DESC:TECHNICAL FIELD
[0001] The present subject matter relates generally to a two-wheeled motor vehicle and more particularly to two-wheeled motor vehicles with step-through type frame assembly.
BACKGROUND
[0002] Generally, in a two-wheeled saddle-ride type vehicle a frame assembly extends rearward from a head tube. Moreover, in the two-wheeled vehicle with a step-through type frame assembly, a step-through space is provided. The frame assembly acts as a skeleton for the vehicle that supports the vehicle loads. A front portion of the frame assembly is connected to a front wheel through one or more front suspension(s). The frame assembly extends rearwardly of the vehicle, where a rear wheel is connected to the frame assembly through one or more rear suspension(s). An internal combustion (IC) engine is mounted to the frame assembly of the vehicle. The IC engine is functionally connected to the rear wheel, which provides the forward motion to the vehicle. Typically, plurality of panels is mounted to the frame assembly of the vehicle that covers various vehicle components.
BRIEF DESCRIPTION OF THE 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 (a) illustrates a left side view of an exemplary two-wheeled motor vehicle, in accordance with an embodiment of the present subject matter.
[0005] Fig. 1 (b) illustrates a left side view of a frame assembly of a two-wheeled motor vehicle, in accordance with an embodiment of the present subject matter.
[0006] Fig. 2 (a) illustrates a left side view of a front portion of a two-wheeled motor vehicle, in accordance with an embodiment of the present subject matter.
[0007] Fig. 2 (b) depicts a left side view of a frame assembly, in accordance with an embodiment of the present subject matter.
[0008] Fig. 3 (a) illustrates a left side view of a rear portion of a two-wheeled motor vehicle, in accordance with another embodiment of the present subject matter.
[0009] Fig. 3 (b) depicts left side view of the frame assembly, in accordance with an embodiment of the present subject matter.
[00010] Fig. 3 (c) depicts a left side perspective view, in accordance with an embodiment of the present subject matter.
[00011] Fig. 4 depicts a top perspective view of the vehicle, in accordance with yet an embodiment of the present subject matter.
DETAILED DESCRIPTION
[00012] Generally, in a two-wheeled vehicle with a mono-tube frame assembly, a single tubular structure extends rearwardly from the head tube towards a rear portion of the vehicle. Various vehicle components that include the engine assembly, a fuel tank, a seat assembly, and a seat assembly are mounted to the frame assembly. Generally, the vehicle has a naked appearance. Moreover, majority of the vehicle components are exposed to the atmosphere.
[00013] Generally, the vehicle is compactly packaged with the vehicle components. Especially, the engine assembly is mounted to the frame assembly below the step-through space of the frame assembly. The engine assembly includes an internal combustion (IC) engine and a starter system. Vehicles, now a days are provided with electric start mechanisms for providing ease of operation to the user. The starter system helps in cranking the engine. The starter system includes a starter motor that is powered by an auxiliary power source. Further, the vehicle may have additional components including a control unit and vehicle control unit. All the electrical and electronic components are connected through wiring harness. However, the compact single tubular structure frame and the compact packaging of the vehicle components makes accommodating vehicle components complex. For example, the electrical components including auxiliary power source has to be kept in proximity to the engine assembly to reduce the wiring harness. In addition, the vehicle components like auxiliary power source should be kept away from being exposed to atmosphere, rain, or dirt, for their effective functioning. Furthermore, the aforementioned problem is to be solved without comprising utility space of the vehicle.
[00014] Hence, it is an object of the present subject matter to provide a two-wheeled vehicle with a frame assembly. The vehicle is provided with an auxiliary storage unit capable of accommodating vehicle component(s) including electrical components like auxiliary power source and the like thereby providing optimum packaging and optimum wiring harness.
[00015] According to another object, the utility space on the vehicle is not compromised. It is an advantage that the vehicle utility space is retained and the vehicle layout is also retained.
[00016] According to another aspect, the auxiliary storage unit is capable of accommodating auxiliary source power source or the like that are in proximity to the power unit. It is an advantage that the wiring harness for connecting the electrical components like auxiliary power source is reduced by optimally providing the auxiliary storage unit. It is another advantage that the optimum wiring harness reduced copper losses thereby improving the performance of the system.
