Method of forming a splined component

A method of manufacturing a torque-transmitting component includes providing a flat blank to a transfer press having a plurality of stations and performing a plurality of pressing operations, in which the flat blank is formed into a cup shape, rough splines are formed on 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.

FIELD

The present disclosure relates generally to a new method of manufacturing splined components and splined components manufactured in accordance with this new method. More particularly, the present disclosure relates to components manufactured using draw forming and other pressing operations all of which are capable of being sequentially provided in a transfer press unit.

BACKGROUND

Power transfer devices of the type used in automotive applications, such as for example, automatic transmissions, torque couplings, power take-off units and transfer cases, are commonly equipped with a power-operated multi-plate clutch assembly. Typically, the multi-plate clutch assembly includes a first clutch number (such as a clutch hub) driven by an input component, a second clutch member (such as a clutch drum) driving an output component, a multi-plate clutch pack disposed therebetween, and a powered clutch actuator for engaging the clutch pack and transmitting 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 that are configured to engage and mesh with corresponding clutch teeth formed on the clutch plates of the clutch pack.

To reduce the mass of such clutch members while maintaining the required high-strength and torque transmission characteristics, many modern clutch hubs and drums, hereinafter referred to cumulatively 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 current high volume processes for manufacturing annular clutch components include Grob spline processing and flow form processing.

Due to the design of these formed sheet-metal clutch components, the currently available processes also present several known shortcomings. Specifically, the annular clutch components are initially formed from a steel blank that is drawn into a cup-shaped component having a radial plate segment and an axially-extending hub segment. The cup-shaped component is subsequently formed over a mandrel to produce a spline form in the hub segment via the Grob splining process. The start of the spline form from the flat flange segment to the outer diameter is in the form of a radius with a large radius on the major OD and a smaller radius on the minor OD. Typically, the annular clutch component requires an additional metal-cutting or machining process after forming the splines to form a mounting segment on the plate segment configured to allow subsequent welding or joining of another torque transmitting component. In order to guarantee the flatness of the plate segment of the annular clutch component, a metal-cutting machining process is also typically required. However, machining of the plate segment requires the cutter tool to cut along the entire length of the plate segment and encounter the edge of the spline form on both the major and minor OD surfaces. This “cut” 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. As such, a subsequent deburring operation is required to remove the burrs in the spline form area. Burrs that are not removed prior to assembly of the clutch assembly can have a detrimental impact on the function and service life of the clutch assembly.

One method of forming external splines is a broaching process. In the broaching process, material is removed from the outer surface of the component to define the external splined surface. However, this process may result in a poor surface finish on the minor diameter of the external spline, as well as on the flanks of the external spline. The resulting poor surface finish can prevent smooth sliding motion of a friction plate that is in contact with the spline surfaces. Additionally, the broaching process can have high cycle times, such as 20-30 seconds, as well as a high manufacturing cost.

Another method forming external splines is a one-shot forming process. In a one-shot process, the material of the spline is formed, and can provide an improved surface finish relative to the broaching process. However, the surface finish is still not as smooth as typically desired. The cycle time of such forming can be about 15-20 seconds, and includes a high manufacturing cost.

A further method of forming splines uses a cam die or roller die. The cycle time for such process can be as low as 4 seconds, and can have a relatively low cost relative to the broaching or one shot processes. Similar to the one shot process, this process is a material forming process, rather than a material removal process like broaching. However, in this approach, the internal diameter of the part is not continuous. Rather, the sidewall of the part has a generally constant thickness, with major and minor outer diameters as well as major and minor inner diameters defined by the process.

To this end, a need exists to develop a metal forming process capable of forming an annular clutch component which is an advancement over conventional cold forming (Grob spline forming) processes.

SUMMARY

This section provides a general summary of the present disclosure, and is not intended to be interpreted as a comprehensive listing of all of its aspects, features, advantages and objectives.

It is an aspect of the present disclosure to provide a method of manufacturing a high strength torque-transmitting component.

It is another aspect of the present disclosure to provide a method of manufacturing a high strength torque-transmitting component having a high-quality surface finish.

