GB1473182A - Electromechanical transducers - Google Patents

Abstract

1473182 Inductors; electromagnets; electromagnetic relay ROBERT BOSCH GmbH 17 May 1974 [19 May 1973] 21956/74 Headings HIT H1N and HIP An electromechanical transducer comprises an electrical coil assembly, wherein a coil 11 wound on a non-magnetic plastics former 14 is surrounded by a jacket 15 of an electrically insulating plastics material containing magnetic material, and a movable magnetic member, co-operating with apparatus operable externally of the transducer, for at least partially bridging the active air gap in the flux path. In a pulse transmitter the coil has a magnetic core 12 of ferrite, soft iron, or an electrically insulating plastics material containing soft iron, and is supplied with 70 mA D.C. by cable 18 and connection 17. The rotating pin 13 induces voltage pulses of 2 to 3 V on an applied voltage of 4 V and the transmitter may be used for determining top dead centre of an internal combustion engine. In a further embodiment the transducer forms part of a relay (Fig. 2, not shown) the hinged armature (37) actuating relay contacts (34, 35). In a still further embodiment the transducer forms part of an electromagnetic actuator (Fig. 3, not shown) in which the core (45) forms the movable armature in a guide sleeve 46, an axial air gap (49) of variable length being provided between the end of the core and the magnetic plastics jacket (43) surrounding an end of the coil. The plunger 47 may be used for actuating valves or locking mechanisms on motor vehicle doors.