[00017] The term electrical components is not to be construed limiting, wherein said electrical components includes electronic components like electronic control unit, anti-lock braking system, or ignition unit.
[00018] It is an additional advantage that the cost of the system is reduced. Further, the auxiliary power source or the like is protected from being exposed to atmosphere. It is an advantage that the auxiliary storage unit is disposed in proximity to the power unit and the same time the power unit mounting space is retained.
[00019] In an embodiment, in accordance with the present subject matter, a two-wheeled motor vehicle has a step-through type frame assembly. In an embodiment, the frame assembly is a mono-tube type frame assembly that includes a head tube, a main tube that extends rearwardly downward, a down tube extending from a rear portion of the main tube and a rear tube extending inclinedly rearward from a rear portion of the down tube. In an embodiment, the frame assembly is a tubular structure having either a hollow or a solid cross-section. The frame assembly is having a centre line that passes substantially along circumferential centre of cross-section of the frame assembly. The frame assembly may have a regular cross-section such as circular, or triangular, or square, or rectangle or an irregular shape.
[00020] In an embodiment, the vehicle is provided with a power unit. The power unit includes at least one of an internal combustion engine, or an electric motor or the like. The power unit is being mounted to the down tube of the frame assembly. In an embodiment, the power unit is a two-stroke type with at least one combustion chamber. In another embodiment, a four-stroke type with at least one combustion chamber is used. The IC engine is functionally connected to a rear wheel, which is rotatably mounted to a swing arm. The swing arm is swingably connected to the frame assembly. A transmission system transfers the power generated by the IC engine to the rear wheel. A handle bar assembly rotatably connected to the head tube for steering the vehicle.
[00021] In an embodiment, the power unit may include a starter system for cranking the vehicle. The starter includes an electric starter mechanism and a mechanical starter mechanism. The mechanical starter system is operated by a kick-start mechanism that is coupled to the crankshaft of the engine. Whereas, the electrical starter system includes a starter motor coupled to a crankshaft. An auxiliary power source, for example a battery, or a fuel cell, or the like, drives the starter motor. Further, an auxiliary storage compartment is mounted to the frame assembly and being disposed in proximity to the power unit. The auxiliary power source is mounted to said storage compartment of the frame assembly. In another embodiment, the auxiliary storage compartment is capable of accommodating an engine control unit or a vehicle control unit, which control various vehicle parameters.
[00022] In an embodiment, a battery is mounted to the frame assembly. The battery is electrically connected to the electrical starter system. The auxiliary storage compartment is disposed in proximity to the power unit. In addition, in an embodiment, the auxiliary storage compartment is mounted to the main tube at a mounting portion. At the mounting portion, the centre line of the frame assembly cuts through the longitudinal axis of the vehicle at a first angle. In other words, the center line passing through said mounting portion is inclined to a longitudinal axis of the vehicle by a first angle. Preferably, the first angle is an acute angle. Providing the auxiliary storage compartment at the mounting portion enables reduced wiring harness length for connecting the battery or the like with the power unit i.e., specifically to starter motor or a traction.
[00023] In an embodiment, the auxiliary storage compartment is disposed on the main tube towards a front portion of the vehicle. Therefore, a fuel tank disposed on to the main tube covers at least a portion of the auxiliary storage compartment, when viewed from top of the vehicle. Further, the auxiliary storage compartment is mounted to a mounting portion on the main tube by means of a mounting bracket. In an embodiment, a sheet metal mounting bracket is welded or the like to the rear tube. In one embodiment, the mounting bracket is integrally formed with the frame assembly. Further, the auxiliary storage compartment is capable of covering at least a portion of the battery. In an embodiment, a casing with a locking mechanism is provided to the auxiliary storage compartment of the vehicle. This secures the battery or the like stored in the auxiliary storage compartment from theft.
