Description:TECHNICAL FIELD
[0001] The present invention relates to the field of transmission systems. More particularly, the present disclosure relates to an improved, time-efficient, and cost-effective method of manufacturing shifter sleeves.

BACKGROUND
[0002] Transmission gears are integral components in various mechanical systems, such as transmission assemblies used in different applications, and other industrial machinery. They are responsible for maintaining the required speed ratios, ensuring smooth power transfer, and controlling the speed of the driven components. The shifter sleeve, as a vital part of transmission assemblies, facilitates in selection and engaging of gears, which directly impacts the efficiency, reliability, and overall performance of the transmission system.
[0003] The formation of teeth on the shifter sleeve significantly influences the performance of transmission gears. The accuracy and precision of the gear teeth directly impact the efficiency, reliability, and smooth operation of various mechanical systems, including automotive transmissions, and industrial machinery. Properly formed teeth ensure seamless engagement, reduce noise and vibration, and optimize power transmission, contributing to the overall performance and durability of the transmission gears. As the teeth play a crucial role in transmitting power and torque between components, achieving high-quality tooth geometry is imperative to ensure optimal gear functionality and the smooth operation of the mechanical systems they are integrated into.
[0004] Existing processes of manufacturing a shifter sleeve involve multiple steps. Initially, after forming rough spline teeth on the inner annular surface of a machine blank, roof angle and back taper are formed on the rough spline teeth using special Purpose Machine (SPM) chamfering, which is inefficient and time-consuming. However, in existing methods, creating the roof angle and back taper involves separate processes demanding considerable effort and time, rendering it inefficient in terms of cost. Further, the roof angle on the spline teeth of the shifter sleeve in all the existing art is formed by the axial force of the tool which is inefficient and time-consuming.
[0005] There is, therefore, a need for an improved manufacturing process for manufacturing shifter sleeves, which is both time-efficient and cost-effective.

OBJECTS OF THE PRESENT DISCLOSURE
[0006] Some of the objects of the present disclosure, which at least one embodiment herein satisfy, are listed below.
[0007] An object of the present disclosure is to provide an improved, time-efficient, and cost-effective process for manufacturing shifter sleeves for transmission.
[0008] An object of the present disclosure is to provide a method of manufacturing shifter sleeves, which eliminates the need for multiple operations for forming the internal spline teeth, reducing production time and enhancing manufacturing productivity.
[0009] An object of the present disclosure is to provide a method of manufacturing shifter sleeves, which improves the accuracy of the formation of internal spline teeth.
[0010] An object of the present disclosure is to provide a method of manufacturing shifter sleeves, which helps extend the life of the tools involved.
[0011] An object of the present disclosure is to provide a method of manufacturing shifter sleeves in which accuracy for formation and sharpness of the formed internal spline tooth is high.

SUMMARY
[0012] Aspects of the present disclosure relate to an improved, time-efficient, and cost-effective method of manufacturing shifter sleeves.
[0013] According to an aspect, a method of manufacturing a shifter sleeve is disclosed. The method comprises the steps of forming a plurality of partial spline teeth on an inner curved surface of a machined blank having an annular profile, followed by carrying out one or more stamping operation on the machined blank using one or more tool inserts such that a pair of roof angles and a teeth back taper are formed on each tooth of the partial spline teeth of the corresponding blank to form the shifter sleeve.
[0014] In an aspect, the steps of preparing the machined blank comprise forming a raw blank with predefined dimensions out of a cylindrical material such as a pipe or a round bar, hot forging the raw blank to form a hot forged blank, carrying out an annealing operation on the hot forged blank by subjecting the hot forged blank to a first predefined temperature for a predefined period, followed by a controlled cooling to form an annealed blank, and carrying out a first machining operation on 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 aspect, the method further comprises the steps of carrying out a second machining operation on the shifter sleeve after the one or more stamping operation for smoothening edges of the spline teeth formed in the shifter sleeve.
[0016] In an aspect, the plurality of partial spline teeth is formed on the inner curved surface of the machined blank by one or more tools using one or more of a broaching process, a slotting process, and a gear shaping process.
[0017] In an aspect, the one or more stamping operation includes using the one or more tool inserts that are configured to enable simultaneous forming of the pair of roof angles and the teeth back taper on all the partial spline teeth in a single operation.
[0018] In an aspect, the one or more stamping operation includes using the one or more tool inserts that are configured to enable sequential forming of the pair of roof angles and the teeth back taper on all the partial spline teeth in different operations.
