Fresh Heavy Duty Truck Safety Tech Emerges at CES 2025
Magnetic steering feedback “brake,” planetary ball-ramp rear steering, electric recirculating-ball front steering, and 5 million electric rear brakes.
Software-defined vehicles were everywhere at CES 2025, and they weren’t all cars and e-VTOL air taxis. The heavy-duty segment was also well represented, with suppliers Schaeffler and ZF showing off some noteworthy tech aimed at heavy duty trucks.
Magnetic Steering “Brake”
Steer-by-wire always requires two motors—a big honker down on the chassis that moves the wheels, and a smaller one up in the cabin that makes the steering wheel feel like it’s connected to the wheels, hopefully delivering little twitches as the grip levels change, and coming to a hard stop at the end of the front-wheel’s steering travel. Sizing a motor large enough to provide that end-stop can result in larger, heavier, pricier force-feedback motors, so Schaeffler dreamed up a magnetorheological (MR) “brake” powerful enough to stop the wheel with full voltage applied, providing variable feedback at lower voltages for the desired feedback.
This application is novel in automotive, but it is widely used to give joysticks feedback in industrial applications. Schaeffler claims that adding its magnetic brake allows use of a motor one-quarter the size but cautions that the stiction it introduces can only be felt when the wheel is moving—so your sportscar helm might not feel naturally “loaded up” during your steady-state drive through the Nürburgring’s carousel.
Schaeffler Planetary Roller-Screw Rear Steering Gear
This gear drive was a new one on us. A normal planetary gear set in an automatic transmission or a Prius e-CVT consists of an outer ring gear and an inner sun gear connected by several planet gears in a carrier. It provides a ratio change in rotational speed depending on which element is held and which is driven. Well here, instead of straight or helical-cut gears enmeshed, the gear teeth are a spiral-cut like in a screw. The ring gear is the housing, and an electric motor spins the planet carrier as the planet screws drive the (non-rotating) sun-gear screw left or right to steer the wheels. The screw threads provide much greater contact area than a similar ball-screw actuator could (and WAY more engagement than a simple pinion moving a rack), so the forces it can control are greater—sufficient to steer dual rear wheels or a heavily loaded axle.
ZF Heavy Duty Solutions
At CES 2025, ZF announced it has signed a contract to provide five million dry-corner rear brake-by-wire systems for class 2–5 trucks (think Ford F-250 to F-550 sized trucks, but the OEM may or may not be Ford). This disc system handles service and parking brake functions, using one or more ball-ramp-type actuators per wheel to compress the pads. ZF reports strong demand for dry rear brake-by-wire, to simplify production (no bleeding!), and because it’s well suited to the braking needs of medium to heavy-duty trucks. (The cost of going all-in on brake-by-wire in the front as well is still considered prohibitive.)
ZF also has a contract to supply the recirculating-ball type electric power steering we covered last April, and also announced that it will soon enter production of a hybridized version of its ubiquitous "8HP" automatic transmission at its Gray Court, SC facility. Soon our heavy-duty tow rigs and work trucks may enjoy most of the same ADAS features our cars do.
I started critiquing cars at age 5 by bumming rides home from church in other parishioners’ new cars. At 16 I started running parts for an Oldsmobile dealership and got hooked on the car biz. Engineering seemed the best way to make a living in it, so with two mechanical engineering degrees I joined Chrysler to work on the Neon, LH cars, and 2nd-gen minivans. Then a friend mentioned an opening for a technical editor at another car magazine, and I did the car-biz equivalent of running off to join the circus. I loved that job too until the phone rang again with what turned out to be an even better opportunity with Motor Trend. It’s nearly impossible to imagine an even better job, but I still answer the phone…
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