Stamping press forming of outer diameter helical splines

A press assembly for forming outer helical splines on a blank includes an upper press shoe assembly and a die shoe assembly. The upper press shoe assembly includes an upper rotatable portion rotatable relative to an upper stationary portion. The lower portion includes a lower rotatable portion rotatable relative to a lower stationary portion. The unfinished blank is supported by the lower portion, and the upper portion is moveable into engagement with the blank. The upper rotatable portion joins with the lower rotatable portion for conjoint rotation relative to the upper and lower stationary portions via upper and lower helical meshes defined between the rotatable and stationary portions. The helical meshes convert downward force into rotation and translation of the blank into a spline forming die of the lower stationary portion to create the outer helical splines.

FIELD OF THE INVENTION

The present disclosure is generally related to a method of producing a helical outer diameter splined component using a stamping press. The present disclosure is further related to a helical shaped punch and die tooling to form a helical outer diameter in a stamped component. The present disclosure is further related to using press force with helical shaped tooling to coordinate rotation of a punch into a die to form a helical outer diameter in a stamped component without the need for rotating press tooling by external means.

BACKGROUND OF THE INVENTION

Opposed to straight tooth forms, helical gear or spline tooth forms have a non-parallel or inclined arrangement relative to the axis of rotation of the gear. Due to the non-parallel tooth angle, the manufacturing of helical tooth forms has an increased complexity and includes higher manufacturing costs, driven by time to produce and capital equipment required. Current production of helical gear forms is achieved by cutting or grinding the tooth form. One example of cutting is hobbing where a disc requiring helical teeth around the entire outer diameter is rotated in steps. A hob forms teeth on a portion or sector of the overall diameter, so the part is rotated through several of these sectors until complete. This is a lengthy and costly process which also could require further finishing operations to achieve a final gear form. Other processes such as rolling are used for helical splines, but typically on solid shafts due to the compressive forces involved it would be difficult to implement on a disc shaped component.

In view of the above, a need exists to continue development of new and improved manufacturing processes for disc shaped components with an external helical tooth form. A solution needs to create an accurate and final geometry while producing a high volume of parts in a cost-efficient manner. It would also be beneficial to utilize existing stamping manufacturing equipment to reduce capital expense.

SUMMARY

It is an aspect of the present disclosure to provide a process capable of forming a disc with an external helical spline gear form using stamping press equipment.

It is an aspect of the present disclosure to provide a process where the final part geometry does not require additional finishing operations.

It is an aspect to transform the vertical press force into a rotational component during the process to accurately form the helical gear form.

It is a related aspect of the present disclosure to achieve the rotational tooling motion required to develop a helical tooth form without any external rotating driving means.

It is a related aspect of the present disclosure to utilize a press stripper as a drive plate.

It is a related aspect of the present disclosure to utilize forces from gas springs on the drive plate and in conjunction with helical gear form tooling to impart a rotation on the punch while forming the final part in the die.

It is a related aspect of the present disclosure to have a punch and die with a helical spline form with the same dimensional characteristics as the final part.

It is a related aspect of the present disclosure to achieve a final part geometry which includes a quality surface finish due to a smooth sheering across the helical tooth.

In accordance with these and other aspects, a press arrangement has been arranged to produce, in high volume, a disc shaped component with a helical tooth form on its outer diameter. This non limiting helical spline could also be considered a helical gear form on the external diameter of a circular part. The press will comprise an upper portion and a lower portion, each with tooling within these portions which will rotate during the stamping process while traveling vertically to punch the blank into a final form. The upper portion includes the upper die shoe and a stripper which has been configured to operate as a drive plate using a first helical gear interface to impart a rotational moment on the punch from a vertical load applied by gas springs. The lower die shoe retains a stationary die with a second helical interface. Internally to the second helical interface is a support structure which rotates in conjunction with the punch through drive pins or clamping forces through the blank. As press force is applied to the punch, the force is applied to a rotatable tooling and vertically traveling through and shearing the blank as the punch enters into the die. A synchronized indexing or rotation of the punch and lower support structure occurs driven by the helical interfaces which match the helical angle of the final part and a helical form is stamped on the outer diameter of the blank. As the press force is reduced, the rotated components reverse direction with the assistance of a lower gas spring and the final part is removed from the die when the press opens. No other mechanized driver (i.e. motor or mechanical linkage tied to press movement) is used to index or rotate the tooling.

