Electromagnet actuator with moulded encapsulating body e.g. for ventilation valve

摘要

The electromagnet actuator has a coil located on a former (2) with connections brought out axially to the end. Located around the coil is a ferrite yoke. The assembly is moulded into an encapsulating housing. Within the former is a guide tube (6) for the armature that moves axially. The guide tube is cylindrical in cross section whereas the inner surface of the former is produced with a wavy (10) surface such that contact occurs at points around the periphery. After moulding the external housing shrinkage occurs to achieve a tight fit and so securely clamp the armature guide tube.