[0019] In an aspect, the one or more stamping operation includes using the one or more tool inserts that are configured to enable sequential forming of the pair of roof angles and/or the teeth back taper on a set of teeth among the plurality of partial spline teeth at a time in different operations.
[0020] In an aspect, the pair of roof angles have any of a concave profile, a convex profile, or a planar profile.
[0021] In an aspect, the teeth back taper have any of a curved profile, or a planar profile.
[0022] In an aspect, the pair of roof angles are oriented at different angles.
[0023] Various objects, features, aspects, and advantages of the inventive 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
[0024] 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.
[0025] 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.
[0026] FIG. 1 illustrates an exemplary flowchart of the proposed method of manufacturing a shifter sleeve for transmission, in accordance with an embodiment of the present disclosure.
[0027] FIG. 2A to 6A illustrate schematic representations depicting stepwise expansion of the shifter sleeve while implementing the proposed method of FIG. 1, in accordance with an embodiment of the present disclosure.
[0028] FIG. 6B illustrates a detailed representation of a spline tooth associated with the final manufactured shifter sleeve of FIG. 6A, in accordance with an embodiment of the present disclosure.
[0029] FIG. 7A to 7D illustrate schematic representations of different profiles of the roof angle and back taper associated with the spline tooth of the shifter sleeve, in accordance with an embodiment of the present disclosure.
[0030] FIG. 8A to 8C illustrate a schematic representation of the individual profile of different tool sets utilized for forming roof angles and back tapers on a single spline tooth, in accordance with an embodiment of the present disclosure.
[0031] FIG. 9 illustrates an exemplary representation depicting die and toolset where arrows show the direction of the force of the tool inserts from the center to outwards i.e. in radial direction during the stamping operation.

DETAILED DESCRIPTION
[0032] In the following description, for the purposes of explanation, various specific details are set forth in order to provide a thorough understanding of embodiments of the present disclosure. It will be apparent, however, that embodiments of the present disclosure may be practiced without these specific details. Several features described hereafter can each be used independently of one another or with any combination of other features. An individual feature may not address all of the problems discussed above or might address only some of the problems discussed above. Some of the problems discussed above might not be fully addressed by any of the features described herein.
[0033] The word “exemplary” and/or “demonstrative” is used herein to mean serving as an example, instance, or illustration. For the avoidance of doubt, the subject matter disclosed herein is not limited by such examples. In addition, any aspect or design described herein as “exemplary” and/or “demonstrative” is not necessarily to be construed as preferred or advantageous over other aspects or designs, nor is it meant to preclude equivalent exemplary structures and techniques known to those of ordinary skill in the art. Furthermore, to the extent that the terms “includes,” “has,” “contains,” and other similar words are used in either the detailed description or the claims, such terms are intended to be inclusive—in a manner similar to the term “comprising” as an open transition word—without precluding any additional or other elements.
[0034] Reference throughout this specification to “one embodiment” or “an embodiment” or “an instance” or “one instance” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.
[0035] 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, 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 “comprises” and/or “comprising,” 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. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.
[0036] The following is a detailed description of embodiments of the disclosure depicted in the accompanying drawings. The embodiments are in such details 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 disclosures as defined by the appended claims.
[0037] FIG. 1 illustrates an exemplary flowchart of method 100 for manufacturing the shifter sleeve for transmission is disclosed. FIGs. 2A to 6A illustrate schematic representations depicting the stepwise formation of the shifter sleeve is disclosed. Method 100 involves a series of operations, each serving a specific purpose in transforming the raw material into the final product (shifter sleeve).
[0038] In an embodiment, at step 102, method 100 may involve forming a raw blank with predefined dimensions out of a cylindrical material such a round bar or a pipe. Method 100 at step 104 may further involve hot forging the raw blank to form a hot forged blank having an annular profile with an outer curved profile and an inner curved profile, where the inner profile pertains to a region for the set of spline teeth associated with the final shifter sleeve design. Further, method 100 at step 106 may involve carrying out an annealing operation on the hot forged blank by subjecting the hot forged blank to a predefined temperature for a predefined period, followed by a controlled cooling to form an annealed blank. Further, method 100 at step 108 may involve carrying out a first machining operation or a Computer Numerical Control (CNC) machining operation on the annealed blank for removal of surface scale and decarburized layer from the surface of the annealed blank to form a machined blank W1 or W1’ as shown in FIGs. 2A and 2B.
