Method for forming a splined component

Abstract

A new method for manufacturing a torque transfer component is provided. The method includes providing a flat blank to a transfer press having multiple stations and performing multiple pressing operations. During the pressing operations, the flat blank is formed into a cup shape, rough splines are formed in the cup shape, and the rough splines are further pressed to define smooth splines. The component includes a continuous smooth inner diameter defined by a punch of the transfer press and a plurality of smooth splines defined by a die of the transfer press. The minor diameter of the splines is not machined to form the splines.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This PCT international patent application claims the benefit of previously filed U.S. Provisional Patent Application No. 62 / 978,096, filed on February 18, 2020, the entire contents of which are hereby incorporated by reference in their entirety. Technical Field

[0003] The present disclosure generally relates to a novel method for manufacturing a splined component and a splined component manufactured according to the novel method. More specifically, the present disclosure relates to a component manufactured using a draw forming process, a roller die spline forming process, and a coining operation, all of which can be sequentially arranged in a transfer press unit. Background Art

[0004] This section provides background information related to the present disclosure which is not necessarily prior art.

[0005] Power transfer devices of the type used in motor vehicle applications, such as automatic transmissions, torque couplings, power take-off units, and transfer cases, are typically equipped with a power-operated multi-plate clutch assembly. Typically, a multi-plate clutch assembly includes a first clutch member (such as a clutch hub) driven by an input component, a second clutch member (such as a clutch drum) that drives the output component, a multi-plate clutch pack disposed between the first and second clutch members, and a power clutch actuator for engaging the clutch pack and transferring drive torque from the clutch hub to the clutch drum. The clutch drum and clutch hub are typically annular components having torque-transmitting spline teeth configured to engage and mesh with corresponding clutch teeth formed on the clutch plates of the clutch pack.

[0006] In order to reduce the mass of such clutch components while maintaining the required high strength and torque transmission characteristics, many modern clutch hubs and drums, hereinafter collectively referred to as annular clutch components, are formed from sheet metal blanks using a combination of various metal forming and metal cutting processes. Non-limiting examples of high-volume processes currently used to manufacture annular clutch components include the Grob spline process and the flow forming process.

[0007] Due to the design of these formed metal plate clutch components, currently available processes also have several known shortcomings. Specifically, annular clutch components are initially formed from a steel blank that is drawn into a cup-shaped component having a radial plate section and an axially extending hub section. The cup-shaped component is then formed on a mandrel via a Grob spline machining process to create a spline form in the hub section. The spline form, which originates from the flat flange section to the outer diameter, takes the form of a radius having a large radius on the large outer diameter and a smaller radius on the small outer diameter. Typically, annular clutch components require additional metal cutting or machining after spline formation to form a mounting section on the plate section that is configured to allow for subsequent welding or joining to another torque-transmitting component. To ensure the flatness of the plate section of the annular clutch component, a metal cutting machining process is typically also required. However, machining the plate section requires the cutting tool to cut along the entire length of the plate section, with the edges of the spline form intersecting on both the large outer diameter surface and the small outer diameter surface. This "cutting" edge profile results in an interrupted cut, which in turn causes the machined edge material to be pushed down into the spline form as a burr. This necessitates a subsequent deburring operation to eliminate the burr in the spline form area. Burrs that are not removed prior to clutch assembly can adversely affect the function and service life of the clutch assembly.

[0008] One method of forming external splines is through broaching. During broaching, material is removed from the outer surface of a component to define the external splined surface. However, this process results in a poor surface finish on the minor diameter of the external splines and on the side surfaces of the external splines. The resulting poor surface finish can inhibit smooth sliding motion of the friction plate in contact with the spline surface. Furthermore, the broaching process can have a high cycle time, such as 20 to 30 seconds, and high manufacturing costs.

[0009] Another method for forming external splines is a one-shot injection molding process. In this process, the spline material is formed and can provide an improved surface finish compared to broaching. However, the surface finish is still not as smooth as typically desired. This type of molding can have a cycle time of approximately 15 to 20 seconds and involves high manufacturing costs.

[0010] Another method for forming splines uses a cam die or roller die. Cycle times for this process can be as low as 4 seconds, and the cost is relatively low compared to broaching or one-shot processes. Similar to one-shot processes, this process is a material forming process, rather than a material removal process like broaching. However, in this method, the component's inner diameter is discontinuous. Instead, the component's sidewalls have a roughly constant thickness, with process-defined major and minor outer diameters and major and minor inner diameters.

[0011] Therefore, there is a need to develop a metal forming process that is superior to conventional cold forming (Grob spline forming) processes and is capable of forming annular clutch components. Summary of the Invention

[0012] This section provides a general summary of the disclosure and is not intended to be construed as a comprehensive enumeration of all aspects, features, advantages, and objects of the disclosure.

[0013] One aspect of the present disclosure is to provide a method of manufacturing a high-strength torque transmitting component.

[0014] Another aspect of the present disclosure is to provide a method of manufacturing a high strength torque transmitting component having a high quality surface finish.

[0015] Another aspect of the present disclosure is to provide a method of manufacturing a high strength torque transmitting component having a continuous inner diameter.

[0016] Another aspect of the present disclosure is to provide a method of manufacturing a high strength torque transmitting component using a short cycle time and at a low manufacturing cost.

