The Monmouth inquirer., 1923-04-12
D%IFFERENTIAL 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 even a
large proportion know little. If any
thing about 1t.
On all cars with beveled gear drive
such as is used on the modern passen-
ger cars, the differential Is located in
the real axle and its purpose is to de-
liver an equal amount 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 Ditferential 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 1t
must turn around a greater number of
times. If the rear axle were made of
n solid piece connecting the two
drive wheels, it would then be impos.
sible for one wheel to turn more rapid.
ly than the other, with the result that
one would have to slip when rounding
q curve. Thus, the differential permits
one wheel to turn faster than the other,
thereby keeping either of them from
skidding 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 on the other
one.
The construction Of the differential
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 n horse is ahead of or to
the rear 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 load
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
d%ifferential can 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 d.
rectIy 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 it.
Some Disadvantages.
While the differential is a necessity
In the average car, it has som disad-
vantages which have not yet been
satisfactorily overcome. In case n
wheel drops into a deep mudhole SO that
the tire cannot get traction, the differ
entail will allow this wheel to turn
around and prevents any more power
being delivered to the opposite wheel,
which might pull the car out were 1t
not for the d%ifferential action. Differ
ent mechanical devices have been
shown at various times to lock two
rear wheels together under circum-
stances of this kind. Due to the com
pick nature of these devices, however,
they have never come into commercial
use.
A great many patented types of diff
~ferentiaIs have been brought out at
different times to do away with this
spinning Of one wheel when In a slip
perry spot, but so far the standard type
of bevel gear dlfferential is used on
practically all standard makes of cars,
which seems to prove that nothing
better has been brought out SC far.