On Sat, 17 Feb 2018 18:07:34 +0000, Tim+ wrote:

Vir Campestris wrote:
On 17/02/2018 06:38, Johnny B Good wrote:
A fully developed active energy recovery suspension system could
ultimately overcome this problem of 'unsprung mass'. It's also worth
remembering that the suspension components themselves (spring, damper
and drive shaft on each driven wheel) form a part of this 'unsprung
mass'. Also, let's not forget the mass of the disk brake assemblies
which, with regenerative braking, can be reduced in size thus offering
yet a further reduction in 'unsprung mass'.

If you're going to put a drive shaft for each wheel connected to an
electric motor why not put the disc inboard next to it? That would
really cut the unsprung weight (to just half the shaft)

Andy


One problem with that is that it moves the disc (and pads) out of reach
of easy inspection/service.

The real problem with that is the possibility of a high speed wheel
lockup under emergency braking snapping the drive shaft as a result of
the rotational energy stored in the wheel. You want to decouple the mass
of the brake assembly from the unsprung mass but not at the risk of
completely disconnecting it from the wheel in an emergency braking
situation.

--
Johnny B Good