The present subject matter described herein relates to a reinforcement structure for a rear axle of a vehicle. More particularly, the present invention relates to a reinforcement structure having a U-shaped frame braced with a rear axle of a vehicle providing sturdy structure to bear the dynamic loads.
BACKGROUND
[0002] Rear axle assemblies are well-known systems widely used in most of the vehicles. These axle assemblies contain a variety of components that are designed to transfer rotational power from a vehicle's engine to its wheels. An axle assembly requires a differential that is assisted rotating inside a non-rotating housing. The differential is linked between an input drive shaft running from the engine of the vehicle and a pair of output axle shafts connecting to the wheels.
[0003] The shafts of the axles are located in respectively non-rotating tubes that are fixed to the carrier and the differential rotation by the drive shaft allows the axle shafts to rotate correspondingly. The carrier and the tubes form a housing for these axle assembly drivetrain parts, as long as the differential and axle shafts are assisted for rotation in it.
[0004] In the conventional design, on a central housing 11 as shown in FIG.l, an elongated arm 11a at its one end 19 is welded to the axle tube 12 circumferentially. This component is a prime load carrying member and while experiencing dynamic loads the weld joint between axle tube and sheet metal housing becomes critical region experiencing high stresses. In such a situation, when the welding process is susceptible to numerous process variations, improper welding may occur and this situation will deteriorate the quality of the weld joint thereby affecting the part performance. Hence it is required to increase the

robustness of rear axle design so that rear axle can experience dynamic loads without any failure.
[0005] The prior art US8776374B2 relates to a method and apparatus for manufacturing an axle for a vehicle. In this invention, the rear axle includes an axle housing and a tubular spindle welded to each other circumferentially.
[0006] The prior art US8109000B2 relates to axle assemblies and more particularly to a Salisbury axle having contoured axle tubes. The prior art discloses a rear axle that includes a carrier housing and a pair of axle tubes that are welded to each other circumferentially.
[0007] Technical problem: In the existing prior arts, there is no provision of increasing the robustness or providing structural rigidity to the weld joint. Weld region between the center housing and axle tube is susceptible to failure due to numerous process variations and dynamic loads experienced by the axle.
[0008] Technical solution: Thus, there is a need for a new design that increases the strength of welded joint joining the elongated arm of the central housing with the axle tube of the rear axle in the vehicle. Furthermore, the design must provide a gradual distribution of weld stress.
OBJECTS OF THE DISCLOSURE
[0009] It is therefore an object of the present disclosure to overcome the aforementioned and other drawbacks in prior method/product/apparatus.
[0010] It is a primary object of the present disclosure to provide a reinforcement structure in weld joint between elongated arm of a central housing and an axle tube of a rear axle in a vehicle.
[0011] It is another object of the present disclosure to provide an unsymmetrical recess to maintain clearance between circular weld joint and the reinforcement structure.

[0012] It is another object of the present disclosure to increase robustness of weld joint by keeping length of the reinforcement structure more on axle tube side than the central housing side.
[0013] It is another object of the present disclosure to provide an unsymmetrical cut-out for stress relief on the trimline edge.
[0014] It is another object of the present disclosure to provide dual flange trimline profile weld line (combination of straight and curved profile) for gradual distribution of dynamic loads.
[0015] It is another object of the present disclosure to provide a jig-hole in the reinforcement bracket to drain out water.
[0016] It is another object of the present disclosure to increase the section modulus of the joint, thereby increasing the part durability performance.
[0017] These and other objects and advantages of the present subject matter will be apparent to a person skilled in the art after consideration of the following detailed description taken into consideration with accompanying drawings in which preferred embodiments of the present subject matter are illustrated.
SUMMARY
[0018] Solution to one or more drawbacks of existing technology and additional advantages are provided through the present disclosure. Additional features and advantages are realized through the technicalities of the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are considered to be a part of the claimed disclosure.
[0019] The present disclosure offers a solution in the form of configuration with inventive components forming an assembly with precise tolerance band, precise mounting of the rear axle housing, increasing the strength of weld joint and providing a sturdy structure.