[0017] According to these and other aspects of the present disclosure, there is provided a splined annular component comprising: a radial flange segment; an axially extending hub segment integrally formed with the radial flange segment; a plurality of splines formed on a radial outer surface of the hub segment, wherein the splines include a large outer diameter and a small outer diameter; and a continuous inner diameter formed on a radial inner surface of the hub segment; wherein the small outer diameter is smooth and formed to require no machining; and wherein the inner diameter is smooth and formed to require no machining.

[0018] In one aspect, the hub portion has a radial thickness that varies around the circumference of the hub portion, wherein a first radial thickness measured between the inner diameter and the minor diameter is less than a second radial thickness measured between the inner diameter and the outer diameter.

[0019] In one aspect, the component includes a chamfered portion disposed at an intersection of the flange segment and the hub segment, wherein the chamfered portion is formed without requiring machining.

[0020] In one aspect, the chamfered portion has an outwardly facing concave profile and an inwardly facing convex profile.

[0021] In one aspect, the minor diameter and the major diameter comprise a mirror finish.

[0022] In one aspect, the component is formed from a blank to which a sodium stearate soap coating is applied.

[0023] In one aspect, the part is formed in a transfer press.

[0024] In one aspect, the flange segment, hub segment and splines are stamped and formed from a common blank.

[0025] In one aspect, the inner diameter includes vertically extending reference marks circumferentially aligned with the minor diameter.

[0026] According to another aspect of the present disclosure, a method for manufacturing a torque transmission component is provided, the method comprising the following steps: providing a flat blank with a flat profile to a transfer press having a first station, a second station, a third station and a fourth station, the first station, the second station, the third station and the fourth station respectively comprising a first die and a first punch, a second die and a second punch, a third die and a third punch, and a fourth die and a fourth punch; at the first station of the transfer press, pressing the blank between the first die and the first punch and forming an unfinished component having a radial flange section and an axial hub section, the unfinished component being in the form of a first cup-shaped preform; transferring the first preform to the second station and between the second die and the second punch The first preform is pressed between the heads and defines a second preform of an unfinished part having a chamfered portion arranged between the flange section and the hub section; the second preform is transferred to the third station and pressed between the third die and the third punch and defines a rough spline preform of the unfinished part having a plurality of rough splines extending radially outward from the hub section; and the rough spline preform is transferred to the fourth station and pressed between the fourth die and the fourth punch and defines a smooth spline part having a final radial flange section and a final axial hub section; wherein the smooth spline part includes a constant inner diameter, a smooth small outer diameter and a smooth large outer diameter along the final axial hub section.

[0027] In one aspect, the first punch, the second punch, the third punch, and the fourth punch have decreasing outer diameters.

[0028] In one aspect, the pressure applied at the first station, the second station, the third station, and the fourth station is different.

[0029] In one aspect, the third and fourth dies include vertically extending protrusions sized and arranged to form the splines.

[0030] In one aspect, at the third station, the hub segment is axially extended in response to the pressing.

[0031] In one aspect, the first die and the first punch define a void at a transition location from the flange segment to the hub segment.

[0032] In one aspect, the second die includes a support portion at a transition location to form the chamfered portion.

[0033] In one aspect, the third station includes a back-pressure sleeve surrounding the third punch, the method further comprising retaining the back-pressure sleeve over the hub segment.

[0034] In one aspect, the method includes pushing material of the rough spline into a space defined by a fourth die.

[0035] In one aspect, no machining operations are performed on the minor diameter of the splines.

[0036] In one aspect, the method includes trimming an upper end portion of a smooth splined component.

[0037] Further areas of applicability will become apparent from the description provided herein.The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.

[0039] Figure 1 Isometric view of a conventional clutch hub of the type used in multi-plate clutch assemblies and manufactured from a cup-shaped preform drawn using the Grob spline forming process and shown in a "pre-machined" state;

[0040] Figure 2 The Grob spline form is shown in the pre-machined state. Figure 1 A partial cross-sectional view of the clutch hub is shown;

[0041] Figure 3 is with Figure 2 A similar partial cross-sectional view showing a subsequent metal cutting machining operation leading to the disadvantages mentioned in the Background section;

[0042] Figure 4 is a top view of a splined component using a new forming process embodying the teachings of the present disclosure and illustrating a continuous inner diameter;

[0043] Figure 5 The diagram shows an external splined surface with a smooth mirror finish. Figure 4 A partial perspective view of a component;

[0044] Figure 6 is a schematic diagram illustrating a transfer press of parts being formed at four stations;

[0045] Figure 7A and Figure 7B is a schematic diagram of a blank used to form a component;

[0046] Figure 8 is a schematic diagram of a blank arranged at a first station of a transfer press before a first draw;

[0047] Figure 9 is a schematic diagram of a blank being formed into a cup-shaped preform during a first draw at a first station;

[0048] Figure 10 is a schematic diagram of a cup-shaped preform arranged at a second station of a transfer press prior to a second draw;

[0049] Figure 11 is a schematic diagram of a preform being formed into a second preform during a second draw at a second station;

[0050] Figure 12A is a schematic diagram of a component disposed at the third station;

[0051] Figure 12B is a schematic diagram of a second preform formed into a rough spline preform during a third draw at a third station;

[0052] Figure 12C is a partial top view of the rough spline preform;

[0053] Figure 13A is a schematic diagram of a rough spline preform at the fourth station;

[0054] Figure 13B is a schematic diagram of a rough spline preform being formed into a final smooth spline component during the fourth draw at the fourth station;

[0055] Figure 13C is a partial top view of the final smooth spline component; and

[0056] Figure 14A and Figure 14B is a schematic diagram of a clutch assembly equipped with one or more annular components made according to the teachings of the present disclosure.

