1. Hydraulic Foundations GOLF TURF John Deere Training Department &
Hydraulic
GOLF
TURF
Training Department
&
John Deere
Foundations
Hydraulic Fundamentals

2. Hyd Fundamentals Slide Index
Hyd Fundamentals Slide Index
(Left Click Selection Box)
Hydraulic Fluid
Check Valve
Least Resistance
Relief Valve
Pascal’s Law
Pressure Differential Relief
Application Principles
Conditioners
JIC
Open vs Closed
Pumps
Hydraulic Valve JIC
Axial Piston Pump
Hydraulic Cylinder Principles
Gear Pump
Cylinder Leakage Test
Motors
Build With JIC’s
Reservoirs
Lines and Connections
Hydraulic Fundamentals

3. Liquids Have no Shape of their own

4. Practically Incompressible
Liquids are
Practically Incompressible

5. Liquids under pressure follow
what path?
Path of least Resistance

6. Path of Least Resistance
Path of Least Resistance
10 lbs
Hydraulic Fundamentals

7.
Imperial
Pascal’s Law
Metric
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.
--Hydraulics is a means of power transmission
--Oil is the most commonly used medium because it serves as a lubricant and is practically non-compressible (it will compress approximately 1/2 of a 1 percent per 1000 PSI).
--Weight of oil varies with viscosity, but averages between 55 to 55 lbs per cubic foot. (at 100 degrees F).
NOTE: A cubic foot of oil is 1728 Cu.In (12x12x12). A gallon is 231 Cu.In., so a Cubic Foot of oil is equivalent to 7.48 Gallons.
--A liquid is pushed, NOT DRAWN, into a pump. Atmospheric pressure equals 14.7 PSI at sea level.
--Oil takes the course (path) of least resistance.
FORMULAS;
1. H.P. = GPM x Pressure x or- H.P. = GPM x PSI / 1714
2. One H.P. = ft./lbs. per minute (33000 lbs raised 1 ft in 1 minute)
One H.P. = 746 Watts, One H.P. = 42.4 BTU per minute
3. Required Area of a transmission line;
Area = GPM x / velocity (ft./sec) -or- Velocity (ft./sec) = GPM / x Area
Pascal’s Law, named after Blaise Pascal (French ) 7
Hydraulic Fundamentals

8. This slide illustrates one of the basic principles of hydraulics;
This slide illustrates one of the basic principles of hydraulics;
LIQUIDS TRANSMIT APPLIED PRESSURE EQUALLY IN ALL
DIRECTIONS.
BUILDS:
1. When a 1 lb (.45kg) force is applied to this handle and the area of the
piston is 1sq in (.65cm2), with the confined fluid, what PSI (kpa)
pressure will be produced? (1psi (6.9kpa))
Note that this pressure is exerted in every direction.
2. With a 10 sq in (6.5cm2) piston, how much weight will this system
lift? This principle is what allows us to multiple our work efforts.
With 1 lb (.45kg) of down pressure, we are able to lift 10 lbs (4.5kg).
Pressure is caused by a resistance to flow, in this case the 10 lb
(4.5kg) weight. Point out that resistance to flow is what causes
pressure. In this example, if there were a 100 lb (45kg) weight on the
right side (in place of the 10 lb (4.5kg) weight), how much pressure
would be required to lift it. (10 PSI (69kpa)).
Hydraulic Fundamentals

9. Pascal’s Law, named after Blaise Pascal (French 1623-1662)
IMPERIAL
--Hydraulics is a means of power transmission
--Oil is the most commonly used medium because it serves as a lubricant and is practically non-compressible (it will compress approximately 1/2 of a 1 percent per 1000 PSI).
--Weight of oil varies with viscosity, but averages between 55 to 55 lbs per cubic foot. (at 100 degrees F).
NOTE: A cubic foot of oil is 1728 Cu.In (12x12x12). A gallon is 231 Cu.In., so a Cubic Foot of oil is equivalent to 7.48 Gallons.
--A liquid is pushed, NOT DRAWN, into a pump. Atmospheric pressure equals 14.7 PSI at sea level.
--Oil takes the course (path) of least resistance.
FORMULAS;
1. H.P. = GPM x Pressure x or- H.P. = GPM x PSI / 1714
2. One H.P. = ft./lbs. per minute (33000 lbs raised 1 ft in 1 minute)
One H.P. = 746 Watts, One H.P. = 42.4 BTU per minute
3. Required Area of a transmission line;
Area = GPM x / velocity (ft./sec) -or- Velocity (ft./sec) = GPM / x Area
Pascal’s Law, named after Blaise Pascal (French )
Hydraulic Fundamentals