In another aspect, a method for forming external helical spline features on a circular blank is provided, the method including the steps of: providing a lower die shoe assembly configured to receive a gear blank having an unfinished condition, the lower die shoe assembly including a lower stationary portion and a lower rotatable portion rotatable relative to the lower stationary portion; providing an upper punch shoe assembly configured to move relative toward the lower die shoe assembly, the upper punch shoe assembly including an upper stationary portion and an upper rotatable portion rotatable relative to the upper stationary portion; providing the gear blank between the upper punch shoe assembly and lower die shoe assembly and supporting the gear blank on the lower die shoe assembly; bringing the upper punch shoe assembly into contact with the gear blank; driving the upper rotatable portion downward relative to the upper stationary portion and rotating the upper rotatable portion relative to the upper stationary portion; driving the blank downward into to the lower stationary portion and rotating the blank relative to the lower stationary portion; in response thereto, forming an external helical spline on the blank with the lower stationary portion.

In one aspect, an upper helical mesh is defined between the upper stationary portion and the upper rotatable portion and a lower helical mesh is defined between the lower stationary portion and the lower rotatable portion, wherein an angle of the upper and lower helical mesh is the same.

In one aspect, an angle of the external helical spline matches the angle of the upper and lower helical mesh.

In one aspect, the upper rotatable portion includes external toothing, wherein the external toothing is received with internal toothing of the lower stationary portion when the upper rotatable portion is driven downward.

In one aspect, the upper rotatable portion engages the lower rotatable portion such that the upper rotatable portion and lower rotatable portion rotate together.

In one aspect, the upper stationary portion includes at least one alignment dowel extending therefrom, wherein the at least one alignment dowel is received in a corresponding alignment bore formed in the lower stationary portion.

In one aspect, the upper rotatable portion includes at least one drive pin extending downwardly therefrom, wherein the at least one drive pin is received in a corresponding drive pin bore of the lower rotatable portion.

In one aspect, the blank includes at least one aperture extending therethrough, wherein the at least one drive pin passes through the at least one aperture.

In one aspect the method includes fixing rotation of the upper rotatable portion to the lower rotatable portion prior to driving the blank downward.

In one aspect the method includes applying a downward press force on the upper rotatable portion and the upper stationary portion, wherein an upper helical mesh indexes the upper rotatable portion relative to the upper stationary portion to causes relative vertical and rotational movement between the upper rotatable portion and the upper stationary portion.

In one aspect the method includes counteracting the downward press force with an upwardly directed spring force applied to the lower rotatable portion.

In one aspect, the downwardly press force is applied to the upper stationary portion, through a bearing disposed between the upper stationary portion and the upper rotatable portion, and into the upper rotatable portion.

In one aspect, the upper stationary portion includes a first upper bearing plate and the upper rotatable portion includes a helical driven pressing plate, wherein a first lower bearing is disposed vertically between the helical driven pressing plate and the first upper bearing plate.

In one aspect, the upper rotatable portion further includes an upper bearing retainer and a first lower bearing plate, wherein the first lower bearing plate is fixed to the helical driven pressing plate and disposed between the first upper bearing plate and the helical driven pressing plate, a first upper bearing is disposed vertically between the upper bearing retainer and the first upper bearing plate, and the first lower bearing is disposed vertically between the first upper bearing plate and the first lower bearing plate.

In one aspect, the upper stationary portion includes a helical driver having first internal threads, and the upper rotatable portion includes a helical driven pressing plate having first external threads, wherein the first internal and first external threads engage to define a upper helical mesh; and, the lower stationary portion includes a helical spline forming die having second internal threads, and the lower rotatable portion includes a helical lower pad, wherein the second internal and second external threads engage to define a lower helical mesh.

