Service Manual

OPEN
CENTER
CLOSED
CENTER
3.4297.41
HYDRAULIC
PRESSURE
Spool Valve A spool valve is a directional
valve used to control oil flow. There are
two
types of spool valves: open center and closed
center. Both types allow oil flow to be diverted to
a remote circuit when the spool is not centered.
A closed center spool valve stops flow from the
pump when it is centered. This type of valve is
not used with a positive displacement pump.
An open center spool valve allows oil from the
pump to pass through the valve when the spool
is centered.
Actuator
A hydraulic actuator is a device which converts
hydraulic pressure and flow into mechanical
energy. The
two most common types of
actuators are hydrostatic motors and hydraulic
cylinders.
Actuators By Type
A Motor is simply a pump used backwards. It
takes hydraulic pressure and flow from a pump
and converts it back into rotary mechanical
energy.
Due to their similarities in function, many motors
use designs similar to pumps. In some cases,
the exact same configuration can be used as a
pump or motor.
Productivity Series
14