It is another aspect of the present disclosure to provide a method of manufacturing a high strength torque-transmitting component having a continuous internal diameter.

It is another aspect of the present disclosure to provide a method of manufacturing a high strength torque-transmitting component using a short-cycle time a low manufacturing cost.

According to these and other aspects of the disclosure, a splined annular component is provided, comprising: a radial flange segment; an axially-extending hub segment integrally formed with the radial flange segment; a plurality of splines formed on a radially outer surface of the hub segment, wherein the splines include a major outer diameter and a minor outer diameter; and a continuous inner diameter formed on a radially inner surface of the hub segment; wherein the minor outer diameter is smooth and formed without machining; wherein the inner diameter is smooth and formed without machining.

In one aspect, the hub portion has a radial thickness that varies around a circumference thereof, 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.

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

In one aspect, the chamfer portion has an outwardly facing concave profile and an inwardly facing convex profile.

In one aspect, the minor diameter and the major diameter include a mirror-like finish.

In one aspect, the component is formed from a blank having a sodium stearate soap coating applied thereto.

In one aspect, the component is formed in a transfer press.

In one aspect, the flange segment, hub segment, and splines are pressed and formed from a common blank.

In one aspect, the inner diameter includes vertically extending witness marks circumferentially aligned with the minor diameter.

According to yet another aspect of the disclosure, a method of manufacturing a torque-transmitting component is provided, the method comprising the steps of: providing a flat blank having a flat profile to a transfer press having a first station, second station, third station, and fourth station, the first, second, third, and fourth stations including a first, second, third, and fourth die and a first, second, third, and fourth punch, respectively; 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 segment and an axial hub segment, the unfinished component in the form of a first cup-shaped 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 chamfer portion disposed between the flange segment and 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 transferring the rough splined preform to the fourth station and pressing the rough splined preform between the fourth die and the fourth punch and defining a smooth splined component having a final radial flange segment and a final axial hub segment; wherein the smooth splined component includes, along the final axial hub segment, a constant inner diameter, a smooth minor outer diameter, and a smooth major outer diameter.

In one aspect, the first, second, third and fourth punches have decreasing outer diameters.

In one aspect, the pressure applied at the first, second, third, and fourth stations varies.

In one aspect, the third and fourth dies include vertical extending projections sized and arranged to shape the splines.

In one aspect, at the third station, the hub segment is axially elongated in response to the pressing.

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

In one aspect, the second die includes a support portion at the location of the transition to shape the chamfer portion.

In one aspect, the third station includes a counter-pressure sleeve surrounding the third punch, the method further comprising holding the counter-pressure sleeve above the hub segment.

In one aspect, the method includes pushing material of the rough splines into space defined by the fourth die.

In one aspect, no machining operation is performed on the minor diameter of the splines.

In one aspect, the method includes trimming an upper end of the smooth splined component.

Corresponding reference numerals indicate corresponding parts and/or sub-assemblies throughout the several views of the drawings.

DETAILED DESCRIPTION

In general, the teachings of the present disclosure are directed toward a method of manufacturing an annular component from a blank of steel and which is capable of providing non-machined straight formed splines. The present disclosure further relates to an annular clutch component fabricated using this new part forming process. In one embodiment, the annular component is a clutch hub of a multi-plate friction clutch assembly for use in vehicular drivetrain applications which may include, without limitations, automatic transmissions, transfer cases, power take-off units, torque couplings and disconnect couplings.

FIGS.1through3illustrate a conventional (prior art) clutch component, hereinafter annular clutch component10, having a radial plate or flange segment12and axial hub segment14while together define a cup-shaped member formed by a cold-forming operation. The cup-shaped member is subsequently exposed to a spline forming process, commonly referred to as Grob splining, to form a set of circumferentially-aligned spline forms16, i.e., “splines”, in axial hub segment14. Subsequently, a trim and slotting operation is conducted to pierce a plurality of oil transfer holes18and to properly size an aperture20formed in radial flange segment12. Annular clutch component10is shown inFIG.2following these initial operations. A known shortcoming of the Grob splining process is located at the outer radius profile at an interface22of radial flange segment12and axial hub segment14. This profile requires subsequent machining (i.e. a metal cutting operation) as shown inFIG.3to remove material and provided machined straight splines24and a machined step26for subsequent laser welding of additional drive/driven component. The machining operation for the straight splines24is known to result in burrs that must be removed via a deburring operation. The above-noted description is an abbreviated disclosure of a well-known method for manufacturing metal-formed clutch hubs with splines16sized and configured to mesh with internal clutch teeth formed on clutch plates of the multi-plate clutch pack. Such “prior art” clutch hubs are satisfactory for their intended purposes. 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.