In another aspect, a press assembly for defining external helical threads on a blank is provided, the press assembly including: a lower die shoe assembly configured to receive a gear blank having an unfinished condition, the lower die shoe assembly including a lower stationary portion and a lower rotatable portion rotatable relative to the lower stationary portion; an upper punch shoe assembly configured to move relative toward the lower die shoe assembly, the upper punch shoe assembly including an upper stationary portion and an upper rotatable portion rotatable relative to the lower stationary portion, wherein the upper punch shoe assembly is configured to engage the blank and shape the blank in combination with the lower die assembly; wherein the upper rotatable portion and lower rotatable portion are configured to engage each other in fixed relation for conjoint rotation; wherein the upper rotatable portion and lower rotatable portion are moveable downward relative to the upper and lower stationary portions, wherein the relative downward movement causes the conjoint rotation.

In one aspect, the upper stationary portion includes: a helical driver having first internal threads, and the upper rotatable portion includes a helical driven pressing plate having first external threads, wherein the first internal and first external threads engage to define an upper helical mesh; the lower stationary portion includes a helical spline forming die having second internal threads, and the lower rotatable portion includes a helical lower pad having second external threads, wherein the second internal and second external threads engage to define a lower helical mesh; and, the upper and lower helical mesh have the same angle.

In one aspect, the upper rotatable portion includes at least one drive pin extending therefrom, wherein the lower rotatable portion includes at least one drive pin bore corresponding to the at least one drive pin, wherein the drive pin bore receives the drive pin in response to downward movement of the upper rotatable portion to fix the upper and lower rotatable portion for conjoint rotation.

In one aspect, the helical drive pressing plate is moveable into the helical spline forming die.

In one aspect, the upper stationary portion includes a first upper bearing plate, wherein the upper rotatable portion further includes an upper bearing retainer and a first lower bearing plate, wherein the first upper bearing plate is disposed between the upper bearing retainer and the first lower bearing plate; the upper rotatable portion includes a helical driven pressing plate fixed to the first lower bearing plate, and the first lower bearing plate is disposed between the first lower bearing plate and the helical driven pressing plate; a first lower bearing is disposed vertically between the first upper bearing plate and the first lower bearing plate and a first upper bearing is disposed between the upper bearing retainer and the first upper bearing plate; the lower rotatable portion includes a helical lower pad fixed to a lower pressure pad; the stationary portion includes a lower bearing retainer fixed to an inner base plate; a second upper bearing is disposed between the lower bearing retainer and the lower pressure pad, and a second lower bearing is disposed between the lower pressure pad and the inner base plate.

DETAILED DESCRIPTION

The press assembly, its components and its operating characteristics will now be described more fully with reference to the accompanying drawings.

Referring toFIG.1, press assembly5is positioned in its starting position where it is ready for receipt of blank10. The press can be considered to be constructed of an upper portion and a lower portion, split at the point of where blank10is placed. The upper portion is a punch shoe with guide assembly20. The lower portion is a lower die shoe assembly60. Within the punch shoe with guide assembly20, there is an upper rotating tooling assembly portion40, which is allowed to rotate relative to the punch shoe assembly20. Within the lower die shoe assembly60, there is the lower rotating tooling assembly80, which is allowed to rotate relative to the lower die shoe assembly60. Operational characteristics will be described later to describe the motion, vertical and rotational, between each of these four main tooling assemblies to produce, from the blank10, a plate with a helical tooth form on the outer diameter.