[00024] In another embodiment, the auxiliary storage compartment is mounted to a mounting portion on the rear tube that extends inclinedly rearward from the down tube. Further, the centre line of the frame assembly at the mounting portion cuts through the longitudinal axis of the vehicle at an acute angle. As, the power unit is disposed adjoiningly below the down tube, the auxiliary storage compartment is in proximity to the power unit thereby providing compact packaging at the same enabling optimum wiring. Also, in case of the vehicle with power unit including the IC engine and the electric motor, the packing space of the power unit below the down tube is not compromised. Furthermore, the auxiliary storage compartment is capable of accommodating a battery. The wiring harness required to connect the battery or the like to the power unit is reduced. Further, in an embodiment, the power unit having an IC engine includes a magneto setup that is used to charge the battery. Therefore, the auxiliary storage compartment holding the battery is in proximity to the magneto setup. Therefore, the wiring harness for connecting the magneto setup to the battery is reduced. A mounting bracket is welded or the like to the frame assembly for holding the auxiliary storage compartment. Further, the seat assembly is mounted to the rear tube and the seat assembly covers at least a portion of the auxiliary storage compartment when viewed from top of the vehicle.
[00025] In an embodiment, a casing is provided for securing the auxiliary storage compartment of the vehicle. In addition, a locking mechanism secures the battery or the like from theft. The casing is made of metal or plastic. In addition, the utility space on the vehicle is not compromised.
[00026] The aforesaid and other advantages of the present subject matter would be described in greater detail in conjunction with the figures in the following description.
[00027] 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.
[00028] Fig. 1 (a) illustrates a left side view of an exemplary two-wheeled type-through type vehicle, in accordance with an embodiment of present subject matter. Fig. 1 (b) depicts the frame assembly of the vehicle depicted in Fig. 1 (a). The vehicle 100 has a frame assembly 105, which acts as the skeleton for bearing the loads. The frame assembly is a mono-tube type frame assembly 105 that includes a head tube 105A, a main tube 105B, a down tube 105A, and a rear tube 105D. The main tube 105B extends rearwardly downward from the head tube 105A. The down tube 105C extends rearward, along a longitudinal axis of the vehicle 100, from a rear portion of the main tube 105B. The rear tube 105C extends inclinedly rearward from a rear portion of the down tube 105C towards a rear portion R of the vehicle. A centre line C-C’ extends along the frame assembly from a front portion towards a rear portion. The centre line C-C’ passes substantially along the centre of cross-section of the frame assembly 105. In other words, the center line C-C’ passes along the circumferential centre of the frame assembly 105. In a preferred embodiment, the frame assembly 105 is a tubular structure and the centre line extends along the circumferential center of the tubular structure. Therefore, the centre line C-C’ extends from the head tube 105C along the centre of cross-section of the main tube 105B, then extends along the centre of cross-section of the down tube 105C and along the center of the cross-section of the rear tube 105D. Therefore, the centre line C-C’ extends along the circumferential center of the main tube 105B, along the circumferential center of the down tube 105B, and along the circumferential center of the rear tube 105D (as depicted in Fig. 1 (b)).
[00029] A handle bar assembly 115 is pivotally disposed through the head tube 105A. The handle bar assembly 115 is connected to a front wheel 110 by one or more front suspension(s) 120. A front fonder 125 is disposed above the front wheel 110 for covering at least a portion of the front wheel 110. A fuel tank 130 is mounted to the main tube 105A of the frame assembly 105 and it is disposed in the front portion F of a step-through space of the frame assembly 105. The power unit 135 is mounted to the down tube 105C. In the present embodiment, the power unit 135 is an IC engine. Hereinafter, the terms IC engine and the power unit are interchangeably used. The power unit 135 includes an electric motor that acts as a traction motor. The fuel tank 130 is functionally connected to the power unit 135. In an embodiment, a piston axis of the engine is horizontal i.e. parallel to a longitudinal axis of the vehicle 100. A swing arm 140 is swingably connected to the frame assembly 105. A rear wheel 145 is rotatably supported by the swing arm 140. One or more rear suspension(s) 150, which are connecting the swing arm 140 at an angle, to sustain both the radial and axial forces occurring due to wheel reaction, to the frame assembly 105. A rear fender 155 is disposed above the rear wheel 145. A seat assembly 160A, 160B is disposed at a rear portion R of the step-through space. In an embodiment, the seat assembly 160 includes a rider seat 160A, and a pillion seat 160B. Further, the seat assembly 160A, 160B is positioned above the rear wheel 145.The vehicle is supported by a centre stand mounted to the frame assembly 105. A floorboard 165 is mounted above the down tube 105C. The floorboard 165 covers at least a portion of the power unit 135.
