Re: torsen tech 201

[Orin Eman <orin@wolfenet.com>]

> however (and orin makes the same mistake), when the torsen is at the bias
> ratio, *no* further torque biasing occurs.

This is ambiguous.  Who is saying what?
What do you mean by further torque biasing?
At the bias ratio, by definition, the output torques
are proportioned according to the bias ratio.
I never said anything different.  If the torques
are proportioned differently, then you aren't at the
bias ratio.

the diff locks at the bias ratio,
> and *holds* the bias ratio, operating as an open diff.  it can't shift
> torque anywhere other than where ever dictated by tractive force.

It can't see tractive force directly.  All it can see is
relative shaft speed and the torque reactions of the shafts.
Torque reaction as seen by the torsen for a shaft is tractive force _plus_
(moment of inertial of an output shaft * angular acceleration
of that shaft).  I merely applied this pesky acceleration term
which had in the past been ignored.

 as long
> as the output shafts are spinning enough relatively, *all* torque is
> distributed according to the bias ratio.

And that was a very small relative rotation.  Work out 0.5 rad/sec in RPM.

> as should be obvious, it is only when the relative output shaft speeds of
> the unit fall back into the "low speed" range, that the torsen "locks"
> again.

What I was considering was the case where a shaft is turning slower
due to cornering with the diff in your 'unlocked' state, ie receiving
75% of the torque.  Now what happens if that shaft loses grip
at its wheels?  That pesky acceleration term.  Frictional forces
oppose motion, therefore the frictional forces inside the torsen
continue to oppose the relative rotation of the slower shaft.
Any torque directed to the slower shaft in excess of its
tractive ability accelerates that shaft and whatever it is
attached to (classic spin up of an axle just like an open diff).
As you say:  "it is only when the relative output shaft speeds of
the unit fall back into the "low speed" range, that the torsen "locks"
again."  So still 75% to the slower moving shaft until it accelerates
up to within 0.5 rad/sec (your figure) of the faster moving shaft.

All I have really said is that the _inertia_ of the output shafts
and all they are connected to must be taken into consideration. 

Orin.