10. Pascal’s Law, named after Blaise Pascal (French 1623-1662)
METRIC
--Hydraulics is a means of transmitting power.
--Oil is the most commonly used medium because it serves as a lubricant
and is practically non-compressible (it will compress approximately 1/2
of 1 percent per 690 kpa).
--Weight of oil varies with viscosity, but averages between 23 to 25 kg
per cubic foot. (at 100 degrees F).
NOTE: A cubic foot of oil is 1728 Cu.In (12x12x12). A gallon is 231
Cu.In., so a Cubic Foot of oil is equivalent to 7.48 Gallons.
--Liquid is pushed (by Atmospheric Pressure), NOT DRAWN, into a
pump. Atmospheric pressure equals 14.7 PSI at sea level.
--Oil takes the path (line) of least resistance.
FORMULAS;
1. H.P. = GPM x Pressure x or- H.P. = GPM x PSI / 1714
2. One H.P. = ft./lbs. per minute (33000 lbs raised 1 ft in 1 minute)
One H.P. = 746 Watts, One H.P. = 42.4 BTU per minute
3. Required Area of a transmission line;
Area = GPM x / velocity (ft./sec) -or- Velocity (ft./sec) = GPM / x Area
Pascal’s Law, named after Blaise Pascal (French )
Hydraulic Fundamentals

11. Application Principles
Application Principles
1 lb (.45kg) Force
1 sq in (.65cm2) Piston Area
10 lbs (4.5kg)
10 sq in (6.5cm2) Piston Area
This slide illustrates one of the basic principles of hydraulics;
LIQUIDS TRANSMIT APPLIED PRESSURE EQUALLY IN ALL DIRECTIONS.
BUILDS:
1. When a one pound force is applied to this handle and the area of the piston is one square inch, with the confined fluid, what PSI pressure will be produced? Note that this pressure is exerted in every direction
2. With a 10 square in piston, how much weight will this system lift?
This principle is what allows us to multiple our work efforts. With one lb of down pressure, we are able to lift 10 lbs.
--Pressure is caused by a resistance to flow. In this case the 10 lb weight.
Point out that resistance to flow is what causes pressure. In this example, if there were a 100 lb weight on the right side (in place of the 10 lb weight), how much pressure would be required to lift it. (10 PSI).
1 psi
(6.9kpa) 11
Hydraulic Fundamentals

12. THE TWO MAIN TYPES OF PUMPS:
THE TWO MAIN TYPES OF PUMPS:
1. With a positive displacement pump, with each revolution, a specific
amount of fluid is pumped somewhere.
2. The non-positive pump can rotate all day and not necessarily cause
fluid to flow.
Thus the positive displacement pump is used in applications that
require higher pressures and the non-positive displacement pumps are
used in applications that require high volumes (flow rates).
Hydraulic Fundamentals

13. Pump Types Positive Displacement
Pump 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
The two main types of Pumps
1. With a positive displacement pump, with each revolution, a specific amount of fluid is pumped somewhere.
2. The non-positive pump can rotate all day and not necessarily cause fluid to flow
… Thus the positive displacement pump is used in applications that require higher pressures and the non-positive displacement pumps are used in applications that require high volumes (flow rates) 13
Hydraulic Fundamentals

