Basic principle and working of a Hydraulic system of Tractor.

1. TERM PAPER ON:
HYDRAULIC SYSTEM
PRESENTED BY:
GOPAL CARPENTER
12-543-008

2. The term hydraulics is
Hydor+aulos
Hydor –means water
Aulos- pipe

3. Necessity of hydraulics:
1.To lift or load the implement
2.To set the draft at the time of tillage operations

4. Pascal’s Law
Pressure exerted at any point on
a confined liquid is transmitted
undiminished in all directions.

5. Pressure applied to piston “A” is
transferred equally to a piston of the same
size “B” because PSI is the same
throughout the system.
Basic
principle

6. Pascal’s Law
 Pressure applied to a
confined fluid is:
 transmitted undiminished in
all directions,
 acts with equal force on equal
areas, and
 acts at a right angle to the
walls of the container.
10 psi
10-lb
1 in2
Area = 10 in2
Force = 100-lbs.

7. Important Properties:
 “Shapelessness”
 Liquids have no neutral form
 Conform to shape of container
 Easily transferred through piping from one location
to another
 Incompressibility
 Liquids are essentially incompressible
 Once force is removed, liquid returns to original
volume (no permanent distortion)
 Transmission of Force
 Force is transmitted equally & undiminished
in every direction -> vessel filled with pressure

8. Components of hydraulics:
1.Reservoir
2.Hydraulic
pump
3.Hydraulic
cylinder
4.Hydraulic
piston
5.Control valve
6.Relief valve

9. Hydraulic circuit:
A hydraulic circuit is a system comprising
an interconnected set of discrete
components that transport liquid.

10. Pump
Functions in a hydraulic
system by pressurizing
and moving fluid from one
part of the system to
another.

11. Hydraulic pumps are usually of three
types:
1. GEAR PUMP
2. PISTON PUMP
3. VANE PUMP

12. Gear Pumps:
 Fixed or constant displacement pump.
 Work well at 1500 psi and below
 Work with a minimum of moving parts
 Less expensive to manufacture than piston
type pumps

13. Gear
Pump driven gear
idler gear

14. Piston Pumps
 Work well at 2000 psi or more.
 Require several pistons working together to
generate enough volume for tractor
applications
 Necessarily involve many moving parts
 Two types-1.Axial piston pump
2.Radial piston pump

15. Vane pump
 Also works at 1500 psi and below
 Three types-1.sliding vane
 2.swinging vane 3.Rolling vane

16. Hydraulic Cylinders:
 The main function of a cylinder is to convert hydraulic
power into linear mechanical force.
 This force performs work or transmits power.
 Types : 1.Ram cylinder
2.Single Acting
3.Telescopic
4.Spring Return
5.Double Acting

17. Ram Cylinders:
 The simplest single acting cylinder
 One fluid chamber
 Exerts force in only one direction
 Mounted mostly vertically
 The cylinder retracts by the force of the load
due to gravity
 Ram cylinders are most commonly used in
elevators, jacks, and automobile hoists.

18. Single Acting Cylinders:
 Acts much like a ram cylinder
 Main difference is that the single acting cylinder uses a
piston. The leakage flow that goes past the piston is
ported the tank.
Telescopic Cylinders:
• Mostly a single acting cylinder
• Series of rod segments called sleeves, most common to only
have 4 or 5 sleeves in each cylinder
• The sleeves work together to provide a longer stroke
• The maximum force is at the collapsed position
• The speed will increase at each stage, but will not allow as
much force.

19. Spring Return Cylinders:
 Considered a single acting cylinder
 Pressure applied to the cap end pushes the spring down as
the rod is extending
 When the pressure is removed the spring force allows the
cylinder to retract
 The drain is in the spring chamber and allows the leakage
flow past the piston seal

20. Double Acting Cylinders:
 Types:-1.Double acting (differential cylinder)
 2.Double rod cylinder (nondifferential cylinder)
3.Tendom
 Pressure is applied to both rod end and cap end
 Rod extension is slower because has a larger area,
but allows a greater force because of the bigger
area.
 Retract is faster because of the smaller area, but
the force allowed is smaller because of the smaller
area.

21. Double Acting Cylinders:
Tandem Cylinder-
 Two pistons in line with a common rod
 This allows you to have a greater forces without
increasing the size of the cylinder bore
 Tandem cylinders are used in places where
there is insufficient space to increase the size of
the cylinder bore.

22. Control valves:
 Functions of a valve:-
1.direct the flow of fluid
2.regulate the pressure
3.control volume
Three types of valves:
 Pressure – adjust psi for some purpose
 Directional -- route the fluid to the desired actuator
 Volume Control or Flow Control -- control the
amount of flow

23. Accumulators:
 Types:-
 Piston
 Most common
 Bladder
 Gun mounts
 Steering
systems
 Direct contact
 Least common

24. Hydraulic oil:
 Purposes:-
1.Compressibility
2.Lubrication
3.Sealing
4.Cooling

25. 10/6/2015 25
Fluid Properties:
 These properties include:
 Viscosity and Viscosity Index
 Pour Point
 Specific gravity
 Thermal properties- specific heat & thermal
conductivity
 Lubricating Ability
 Rust and corrosion protection
 Fire resistance

26. Filters:
Hydraulic lines:

27. Hydraulic system types:
 Open center system.
 Closed center system.

31. Basic Hydraulic System Operation
Pump
Directional
Control
Valve
Cylinder
Reservoir
Pressure
Relief
Valve

32. Hydraulic