White Pine news. [volume] (East Ely, Nev.) 1920-1923, 1923-07-15
DIFFERENTIAL| IS
NOT UNDERSTOOD
Purpose of Mechanism Is to De-
liver Equal Amount of Power
to Each Rear Wheel.

How many automobile owners know
what a differential is and of what use
1t is? A writer asserts that ever a
large proportion know little, if any
thing about it.
On all Co.'S with beyeled gear drive
such as is used on the modern passen-
ger cars, the differential is located in
the rear axle and its purpose is to de-
liver an equal amour Of power from
the engine to each of the rear drive
wheels, regardless of whether one is
going faster or slower than the other.
What DifferentiaI Does.
In driving a car in a circle. or any
part of a circle, the outer wheel has to
travel a longer distance than the one
on the inside, with the result that it
must turn around a greater number of
times. If the real axle were made of
one solid piece connecting the two
drive wheels, it would then be impos.
sible for one wheel to turn more rapid.
~ than the other, with the result that
one would have TO slip when rounding
n curve. Thus, the differential permits
one wheel TO turn faster Than the other,
therr'p keeping either of them from
~skidiing on the ground. At the same
time, it Is so constructed that 1t will
deliver the same amount of turning or
twisting torque on the wheel which is
turning the fastest as OF the other
one.
The construction of the d~ifferential
Is similar In principle to an ~"evener"
which Is placed back of a team OF
horses TO divide the load between the
two. The evener divides the load be-
tween the two so that, regardless of
whether one horse is ahead Of or to
the real of the other, he will be pulling
approximately his share of the load.
In the rear axle Of a car Is placed
the differential which divides the LOAF
from the engine. equally between the
two drive wheels, the same as the
evener divides the load between the
horses. The eQualizing action of the
differential car be seen by lacking up
the rear wheels Of the car, then put
ting the gear lever in low speed. Dis
engage the emergency brake and turn
one of the wheels forward or backward,
at the same time watching the effect
on the opposite wheel. You will no
tice that the other wheel turned df-
rectly opposite to the way in which
the one is going. This peculiar action
has led to many interesting stories
from new motorists when they have
discovered 1t.
Some Disadvantages.
While the differential Is a necessity
In the average car, 1t has some dlsad-
yantages which have not yet been
| satisfactorily overcome. In case one
wheel drops into a deep mudhofe 50 that
the tire cannot get traction, the differ
entail will allow this wheel 10 turn
around and prevents any more power
being delivered to the opposite wheel,
which might pull the car out were 1t
not for the differential action. Differ
ent mechanical devices have beer
shown at various times to lock two
rear wheels together under circnm-
stances of this kind. Due TO the COM
plex nature of these devices, however,
they have never come into commercial
use.
A great many patented types OF DIFF
f%erentials have been brought out at
different times to do away with this
summing of one wheel when In a slip
perry spot, but so far the standard type
Of bevel gear differential is used on
practically all standard makes of cars,
which seems to prove that nothing
better has beer brought out so far.