14. JIC Symbols Joint Industry Council
Symbolic Drawings used in Schematics to Represent Components.

15. J I C Symbols Joint Industrial Council
J I C Symbols Joint Industrial Council
2139 Wisconsin Ave, NW Washington, DC This organization was founded in JIC standards replaced those written by the Joint Industrial Conference (mostly auto manufacturing)
BUILDS 1. Circle, the major components in a JIC schematic are circles. For a pump with start with a circle.
2. Then we add an arrow head. The arrow pointing out of the circle signifies the direction of the fluid flow. OUT, indicating a pump
3. Continue to build showing two arrows heads, meaning this pump is capable of pumping oil in two directions
4. The arrow signifies that this pump is capable of varying the amount of flow, so it is a variable displacement pump.
Hydraulic Fundamentals

16. Pumps (JIC Symbols) Constant Displacement Single Direction
Pumps (JIC Symbols)
Constant Displacement Single Direction
Arrow Showing Oil Flow OUT
Bi-Directional, Variable Displacement
J I C Symbols Joint Industrial Council
2139 Wisconsin Ave, NW Washington, DC This organization was founded in JIC standards replaced those written by the Joint Industrial Conference (mostly auto manufacturing)
BUILDS 1. Circle, the major components in a JIC schematic are circles. For a pump with start with a circle.
2. Then we add an arrow head. The arrow pointing out of the circle signifies the direction of the fluid flow. OUT, indicating a pump
3. Continue to build showing two arrows heads, meaning this pump is capable of pumping oil in two directions
4. The arrow signifies that this pump is capable of varying the amount of flow, so it is a variable displacement pump.
Lastly, ask the students based on the symbols shown, what type of pump is this?
Then ask, what configuration of pump is capable of variable displacement and pumping in two directions?
Pumps convert mechanical power into hydraulic force 16
Hydraulic Fundamentals

17. “Heavy Duty” applications that require variable displacement
“Heavy Duty” applications that require variable displacement
bi-directional pumps, typically use axial piston pumps.
POINT OUT THE:
1. Rotating group
2. Swash plate
3. Pistons
Hydraulic Fundamentals

18. Axial Piston Pump Neutral Position Vertical Swashplate Pressure Oil
Axial Piston Pump
Neutral Position Vertical Swashplate
Pressure Oil
Each Piston
Piston
Engine Shaft Pumps
Piston
“Heavy Duty” applications that require variable displacement bi-directional pumps, typically use axial piston pumps.
Point out the:
1. Rotating group
2. Swash plate
3. Pistons
Piston
Rotating Group Typically 9 Pistons
Swash Plate 18
Hydraulic Fundamentals

19. SWASHPLATE ANGLE, FORWARD POSITION:
SWASHPLATE ANGLE, FORWARD POSITION:
1. As the hydro linkage is slowly moved forward (swashplate angle
changes) the vehicle starts to move forward.
2. The movement of the swashplate controls the direction of the motor
rotation.
3. When the swashplate is moved further forward (swashplate angle
increases), the piston assemblies start to travel further, generating
more flow, more oil is being pumped and the speed of the
vehicle is increased.
4. Flow rate is determined by length and frequency of strokes.
When full swashplate travel is reached (maximum swashplate
angle), the maximum volume of oil is being discharged from the
pump, then the speed of the motors are at maximum.
Hydraulic Fundamentals

20. Axial Piston Pump Forward Position Angled Swashplate Charge Oil
Axial Piston Pump
Forward Position Angled Swashplate
Charge Oil
Swashplate Angle Forward Position
As the hydro linkage is slowly moved forward the vehicle starts a forward movement. The movement of the swashplate controls the direction of the motor rotation. When the swashplate is moved further, the piston assemblies start to reciprocate further, generating more flow, more oil is being pumped and the speed of the vehicle is increased. Flow rate is determined by length of and frequency of strokes (RPM). When full swashplate angle is reached, the maximum volume of oil is being discharged from the pump the speed of the motors are at the greatest.
Pressure
Rotating Group Typically 9 Pistons 20
Hydraulic Fundamentals

21. Axial Piston Pump Reverse Position Angled Swashplate Pressure Charge
Axial Piston Pump
Reverse Position Angled Swashplate
Pressure
In the reverse position, the pump shaft still rotates in the same direction, but the discharge of oil from the pump is reversed, thus reversing the motor rotation.
Charge
Rotating Group Typically 9 Pistons 21
Hydraulic Fundamentals

