Positive search report for the magnetorheological damper patent application

Our patent application for the development of a magnetorheological semi-active damper system was filed under general document number 2013-G-377377 and entered the Turkish Patent Institute records under application number 2013/12816. The positive search report was notified to us by the Turkish Patent Institute’s letter number 144576 dated 30 March 2016.

How the magnetorheological fluid works

In the damper system covered by the application, a magnetorheological smart fluid takes the place of the oil and oil derivatives used in passive dampers. The fluid is a combination of pure iron particles 3–10 microns in diameter with a carrier liquid — mineral or synthetic oil, water, or glycol. Additives keep the iron particles from settling and prevent metal wear.

With no external influence on the fluid, the iron particles sit in random positions and the fluid behaves as a Newtonian liquid. Under a magnetic field the randomly positioned solid particles line up along the field and form a chain structure. That chain structure acts as a sieve and impedes the passage of the fluid through the region; the internal resistance to flow makes the liquid behave as a fluid of much higher viscosity.

Under a magnetic field the smart fluid moves between free flow and a semi-solid state, bidirectionally and instantaneously, at a controlled yield stress. In proportion to the strength of the applied field, the yield stress reaches 100 kPa within milliseconds. The magnetic polarisation mechanism is unaffected by temperature, so the system works across a very wide temperature range.

Objectives of the application

The magnetorheological semi-active damper system covered by the application was developed with the following objectives:

• To meet ideal performance requirements with dampers that use magnetorheological fluid.
• To deliver an efficient, predictable, precise and powerful damping effect while reducing the size of the damper system.
• To obtain a damper system whose damping force can be controlled ideally.
• To increase the performance of the magnetorheological damper.
• To shorten the damper piston and lengthen the piston travel.
• To make the damping force linear.
• To let the system produce different damping forces in compression and in extension.
• To obtain a system in which the yield stress of the magnetorheological fluid can be varied continuously.

The system adds value in the automotive and medical industries wherever vibration control and shock absorption are needed, and it is of strategic importance in aerospace and defence.

The same project won two awards in a competition held by METU Technopolis: New Ideas New Business awards.