To this end,FIGS.4and5illustrate an improved annular component100manufactured in accordance with a new method that is disclosed herein. In particular,FIG.4shows annular component100to include a cup-shaped member that is disposed about a center axis and has a radial flange segment102and an axially-extending hub segment104. The radial flange segment102and hub segment meet at an interface105. The hub segment104extends from the interface105to an open end that is opposite flange segment102.

As further described below, a cup-shaped pre-form (formed in a drawing operation) is subsequently exposed to additional pressing and forming operations to form a continuous series of circumferentially-aligned spline forms106on hub segment104. As seen, a central aperture110is also provided, and oil transfer holes (not shown, but similar to those shownFIGS.1-3) may be provided through the hub segment104. In accordance with the present disclosures, multi-station transfer press120(FIG.6) is used to output a finished part including non-cut straight spline forms106(formed via transfer press).

Referring toFIG.6, transfer press120is illustrated, including four stations120a,120b,120c,120dthereof. Each of the stations may be used to define the final formed shape of the component100, including the splines106, prior to any additional finishing operations. Each of the stations will be described in further detail below.

First station120amay be referred to as cup-forming station. Second station120bmay be referred to as diagonal face forming station. Third station120cmay be referred to as rough spline forming station. Fourth station120dmay be referred to as finish spline forming station. Generally, the component formed following one station is placed into the next station to undergo further forming, and is then removed and transferred to the next station for additional forming.

With reference initially toFIG.6, transfer press120is configured to a receive a flat blank121at the first station120a, wherein a first pressing operation is performed on the blank121to begin the defining a first cup-shaped pre-form124(having generally radial plate and axial hub portions). The first pre-form124is transferred to the second station120b, where the pre-form124undergoes a second pressing operation to define a second pre-form126(further defining the plate and hub interface). The second pre-form126is then transferred to the third station120c, where the second pre-form126undergoes a third pressing operation to define a first splined pre-form128(a rough spline formed on the hub). The first splined pre-form128is then transferred to the fourth station120d, where the first splined pre-form128(having the rough spline form) undergoes a fourth pressing operation to further define and shape the splines106and define the component100.

For the purposes of further discussion, the various intermediate shapes created between the initial flat blank121and the final shaped and splined component100(for example the various shaped and splined pre-forms124,126,128described above) may be referred to collectively as unfinished component122as they are transferred and pressed and formed at various stations120a-120d. Flat blank121may also be referred to generally as unfinished component122, and the unfinished component122at the final stage of the transfer press120may still be referred to as the unfinished component122(even though it has undergone the final step of the transfer press120and will be removed from the transfer press as finished component100). It will be appreciated that once the pressing and forming changes the shape of the flat blank121to one of the intermediate shapes of the unfinished component122, that the shape of the unfinished component122will be different than the initially provided flat blank121, as it is formed within stations and transferred among stations.

Each of the stations of the transfer press120may be actuated at the same time, such that the first, second, third, and fourth pressing operations are performed generally simultaneously to different forms of the unfinished component122that are in different stages of the forming process. The cycle time per pressing operation may therefore be reduced, such as 4 seconds. The unfinished component122, in its various stages of forming, may be automatically transferred between stations between pressing instances by an automatic or robotic transfer mechanism (not shown).

