Description:TECHNICAL FIELD
[0001] The present disclosure generally relate to the field of automobile wheels. More particularly, it pertains to a method of manufacturing a wheel disc.

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] Wheels form a critical part in automobiles. The wheels have an effect on vehicle stability and driving comfort thereby playing an important role in the safety associated with the vehicles.
[0004] A conventional automobile wheel for a pneumatic tyre typically has two main parts: a disc that is configured to be coupled to a corresponding hub of the vehicle, and a rim that supports the pneumatic tyre. The two parts are typically manufactured separately and joined together, such as by welding or bolting.
[0005] The disc is typically manufactured, as also disclosed by different Patent documents, such as US9630279B2, IN338403B and IN4366/MUM/2015, from a rectangular piece of strip made of metallic materials. The rectangular piece of strip is rolled to form a band, which is welded to form a hoop. Thereafter, the hoop is formed by press operations, spinning process or a combination of the two, to give final shape before machining operations.
[0006] The methods of the cited references have one or more shortcomings. For example, during first shaping /necking, the hoop/disc cylinder is placed on a die and a punch strikes on the hoop/disc cylinder for first necking operation/conical shape operation. To form a symmetrical necking/conical shape on the entire circumference of the hoop/disc cylinder, the hoop/disc cylinder should be placed concentrically with the die. However, the methods discussed above fail to ensure a precise concentric placement of the hoop/disc cylinder in the die. This may lead to disproportionate/ eccentric necking/conical shaping. Improper positioning may also lead to formation of waviness, wrinkles or zigzags on an inner surface of the disc. These drawbacks result in increase in rejection during manufacturing.
[0007] Therefore, there is a need for improved techniques for precise positioning of the hoop/disc cylinder in the die while performing forming operation.

OBJECTS OF THE PRESENT DISCLOSURE
[0008] Some of the objects of the present disclosure, which at least one embodiment herein satisfies, are as listed below.
[0009] It is an object of the present disclosure to provide an improved method for manufacturing a disc wheel that ensures precise concentric positioning of a hoop/disc cylinder in the die while performing forming operations.
[0010] It is an object of the present disclosure to reduce the waves or zigzags formed on an inner surface of the ring.
[0011] It is an object of the present disclosure to provide a method for manufacturing a disc wheel that passively works as a quality control check of welding on the part.
[0012] It is an object of the present disclosure to reduce material wastage in the process of manufacturing the wheel disc.
[0013] It is an object of the present disclosure to increase the thickness at the attachment area/nave contact area without hot forming.
[0014] It is an object of the present disclosure to prepare the band with enough volume of material to address the required thickness at each location.
[0015] It is an object of the present disclosure to achieve the circularity of the component by expanding process.

SUMMARY
[0016] This section is provided to introduce certain objects and aspects of the present disclosure in a simplified form that are further described below in the detailed description. This summary is not intended to identify the key features or the scope of the claimed subject matter.
[0017] In an aspect the present disclosure relates to a method for manufacturing a wheel disc. The method includes providing a rectangular strip made of a metallic material, rolling the rectangular strip to form a band, welding adjacent ends of the band to form a ring, expanding the formed ring to achieve a required diameter and forming the expanded ring to achieve a required shape of the wheel disc. The forming includes a first forming operation to flare a first axial side of the ring in an outward direction to achieve a first conical shape having a first angle at the first axial side; a second forming operation to form a second axial side of the ring in an inward direction to achieve a second conical shape at the second axial side, while simultaneously forming the first axial side to increase the first angle of the first conical shape; and a third forming operation to further form the second conical shape to achieve a flat surface that is perpendicular to an axis of the ring, thereby achieving a required shape of the wheel disc.
[0018] The method may further include forming the second axial side during the second forming operation to achieve the second conical shape that has a larger cone angle than the first angle of the first conical shape. In some embodiments, the method may further include: resting an inner surface of the first conical shape against a respective die of a matching shape during the second forming operation and the third forming operation, thereby ensuring concentric location of the ring in the die.
[0019] In some embodiments, the method includes one or more of the operations such as, piercing all holes, performing flow forming, piercing and coining of vent holes, piercing and coining of bolt holes, spoking and boring and bolt hole drilling on the achieved shape of wheel disc to obtain a final wheel disc.

