basic hydraulic
TRANSCRIPT
1
Basic Hydraulic
Pumps
Axial Piston Pump
Gear Pump
Motors
Check Valve
Reservoirs
Conditioners
Pascal’s Law
Application Principles
Hydraulic Valve JIC
Build With JIC’s
Hydraulic Cylinder Principles
Cylinder Leakage Test
Relief Valve
Lines and Connections
Pressure Differential Relief
Hydraulic Fluid
Least Resistance
Open vs ClosedJIC
3
Liquids Have no Shape of their own
4
Liquids are Practically Incompressible
5
Liquids under pressure follow what path?
Path of least Resistance
6
Path of Least Resistance
10 lbs
Pascal’s LawPascal’s Law
Pressure Exerted on a Confined Fluid is Transmitted Undiminished in All Directions and Acts With Equal Force on Equal Areas and at Right Angles to Them.
7
Imperial
Metric
Application PrinciplesApplication Principles1 lb (.45kg)Force
1 sq in (.65cm2)Piston Area
1 psi
(6.9kpa)
10 sq in (6.5cm2)Piston Area
10 lbs (4.5kg)
11
Pump TypesPump Types
Positive Displacement -With each revolution a specific
amount is pumped somewhere– Low Volume, High Pressure
Non Positive (IE: Water Pump)– High Volume, Low Pressure
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14
JIC SymbolsJIC Symbols
Joint Industry Council
Symbolic Drawings used in Schematics to Represent Components.
Pumps (JIC Symbols)Pumps (JIC Symbols)
Arrow Showing Oil FlowOUT
Constant Displacement Single Direction
Bi-Directional, Variable Displacement
16Pumps convert mechanical power into hydraulic force
Axial Piston PumpAxial Piston Pump Neutral Position
Vertical Swashplate
Rotating GroupTypically 9 Pistons
Piston
Swash Plate
18
Piston
Piston
Engine Shaft Pumps
Pressure Oil Each Piston
Axial Piston PumpAxial Piston Pump
Forward PositionAngled Swashplate
Rotating GroupTypically 9 Pistons
20
Pressure
Charge Oil
Axial Piston PumpAxial Piston Pump
Reverse PositionAngled Swashplate
Rotating GroupTypically 9 Pistons
21
Charge
Pressure
In Out
Gear Pumpor MotorGear Pumpor Motor
23
Motors (JIC Symbols)Motors (JIC Symbols)
Single Direction
Arrow Showing Oil Flow IN
Bi-Directional
25Motors converts hydraulic force into mechanical power
ReservoirsReservoirs
1. Vented 2. Pressurized
3. Return Above Fluid Level
4. Return Below Fluid Level
26
Lines and ConnectionsLines and Connections
27
Working Line (Main)
Pilot Control Line
Drain Line
Flow Direction
Crossing Lines
or
Connecting Lines
Flexible Line
Check ValveCheck Valve
28
Checked Flow Free Flow
Pilot Operated
Spring Assisted
29
Relief Valves
Protects the Pump and Lines from excessive pressure
Returns fluid back to the reservoir
Relief ValveRelief Valve
30
Supply
Pilot supply
Return toReservoir
Pressure Differential ValvePressure Differential Valve
31
Supply
Senses the DIFFERENCE in Pressure
Manual On/Off ValveManual On/Off Valve
32
Fluid ConditionersFluid Conditioners
Filter
Oil Cooler 33
3434
FiltersFilters
Micron 1 Millionth
of a Meter or1 Thousandthof a Millimeter
Internal FilterBypass Valve(Optional)
35
Types of Hydraulic Systems
Open Center
Closed Center
The control valve that regulates the flow from the pump determines if system is open or closed.
Do not confuse Hydraulics with the “Closed Loop” of the Power Train. (Hydro)
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Hydraulic Valve JICHydraulic Valve JIC
Trapped Oil
Closed Center HydraulicsOpen CenterFlow in Neutral
Extend 38
Hydraulic Valve JICHydraulic Valve JIC
Retract 39
Hydraulic Valve JICHydraulic Valve JIC
Neutral Again 40
Hydraulic Valve JICHydraulic Valve JIC
42
Lift CylinderLift Cylinder
Extend
44
Lift CylinderLift Cylinder
Leak Down Where Does
the Oil Go??
46
Lift CylinderLift Cylinder Is it Possible for
This Rod to Retract Even Withthe Piston Removed??
47
Cylinder Hose FailuresCylinder Hose Failures Effects On Line
Pressure When a Cylinder Piston Packing isLeaking
3” Diameter Piston1.5 x 1.5 x 3.1416 = 7.07 sq.in.Results in 2122 PSI
1.5” Diameter Rod.75 x .75 x 3.1416 = 1.77 sq.in.Results in 8475 PSI
15000 lbs of Down Force
Retract 49
Hydraulic CylinderLeakage TestHydraulic CylinderLeakage Test
Depending on theSystem, You May
Have to Cap This LineTo Prevent Return
Oil From Leaking Out
5050
JIC SymbolsJIC Symbols
PM Would This Hydraulic Drive System Work?
Hydraulic Drive Does NOT Provide Dynamic Braking
Common Reservoir
Common Reservoir
Build the System
Yes, In one direction
5151
JIC SymbolsJIC Symbols
PM
Closed Loop Hydrostatic Transmission
Hill Simulation
5252
JIC SymbolsJIC Symbols
PM
Closed Loop Hydrostatic Transmission
Hill Simulation
5353
JIC SymbolsJIC Symbols
PM
Oil Cooler
Build the System
Common Reservoir
Common Reservoir
Oil Filter
InletCheck
InletCheck
5555
JIC SymbolsJIC Symbols
Build the System
PM
Oil Cooler
Oil Filter
Charge ReliefValve
Oil CoolerBypassValve
Filter BypassValve
5757
JIC SymbolsJIC Symbols
Hydrostatic Transmission Components
Oil Cooler
Oil Filter
PM
Charge ReliefValve
Oil CoolerBypassValve
Filter BypassValve