[0039] In an embodiment, the machine blank W1 may be formed using a rough CNC turning operation from the cylindrical material or forged root. Further, the machine blank W1’ may be formed using a semi-turning CNC operation from the cylindrical material or forged root, such that an outer circumferential groove is formed on the machined blank W1’. While various embodiments and drawings have been described herein for the machined blank W1’ having a specific shape or design for the sake of brevity, however, machined blank of any other shape or design is also possible through machining in this invention, and all such embodiments are well within the scope of the present disclosure without any limitations.
[0040] Once the machined blank W1 or W1’ is ready, method 100 at step 110 may involve forming a plurality of partial spline teeth on an inner curved surface (or inner profile) of the machined blank W1 or W1’ to provide a material W2 or W2’ as shown in FIG. 3A and 3B. Later, method 100 may involve another step 112 of carrying out one or more stamping operation on the machined blank material W2 or W2’ using one or more tool inserts 802 to 806 shown in FIGs. 8A to 8C such that a pair of roof angles and teeth back taper are formed on each tooth of the partial spline teeth of the corresponding blank to form the shifter sleeve W4 or W4’ as shown in FIGs. 5A and 5B. In addition, method 100 may involve the step 114 of carrying out a second machining operation or CNC operation on the shifter sleeve W4 or W4’ for smoothening edges of the spline teeth formed in the final shifter sleeve W5 or W5’ as shown in FIGs. 6A and 6B.
[0041] In an embodiment, the plurality of partial spline teeth may be formed on the inner curved surface of the machined blank W1 or W1’ by one or more tools using one or more of a broaching process, a slotting process, and a gear shaping process.
[0042] Further, in the stamping operation, a force may be applied in a radial direction from the center of the machined blank toward the rim. In an example, in the step of the stamping operation, method 100 may involve forming the roof angle to the partial spline teeth as well as the back taper using one or more specially designed tool sets 802 to 806 (as shown in FIGs. 8A to 8C, which may move radially outwards from the center of the machine blank and apply force on the inner surface in the radial direction as shown in FIG. 9 to form the back taper and the roof angle of the spline teeth as shown in FIGs. 6A to 7D.
[0043] In an embodiment, the roof angles and the teeth back taper may be simultaneously formed on all the partial spline teeth in a single operation. However, in another embodiment, the roof angles and the teeth back taper may be sequentially formed on all the partial spline teeth one by one in different operations. Further, in some embodiments, the roof angles and the teeth back taper may be sequentially or simultaneously formed on a set of teeth among the overall partial spline teeth at a time in different operations.
[0044] In an embodiment, preparing the machined blank W1 or W1’ may involve slicing or forming a raw blank out of a cylindrical member or a round member (such as a pipe or a round bar) having a predetermined axial length and predetermined diameter based on the profile of the shifter sleeve. In an example, this operation prepares the basic workpiece for subsequent processing. In a non-limiting example, the suitable cylindrical material or round bar for the shifter sleeve may be selected from a group comprising any or a combination of steel, alloy steel, and carbon steel, but not limited to the like.
[0045] In an embodiment, preparing the machined blank W1 or W1’ may further involve performing hot forging on the raw blank to obtain the hot forged blank. In a non-limiting example, the raw blank may be subjected to hot forging, where it may be heated to a high temperature (e.g., 1200 degrees Celsius) and then molded into a desirable blank appropriate for the shifter sleeve. Temperature parameter of 1200 degrees Celsius is illustrative in essence and is by no means confined or restricted in any manner. Any temperature values that are well-known and within the purview of an individual possessing ordinary skill in the pertinent art can be suitably adjusted and employed for the purpose of performing the hot forging process.
[0046] In an embodiment, the hot forging may be performed without developing the spline teeth profile. In an example, developing a shape for the spline teeth, so it does not necessitate a specialized precision hot forging facility. This eliminates the repetitive costs associated with tool replacement, thereby eliminating the need for a substantial investment in tooling. Additionally, all essential teeth shapes are attainable through stamping operation, resulting in superior teeth accuracy and sharpness of the roof angle and back taper.
[0047] In an embodiment, preparing the machined blank W1 or W1’ may further involve annealing the forged blank using a heat treatment to transform the forged blank into a stress-relieved material. In an example, annealing the forged blank may involve a heat treatment and transforming it into a stress-relieved material. In an embodiment, the material obtained after rough hot forging undergoes annealing. Annealing is a heat treatment process used to enhance the properties of a material, particularly metals and alloys. In an example, annealing involves heating the material to a specific temperature and holding it at that temperature for a certain period, followed by controlled cooling. Performing annealing may relieve stress and provide improvement in material properties.