[0057] Corresponding reference numerals indicate corresponding parts and / or subassemblies throughout the several views of the drawings. DETAILED DESCRIPTION

[0058] Example embodiments will now be described more fully with reference to the accompanying drawings.

[0059] Example embodiments are provided so that this disclosure will be exhaustive and will fully convey the scope to those skilled in the art. Many specific details, such as examples of specific components, devices, and methods, are set forth to provide a thorough understanding of the embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, and that the example embodiments may be implemented in many different forms and should not be construed as limiting the scope of the present disclosure. In some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail.

[0060] The terms used herein are only for the purpose of describing specific example embodiments and are not intended to be limiting. Unless the context clearly indicates otherwise, as used herein, the singular forms "a", "an" and "the" may also be intended to include plural forms. The terms "comprise", "including", "contain" and "have" are inclusive and therefore specify the presence of the features, integers, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or groups thereof. Unless specifically identified as an execution order, the method steps, processes and operations described herein should not be interpreted as necessarily requiring them to be performed in the specific order discussed or illustrated. It should also be understood that additional or alternative steps may be adopted.

[0061] When an element or layer is referred to as being “on”, “engaged to”, “connected to” or “coupled to” another element or layer, the element or layer may be directly “on”, engaged, connected or coupled to the other element or layer, or there may be intervening elements or layers. Conversely, when an element is referred to as being “directly on”, “directly engaged to”, “directly connected to” or “directly coupled to” another element or layer, there may be no intervening elements or layers. Other words used to describe the relationship between elements should be interpreted in a similar manner (e.g., “between” versus “directly between”, “adjacent” versus “directly adjacent”, etc.). As used herein, the term “and / or” includes any and all combinations of one or more associated listed items.

[0062] Although the terms first, second, third etc. can be used herein to describe various elements, components, regions, layers and / or parts, these elements, components, regions, layers and / or parts should not be limited by these items. These terms can only be used to distinguish an element, component, region, layer or part from another region, layer or part. Unless clearly indicated by the context, terms such as "first", "second" and other numerical terms do not imply order or sequence when used in this article. Therefore, the first element, component, region, layer or part discussed hereinafter can be referred to as the second element, component, region, layer or part, without departing from the teachings of example embodiments.

[0063] As illustrated in the accompanying drawings, spatially relative terms such as "inside," "outside," "under," "below," "down," "above," "up," etc. may be used herein to describe the relationship of one element or feature to another element or feature. In addition to the orientations depicted in the figures, spatially relative terms may be intended to encompass different orientations of the device in use or operation. For example, if the device in the accompanying drawings is flipped, an element described as "under" or "below" other elements or features will be oriented as "above" the other elements or features. Thus, the exemplary term "below" may encompass both the orientations of above and below. The device may be oriented otherwise (rotated 90 degrees or in other orientations) and the spatially relative descriptors used herein are interpreted accordingly.

[0064] In general, the teachings of this disclosure relate to a method for manufacturing an annular component from a steel billet that provides non-machined, straight-formed splines. The disclosure also relates to an annular clutch component manufactured using this novel component forming process. In one embodiment, the annular component is a clutch hub for a multi-plate friction clutch assembly used in vehicle driveline applications, which may include, but are not limited to, automatic transmissions, transfer cases, power take-off units, torque couplings, and disconnect couplings.

[0065] Figure 1 Until Figure 3 A conventional (prior art) clutch component, hereinafter referred to as an annular clutch component 10, is illustrated having a radial plate or flange section 12 and an axial hub section 14, which together define a cup-shaped member formed by a cold forming operation. The cup-shaped member is then subjected to a spline forming process commonly referred to as Grob spline machining to form a set of circumferentially aligned spline forms 16, or "splines," in the axial hub section 14. Subsequently, trimming and grooving operations are performed to punch out a plurality of oil delivery holes 18 and appropriately size the openings 20 formed in the radial flange section 12. The annular clutch component 10 after these initial operations is then Figure 2A known shortcoming of the Grob spline machining process is the outer radius profile at the junction 22 of the radial flange section 12 and the axial hub section 14. Figure 3 As shown, this profile requires subsequent machining (i.e., a metal cutting operation) to remove material and provide a machined straight spline 24 and a machined step 26 for subsequent laser welding of additional drive / driven components. It is known that the machining operation for the straight spline 24 produces burrs that must be removed via a deburring operation. The above description is a brief disclosure of a well-known method for manufacturing a metal formed clutch hub having splines 16 sized and configured to engage with internal clutch teeth formed on the clutch plates of a multi-plate clutch pack. This "prior art" clutch hub is satisfactory for its intended purpose. However, the following detailed disclosure of an alternative manufacturing method is intended to eliminate the spline machining and step machining operations, as well as to improve the surface finish of the splines.

