Turning To Drive-By-Wire

Drive-by-wire is causing the jitters at screw machine shops. Two concept cars from European sources have been demonstrated at recent European motor shows.

Drive-by-wire is causing the jitters at screw machine shops. Two concept cars from European sources have been demonstrated at recent European motor shows. The Novanta executive saloon and Filo town car are produced jointly in Italy by Bertone of Grugliasco and SKF's Automotive Division in Airasca.

If your clients are in the automotive business, think about what you are machining now but may not be in 10 years. Picture this: You sit in the Novanta and are shocked to see no steering wheel, pedals, gear stick or parking brake lever. Tucked away in the driver's door is a compact-looking pendant, which you move to a position in front of you. Your car already knows—via your mobile phone—who you are, if you are cleared to drive the car and how you like the road "feel" when steering. U2 is already into its first number.

This demonstrates the effects that a futuristic system will have on the screw machine shop. In the Novanta, smart electronically controlled feedback servomotor driven actuators operate the brake-by-wire disc brake callipers; operate the steering mechanism; change gears; and apply the handbrake. You just press the requisite buttons.

There are no hydraulics, hydraulic pump, valves, hydraulic line connectors or hydraulic cylinders, and the pedal box assemblies are gone. In their place are the actuators, basically a simple servomotor assembly driving a ballscrew to provide linear motion. In the place of the hydraulic components, there are electric motor bodies and rotor spindles with, presumably, press-fit ball bearing assemblies. These drive a yet-to-be produced high volume ballscrew assembly. It is a precision ballscrew similar in concept to what is used in machine tools. There may be five in a braking system, four for road brakes and one for the parking brake.

On steering-by-wire, the rack and steering column are no more—a great deal of high volume, precision turning, milling, boring, drilling, tapping and grinding are no longer needed. In their place are two actuators driving ballscrews to operate the steering linkage. Steering is done by something akin to an aircraft pilot's console. It uses some mechanical linkages and pins, and two geared quadrants. The latter could probably be fine-blanked. It brings the manufacturing operation down to the machining of, probably, die-cast motor housings and the fitting of bearings and the ballscrew assemblies.

Take a look at the gearboxes on these concept cars. Two servodriven ballscrew actuators open and close the clutch and perform the gearshift. Then the final "death knell" to having those pedals is throttle-by-wire. Gone are the pins, shafts and bearings and the machining of pedal boxes.

I'm not sure if anyone knows what drive-by-wire will mean to the production machine shop. Ballscrew assemblies are still a batch-produced item for the machine tool, assembly machine and handling and packaging industries. Mass-producing millions of ballscrew nuts will not be easy. A cold-rolling technique could be applied.

It is not just drive-by-wire that looks like it will be overturning future machine tool requirements. There are already a few cars running around with electronically controlled engine valves. These cars do not need camshafts. In their place are solenoid-actuated valves operated by a computer program.

Of prime concern is when all these changes will take place. Electronic engine valves should be "standard" by 2010, when instead of "gas," synthetic and "sun" fuels will be burnt. As for the drive-by-wire systems, the gear shift-by-wire, throttle-by-wire and parking brake-by-wire are happening now and will become more widely used in the next 5 years, because they can operate off the standard 12V system. Brake-by-wire and steer-by-wire need 42V systems, and it will be several years before any standard is agreed upon.

As the Boy Scout motto says, "be prepared." The automotive components industry is going to change eventually.