Magnetorheological Fluid Control Valve

Megetorhelogical fluid-based control valves provide flow control by varying electrical current to an electromagnet that affects the apparent viscosity of the magnetorheological (MRF).  Increased electric current provides an increased magnetic field, which in turn, increases the apparent viscosity of the fluid.  Therefore, the flow rate through the valve can be controlled.

The current state-of-the-art in MRF valve technology relies on strict manufacturing tolerances and additional mechanical assembly features that limit the practical application for a broad use in hydraulic systems.  Designs that require electromagnetic solenoid locations close to the MRF valve region can make manufacturing and assembly costs prohibitive and prone to maintenance complications.  MRF valves that require additional springs, pistons, and seals present additional potential valve wear induced failures.


UNR researchers have designed a low power magnetorheological (MRF) annular valve design for various engineering applications. This device can be used in many hydraulic and damper applications where flow control is desired. The device can work in series or in parallel to a fluid system, internally or externally. MRF devices require a magnetic field or circuit to change the fluid's apparent viscosity which intern will control the flow rate through the device. The invention facilitates a compact design that requires low electrical input current through a unique configuration of materials and geometry. An MRF valve was developed and tested that revealed the design benefits of this device. The invention can incorporate fail-safe characteristics for damper and other applications. The embodiment of the present invention pertains to hydraulic applications where a controllable valve changes its flow characteristics by means of a magnetic field interaction with a magnetorheological fluid (MRF).


The applications for this device exist in the areas of vibration control and energy dissipation through the controllable characteristics of the invention incorporated into a damper design either externally of internally. The invention provides a means for controlling MRF flow in hydraulic systems and dampers.  Devices that could use this invention include shock absorbers for automobiles, bicycles, motorcycles, and protective devices used for energy mitigation for large structures, such as buildings and bridges.

Magnetorheological Fluid Device
Patent No. US 6,823,895
Patent Information:
For Information, Contact:
Dan Langford
Technology Commercialization, Manager
University of Nevada, Reno and Desert Research Institute
Gregory Hitchcock
Faramarz Gordaninejad