DESC:TECHNICAL FIELD
[0001] The present invention relates to the field of manufacturing of transmission systems. More particularly, the present invention relates to a method for manufacturing clutch body (CB) ring.

BACKGROUND
[0002] CB rings are crucial components in various mechanical systems, serving as integral parts of transmission assemblies used across a range of applications and other industrial machinery. Their primary function is to maintain the required gear ratios, ensuring the smooth transfer of power and precise control over the speed of driven components. CB ring in transmission assemblies, play a pivotal role in facilitating the engagement and interaction of gear teeth. This engagement directly influences the efficiency, reliability, and overall performance of the transmission system.
[0003] The formation of teeth on CB rings involves a complex manufacturing process, exerting a significant impact on the performance of these essential components. The accuracy and precision of the gear teeth have a direct bearing on the efficiency, reliability, and smooth operation of various mechanical systems, including automotive transmissions and industrial machinery. Properly formed teeth during the manufacturing process are instrumental in ensuring seamless engagement, reducing noise and vibration, and optimizing power transmission. These factors collectively contribute to the overall performance and durability of CB rings. As the teeth are central to transmitting power and torque between components, attaining high-quality tooth geometry becomes imperative to guarantee the optimal functionality and smooth operation of the mechanical systems where CB rings are integrated.
[0004] The process of forming teeth on CB rings involves several steps. Initially, following the first hot forging process of blanking, the second hot forging procedure shapes straight splines and establishes a rough roof angle on the dog teeth. Subsequently, the finished roof angle of the teeth is meticulously achieved through cold forging. Another cold forging operation is employed to produce the tooth back taper. Finally, the gear teeth are expertly formed during the gear-cutting process. However, in the current state of the art, the roof angle and back taper are generated through separate processes.
[0005] There is, therefore, a need for a manufacturing process that form both the important profiles of the teeth i.e., roof angle and back taper are formed in single cold forging operation.

OBJECTS OF THE PRESENT DISCLOSURE
[0006] An object of the present disclosure is to overcome the existing problems associated with the manufacture of transmission systems and provide a method for manufacturing clutch body (CB) ring;
[0007] Another object of the present disclosure is to provide a method for manufacturing the clutch body (CB) ring where partial spline teeth are formed initially on a machined blank;
[0008] Yet another object of the present disclosure is to provide a method for manufacturing the clutch body (CB) ring where a pair of roof angles and a teeth back taper are forged on each tooth of the partial spline teeth of the machined blank in a single forging operation;
[0009] Yet another object of the present disclosure is to provide a solution for manufacturing the CB ring that is cost-effective.
[0010] Yet another object of the present disclosure is to provide a solution for manufacturing CB ring that have extended tool life.

SUMMARY
[0011] Aspects of the present disclosure relates to the field of manufacturing of transmission systems. More particularly, the present disclosure relates to a method for manufacturing clutch body (CB) ring.
[0012] In an aspect, a method for forming a clutch body (CB) ring includes a step of preparing a machined blank for carrying out a first cold forging operation on the machined blank. The machined blank is compressed within a cavity of a die for forming a partial spline teeth on the machined blank during the first cold forging operation. Further, the method includes a step of carrying out a second cold forging operation on the first cold forged blank. A pair of roof angles and a teeth back taper are forged on each tooth of the partial spline teeth of the first cold forged blank to form a second cold forged blank.
[0013] In an embodiment, the method may include a step of heat treating the second cold-forged blank. The second cold-forged blank may be subjected to a controlled heating and cooling to form a final blank.
[0014] In an embodiment, the preparation of the machined blank before first cold forging operation may include a step of slicing a raw blank with predefined dimensions out of a cylindrical material. The sliced raw blank may be subjected to hot forging at an elevated temperature, such as at a temperature of about 1200 degrees Celsius, to form a hot forged blank. The preparation of the machined blank in addition may include a step of carrying out a first annealing operation on the hot forged blank by heating the hot forged blank to a first predefined temperature for a predefined period. Thereafter, the hot forged blank may be subjected to controlled cooling to form a first annealed blank. The preparation of the machined blank in addition may include a machining of the annealed blank for removal of surface scale and decarburized layer from the surface of the annealed blank to form the machined blank.
[0015] In an embodiment, the mold cavity may include teeth geometry for forming a tooth profile on the machined blank upon being subjected to cold forging.
[0016] In an embodiment, the pair of roof angles may include a left roof angle and a right roof angle. The left roof angle and the right roof angle may define finished teeth of the CB ring.
[0017] In an embodiment, the step of heat treating may include subsequent steps of performing a second annealing on the second cold-forged blank. The second cold-forged blank may be heated to a second predefined temperature from which, the second cold-forged blank may be slowly cooled to form a second annealed blank. The subsequent steps in addition may include a step of hardening the second annealed blank to form a hardened blank. The subsequent steps may further include a step of tempering the hardened blank. The hardened blank may be reheated at a lower temperature in the step of tempering.
[0018] In an embodiment, the final blank formed upon the heat treating may be subjected to hard finishing. The said hard finishing may include honing of a bore of the CB ring.
[0019] Various objects, features, aspects, and advantages of the subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.