[0020] The present disclosure discloses a reinforcement structure for a rear axle of a vehicle including a U-shaped frame braced at a weld joint joining a central housing and an axle tube of the rear axle.
[0021] In an aspect, the frame has an unsymmetrical recess carved on each of lateral walls, accommodating the weld joint in the recess.
[0022] In an aspect, the length of the frame is more on the axle tube side than on the central housing side.
[0023] In an aspect, the frame has at least one concave unsymmetrical cut-out at opposite ends of the reinforcement structure facing outside.
[0024] In an aspect, the frame has dual weld line, a combination of straight and curved profile, attached with the axle tube towards an elongated face of the recess and attached with the central housing towards afore part of the recess.
[0025] In an aspect, the frame has a plurality of holes positioned at bottom surface.
[0026] In another aspect, the hole has an embossed structure.
[0027] In another aspect, the frame is welded with the rear axle of the vehicle.
[0028] In another aspect, the unsymmetrical recess carved maintains clearance between a circular weld joint and the frame.
[0029] In another aspect, the frame is welded with the axle tube using dual weld line (combination of straight and curved profile).
[0030] In yet another aspect, the parabolic flange trimline is welded with the central housing.
[0031] In yet another aspect, the weld joint is a circular weld joint joining an elongated arm of the central housing and the axle tube.
[0032] The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features

described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0033] It is to be noted, however, that the appended drawings illustrate only typical embodiments of the present subject matter and are therefore not to be considered for limiting of its scope, for the present disclosure may admit to other equally effective embodiments. The detailed description is described with reference to the accompanying figures. In the figures, a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the figures to refer features and components. Some embodiments of system or methods or structure in accordance with embodiments of the present subject matter are now described, by way of example, and with reference to the accompanying figures, in which:
[0034] FIG. 1 is an illustrative view of the rear axle of a vehicle;
[0035] FIG. 2 is an illustrative view of a reinforcement structure in accordance with an embodiment of the present disclosure;
[0036] FIG. 3 is a perspective view of the U-shaped frame of the reinforcement structure in accordance with an embodiment of the present disclosure;
[0037] FIG. 4 is alternate views from the top and bottom of the U-shaped frame in accordance with an embodiment of the present disclosure; and
[0038] FIG. 5 is an alternate illustrative view of the reinforcement structure welded to the rear axle in accordance with an embodiment of the present disclosure.
[0039] The figures depict embodiments of the present subject matter for illustration only. A person skilled in the art will easily recognize from the following description that alternative embodiments of the structures and methods

illustrated herein may be employed without departing from the principles of the disclosure described herein.
DETAILED DESCRIPTION
[0040] While the embodiments of the disclosure are subject to various modifications and alternative forms, a specific embodiment thereof has been shown by way of example in the figures and will be described below. It should be understood, however, that it is not intended to limit the disclosure to the particular forms disclosed, but on the contrary, the disclosure is to cover all modifications, equivalents, and alternatives falling within the scope of the disclosure.
[0041] The terms "comprises", "comprising", or any other variations thereof used in the disclosure, are intended to cover a non-exclusive inclusion, such that a device, system, assembly that comprises a list of components does not include only those components but may include other components not expressly listed or inherent to such system, or assembly, or device. In other words, one or more elements in a system or device proceeded by "comprises... a" does not, without more constraints, preclude the existence of other elements or additional elements in the system or device.
[0042] Referring to FIG. 1, a rear axle 10 of the vehicle is disclosed. The rear axle 10 of the vehicle has predominantly a central housing 11 with an elongated arm 11a joined by circular weld joint 19 with an axle tube 12 to form a rear axle assembly. As it is understood, the rear axle 10 is used to carry the weight of the vehicle as well as to facilitate transmission of the power to rear wheels. Generally, the rear axle assembly supports the vehicle weight and drives the rear wheels at the same time. The rear axle assembly encompasses the rear axle shafts that drive the wheels and a differential that provides relative movement between the two wheels whenever necessary.
[0043] As discussed in the background section of the present disclosure, the weld joint 19 is prone to failure or breakage due to dynamic loads. The present subject

