The New York herald. [volume] (New York, N.Y.) 1920-1924, 1920-12-19
MODERN GEARSET
IS NOT PERFECT
Engineers Agree 1t Is Most
Backward Unit in Pres
emit Day Car.
BY III. A. TARANToUs,
Member s. A. e.

In the ordinary course OF events, would
have taken years to bring out. Not
all these innovations have yet actually
made their appearances, bat the coming
national shows viii, undoubtedly place
most of them on public view.
Whatever else the war may bring us.
It Is devoutly to be hoped that Some
Improvement in present types Of trans
missions or gearsets may result Engi-
neers are unanimously agreed that the
gearset is far the most backward OF all
the mechanical units that go to make up
the modern motor car chassis. And we
may reasonably hope that some improve
ment in transmission design Is imminent
so that it win be OF interest to examine
the present types of this mechanical
unit in detail.
The function of the transmission or
gearset is to change the tractive effort
at the rear wheels in proportion to tho
effort needed. By Its means the rear
wheels are permitted to run slowly
while the engine is running fast, etc. In
general. this control over the tractive
effort is obtained by meshing gears Of
various sizes. In operation power is
generated by the engine, passes back
through the clutch. which delivers 1t to
shaft, which is part of the trans
mission unit. On this shaft are GER
tain number of gears which may be
shifted into and out Of engagement with
other gears. mounted on another shaft
known mechanically as a commensurate
These gears on the countershaft have
varying numbers of teeth, condition
which produces the changes in tractive
effort
The mechanical unit that we have
just described is known as the sliding
selective gearset, and while 1t serves itS
purpose fairly well 1t uses a tremendous
expenditure OF effort to accomplish what
is comparatively a small effect. We
need device which shall perform this
service in a simpler and easier way
without the constant danger of breakags
and injury that exists with the present
type.
Planetary Genrset.
While the sliding selective gearset is
the prominent type to-day. there are
other forms in use. The next most Inn
portant is the planetary searset used
in popular light car, which, in point
Of mere numbers, makes the type i'm
portaut The planetary gearset consists
Ok a group OF spur gears, always in
mesh with central or master gear
This master gear is known as the sun
gear and the spur gears as planetary
gears. from a resemblance OF the set to
The operations OF the solar system. In
voive on each other. this action being
induced by stopping the movement OF
the parts supporting the gears, which Is
accomplished by means OF a sort of
brake, When the gearset is in high It
revolves as unit. giving remarkably
efficient action. One of the drawbacks
to the planetary gearset is the fact
that it can only be constructed for two
speeds. the adding OF other speeds
necrs are leath to employ the type.
In the truck field we find third type
OF gearset, known as the constant mesh
type. This variety of transmission has
not come into the passenger car field as
yet and SO Is OF no interest to us for
the present consideration.
II Is rather remarkable fact that the
simplest and theoretically the most ef-
ficient type OF gearset, the friction set
has passed out Of use in the automobile
ffold. The friction gearset consists Of
two discs---one driving, the other driven.
In operation me driven disc is brought
into conta { with the driving disc, the
rate of speed being determined by it's
distance from the centre Of the driving
member. Obviously this arrangement
gave an almost unlimited number Of
speeds, smoothness OF action but the
great trouble was that the sets did not
work. At one time 1t enjoyed great pop
ularity. but it gradually was abandoned
for heavy work, and finally even the
lightest ears gave IL up In favor Of the
sliding selective type. It Is regrettable
that the friction set could not stand UP
under the needs OF service, for IL had
all the theoretical virtues that delight
the heart of the engineer.
Much Care Needed.
II the car owner will stop for Just one
moment and consider the essential con-
struction Of the conventional gearset he
will realize the need for great caro- in
operation and maintenance. Two shafts
holding sets of gears which must be
brought into engagement while the parts
are spinning at high rate of speed
point to ever present danger of break
age and injury. And this Is actually so.
Brcakage OF members in the gearset and
bending OF the shafts so that they are
out of alignment are common in searset
operation. When the shafts once go out
of line there is no hope of decent opcr-
alton until the condition Is remedied:
the gears will clash and growl. the teeth
win chip or suffer more serious breaks
and replacement of gears will do no
earthly good until the entire transmits
sion is properly lined UP again. When
the shafts are out of line the gears do
not engage evenly. as they are intended
TO do. which is the whole secret of the
trouble.
The first thing to do TO keep the gear
set UP to proper operation pitch Is to
give it proper fabrication. OIL is the
proper lubricant for this unit, not grease.
In winter IL will be well to use a some
what thinner oil than In hot wea Their,
as the cold tends to thiclen the OIL
anyway. Every two or three months, or.
better, every thousand miles of run
ming, the oil should be drained of from
the gearset housing. which should be
flushed with kerosene and then refiiled
witch fresh oil. Neglect of this precau-
ton will probably bring premature fall
ure OF the unit.
Finally let us call attention to the
fact that without a gearsct operating
efficiently the entire operation of the
car Is thrown out of gear. Under
standing that the car owner should give
the part the most scrupulous care that
he is capable OF supplying. syste-
matte care will keep this~unit moving
efficiently for a long time and this
care is easier to give than the time and
trouble necessary TO repair damage to
the part. not to mention the probable
repair bills.
1901 ATrnO mr. rrr-c crrarr--