DESC:FIELD OF THE INVENTION
[001] Present disclosure relates to an axle spindle for a vehicle. More particularly, the present disclosure relates to an axle spindle for a heavy vehicle.

BACKGROUND OF THE INVENTION
[002] Vehicles, such as heavy vehicles including but not limiting to trailer vehicles, comprise an axle as an essential component. For many years, the heavy-duty vehicle industry has utilized wheel end assemblies mounted on each end of the axle. Axle spindles are components used on the axle of the vehicle to receive and support the wheel end assembly.
[003] Conventionally, manufacture of axle spindles employs a casting process. However, casted axle spindles often exhibit lower strength due to inherent flaws introduced during casting process, such as microscopic defects and material inconsistencies. These imperfections undermine the overall durability and robustness of the axle spindle. Additionally, casted axle spindles have rougher surface finishes and less precise dimensions further compromising the structural integrity of the axle spindle. This results in the axle spindle that is lacking the required dimensional accuracies on the related surfaces, leading to either misdirected force or inadequate clamping force, thereby forcing the axle to work in unfavorable operating conditions. Moreover, the cast axle spindle cannot withstand shock or dynamic loads acting thereon during riding of the vehicle.
[004] In addition, heavy vehicles are frequently subjected to overloading beyond their permissible limit. Existing axle spindles are unable to accommodate such overloads. Due to the aforementioned forces or load, an imperative limitation is the failure of the conventional axle spindle. Failure of axle spindle can lead to sudden detachment of the wheels from the axle beam, which can lead to safety hazards for the user as well as other vehicles in proximity.
[005] In view of the above, there is a need for an axle spindle to overcome one or more limitations stated above.

SUMMARY OF THE INVENTION
[006] In one aspect, the present invention is directed towards an axle spindle for a vehicle. The axle spindle has a cylindrical portion and a tubular skirt portion extending from one end of the cylindrical portion. The tubular skirt portion is integrally formed with the cylindrical portion by forging.
[007] In an embodiment, the cylindrical portion is integrally formed with the tubular skirt portion with one of a stepped profile and an L-shaped profile.
[008] In an embodiment, the cylindrical portion has one or more bearing support surfaces. The one or more bearing support surfaces are spaced apart and in coaxial alignment with one another along the axle spindle.
[009] In an embodiment, the one or more bearing support surfaces are formed in a single set-up such that each of the bearing surfaces of the one or more bearing support surfaces are in parallel alignment to each other. The one or more bearing support surfaces are induction hardened.
[010] In an embodiment, the tubular skirt portion forms an inboard portion of the axle spindle. The cylindrical portion along with one or more bearing support surface forms an outboard portion of the axle spindle. The inboard portion is assembled onto an axle beam and the outboard portion forming a shaft portion receives and supports a wheel hub.
[011] In an embodiment, a flange portion is adapted to engage with a rim of the axle beam. The flange portion separates the inboard portion and the outboard portion.
[012] In an embodiment, the inboard portion being adapted to interference-fit with the axle beam and flange portion welded onto to a rim of the axle beam.
[013] In an embodiment, the axle spindle has a keyway adapted to slidably receive a washer and a through hole adapted to receive a lock pin for locking an axle nut.
[014] In an embodiment, the axle spindle is integrated with a dead axle.

