A Wheel Structure for a Saddle Type Vehicle

FIELD OF THE INVENTION

[001] The present invention relates to a wheel structure for a saddle type vehicle.

BACKGROUND OF THE INVENTION

[002] In conventional saddle type vehicles, a wheel comprises a hub part, spoke or arm parts extending from the hub to the outer side of the wheel. The outer side of the wheel is generally referred to as a rim part and the rim part is connected radially to all the arms/ spokes terminating at the rim. With the evolving vehicle norms and performance requirements, the need for improved vehicle performance parameters is increasing. One of the major parameters in vehicle performance is moving parts and the associated weight of the moving parts. One of the prime moving parts of the vehicle is the wheel. Wheel weight is a major contributor to the overall vehicle weight, thereby having a major role to play in overall performance and fuel economy of the vehicle.

[003] As wheel is one of the most important moving parts of the vehicle, the demand for wheels with higher performance characteristics, higher strength, having a higher life span, while having lower weight is ever increasing. The wheels conventionally use a wheel rim that has an administering surface to receive a tire. The wheel rim is then welded to the spokes in a fixed manner The spokes may then further be connected to a brake disc having a radial plate structure. In addition to the direct dissipation of heat from the brake disc to the atmosphere, a part of the heat is transferred to the wheels, which is then dissipated from the wheels, and thus wheels need to have sufficient heat dissipation.

[004] Conventional wheels are generally welded or integrally casted and have certain limitations such as poor dissipation of the heat transferred from the brake disc, lower structural strength and short life as they are susceptible to impact damage.

[005] Thus, there is a need in the art for a wheel structure for a saddle type vehicle which addresses the aforementioned problems.

SUMMARY OF THE INVENTION

[006] In an aspect, the present invention is directed towards a wheel structure for a saddle type vehicle. The wheel structure has a hub portion supported on an axle of the saddle type vehicle, a rim portion for supporting a tire which is provided radially outwardly from the hub portion, and a plurality of arms extending between the hub portion and the rim portion. Herein, each of the arms have a pair of spokes such that the distance between the pair of spokes gradually increases from the hub portion to a first radially outward end, and gradually decreases from the first radially outward end to the rim portion.

[007] In an embodiment of the invention, the pair of spokes of each of the arms form a closed loop structure between the hub portion and the rim portion.

[008] In a further embodiment of the invention, the pair of spokes of each of the arms form a substantially heptagonal closed loop structure between the hub portion and the rim portion, in a vehicle side view.

[009] In a further embodiment of the invention, length of one of the spokes in pair of spokes is greater than length of the other spoke in the pair of spokes. [010] In another embodiment of the invention, each of the arms has a first connecting portion for connecting each of the arms to the hub portion, such that the gap between the pair of spokes is a first length at the first connecting portion.

[011] In a further embodiment of the invention, each of the arms has a second connecting portion for connecting each of the arms to the rim portion, such that the gap between the pair of spokes is a second length at the second connecting portion.

[012] In another embodiment of the invention, the second length is greater than the first length.

[013] In another embodiment of the invention, the hub portion has a cavity wall and a raised portion configured to receive each of the arms.

[014] In a further embodiment of the invention, each of the spokes have an outer surface and an inner surface, such that the spokes curve away from a wheel centreline extending in an up-down direction, in a wheel rear view.

[015] In another embodiment of the invention, the outer surface of the spoke is received at the cavity wall of the hub portion, and the inner surface of the spoke is received at the raised portion of the hub portion.

[016] In another embodiment of the invention, a gap between the cavity wall and the raised portion of the hub portion, is greater than a gap between the inner surface and the outer surface of the spokes at the rim portion, in the wheel rear view.

BRIEF DESCRIPTION OF THE DRAWINGS

[017] Reference will be made to embodiments of the invention, examples of which may be illustrated in accompanying figures. These figures are intended to be illustrative, not limiting. Although the invention is generally described in context of these embodiments, it should be understood that it is not intended to limit the scope of the invention to these particular embodiments.

Figure 1 illustrates a left side view of an exemplary saddle type vehicle, in accordance with an embodiment of the invention.

