 100, the width of the monocoque structure 200 is substantially equal to the width of the vehicle 100. Further, a lateral end portion(s) of the plurality of bridge members 210A, 210B, 215, and 220 connect the pair of side railings 205A, 205B, therebetween. The first side railing 205A, the second side railing 205B, and the plurality of bridge members 210A, 210B, 215, and 220 are made of sheet metal. The lateral end portion(s) of the plurality of bridge members 210A, 210B, 215, and 220 are welded or the like to the pair of side railing member(s) 205A, 205B. Further, a flat floorboard 235, which is made of sheet metal, being disposed at the floor board portion FP and is welded to the pair of side railings 205A, 205B therebetween. Further, a railing bridge member 215 of the plurality of bridge members supports at least a portion of the floorboard 235. In another embodiment, the railing bridge member 215 being adapted for connecting a swing arm using a toggle link (not shown), wherein said swing arm is mounted with an engine assembly (not shown). In an embodiment, the railing bridge member(s) 215 is adapted to mount an engine assembly 120.
[00036] In the present embodiment, the plurality of bridge member(s) includes one or more front bridge member(s) 210A, 210B. The one or more front bridge member(s) 210A, 210B connects the first side railing 205A, and the second side railing 205B in the front portion F. In an embodiment, the one or more front bridge member(s) 210A, 210B are capable of rotatably supporting a steering assembly (not shown) including the handle bar assembly 105. The one or more front bridge member(s) 210A, 210B are welded or the like to the pair of side railings 205A, 205B, therebetween. In an embodiment, a first front bridge member 210A connects at least a portion of the pair of side railings 205A, 205B at an upper portion of the front portion F. A second front bridge member 210B connects at least a portion of the pair of side railings 205A, 205B in a lower portion in the front portion F. The first front bridge member 210A and the second front bridge member 210B are positioned with a spacing and a support tube 240 being disposed therebetween. The support tube 240 enables pivotal connection of the handle bar assembly 105 with the front wheel 110 through the steering assembly (not shown).
[00037] Furthermore, the plurality of bridge member(s) includes one or more rear bridge member(s) 220 provided at the rear portion R of the pair of side railings 205A, 205B connecting the pair of side railings 205A, 205B, therebetween. The rear bridge member(s) 220 enables strengthening of fatigue points in the rear portion R of the monocoque structure 200. Also, the rear bridge member 220 supports a utility box disposed below the seat assembly 135. In another embodiment, the lateral end(s) of the rear bridge member(s) 220 are welded to the hosing assembly 225, thereby supporting at least a portion of the housing panel 225.
[00038] Fig. 2 (c) depicts a cross-sectional view of the monocoque structure taken at the floorboard portion, in accordance with an embodiment of the present subject matter. Fig. 2 (c) depicts the cross-section without the pair of side railings 205A, 205B. The floorboard 235 is supported by railing bridge member(s) 215 that is made of sheet metal. In an embodiment, the railing bridge member 215 is having a box shaped cross-section. In other words, the railing bridge member 215 includes a closed shape cross-section, when taken in the longitudinal direction F-R. The railing bridge member(s) 215 is provided with one or more routing provision(s) 245. For example, holes are formed in the longitudinal direction in the railing bridge member(s). This one or more routing provision(s) 245 enable routing of wiring, piping or cabling along the longitudinal direction of the vehicle. For example, electrical and mechanical cables and wiring harness from the handle bar assembly 105 to the engine assembly 120. In another embodiment, routing provisions are selectively provided on the plurality of bridge member(s).
[00039] Fig. 3 (a) depicts a left side view of a monocoque structure, in accordance with another embodiment of the present subject matter. In this particular embodiment, two or more second side sub-railings 305BA, 305BB, 305BC are welded together to form the second side railing 305B and a first side railing 305A is formed by two or more first side sub-railings (not shown), which are welded together. The terms second side railings and the second side sub-railings are interchangeably referred to as LH side railing and LH side sub-railing, respectively. Similarly, the terms first side railings and the first side sub-railings are interchangeably referred to as RH side railing and RH side sub-railing, respectively. A first LH side sub-railing 305BA extends from below the handle bar assembly 105 towards the floorboard portion FP of the monocoque structure 300. The second LH side sub-railing 305BB extend along the longitudinal direction at the floorboard portion FP. The third LH side sub-railing 305BC extends from floorboard portion FP towards the tail lamp 160. Similarly, the first side railing (not shown) is formed by a first RH side sub-railing, a second RH side sub-railing, and a third RH side sub-railing.
[00040] The first LH side sub-railing 305BA and the first RH side sub-railing are connected by a first front bridge member 310A and the second front bridge member 310B. Further, a first railing bridge member 315A and a second railing bridge member 315B connects the second LH side sub-railing 305BB and the second RH side sub-railing. Further, the monocoque structure 300 of the present subject matter enables creation of space below the floorboard 235, which can be used for accommodating vehicular parts like fuel tank or batteries. Further, the third LH side railing 305BC and the third RH side railings are connected by one or more rear bridge member(s) 320 extending in the lateral direction RH-LH.
