METHOD OF MAKING AN ELECTROMAGNETIC COUPLING DISC

摘要

A coupling disc (20) (i.e. the armature or rotor) of an electromagnetic coupling is made by using a punch and die to emboss a plurality of radially spaced rows of angularly spaced grooves (32) in the non-working face (24) of the disc (20) and to cause a plurality of radially spaced rows of angularly spaced projections (41) to be displaced from the working face (25) of the disc (20). The working face (25) then is machined to remove the projections (41) and, as an incident thereto, circumferentially continuous grooves (45) are formed in the working face (25) in radial alignment with the grooves (32) in the non-working face (24) in order to leave thin webs (46) which establish magnetic flux barriers. To establish even better flux barriers, angularly spaced slots (50) of the narrow radial width may be formed through the disc (20) by piercing the disc (20) from the working face (25) thereof and breaking through the thin webs (46) located between the sets of grooves (32,45).