(19)
(11) EP 0 354 682 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
14.11.1990 Bulletin 1990/46

(43) Date of publication A2:
14.02.1990 Bulletin 1990/07

(21) Application number: 89307588.7

(22) Date of filing: 26.07.1989
(51) International Patent Classification (IPC)5: B21C 23/18, B21K 1/30
(84) Designated Contracting States:
DE FR GB

(30) Priority: 08.08.1988 US 229405

(71) Applicants:
  • FORD MOTOR COMPANY LIMITED
    Brentwood, Essex CM13 3BW (GB)

    GB 
  • FORD-WERKE AKTIENGESELLSCHAFT
    D-50725 Köln (DE)

    DE 
  • FORD FRANCE S. A.
    F-92506 Rueil-Malmaison Cédex (FR)

    FR 

(72) Inventor:
  • Fuhrman, William James
    Bloomfield Hills Michigan 48013 (US)

(74) Representative: Messulam, Alec Moses et al
A. Messulam & Co. 24 Broadway
Leigh on Sea Essex SS9 1BN
Leigh on Sea Essex SS9 1BN (GB)


(56) References cited: : 
   
       


    (54) Cold extrusion process for internal gear teeth


    (57) A cold extrusion process for forming internal gear teeth comprising machining an internal ring gear blank (58) with precision internal and external diameters, mounting the ring on a pilot diameter of a mandrel (62) on which is formed external die teeth (70) having a metal forming region, a metal guiding entrance region and a tapered metal flow exit region, mounting a support ring (68) around the mandrel (62) and the workpiece (58) and pressing the workpiece through the support ring and through the die teeth (70) in sequential steps, the initial step resulting in formation of internal teeth in the workpiece (58) for a substantial axial length of the workpiece and the following step resulting in forcing a subsequent blank against the workpiece (58) by the press (64) which results in full internal tooth formation, the finished gear being removable as the support ring (68) and mandrel (62) are retracted to the original position and as a subsequent workpiece is loaded on the pilot diameter of the mandrel (62).







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