The replaceable element of a fluid filter, The pumping unit
from a vane pump, composed rotor, ring, vanes and one or both side
Valve: A valve that is inserted into a standard size cavity
in a manifold block and is held in place with either self contained
screw threads or a cover secured with bolts. May be slip in or screw
in types. Perform directional, pressure or flow control functions.
A localised gaseous condition within a liquid stream which occurs
where the pressure is reduced to the vapor pressure.
A compartment within a hydraulic unit. May contain elements
to aid in operation or control of a unit.
To replenish a hydraulic system above atmospheric pressure.
To fill an accumulator with fluid under pressure.
Pressure: The pressure at which replenishing fluid is forced
into hydraulic system.
Valve: A valve which permits flow of fluid in one direction
A restriction, the length of which is large with respect to its
cross section dimension.
An arrangement of components interconnected to perform a specific
function within system.
Center Valve: One in which all ports are blocked in the center
or neutral positions.
Center Circuit: One
in which flow through the system is blocked in neutral and pressure
at the pump outlet is maintained at the maximum pressure control
The switching sequence of drive voltage into motor phase windings
necessary to assure continuos motor rotation. A brushed motor relies
upon brush/bar contact to mechanically switch the windings. A brushless
motor requires a device that senses rotor rotational position feds
that information to a drive that determines the next switching sequence.
Loop: A broadly applied term relating to any system where the
output is measured and compared to the input. The output is then
adjusted to reach the desired condition. In motion control, the
term describes a system wherein a velocity or position (or both)
transducers is used to generate correction signals by comparison
to desired parameters.
Signal: An external signal variable pumps and motors which alters
displacements when system pressure exceeds its adjusted pressure
A single hydraulic or electric unit.
The change in volume of a unit volume of fluid when subjected
to a unit change in pressure.
A heat exchanger used to remove heat from the hydraulic fluid.
valve: A pressure control valve which maintains backpressure
to prevent a load from falling.
Damping: A system is critically damped when the response to
a step change in desired velocity or position is achieved in the
minimum possible time with little or no overshoot.
Frequency: The frequency at which the gain intercepts the 0db
point on a Bode plot (used in reference to the open-loop gain plot).
A device sometimes built into the ends of a hydraulic cylinder
which restricts the flow of fluid at the outlet port, thereby arresting
the motion of the piston rod.
A device which converts fluid power into linear mechanical force
and motion. It usually consists of a movable element such as a piston
rod, plunger rod, plunger or ram, operating within a cylindrical