Claims:WE CLAIM:
1. A mounting shaft (100a, 100b) for a frame structure (202) of a vehicle (200), the mounting shaft (100a, 100b) comprising:
a body member (102) adapted to be mounted onto the frame structure (202), the body member (102) comprising:
a first tubular insert (104) extending from a first end (106) of the body member (102), the first tubular insert (104) adapted to receive a first tube (204) of the frame structure (202); and
a second tubular insert (108) extending from a second end (110) of the body member (102), the second tubular insert (108) adapted to receive a second tube (206) of the frame structure (202).

2. The mounting shaft (100a, 100b) as claimed in claim 1, wherein the first tubular insert (104) is adapted to receive the first tube (204), the first tube (204) being an upper tube (204a) of the frame structure (202).

3. The mounting shaft (100a, 100b) as claimed in claim 1, wherein the second tubular insert (108) is adapted to receive the second tube (206), the second tube (206) being a side tube (206a) of the frame structure (202).

4. The mounting shaft (100a, 100b) as claimed in claim 1 comprises a third tubular insert (112) extending from a third end (114) of the body member (102), wherein the third tubular insert (112) is adapted to receive one of a rear tube (208a) of the frame structure (202) or a rear fender (208b) of the vehicle (200).

5. The mounting shaft (100a, 100b) as claimed in claim 1 comprises one or more mounting bosses (116) defined on the body member (102).

6. The mounting shaft (100a, 100b) as claimed in claim 5, wherein the one or more mounting bosses (116) comprise a first mounting boss (116a) adapted to receive and support an end of a rear shock absorber of the vehicle (200).

7. The mounting shaft (100a, 100b) as claimed in claim 5, wherein the one or more mounting bosses (116) comprise at least one of:
a second mounting boss (116b) adapted to receive and support an engine mount of the vehicle (200);
a third mounting boss (116c) adapted to receive and support a footrest (210) of the vehicle (200); and
a fourth mounting boss (116d) adapted to receive and support a center stand (212) of the vehicle (200).

8. The mounting shaft (100a, 100b) as claimed in claim 1, wherein the first tubular insert (104) is adapted to receive the first tube (204), the first tube (204) being a centre tube (204b) of the frame structure (202).

9. The mounting shaft (100a, 100b) as claimed in claim 1 is manufactured by forging.

10. A frame structure (202) for a two-wheeled vehicle (200), the frame structure (202) comprising:
a head pipe (214);
a downtube (216) extending downwardly from the head pipe (214);
a main frame member (218) extending rearwardly from the head pipe (214); and
a mounting shaft (100a, 100b) mounted onto the main frame member (218), the mounting shaft (100a, 100b) comprising:
a body member (102) comprising:
a first tubular insert (104) extending from a first end (106) of the body member (102), the first tubular insert (104) adapted to receive a first tube (204) of the frame structure (202); and
a second tubular insert (108) extending from a second end (110) of the body member (102), the second tubular insert (108) adapted to receive a second tube (206) of the frame structure (202).
11. The frame structure (202) as claimed in claim 10, wherein the first tubular insert (104) is adapted to receive the first tube (204), the first tube (204) being an upper tube (204a) of the frame structure (202).

12. The frame structure (202) as claimed in claim 10, wherein the second tubular insert (108) is adapted to receive the second tube (206), the second tube (206) being a side tube (206a) of the frame structure.

13. The frame structure (202) as claimed in claim 10 comprises a third tubular insert (112) extending from a third end (114) of the body member (102), wherein the third tubular insert (112) is adapted to receive one of a rear tube (208a) of the frame structure (202) or a rear fender (208b) of the vehicle (200).

14. The frame structure (202) as claimed in claim 10 comprises one or more mounting bosses (116) defined on the body member (102).

15. The frame structure (202) as claimed in claim 15, wherein the one or more mounting bosses (116) comprise a first mounting boss (116a) adapted to receive and support an end of a rear shock absorber of the vehicle (200).

16. The frame structure (202) as claimed in claim 14, wherein the one or more mounting bosses (116) comprise at least one of:
a second mounting boss (116b) adapted to receive and support an engine mount of the vehicle (200);
a third mounting boss (116c) adapted to receive and support a footrest (210) of the vehicle (200); and
a fourth mounting boss (116d) adapted to receive and support a center stand (212) of the vehicle (200).