With particular attention to the upper portion ofFIG.1, The punch shoe with guide assembly20comprises two main structural plates, an upper die shoe21and a drive plate25. Drive plate25can also be considered a stripper which in previous press arrangements is used to remove material that adheres to the punch. The upper die shoe21and the drive plate25are not linked together in vertical motion, but are aligned about the vertical axis via guide posts100. A plurality of upper gas springs22are positioned in the upper die shoe21and remain in contact with the top surface of drive plate25with the face of piston22A of upper gas spring22. On the bottom portion of the upper die shoe21, a pad bottoming block24and an upper bearing plate23is mounted in a fixed position to the upper die shoe21. Helical driver26is mounted to drive plate25in a fixed relationship. A helical tooth form is formed into the inner diameter of helical driver26to provide the outside diameter of the upper helical mesh35. This helical gear form has similar characteristics as the helical gear form of the final part12. For instance, the helical angle will be the same, while the minor and major spline diameters will be adjusted accordingly for appropriate stamping operation. Also positioned in helical driver26are three setup alignment dowels27(seeFIG.3). These alignment dowels27will be used to ensure a concentric alignment between the helical driver26and the helical spline forming die68(of the lower die shoe assembly) during the setup of the press tooling.

The previously described upper bearing plate23is the structural basis of the upper rotating tooling assembly components40. On the upper side of the upper bearing plate23, an upper bearing retainer41is positioned. In between the upper bearing plate23and the upper bearing retainer41, bearing51is located. This bearing51can be of any arrangement although in the figures it is shown as a multitude of ball bearings operating on grooves formed in both the upper bearing plate23and the upper bearing retainer41. In a similar arrangement, bearing52is positioned between the upper bearing plate23and lower bearing plate42. As previously described, the upper bearing plate23is a fixed component to upper die shoe21. This allows the upper bearing retainer41and lower bearing plate42, which are fixed to each other capturing bearings51and52, to rotate about the vertical axis. Helical driven pressing plate43is also fixed to retainer41and bearing plate42with fasteners (not shown), allowing a combined rotational movement. Helical driven pressing plate43includes drive pins44which protrude from the lower side. On the outer diameter of the helical driven pressing plate43, a helical spine form is provided, which is designed to mate to the helical spline form of the helical driver26to create the upper helical mesh35. Further operational characteristics between the helical driver26and the helical driven pressing plate43will be further described later in the specification.

Now moving attention to the lower portion ofFIG.1, and with additional reference toFIG.4, the components of the lower die shoe assembly60will be described. The main structural plate of the lower portion of the press, the lower die shoe62is supported by parallel supports61positioned below. The lower die shoe62is positioned about the vertical axis via guide posts100. Guide posts100ensure alignment of the upper and lower portions of the press and extend from the lower die shoe assembly60to the upper die shoe21. Attached to the lower die shoe62on the upper side is the base plate64. Further attached to the upper side of the base plate64are multiple pad balancing blocks65arranged equally around base plate64. Inward of the pad balancing blocks65, the helical spline forming die68is positioned. Helical spline forming die68is fastened and fixed to the base plate64. The parallel supports61, lower die shoe62, base plate64, and pad balancing block65can be considered one monolithic component. Helical spline forming die68, in three equal angular positions has a setup alignment bores69. This bores69will receive setup alignment dowels27when the press is closed and be used for final concentric alignment between the helical driver26and helical spline forming die68.