[0066] to this end, Figure 4 and Figure 5 An improved annular component 100 manufactured according to the novel method disclosed herein is illustrated. In particular, Figure 4 An annular component 100 is shown comprising a cup-shaped member disposed about a central axis and having a radial flange section 102 and an axially extending hub section 104. The radial flange section 102 and the hub section meet at a junction 105. The hub section 104 extends from the junction 105 to an open end opposite the flange section 102.

[0067] As further described below, the cup-shaped preform (formed in the drawing operation) is then subjected to additional pressing and forming operations to form a continuous series of circumferentially aligned spline forms 106 on the hub segment 104. As can be seen, a central opening 110 is also provided, and an oil delivery port (not shown, but similar to the one shown in FIG. 1 ) may be provided through the hub segment 104. Figures 1 to 3 According to the present disclosure, the multi-station transfer press 120 ( Figure 6 ) is used to output a finished component including a non-cutting straight spline form 106 (formed via a transfer press).

[0068] Reference Figure 6 , a transfer press 120 is illustrated including four stations 120a, 120b, 120c, 120d of the transfer press. Each of the stations can be used to define the final formed shape of the component 100 including the splines 106 before any additional finishing operations. Each of the stations will be described in further detail below.

[0069] The first station 120a can be referred to as a cup forming station. The second station 120b can be referred to as a diagonal face forming station. The third station 120c can be referred to as a rough spline forming station. The fourth station 120d can be referred to as a finishing spline forming station. Typically, parts formed after one station are placed into the next station for further forming and then removed and transferred to the next station for additional forming.

[0070] First refer to Figure 6 The transfer press 120 is configured to receive a flat blank 121 at a first station 120a, where a first pressing operation is performed on the blank 121 to initially define a cup-shaped first preform 124 (generally having a radial plate and an axial hub portion). The first preform 124 is transferred to a second station 120b, where the preform 124 undergoes a second pressing operation to define a second preform 126 (further defining the plate-hub interface). The second preform 126 is then transferred to a third station 120c, where the second preform 126 undergoes a third pressing operation to define a first splined preform 128 (forming rough splines on the hub). The first splined preform 128 is then transferred to a fourth station 120 d where it (having a rough spline form) undergoes a fourth pressing operation to further define and shape the splines 106 and define the component 100 .

[0071] For the purpose of further discussion, the various intermediate shapes produced between the initial flat blank 121 and the final formed and splined component 100 (e.g., the various formed and splined preforms 124, 126, 128 described above) may be collectively referred to as an unfinished component 122 as the various intermediate shapes are transferred at the various stations 120a to 120d and pressed and formed. The flat blank 121 may also be generally referred to as an unfinished component 122, and the unfinished component 122 at the final stage of the transfer press 120 may still be referred to as an unfinished component 122 (even though the flat blank 121 has undergone the final step of the transfer press 120 and will be removed from the transfer press as a finished component 100). It will be understood that as the flat blank 121 is formed within the stations and transferred between the stations, once the pressing and forming changes the shape of the flat blank 121 into one of the intermediate shapes 129 of the unfinished component, the shape of the unfinished component 122 will be different from the flat blank 121 that was initially provided.

[0072] Each of the stations of the transfer press 120 can be activated simultaneously so that the first, second, third, and fourth pressing operations are performed approximately simultaneously on different forms of the unfinished component 122 at different stages of the forming process. The cycle time for each pressing operation can thus be reduced to, for example, 4 seconds. The unfinished component 122 can be automatically transferred between stations between pressing instances at different stages of its forming process by an automatic or robotic transfer mechanism (not shown).

[0073] Now refer to Figure 7A and Figure 7B , a flat blank 121 is shown in its flat form. Blank 121 can have a generally flat profile with a constant thickness. In one aspect, blank 121 can be made of high-strength steel. However, it will be appreciated that other materials, such as aluminum, can also be used, depending on the material requirements of the specific type of component 100 being formed. Blank 121 can include a central opening 110, giving blank 122 an annular shape. Depending on the final shape and size of the specific component 100, blanks 121 of various sizes can be used. For the purposes of the discussion herein, specific sizes may be depicted and / or illustrated in the figures for the purposes of illustration and discussion. It will be appreciated that other sizes may also be used. In one aspect, blank 121 can have a diameter of approximately 230 mm, with opening 110 having a diameter of approximately 90 mm. In this example, blank 121 can have a thickness of approximately 3.6 mm. Therefore, in this example, blank 121 can be described as a thin circular disk with a hole located in the center of blank 121.

[0074] In one aspect, the blank 121 can include a coating 121a on both sides of the disc. The coating can be applied via a salt bath and can be used to help reduce heat during the molding operation described herein. In one aspect, the active ingredient in the coating 121a can be sodium stearate soap.

[0075] The thickness of the blank 121 can be selected based on a variety of factors, including the amount of material movement desired, particularly during the formation of the splines 106 on the outer diameter of the component 100. During the spline forming process, material will be pushed, formed, and moved from thick areas into the spline areas with greater volume. In other words, material can be pushed or pulled into the open space defined by the tooling to form the splines 106. Therefore, during the spline forming process, material from the unfinished component 122 is generally not removed from the unfinished component 122, but rather redistributed to define the major and minor diameters of the outer surface, thereby forming the rough spline form and subsequently the finished spline form.

[0076] As described above, the flat blank 121 is introduced into the transfer press 120 and transferred between stations 120a to 120d after undergoing processing into various shaped unfinished parts 122. Each transfer station 120a to 120d will now be described in further detail.

