Delphi Corp.'s future growth in electronic steering systems turns on plastic.
As the auto supplier ramps up for the launch of its first North American E-Steer power steering program, it is replacing the hoses and pumps of a conventional hydraulic system with finely machined plastic gears.
``It's a lead-in technology to other programs,'' said Steve Bradley, manager of manufacturing engineering for Troy, Mich.-based Delphi's electronic steering group.
Delphi has produced the plastic worm gear set for electronic steering for about two years in Europe, supplying Volkswagen AG Lupo and Fiat Auto SpA Punto from Cadiz, Spain.
Now it is spending $315 million to revamp its Saginaw Steering Systems plant in Saginaw, Mich., to begin the program for an unspecified General Motors Corp. vehicle. The company will produce as many as 400,000 units annually and employ 200 people by next year.
Electronic steering is part of the auto industry's change from traditional control systems for brakes and steering to a ``by wire'' system of electronic controls.
Hydraulic systems pull energy from the engine through a drivebelt and pulley, siphoning off power while requiring the use of oil and environmentally hazardous fluids, Bradley said. An electronic system operates independently, improving fuel economy, and can be fine-tuned to meet the specific demands of each car - and even each driver.
European users already can flip a switch between city and highway driving, allowing a different response from the vehicle whether it is zipping down the open road or angling for a tight parking space.
Those gears within the system, though, placed new demands on Delphi engineers to avoid the noise and chatter of a metal gear system, said David King, senior manufacturing engineer in the division's innovations center and a co-inventor of the plastic gear unit.
The gears are directly behind the car's dashboard, meaning there is little to stop unwanted noise from filtering into the passenger compartment.
``That's what drove us to the plastic worm gear,'' he said.
The system itself includes two gears set at 90-degree angle, powered by an electric motor from the steering column. Delphi is not releasing any information on the proprietary resin blend used in the application.
The company has adapted equipment used to machine metal gears to produce the same engineered pattern from a preformed block of the resin. Delphi considered injection molding, King said, but was not convinced that existing tools could replicate the accuracy it needed.