The file contains all details of Hydraulic pump motors and actuators. This is the part of the subject Oil Hydraulic and Pneumatic in GTU in 7th semester.

1. Hydraulic Pumps,
Motors and Actuators
Faculty Name: Prof. Ajaypalsinh G. Barad
Branch: Mechanical
College : S. P. C. E., Visnagar
Semester: 7th Semester
Name of Subject: Oil Hydraulic and Pneumatic

2. Outline
• Concept
• Rotary Pumps
• Reciprocating Pumps
• Vane characteristics
• Generated-Rotor characteristics
• Screw characteristics
• Axial Piston characteristics
• Radial Piston characteristics
• Linear and Rotary Actuators
• Hydrostatic Transmission Systems
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3. Concept:
• Classification of Pump:
– Positive Displacement Pump
– Non Positive Displacement Pump
• Positive Displacement Pump (PDP):
– The displacement is positive, means irrespective of increase
in pressure the pump discharge remains same.
– As hydraulic systems have to develop large amount of force,
only PDP can be used to deliver discharge under high
pressure.
– Rotary pump
– Reciprocating pump.
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4. Concept:
• Non Positive Displacement Pump (NPDP):
– Discharge does not remain constant.
– With increase in pressure discharge reduces and at
maximum pressure it is becomes zero.
– Oil can not be deliver by pump at high pressure.
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5. Concept:
• PDP can pump oil at high pressure,
– The moving component carries the liquid
– As moving component moves, liquid has to move with it.
– In NPDP, the high speed moving component gives off its
kinetic energy to the liquid and with the KE it moves from
inlet to outlet.
– In case of high pressure, opposing pressure at outlet is more
due to that liquid can not move and starts rotating within the
casing.
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6. Concept:
• Reasons for not using Reciprocating pump,
– It has more number of moving components, piston, crank,
connecting rod, valve.
– Due to which cost, size and maintenance is more.
– Also strong foundation required to sustain vibration.
– Fluctuating load, flywheel is required.
– Overall size of plant increases and machine becomes bulky.
– Discharge during delivery stroke and no discharge during
suction stroke.
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7. Concept:
• Reasons for preferring Rotary pump,
– Rate of flow remains constant.
– No fluctuating loads so no need of flywheel.
– Discharge is smooth and not pulsating.
– Very less vibration and noise. No need of strong foundation.
– Due to lesser parts, pumps are very compact.
– Cost is comparatively less.
– Easy maintenance and less maintenance cost.
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8. Comparison between PDP and NPDP :
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9. Classification of Rotary Pumps :
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10. External Gear Pump :
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11. Internal Gear Pump :
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12. Lobe Pump :
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13. Generated Rotor Pump :
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14. Screw Pump :
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15. Unbalanced Vane Pump :
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16. Variable Displacement Vane Pump :
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17. Balanced Vane Pump :
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18. Straight Axis Piston Pump :
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19. Straight Axis Piston Pump :
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20. Straight Axis Piston Pump :
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21. Straight Axis Piston Pump :
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22. Straight Axis Piston Pump :
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23. Straight Axis Piston Pump :
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24. Bent Axis Piston Pump :
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25. Stationary Cylinder Radial Piston Pump :
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26. Rotating Cylinder Radial Piston Pump :
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27. Selection Criteria for Hydraulic Pump :
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28. Comparison between Gear, Vane and Piston Pump:
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Construction
• Gear : consist of two gears in mesh with each other,
mounted inside a closed casing. One is driver and the
other is driven.
• Vane : consist of cylindrical rotor with radial slots.
Vanes are inserted in the slots. The rotor is mounted
with an offset in the casing.
• Piston : consist of a cylindrical block with axial or
radial bores. Pistons are inserted in the bores. One end
of the piston is connected to rotating component.
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29. Comparison between Gear, Vane and Piston Pump:
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Working :
• Gear : driver is rotated by means of prime mover that
rotates driven. The oil is sucked, trapped and carried
from inlet to outlet.
• Vane : rotor causes the size of the pockets to grow and
reduce alternately. This causes filling of oil on suction
side and delivery on the other side.