[0077] Reference Figure 8 , a flat blank 121 is shown as being positioned within a first station 120a prior to performing a first pressing operation, also referred to as a first drawing. The first station 120a includes a first die 130 and a first punch 132. In fact, unless otherwise specified, each of the stations includes a die and a punch that can be actuated in a conventional transfer press operation. The punch is disposed above the die. Therefore, relative orientations such as above and below will be used herein to describe the various positioning of the various components. However, it will be understood that different orientations may also be used. For example, the punch may be placed below the die. On the other hand, the punch and die may be arranged to travel horizontally or at an oblique angle relative to the horizontal / vertical direction.

[0078] Figure 8 -xx illustrates a cross-sectional view of the dies and punches of each station 120a to 120d, wherein a first die 130 can support a blank 122, which can be placed above the die 130. In one aspect, the first die 130 can define an outer portion 130a having an inner diameter, the inner diameter of the outer portion 130a defining a die cavity 130c radially defined within the outer portion 130a. In one aspect, the first die 130 can also include a lower portion (not shown) disposed below the cavity 130c, which can combine with the outer portion 130a to define a cup-shaped profile. However, in one aspect, during the initial pressing / forming operation, the lowermost surface of the flat blank 121 can not contact such a lower portion, and thus the lower portion can be excluded. Subsequent forming operations performed at subsequent stations can be used to define the radially extending plate portion of the component.

[0079] The cross-section of the first mold 130 (and other molds described herein) is shown as approximately half of a rotationally symmetrical shape. It will be understood that a similar arrangement is provided on the opposite side of the central axis. Figure 8 As illustrated in FIG, the central hole / opening of the flat blank 121 is shown below the punch 132 on the left side of the figure.

[0080] In one aspect, a retaining ring 134 having an annular shape can be placed over the flat blank 121 when the blank 121 is supported on the mold 130. More specifically, the retaining ring 134 can clamp the blank 121 against the outer portion 130a of the mold 130, and the blank 121 can extend across the mold cavity 130c.

[0081] like Figure 9 , with the blank 122 supported on the die 130 and the retaining ring 134 disposed on the blank 121, the blank 121 can undergo a first drawing, thereby converting the flat blank 121 into an unfinished component 122. The unfinished component 122 will undergo a number of subsequent operations to further refine the shape of the unfinished component 122, particularly by forming the splines 106, until the unfinished component 122 is in a finished form. It will be understood that the unfinished component 122 is the same component as previously described as the flat blank 121, but has a different shape.

[0082] Figure 9 The unfinished part 122 is shown formed into a cup-shaped first preform 124 during the first draw. The first punch 132 moves toward the first die 130. Figure 9 As the first punch 132 moves downward relative to the first die 130, the flat blank 121 is forced downward into the die cavity 130c to produce a first preform 124 of the unfinished component 122. The outer portion 130a of the die 130 may include a rounded inner edge 130d. As the flat blank 121 is pressed downward into the cavity 130c, the flat blank 121 will slide inward along the top of the outer portion 130a and will slide along the rounded edge 130d and fall into the cavity 130c, thereby forming the first preform of the unfinished component 122. In this position, the unfinished component 122 has an outer edge 122a that is disposed below the top of the outer portion 130a of the die 130. In one aspect, the retaining ring 134 can be raised during the first draw to allow the material to slide inward more easily. In another aspect, the retaining ring 134 can be removed or eliminated.

[0083] The first punch 132 is sized to be received within the die cavity 130c and may include a bottom face 132a and an outer diameter 132b. A chamfer 132c may be defined at the intersection of the bottom face 132a and the outer diameter 132b. The chamfer 132c may be rounded at its intersection with the outer diameter 132b and may also be rounded at the intersection between the chamfer 132c and the bottom face 132a.

[0084] When the punch 132 is pressed into the die 130, the blank 122 will be drawn in and bent around the general shape of the punch 132. The chamfer 132c allows the component 122 to be formed to include a rounded edge 122b. The rounded edge 122b of the component 122 does not exactly match the shape of the chamfer 132c, and an open space or gap may be provided between the punch 132 and the blank 122 in the area of the chamfer 132c.

[0085] In one aspect, chamfer 132c can have a concave cross-sectional profile rather than a constant slope. In either case, when the material of unfinished component 122 bends around chamfer 132c, a space can be defined between the curved shape of rounded edge 122b and the surface of chamfer 132c.

[0086] In addition, the die 130 can define a gap or space between the blank 122 and the die 130 in the area of the chamfer 132c. The rounded edge 122b of the unfinished part 122 can be further shaped and processed during a subsequent pressing process, such as at station 120b. Because both the chamfer 132c and the die 130 define a gap relative to the unfinished part 122, the actual shape and curvature of the unfinished part 122 can vary for each part during this step, defining a more predictable curvature and shape in subsequent steps performed on the unfinished part 122.

[0087] It will be appreciated that the punch 132 may also have different shapes (in addition to or in lieu of the chamfer 132c) to define various shape features along the bottom face 132a and the outer diameter 132b.

[0088] exist Figure 9 During the first draw, shown, the punch 132 can be actuated with a force of approximately 30 tons. The first draw requires a relatively low amount of pressure because the flat blank 121 has not yet been formed into its final shape. Instead, the blank 121 is formed into a cup-shaped first preform 124 of its unfinished portion 122. In one aspect, the die 130 can include a gas assist device that applies an upward force toward the punch 132 to provide a reaction force on the punch 132. The gas assist device can also be used at other stations of the transfer press 120.