Figure 2 illustrates a right view of a wheel structure for the saddle type vehicle, in accordance with an embodiment of the invention.

Figure 3 illustrates a perspective view of the wheel structure, in accordance with an embodiment of the invention.

Figure 4 illustrates a rear sectional view of the wheel structure, in accordance with an embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

[018] The present invention relates to a wheel structure for a saddle type vehicle.

[019] Figure 1 illustrates a left-side view of an exemplary saddle type vehicle 10, in accordance with an embodiment of the present subject matter. The vehicle 10 comprises a frame. The frame comprises a head pipe (not shown), and a main frame (not shown), which extends rearwardly and downwardly from the head pipe to a floorboard 18. One or more front suspensions 44 connect a front wheel 14 to a handlebar 20, which forms a steering assembly of the vehicle 10. The steering assembly is rotatably disposed about the head pipe. The main frame further includes a portion extending horizontally and rearwardly in a vehicle front rear direction. Further, the frame includes a left side frame (not shown) and a right side frame (not shown) extending inclinedly rearward towards a rear portion of the vehicle 10.

[020] The vehicle 10 includes a power unit 12 that comprises at least an internal combustion (IC) engine or an electric drive source. The power unit 12 is coupled to a rear wheel 16. In one embodiment, the engine or the electric drive source is swingably connected to the frame. In one embodiment, the engine or the electric drive source is mounted to a swing arm (not shown) and the swing arm is swingably connected to the frame. Further, the vehicle 10 includes a transmission means (not shown) coupling the rear wheel 16 to the power unit 12. The transmission means includes a continuously variable transmission, an automatic transmission, or a fixed ratio transmission. A seat assembly 22 is disposed above the power unit 12 and is supported by the left side frame and the right side frame. The seat assembly 22 is hingedly openable. The frame defines a step-through portion ahead of the seat assembly 22. The floorboard 18 is disposed at the step-through portion, wherein a rider can operate the vehicle 10 in a seated position by resting feet on the floorboard 18. Further, the floorboard 18 is capable of carrying loads.

[021] Further, the frame is covered by plurality of body panels including a front panel 30 having a front face 30A and a rear face 30B, an under-seat cover 32, and a left and a right- side panel 33 disposed on the frame and covering the frame and parts mounted thereof.

[022] In addition, a front fender 28 is covering at least a portion of the front wheel 14. A utility box (not shown) is disposed below the seat assembly 22 and is supported by the frame. A rear fender 26 is covering at least a portion of the rear wheel 16 and is positioned upwardly of the rear wheel 16. One or more suspension(s) 46 are provided in the rear portion of the vehicle 10 for connecting the swing arm and the rear wheel 16 to the frame for damping the forces from the rear wheel 16 and the engine from reaching the frame.

[023] Furthermore, the vehicle 10 comprises of plurality of electrical and electronic components including a headlight 36, a taillight 38, an alternator (not shown), and a starter motor (not shown). [024] Figure 2 illustrates a wheel structure 100 for the saddle type vehicle 10. As illustrated in the Figure, the wheel structure 100 comprises of a hub portion 110 that is supported on an axle (not shown) of the saddle type vehicle 10. The hub portion 110 of the wheel structure 100 is supported on either a front axle or a rear axle of the vehicle 10 as required. The wheel structure 100 further comprises a rim portion 120 for supporting a tire. Herein, the rim portion 120 is provided radially outwardly from the hub portion 110. The wheel structure 100 further has a plurality of arms 130 that extend between the hub portion 110 and the rim portion 120. [025] As further illustrated in Figure 2, each of the arms 130 have a pair of spokes 140. The pair of spokes 140 are provided such that the distance between the pair of spokes 140 gradually increases from the hub portion 110 to a first radially outward end 142, and gradually decreases from the first radially outward end 142 to the rim portion 120. As a result of such a disposition of the pair of spokes 140, in an embodiment, the pair of spokes 140 of each of the arms 130 form a closed loop structure between the hub portion 110 and the rim portion 120. In an embodiment, the number of arms 130 extending between the hub portion 110 and the rim portion 120 is five, thereby forming five closed loop structures.