[00041] Fig. 3 (b) illustrates a cross-sectional view of the monocoque structure depicted in Fig. 3 (a), taken along the Z-Z’ axis. In an embodiment, the housing panel 325 is made of metal with thickness lower than the thickness of the pair of side railings 305A, 305B. In an embodiment, the housing panel 325 is made of first metal and the pair of side railings 305A, 305B is made of second metal, wherein the first metal and the second metal are any of the known metals. In such a case, the housing panel is welded or the like to the pair of side railings. In an embodiment, one or more sub-railings of the pair of side railings 305A, 305B are made of plastic or the like. The one or more sub-railings are used at points with low loads of the vehicle and one or more sub-railings made of plastic are either fastened or plastic welded or the like in the monocoque structure 300.
[00042] Fig. 4 depicts a rear view of front portion of a monocoque structure, in accordance with an embodiment of the present subject matter. The portion of the first side railing 205A and the second side railing 205B are provide with plurality of mounting member 250A, 250B, 250C, 250D. The plurality of mounting members enables 250A, 250B, 250C, 250D mounting of an attachable-detachable storage unit (not shown). Further, the leg shield 230 supports the storage unit.
[00043] Further, the pair of side railings 205A, 205B are adapted to accommodate an all-round guard 260. The all-round guard 260 extends being disposed substantially at the lateral end(s), which is at left side and right side, and extends along the pair of side railings 205A, 205B of the monocoque structure. In an embodiment, the guard 260 extends along an outer periphery of the pair of railings 205A, 205B and the guard 260 protects the pair of railings 205A, 205B. In a preferred embodiment, the all-round guard 260 is made of an elastic material or the like and the guard 260 is detachably-attached.
[00044] It is to be understood that the aspects of the embodiments are not necessarily limited to the features described herein. Many modifications and variations of the present subject matter are possible in the light of above disclosure. Therefore, within the scope of claims of the present subject matter, the present disclosure may be practiced other than as specifically described.
,CLAIMS:I/We claim:
1. A monocoque structure (200, 300) for a two-wheeled vehicle (100) having a floor portion (FP), said monocoque structure (200, 300) comprising:
a first side railing (205A, 305A), and a second side railing (205B, 305B) extending downward from a handle bar assembly (105) towards said floor portion (FP) and inclinedly rearwardly from said floor portion (FP) towards a tail lamp (160) of the vehicle (100),
wherein
said first side railing (205A, 305A) and said second side railing (205B, 305B) are spaced apart in a vehicle width direction (RH-LH) and disposed substantially at a vehicle width end(s) (W1, W2), and
said first side railing (205A, 305A) and the second side railing (205B, 305B) being connected by a plurality of bridge member(s) (210A, 201B, 215, and 220, 310A, 310B, 315A, 315B, and 320) disposed therebetween.
2. The monocoque structure (300) of claim 1, wherein said first side railing (305A) includes one or more first side sub-railing(s) affixed to each other and the second side railing (305B) includes one or more second side sub-railing(s) (305BA, 305BB, 305BC) affixed to each other.
3. The monocoque structure (200, 300) of claim 1, wherein said plurality of bridge member(s) (210A, 201B, 215, and 220, 310A, 310B, 315A, 315B, and 320) are distributively disposed in a longitudinal direction (F-R) of the vehicle (100) and said plurality of bridge member(s) (210A, 201B, 215, and 220, 310A, 310B, 315A, 315B, and 320) includes at least one bridge member (215) having a closed cross-section.
4. The monocoque structure (200) of claim 1, wherein said monocoque structure (200) includes a floor board (235) having substantially flat top surface and said floor board (235) is supported by at least one of said first side railing (205A), said second side railing(205B), and a railing bridge member (215) of said plurality of bridge member(s) (210A, 201B, 215, and 220) .
5. The monocoque structure (200, 300) of claim 1 further comprises a housing panel (225, 325) is securely affixed to a top peripheral portion to said first side railing (205A, 305A) and said second side railing (205B, 305B), and said housing panel (225, 325) being disposed rearward of the floor board portion (FP) of the vehicle (100).
6. The monocoque structure (200) of claim 1, wherein said plurality of bridge member(s) (210A, 201B, 215, and 220) includes a railing bridge member (215) having one or more routing provision(s) (245), therein, for routing at least one of electrical cables, mechanical cables, or hoses.
7. The monocoque structure (200) of claim 1, wherein said plurality of bridge member(s) (210A, 201B, 215, and 220) includes one or more front bridge member(s) (210A, 210B) disposed in a front portion (F) of the monocoque structure (200) and said one or more front bridge member(s) (210A, 210B) is capable of supporting a steering assembly.
8. The monocoque structure (200) of claim 1, wherein said plurality of bridge member(s) (210A, 201B, 215, and 220) includes one or more rear bridge member(s) (220) capable of supporting a utility box.
9. The monocoque structure (200) of claim 1, wherein said first side railings (205A), and said second side railing (205B) are adapted to accommodate an all-round guard (260) disposed to an outer periphery of said first side railing (205A) and said second side railing (205B).
10. The monocoque structure (200, 300) of claim 1, wherein said monocoque structure (200, 300) of the two-wheeled vehicle (100) swingably supports a power unit (120) includes at least one of an internal combustion and a traction motor.