17. The frame structure (202) as claimed in claim 10, wherein the first tubular insert (104) is adapted to receive the first tube (204), the first tube (204) being a centre tube (204b) of the frame structure (202).
, Description:FIELD OF THE INVENTION
[001] The present invention relates to a frame structure for a vehicle, more particularly relates to a mounting shaft for the frame structure.

BACKGROUND OF THE INVENTION
[002] Vehicles, such as two-wheeled vehicles, include a frame structure for supporting its components thereon. Typically, the frame structure includes an upper tube, a central tube, a down tube and a side tube connected suitably by a series of welding joints to form a load-bearing structure. Additionally, components such as, rear dual suspension are mounted on a left and right side at rear portion of the frame structure. The dual suspension is mounted onto the rear portion via a mounting boss and thereafter shafts of the dual suspension are welded to a frame gusset that forms a bridge and connects upper and side tubes of the frame structure.
[003] However, welding carried out while connecting the tubes of the frame structure and/or for mounting the dual suspension to the rear portion of the frame structure includes a series of welding operations one after another, resulting in multiple welding zones in the frame structure. The welded zones get heat affected resulting in material distortion. Apart from the material distortion, the heat accumulation also weakens the frame gusset and leading to a notch effect of the mounting boss. Furthermore, overlapping regions are formed due to multiple butt-joints or lap joints between tubes create peak stress zones similar to the notch effect, leading to cracking of the frame structure. Further, there are chances of poor welding quality and joining practices during construction of the frame structure, resulting in decreased strength in the frame structure, which is undesirable.
[004] In view of the above, there is a need for a mounting shaft for the frame structure, which addresses one or more limitations stated above.

