Fewer Parts, Higher Efficiency

DN Staff

September 8, 2003

4 Min Read
Fewer Parts, Higher Efficiency

Simplify and add lightness: In the dual rack-and-pinion system, which is driven by a single polymeric worm gear, the motor travels up and down with the window as two intermeshed pinion gears traverse the one-piece molded rack. They system uses only half the number of parts required in conventional window regulator mechanisms.

A former Design News Excellence in Design winner is poised to be manufactured by DURA Automotive System Inc. (www.duraauto.com) as a new electric-powered window regulator that could help cut costs in the auto industry.

A dual rack-and-pinion system invented by Paul Fenelon, and named the Edmund Scientific Telescope winner in 1998 (DN 03.02.98, p.151), the design allows the motor to travel up and down with the window as two intermeshed pinion gears traverse a one-piece molded rack. The system, driven by a single polymeric worm gear, could eliminate unwanted horizontal side forces and the need for overpowered motors that are common in current window regulators, Fenelon says.

Using only 10 to 12 parts-half the number that is found in the predominant arm-and-sector and the drum-and-cable type regulator units-the system could also shed up to 3.3 lbs and 10 dB of noise per door, Fenelon adds. Fewer parts, hence less chance for failure and higher versatility, are exactly what caught the attention of DURA Automotive System.

"The simplicity is really the beauty of this product," says Greg Jager, director of sales at DURA, which has been testing and developing the regulator since 1997. For the past three years, the company has also been applying the regulator in retrofitting the doors on 10 different car models, and has found, to its surprise, another advantage of the system-the ease of installation.

"We are able to produce the product near the OEM plant location without having to go to low-cost manufacturing areas overseas," Jager says, pointing to the design's low labor content.

"From the automaker's point of view," he adds, "we believe it's cheaper and better."

The system also boasts greaseless and cleaner operation, Fenelon asserts, thanks to the self-lubricating, lightweight, high-strength polyamide material chosen by him from years of his research work in thermoplastics.

With reduced parts count, weight, energy, labor, and time, DURA projects 5% to 10% system savings for automakers. This savings include fewer warranty claims due to improved reliability.

About 48 million window regulators are manufactured in the U.S. each year. According to DURA, it is going to marketing the dual-rack-and-pinion design under the name of RackLift(TM) to Ford, Volkswagen, Daimler-Chrysler, Nissan, and their affiliates worldwide.

Declining to disclose further details, Jager says his company has received the first order for a 2005 four-door model that is manufactured at the annual volume of 150,000 to 200,000 vehicles.

Dual Rack & Pinion Racks Up Savings

Test Parameter

Dual Rail Drum Down

Dual Rail Drum Up

Dual Rack & Pinion Down

Dual Rack & Pinion Up

% Difference Down

% Difference Up

Stall Amps

24.3

22.3

17.9

20.0

-26.3

-10.0

Running Amps

11.9

13.2

2.1

5.2

-82.0

-61.0

Running Time (Secs)

3.0

3.7

1.9

2.3

-37.0

-38.0

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