An upper-bound analysis for the forging of spur gears

The forging of spur gears has been investigated by means of upper-bound ana lysis. A kinematically admissible velocity field for the forging of spur ge ars has been newly proposed; especially, a neutral surface has been introdu ced into the forging of gears by using hollow billets with a flat punch. Th e half pitch of the gear has been divided into seven deformation regions. B y using the kinematically admissible velocity field, the power requirements and suitable conditions for the forging of spur gears were successfully ca lculated by a numerical method. As a result, (i) for reducing the forging l oad, the use of a hollow billet is more effective than a solid billet; (ii) for increasing the dimensional accuracy of forged gears, punch with a mand rel is desirable; (iii) the radius of the neutral surface and the inner rad ius approach zero as the height reduction increases; (iv) a suitable number of teeth for the forging of a spur gear was found to be between 15 and 20; (v) for the dimensional accuracy of forged gears, it is necessary to deter mine the elastic deformation of die and workpiece, the clearance between th e die and punch, etc. (C) 2000 Elsevier Science S.A. All rights reserved.