Vehicular applications for magnetorheological fluids

Lord Corporation believes that magnetorheological (MR) technology is building on its acceptance in the automobile industry for improving operator safety, ergonomics and comfort for agricultural machinery.

Looking at the automotive OEMs and their selection of MR technology shows that the technology delivers. Automotive marques such as Cadillac, Chevrolet, Buick, Ferrari, Honda, Holden and others have integrated Lord MR technology into their primary suspension systems. A case in point is Audi. When Audi's new TT was unveiled in 2006, it included a performance boost because of the selection of Delphi Corporation's MagneRide semi-active suspension system, which incorporates Lord's MR fluid technology. The system provides continuously variable real-time suspension damping control. Named 'Audi Magnetic Ride' on the TT, MagneRide responds in real time to road and driving conditions based on inputs from sensors that monitor the vehicle body and wheel motion.

Lord MR technology is based on a proprietary and patented fluid. When exposed to a magnetic field, MR materials change state nearly instantaneously and with complete reversibility. As a result, MR technology provides fast and infinitely variable control of energy dissipation for industrial and automotive devices. This damping power produces – according to OEM desire – a more comfortable feel or sportier vehicle handling. Audi uses the magneto-rheological dampers for both ride comfort and handling improvement. In its driver-selectable comfort mode, the suspension allows for a more isolated vehicle feel; in sports mode, the vehicle offers a sportier ride and more precise steering control.

Seat suspension

Devices and systems using Lord's MR technology are now proven in other vehicular applications, including driver's seat suspension in off-highway, construction and agricultural equipment, and steer-by-wire operator control in industrial and marine vehicles. Lord says it is the only provider of commercial MR fluid, and the company holds more than 100 global device and fluid patents in the MR field. More than 500,000 devices have been produced using LORD MR technology.

One example of the application of Lord MR technology to the agriculture market is through products offered from Sears Manufacturing Company – a global manufacturer of suspension and non-suspension seating for agricultural, construction and earthmoving equipment. According to Anthony Glick, Global Marketing Manager, Off-Road Division for Sears Manufacturing, the company applied the technology to its seats in a custom offering to the agricultural and off-highway equipment market, where it works well because the inputs to operators in these environments are so much larger.

Glick says: "The agricultural equipment industry especially is very keen on technology that improves operator environment. Larger pieces of equipment are doing increasing levels of work. Enhanced suspension isolation enables operators to spend longer hours at the controls and to work at higher speeds, and our products support that drive toward greater productivity."

The development of these systems also supports the trend, as evidenced by Physical Agents Directive (PAD) regulations in Europe, toward reducing the shock and vibration doses that operator's experience.

Doug LeRoy, Market Manager for Lord MR Solutions, comments: "Sears Seating ranks among the premier companies in this industry, and we are excited to have our technology incorporated into its products. The system provides a 40 per cent reduction in vibration to the operator."

Air suspension vehicle seat

For example, farm equipment manufacture CNH offers the Sears Seating's 5095 VRS seat on new, large row crop tractors, marketed under the trade names Positive Response (Case IH) and AutoComfort (New Holland). The 5095 VRS (Vibration Reduction System) is said to be the first air suspension vehicle seat that combines semi-active damper technology, exclusively marketed and developed by Lord Corporation, with a low natural frequency (LNF) air spring system, developed by Sears Seating, to provide superior vibration isolation during normal vehicle operation while maintaining excellent ride control during rough terrain inputs. Unlike standard agricultural seats, which compromise shock and vibration control, the VRS 2000 with the MR-enabled system automatically adapts to both the driver's body weight and continually changing levels of shock and vibration, improving operator productivity while reducing fatigue.

Glick says: "The agricultural equipment industry is very interested in technology that improves the operator environment. Larger pieces of equipment are doing increasing levels of work. Enhanced suspension isolation enables operators to spend longer hours at the controls and to work at higher vehicle speeds. As such, products that employ high technology are needed to support the drive toward greater productivity."