22. Before going back into JIC symbols, lets show another very popular
Before going back into JIC symbols, lets show another very popular
type of pump or motor.
1. What clues might we have to determine whether this device is a
pump or a motor?
NOTE: Typically, a pump will have a larger INLET opening.
2. If this were a Pump and with the pump turning in the direction
illustrated by the arrows, which side is the inlet and which side is
the outlet?
Build shows inlet and outlet.
Hydraulic Fundamentals

23. In Out Gear Pump or Motor 23
Gear Pump or Motor In
Out
Before going back into JIC symbols, lets show another very popular type of pump or motor.
1. What clues might we have to determine whether this device is a pump or a motor.
NOTE: Typically, a pump will have a larger INLET opening.
2. If this were a Pump and with the pump turning in the direction illustrated by the arrows, which side is the inlet and which side is the outlet.
Build shows inlet and outlet 23
Hydraulic Fundamentals

24. 1. Circle; as mentioned some of the major components in the hydraulic
BUILDS:
1. Circle; as mentioned some of the major components in the hydraulic
schematic are shown as circles.
2. Add an arrow head, but note how this arrow head differs from the
pump shown earlier .. it points “IN”.
3. Second circle with arrowhead.
This arrowhead comes down from the top.
Does this signify any difference? (NO).
4. Second arrowhead.
What type of motor is this? (bi-directional)
Hydraulic Fundamentals

25. Motors (JIC Symbols) Single Direction Bi-Directional
Motors (JIC Symbols)
Single Direction
Bi-Directional
Arrow Showing Oil Flow IN
BUILDS
1. Circle, as mentioned some of the major components in the hydraulic schematic are circles
2. Add an arrow head, but note how this arrow head differs from the pump shown earlier .. it point “IN”
3. Second circle with arrowhead. This arrowhead comes down from the top. Does this signify any difference? NO.
4. Second arrowhead
5. What type of motor is this, bi-directional
Motors used in turf equipment are typically fixed displacement type delivering a constant output torque for a given pressure throughout the speed range of the motor.
Motors converts hydraulic force into mechanical power 25
Hydraulic Fundamentals

26. Reservoirs 1. Vented 2. Pressurized 3. Return Above Fluid Level
Reservoirs
1. Vented
2. Pressurized
3. Return Above Fluid Level
4. Return Below Fluid Level 26
Hydraulic Fundamentals

27. Lines and Connections or Working Line (Main) Crossing Lines
Crossing Lines or
Working Line (Main)
Pilot Control Line
Connecting Lines
Drain Line
Standard pipe ID is larger than nominal size.
Steel and Copper tubing size indicates the OUTSIDE diameter.
Flexible Line
Flow Direction 27
Hydraulic Fundamentals

28. Check Valve Checked Flow Free Flow Spring Assisted Pilot Operated 28
Check Valve
Checked Flow
Free Flow
Spring Assisted
Pilot Operated 28
Hydraulic Fundamentals

29. Relief Valves Protects the Pump and Lines from excessive pressure
Returns fluid back to the reservoir

30. Relief Valve Supply Return to Reservoir Pilot supply 30 2017-04-28
Hydraulic Fundamentals

31. Pressure Differential Valve
Pressure Differential Valve
Supply
Senses the DIFFERENCE in Pressure 31
Hydraulic Fundamentals

32.
Manual On/Off Valve 32
Hydraulic Fundamentals

33. Fluid Conditioners Filter Oil Cooler 33 2017-04-28
Hydraulic Fundamentals

34. Filters Micron 1 Millionth of a Meter or 1 Thousandth of a Millimeter
Filters
Internal Filter Bypass Valve (Optional)
Micron
1 Millionth of a Meter or 1 Thousandth of a Millimeter 34
Hydraulic Fundamentals

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)

36. Hydraulic Valve JIC Closed Center Hydraulics
Hydraulic Valve JIC
Closed Center Hydraulics
Open Center Flow in Neutral
Trapped Oil
Open Center Valve
Hydraulic flow continually moves through the system because the hydraulic pump is constantly pumping fluid. The valve is open to return in neutral to allow the fluid to circulate back to the reservoir.
Oil is drawn out of the reservoir because atmospheric pressure (14.7 psi) pushes it through the lines into the pump. 36
Hydraulic Fundamentals