BRIEF DESCRIPTION OF DRAWINGS
[0020] The accompanying drawings are included to provide a further understanding of the present disclosure and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure. The diagrams are for illustration only, which thus is not a limitation of the present disclosure.
[0021] FIG. 1 illustrates initial processing steps involved for obtaining a ring structure for manufacturing a wheel disc, in accordance with some embodiments of the present disclosure.
[0022] FIG. 2 illustrates an exemplary sectional view showing a first forming operation on the obtained ring structure, in accordance with some embodiments of the present disclosure.
[0023] FIG. 3 illustrates an exemplary sectional view showing a second forming operation on the obtained ring structure, in accordance with some embodiments of the present disclosure.
[0024] FIG. 4 illustrates an exemplary sectional view showing a third forming operation to achieve the disc shape, in accordance with some embodiments of the present disclosure.
[0025] FIG. 5 illustrates variations associated with the first, second, and third forming operations to manufacture the wheel disc, in accordance with some embodiments of the present disclosure.
[0026] FIG. 6 illustrates one or more operations performed on a preformed disc to achieve a final disc, in accordance with some embodiments of the present disclosure.
[0027] FIG. 7 illustrates a first variation associated with the one or more operations performed on a preformed disc to achieve a final disc, in accordance with some embodiments of the present disclosure.
[0028] FIG. 8 illustrates a second variation associated with the one or more operations (800) performed on a preformed disc to achieve a final disc, in accordance with some embodiments of the present disclosure.
[0029] FIG. 9 illustrates a complete process for manufacturing of the wheel disc, in accordance with some embodiments of the present disclosure.
[0030] The foregoing shall be more apparent from the following more detailed description of the invention.
DETAILED DESCRIPTION
[0031] The following is a detailed description of embodiments of the disclosure depicted in the accompanying drawings. The embodiments are in such detail as to clearly communicate the disclosure. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the scope of the present disclosure as defined by the appended claims.
[0032] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the embodiments of the present invention. It will be apparent to one skilled in the art that embodiments of the present invention may be practiced without some of these specific details.
[0033] The present disclosure relates to a method of manufacturing a wheel disc. The wheel disc is manufactured from a steel strip by making a hoop/ring out of the steel strip and subjecting the hoop/ring to first, second, and third forming operations followed by an all hole piercing and a flow forming operation to achieve the final wheel disc.
[0034] Various embodiments of the present disclosure will be explained with reference to FIGs. 1-9.
[0035] FIG. 1 illustrates initial processing steps 100 involved in obtaining a ring structure for manufacturing a wheel disc, in accordance with some embodiments of the present disclosure. In FIG. 1 a step-by-step process for forming the ring/hoop from a metallic strip is shown. The process 100 may include, at step 102, providing a rectangular strip made of metallic material. Further, the process 100 may include at step 104, rolling or coiling the rectangular strip to form a band like structure. The process 100 may include at step 106, welding the adjacent ends of the band to form a ring, wherein the welding process may include, for example, without limitations, a butt-welding process. Upon welding, the process 100 may include at step 108, re-rounding process to obtain the ring/hoop. Further, the process 100 may include at step 108 an expansion process to reduce ovality in the ring and achieve the required diameter for the ring. The expansion process helps in reducing waviness occurring on an inner surface of the ring during further operations and also checks a weld quality between the two adjacent edges of the ring. The expanded ring structure is further subjected to one or more forming operations as will be discussed below with reference to FIGs. 2, 3, and 4 in details.
[0036] FIG. 2 illustrates, through sectional views of input and output, a first forming operation 200 on the obtained ring structure, in accordance with some embodiments of the present disclosure. In FIG. 2 a first forming operation performed on the ring/hoop, which is obtained by the initial processing 100 of the steel strip as mentioned above with reference to FIG. 1, is shown. Referring to FIG. 2, the first forming operation flares a first axial side of the ring, such as the lower side of the ring, as shown in the exemplary illustration of FIG. 2, in an outward direction 202 to achieve a first conical shape having a first angle of A1, at the first axial side. In some embodiments the diameter of one side of the cylindrical ring/hoop is increased by press operation while the diameter of the other side of the ring/hoop remains same. The formed ring is then subjected to further forming operations as explained below with reference to FIGs. 3 and 4. The first forming operation enables the ring to sit concentric with a die or punch so that the further forming operations are performed without any deviation from the concentric position with respect to the position of the ring on the die or the punch, as the case may be.
[0037] FIG. 3 illustrates a second forming operation 300 on the obtained ring structure, in accordance with some embodiments of the present disclosure. In FIG. 3, a second forming operation performed on the ring/hoop, subjected to the first forming operation as explained above with reference to FIG. 2, is shown. Referring to FIG. 3, a second forming operation forms a second axial side of the ring in an inward direction 302 to achieve a second conical shape with a second angle B at the second axial side, such as the upper side as shown in the exemplary illustration of FIG. 3. Simultaneously, the first angle A1 of the first cone can be increased to angle A2. In an aspect, the angle A2 can be same as angle in the finished disc, meaning thereby that no further forming of the fist cone shall be done in the third forming operation, Thus, an inner surface of the first cone formed during the second forming operation can be used as guiding surface for the die or the punch, as the case may be, during the third forming operation, which can ensure concentric seating of the part for the third forming operation.
[0038] The second operation is performed such that the second conical shape has a larger cone angle B than a cone angle A2 of the further enlarged first conical shape. In an aspect, forming the two sides to different angles reduces the formation of waves/zig-zags on inner surface of the ring.
