DECKMASTER
Thrust plate
COMMERCIAL'S original "pressure-pocketed" thrust
plates are another built-in feature of Model 15H pumps
and motors and serve a most important function. By
"pressure-pocketing", a dynamic seal is created which
prevents oil under high pressure from flowing toward the
low pressure side of the thrust plate. Therefore, a
positive seal is created which contributes to volumetric
efficiency of pumps in excess of 90%. These floating
type thrust plates exert a force at all times against the
small sealing area at the gear faces. The small loss of
mechanical efficiency due to friction between thrust
plates and gear faces results in considerable gain in this
volumetric efficiency.
Bearings
Bearings are built into COMMERCIAL Model 15H
pumps and motors to maintain positive shaft and gear
alignment. Anti-friction bearings are designed to absorb
all radial and thrust loads always present to the
unbalanced loading conditions inherent in gear type and
motors. Two heavy duty, anti-friction inboard gear
journal.
ings
are
provided
for
each
gear.
COMMERCIAL also provides a ruls6¢d outboard
bearing, a ball bearing type, for all pumps and motors.
Bearings are fit to the gear hubs, not to the drive shaft.
Because gear hub is integral with the gear, larger
bearings, necessary for satisfactory operation at 2000
psi, are possible. Such gear hub construction
permits more accurate machining held to closer
tolerance.
Gears
For high volumetric efficiency of gear type pumps and
motors, complete sealing between all gear tooth contact
surfaces must be maintained. As operating pressures
increase, this contact becomes more difficult to
maintain. COMMERCIAL found that gears which were
obtainable on the open market did not have tooth
surfaces smooth and sufficiently accurate for high
efficiency operation at 1500 psi and higher. Gear
surfaces are precision finished, each pair. matched
perfectly. COMMERCIAL manufactures gears for all
their pumps and motors and makes every effort in
design and manufacture to assure producing gears
which will give the quietest and most efficient operation.
