Brake booster with electromagnetic actuation unit

摘要

A brake booster (10) for a vehicle brake system comprises a housing (12) which is divided, by means of at least one movable wall (14), into a vacuum chamber (18) and a working chamber (16). A control valve arrangement (20), which is associated to the brake booster (10) and which optionally connects the working chamber (16) to atmospheric pressure or to a vacuum, comprises a control valve housing (21) which is connected to the movable wall (14) for joint relative movement with respect to the housing (12). An electromagnetic actuation unit (26) is received in the control valve housing (21), said actuation unit having a solenoid coil (44), a magnet armature (28) operating against the spring bias and which is rigidly coupled to a first valve seat (32) of the control valve arrangement (20), and an armature counter-element (46). For improving the magnetic flux in the electromagnetic actuation unit (26) while simultaneously reducing the number of parts, an insert (92) made of diamagnetic and preferably lightweight. material extends through the armature counter-element (46), said insert (92) forming a guide (94) for an actuating piston (64) and protruding somewhat out of the armature counter-element (46) in the direction of the magnet armature (28).