SUMMARY OF THE INVENTION
[005] In one aspect, a mounting shaft for a frame structure of a vehicle is disclosed. The mounting shaft includes a body member adapted to be mounted onto the frame structure. The body member includes a first tubular insert extending from a first end of the body member and is adapted to receive a first tube of the frame structure. A second tubular insert extends from a second end of the body member and is adapted to receive a second tube of the frame structure.
[006] In an embodiment, the first tubular insert is adapted to receive the first tube, wherein the first tube being an upper tube of the frame structure.
[007] In an embodiment, the second tubular insert is adapted to receive the second tube, wherein the second tube is a side tube of the frame structure.
[008] In an embodiment, a third tubular insert extends from a third end of the body member, wherein the third tubular insert is adapted to receive one of a rear tube of the frame structure or a rear fender of the vehicle.
[009] In an embodiment, one or more mounting bosses are defined on the body member.
[010] In an embodiment, the one or more mounting bosses include a first mounting boss adapted to receive and support an end of a rear shock absorber of the vehicle.
[011] In an embodiment, the one or more mounting bosses include at least one of a second mounting boss adapted to receive and support an engine mount of the vehicle, a third mounting boss adapted to receive and support a footrest of the vehicle and a fourth mounting boss adapted to receive and support a center stand of the vehicle.
[012] In an embodiment, wherein the first tubular insert is adapted to receive the first tube. The first tube is a centre tube of the frame structure.
[013] In an embodiment, wherein mounting shaft is manufactured by forging.
[014] In another aspect, a frame structure for a two-wheeled vehicle is disclosed. The frame structure includes a head pipe, a downtube extending downwardly from the head pipe and a main frame member extending rearwardly from the head pipe. A mounting shaft is mounted onto the main frame member. The mounting shaft includes a body member including a first tubular insert extending from a first end of the body member. The first tubular insert is adapted to receive a first tube of the frame structure and a second tubular insert extending from a second end of the body member. The second tubular insert is adapted to receive a second tube of the frame structure.
BRIEF DESCRIPTION OF THE DRAWINGS
[015] 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 is a schematic view of a vehicle, in accordance with an embodiment of the present invention.
Figure 2 is a left-side view of a frame structure of the vehicle, in accordance with an embodiment of the present invention.
Figure 3 is a perspective view of the frame structure, in accordance with an embodiment of the present invention.
Figure 4 is a rear view of the frame structure, in accordance with an embodiment of the present invention.
Figure 5 is a perspective view of a mounting shaft of the frame structure, in accordance with an embodiment of the present invention.
Figure 6a is a left-side view of the mounting shaft, in accordance with an embodiment of the present invention.
Figure 6b is a right-side view of the mounting shaft, in accordance with an embodiment of the present invention.
Figure 7 is a right-side view of the frame structure including a rear tube in accordance with an embodiment of the present invention.
Figure 8 is a top view of the frame structure including the rear tube, in accordance with an embodiment of the present invention.
Figure 9 is a schematic view of the mounting shaft, in accordance with another embodiment of the present invention.
Figure 10a is a front perspective view of the mounting shaft, in accordance with an embodiment of the present invention.
Figure 10b is a rear perspective view of the mounting shaft, in accordance with an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION
[016] Various features and embodiments of the present invention here will be discernible from the following further description thereof, set out hereunder.
[017] Figure 1 illustrates a schematic view of a vehicle 200, in accordance with an embodiment of the present invention. As an example, the vehicle 200 is a two-wheeled vehicle. The vehicle 200 comprises a prime mover 220 that is adapted to provide motive force for movement of the vehicle 200. In an embodiment, the prime mover 220 is an internal combustion engine, which is ppreferably a single-cylinder engine. The vehicle 200 comprises a front wheel 224, a rear wheel 226, a frame structure 202 (shown in Figure 2), a seat 228 and a fuel tank 230. The frame structure 202 includes a head pipe 214, a main frame member 218, a down tube 216, and an upper tube 204a (shown in Figure 3). The head pipe 214 supports a steering shaft (not shown) and a suspension assembly 232 attached to the steering shaft through a lower bracket (not shown). The suspension assembly 232 supports the front wheel 224, and is adapted to dampen the vibrations generated during vehicle movement.
[018] Further, the upper portion of the front wheel 224 is covered by a front fender 234 mounted to the lower portion of front suspension assembly 232 at the end of the steering shaft. A handlebar 236 is fixed to upper bracket (not shown) and can rotate about the steering shaft for turning the vehicle. A headlight 238, a visor guard (not shown) and instrument cluster 240 is arranged on an upper portion of the head pipe 214.
[019] Further in the present embodiment, the frame structure 202 includes a first tube 204 and a second tube 206. In an embodiment, the first tube 204 is the upper tube 204a extending from the main frame member 218 towards a rear portion of the vehicle 200. The upper tube 204a is configured to support the seat 228, and thus act as a seat rail. In another embodiment, the first tube 204 is a center tube 204b extending from the main frame member 218 towards a bottom portion of the vehicle 200. In an embodiment, the second tube 206 is a side tube 206a of the vehicle 200. Additionally, the down tube 216 may be positioned in front of the prime mover 220 and extends slantingly downward from head pipe 214.