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, explain the principles of the present disclosure. The diagrams are for illustration only, which thus is not a limitation of the present disclosure.
[0021] Similar components and/or features may have the same reference label in the figures. Further, various components of the same type may be distinguished by following the reference label with a second label that distinguishes among the similar components. Suppose only the first reference label is used in the specification. In that case, the description applies to any similar components with the same first reference label, irrespective of the second reference label.
[0022] FIG. 1 illustrates an exemplary flowchart of a method for manufacturing a CB ring, in accordance with an embodiment of the present disclosure.
[0023] 2A- 2G illustrates a schematic representation of stepwise expansion of a CB ring, in accordance with an embodiment of the present disclosure.

DETAILED DESCRIPTION
[0024] 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 spirit, and scope of the present disclosure as defined by the appended claims.
[0025] In the following description, numerous specific details are set forth in order to provide a thorough understanding of 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.
[0026] If the specification states a component or feature "may", "can", "could", or "might" be included or have a characteristic, that particular component or feature is not required to be included or have the characteristic.
[0027] As used in the description herein and throughout the claims that follow, the meaning of "a", "an", and "the" includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of "in" includes "in" and "on" unless the context clearly dictates otherwise.
[0028] According to an aspect, a method for forming a clutch body (CB) ring is disclosed, where a machined blank is prepared for undergoing a series of operations. A first cold forging operation is carried on the machined blank. Where the machined blank is compressed within a cavity of a die for forming a partial spline teeth on the machined blank. Further, a second cold forging operation is carried out on the first cold forged blank such that a pair of roof angles and a teeth back taper are forged on each tooth of the partial spline teeth of the first cold forged blank to form a second cold forged blank in a single operation. The method achieves precise tooth profiles and enhances overall productivity, eliminating the need for separate manufacturing steps, and leading to higher accuracy in tooth formation and a more efficient production process. As a result, the CB ring for transmission produced through the said method exhibits improved teeth accuracy and represents a highly productive manufacturing solution.
[0029] FIG. 1 illustrates an exemplary flowchart of a method for forming a clutch body (CB) ring, in accordance with an embodiment of the present disclosure. FIG. 2A- 2G illustrates a schematic representation of stepwise expansion of a clutch body ring, in accordance with an embodiment of the present disclosure. Referring to FIG. 1 and FIG. 2A-2G, the method 100 involves a series of operations, each serving a specific purpose in transforming the raw blank into the final finished blank.
[0030] As illustrated, at step 102, the method 100 can involve slicing 102 a cylindrical material to obtain a suitable material (hereinafter referred to as “raw bank W1”) with predefined dimensions as shown in FIG. 2A. In a non-limiting example, the method 100 for manufacturing the clutch body (CB) ring may involve cutting a raw blank W1 having an axial length out of a cylindrical material appropriate for use in transmission systems. In an example, this operation can be the basic work piece or a raw blank W1 suitable for subsequent processing.
[0031] As illustrated, in step 104, the method 100 can involve a step of subjecting the raw blank W1 to hot forging 104 to form hot forged blank W2 as shown in FIG. 2B. In a non-limiting example, the method 100 may involve, subjecting the raw blank W1 as shown in FIG. 2A to hot forging 104, where the raw blank W1 can be heated to a temperature of 1200 degrees Celsius and then molded into a desirable blank suitable for transmission gear. A specialized precision hot forging facility may not be required for said method 100 as the teeth are not shaped during the hot forging 104 such that the costs associated with tool replacement can be eliminated. Additionally, all essential teeth shapes formed through cold forging can result in superior teeth accuracy and sharpness of the roof angle 202.
[0032] As illustrated, at step 106, the method 100 can involve a first annealing 106 operation on the hot forged blank W2 after the hot forging 104 to form a first annealed blank W3 as shown in FIG. 2C. In an embodiment, the method 100 may involve first annealing 106 operation on the hot forged blank W2 after rough hot forging 104. The first annealing 106 operation can be a heat treatment process used to enhance the properties of the hot forged blank W2. In an example, first annealing 106 operation can involve heating the hot forged blank W2 to a fixed temperature for a fixed period, followed by controlled cooling. The first annealing 106 operation of the hot forged blank W2 may enhance tension relief and material property enhancement forming a first annealed blank W3.