[0089] like Figure 9 As shown, as the part 122 is formed into the preform 124 , the punch 132 and die 130 may be separated, and the part 122 may be removed and transferred to the second station 120 b .

[0090] Now refer to Figure 10 and Figure 11 , part 122 is shown being formed in second station 120b during a second pressing operation or second drawing. The second station includes a second die 140 and a second punch 142. The shapes of second die 140 and second punch 142 can be generally similar to first die 130 and first punch 132. However, the following differences provide further shaping of blank 122.

[0091] The second die 140 may include a support portion 140e disposed at an inner corner between the outer portion 140a and the lower portion 140b. The support portion 140e contrasts with the aforementioned gap. The support portion 140e is shaped to define the rounded edge 122b of the component 122 in a different shape corresponding to the shape of the support portion 140e. The punch 142 includes a corner shape corresponding to the shape of the support portion 140e.

[0092] like Figure 10 As shown, the support portion 140e can have a generally convex shape, and the punch 142 can include a generally concave shape. Figure 10 As shown, the punch 142 has not yet been fully pressed into engagement with the die 140 , and the component 122 still has the generally curved edges of the first preform 124 .

[0093] Figure 11 The corners of the component 122 are shown to be formed in a shape corresponding to the shapes of the support portion 140e and the punch 142. Figure 11 In the embodiment of the present invention, the punch 142 is pressed downwardly into engagement with the die 140. The shape of the blank 122 at this corner may be application specific, depending on the design requirements of the final part, and is generally unrelated to the design requirements of the spline formation. Figure 11 As shown, the gaps on both sides of the corner of the unfinished component 122 are eliminated, and the corner takes on the shape of the punch 142 and the die 140 at the location of the support portion 140e.

[0094] The second die 140 may include an inner diameter defined by an outer portion 140a that is slightly smaller than the inner diameter defined by the outer portion 130a of the first die 130. The second punch 142 may have a slightly smaller diameter than the first punch 132. The reduced diameter of the punch / die relative to the first station 120a serves to allow a rougher shape to be defined in the first station 120a and then further refined and defined in the second station 120b. The smaller diameter of the punch 142 also allows the punch to be more easily accommodated in the first preform 124.

[0095] Before the punch 142 and the die 140 are transformed together Figure 11 Before the part 122 is in its cup-shaped first preform 124, it can be placed over the upper surface of the second die 140. The second punch 142 will fit inside the inner diameter of the cup shape of the unfinished part 122. The second drawing pressing operation (e.g. Figure 11120a) will effectively define the final shape of the component 100 without the splines. However, the inner diameter may ultimately be slightly smaller during the spline forming process. Additionally, the shape of the chamfered area of the component 122 can be further modified by including a different die shape, if desired. During the second draw, a force of 510 tons can be applied by the second punch 142. The force applied at the second station 120b during this draw is significantly higher than that applied at the first station 120a because the geometry of the unfinished component 122 is more precisely defined.

[0096] After the second draw at the second station 120b, the unfinished component 122 with its second preformed shape 126 may be removed from the second station 120b and transferred to the third station 120c.

[0097] Reference 12A to 12C , a third station 120c is illustrated wherein a component 122 is formed to include a rough form of splines 106 on an outer surface of the unfinished component 122. The third station 120c includes a third punch 152 and a third die 150.

[0098] The outer portion 150a of the mold 150 can define a negative shape relative to the desired shape of the spline 106 for the final molded component 100. In other words, the mold 150 can include a plurality of vertically extending protrusions 150f that correspond to the shape of the recess of the desired spline 106. Each of the protrusions 150f can extend radially inward from the outer portion 150a of the mold. The protrusions 150f can include a lead-in feature 150g located at the uppermost end of the protrusion 150f.

[0099] Prior to actuating the punch 152 and / or die 150 , an ejector (not shown) may hold the blank 122 in position over the die 150 prior to the pressing operation.

[0100] During the pressing operation, punch 152 can apply approximately 140 tons of pressure. During the pressing operation, die 150 pushes / pulls the material of blank 122 upward along outer portion 150a of die 150, extending the axial length of component 122 in the area of splines 106. The pull on the material of component 122 further causes the material to press against the outer diameter of punch 152, which in turn acts to define the inner diameter of component 122. In one example, the top of the unfinished component 122 is approximately 63.9 mm above the bottommost surface of the unfinished component. In the previous pressing step, the top of component 122 was approximately 46.9 mm from the bottommost surface of component 122. The inner diameter of punch 152 is slightly smaller than the inner diameter of second punch 142, allowing third punch 152 to fit within the unfinished component 122 and allowing the material to be formed and pressed against the slightly smaller diameter of third punch 152 during the pressing operation.

[0101] Figure 12A and Figure 12B The punch 152 and die 150 are shown in two positions, wherein: Figure 12A The punch 152 and die 150 are shown prior to the pressing operation, and Figure 12B The die 150 is shown moved upwardly relative to the punch 152, thereby forming the rough form of the splines 106. The inner diameter of the component 122 is generally constant, defined by the diameter of the punch 152.