• Piston : rotation of the moving component causes the
pistons to reciprocate in the bores. Half rotation of the
cylinder block causes suction of oil into the bores and
the next half causes discharge.
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30. Pump Calculations :
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31. Pump Calculations :
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32. Pump Calculations :
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33. Pump Calculations :
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34. Pump Calculations :
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The displacement of a pump operating at 1000 rpm at
a pressure of 70 bar is 100 cm3. the input torque is
120 N-m. if the pump delivers 0.0015 m3/s of oil,
find : (1) Overall efficiency, (2) Theoretical torque.
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35. Pump Calculations :
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36. Actuators :
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• Actuators are those components of a fluid power
system, which produces mechanical work output.
• They develop force and displacement, which is required
to perform any specific task. The task may be of any
kind, to move, to press, to lift, to clamp.
• Actuators are common for both hydraulic and pneumatic
system.
• Hydraulic actuators are made stronger to with stand
pressure of oil and develop huge amount of force.
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• Speed of actuator depends on rate of working fluid.
Rate of flow of working fluid can be controlled using
Flow Control Valve (FCV).
• Force developed by cylinder is the product of pressure
of working fluid and the piston area.
• Force of actuator is controlled by controlling the
pressure of working fluid using Pressure Control Valve
(PCV).
• Direction of motion of actuator is controlled by
controlling the direction of flow of fluid, by using
Direction Control Valve (DCV).
Actuators :
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38. Actuators :
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• Actuators are of two types:
– Linear actuator
– Rotary actuator
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39. Actuators :
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• Linear actuator
– Rotating cylinder
– Non rotating cylinder
• Single acting cylinder
• Double acting cylinder
– Special type cylinder
• Diaphragm cylinder
• Tandem cylinder
• Double rod end cylinder
• Telescopic cylinder
• Cylinder with cushioning
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40. Actuators :
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• Rotary actuator
– Limited rotation actuators
• Vane type
• Piston type
– Continuous rotation actuators
• Based on direction
– Uni-directional motors
– Bi-directional motors
• Based on construction
– Gear type
– Vane type
– Piston type
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41. Linear actuator :
Rotating cylinder :
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42. Non Rotating Cylinder :
Single acting cylinder :
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Non Rotating Cylinder :
Double acting cylinder :
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Special type Cylinder :
Diaphragm cylinder :
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Special type Cylinder :
Tandem cylinder :
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Special type Cylinder :
Double Rod End cylinder :
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Special type Cylinder :
Telescopic Cylinder :
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Special type Cylinder :
Cylinder with Cushioning :
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Cylinder Mountings :
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Cylinder Mountings :
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Cylinder Mountings :
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Vane Type Motor:
Rotary Actuator :
Limited Rotation Actuators :
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Piston Type Motor:
Rotary Actuator :
Limited Rotation Actuators :
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Rotary Actuator :
Continuous Rotation Actuators :
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Rotary Actuator :
Continuous Rotation Actuators :
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Rotary Actuator :
Continuous Rotation Actuators :
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Rotary Actuator :
Continuous Rotation Actuators :
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Rotary Actuator :
Continuous Rotation Actuators :
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Rotary Actuator :
Continuous Rotation Actuators :
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Motor calculations :
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Motor calculations :
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Motor calculations :
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Motor calculations :
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64. Comparison between Hydraulic Pump and Motor :
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Hydraulic Pump Hydraulic Motor
Pumps the hydraulic oil to
system
Produces rotation and torque
Mechanical energy converted
into hydraulic energy
Hydraulic energy converted
into mechanical energy
Work consuming device Work producing device
Construction of pump and motor are similar so both can be
used in place of one other.
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65. Hydraulic
Transmission :
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66. Hydraulic Transmission : :
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Advantages :
• No need to apply clutch and gear.
• Controlled speed is possible in both direction
• Speed can be set to any value
• Single liver is used to control speed and direction
• Low maintenance
• High pressure oil can be used for power steering
• Less response time compared to gear transmission
• Power loss due to friction is minimized
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67. Hydraulic Transmission : :
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Disadvantages :
• More expensive
• Lower efficiency compared to mechanical transmission
• Cannot be towed, may damage the pump.
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