[020] In an embodiment, as shown in Figure 4 the upper tube 204a, the center tube 204b and the side tube 206a extend from right and left sides of the vehicle 200, as per design and strength requirement of the vehicle 200. Hence, for the sake of readability and simplicity in understanding the present disclosure, a singular reference is made for each of the upper tube 204a, the center tube 204b and the side tube 206a of the frame structure 202. Thus, it is inherent that singular reference interchangeably refers to single tube or two tubes in each of the upper tube 204a, the center tube 204b and the side tube 206a.
[021] Additionally, the fuel tank 230 is mounted on the main frame member 218. The upper tube 204a are joined to main frame member 218 and extend rearward to support the seat 228. A rear swing arm 242 is connected to the frame structure 202 to swing vertically, and the rear wheel 226 is connected to rear end of the rear swing arm 242. Generally, the rear swing arm 242 is supported by a mono rear suspension 244 (as illustrated in the present embodiment) or through two suspensions on either side of the vehicle 200. A taillight unit 246 is disposed at the end of the vehicle 200 and at the rear of the seat 228. A pillion handle 248 is also provided to the upper tube 204a. The rear wheel 226 arranged below the seat 228 rotates by the motive force of the prime mover 220 transmitted through a chain drive (not shown).
[022] Further, a rear fender 250 is disposed above the rear wheel 226. An exhaust pipe 252 of the vehicle 200 extends vertically downward from the prime mover 220 and then extends below the prime mover 220, longitudinally along length of the vehicle 200 before terminating in a muffler (not shown). The muffler is typically disposed adjoining the rear wheel 226.
[023] Furthermore, the frame structure 202 further includes mounting shafts 100a, 100b. In an embodiment, the mounting shaft 100a is provided for connecting the upper tube 204a and the side tube 206a at a top portion of the frame structure 202. While the mounting shaft 100b is provided for connecting the center tube 204b and the side tube 206a at a bottom portion of the frame structure 202. The mounting shaft 100a, 100b prevents weld burns or weld distortions, thereby providing a common mounting shaft for the frame structure 202. The description pertaining to mounting shafts 100a, 100b is provided vide Figures 5-10b.
[024] Figure 5 illustrates the mounting shaft 100a in accordance with an embodiment of the present disclosure. The mounting shaft 100a is adapted to be mounted at the top potion of the frame structure 202. The mounting shaft 100a includes a body member 102 adapted to be mounted onto the frame structure 202.
[025] The body member 102 includes a first tubular insert 104 extending from a first end 106 of the body member 102. The first tubular insert 104 is adapted to receive the first tube 204 of the frame structure 202. For the mounting shaft 100a, the first tube 204 is the upper tube 204a of the frame structure 202. Also in the present embodiment the first tubular insert 104 extends along the same plane as that of the first end 106. Alternatively, the first tubular insert 104 extends angularly from the first end 106, as per design feasibility and requirement of the frame structure 202. In an embodiment, the first tube 204 is slitted and inserted onto the first tubular insert 104. The slits (not shown in Figures) on the first tube 204 are then welded, optionally seam welded, for connecting with the mounting shaft 100a.
[026] The body member 102 also includes a second tubular insert 108 extending from a second end 110 of the body member 102. The second tubular insert 108 is adapted to receive the second tube 206 of the frame structure 202. In an embodiment, the second end 110 is defined below the first end 106, for facilitating mounting of the second tube 206. Further in the present embodiment, the second tubular insert 108 extends along the same plane as that of the second end 110. Alternatively, the second tubular insert 108 extends angularly from the second end 110, as per design feasibility and requirement of the frame structure 202. In an embodiment, the second tube 206 is slitted and inserted onto the second tubular insert 108. The slits (not shown in Figures) on the second tube 206 are then welded, optionally seam welded, for connecting with the mounting shaft 100a.
[027] Further, the body member 102 of the mounting shaft 100a also includes a third tubular insert 112 extending from a third end 114. In an embodiment, the third end 114 is adapted to extend in a direction opposite to that of the first end 106 and the second end 110. Further, the third tubular insert 112 is adapted to receive one of a rear tube 208a (as shown in Figure 7) or a rear fender 208b (as shown in Figure 1) of the vehicle 200. In an embodiment, the third tubular insert 112 extends along the same plane as that of the third end 114. Alternatively, the third tubular insert 112 extends angularly from the third end 114 as per design feasibility of the rear tube 208a (as shown in Figure 7). In the present embodiment, the third tubular insert 112 extends along the same plane as that of the upper tube 204a, so that the rear tube 208a (as shown in Figure 7) is in level configuration with the upper tube 204a. Similar to the first tube 204 and the second tube 206, the rear tube 208a also includes slits which is inserted in the third tubular insert 112. The slits (not shown in Figures) on the rear tube 208a are thereafter welded, optionally seam welded, for connecting with the mounting shaft 100a.
[028] In an embodiment as shown in Figure 8, two mounting shafts 100a are provided at top portion of the frame structure 202 for connecting with the tubes 204, 206, 208a extending on the right and left side of the vehicle 200.
[029] In an embodiment, each of the first tubular insert 104, the second tubular insert 108 and the third tubular insert 112 are one of a protrusion or a projection defined on their respective ends for receiving the corresponding tubes of the frame structure 202. In the present embodiment, the first tubular insert 104, the second tubular insert 108 and the third tubular insert 112 are protrusions extending from their respective ends and are adapted to receive projections defined on the tubes of the frame structure 202.
[030] In an embodiment, the body member 102 is one of a hollow structure or a solid structure, capable of connecting the tubes 204, 206, 208a while also providing sufficient structural rigidity to the frame structure 202.