Referring now toFIGS.7A and7B, the flat blank121is illustrated in its flat form. The blank121may have a generally flat profile with a constant thickness. The blank121may be made from high strength steel, in one aspect. However, it will be appreciated that other materials may also be used, such as aluminum, depending on the material requirements of the particular type of component100being formed. The blank121may include central aperture110, such that the blank121has an annular shape. Various dimensions of the blank121may be used depending on the final shape and size of the particular component100. For purposes of discussion herein, specific dimensions may be described and/or illustrated in the figures for illustrative and discussion purposes. It will be appreciated that other dimensions could also be used. In one aspect, the blank121may have a diameter of about 230 mm, with aperture110having a diameter of about 90 mm. The thickness of the blank121in this example may be about 3.6 mm. The blank121may therefore be described, in this example, as a thin circular shaped disc with a hole located in the center of the blank121.

In one aspect, the blank121may include a coating on both sides of the disc-shape. The coating may be applied via salt bath, and may be used to assist in reducing heat during the forming operation described herein. In one aspect, the active ingredient in the coating may be sodium stearate soap.

The thickness of the blank121may be chosen based on a variety of factors, including desired amount of material movement, in particular the movement that occurs during the forming of the splines106on the outer diameter of the component100. During the spline-forming processes, material will be pushed, formed, and will move from a thick area into a spline region with a larger volume. Put another way, material may be pushed or pulled into open-spaces defined by the tooling to form the splines106. Thus, material of the unfinished component122, in the spline forming process, is generally not removed from the unfinished component122, but rather is re-allocated to define the major and minor diameters of the exterior surface to form the rough and subsequently finished spline forms.

The flat blank121is introduced into the transfer press120and transferred between stations120a-d, as described above, after undergoing processing into the various shapes of the unfinished component122. Each transfer station120a-dwill now be described in further detail.

Referring toFIG.8, the flat blank121is shown positioned within the first station120a, prior to performing the first pressing operation, also referred to as the first draw. The first station120aincludes a first die130and a first punch132. Indeed, each of the stations includes a die and a punch, which may be actuated in a traditional transfer press operation, unless otherwise noted. The punches are disposed above the dies. Accordingly, relative orientations, such as above and below will be used herein to described various positioning of the various components. However, it will be appreciated that different orientations could also be used. For example, a punch could be placed below a die. In another aspect, the punch and die could be arranged to travel horizontally or at an oblique angle relative to horizontal/vertical.

FIGS.8-12B and13A-13Billustrate cross-sectional views of the dies and punches of the various stations120a-d, The first die130may support the blank121, which may be placed above the die130. In one aspect, the first die130may define an outer portion130ahaving an inner diameter defining a die cavity130cdefined radially within the outer portion130a. In one aspect, the first die130may also include a lower portion (not shown) disposed below the cavity130c, which may combine with outer portion130ato define a cup-shaped profile. However, in one aspect, during an initial pressing/forming operation, a lowermost surface of the flat blank121may not make contact with such a lower portion, and therefore the lower portion may be excluded. Subsequent forming operations at subsequent stations may be used to define the radially extending plate portion of the component.

The first die130(and the other dies described herein) are illustrated cross-sectionally as generally one half of a rotationally symmetrical shape. It will be appreciated that a similar arrangement is disposed on the opposite side of a central axis. As illustrated inFIG.8, the central hole/opening of the flat blank121is shown on the left side of the figure under the punch132.

In one aspect, a retention ring134, having an annular shape, may be placed above the flat blank121when the blank121is supported on the die130. More particularly, the retention ring134may sandwich the blank121against the outer portion130aof the die130, and the blank121may extend over the die cavity130c.

With the blank121supported on the die130and the retention ring134disposed on the blank121, the blank121may undergo the first draw, as illustrated inFIG.9, thereby transitioning the flat blank121to the unfinished component122. The unfinished component122will undergo multiple subsequent operations to further refine its shape until it is in finished form, in particular by forming the splines106. It will be appreciated that the unfinished component122is the same piece that was previously described as the flat blank121, but having a different shape.

FIG.9shows the unfinished component122formed into a cup-shaped first pre-form124during the first draw. The first punch132moves toward the first die130into the position shown inFIG.9. As the first punch132moves downward relative to the first die130, the flat blank121is forced downward into the die cavity130cto create the first pre-form124of the unfinished component122. The outer portion130aof the die130may include a radiused inner edge130d. As the flat blank121is pressed downward into the cavity130c, the flat blank121will slide inward along the top of the outer portion130a, and will slide along the radiused edged130dand drop into the cavity130c, forming the first pre-form of the unfinished component122. The unfinished component122in this position has an outer edge122athat is disposed below the top of the outer portion130aof the die130. In one aspect, the retainer ring134may be lifted during the first draw to allow the material to more easily slide inward. In another aspect, the retainer ring134may be removed or excluded.

