Method of operating a valve with a magnetorheological fluid

Abstract

A valve for a magnetorheological fluid is formed with a duct through which the magnetorheological fluid can flow and which can be exposed to a variable magnetic field such that the flow resistance of the duct can be set using the magnetic field in the duct. The magnetic field can be lastingly generated using a magnet device that is made at least in part of magnetically hard material. The magnetization of the magnet device can be lastingly modified by a magnetic pulse of a magnetic field generation device in order to lastingly change the magnetic field in the duct and thus the flow resistance of the duct. A valve of the invention requires energy only to change settings while a specific setting can be lastingly maintained without supplying energy.

1 . A method for operating a valve, the method comprising:
 providing at least one flow duct for conducting magnetorheological fluid therethrough;   generating a permanent magnetic field with a magnetic device, the magnetic field acting upon a magnetorheological fluid in the at least one flow duct; and   lastingly varying the magnetic field of the magnetic device by generating at least one magnetic pulse with a magnetic field generation device.   
     
     
         2 . The method according to  claim 1 , which comprises generating the magnetic pulse or pulses shorter than 100 milliseconds. 
     
     
         3 . The method according to  claim 1 , which comprises generating a pulse with a field strength sufficient to magnetize hard-magnetic parts of the magnetic device up to a magnetic saturation thereof. 
     
     
         4 . The method according to  claim 1 , wherein a shape and strength of the magnetic field of the magnetic device is lastingly variable by at least one magnetic pulse from the magnetic field generation device. 
     
     
         5 . The method according to  claim 1 , wherein the magnetic field generation device comprises at least two separately activatable coils. 
     
     
         6 . The method according to  claim 1 , which comprises demagnetizing the magnetic device by generating a damped magnetic alternating field composed of pulses with changing polarity and with decreasing strength or by way of at least one magnetic pulse. 
     
     
         7 . The method according to  claim 1 , which comprises determining, with one or more sensors, a magnetization of the magnetic device, and utilizing signals from the one or more sensors by a control device in order to determine a strength of the magnetic pulses to be generated.