Hydraulic actuators are used to convert hydraulic pressure into mechanical motion or force. The main types are linear actuators like hydraulic cylinders, rotary actuators like motors, and semi-rotary actuators. Hydraulic cylinders come in single-acting, double-acting, telescopic, and tandem varieties. Double-acting cylinders use hydraulic pressure on both sides of the piston to extend and retract the rod. Telescopic cylinders extend in stages for a long stroke and short retracted length. Tandem cylinders apply pressure to multiple pistons to produce increased force from a small cylinder diameter. Cushioning devices are used on cylinders to control deceleration and prevent shock at the end of the stroke.
The document discusses various types of hydraulic accumulators and components. It describes weight loaded, spring loaded, and gas loaded accumulators. It also explains intensifiers, which convert low pressure fluid into high pressure fluid. Additionally, it discusses servo valves, proportional valves, and various industrial hydraulic circuits like regenerative circuits and pump unloading circuits.
This document discusses hydraulic accumulators. It defines an accumulator as an energy storage device that uses an external force like a spring or compressed gas to apply pressure to a non-compressible fluid. It then describes the main types of accumulators - dead weight, spring loaded, and compressed gas. Compressed gas accumulators are further broken down into bladder, diaphragm, piston, and metal bellow types. The document also covers the functions of accumulators in applications and considerations for accumulator sizing and selection.
In hydraulic and pneumatic systems flow control valves are necessary to vary the speed of actuator. Flow control valves are placed in between Actuator and Direction Control (DC) Valve
The pressure energy is fed to the actuator through a number of control block called valves.
• Various type of valve are used in hydraulic system to control or regulate the flow medium.
• Basicallyvalvesareexpectedtocontrol: – Direction
– Pressure
– Flow
– Otherspecialfunctions.
This document discusses hydraulic cushions used to slow the movement of pistons near the end of their stroke in cylinders. It describes how cushions work by restricting oil flow through an adjustable opening to decelerate the piston. Ideal cushioning is defined as stopping the piston's velocity exactly at the end of its stroke with minimal noise and vibration. This can be achieved by properly adjusting the cushioning screw to maximize kinetic energy absorption. The document provides tips on correcting overdamping and underdamping, and outlines design considerations like piston velocity and mass ratios to achieve ideal cushioning.
Pumps are mechanical devices that use prime mover energy to move fluids from one place to another. Positive displacement pumps apply pressure directly to the liquid using reciprocating or rotating components. The main types of positive displacement pumps are reciprocating pumps like piston pumps and diaphragm pumps, and rotary pumps like gear pumps. Reciprocating piston pumps use oscillating pistons to move fluid, and can be single or multi-cylinder designs. Axial and radial piston pumps use rotating cylinders to pump fluid. Diaphragm pumps use a reciprocating rubber diaphragm and check valves to pump fluid on each stroke. Positive displacement pumps are suitable for high-pressure applications and handling viscous or abrasive fluids.
1) A hydraulic accumulator stores hydraulic fluid under pressure to reduce pressure fluctuations and smooth out demand. It uses an external force like compressed gas, springs or raised weights to apply pressure.
2) The first accumulators were water towers built in the 1800s to provide constant pressure for cranes and locks. Common accumulator types are compressed gas, springs, and raised weights.
3) Accumulators provide benefits like dampening pressure spikes, compensating for leaks, absorbing thermal expansion, and improving response times. They are used in agricultural, construction, mining and other heavy machinery.
The document discusses hydraulic symbols according to ISO 1219 standards, including symbols for hydraulic pumps and motors, actuators like cylinders, directional control valves, pressure control valves, flow control valves, check valves, and other accessories. It provides information on the functions of different hydraulic components like pumps converting mechanical to hydraulic energy, motors converting hydraulic to mechanical rotation, cylinders providing linear motion, and various valve types controlling direction, pressure, and flow within hydraulic circuits.
This document discusses low cost automation using pneumatic systems. It begins with an overview of automation and pneumatics, explaining that pneumatics can provide low cost automation solutions through reducing labor costs, machine investment costs, and increasing productivity. The document then covers various pneumatic components and applications, advantages and disadvantages of pneumatics, pneumatic standards, classifications of pneumatic elements, and examples of pneumatic circuits.