The first punch132is sized to be received within the die cavity130c, and may include a bottom face132aand an outer diameter. A chamfer132cmay be defined at the intersection of the bottom face132aand the outer diameter. The chamfer132cmay be radiused at its intersection with the outer diameter and may also be radiused at the intersection between the chamfer132cand the bottom face132a.

When the punch132is pressed into the die130, the blank121will be drawn in and bend around the general shape of the punch132. The chamfer132cpermits the component122to be formed to include a radiused edge122b. The radiused edge122bof the component122does not exactly match the shape of the chamfer132c, and open space or void may be disposed between the punch132and the component122at the area of the chamfer132c.

In one aspect, the chamfer132cmay have a concave cross-sectional profile, rather than a constant slope. In either case, as the material of the unfinished component122bends around the chamfer132c, space may be defined between the curved shape of radiused edge122band the surface of the chamfer132c.

Additionally, the die130may define a void or space between the component122and the die130at the area of the chamfer132c. The radiused edge122bof the unfinished component122can be further shaped and processed in subsequent pressing processes, such as at station120b. Because the chamfer132cand die130both define voids relative to the unfinished component122, the actual shape and curvature of the unfinished component122may vary during this step for each part, with more predictable curvatures and shapes being defined in subsequent steps performed on the unfinished component122.

It will be appreciated that the punch132may also have different shapes (in addition to or alternative from the chamfer132c) to define various shapes features along the bottom face132aand outer diameter.

During the first draw shown inFIG.9, the punch132may be actuated with about 30 tons of force. The first draw requires a relative low amount of pressure because the flat blank121is not being formed to its final shape. Rather, the blank121is being formed into its cup shaped first pre-form124of the unfinished component122. In one aspect, the die130may include a gas assist that applies an upward force toward the punch132to provide a reaction force on the punch132. Gas assist may be used at other stations of the transfer press120, as well.

With the component122shaped into pre-form124as shown inFIG.9, the punch132and die130may separate, and the component122may be removed and transferred to the second station120b.

Referring now toFIGS.10and11, the component122is shown being shaped in the second station120bduring a second pressing operation, or second draw. The second station includes a second die140and a second punch142. The shape of the second die140and the second punch142may be generally similar to the first die130and first punch132. However, the following differences provide further shaping of the component122.

The second die140may include a support portion140cdisposed at the inner corner between an outer portion140aand a lower portion140b. The support portion140cis in contrast to the void described above. The support portion140cis shaped to define the radiused edge122bof component122into a different shape corresponding to the shape of the support portion140c. The punch142includes a corner shape corresponding to the shape of the support portion140c.

As shown inFIG.10, the support portion140cmay have a generally convex shape, and the punch142may include a generally concave shape. As shown inFIG.10, the punch142is not yet fully pressed into engagement with the die140, and the component122still has a generally curved edge of the first pre-form124.

FIG.11illustrates the corner of the component122being formed in a shape corresponding to the shape of the support portion140cand the punch142. InFIG.11, the punch142is pressed down into engagement with the die140. The shape at this corner of the component122may be application specific depending on the design needs of the final component, and is generally unrelated to the design needs of the spline formation. As shown inFIG.11, the voids on either side of the corner of the unfinished component122are eliminated and the corner takes the shape of the punch142and die140at the location of the support portion140c.

The second die140may include an inner diameter defined by the outer portion140athat is slightly smaller than the inner diameter defined by the outer portion130aof the first die130. The second punch142may have a slightly smaller diameter than the first punch132. The reduction in diameter from the punch/die relative to the first station120afunctions to allow for rougher shape to be defined in the first station120aand then further refined and defined in the second station120b. The smaller diameter of the punch142also allows for the punch to be more easily received in the first pre-form124.

