Quote:
Originally Posted by petefoss
There are some very serious technical hurdles with wheel motors. The biggest being "unsprung weight". Very heavy wheels including tires, rims, brakes and a wheel motor put huge forces on the suspension. Especially pot hole loads where the suspension sees loads 3 to 5 times the static loads.
Back at GM R&D and Powertrain we talked about it a lot and the consensus was IF we did 4 motors they would be mounted on the vehicle frame with drive shafts out to the wheel to decrease the unsprung weight. Wheel motors is one of those concepts that works great on paper or in a concept show car but falls flat when you try to actually engineer a robust solution.
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Yes, and it’s not only the weight (unsprung mass) of the electric motor at each wheel, but the newest electric cars use small and light-weight motors that spin at very high RPM, so if mounted directly at wheel, it would also involve the added weight/mass of the speed-reducing transmission, or else it would require a much heavier low-speed motor.
I’ve seen pictures of the upcoming electric F-150 showing an independent rear suspension that looks very similar to that of the Ford Expedition’s. My guess is that an electric Transit will likely also include an IRS for both RWD and AWD models, assuming they are not all built as AWD. I certainly hope Ford doesn’t keep the Transit’s live rear axle.
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