Description: A METHOD FOR MANUFACTURING A WHEEL DISC

TECHNICAL FIELD
[0001] The present subject matter described herein relates to a wheel of an automobile, more particularly, the present invention relates to a method of manufacturing a disc for an automobile to reduce thickness of the disc at an area that is not exposed to loads.

BACKGROUND
[0002] Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
[0003] The wheel disc and rim make up the majority of a wheel, which is a crucial safety component of a vehicle. The wheel disc is often produced using shaping methods including stamping and spinning, and it is then joined with the rim via interference assembly and welding.
[0004] Each process alters and distributes the residual stress's condition. Consequently, the manufacturing process results in the extensive and complex residual stress. The wheel, once mounted to the vehicle, supports the weight of the vehicle due to gravity as well as dynamic loads from braking, turning, and uneven roads.
[0005] The most popular technique for creating discs is the stamping process, which involves cutting out the circular blank from a rectangular plate. To make it easier to attach the wheel on the vehicle, the material's core is perforated after being pressed into the desired shape. A significant percentage of the disc-making process is lost due to design and engineering waste since a strip of a specified size is used.
[0006] Also, it should be remembered that the stress pattern on a wheel often varies from part to section. The cross section of the disc has the same thickness during the stamping operation.
[0007] Ref. to Fig. 1. The existing process of manufacturing disc includes using a rectangular sheet of uniform thickness. Further a draw is formed in the sheet using a hydraulic press operation. In next step, a plurality of bolt holes (101) and a plurality of hub holes (102) are punched in the rectangular sheet by using mechanical press operation such that the bolt holes (101) and the plurality of hub holes (102) are pierced from the sheet by a die during the mechanical press operation.
[0008] The circumferential area (A) between the hub holes (102) and the lug holes (101) is not exposed to higher loads during the service life. Hence, the thickness of the circumferential area (A) can be reduced to make the wheel lighter without effecting endurance life of the wheel.
[0009] Thus, the present invention aims to reduce the thickness of the circumferential area (A) as compared to the thickness of the wheel disc at a lug hole portion or a hub hole portion.

