Valve for a magnetorheological liquid

#The present invention relates to a valve for a magnetorheological fluid, with a flow duct, with regard to which the through flow of the magnetorheological fluid through the flow duct can be varied by means of a magnetic field acting upon the flow duct. The flow resistance through the flow duct and consequently the through flow through the valve are influenced appropriately by the magnetic field.

#Magnetorheological fluids are usually composed of a suspension of small ferromagnetic particles, such as, for example, carbonyl iron powder, which are finely distributed in a carrier fluid. The particles typically have diameters of between 0.1 and 50 micrometers and form chain-like structures under the influence of a magnetic field, so that the viscosity of the magnetorheological fluid increases considerably under the influence of a magnetic field. The change in viscosity takes place in this case very quickly in the range of a few milliseconds or less and is entirely reversible.

#Essential advantages of a valve with a magnetorheological fluid are very rapid switching times in the range of a few milliseconds or less and the possibility of dispensing with moved mechanical elements.

#In the Figures:

#FIG. 1 shows a diagrammatic illustration of a valve according to the invention;

#FIG. 2 shows a diagrammatic time graph of the magnetic field strengths during magnetic reversal;

#FIG. 1 shows a highly diagrammatic illustration of a valve 1 according to the invention. So that functioning can be illustrated more clearly, magnetic flux lines 6, illustrated as vectors, have been depicted.

#In the region of the flow duct 2, the magnetic field 9 of the magnet or magnetic device 7 can act upon the magnetorheological fluid 12. In the magnetic field 9, the particles 30 of the magnetorheological fluid 12 are oriented and form chains, with the result that the viscosity of the fluid increases. The viscosity can be set, as desired, in a wide range via the strength of the effective magnetic field 9.

#The shear stress which the magnetorheological fluid 12 can build up is also dependent upon the magnetic field 9. If the pressure difference in the flow duct 2 is lower than the shear stress, flow is prevented. Up to this limit, the valve 1 blocks the through flow of the magnetorheological fluid 12.