Prior to translating the punch142and the die140together to the position shown inFIG.11, the component122, in its cup shaped first pre-form124, may be placed above the upper surface of the second die140. The second punch142will fit inside the inner diameter of the cup shape of the unfinished component122. The pressing operation of the second draw (shown inFIG.11) will effectively define the final shape of the component100, absent the splines. However, the inner diameter may ultimately become slightly smaller during the spline formation processes. Additionally, the chamfer area of the component122may be further modified in its shape, if desired, by including different die shapes. During the second draw, 510 tons of force may be applied by the second punch142. The force applied at the second station120bduring this draw is substantially higher than at the first station120a, because the geometry of unfinished component122is being more precisely defined.

Following the second draw at the second station120b, the unfinished component122with its second pre-formed shape126may be removed from the second station120band transferred to the third station120c.

Referring toFIGS.12A-12C, the third station120cis illustrated, with the component122being formed to include a rough form of the splines106on an outer surface of the unfinished component122. The third station120cincludes a third punch152and a third die150.

An outer portion150aof the die150may define a negative shape relative to the desired shape of the splines106for the final formed component100. Put another way, the die150may include a plurality of vertical extending projections150fthat correspond to the shape of the indentations of the desired splines106. Each of the projections150fmay extend radially inward from the outer portion150aof the die. The projections150fmay include a lead-in feature150gat an uppermost end of the projection150f.

Prior to actuating the punch152and/or die150, an injector (not shown) may hold the component122above the position of the die150prior to the pressing operation.

During the pressing operation, the punch152may apply about 140 tons of pressure. During the pressing operation, the die150will push/pull material of the component122upward along the outer portion150aof the die150, extending the axial length of the component122in the area of the splines106. The pull of material of the component122will further cause the material to press against the outer diameter of the punch152, which will operate to define the inner diameter of the component122. In one example, the top of the unfinished component122is about 63.9 mm above the bottom-most surface of the unfinished component. In the prior pressing step, the top of the component122was about 46.9 mm from the bottom-most surface of the component122. The inner diameter of the punch152is slightly smaller than the inner diameter of the second punch142, thereby allowing the third punch152to fit within the unfinished component122, and allowing material to be formed and pressed against the slightly smaller diameter of the third punch152during the pressing operation.

FIGS.12A and12Billustrates the punch152and die150in two positions, withFIG.12Ashowing the punch152and die150prior to a pressing operation, andFIG.12Bshowing the die150moved upward relative to the punch152, thereby forming the rough form of the splines106. The inner diameter122of the component is generally constant, defined by the diameter of the punch152.

In one aspect, shown inFIGS.12A and12B, a counter-pressure sleeve153is disposed above the component122and surrounding the punch152. The counter-pressure sleeve153may be fixed in place relative to the punch152, and when the punch152moves downward relative to the die150, the counter-pressure sleeve will operate to brace the unfinished component122as the splines are formed by the relative upward movement of the die150.

In another aspect, the counter-pressure sleeve153may be excluded, and the punch152may provide the counter-pressure.

Following the pressing operation of the third station120cofFIG.12, the component122includes a rough forming of the external splines106thereon, and the annular wall of the component122has an extended axial length caused by the pull and forming of material caused by the vertical projections impacting the component122. The component122, shaped as the first splined pre-form128, having the rough form of the splines106thereon, can subsequently be removed and transferred from the third station120cto the fourth station120d.FIG.12Cillustrates a top view of the first splined pre-form128illustrating the constant inner diameter and the rough form of the splines106.

FIGS.13A-13Cillustrates a further spline-forming pressing operation, in which the rough form of the splines106are formed into a final smooth form. It will be appreciated that the reference to the final form refers to the last station120dof the disclosed transfer press120process, but that additional processing may still be performed.

Similar to the prior stations, the component122is positioned above or at the upper opening of a fourth die160, with a fourth punch162configured to be inserted into the component122and to press the blank122into the fourth die160. The outer shape of the fourth punch162mimics the final inner shape of the component100. Similarly, the shape of the fourth die160mimics the final outer shape of the component100. The cooperating shapes of the fourth die160and the fourth punch162are arranged to form the material of the unfinished component122into the form of the final component100, and the corresponding shapes of the fourth die160and the fourth punch162will define a smooth continuous inner diameter101of the component, a chamfered edge103, and the outer spline profile106of the component100. The fourth station120dmay also be referred to as the finish spline forming station.