OBJECTS OF THE DISCLOSURE
[0010] It is therefore the object of the present disclosure to overcome the aforementioned and other drawbacks in prior method/product/apparatus.
[0011] It is a primary object of the present disclosure is to provide a reduce thickness at a circumferential area (A) on a wheel disc.
[0012] It is another object of the present disclosure to make the wheel lighter without effecting endurance life of the wheel.
[0013] It is another object of the present disclosure a provide a method of manufacturing the wheel disc that is cost effective.
[0014] 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
[0015] 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.
[0016] The present disclosure offers a solution in the form of a method for manufacturing a wheel disc. The method includes forming a hole of a predetermined radius in a sheet with a uniform thickness. The wheel disc is manufactured from the sheet, reducing a sheet thickness of a first area around the hole by a roller tool. The first area is at a pre-determined distance from the hole, forming a plurality of hub holes in a second area around the hole. The second area is between the first area and the hole, forming a plurality of lug hole pairs in a third area around the first area and trimming a plurality of edges of the sheet around the third area for manufacturing the wheel disc.
[0017] In an aspect of the disclosure, the method further comprises forming a buldge due to sudden rise in matrial thickness near to the outer edge of the flow-formed area of the sheet.
[0018] In an aspect of the disclosure, the sheet is clamped around a mandrel via the hole for reducing the sheet thickness of the first area.
[0019] In an another aspect of the disclosure, the plurality of hub holes are formed at a plurality of locations equidistant with one another in the second area.
[0020] In an another aspect of the disclosure, the plurality of lug hole pairs are formed at a plurality of locations equidistant with one another on the third area, wherein a distance between each lug hole amongst each lug hole pair is equal
[0021] In an aspect of the disclosure, the sheet thickness of the first area is reduced between 10%-40 % of an original thickness of the sheet.
[0022] In an aspect of the disclosure, the first area, the second area, and the third area are circular in shape.
[0023] 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
[0024] 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 reference like 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:
[0025] Fig. 1 is the illustration of a wheel disc according to the prior art;
[0026] Fig. 2 illustrates a method for manufacturing a wheel disc according to the present disclosure;
[0027] Fig. 3a illustrates a hole on a sheet according to the present disclosure;
[0028] Fig. 3b illustrates formation of a first area according to the present disclosure;
[0029] Fig. 3c illustrates shaped wheel disc according to the present disclosure;
[0030] Fig. 3d illustrates pierced the lug holes and hub holes according to the present disclosure;
[0031] Fig. 3e illustrates trimmed edges on the wheel disc according to the present disclosure;
[0032] Fig. 4 illustrates variable thickness on a wheel disc cross section according to the present disclosure.
[0033] 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
[0034] 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.
[0035] 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.
[0036] In accordance with this invention, the present invention discloses of a method for manufacturing a wheel disc that is lightweight. The present invention reduces the thickness of a first area as compared to the thickness of the disc at a second area and a third area.
[0037] Referring to Fig. 2 and Fig. 3a, a method (200) for manufacturing a wheel disc is illustrated. The first step (201) of the method includes forming (201) a hole (301) in a sheet (302) made of metal alloys. The sheet (302) has a predertermined thickness and the thickness may be uniform throughout the entire sheet (302).
[0038] The sheet (302) is further processed to form the hole (301) by a mechanical press. The mechanical press punches the hole (301) preferably in the middle portion of the sheet (302). Further, the hole (301) may be of a predetermined radius is produced to fit on a mandrel. The mandrel is used for clamping the sheet (302) to perform various processes. The sheet (302) is clamped around the mandrel via the hole (301) for reducing the sheet thickness of the first area (303).
[0039] Referring to Fig. 2 and Fig. 3b, the second step (202) comprises of reducing a sheet thickness at a first area (303) around the hole (301). The sheet thickness may be reduced by using a roller tool on the sheet. Further, for the reducing the sheet thickness of the first area, the sheet (302) may be clamped around the mandrel via the hole (301).
[0040] Further, the sheet (302) may be rotated on the mandrel and the sheet thickness of the first area (303) is reduced by using a roller tool on the first area (303). to achieve the variation in the thickness of the first area (303) using the flow forming process with respect to the sheet (301). During flow-forming, the forming tool\roller stops near the outer edge of the rotating sheet (302) such that sufficient material is available on the sheet on entire circumferential area that is not flow-formed. This is done to prevent collision of tool\roller with the outer edge of the sheet (302).
[0041] As shown in Fig. 3b and Fig 4, a bulge (309) is formed due to sudden rise in material thickness near the outer edge of the flow-formed area of the sheet (302). Also, the first area (303) is at a pre-determined distance from the hole (301) to create a separation between the mounting area and the non mounting area. Here the mounting area may be denoted to be the area where a plurality of bolts are fastened to mount the disc to the wheel.