[031] In another embodiment, the dimensions of the first tubular insert 104, the second tubular insert 108 and the third tubular insert 112 are selected to facilitate mounting of the tubes 204, 206, 208a, while also providing sufficient structural rigidity to the frame structure 202.
[032] Additionally, the body member 102 includes one or more mounting bosses 116 (as shown in Figure 5). In the present embodiment, the one or more mounting boss 116 includes a first mounting boss 116a adapted to receive and support an end of a rear shock absorber of the vehicle 200. Thus, the mounting shaft 100a acts as a modular member for facilitating connection between the tubes 204, 206, 208a of the frame structure 202, while also supporting the rear shock absorber or rear suspension of the vehicle 200. Such a construction of the mounting shaft 100a eliminates separate welding operation of the gusset and the first mounting boss 116a, as required in the conventional frame structures, thereby improving strength of the frame structure 202.
[033] In an embodiment, the first mounting boss 116a is a pin member extending from an outer surface of the body member 102, as per design feasibility and requirement. The pin member is adapted to engage with an eyelet (not shown) provided on the rear shock absorber for facilitating mounting. In the present embodiment, the first mounting boss 116a extends from a left side surface of the body member 102. In another embodiment, the first mounting boss 116a extends from a right-side surface of the body member 102. In another embodiment, the dimensions of the first mounting boss 116a is selected as per the support required to be provided for the rear shock absorber.
[034] Figure 9-10b depict the mounting shaft 100b mounted at the bottom portion of the frame structure 202. As already mentioned, the mounting shaft 100b is adapted to connect the center tube 204b and the side tube 206a of the frame structure 202.
[035] Similar to the mounting shaft 100a, the mounting shaft 100b includes the body member 102 including the first tubular insert 104 and the second tubular insert 108. The first tubular insert 104 is adapted to receive the center tube 204b, while the second tubular insert 108 is adapted to receive a bottom end of the side tube 206a (for e.g. as shown in Figure 2). In the present embodiment, the first tubular insert 104 and the second tubular insert 108 is positioned adjacent to one another. The center tube 204b and the side tube 206a also include slits (not shown) for engagement with the first tubular insert 104 and the second tubular insert 108 respectively. The slits are thereafter welded, optionally seam welded, for mounting the center tube 204b and the side tube 206a onto the mounting shaft 100b.
[036] Further, the mounting shaft 100b includes the one or more mounting boss 116. The one or more mounting boss 116 includes a second mounting boss 116b, a third mounting boss 116c and the fourth mounting boss 116d. The second mounting boss 116b is adapted to receive and support an engine mount of the vehicle 200, while the third mounting boss 116c is adapted to receive and support a footrest 210 of the vehicle 200. Additionally, the fourth mounting boss 116d is adapted to receive and support a center stand 212 of the vehicle 200. In an embodiment, the engine mount, the footrest 210 and the center stand 212 are mounted onto the mounting shaft 100b via conventional mounting techniques such as fastening, clamping and the like. As such, the mounting shaft 100b facilitates mounting of multiple components, without the need for welding operation.
[037] In an embodiment, the second mounting boss 116b is located adjacent to the first tubular insert 104 (as shown in Figure 9), for facilitating mounting of the engine mount. Alternatively, location of the second mounting boss 116b is selected as per design feasibility and requirement.
[038] In an embodiment, the third mounting boss 116c is located away from the ends 106, 110 (as shown in Figure 9), for facilitating mounting of the footrest 210. Alternatively, the location of the third mounting boss 116c is selected as per design feasibility and requirement.
[039] In an embodiment, the fourth mounting boss 116d is positioned adjacent to the third mounting boss 116c (as shown in Figure 9), for facilitating mounting of the center stand 212. Alternatively, the location of the fourth mounting boss 116d is selected as per design feasibility and requirement.
[040] In the present embodiment, for the mounting shaft 100, the first end 106 is the end extending towards the upper tube 204a, the second end 110 is the end extending towards the side tube 206a and the third end 114 is the extending away from the upper tube 204a.
[041] In an embodiment as shown in Figure 8, two mounting shafts 100b are provided at bottom portion of the frame structure 202 for connecting with the tubes 204, 206 extending on the right and left side of the vehicle 200.
[042] In the present embodiment, for the mounting shaft 100b, the first end 106 is the end extending towards the center tube 204b and the second end 110 is the end extending towards the side tube 206a.
[043] In an embodiment, each of the mounting shafts 100a, 100b is a T-shaped member or a Y shaped member, as per design of the frame structure 202. Thus, the shape of the mounting shaft is selected based on the constructional requirement of the frame structure 202.
[044] In an embodiment, the mounting shafts 100a, 100b are manufactured by forging process, and thus is a single piece structure. Such a construction of the mounting shafts 100a, 100b eliminates welding operations thereon, enhancing its structural strength and rigidity.
[045] Advantageously, the present invention provides the mounting shafts 100a, 100b, which provides a means for mounting the tubes 204, 206, 208a of the frame structure 208 with minimal welding joints, thereby improving overall strength and rigidity of the frame structure 208. Also, the mounting shafts 100a, 100b being forged is devoid of internal voids or cracks, thereby further enhancing strength of the frame structure 202. Additionally, the mounting shafts 100a, 100b include one or more mounting bosses 116 which facilitate mounting of components with minimal welding operations, consequently improving strength of the frame structure 202.
[046] 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.