Method of reducing the impact speed of an armature in an electromagnetic actuator
AssigneeFEV Motorentechnik GmbH & Co. Kommanditgesellschaft
InventorsGuenter Schmitz, Martin Pischinger, Thomas Goebel, Michael Schebitz, Ekkehard Schrey
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Abstract
A method is provided for reducing an impact speed of an armature on a pole face of an electromagnet in an electro-magnetic actuator, in which the armature moves toward the pole face against a restoring spring force when the coil of the electromagnet is charged with current. The method includes limiting a voltage applied to the coil to a predeterminable maximum value as the armature approaches the pole face so that a current flowing through the coil drops for a portion of the time of the voltage limitation.
Claims20
A method for reducing an impact speed of an armature on a pole face of an electromagnet in an electromagnetic actuator, in which the armature moves toward the pole face against a force of a restoring spring when a coil of the electromagnet is charged with a current, comprising:
- limiting a voltage applied to the coil to a predeterminable maximum value when the armature approaches the pole face so that due to a voltage additionally induced across the coil in the last phase of armature approach to the pole face the current flowing through the coil drops for a portion of the time of the voltage limitation just prior to armature impact.
An electromagnetic actuator comprising:
- an armature having a face;
- an electromagnet having a coil and a pole face opposite the face of said armature;
- a restoring spring coupled to said armature for applying a force against said armature when the face of said armature moves towards the pole face of said electromagnet;
- a circuit for applying a voltage and a current to the coil of said electromagnet to move the face of said armature toward the pole face of said electromagnet;
- and
- a limiting circuit for limiting the voltage applied to said coil to a maximum value when the face of said armature approaches the pole face of said electromagnet, such that due to a voltage additionally induced across said coil during a final approach of the face of said armature towards the pole face of said electromagnet, the current flowing through said coil decreases for a portion of time just prior to armature impact, thereby reducing an impact speed of the face of said armature on the pole face of said electromagnet.
Dependencies are inferred from the claim text.