[0042] Referring to Fig. 2 and Fig. 3c, the third step (203) comprises of forming/redrawing the final shape of the disc via press forming/redraw method by using hydraulic press operation.
[0043] Referring to Fig. 2 and Fig. 3d, the fourth step (204) comprises of forming a plurality of hub holes (304) in a second area (305). Further, the second area (305) is between the first area (303) and the hole (301). The second area (305) may be preferably circular and may be provided adjacent around the hole (301). The hub holes (304) are formed on the second area (305) by a hydraulic press.
[0044] The hub holes (304) are provided to mount the second area (305) to the wheel of an automobile. Also, the hub holes (304) are formed at a plurality of locations on the second area (305). Further, the hub holes (304) are equidistant with one another on the second area (305). The hub holes are used to attach the disc (complete disc-rim assembly) with a vehicle hub by passing and tightening the bolts through the hub holes (304) and the vehicle hub.
[0045] The fifth step (205) comprises of forming a plurality of lug hole pairs (306) in a third area (307). The third area (307) is formed after the first area (303). The lug hole pairs (306) are pierced in the sheet (302) by the hydraulic press.
[0046] Further, the plurality of lug hole pairs (306) are formed at a plurality of locations equidistant with one another in the third area (307). Also, the distance between each lug hole amongst each lug hole pair (306) may be equal. Also, the first area, the second area, and the third area are circular in shape. The lug holes (306) are attach the disc with the rim. The lugs are welded on the rim and the disc is attached with the rim by passing bolts through the lug holes (306) in the disc and through the lugs welded on the rim.
[0047] Referring to Fig. 2 and Fig. 3e, the last step (206) comprises of trimming a plurality of edges (308a, 308b, 308c, 308d) of the sheet (302) around the third area (307) by the mechanical press for manufacturing the wheel disc. The disc is made round from corners such that it suits with profile of the rim. Therefore, the final disc that is formed has a variable thickness.
[0048] Referring to Fig. 4, The first area (303) has considerably reduced thickness in comparison to the second area (305) and the third area (307). T is the original thickness on the second area (305) and the third area (307) while the reduced thickness T1 is produced on the first area (303) by the flow forming process as described in the second step (202). A bulge (309) is formed due to sudden rise in material thickness near the outer edge of the flow-formed area of the sheet (302).
[0049] The thickness is reduced in the first area (303) as the first area (303) is not exposed to higher loads during the service life. Furthermore, the tensile strength of the first area (303) is increased between 10%-40% due to strain hardening or grain refinement.
[0050] Also, there is a thickness reduction between 10%-40% by flow forming process in the first area (303).
TECHNICAL ADVANTAGES
[0051] With the help of the solution as proposed herein in the context of the present disclosure, there is a thickness reduction between 10%-40% by flow forming process in the first area.
[0052] With the help of the solution as proposed herein, low stress values are obtained and the wheel is able to withstand the given load after removing extra material from the first area.
[0053] 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.”
[0054] 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 end 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.
, Claims:We claim:
1. A method (200) for manufacturing a wheel disc, the method (200) includes the following steps:
forming (201) a hole (301) of a predetermined radius in a sheet (302) with a uniform thickness, wherein the wheel disc is manufactured from the sheet;
reducing (202), by a roller tool, a sheet thickness of a first area (303) around the hole (301), wherein the first area (303) is at a pre-determined distance from the hole (301);
forming/redrawing (203) final shape of the sheet (302) into a disc via press forming/redraw method upon reducing the sheet thickness of the first area (303);
forming (204) a plurality of hub holes (304) in a second area (305) around the hole (301), wherein the second area (305) is between the first area (303) and the hole (301);
forming (205) a plurality of lug hole pairs (306) in a third area (307) around the first area (303); and
trimming (206) a plurality of edges (308a, 308b, 308c, 308d) of the sheet (302) around the third area (307) for manufacturing the wheel disc.

2. The method (200) as claimed in claim 1, further comprises forming a buldge (309) due to sudden rise in matrial thickness near to the outer edge of the flow-formed area of the sheet (302).

3. The method as claimed in claim 1, wherein the sheet (302) is clamped around a mandrel via the hole for reducing the sheet thickness of the first area (303).

4. The method as claimed in claim 1, wherein the plurality of hub holes (304) are formed at a plurality of locations equidistant with one another in the second area (305).

5. The method as claimed in claim 1, wherein the plurality of lug hole pairs (306) are formed at a plurality of locations equidistant with one another on the third area (307), wherein a distance between each lug hole amongst each lug hole pair is equal.

6. The method as claimed in claim 1, wherein the sheet thickness of the first area (303) is reduced between 10%-40% of an original thickness of the sheet (302).

7. The method as claimed in claim 1, wherein the first area, the second area, and the third area are circular in shape.