[0039] In yet another aspect, increasing the diameter of the ring during the first and the second forming operations helps to check robustness of the welding done on the adjacent ends of the band to form the ring. Any flaw in the welding shall result in opening up of the joint due to extreme stresses due to the enlargement of diameter of the ring during the first and the second forming operations. Thus the proposed method also works as an indirect quality check on the weld joint.
[0040] FIG. 4 illustrates a third forming operation 400 on the obtained ring structure, in accordance with some embodiments of the present disclosure. In FIG. 4, a third forming operation performed on the ring/hoop, subjected to the first and second forming operations as explained above with reference to FIGs. 2 and 3, is shown. Referring to FIG. 4 the third forming operation further forms the second conical shape to achieve a flat surface 402 that is perpendicular to an axis of the ring, thereby achieving a required shape of the wheel disc. In some embodiments, the inward bent side is further bent inwards for example, at an angle of 90 degrees with respect to the initial position to form the desired shape of the disc.
[0041] It is to be appreciated that though the first forming operation, the second forming operation and the third forming operation have been described with reference to FIGs. 2, 3 and 4, where the first axial side is shown to be the lower side, it is not be linked in any manner to which of the two sides shall be positioned in the corresponding die while the other side is being formed by the corresponding punch. Any of the first forming operation, the second forming operation and the third forming operation can be done by positioning any of the first side and the second side in the corresponding die, while forming the other side by the corresponding punch.
[0042] Accordingly, FIG. 5 illustrates possible variations 500 in the process of performing the first, the second, and the third forming operations to manufacture the wheel disc, in accordance with some embodiments of the present disclosure. As shown therein, there can be eight different variations 500 in the process of performing the first, second and third forming operations, by different combinations of manner of positioning the first side or the second side in the corresponding die, while forming the other side by the corresponding punch.
[0043] FIG. 6 illustrates one or more operations 600 performed on a formed disc, i.e., after the first, the second, and the third forming operations, to achieve a final disc, in accordance with some embodiments of the present disclosure. In FIG. 6, an all-hole piercing (AHP) operation 602, flow forming 604, and the final wheel disc 606 are shown. In some embodiments the operations performed on the formed disc include flattening, face machining, AHP, flow forming, vent holes piercing (VHP), vent holes coining (VHC), spoke & bore machining and bolt hole drilling to achieve the final disc. In some other embodiments, the operations performed on the formed disc can include face machining, flow forming, bolt holes piercing (BHP), bolt holes coining (BHC), flattening, vent holes piercing (VHP), vent holes coining (VHC), and spoke & bore machining to achieve the final disc. The operations are explained below with reference to FIG. 7 and FIG. 8.
[0044] FIG. 7 illustrates a first variation 700 associated with the one or more operations 600 performed on a preformed disc to achieve a final disc, in accordance with some embodiments of the present disclosure. In FIG. 7, operations performed on the preformed disc such as, flattening 702, face machining 704, AHP 706, flow forming 708, vent holes piercing (VHP) 710, vent holes coining (VHC) 712, spoke & bore machining 714 and bolt hole drilling (716) to achieve the final disc 718, in accordance with some embodiments are shown. In some embodiments, the flattening 702 and face machining 704 may be made optional or removed from the set of operations to be performed on the preformed disc to achieve the final wheel disc 718.
[0045] FIG. 8 illustrates a second variation 800 associated with the one or more operations performed on a preformed disc to achieve a final disc, in accordance with some embodiments of the present disclosure. In FIG. 8, operations performed on the preformed disc such as face machining 802, flow forming 804, bolt holes piercing (BHP) 806, bolt holes coining (BHC) 808, flattening 810, vent holes piercing (VHP) 812, vent holes coining (VHC) 814, and spoke & bore machining 816 to achieve the final disc 818 in accordance with some other embodiments are shown. In some embodiments, face machining operation 802 may be made optional or may be removed from the set of operations to be performed on the preformed disc to achieve the final wheel disc 818.
[0046] FIG. 9 illustrates an exemplary flow diagram for the method 900 for manufacturing of the wheel disc, in accordance with some embodiments of the present disclosure. As shown therein, the method 900 for manufacturing of the wheel disc from a steel strip can include at step 902 of providing a metallic strip. Further, the method 900 may include, at step 904, a coiling process, to form a band from the metallic strip. The method 900 further includes at step 906 of welding both ends of the band to obtain a ring/hoop structure. In some embodiments, the welding operation may include a butt-welding operation.
[0047] The method 900 may further include, at step 908, re-rounding the ring/hoop structure. The re-rounding enables removing any oval shape change created due to the welding operation at step 906. The re-rounded ring/hoop is then subjected to expansion. The method 900 may include at step 910 an expansion or heating operation to expand the ring/hoop. The expansion operation enables achieving the required diameter for the ring for the subsequent forming operations.
[0048] Referring back to FIG. 9, upon expanding the ring/hoop, the method 900 may further include at step 912 performing forming operations on the expanded ring/hoop to obtain a preformed wheel disc. The preformed wheel disc is subjected to further operations to achieve the final wheel disc. The different forming operations and their respective variations were discussed in detail above with reference to FIGs. 2, 3, 4, and 5 and therefore are not included here for the sake of brevity.
[0049] Referring to FIG. 9, the method 900 may include, at step 914, the set of operations to be performed on the preformed disc, wherein the set of operations include AHP and flow forming to achieve the final disc. The set of operations on the preformed disc and their variations were discussed in detail above and therefore are not included here for the sake of brevity.
[0050] While the foregoing describes various embodiments of the invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof. The scope of the invention is determined by the claims that follow. The invention is not limited to the described embodiments, versions or examples, which are included to enable a person having ordinary skill in the art to make and use the invention when combined with information and knowledge available to the person having ordinary skill in the art.