matter aims at increasing the robustness of welded joint 19 by providing a reinforcement structure to the rear axle 10. This aim is achieved by providing the reinforcement structure with a U-shaped frame 13. As shown in FIG. 2, the U-shaped frame 13 is provided on a circular weld joint 19 that is being welded to the central housing 11 at one end and to the axle tube 12 at other end through arc welding.
[0044] The frame 13 is a U-shaped structure, which is designed with an intention to have higher section depth to increase the section modulus of the weld joint 19, which will increase the load bearing capacity of weld joint 19 under application of dynamic loads. The weld joint 19 is susceptible to welding process related deviations, which can deteriorate the part quality and affect its performance. Now, as the reinforcement structure is proposed in accordance with the present disclosure, the reinforcement structure improves the design robustness by improving the system overall quality and performance. The shape of the reinforcement structure has key features that is manufactured considering the manufacturability, the structural rigidity/strength and the end application viewpoint.
[0045] Referring to FIG. 3, the frame 13 is a U-shaped structure and has two lateral walls on either side of the frame 13.
[0046] The frame has an unsymmetrical recess 14 carved on each lateral wall 20 of the frame 13. The recess 14 is carved in such a manner that when the frame 13 is joined or welded to the rear axle 10 of the vehicle, the recess 14 accommodates the weld joint 19 within the recess 14. In an aspect, the recess 14 is carved in specific manner such that it has two distinct ends. The recess 14 has an elongated face 14a carved towards the larger part or the posterior section of the frame 13 and afore part 14b towards the anterior section of the frame 13.
[0047] The recess 14 maintains clearance between the circular weld joint 19 and the reinforcement structure.

[0048] The depth and contour of the recess 14 are in accordance with the requirement of increased surface area for the recess 14. This helps in reducing the local stress concentration. It is understood that the depth of the recess 14 until a threshold is directly proportional to the stress levels.
[0049] In the frame 13, a dual weld line 16a which is a combination of straight and curved proffle is present. The dual weld line 16a extends longitudinally on an upper peripheral surface of the lateral walls 20 towards the larger part or the posterior section of the frame 13.
[0050] The dual weld line 16a is provided at one distinct end of the recess 14. That is, towards the elongated face 14a of the recess 14. Further, a parabolic flange trimline 16b is provided on the upper peripheral surface of the lateral walls 20. The parabolic flange trimline 16b is provided on a fore part 14b towards the anterior section of the frame 13. The parabolic flange trimline 16b attaches with the central housing 11 or preferably to the elongated arm 11a of the central housing 11.
[0051] The dual weld line 16a acts as a welding edge where the reinforcement trimline proffle matches the mating tube and housing proffle. In the present disclosure, the object to adopt a dual weld line is to achieve gradual distribution of weld stress.
[0052] In the present disclosure, the frame 13 has at least one unsymmetrical cut-out 15 at opposite ends of the frame 13 facing outside. The unsymmetrical cut-out 15 are responsible for relieving stress on the trim line edges of the frame 13.
[0053] Referring to FIG. 4, a plurality of holes 17 are formed at bottom surface of the frame 13. The holes 17 are provided with embossed structures. The holes 17 are used for positioning of the frame 13 while welding onto the rear-axle 10 during assembly. Further, the embossed structure is helpful in acting as provision for water and dirt drainage on the flat bottom face of the frame 13.
[0054] Referring to FIG. 5, an alternative view of the reinforcement structure for the rear axle 10 is illustrated. The U-shaped frame 13 of the reinforcement

structure is braced, preferably welded, with the rear-axle 10 of the vehicle in accordance with the present disclosure. The dual weld line 16a towards the elongate face at the posterior section of the frame 13 is welded to the axle tube 12. The parabolic flange trimline 16b towards the fore part 14b at the anterior section of the reinforcement 13 is welded to the central housing 11 or preferably to the elongated arm 11a of the central housing 11. The U-shaped frame 13 is braced with the rear-axle 10 in such a way that the asymmetrical recess 14 at the lateral walls of the frame 13 accommodates the circular weld joint 19, which joins the central housing 11 and the axle tube 12. The recess 14 accommodates the weld joint 19 ensuring that the recess 14 maintains a clearance between the circular weld joint 19 and the reinforcement structure.
[0055] Further, an unsymmetrical structure 18 about a circumferential weld is created such that length of the frame 13 is kept more on the axle tube 12 side than on the housing 11a side. For example, if "a" is length of the frame 13 on the housing 11a side and "b" is length of the frame 13 on the axle tube 12 side, then b>a. Such configuration of the frame 13 helps in increasing the robustness of weld joint 19.
[0056] The reinforcement structure proposed herein achieves the following advantages:
(a) Unequal length about circumferential weld joint with more length on axle tube side than on central housing side helps in increasing the robustness of weld joint, thereby improving performance of suspension system;
(b) Increase in section modulus of the weld joint thereby increasing the part durability performance; and
(c) Facilitates scope of further shape optimization of tube to reduce part cost and weight.
[0057] It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended

claims) are generally intended as "open" terms (e.g., the term "including" should be interpreted as "including but not limited to," the term "having" should be interpreted as "having at least," the term "includes" should be interpreted as "includes but is not limited to," etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation, no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases "at least one" and "one or more" to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles "a" or "an" limits any particular claim containing such introduced claim recitation to disclosures containing only one such recitation, even when the same claim includes the introductory phrases "one or more" or "at least one" and indefinite articles such as "a" or "an" (e.g., "a" and/or "an" should typically be interpreted to mean "at least one" or "one or more"); the same holds true for the use of definite articles used to introduce claim recitations. Also, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of "two recitations," without other modifiers, typically means at least two recitations or two or more recitations). Furthermore, in those instances where a convention analogous to "at least one of A, B, and C, etc." is used, in general, such construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having at least one of A, B, and C" would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances, where a convention analogous to "at least one of A, B, or C, etc." is used, in general, such construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having at least one of A, B, or C" would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It

will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms or both terms. For example, the phrase "A or B" will be understood to include the possibilities of "A" or "B" or "A and B."
[0058] It will be further appreciated that functions or structures of a plurality of components or steps may be combined into a single component or step, or the functions or structures of one-step or component may be split among plural steps or components. The present disclosure contemplates all of these combinations. Unless stated otherwise, dimensions and geometries of the various structures depicted herein are not intended to be restrictive of the disclosure, and other dimensions or geometries are possible. Also, while a feature of the present disclosure may have been described in the context of only one of the illustrated embodiments, such feature may be combined with one or more other features of other embodiments, for any given application. It will also be appreciated from the above that the fabrication of the unique structures herein and the operation thereof also constitute methods in accordance with the present disclosure. The present disclosure also encompasses intermediate and products resulting from the practice of the methods herein. The use of "comprising" or "including" also contemplates embodiments that "consist essentially of or "consist of the recited feature.

WE CLAIM:

1. A reinforcement structure for a rear axle (10) of a vehicle, comprising:
a U-shaped frame (13) braced at a weld joint (19) joining a central housing (11) and an axle tube (12) of the rear axle (10); and
an asymmetrical recess (14) carved on each of lateral walls (20) of the frame (13), accommodating the weld joint (19) in the recess (14),
wherein a length of the frame (13) is more on the axle tube (12) side than on the central housing (11) side.
2. The reinforcement structure as claimed in claim 1, wherein the frame (13) has at least one asymmetrical cut-out (15) at opposite ends of the frame (13) facing outside.
3. The reinforcement structure as claimed in claim 1, further comprising a dual weld line (16a) extending longitudinally on an upper peripheral surface of the lateral walls (20) of the frame (13) is attached with the axle tube (12) towards an elongated face (14a) of the recess (14).
4. The reinforcement structure as claimed in claim 1, further comprising a parabolic flange trimline (16b) provided on an upper peripheral surface of the lateral walls (20) is welded with the central housing (11).
5. The reinforcement structure as claimed in claim 1, wherein a plurality of holes (17) is formed at bottom surface of the frame (13).
6. The reinforcement structure as claimed in claim 1, wherein holes (17) are provided with embossed structure.
7. The reinforcement structure as claimed in claim 1, wherein the recess (14) carved maintains clearance between a circular weld joint (19) and the frame (13).

8. The reinforcement structure as claimed in claim 3, wherein the dual weld line (16a) welded with the axle tube (12) is a combination of straight and curved profile.
9. The reinforcement structure as claimed in claim 1, wherein the weld joint (19) is a circular weld joint joining an elongated arm (11a) of the central housing (11) and the axle tube (12).