[00030] The internal combustion (IC) engine of the power unit 135 includes an, an air intake system (not shown), an exhaust system (not shown), and a starter system (not shown). The starter system includes an electric starter mechanism or a mechanical starter mechanism. The electrical starter system is powered by an auxiliary power source, for cranking the IC engine. Power generated by IC engine is transferred to the rear wheel 145 through a transmission system (not shown).
[00031] Fig. 2 (a) illustrates a left side view of a two-wheeled vehicle, in accordance with an embodiment of the present subject matter. An auxiliary storage compartment 210 is mounted to the frame assembly 105. The power unit 135 is mounted to the frame assembly 105 at a lower portion of the down tube 105C. In an embodiment, the engine assembly of the power unit 135 is forwardly inclined. The power unit 135 includes an electrical starter system that includes a starter motor. In an embodiment, the power unit may include a traction motor that is powered by the auxiliary power source. The auxiliary storage compartment 210 is capable of accommodating a battery (not shown) that is electrically connected to the starter motor. In the present embodiment, the auxiliary storage compartment 210 is covered by at least a portion of the fuel tank 130 when viewed from top. In an embodiment, the auxiliary storage compartment 210 is secured to the vehicle by means of a casing (not shown) with a locking mechanism. The auxiliary storage compartment 210 is disposed in proximity to the power unit 135. This enables reduced wiring harness required for connecting the battery that is disposed in the auxiliary storage compartment 210 to the power unit 135.
[00032] Fig. 2 (b) illustrates a left view of a frame assembly, in accordance with an embodiment of the present subject matter. The power unit 135 (shown in Fig. 2 (a)) includes the engine assembly that is mounted to the down portion of the down tube 105C. An engine-mounting bracket 170 provided on the down tube 105C secures the engine assembly to the frame assembly of the vehicle 200. The auxiliary storage compartment 210 is mounted to a mounting portion M1 on main tube 105B of the frame assembly 105 by means of a mounting bracket 205. The down tube 105C is extending inclinedly rearward from the head tube 105A. A centre line C-C’, which passes through the centre of the cross-section of the frame, at the mounting portion M1 of the frame assembly 105 cuts the longitudinal axis L-L’ of the vehicle 200 at an acute angle a. The auxiliary storage compartment 210 is disposed to the main tube 105B on a surface that is towards a front portion F of the vehicle. In an embodiment, the mounting bracket 205 is made of sheet metal and is welded or the like to the frame assembly 105. The auxiliary storage compartment 210 is capable of covering at least a portion of the battery 220. This enables in reducing wiring harness required to connect the battery or the like disposed in the storage compartment 210 to the power unit 135. In an embodiment, the battery 220 disposed in the auxiliary storage compartment 210 is covered by a casing (not shown) by having a locking mechanism. The casing covers the auxiliary storage compartment.
[00033] Further, the auxiliary storage compartment 210 is covered by at least portion of the fuel tank 130 mounted to the frame assembly 130, when viewed from a top of the vehicle 200. Furthermore, the auxiliary storage compartment 210 is disposed without comprising on the utility space of the vehicle 200.
[00034] In one embodiment, the auxiliary storage unit 410 is mounted to the frame assembly 105B to at least one of main tube and the rear tube 105D. The front wheel 110 of the vehicle 100 has a front wheel axle (not shown), which coincides with an axis of rotation of the front wheel 110. Similarly, the rear wheel 145 of the vehicle 100 has a rear wheel axle (not shown), which coincides with an axis of rotation of the rear wheel 145. The auxiliary storage unit 210 is disposed between the front wheel axle and the rear wheel axle thereby providing optimum weight distribution. Moreover, the auxiliary storage unit 210 is disposed above an imaginary plane passing through the front wheel axle and the rear wheel axle thereby providing ease of access to the storage unit 210. The imaginary plane is a horizontal plane (not shown).