ADVANTAGES OF THE DISCLOSURE
[0051] The present disclosure provides an improved method for manufacturing a disc wheel which ensures concentric seating of the ring on the die.
[0052] The present disclosure provides an improved method for manufacturing a disc wheel that reduces the waves or zigzags formed on an inner surface of the ring.
[0053] The present disclosure provides a method for manufacturing a disc wheel that passively works as a quality control check of butt welding on the part.
[0054] The present disclosure provides an improved method for manufacturing a disc wheel that reduces material wastage in the process of manufacturing the wheel disc.
[0055] The present disclosure provides an improved method for manufacturing a disc wheel that increase the thickness at the attachment area/nave contact area without hot forming.
[0056] The present disclosure provides an improved method for manufacturing a disc wheel that prepare the band with enough volume of material to address the required thickness at each location.
[0057] The present disclosure provides an improved method for manufacturing a disc wheel that achieve the circularity of the component by expanding process.
, Claims:1. A method for manufacturing a wheel disc, comprising:
providing a rectangular strip made of a metallic material;
rolling the rectangular strip to form a band;
welding adjacent ends of the band to form a ring;
expanding the formed ring to achieve a required diameter; and
forming the expanded ring to achieve a required shape of the wheel disc,
wherein the forming comprises:
a first forming operation to flare a first axial side of the ring in an outward direction to achieve a first conical shape at the first axial side, the first conical shape having a first angle;
a second forming operation to form a second axial side of the ring in an inward direction to achieve a second conical shape at the second axial side, and simultaneously forming the first axial side to increase the first angle of the first conical shape; and
a third forming operation to further form the second conical shape to achieve a flat surface that is perpendicular to an axis of the ring, thereby achieving a required shape of the wheel disc.

2. The method as claimed in claim 1, comprising:
forming the second axial side during the second forming operation to achieve the second conical shape that has a larger cone angle than the first angle of the first conical shape achieved during the second forming operation.

3. The method as claimed in claim 1, comprising:
performing one or more of the following steps on the achieved shape of wheel disc to obtain a final wheel disc:
piercing all holes;
performing flow forming;
piercing and coining of vent holes;
piercing and coining of bolt holes;
spoking and boring; and
bolt hole drilling.

4. The method as claimed in claim 1, comprising, during the second forming operation and the third forming operation, resting an inner surface of the first conical shape against a respective die of a matching shape.