Still with respect to the lower portion ofFIG.1, the body of lower gas spring66is positioned and fixed in the center of the lower die shoe62. Piston66A of the lower gas spring66provides an upwards vertical force against the tooling as it is compressed, which supports the center portion of blank10and therefore final helical OD stamped part12. The body of the lower gas spring66is fixed in position to the lower die shoe62, but the piston66A extends upwards relative to the body66and provides a force on lower die shoe62. The piston66A continually applies a force, although varying during stamping operation based on the position of lower die shoe62and inner base plate63so there is always contact with the inner base plate63. Mounted above the inner base plate63with a plurality of fasteners67is the lower bearing retainer70. Note that the lower gas spring66, inner base plate63and lower bearing retainer70are fixed rotationally together as well as fixed rotationally to the lower die shoe62via an anti-rotation dowel71shown inFIG.6. These three components (gas spring66, inner base plate63, and bearing retainer70) are allowed to move vertically relative to the lower die shoe62and the base plate64. Positioned between the inner base plate63and the lower bearing retainer70is the lower pressure pad81. The lower pressure pad81is supported on the bottom by bearing91against the inner base plate63and above by bearing92against the lower bearing retainer70. These bearings91and92can be of any arrangement although in the figures it is shown as a multitude of ball bearings for bearing91with operating on grooves formed in both the inner base plate63and lower pressure pad81, while bearing92is shown as thrust washer. This bearing arrangement allows the lower pressure pad81to rotate about the lower bearing retainer70. Helical lower pad82is fixed to the lower pressure pad81resulting in the helical lower pad82and lower pressure pad81to make up the components in the lower rotating assembly80. The helical lower pad82, at the outer diameter thereof, has a helical spline form which would mesh or mate with the inner spline form of the helical spline forming die68to create lower helical mesh75. In one aspect, the lower pressure pad81is not threaded and defines a radial gap relative to the inner diameter of the spline forming die68. The helical features of the helical spline forming die68are used to properly support the blank, particularly near the outer diameter, during the stamping process to ensure good shearing of the helical tooth feature. Piloting feature85(seen in cross-section ofFIG.8) on the helical spline forming die68is used to position blank10. The helical spline forming die68also has a multitude of drive pin bores83which will receive the drive pin44of the upper portion of the press, with the drive pin also passing through aperture13of blank10. Alternative methods to the use of drive pins44will be explained later in the specification.

Referring toFIG.2, the finished helical outer diameter stamped disc12is shown. In the manufacturing process described, blank10would begin with an overall larger diameter18with a thickness16on the outer portion same as the final part. The geometric features such as the central bore and apertures13, as well as any differences in thickness or transitions may also be previously formed as the application requires. Finished part12will have a helical tooth spine portion11on the outer edge. This helical spline will have an angle15which is non-parallel to the central axis of the blank10and finished part12and is formed across the entire thickness16of the part. The helical spline angle15will be the same for each spline or tooth on the outer diameter. The helical spline angle15can vary dependent on application requirements. In this example the angle is approximately 30 degrees. The hand of the helix can be either left hand or right hand dependent on application requirements, but will be the same hand throughout a given finished part12.

Referring toFIG.3, a view of the bottom of punch shoe with guide assembly20is shown in the same operational step as seen inFIG.1. Guide posts100are fixed to upper die shoe21and passes through guide bushing46which can be adjusted to align drive plate25to upper die shoe21with the fasteners46A surrounding the guide bushing46. Fastener45is used to attach pad bottoming block24(hidden from view) to drive plate25. Helical driver26is shown fixed and piloted within a locating diameter of drive plate25. A trio of setup alignment dowels27are positioned equally around and fixed to helical driver26. The upper helical mesh35can now be fully seen, where the inner helical spline feature of helical driver26engages the outer helical spline feature of helical driven pressing plate43. The upper helical mesh35is the interface allowing relative rotation between helical driven pressing plate43and drive plate25/helical driver26(which are fixed to each other). Drive pins44are shown installed into helical driven pressing plate43.

Referring toFIG.4, a top view of the lower die shoe assembly60is shown in the same operational step asFIG.1. Guide posts100will pass through lower guide bushing105which can be adjusted to align the lower die shoe assembly60with the punch shoe with guides assembly20. Once aligned, lower guide bushing105is fixed to lower die shoe62and fastened with fasteners105A. Base plate64provides the basis for attachment and alignment of the helical spline forming die68as it is received in the base plate64diameter used to pilot the helical spline forming die68. Around the face of the base plate64, pad balancing blocks65are attached. Lower helical mesh75can be clearly seen between the inner diameter of helical spline forming die68and the outer spline82A of helical lower pad82. The lower helical mesh75is the interface allowing relative rotation between helical spline forming die68and helical lower pad82. Drive pin bores83are positioned around the face of helical lower pad82. Closer to the central axis, the lower bearing retainer70, which is stationary relative to the rotating lower pressure pad81and helical lower pad82, can be seen with fasteners67extending downward and attaching the lower bearing retainer70to inner base plate63(hidden from view), such that lower bearing retainer70, inner base plate63, and lower die shoe62are fixed.