[00035] Fig. 3 (a) illustrates a rear portion of the vehicle, in accordance with another embodiment of the present subject matter. The auxiliary storage compartment 310 is mounted to the rearwardly inclined portion of the rear tube 105D that extends from the rear portion of the down tube 105C towards a rear portion R of the vehicle 300. The power unit 135 is mounted to the down portion of the down tube 105C. The auxiliary storage compartment 310 is capable of accommodating at least a portion of a battery or a control unit or the like. The rider seat 155A of the seat assembly 155 covers at least a portion of the auxiliary storage compartment 310 when viewed from top view.
[00036] Further, in an embodiment, the battery 320 disposed in the auxiliary storage compartment 310 is connected to a magneto setup (not shown) of the power unit 135, including the engine assembly, by wiring harness. The present subject matter enables reducing length of wiring harness required to connect the battery 320 to the power unit 135.
[00037] Fig. 3 (b) depicts a left side view of the frame assembly of the vehicle, in accordance with an embodiment of the present subject matter. The auxiliary storage compartment 310 in this particular embodiment is mounted to the frame assembly 105 at a mounting portion M2, which is having a centre line C-C’ at said portion cutting the longitudinal axis L-L’ at an acute angle a. In addition, the power unit 135 having an engine assembly is mounted to the down tube 105C. Therefore, the auxiliary storage compartment 310 is mounted to the rear tube 105D and disposed in proximity to the power unit 135. A mounting bracket 305 is welded or the like to the rear tube 105D. The mounting bracket 305 is made of metal sheet. The auxiliary storage compartment 310 is capable of accommodating a battery or the like. In an embodiment, vehicle components including control unit or the like is secured in the auxiliary storage compartment 310.
[00038] Further, the auxiliary storage compartment 310 is mounted to a mounting portion M2 on the frame assembly 105 at which the centre line that cuts through the longitudinal axis L-L’ of the vehicle at an acute angle a. In other words, the center line C-C’ of the frame assembly 105 is passing through the mounting portion M2 is inclined to a longitudinal axis L-L’ of the vehicle by a first angle a. The acute angle is in the range of 20 degrees to 70 degrees. The auxiliary storage unit 310 is in proximity to the power unit 135 of the engine assembly. This enables, the battery secured in the auxiliary storage unit 310 to optimally connect with the power unit 135. Thus, the length of wiring harness is reduced thereby the cost is reduced.
[00039] Fig. 3 (c) depicts a left side perspective of the rear portion of the vehicle depicted in Fig. 3 (a). In Fig. 3 (c), the auxiliary storage compartment 310 is depicted in an exploded view. The auxiliary storage compartment 310 is capable of accommodating a battery 320 and covers at least a portion of the battery 320. In an embodiment, a band 315 secures the battery 320 in the auxiliary storage compartment. In an embodiment, the auxiliary storage compartment 310 is secured in a casing 325, 330. Furthermore, a locking mechanism 335 is also provided. This secures the battery 320 or the like, stored in the auxiliary storage compartment 310 from theft. The seat assembly 160 (shown in Fig. 3 (a)) is disposed at the rear portion of the step-through space and the seat assembly 155 is mounted to at least one seat mounting bracket 175.When viewed from top portion, the seat assembly covers at least a portion of the auxiliary storage compartment 310. The casing 325, 330 prevents the battery 320 from getting damaged due to exposure to atmosphere. Rainwater or dirt is also prevented from entering the auxiliary storage compartment 310. Furthermore, the present subject matter enables accommodation of the battery 320 in the compactly packaged vehicle, without compromising on the utility space. Furthermore, accessing of the battery or the like, from auxiliary storage compartment 310, during servicing, is easy.
[00040] Fig. 4 depicts a top perspective view of the vehicle, in accordance with yet another embodiment of the present subject matter. An auxiliary storage compartment 410 is mounted to the frame assembly 105 at a mounting portion M2, which is having a centre line C-C’, which passes through the centre of cross-section of the frame structure along the frame assembly, at said portion cutting the longitudinal axis L-L’ at an acute angle a. Also, the power unit 135 (not shown) is mounted to the down tube 105C. Further, a bottom portion of the auxiliary storage compartment 410 is provided a tool box 410T that is disposed in the bottom portion of the auxiliary storage compartment 410. In addition, the storage compartment 410 is adapted to accommodate an auxiliary storage unit 420 such as battery or the like. Also, the storage compartment 410 is provides with an electronic control unit 440. In a preferred embodiment, the battery 420 is disposed towards one lateral side in the storage compartment 410 and the control unit 440 disposed on other lateral side of the storage compartment 410. This enables in balancing the centre of gravity (CG) of the vehicle, as the offset in CG is compensated by the battery position 420. Therefore, the CG is brought substantially to the lateral centre of the vehicle 400, whereby ridability is improved.