[0102] In one aspect, as Figure 12A and Figure 12B As shown, a back pressure sleeve 153 is disposed above the component 122 and surrounds the punch 152. The back pressure sleeve 153 can be fixed in position relative to the punch 152 and, as the punch 152 moves downward relative to the die 150, the back pressure sleeve will operate to support the unfinished component 122 as the splines are formed by the relative upward movement of the die 150.

[0103] In another aspect, the back-pressure sleeve 153 can be eliminated and the punch 152 can provide the back-pressure.

[0104] 12 , the component 122 includes the rough-formed external splines 106 thereon, and the annular wall of the component 122 has an extended axial length caused by the pulling and forming of the material caused by the vertical projections impacting the component 122. The component 122, formed into the first splined preform 128 having the rough-formed splines 106 thereon, can then be removed from the third station 120c and transferred to the fourth station 120d. Figure 12C A top view of a first splined preform 128 is illustrated, illustrating the splines 106 of constant inner diameter and rough form.

[0105] 13A to 13C A further spline forming press operation is illustrated in which the rough form splines 106 are formed into a final smooth form. It will be understood that reference to the final form refers to the last station 120d of the disclosed transfer press 120 process, but additional processing may still be performed.

[0106] Similar to the previous stations, component 122 is positioned above or at the upper opening of fourth die 160, with fourth punch 162 configured to be inserted into and press blank 122 into fourth die 160. The outer shape of fourth punch 162 mimics the final inner shape of component 100. Similarly, the shape of fourth die 160 mimics the final outer shape of component 100. The mating shapes of fourth die 160 and fourth punch 162 are configured to form the material of unfinished component 122 into the form of final component 100, and the corresponding shapes of fourth die 160 and fourth punch 162 define the component's smooth, continuous inner diameter 101, chamfered edge 103, and external spline profile 106 of component 100. Fourth station 120d may also be referred to as a finishing spline forming station.

[0107] Before the pressing operation, Figure 13A As shown, the rough form splines 106 are aligned with vertically extending protrusions 160f formed on the outer portion 160a of the fourth mold 160, such that the protrusions 160f are aligned with the vertical recesses present on the rough form splines 106 of the preform 128. Similarly, the radially outwardly projecting rough spline form of the component 122 is aligned with the recesses between the vertically extending protrusions 160f.

[0108] The fourth punch 162 can apply approximately 95 tons of pressure. This amount of pressure is lower than the third station 120c because the rough form of the splines 106 has already appeared. The diameter of the punch 162 is slightly smaller than the diameter of the third punch 152 and defines the smooth continuous inner diameter 101 of the component 100.

[0109] like Figure 13B As shown, at the end of the pressing operation at the fourth station 120d, the unfinished component 122 is in the form of a finished component 100 and can be removed. In this form, since the forming operation is complete, leaving the inner diameter 101, the chamfered area 103, and the external spline geometry 106 in their final formed state, the unfinished component 122 can be referred to as a component 100 or a finished component 100. Figure 13C A top view of a finished component 100 including an inner diameter 101 and splines 106 is illustrated.

[0110] However, additional processing can still be performed on component 100. For example, component 100 can be trimmed via a trimming operation performed at the upper end where the material of component 100 has been pushed / pulled during the spline forming step. However, further machining of splines 106 is not necessary. Furthermore, the smooth and continuous inner diameter 101 of component 100 provides a component in which additional machining of the internal profile of component 100 is not required. In other words, there is generally no need to remove or machine away any material in the radial direction of the component to define the spline profile or the inner or outer diameter of the component.

[0111] Thus, the resulting component 100 includes a smooth and continuous inner diameter 101. The external splines 106 further exhibit a smooth and shiny / mirror-like appearance. This appearance is different from the results of a broaching process or a one-shot injection process. In particular, as Figure 5 As shown, the surface finish on the root of the spline 106 and the outer surface of the spline 106 is mirror-like and very smooth, while other processes produce reference marks in the forming direction (along the length of the spline) and present a rougher finish. In the component 100, reference marks may be present inside the cup form of the component 100, in the corners, due to the material contact with the punch of the transfer press 120. Therefore, both the major and minor outer diameters of the component 100 and the spline 106 of the component 100 are smooth and mirror-like. As shown Figure 4 and Figure 5 As shown, the inner diameter 101 includes vertically extending reference marks that are circumferentially aligned with the minor diameter of the splines 106 .

[0112] The improved surface finish of the splines 106 may improve the performance of the mating component, and in particular may improve the sliding contact between the surface of the mating component and the splines 106 of the component 100 .

[0113] The above-described process and resulting component 100 provide various advantages. For example, the process cycle time is shortened. Due to the reduced cycle time and the reduction in machining operations on the splines, manufacturing costs are reduced. Furthermore, as described above, the surface finish is improved compared to, for example, a broaching process.

[0114] Reference Figure 14AA preliminary schematic illustration of a multi-plate friction clutch assembly 200 is shown disposed between a rotating input member 202 and a rotating output member 204. The clutch assembly 200 includes a clutch hub 206 driven by the input member 202, a clutch drum 208 driving the output member 204, a clutch pack 210, and a power-operated clutch actuator 212. In one aspect, the component 100 can be formed as the clutch hub 206. The clutch pack 210 includes inner clutch plates 214 coupled to the clutch hub 206 via splines and outer clutch plates 216 coupled to the clutch drum 208 via splines. The clutch actuator 212 applies an engagement force to the clutch pack 210 to transfer drive torque from the input member 202 to the output member 204. It is contemplated that at least the clutch hub 206 (and possibly the clutch drum 208) are manufactured using the methods of the present disclosure.