[0033] In the example, the first annealed blank W3 ready blank for a CNC turning operation can be subjected to decarburization where the surface scale of the first annealed blank W3 may be removed from the surface of the first annealed blank W3 when exposed to high temperatures in an oxidizing atmosphere. The first annealed blank W3 (typically steel or other carbon-containing alloys) can lose some of its carbon content during decarburization. During thermal treatment or high-temperature processing of carbon-containing materials, said issue of decarburization arises frequently.
[0034] As illustrated, at step 108, the method involves machining the first annealed blank W3 by CNC turning without decarburizing (surface scale) to achieve the desired overall dimensions and form a machined blank W4 as shown in FIG. 2D. In a non-limiting example, machining the first annealed blank W3 as shown in FIG. 2C by CNC turning prevents the removal of decarburizing (surface scale) and achieves the desired overall packaging dimensions forming the machined blank W4. The machining 108 operation uses a CNC turning machine for removal of the surface scale (decarburized layer) from the first annealed blank W3. The surface scale of the first annealed blank W3 may be brittle and undesirable for most engineering applications. The CNC turning machine can be configured for decarburization such that the mechanical properties and surface finish can be improved. Apart from preventing the removal of the decarburized layer. The CNC turning operation can shapes the first annealed blank W3 to attain the required overall packaging dimensions. This involves cutting, shaping, and refining the first annealed blank W3 to meet the precise specifications and tolerances.
[0035] As illustrated, at step 110, the method 100 can involve a step of subjecting the machined blank W4 to a first cold forging 110 operation for the formation of straight spline teeth on a CB ring to form first cold forged blank W5 as shown in FIG. 2E.
[0036] In a non-limiting example, machined blank W4 can be subjected to the first cold forging 110 operation after the machining. The first cold forging 110 operation can be a metal forming process that occurs at room temperature or slightly elevated temperatures, typically below the recrystallization temperature of the material. During this step, the machined blank W4, may be subjected to compressive forces within specialized dies and molds. The pressure applied causes the machined blank W4 to flow and take the shape of the dies, resulting in the formation of straight spline teeth on CB ring to form first cold forged blank W5, as shown in FIG. 2E. In this step, the machined blank W4 may be shaped to form straight spline teeth and form the first cold forged blank W5.
[0037] In an example, first cold forging at step 102, may be employed to shape the machined blank W4 into the desired tooth profile. The dies used in the process may have the negative impression of the tooth geometry. When the machined blank W4 is inserted between the dies and subjected to pressure, it undergoes deformation, which permanently changes its shape without altering its chemical composition.
[0038] As illustrated, at step 112, the method 100 can include a step of second cold forging 112 operation to develop finished teeth with the desired shape and form the second cold-forged blank W6 as shown in FIG. 2F
[0039] In an embodiment, at step 112, the first cold forged blank W5 as shown in FIG. 2E, where a straight spline teeth are being formed upon the second cold forging 112 operation with desired shape. The second cold forging 112 operation can be a single operation creating a pair of roof angles 202, such as left roof angle 202-1 and right roof angle 202-2 (collectively and individually refereed as roof angles/roof angle 202, herein), on each tooth, as well as the teeth back taper 204.
[0040] In an example, forming a pair of roof angles 202 (a right roof angle 202-2 and a left roof angle 202-4) and a teeth back taper 204 can eliminate the need for separate forging steps and prevent errors or deviations that could occur while carrying out the profiles individually. As a result, the precision and accuracy of the teeth, are significantly improved as shown in the second cold forged blank W6 in FIG.2F. Additionally, the combined cold forging process leads to higher productivity as it reduces the overall number of manufacturing steps and simplifies the production flow. This increased efficiency allows for more gear components to be produced in a shorter time frame, resulting in a rise in overall production output. The synergy of enhanced precision and improved productivity makes the manufacturing process more cost-effective and yields high-quality transmission gears with reliable performance characteristics.