[0048] The annealed blank is the raw material or beginning point for the CNC turning or machining operation. This material, however, has a surface scale. Due to exposure to high temperatures in an oxidizing atmosphere, the surface layer of a material (typically steel or other carbon-containing alloys) loses some of its carbon content during decarburization. During thermal treatment or high-temperature processing of carbon-containing materials, this issue frequently arises.
[0049] In an embodiment, preparing the machined blank W1 or W1’ may further involve machining the stress-relieved (annealed) material by a first CNC turning operation to remove the decarburizing layer from the surface of the corresponding material. Machining the annealed blank by CNC turning helps in removing decarburizing (surface scale) and achieving the desired overall packaging dimensions. The result of this operation is the final machined blank W1 or W1’, in which the spline teeth may be later formed.
[0050] CNC turning operation is essential because the surface scale is often brittle and undesirable for most engineering applications. By removing this layer, the machined surface of the blank or final shifter sleeve may have improved mechanical properties and surface finish. In an example, the decarburizing layer removal during the CNC operation may be achieved by precision machining tools or CNC machines. Apart from removing the decarburized layer, the CNC turning operation also shapes the annealed blank to attain the required overall packaging dimensions. This involves cutting, shaping, and refining the workpiece to meet the precise specifications and tolerances.
[0051] In an embodiment, method 100 at step 110 may involve forming a plurality of partial spline teeth on an inner curved surface of the machined blank W1 or W1’ of FIGs. 2A and 2B have the annular profile to provide a material W2 or W2’ respectively as shown in FIGs. 3A and 3B. In an embodiment, the plurality of partial spline teeth may be formed on the inner curved surface of the machined blank W1 or W1’ by one or more tools using one or more of a broaching process, a slotting process, and a gear shaping process.
[0052] In an implementation, the broaching process involves using a toothed tool, known as a broach, which is pushed or pulled through the material of the machined blank W1 or W1’ to remove metal progressively. Each tooth on the broach is slightly larger than the previous one, which allows for gradual material removal and precise shaping of the spline teeth. Further, in the slotting process, a vertically reciprocating tool cut grooves or slots into the machined blank W1 or W1’, shaping the partial spline teeth. This process is similar to shaping but involves a vertical cutting motion. The tool removes material in repeated strokes, gradually forming the desired spline geometry. Furthermore, in the gear shaping process, a rotating cutting tool resembling the spline is used. The tool and the machine blank rotate in coordination, allowing the tool to gradually cut the spline teeth to the required depth and shape.
[0053] In an embodiment, method 100 at step 112 may involve carrying out one or more stamping operation on the material W2 or W2’ of FIG. 3B having the partial spline teeth using one or more tool inserts 802 to 806 as shown in FIGs. 8A to 8C such that a pair of roof angles and teeth back taper are formed on each tooth of the partial spline teeth of the corresponding blank to form the shifter sleeve W4 or W4’ respectively as shown in FIGs. 5A and 5B. Further, method 100 may involve the step 114 of carrying out a second CNC operation on the shifter sleeve W4 or W4’ for smoothening edges of the pair of roof angles 602-1, 602-2, and teeth back taper 604-1 604-2 formed in the finally formed shifter sleeve W5 or W5’ as shown in FIGs. 6A and 6B.
[0054] In an embodiment, dies and tool inserts 802 to 806 being used in the stamping process may have the negative impression of the spline tooth’s geometry. When the tool insert(s) 802 to 806 exerts pressure on the partial spline teeth in radially outward direction from center of the blank, the surface or edges of the partial spline teeth may undergo deformation, which changes its shape to form a pair of roof angles 602-1, 602-2 and/or teeth back taper 604-1 604-2 of desired profile (as shown in FIGs. 6A to 7D) without altering its composition.
[0055] Referring to FIG. 7A, in an embodiment, the pair of roof angles 602-1, 602-2 and back taper 604-1 604-2 associated with the spline teeth of shifter sleeve W5 or W5’ may have a planar profile. Further, referring to FIG. 7B, in an embodiment, the roof angles 602-1, 602-2 and back taper 604-1 604-2 associated with the spline teeth of shifter sleeve W5 or W5’ may have a curved profile. In an example, as illustrated, the pair of roof angles 602-1, 602-2 may have a concave profile, and the back taper 604-1, 604-2 may have a convex profile. Furthermore, referring to FIG. 7C, in an embodiment, the pair of roof angles 602-1, 602-2 associated with the spline teeth of shifter sleeve W5 or W5’ may be oriented at different angles, while having a planar or curved profile. Furthermore, referring to FIG. 7C, in an embodiment, the pair of roof angles 602-1, 602-2 associated with the spline teeth of shifter sleeve W5 or W5’ may have a convex profile, and the back taper 604-1, 604-2 may have a planar profile. Similarly, the pair of roof angles 602-1, 602-2 and the back taper 604-1, 604-2 associated with the spline teeth may have any or a combination of a planar profile and a curved profile without any limitation, and all such embodiments are well within the scope of the present disclosure.