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 sectional view of an axle spindle for a vehicle, in accordance with an embodiment of the present invention.
Figure 2 is a perspective view of the axle spindle, in accordance with an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION
[016] The present disclosure provides an axle spindle for a vehicle. More particularly, the present disclosure relates to the axle spindle for a heavy vehicle. The axle spindle in the present invention is hollow in shape and is manufactured by forging. Thus, the axle spindle of the present invention is characterized by uniform strength with high load bearing capacity and rigidity resulting in a fatigue resistant axle spindle. Therefore, the axle spindle is capable of bearing heavy loads, undulations and shocks. In an embodiment, the vehicle can be a trailer, sub-trailer or any other multi-wheeled vehicle as per requirement.
[017] For the purpose of the present invention, a longitudinal axis of the vehicle refers to an axis along a length of the vehicle, a lateral axis of the vehicle refers to an axis along a width of the vehicle and a vertical axis of the vehicle refers to an axis along the height of the vehicle.
[018] Figure 1 is a schematic view of an axle spindle 100 for a vehicle (not shown) in accordance with an exemplary embodiment of the present invention. The axle spindle 100 comprises a cylindrical portion 102 and a tubular skirt portion 104 extending from one end of the cylindrical portion 102. The cylindrical portion 102 is oriented about a laterally or about a left-right direction of the vehicle. The tubular skirt portion 104 is integrally formed with the cylindrical portion 102 by forging or forging process. In an embodiment, the cylindrical portion 102 is integrally formed with the tubular skirt portion 104 with a stepped profile or an L-shaped profile. The cylindrical portion 102 is a primary load-bearing section, transmitting forces between a wheel hub (not shown) and an axle beam (not shown). The tubular skirt portion 104 extends from one end of the cylindrical portion 102. The tubular skirt portion 104 is adapted to mount the axle beam. The integral formation of the cylindrical portion 102 and the tubular skirt portion 104 distributes load stress evenly across the axle spindle 100, enabling the axle spindle 100 to withstand heavy impacts and vibrations.
[019] The cylindrical portion 102 comprises bearing support surfaces 106a and 106b. The bearing support surfaces 106a and 106b are spaced apart and in coaxial alignment with one another along the axle spindle 100. The bearing support surfaces 106a and 106b are induction hardened adding to the rigidity of the axle spindle 100. The bearing support surfaces 106a and 106b are formed in a single set-up ensuring that both bearing surfaces 106a and 106b are in parallel alignment to each other. Thread forming on the axle spindle 100 is aligned with the bearing support surfaces 106a and 106b. Such a structural feature of one or more bearing surfaces 106a and 106b ensures proper wheel hub seating, reducing tire wear and misalignment issues.
[020] The tubular skirt portion 104 forms an inboard portion 108 of the axle spindle 100. The cylindrical portion 102, the bearing support surface 106a and the bearing support surface 106b forms an outboard portion 110 of the axle spindle 100. The inboard portion 108 is assembled onto the axle beam. The outboard portion 110 forming a shaft portion receives and supports the wheel hub. The wheel hub in turn mounts and supports a wheel end assembly (not shown) of the vehicle. The inboard portion 108 is responsible for transferring loads from the wheel hub assembly to the axle beam. The outboard portion 110 ensures even weight distribution across the wheel end assembly thereby reducing localized stress and preventing premature failure of wheel bearings and tires.
[021] Further, a flange portion 112 of the axle spindle 100 engages with a rim of the axle beam. The flange portion 112 separates the inboard portion 108 and the outboard portion 110. In an embodiment, the inboard portion 108 may refer to a portion of the axle spindle 100 that is accommodated within the axle beam. In an embodiment, the L-shaped profile is machined such that, an interference fit is established with the inboard portion 108 of the axle spindle 100. The interference fit ensures a firm grip of the axle spindle 100 in the axle beam. In an embodiment, the flange portion 112 is welded onto the rim of the axle beam, upon interference fit between the ends with the inboard portion 108 through conventional welding techniques known in the art, thereby locking the axle spindle 100 onto the axle beam. In an embodiment, the fitment of the axle spindle 100 in the axle beam is through interference fit of 0.02mm to 0.100 mm to provide a firm grip and then welded all around to give a final locking. This prevents relative motion between the axle spindle 100 and the axle beam under heavy loads.
[022] In an embodiment, the axle spindle 100 is structurally integrated with a dead axle (not shown) to enhance load-bearing efficiency, stability and durability in heavy-duty vehicles. A dead axle, also known as a non-driven axle, is adapted to support the weight and maintain wheel alignment of the vehicle without transmitting power to the wheels. The integration of the axle spindle 100 with the dead axle ensures secure attachment and improved load distribution.
[023] Referring to Figure 2 in conjunction with Figure 1, the axle spindle 100 is hollow in shape. The hollow structure of the axle spindle 100 reduces overall weight while maintaining high structural integrity, thereby improving fuel efficiency and vehicle performance. The axle spindle 100 comprises a keyway 114 adapted to slidably receive a washer (not shown). The washer prevents uneven pressure on the one or more bearing surfaces 106a, 106b. Further, the axle spindle 100 comprises a through hole 116 adapted to receive a lock pin for locking an axle nut (not shown). This prevents loosening of the axle nut during vehicle operation. In an embodiment, the axle spindle 100 is made of forged 1045 steel. Thus, the axle spindle 100 is characterized with a higher loading capacity and strength.
[024] In an embodiment, the axle spindle 100 is manufactured by forging, which causes metal grains in the axle spindle 100 to elongate and align along the direction of applied force, resulting in a denser and more uniform microstructure having lesser internal voids and imperfections compared to conventional axle spindle manufactured by casting. Therefore, the forged axle spindle 100 in accordance with the present embodiment of the invention has greater strength, greater resistance to wear, greater fatigue resistance and better impact resistance and being hollow is lighter in weight as compared to conventional axle spindles.
[025] Advantageously, the axle spindle according to the present invention is formed by forging, thereby ensuring uniform strength and wear resistance in the axle spindle. Also, the axle spindle is made through forged 1045M steel providing additional strength to the axle spindle. Also, the induction hardened bearing seating surfaces makes the axle spindle rigid, high load bearing and fatigue resistant, thereby providing additional strength to bear heavy loads and shocks. The hollow design makes the axle spindle lighter in weight. The improved load capacity of the axle spindle also avoids any failure under irresponsible overloading. Additionally, machining of the ends of the axle spindle ensures interference fit with the axle beam, thereby enabling a firm grip of the spindle in the axle beam.
[026] The foregoing description of the invention has been set merely to illustrate the invention and is not intended to be limiting. Since the modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to the person skilled in the art, the invention should be construed to include everything within the scope of the disclosure.