[0041] As illustrated, at step 114, the method involves heat treating 114 the second cold forged blank W6 to achieve the desired hardness and improve its mechanical properties and form a final blank W7 as shown in FIG. 2G.
[0042] In an embodiment, at step 114, the second cold-forged blank W6 may undergo heat treatment 112 to achieve the desired hardness and improve its mechanical properties. The heat treatment 112 operation can be a controlled heating and cooling process that can be applied to the second cold-forged blank W6 to achieve specific mechanical properties and improve its overall performance. In example, during heat treatment 112, the CB ring is subjected to carefully controlled temperatures for a predetermined period. This process allows for the transformation of the material's microstructure, which affects its hardness, strength, toughness, and other mechanical properties. The heat treatment 112 can aim to achieve the desired balance of these properties, making the CB ring efficient for transmission.
[0043] In an example, heat treatment 112 may include but not limited to second annealing 114A, hardening 114B, and tempering 114C. The method 100 may involve second annealing 114A that involves heating the second cold-forged blank W6 to a specific temperature and then slowly cooling it, to reduce internal stresses and increase ductility. In an example, the method 100 may involve hardening 114B where the cold-forged blank W6 is rapidly cooled to achieve a higher hardness, making it more wear-resistant to from a hardened blank. In an example, the method 100 may involve tempering 114C. After hardening 114B, the hardened blank can be reheated to a lower temperature to reduce brittleness and increase toughness to form a final blank W7.
[0044] In an embodiment, the method of manufacturing CB ring may further involve, at step 114, hard finishing of the material W6 to obtain W7 as shown in 2G. In an exemplary embodiment, hard finishing of the material may include but may not be limited to honing the through bore 108 of the CB ring, resulting into a final finished blank W7.
[0045] In an example, the hard finishing may involve honing the through bore of the CB ring. Honing is a process that refines the internal surface of the bore to achieve superior dimensional accuracy, surface finish, and straightness. This step ensures that the bore meets tight tolerances and is ready to accommodate components that fit with the CB ring.
[0046] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, for example, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "contains", "containing", "includes", "including," "comprises", and/or "comprising," and variations thereof, when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
[0047] Terms of orientation are used herein merely for purposes of convention and referencing and are not to be construed as limiting. However, it is recognized these terms could be used with reference to an operator or user. Accordingly, no limitations are implied or to be inferred. Also, if used herein, the terms "coupled" or "coupled to" or "connected" or "connected to" or "attached" or "attached to" may indicate establishing either a direct or indirect connection, and are not limited to either unless expressly referenced as such.
[0048] While the disclosure has described several exemplary embodiments, it will be understood by those skilled in the art that various changes can be made, and equivalents can be substituted for elements thereof, without departing from the spirit and scope of the invention. In addition, many modifications will be appreciated by those skilled in the art to adapt a particular instrument, situation, or material to embodiments of the disclosure without departing from the essential scope thereof.
[0049] Therefore, it is intended that the invention not be limited to the particular embodiments disclosed, or to the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims. Moreover, reference in the appended claims to an apparatus or system or a component of an apparatus or system being adapted to, arranged to, capable of, configured to, enabled to, operable to, or operative to perform a particular function encompasses that apparatus, system, or component, whether or not it or that particular function is activated, turned on, or unlocked, as long as that apparatus, system, or component is so adapted, arranged, capable, configured, enabled, operable, or operative.
[0050] It may be noted that the above-described examples of the present solution are for the purpose of illustration only. Although the solution has been described in conjunction with a specific embodiment thereof, numerous modifications may be possible without materially departing from the teachings and advantages of the subject matter described herein. Other substitutions, modifications and changes may be made without departing from the spirit of the present solution. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

