Hydraulic Power

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Hydraulic Power

• basics

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Pascals Law
Pressure exerted at any point on a confined
liquid is transmitted undiminished in all
directions.
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Hydraulic Terms
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Hydraulic
Tool or equipment powered by the movement of
fluid under pressure. Examples are brakes, jacks
tractor lifts.
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Pneumatic
Tool or equipment powered or supported by the
movement of compressed air.
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PSI
Pounds per Square Inch determines amount of force
GPM
Gallons per Minute determines speed of action
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Basic principle
Pressure applied to piston A is transferred
equally to a piston of the same size B because
PSI is the same throughout the system.
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hydraulic advantage
If the surface area of piston B is 10 times the
surface area of piston A, then the force
applied to piston A is multiplied 10 times as
the force exerted on piston B. PSI is equal
throughout the system.
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Input / Output
Force input on a hydraulic system or component
results in transfer of power to output of force
by the system or component.
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Pump
Functions in a hydraulic system by pressurizing
and moving fluid from one part of the system to
another.
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Hydraulic pumps are usually one of four
typesPISTONGEARVANEINTERNAL ROTOR
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Piston Pumps

• Work well at PSIs of 2000 or more
• Single piston pump used in bottle jacks
• Require several pistons working together to
  generate enough volume for tractor applications
• Necessarily involve many moving parts

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Gear Pumps

• Work well at 1500 PSI and below
• Work with a minimum of moving parts
• Less expensive to manufacture than piston type
  pumps

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Gear Pump
driven gear
idler gear
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Hydraulic Motor
Receives power from moving fluid to transfer
hydraulic power to mechanical rotating force.
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Cylinder
Piece of equipment that transfers hydraulic power
into mechanical movement in one or two directions
only.
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Hydraulic Cylinder
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Single-acting
Refers to a hydraulic cylinder that works in one
direction only.
Double-acting
Refers to a hydraulic cylinder that pushes and
pulls.
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Single-acting cylinder
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Double-acting Cylinder
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Piston
Internal component of a hydraulic cylinder that
is moved in a linear motion by the action of
fluid introduced into the cylinder.
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Shaft
The polished round bar that is extended from and
retracted into a hydraulic cylinder.
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Stroke
The length of movement that a hydraulic cylinder
is capable of producing.
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Seal
Found in hydraulic components function is to
keep fluid from leaking between moving and
non-moving parts
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Check Valve
Restricts flow of fluid to only one direction
allows pressure to build up or be maintained.
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Spool Valve
Controls direction of flow of fluid in a
hydraulic system to cause the different parts of
the system to function.
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The first hydraulic power lift for a tractor was
introduced in 1935 by John Deere. This unit only
had two positions, up and down, but the hydraulic
action cushioned the lowering of the implement.
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Rockshaft
Rotating shaft on a modern tractor powered by an
internal hydraulic cylinder used to transfer
power to the implement lift.