List of reference numerals
100 - Axle Spindle of a vehicle
102 - Cylindrical portion
104 - Tubular skirt portion
106a,106b - Bearing support surfaces
108 - Inboard portion
110 - Outboard portion
112 - Flange
114 - Keyway
116 - Through hole
,CLAIMS:We Claim
1. An axle spindle (100) for a vehicle, the axle spindle (100) comprising:
a cylindrical portion (102); and
a tubular skirt portion (104) extending from one end of the cylindrical portion (102), the tubular skirt portion (104) being integrally formed with the cylindrical portion (102) by forging.

2. The axle spindle (100) as claimed in claim 1, wherein the cylindrical portion (102) being integrally formed with the tubular skirt portion (104) with one of a stepped profile and an L-shaped profile.

3. The axle spindle (100) as claimed in claim 1, wherein the cylindrical portion (102) comprises one or more bearing support surfaces (106a, 106b), the one or more bearing support surfaces (106a, 106b) are spaced apart and in coaxial alignment with one another along the axle spindle (100).

4. The axle spindle (100) as claimed in claim 3, wherein the one or more bearing support surfaces (106a, 106b) are formed in a single set-up such that each of the bearing surfaces of the one or more bearing support surfaces (106a, 106b) are in parallel alignment to each other, the one or more bearing support surfaces (106a, 106b) being induction hardened.

5. The axle spindle (100) as claimed in claim 1, wherein the tubular skirt portion (104) forms an inboard portion (108) of the axle spindle 100, the cylindrical portion (102) along with one or more bearing support surface (106a, 106b) forms an outboard portion (110) of the axle spindle (100) such that the inboard portion (108) being assembled onto an axle beam and the outboard portion (110) forming a shaft portion receives and supports a wheel hub.

6. The axle spindle (100) as claimed in claim 5 comprising a flange portion (112) adapted to engage with a rim of the axle beam (100), the flange portion (112) separates the inboard portion (108) and the outboard portion (110).

7. The axle spindle (100) as claimed in claim 6, wherein the inboard portion (108) being adapted to interference-fit with the axle beam and flange portion (112) welded onto to a rim of the axle beam.

8. The axle spindle (100) as claimed in claim 1 comprising a keyway (114) adapted to slidably receive a washer, and a through hole (116) adapted to receive a lock pin for locking an axle nut.

9. The axle spindle (100) as claimed in claim 1, wherein the axle spindle (100) being integrated with a dead axle.

Dated this 8th day of February 2024.
RAMKRISHNA FORGINGS LIMITED
By their Agent & Attorney

(Adheesh Nargolkar)
of Khaitan & Co
Reg No IN/PA-1086