37. 1. Hydraulic flow continually moves through the system.
OPEN CENTER VALVE:
1. Hydraulic flow continually moves through the system.
2. The hydraulic pump is constantly pumping fluid.
3. The control valve is open to return in neutral to allow
the fluid to circulate.
Hydraulic Fundamentals

38.
Hydraulic Valve JIC
Extend 38
Hydraulic Fundamentals

39.
Hydraulic Valve JIC
Retract 39
Hydraulic Fundamentals

40.
Hydraulic Valve JIC
Neutral Again 40
Hydraulic Fundamentals

41.
Let’s examine what happens when a cylinder is extended. Pressure oil is routed to the piston end. Oil from the rod end is allowed to return to the reservoir.
Hydraulic Fundamentals

42.
Lift Cylinder
Extend
Let’s examine what happens when a cylinder is extended. Pressure oil is routed to the piston end. Oil from the rod end is allowed to return to the reservoir.
Hydraulic Fundamentals

43. This IS NOT TRUE!! So where does the hydraulic oil go?
When cylinders “leak down” over a period of time, it is commonly believed that the cylinder piston “packings” (O-ring seals) are the cause of the problem.
This IS NOT TRUE!! So where does the hydraulic oil go?
Hydraulic Fundamentals

44. Lift Cylinder Leak Down Where Does the Oil Go??
Lift Cylinder
Leak Down
Where Does the Oil Go??
When cylinders “leak down” over a period of time, it is commonly believed that the cylinder piston “packings” (O-ring seals) are the cause of the problem. This IS NOT TRUE!! So where does the hydraulic oil go?
Hydraulic Fundamentals

45.
This illustration goes beyond the practical but makes the point. Because of the volume of oil trapped in the cylinder, the rod CANNOT retract any further unless the trapped oil is allowed to escape somewhere. In this case and always with cylinders that leak down by retracting, the control valve is leaking allowing the oil out of the cylinder.
Remember, this rule applies only when the cylinder rod retracts (oil leaking from the piston end to the rod end and out through the control valve). Oil can leak from the rod side to the piston side (allowing the rod to extend) because the rod side with less volume of oil can leak into the piston side with a greater area.
Hydraulic Fundamentals

46.
Lift Cylinder
Is it Possible for This Rod to Retract Even With the Piston Removed??
This illustration goes beyond the practical but makes the point. Because of the volume of oil trapped in the cylinder, the rod CANNOT retract any further unless the trapped oil is allowed to escape somewhere. In this case and always with cylinders that leak down by retracting, the control valve is leaking allowing the oil out of the cylinder.
Remember, this rule applies only when the cylinder rod retracts (oil leaking from the piston end to the rod end and out through the control valve). Oil can leak from the rod side to the piston side (allowing the rod to extend) because the rod side with less volume of oil can leak into the piston side with a greater area.
Hydraulic Fundamentals

47. Cylinder Hose Failures
Cylinder Hose Failures
Effects On Line Pressure When a Cylinder Piston Packing is Leaking
15000 lbs of Down Force
1.5” Diameter Rod .75 x .75 x = 1.77 sq.in. Results in 8475 PSI
This illustration goes beyond the practical but makes the point. Because of the volume of oil trapped in the cylinder, the rod CANNOT retract any further unless the trapped oil is allowed to escape somewhere. In this case and always with cylinders that leak down by retracting, the control valve is leaking allowing the oil out of the cylinder.
Remember, this rule applies only when the cylinder rod retracts (oil leaking from the piston end to the rod end and out through the control valve). Oil can leak from the rod side to the piston side (allowing the rod to extend) because the rod side with less volume of oil can leak into the piston side with a greater area.
3” Diameter Piston 1.5 x 1.5 x = 7.07 sq.in. Results in 2122 PSI
Hydraulic Fundamentals