[026] In the embodiment illustrated in Figure 2, the pair of spokes 140 of each of the arms 130 form a substantially heptagonal closed loop structure between the hub portion 110 and the rim portion 120, in a vehicle side view. The heptagonal closed loop structure allows for efficient distribution of operating load and impact load on the wheel structure 100, thereby providing structural strength to the wheel structure 100.

[027] As illustrated in Figure 3 and referenced in Figure 2, in an embodiment, length of one of the spokes in pair of spokes 140 is greater than length of the other spoke in the pair of spokes 140. The heptagonal closed loop structure thereby formed provides greater structural strength to the wheel structure 100. [028] As further illustrated in Figure 3, in an embodiment, each of the arms 130 comprise a first connecting portion 132 for connecting each of the arms 130 to the hub portion 110, such that the gap between the pair of spokes 140 is a first length L1 at the first connecting portion 132. Further, each of the arms 130 comprise a second connecting portion 134 for connecting each of the arms 130 to the rim portion 120, such that the gap between the pair of spokes 140 is a second length L2 at the second connecting portion 134. To further improve the structural strength of the wheel structure 100, in this embodiment, the second length L2 is greater than the first length L1 .

[029] Figure 4 illustrates a rear sectional view of the wheel structure 100 in accordance with an embodiment of the invention. As illustrated in Figure 4, the hub portion 110 comprises of a cavity wall 112 and a raised portion 114 configured to receive each of the arms 130. Each of the arms 130, thus extend between the cavity wall 112 and the raised portion 114 on the hub portion 110, to the rim portion 120. The provision of the raised portion 114 on the hub portion 110 ensures that the load distribution from the arms 130 to the hub portion 110 occurs in a gradual manner and there are no fracture points where the arms 130 are attached with the hub portion 110.

[030] As further illustrated in Figure 4, each of the spokes 140 have an outer surface 144 and an inner surface 146. The inner surface 146 and the outer surface 144 of the spokes 140 are provided such that the spokes 140 curve away from a wheel centreline (X-X’) extending in an up-down direction, in a wheel rear view. In that, when the wheels are attached on the saddle type vehicle 10, from a vehicle rear view, the spokes 140 curve towards the right of the wheel centreline (X-X’). The inner surface 146 slightly curves towards the wheel centreline (X-X’) before terminating at the hub portion 110. Provision of such curvature allows a higher length of the spokes 140, and hence better load distribution. [031] As illustrated in Figure 4, the outer surface 144 of the spoke 140 is received at the cavity wall 112 of the hub portion 110, and the inner surface 146 of the spoke 140 is received at the raised portion 114 of the hub portion 110.

[032] In the embodiment illustrated in Figure 4, a gap T1 between the cavity wall 112 and the raised portion 114 of the hub portion 110, is greater than a gap T2 between the inner surface 146 and the outer surface 144 of the spokes 140 at the rim portion 120, in the wheel rear view. As an effect, the thickness of the spokes 140 in the wheel rear view varies from the rim portion 120 to the hub portion 110 and is maximum at the hub portion 110.

[033] Such a configuration allows for a greater surface area at the position where the spokes 140 are in contact with the hub portion 110, which not only improves structural strength as the load on the hub portion 110 is reduced, but also allows for greater heat transfer between the hub portion 110 and the spokes 130, thereby providing better heat dissipation characteristics.

[034] Advantageously, the present invention provides for a wheel structure which has a high structural strength. The closed loop structure allows for a high structural strength as the weight is uniformly distributed throughout the wheel structure, without usage of high masses of material, thereby keeping the weight of the wheel low. A lower weight of the wheel, without compromising on the strength of the wheel, results in better vehicle performance and improved fuel economy.

[035] Further, the wheel structure of the present invention achieves higher heat dissipation, better strength against impact damage, uniform load distribution along the wheel structure, meaning that no particular wheel structure part is overly stressed, thus prolonging the life of the wheel. [036] While the present invention has been described with respect to certain embodiments, it will be apparent to those skilled in the art that various changes and modification may be made without departing from the scope of the invention as defined in the following claims.