ADVANTAGES OF THE INVENTION
[0051] The present disclosure provides a method for manufacturing clutch body (CB) ring;
[0052] The present disclosure provides a method for manufacturing the clutch body (CB) ring where partial spline teeth are formed initially on a machined blank;
[0053] The present disclosure provides a method for manufacturing the clutch body (CB) ring where a pair of roof angles and a teeth back taper are forged on each tooth of the partial spline teeth of the machined blank in a single forging operation;
[0054] The present disclosure provides a solution for manufacturing the CB ring that is cost-effective.
[0055] The present disclosure provides a solution for manufacturing CB ring that have extended tool life.

CLAIMS:

1. A method for forming a clutch body (CB) ring, the method (100) comprising:
preparing a machined blank (W4); carrying out a first cold forging (110) operation on the machined blank (W4), wherein, during the first cold forging (110) operation the machined blank (W4) is compressed within a cavity of a die for forming a partial spline teeth on the machined blank (W4); and
carrying out a second cold forging (112) operation on the first cold forged blank (W5) such that a pair of roof angles (202) and a teeth back taper (204) are forged on each tooth of the partial spline teeth of the first cold forged blank (W5) to form a second cold forged blank (W6).

2. The method (100) as claimed in claim 1, comprising the step of heat treating (114), the second cold-forged blank (W6), where the second cold-forged blank (W6) is subjected to a controlled heating and cooling to form a final blank (W7).

3. The method (100) as claimed in claim 1, wherein the step of preparing a machined blank (W4); comprises:
slicing (102) a raw blank (W1) with predefined dimensions out of a cylindrical material;
hot forging (104) the sliced raw blank (W1) to form a hot forged blank (W2);
carrying out a first annealing (106) operation on the hot forged blank (W2) by subjecting the hot forged blank (W2) to a first predefined temperature for a predefined period, followed by a controlled cooling to form an first annealed blank (W3);
machining (108) the annealed blank (W3) for removal of surface scale and decarburized layer from surface of the annealed blank (W3), forming the machined blank (W4).

4. The method (100) as claimed in claim 1, wherein the mold cavity comprises teeth geometry for forming a tooth profile on the machined blank (W4) upon being subjected to cold forging.

5. The method (100) as claimed in claim 1, wherein the pair of roof angles (202) comprises a left roof angle (202-1) and a right roof angle (202-2), which define finished teeth of the CB ring.

6. The method (100) as claimed in claim 2, wherein the step of heat treating (114) comprises steps of:
performing a second annealing (114A) on the second cold-forged blank (W6), wherein said second cold-forged blank (W6) is heated to a second predefined temperature, followed by a slow cooling to form a second annealed blank;
hardening (114B) the second annealed blank to form a hardened blank; and
tempering (114C) the hardened blank where the hardened blank is reheated at a lower temperature.

7. The method (100) as claimed in claim 6, wherein the final blank (W7) formed upon the heat treating (114) is subjected to hard finishing, wherein said hard finishing comprises honing of a bore of the CB ring.