METHOD AND DEVICE FOR FORMING UNIVERSAL JOINT

摘要

PURPOSE:To form a center groove to an exact position with high accuracy by coining the groove on the inside peripheral face in the cup part of a stock by a mandrel at the bottom dead point of the stroke of an upper die and coining the center groove to the bottom of the cup part by an ascending center mandrel. CONSTITUTION:The cup part 6a of the stock 6 is put on the mandrel 7 and the center mandrel 21 and is housed into a lowder die 5. A stationary cam 13 descends when the upper die 12 is lowered thereafter. A stationary cam 13 is then lowered and a punch 14 is moved by a cam face 13 toward the bore of the stock 6 to press the outside peripheral face 6c of the cup part 6a. The groove is thus coined on the inside peripheral face 6b of the cup part 6a by the mandrel 7. A back pressure is applied to the rear face 6d of the cup part 6a of the stock 6 by a work holder 15 controlled by a hydraulic cylinder 17 at this time. The center mandrel 21 is risen by a hydraulic mechanism at the bottom dead point of the stroke of the upper die 12, by which the center groove is coined to the bottom part 6e of the cup part 6a cooperatively with the back pressure to be applied by the work holder 15 to the rear face 6d of the cup part 6a.