[0056] Referring to FIGs. 6A and 6B, in an embodiment, at this step 112, a single stamping operation may be performed on the material W2 or W2’ having the partial spline teeth using the tool set 806 of FIG. 8C to simultaneously create a pair of roof angles, such as left roof angle 602-1 and right roof angle 602-2, and back taper 604-1, 604-2 on each spline teeth, to provide the final shifter sleeve W5 or W5’.
[0057] In an alternate embodiment, method 100 at step 112 may involve forming the pair of roof angles 602-1, 602-2 and the back taper 604-1, 604-2 of the spline teeth in separate stamping operations. However, forming the roof angle 602-1, 602-2 and the back taper 604-1, 604-2 of the spline teeth is preferred as it results in shifter sleeves with highly accurate spline teeth. Referring to FIGs. 4A and 4B, in an embodiment, at step 112, a stamping operation may be performed on the material W2 or W2’ (having the partial spline teeth) using the tool set 802 of FIG. 8A to first create a pair of roof angles 602-1, 602-2 to provide the material W3 or W3’ respectively. Further, referring to FIGs. 5A and 5B, in an embodiment another stamping operation may be performed on the material W3 or W3’ (having the roof angles) using the tool set 804 of FIG. 8B to create the back taper 604-1, 604-2 to provide the material W4 or W4’ respectively. However, the back taper 604-1, 604-2 may also be formed before forming the roof angles 602-1, 602-2.
[0058] In yet another embodiment, method 100 at step 112 may involve forming the pair of roof angles 602-1, 602-2 and the teeth back taper 604-1, 604-2, either sequentially or simultaneously, on a set of teeth among the overall partial spline teeth at a time in different operations. For instance, in a non-limiting example, the roof angles 602-1, 602-2 and the teeth back taper 604-1, 604-2 may be first formed on 15 partial spline teeth among a total of 30 partial spline teeth in one stamping operation, followed by forming the roof angles 602-1, 602-2 and the teeth back taper 604-1, 604-2 of remaining partial spline teeth further stamping operation(s).
[0059] Accordingly, the stamping operations for forming roof angles 602-1, 602-2 and the back tape 604-1, 604-2, either singly/individually or together, i.e., in combination with the other, may be performed using a die set having tool sets 802 and 804 or a single tool set 806 which apply stamping force in a radially outward direction, as shown in FIG. 9, to enable development of the roof angle and the back taper of the spline teeth.
[0060] FIG. 8A illustrates a schematic representation of the individual profile of the tool set 802 which is used to generate the roof angle 602-1, 602-2 on a single tooth. FIG. 8B illustrates a schematic representation of the individual profile of the tool set 804 which is used to generate the back taper 604-1, 604-2 on a single tooth. FIG. 8C illustrates a schematic representation of the individual profile of the tool set 806 which is used to simultaneously generate both the roof angles 602-1, 602-2 and the back taper 604-1, 604-2 on a single tooth.
[0061] Referring to FIG. 9, during the stamping operation, a radial force may be uniformly applied in a 360˚ manner. The applied radial force may be applied by the individual tool sets for each spline tooth or all spline teeth at a time or a set of spline teeth at a time, which may simultaneously move radially outward from the center of the blank, exerting the necessary force on the respective spline tooth to bring about material deformation to generate the required profile having the desired roof angles and the back taper.
[0062] In an implementation, the die set can include multiple tool sets for forming the roof angles and the back tapers, one tool for each of the plurality of splines. Each of the tool sets can simultaneously move radially inward to provide the roof angles and the back tapers to each spline tooth or all spline teeth at a time or a set of spline teeth at a time in one or more stamping operations. In an alternate application, the die set can include one or more tool sets, but less than the number of splines, and the blank can be indexed by rotation to align each of the splines with the tools and thereafter the tools can be moved radially outwards to form the roof angles and the back tapers on the corresponding splines.