Prior to the pressing operation, as shown inFIG.13A, the rough form of the splines106are aligned with vertical extending projections160fformed on the outer portion of the fourth die160, such that the projections160fare aligned with the vertical recesses present on the rough form of the splines106of pre-form128. Similarly, the radially outwardly projecting rough spline forms of the component122are aligned with the recesses between the vertically extending projections160f.

The fourth punch162may be applied with about 95 tons of pressure. This amount of pressure is lower than the third station120c, because the rough form of the splines106has already occurred. The diameter of the punch162is slightly smaller than the diameter of the third punch152, and defines the smooth continuous inner diameter101of the component100

At the conclusion of the pressing operation of the fourth station120d, shown inFIG.13B, the unfinished component122is in the form of the finished component100and may be removed. In this form, the unfinished component122may be referred to as the component100or finished component100due to the forming operation being complete, such that the inner diameter101, chamfer area103, and external spline geometry106is in its final formed condition.FIG.13Cillustrates a top view of finished component100, including the inner diameter101and the splines106.

However, additional processing on the component100may still be performed. For example, the component100may be trimmed via a trimming operation at the upper end where the material of the component100had been pushed/pulled during the spline forming steps. However, no further machining of the spline106is necessary. Additionally, the smooth and continuous inner diameter101of the component100provides for a component where no additional machining is necessary on the inside profile of the component100. Put another way, generally no material needs to be removed or machined away in the radial direction of the component to define the spline profile or the inner or outer diameters of the component.

Thus, the resulting component100includes the smooth and continuous inner diameter101. The external splines106further exhibit a smooth and shiny/mirror-like appearance. This appearance is different than the result of a broaching or one-shot process. In particular, the surface finish in the root of the spline106and on the outer surface of the spline106is mirror-like and very smooth, as shown inFIG.5, while other processes produce witness marks in the direction of forming (along the length of the spline) and exhibit a rougher finish. In the component100, witness marks may be present inside the cup-form of the component100in the corner as a result of the contact of the material with the punches of the transfer press120. Thus, both the major and minor outer diameters of the component100and the splines106thereof are smooth and mirror-like. As shown inFIGS.4and5, the inner diameter101includes vertically extending witness marks circumferentially aligned with the minor diameter of the splines106.

The improved surface finish of the splines106can improve performance with mating components, in particular sliding contact between the surfaces of the mating component and the splines106of the component100may be improved.

The above-described process and resulting component100provides various advantages. For example, the cycle time of the process is reduced. The manufacturing cost is reduced as a result of the reduced cycle time and reduction of machining operations on the spline. Additionally, the surface finish, as described above, is improved compared to, for example, the broaching process.

Referring toFIG.14A, a rudimentary schematic illustration of a multi-plate friction clutch assembly200is shown disposed between a rotary input component202and a rotary output component204. Clutch assembly200includes a clutch hub206driven by input component202, a clutch drum208driving output component204, a clutch pack210, and a power-operated clutch actuator212. In one aspect, the component100may be formed as the clutch hub206. Clutch pack210includes inner clutch plates214coupled via splines to clutch hub206and outer clutch plates216coupled via splines to clutch drum208. Clutch actuator212applies an engagement force to clutch pack210to transfer drive torque from input component202to output component204. It is contemplated that at least clutch hub206(and possibly clutch drum208) is manufactured using the method of the present disclosure.

FIG.14Bis a rudimentary schematic illustration of friction clutch assembly200being used as a power-operated brake device, possibly as part of an automatic transmission. As shown, clutch drum208is now a stationary member, while clutch hub206is coupled to a component of a planetary gearset220. As is known, released and braked operation of friction clutch200functions to provide a pair of speed ratio outputs to output component204through planetary gearset220.

The purpose of illustrating these potential uses of the components100of the present disclosure is to permit those skilled in the art to appreciate that these components100may be adapted for a plethora of automotive and non-automotive torque transmission applications.