Referring toFIG.5, press assembly5is now in the operational position just prior to beginning stamping the helical outer diameter feature to blank10. The punch shoe with guide assembly20has been brought down towards the lower die shoe assembly60. The lower rotating tooling assembly80and lower helical mesh75is in its upper most position, where helical lower pad82may be rotated relative to helical spline forming die68at interface point76. At this position blank10is fully supported across the helical lower pad82and helical spline forming die68. The upper rotating tooling assembly40at this operational position begins to contact blank10upper surface with the bottom surface of helical driven pressing plate43. In this embodiment drive pins44are shown passing through blank10via aperture13and engaging the drive pin bore83of helical lower pad42. This is to rotationally connect the upper rotating assembly40with the lower rotating assembly80as required in further operational steps. Alternatives to creating a connection between the upper rotating assembly40and the lower rotating assembly80could also be mechanical gripping features, pressure contact, or other lug features on blank10to achieve the same result of rotationally connecting each assembly and allowing helical driven pressing plate43to impart a rotation on blank10and the lower rotating tooling assembly components80. Upper rotating tooling assembly40is positioned so that there is a starting interface point36of upper helical mesh35where helical driven pressing plate43has not begun to form any feature into blank10.

Continuing to refer toFIG.5, now that the various press assemblies previously discussed are in position, a coordinated and timed stamping operation on blank10begins. Three overall forces within press assembly5are utilized to stamp blank10. The main press force110, either supplied mechanically or hydraulically, is the majority of the force utilized to shear blank10across thickness16to form the outer helical diameter11. With the application of main press force110and movement of the upper die shoe21downwards, the upper gas springs22build pressure and apply a vertical force from pistons22A directly to drive plate25and through the previously described connective nature into helical driver26. This vertical force of helical driver26is exerted, through upper helical mesh35, into helical driven pressing plate43. As there is an angularity to upper helical mesh35tooth form, a force applied vertically from helical driver26translates to a rotational indexing motion of helical driven pressing plate43. This results in the helical driven pressing plate43to extend downwards relative to interface point36and the helical driver26, pressing into the blank10. As previously described, drive pins44(or alternatively other torque transferring mechanisms) rotationally connect the upper rotating tooling assembly40with the lower rotating tooling assembly80. Therefore, rotational motion of the helical driven pressing plate43will result in an equal rotation of the helical lower pad82. The forces developed by the upper gas spring22are not solely sufficient in shearing blank10due to the thickness16and strength of the material utilized and only used, in conjunction with the upper helical mesh35, to impart a rotational motion on the rotating assemblies40and80. The lower gas spring66, due to its continual contact with inner base plate63, provides a controlled reactive upward force on the connected press components to support blank10.

Still referring toFIG.5, the force transfer of main press force110will be described. Main press force110will be applied in conjunction with the upper gas spring force22developed by compression of upper gas spring piston22A. Press force110will be applied directly to upper die shoe21, into upper bearing plate23, through bearing52, into lower bearing plate42, transferring into helical driven pressing plate43. A comparably small, additional force component111is also acting on helical driven pressing plate43due to the force from a compression of upper gas spring piston22A onto the drive plate25and the helical driver26, translating through the upper helical mesh35this downward vertical component of force. This combined force115is partially counter acted by lower gas spring force112due to the displacement of lower gas spring piston66A. As stamping of blank10occurs, the upper rotating tooling assembly40and the lower rotating tooling assembly80will rotate equivalent to the designed helix angle15of the final part12. This rotation is relatively small based on helix angle15and could also be considered indexing motion. The rotating tooling assemblies40and80will travel downward vertically based on helix angle15and blank thickness16. Helical driven pressing plate43will travel beyond interface point36, resulting in the bottom surface of helical driven pressing plate43being positioned below, or extended away from, the bottom surface of helical driver26. Similarly, helical lower pad82will rotate resulting in a downward position relative to its starting point at interface point76between the helical lower pad82and helical spline forming die68. During full travel, the cutting edge43B of helical driven pressing plate43will pass helical spline forming die edge68B to provide a clean break across entire thickness16. It is an advantage to utilize the tooling components of helical driver26, helical driven pressing plate43and helical spline forming die68with same helical features as final part12instead of providing an externally rotating input, such as an electric motor driving rotating assemblies40and80or other mechanically driven linkages, as the timing of applying forces to stamp teeth11while ensuring the correct helix angle15would be very difficult. These external rotating inputs would also add cost and complexity to the process.

