Helical spline forming

Patent metadata

Field	Value
Publication number	US-9393604-B2
Application number	US-201313933711-A
Country	US
Kind code	B2
Filing date	Jul 2, 2013
Priority date	Jul 5, 2012
Publication date	Jul 19, 2016
Grant date	Jul 19, 2016

Abstract

A flow-forming machine and method for forming a final part having helical splines. The flow forming machine is provided with a stripper plate for removing the final part having the helical splines therein from the mandrel and a thrust bearing is located between the stripper plate and the final part during stripping of the final part from the mandrel to allow relative motion between the stripper plate and the final part to successfully strip the final part from the mandrel without damaging and while maintaining the integrity of the helical splines of the final part. The ejector driver and mandrel may be rotated in either direction to help in successfully stripping the final part from the mandrel.

First claim

What is claimed is:

1. A system for removal of a flow formed final part having at least one helical spline, the system comprising:
a mandrel rotatable about an axis and having an outer shape against which a pre-form is flow formed into the final part having at least one helical spline;
a stripper plate for imparting an axial force on the final part during removal of the final part from the mandrel;
a thrust bearing located between the stripper plate and the final part for allowing relative movement between the final part and the stripper plate during removal of the part from the mandrel; and
an ejector driver disposed in abutting relationship with the final part and axially movable and rotatable along the axis to impart a rotational force on the final part simultaneously with the axial force imparted by the stripper plate during the removal of the final part from the mandrel.

2. The system of claim 1 , wherein the system includes a mandrel main adapter which is selectively rotatably coupled to the final part and can rotate the final part during removal of the final part from the mandrel.

3. The system of claim 2 , wherein the ejector driver is rotatable in sync with the mandrel in either a clockwise or a counter-clockwise direction during removal of the final part from the mandrel.

4. The system of claim 3 , wherein the ejector driver and mandrel are operably configured to rotate in a direction opposite of the helical spline while the final part operably engages the stripper plate to unthread the final part from the mandrel.

5. The system of claim 1 , wherein the system further comprises a matching form feature provided on the ejector driver, the matching form feature operably shaped and configured to engage against an inner diameter of the pre-form and final part and impart the rotational force, in addition to the second axial force, during removal of the final part.

6. The system of claim 5 , wherein the ejector driver includes an ejector driver head defining the matching form feature for engaging the pre-form and final part.

7. The system of claim 6 wherein the matching form feature is a hexagonal shape.

8. The system of claim 1 , wherein the thrust bearing has a first side located proximal an opening to the stripper plate and coupled to the stripper plate and a second side for engaging a surface of the final part to impart the first axial force during removal from the mandrel.

9. The system of claim 8 , wherein the second side of the thrust bearing has a roughened surface for preventing relative movement between the second side and the final part during removal of the final part from the mandrel.

10. The system of claim 1 , wherein the final part is a one-piece final part, including a plurality of said at least one helical spline that are equally spaced, flow formed internal helical splines.

11. A process for forming and removing a final part including a plurality of helical splines comprising the steps of:
providing a thrust bearing located against a stripper plate for creating a stop for selective engagement against the final part;
loading a pre-form on a mandrel having an outer shape against which the pre-form is flow formed into the final part having a plurality of helical splines;
forming the pre-form onto the mandrel and flow forming the plurality of helical splines therein to obtain the final part;
axially moving and rotating an ejector driver to impart a rotational force on the final part; and
engaging the final part with the thrust bearing simultaneously with the imparted rotational force of the ejector driver, the thrust bearing located between the stripper plate and the final part to allow relative movement while applying a predetermined sufficient force to remove the final part from the mandrel without damaging the plurality of helical splines of the final part.

12. The process of claim 11 , further comprising providing an ejector driver head and an axially retractable and rotatable tailstock assembly comprising a tailstock head, said tailstock head engaging the pre-form and ejector driver head and securing the pre-form during forming.

13. The process of claim 12 , further comprising providing a mandrel adaptor that is rotatable, and selectively rotating said tailstock assembly and said mandrel adaptor in unison during flow forming the pre-form for simultaneous rotating the mandrel and pre-form.

14. The process of claim 13 , further comprising providing a plurality of rollers that are retractable and rotatable pressure rollers, said plurality of rollers applying a predetermined amount of pressure to force the pre-form against the mandrel and simultaneously axially and radially forming a predetermined desired geometry of the pre-form in forming the final part.

15. The process of claim 14 , further comprising moving the plurality of rollers and the tailstock assembly to a retracted position while the final part remains on the mandrel prior to removal.

16. The process of claim 11 , wherein the plurality of helical splines match those of the mandrel creating an interference fit and said predetermined sufficient force for removing the final part from the mandrel is about 2175 psi.

17. The process of claim 11 , wherein the ejector driver is configured to rotate the mandrel in either a clockwise or a counter-clockwise direction during forming and/or removal of the final part, and said rotating of the ejector driver occurs in a direction opposite of the plurality of helical splines while the final part operably engages the stripper plate to unthread the final part from the mandrel.

18. The process of claim 11 , further comprising providing a matching form feature on the ejector driver configured to engage with the final part and impart the rotational force in addition to an axial force during removing of the final part from the mandrel.

19. The process of claim 11 , wherein broaching or hobbing processes are not used.

20. A process for forming and stripping a final part including a plurality of helical splines comprising the steps of:
providing a plurality of rollers;
providing a mandrel having an outer shape against which a pre-form is flow formed into the final part including a plurality of helical splines;
loading the pre-form on the mandrel;
providing an axially retractable and rotatable tailstock assembly comprising a tailstock head for engaging the pre-form and securing the pre-form during forming;
providing an ejector driver configured to rotate in sync with the mandrel in either a clockwise or a counter-clockwise direction during forming and removal of the final part;
forming the pre-form onto the mandrel and flow forming said plurality of helical splines therein to obtain the final part;
rotating the ejector driver and the mandrel in sync and in a direction opposite of the plurality of helical splines while the final part operably engages a stripper plate to unthread the final part from the mandrel; and
axially moving the ejector driver during said rotating of the ejector driver and the mandrel to impart a rotational force on the final part;
engaging the final part with the stripper plate including a thrust bearing located between the stripper plate and the final part simultaneously with the imparted rotational force of the ejector driver to allow relative movement while applying a predetermined sufficient force to remove the final part from the mandrel without damaging the plurality of helical splines of the final part.

Assignees

• Magna Powertrain Usa Inc

Inventors

• Abbassian Bahman
• Christiansen Lisa

Classifications

• B21D22/16 Primary

  over shaping mandrels or formers · CPC title

• B21C35/02 Primary

  Removing or drawing-off work · CPC title

• B21D53/28

  gear wheels · CPC title

• B21D45/02

  Ejecting devices · CPC title