[00041] Further, the rider seat 155A is hingedly above the auxiliary storage compartment 410. This enables ease of access to the battery 420 and the control unit 440 for maintenance. The rider seat 155A is secured above the auxiliary storage compartment by a lock assembly (not shown). Further, the tool box 410T is provided with a lid being disposed in the front portion of the storage compartment 410. In one embodiment, the tool box 410T is integrally formed with the auxiliary storage compartment 410.
[00042] 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 two-wheeled vehicle (200, 300, 400) including one or more electrical components (220, 320, 420, 440) optimally disposed in proximity to a power unit (135), said two-wheeled vehicle (200, 300, 400) comprising:
a frame assembly (105) comprising a head tube (105A), a main tube (105B) extending rearwardly downward from the head tube (105A), a down tube (105C) extending rearward from a rear end of the main tube (105B), and a rear tube (105D) extending inclinedly rearward from a rear end of the down tube (105C), and said frame assembly (105) has a centre line (C-C’) passing substantially along said frame assembly (105); and
said power unit (135) disposed adjoiningly below said down tube (105C),
wherein
an auxiliary storage compartment (210, 310, 410) capable of accommodating said one or more electrical components (220, 320, 420, 440) is mounted to a mounting portion (M1, M2) of said frame assembly (105), wherein said center line (C-C’) of said frame assembly (105) passing through said mounting portion (M1, M2) is inclined to a longitudinal axis (L-L’) of the vehicle (200, 300) by a first angle (a).
2. The two-wheeled vehicle (200, 300, 400) of claim 1, wherein said auxiliary storage compartment (210, 310, 410) is capable of accommodating said one or more electrical components including a battery (220, 320, 410) and an electronic control unit (440).
3. The two-wheeled vehicle (200, 300, 400) of claim 1 further comprises a power unit (135) disposed adjoiningly below said down tube (105C), and said power unit (135) includes at least one of an internal combustion engine (135) and an electrical motor.
4. The two-wheeled vehicle (200, 300, 400) of claim 1 or 3, wherein said power unit (135) including said internal combustion engine (135) is having at least one of a magneto or an integrated starter generator functionally connected to said one or more electrical components (220, 320, 420, 440).
5. The two-wheeled vehicle (200, 300, 400) of claim 1, wherein said auxiliary storage compartment (210, 310, 410) is mounted at said mounting portion (M1, M2) of the frame assembly (105) through a mounting bracket (205, 305) affixed to said frame assembly (105).
6. The two-wheeled vehicle (200) of claim 1, wherein said auxiliary storage compartment (210) is mounted to a front facing side of said main tube (105B), and at least a portion said auxiliary storage compartment (210) is enclosed by a fuel tank (130) mounted to said main tube (105B).
7. The two-wheeled vehicle (300, 400) of claim 1,wherein said auxiliary storage compartment (310, 410) is mounted to a front facing side of said rear tube (105D), and at least a portion said auxiliary storage compartment (310, 410) overlaps with a seat assembly mounted to said rear tube (105D), when viewed from vehicle top.
8. The two-wheeled vehicle (400) of claim 1, wherein said auxiliary storage unit (410) is capable of accommodating a battery (420) mounted towards one lateral side of the vehicle (100) and an electronic control unit (440) disposed towards other lateral side of the vehicle (100).
9. The -wheeled vehicle (200, 300) of claim 1, wherein said first angle (a) is an acute angle in a range of 20-70 degrees.
10. The two-wheeled vehicle (300) of claim 1,wherein said auxiliary storage compartment (210, 310, 410) is mounted to the frame assembly (105), and said auxiliary storage compartment (210, 310, 410) is disposed between front wheel axle and a rear wheel axle and substantially above an imaginary plane passing through said front wheel axle and said rear wheel axle.