[0063] Further, in conventional methods, the roof angle is typically formed by applying axial force using tools. The present disclosure provides a technical advantage by employing radial force, ensuring precise and efficient results. By exerting pressure uniformly from all directions, the tool ensures consistency in shaping the teeth' roof angle. This leads to a uniform tooth profile on the material, elevating the overall quality and functionality of the manufactured components. Furthermore, the use of radial force reduces the risk of irregular or distorted tooth formations often associated with axial force methods. Moreover, carrying out a second machining operation or CNC operation on the shifter sleeve after the stamping operation may help smooth the edges of the spline teeth formed in the finally formed shifter sleeve. The heightened precision not only meets rigorous quality standards but also enhances the performance and longevity of the end product.
[0064] Consequently, the above-described method 100 of manufacturing shifter sleeves involves stamping operations, which simultaneously or sequentially develops roof angle and back taper geometries on spline teeth. By integrating these operations, the process achieves precise tooth profiles and enhances overall productivity. This innovative approach eliminates the need for separate manufacturing steps, leading to higher accuracy in tooth formation and a more efficient production process. Further, by exerting radial force uniformly in radially outward directions, the tool guarantees consistency in shaping the teeth' roof angle and back taper. As a result, the shifter sleeves for transmission produced through this method exhibit improved teeth accuracy and present a highly productive manufacturing solution.
[0065] 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 INVENTION
[0066] The present invention provides an improved, time-efficient, and cost-effective process for manufacturing shifter sleeves for transmission.
[0067] The present invention provides a method of manufacturing shifter sleeves, which eliminates the need for multiple operations for forming the internal spline teeth, reducing production time and enhancing manufacturing productivity.
[0068] The present invention provides a method of manufacturing shifter sleeves, which improves the accuracy of the formation of internal spline teeth.
[0069] The present invention provides a method of manufacturing shifter sleeves, which helps extend the life of the tools involved.
[0070] The present invention provides a method of manufacturing shifter sleeves in which the accuracy for the formation and sharpness of the formed internal spline tooth is high.
.
, Claims:1. A method (100) of manufacturing a shifter sleeve, the method (100) comprising:
forming (110) a plurality of partial spline teeth on an inner curved surface of a machined blank having an annular profile; and
carrying (112) out one or more stamping operation on the machined blank using one or more tool inserts such that a pair of roof angles and a teeth back taper are formed on each tooth of the partial spline teeth of the corresponding blank to form the shifter sleeve.
2. The method (100) as claimed in claim 1, wherein the steps of preparing the machined blank comprises:
forming (102) a raw blank with predefined dimensions out of a cylindrical material including a pipe or a round rod;
hot forging (104) the raw blank to form a hot forged blank;
carrying out an annealing operation (106) on the hot forged blank by subjecting the hot forged blank to a first predefined temperature for a predefined period, followed by a controlled cooling to form an annealed blank; and
carrying out a first machining operation (108) on the annealed blank for removal of surface scale and decarburized layer from surface of the annealed blank to form the machined blank.
3. The method (100) as claimed in claim 1, wherein the method (100) further comprises the steps of:
carrying out a second machining operation (114) on the shifter sleeve after the one or more stamping operation for smoothening edges of the spline teeth formed in the shifter sleeve.
4. The method (100) as claimed in claim 1, wherein the plurality of partial spline teeth are formed on the inner curved surface of the machined blank by one or more tools using one or more of a broaching process, a slotting process, and a gear shaping process.

5. The method (100) as claimed in claim 1, wherein the one or more stamping operation includes using the one or more tool inserts that are configured enable simultaneous forming of the pair of roof angles and the teeth back taper on all the partial spline teeth in a single operation.
6. The method (100) as claimed in claim 1, wherein the one or more stamping operation includes using the one or more tool inserts that are configured to enable sequential forming of the pair of roof angles and the teeth back taper on all the partial spline teeth in different operations.
7. The method (100) as claimed in claim 1, wherein the one or more stamping operation includes using the one or more tool inserts that are configured to enable sequential forming of the pair of roof angles and/or the teeth back taper on a set of teeth among the plurality of partial spline teeth at a time in different operations.
8. The method (100) as claimed in claim 1, wherein the pair of roof angles have any of a concave profile, a convex profile, or a planar profile.
9. The method (100) as claimed in claim 1, wherein the teeth back taper have any of a curved profile, or a planar profile.
10. The method (100) as claimed in claim 1, wherein the pair of roof angles are oriented at different angles.