Patent EA-000339-B1 (EA)
Title: Apparatus and method for forging a pinion gear with a near net shape
Inventor: DOUGHERTY MICHAEL C
IPC: B21K1/30
Filed: 1996-10-31
Abstract: 1. An improved die apparatus for forging a solid workpiece (16) having a head portion (16A) and a stem portion (98) into a forged gear (90) having a near net shaped head portion (92), said die apparatus comprising: a) a first die (22,122) and a second die (80, 180), wherein said first and second dies (22, 122, 80, 180) being selectively moveable relative to each other, said first die (22, 122) having a tooth die (26, 126) with a negative cavity (27, 127) therein corresponding to said near net shaped head portion (92) to forge said head portion (16A); and b) an axial restriction member (99, 199) located in at least one of said first and second dies (22, 122, 80, 180) and configured for assisting in removing the near net shaped head portion (92) from said negative cavity(27, 127). 2. The die apparatus of Claim 1, wherein said axial restriction member (99, 199) is configured to permit radial movement of said forged gear (90) as first die (22, 122) moves away from relative to said second die. (80, 180). 3. The die apparatus of Claim 2, wherein said second die (80, 180) comprises a stem die (82) having an interior surface, said stem die is configured to receive said stem portion (98) of the solid workpiece (16), said stem portion having a surface (85), said axial restriction member (99, 199) comprises a structure (85, 99) configured for providing axial resistance between the surface (98A) of said stem portion (98) and said interior surface (85). 4. The die apparatus of Claim 3, wherein said axial restriction member (99) comprises a holding band (89) that includes a depression formed in said interior surface (85) for forming a stem protrusion (98B) on said surface (98A) of said stem portion (98). 5. The die apparatus of Claim 4, wherein said depression extends substantially around the entire periphery of said interior surface (85). 6. The die apparatus of Claim 4, wherein said holding band (89) includes at least two depressions formed in said interior surface (85). 7. The die apparatus of Claim 4, said depression (89) having a depth from about 0.254 mm to about 0.508 mm. 8. The die apparatus of Claim 4, wherein said stem die (82) has a plurality of portions (86, 87 and 88), each of said portions having a different effective outer diameter, and said holding band (89) is provided in the portion (86) with the largest effective outer diameter. 9. The die apparatus of Claim 4, further comprising a means (86) for removing said stem protrusion (98B). 10. The die apparatus of Claim 1, wherein said axial restriction member (199) is provided in said first die (22). 11. The die apparatus of Claim 10, wherein said first die (22, 122) has a tooth die (26, 126) with a bore hole (129), and a pin slidably receivable through said bore hole, said pin being selectively extendable through said bore hole to maintain engagement substantially against said near net shaped head portion (92) as said tooth die (126) moves away from relative to said second die (180). 12. The die apparatus of Claim 1 wherein said axial restriction member (99, 199) is located in said first and said second dies (22 and 80). 13. An improved method for producing a forged gear (90) having a near net shaped head portion (92) and a stem portion (98) from a solid workpiece (16), comprising the steps of: (a) providing a press machine (20, 120); (b) forging the head portion (16A) of the solid workpiece (16) with said press machine (20, 120) into the near net shaped configuration (92); (c) restricting an axial movement of said forged gear (90); and (d) removing said forged head portion (92) from said press machine (20, 120). 14. The method of Claim 13, further comprising the step of restricting axial movement of said forged gear (90) while permitting radial movement of said forged gear (90). 15. The method of Claim 13, further comprising the steps of: (e) providing a press machine (20, 120) having a first die (22, 122) and a second die (80, 180); and (f) applying a resistance to said stem portion (98) of said forged gear (90) to restrict axial movement of said forged gear (90) while permitting rotational movement of said forged gear (90). 16. The method of Claim 14, further comprising the step of: (h) providing a press machine (20, 120) having a first die (22, 122) and a second die (80, 180), said first die (22, 122) including a tooth die (26, 126) with a bore hole (129), and a pin (150) selectively slidably extendable through the bore hole (29); (j) engaging said pin (150) against said head portion (92)of said forged gear (90); and (k) moving said tooth die (126) away from said forged gear (90) relative to said second die (80, 180). 17. An improved method for producing a forged gear (90) having a near net shaped head portion (92) and a stem portion (98) from a solid workpiece (16), comprising the steps of: (a) providing a die apparatus (20, 122) having a first die (22, 122) and a second die (80, 180), said second die (80, 180) having a stem die (82) with a holding band (89) provided in the interior surface (85) of said stem die (82); (b) forging the near net shaped head portion (92) of said workpiece (16) with said die apparatus (20 120); (c) forging a stem protrusion on said stem portion (98) in said holding band; and (d) removing said near net shaped head portion (92)from said die apparatus (20, 120). 18. The method of Claim 17, comprising the step of substantially restricting axial movement of said forged gear (90) while permitting radial movement of said forged gear (90). 19. The method of Claim 17, comprising the step of removing said forged gear (90) from said second die (80, 180). 20. The method of Claim 17, comprising the step of removing the stem protrusion (98) from the stem portion (98B).