Referring toFIG.6, an isometric sectional view of press assembly5is shown in a fully traveled position at the end of forming final part12from blank10. Of particular interest in this view is anti-rotation dowel71which is fixed in position to the inner base plate63. A bushing72is fixed to a bore within lower die shoe62. Anti-rotation dowel71inserts into bushing72to ensure no rotation occurs between the inner base plate63and lower die shoe62. As lower rotating components60and gas spring piston66A travel vertically, anti-rotation dowel71will remain in engagement with bushing72and lower die shoe62providing a reactive rotational moment to the rotating components60and support bearings91and92.

Referring toFIG.7, a view of the helical driven pressing plate43and helical spline forming die68are shown in a position as seen in the same operational step asFIG.1. Blank10, not shown, would be positioned therebetween. Final part12will have a design helical angle15, while helical spline feature43A and68A will have the same corresponding angle15′. This ensures the stamping process produces a final part12with the correct and accurate geometry. Helical driven pressing plate43will rotate and engage into helical spline forming die68while stamping a helical spline of the same design features (i.e. helical angle, minor and major outer diameters) as the final part12using the outer helical spline feature43A of helical driven pressing plate43. Cutting edge43B will be pressed into, therefore shearing blank10against edge68B during the downward rotating travel. Cutting edge43B can be a sharp edge or a radiused edge depending on the result of the stamping procedure. The overall travel of cutting edge43B relative to68B will be sufficient to ensure the complete thickness16of blank10is formed, slightly entering the internal diameter68B and past edge68B completing the stamping or shearing of material from the blank10. Diametrical clearances between helical spline tooling feature68A and43A can be adjusted to ensure a clean shear with minimal burnish, fracture, and rollover characteristics on the helical spline tooth11of final part12.

Referring toFIG.8, a detailed sectional view of press5in its position at full travel is shown. At this point upper gas spring piston22A is compressed against the drive plate25due to the decreased distance between the upper die shoe21and the drive plate25. Lower gas spring piston (not shown) is pushed downward as the upper and lower rotating tooling assemblies40and80have reached their full rotation downward based on helix angle15. Helical driven pressing plate43has entered into helical spline forming die68traveling fully across thickness16to stamp the helical spline teeth11forming final part12from blank10. Outer diameter trim scrap14can now be seen squeezed between the helical driver26and helical spline forming die68. At this point press force110is reduced. Lower gas spring force112results in force applied to the lower pressure pad82, resulting in the pressure pad rotating now in a reversed rotation and traveling vertically upwards due to the lower helical mesh75, similar to how the helical driver26drove the helical driven pressing plate43prior to forming final part12. The reverse rotation of the lower rotating assembly80, plus final part12rotating out of the inner diameter of the helical spline forming die68, also drives a reversed rotation into the upper rotating tooling assembly40due to drive pins44. At the position where the helical spline forming die68and the helical lower pad82have returned to interface point76(and corresponding interface point36for helical driver26and helical driven pressing plate43), the press can further open where punch shoe with guide assembly20and the upper rotating tooling assembly40can be retracted. This allows final part12to be removed and the outer diameter trim scrap14to be discarded. At this point a new blank10can be reloaded and the process can repeat.