48.
To test a cylinder for internal leakage (past the piston seals), remove the cylinder pin from the rod (what ever the cylinder works on will have to be supported). Either extend or retract the rod completely. Then remove the oil line closest to the cylinder’s internal piston. Connect a hydraulic hose to the cylinder where the line was removed. Place the other end of the hydraulic hose in a clean bucket. Pressurize the opposite side of the cylinder with hydraulic oil. Measure leakage into the bucket. If excessive leakage is observed into the bucket, replace cylinder piston seals.
NOTE: On some systems, such as the John Deere light weight fairway mowers, the line returning the lift valve will need to be capped to prevent return oil from flowing out the line.
Hydraulic Fundamentals

49. Hydraulic Cylinder Leakage Test
Hydraulic Cylinder Leakage Test
Depending on the System, You May Have to Cap This Line To Prevent Return Oil From Leaking Out
To test a cylinder for internal leakage (past the piston seals), remove the cylinder pin from the rod (what ever the cylinder works on will have to be supported). Either extend or retract the rod completely. Then remove the oil line closest to the cylinder’s internal piston. Connect a hydraulic hose to the cylinder where the line was removed. Place the other end of the hydraulic hose in a clean bucket. Pressurize the opposite side of the cylinder with hydraulic oil. Measure leakage into the bucket. If excessive leakage is observed into the bucket, replace cylinder piston seals.
NOTE: On some systems, such as the John Deere light weight fairway mowers, the line returning the lift valve will need to be capped to prevent return oil from flowing out the line.
Retract 49
Hydraulic Fundamentals

50. JIC Symbols Build the System Would This Hydraulic Drive System Work?
Would This Hydraulic Drive System Work? PM
Common Reservoir
Yes, In one direction
Hydraulic Drive Does NOT Provide Dynamic Braking
Build the System 50
Hydraulic Fundamentals

51. JIC Symbols Closed Loop Hydrostatic Transmission PM Hill Simulation 51 PM
Hill Simulation
Closed Loop Hydrostatic Transmission 51
Hydraulic Fundamentals

52. JIC Symbols Closed Loop Hydrostatic Transmission PM Hill Simulation 52 PM
Hill Simulation
Closed Loop Hydrostatic Transmission 52
Hydraulic Fundamentals

53. JIC Symbols Build the System PM Oil Filter Oil Cooler Inlet Check
Oil Filter
Inlet Check PM
Common Reservoir
Inlet Check
Build the System
Oil Cooler 53
Hydraulic Fundamentals

54. 1. Oil cooler bypass will open with a differential of 80-130 PSI
Both the Oil Cooler Bypass and Oil Filter Bypass are “Differential Relief Valves” which have the capability of comparing pressures on the inlet side and the pressure on the outlet side; On the 3365 WARM, these reliefs open:
1. Oil cooler bypass will open with a differential of PSI
2. Filter bypass will open with a differential of PSI
Leak off lines are NOT shown, but are required to provide;
1. Lubrication
2. Cooling
3. Cleaning
Hydraulic Fundamentals

55. JIC Symbols Build the System PM Oil Filter Oil Cooler 55
Oil Filter
Oil Cooler Bypass Valve PM
Charge Relief Valve
Filter Bypass Valve
Build the System
Oil Cooler 55
Hydraulic Fundamentals

56. This slide shows normal oil flow;
This slide shows normal oil flow;
1. Hydro turns providing oil flow to motors.
2. Motors turn, some oil is lost to case drain
3. Charge pump provides oil flow through;
Cooler
Filter
Inlet Check Valves
Hydraulic Fundamentals

57. JIC Symbols Hydrostatic Transmission Components PM Oil Filter PM
JIC Symbols
Oil Filter
Oil Cooler Bypass Valve
Charge Relief Valve
Both the Oil Cooler Bypass and Oil Filter Bypass are “Differential Relief Valves” which have the capability of comparing pressures on the inlet side and the pressure on the outlet side; On the 3365 WARM, these reliefs open:
1. Oil cooler bypass will open with a differential of PSI
2. Filter bypass will open with a differential of PSI
Leak off lines are NOT shown, but are required to provide;
1. Lubrication
2. Cooling
3. Cleaning
Filter Bypass Valve
Hydrostatic Transmission Components
Oil Cooler 57
Hydraulic Fundamentals