[0115] Figure 14B FIG2 is a basic schematic diagram of a friction clutch assembly 200 used as a power-operated braking device, possibly as part of an automatic transmission. As shown, the clutch drum 208 is now a stationary member, while the clutch hub 206 is coupled to a member of a planetary gear set 220. As is known, the release and braking operation of the friction clutch 200 is used to provide a pair of gear ratio outputs to the output member 204 via the planetary gear set 220.

[0116] The purpose of illustrating these potential uses of the components 100 of the present disclosure is to allow those skilled in the art to understand that these components 100 may be suitable for use in a wide variety of motor vehicle and non-motor vehicle torque transfer applications.

[0117] The foregoing description of the embodiments has been provided for the purpose of illustration and description. The foregoing description is not intended to be exhaustive or limit the present disclosure. Even if not specifically shown or described, the individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but are interchangeable where applicable and can be used in selected embodiments. The individual elements or features of a particular embodiment may also be varied in a variety of ways. Such variations should not be considered as departing from the present disclosure, and all such modifications are intended to be included within the scope of the present disclosure.

Claims

1. A method of manufacturing a torque transmission component, the method comprising the steps of: providing a flat blank having a flat profile to a transfer press having a first station, a second station, a third station, and a fourth station, wherein the first station, the second station, the third station, and the fourth station respectively include a first die and a first punch, a second die and a second punch, a third die and a third punch, and a fourth die and a fourth punch; pressing the blank between the first die and the first punch at the first station of the transfer press and forming an unfinished component having a radial flange section and an axial hub section, the hub section extending axially between a top portion and a bottom portion and defining a central opening in an interior portion of the hub section, the unfinished component being in the form of a cup-shaped first preform; transferring the first preform to the second station and pressing the first preform between the second die and the second punch and defining a second preform of the unfinished component having a chamfered portion disposed between the radial flange segment and the bottom of the hub segment; transferring the second preform to the third station and pressing the second preform between the third die and the third punch and defining a rough splined preform of the unfinished component having a plurality of rough splines extending radially outward from the hub segment and extending between the top and bottom of the hub segment such that tops of the rough splines define a top of the central opening; as well as transferring the rough splined preform to the fourth station and pressing the rough splined preform between the fourth die and the fourth punch to define a smooth splined component having a final radial flange section and a final axial hub section; The smooth splined component includes a constant inner diameter, a smooth small outer diameter and a smooth large outer diameter along the final axial hub section.

2. The method according to claim 1, wherein The first punch, the second punch, the third punch, and the fourth punch have decreasing outer diameters.

3. The method according to claim 1, wherein The pressures applied at the first station, the second station, the third station, and the fourth station are different.

4. The method according to claim 1, wherein The third and fourth dies include vertically extending protrusions sized and arranged to form the rough splines and smooth splines.

5. The method according to claim 1, wherein At the third station, the hub segment is axially extended in response to pressing.

6. The method according to claim 1, wherein The first die and the first punch define a void at a transition location from the radial flange segment to the hub segment.

7. The method according to claim 6, wherein: The second mold includes a support portion at the transition position to shape the chamfered portion.

8. The method according to claim 1, wherein The third station includes a back-pressure sleeve surrounding the third punch, and the method further includes retaining the back-pressure sleeve over the hub segment.

9. The method of claim 1, further comprising pushing material of the rough spline into a space defined by the fourth die.

10. The method according to claim 1, wherein No machining operations are performed on the small outer diameter of the smooth spline.

11. The method of claim 10, further comprising trimming the upper end of the smooth splined member.

12. A splined annular component, the annular component being manufactured by the method according to any one of claims 1 to 11, the annular component comprising: said radial flange section; said hub section; the chamfered portion, wherein the chamfered portion is formed so as to require no machining; The radial flange section, the chamfered portion, and the hub section are integrally formed with one another; a plurality of smooth splines formed on the radially outer surface of the hub segment, wherein the smooth spline comprises the major outer diameter, the minor outer diameter and the continuous inner diameter, and the continuous inner diameter is formed on the radial inner surface of the hub segment; wherein the small outer diameter is formed so as not to require machining; Wherein, the inner diameter is smooth and formed to require no machining.

13. The annular member according to claim 12, wherein The hub segment has a radial thickness that varies around a circumference of the hub segment, wherein a first radial thickness measured between the inner diameter and the small outer diameter is less than a second radial thickness measured between the inner diameter and the large outer diameter.

14. The annular member according to claim 12, wherein The chamfered portion has an outwardly facing concave profile and an inwardly facing convex profile.

15. The annular member according to claim 12, wherein The minor outer diameter and the major outer diameter include a mirror finish.

16. The annular member according to claim 12, wherein The annular member is formed from a blank to which a sodium stearate soap coating is applied.

17. The annular member according to claim 12, wherein The annular member is formed in the transfer press.

18. The annular member according to claim 12, wherein The radial flange segment, the hub segment and the smooth splines are pressed and formed from a common blank.

19. The annular member according to claim 12, wherein The inner diameter includes a vertically extending reference mark circumferentially aligned with the small outer diameter.

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