The document provides an overview of hydraulics actuation systems used in heavy machinery. It discusses how fluid power works through Pascal's law and hydraulic leverage to amplify force. Key components of hydraulic systems are described, including reservoirs, filters, pumps, motors, accumulators, cylinders, and control valves. Common applications like earthmoving equipment, presses, and rollercoasters are highlighted. Diagrams illustrate the configuration and flow of components in hydraulic circuits.
This document provides an overview of hydraulic actuators and motors. It begins with learning objectives and introduces different types of hydraulic actuators, including linear actuators like cylinders and rotary actuators. It then describes the construction and working of various types of hydraulic cylinders and motors, including single acting cylinders, double acting cylinders, gear motors, vane motors, and piston motors. It also discusses topics like the comparison between pumps and motors, mechanics of hydraulic cylinder loading using different lever systems, and classifications of hydraulic motors.
The document discusses hydraulic accumulators, which store hydraulic energy as pressure energy to be supplied intermittently for applications requiring bursts of energy. It describes the basic components and working of a hydraulic accumulator, which consists of a cylinder containing a sliding ram that stores energy by lifting a weight as hydraulic fluid enters under pressure. The capacity of an accumulator depends on the pressure, area of the ram, and stroke/lift. Differential accumulators store energy at higher pressures using a smaller ram area and annular space between cylinders.
Cams are used to convert rotary motion to oscillatory motion or vice versa. They are commonly used in internal combustion engines to operate valves. This chapter discusses the fundamentals of cam and follower design including the different types of cams, followers, motions, and cam profiles. The objectives are to understand basic concepts and terminology and learn how to design a cam and follower set to achieve a desired output motion.
The major components of a hydraulic system are:
1. A prime mover such as an engine or electric motor that provides mechanical power.
2. A pump that is driven by the prime mover to pressurize the fluid and convert mechanical energy to fluid energy.
3. Control valves such as pressure, flow, and directional valves that control the flow and direction of pressurized fluid.
4. Actuators that convert pressurized fluid power into mechanical motion or force.
5. A piping system that carries pressurized fluid between components and back to the reservoir.
Hydraulic motors use high pressure fluid to turn a shaft. There are several types including gear motors, vane motors, and piston motors. Gear motors use rotating gears where fluid pressure creates force. Piston motors are often the most efficient and used in aerospace due to their high power to weight ratio. Performance is determined by efficiency factors like internal leakage and friction. Calculations can determine required pressure, flow rate, power output, and efficiency.
This is complete description of Hydraulic Accessories used consisting
1.Hydraulic Reservoir or tank- construction, mountings, Design
2.Heaters & coolers- Types
3.Sealing- introduction, classification, each type with diagram, materials, seal selection factors,
4.Piping- intro, sizing of pipe, Pipe Schedules, Threads, Fittings, materials, connectors,
5. Hoses- materials, selection criteria,
6. Accumulators- types, information of each type with diagram,
7. Hydraulic fluids- properties, types
8. Filters- types, specifications, materials
I hope you find this useful.
please comment if have any questions and like this.
This document summarizes different types of gears classified based on their axis of rotation. It describes spur gears that have parallel axes for transferring power between parallel shafts. Helical gears are also discussed, which have twisted teeth oblique to the axis and produce thrust in the axial direction. Rack gears are explained as bars containing teeth that mesh with gears to convert rotary to linear motion. Bevel gears connect perpendicular shafts and can have straight or spiral teeth. Screw gears transmit power between non-parallel and non-intersecting shafts. Finally, worm gears are detailed as providing large reduction ratios using a threaded worm to drive a worm wheel.
Hydraulic cylinders are linear actuators that convert hydraulic pressure into mechanical force and motion. There are several types of cylinders including single-acting, double-acting, and telescopic cylinders. Single-acting cylinders produce force in one direction only, while double-acting cylinders can produce force in both extension and retraction using ports on both sides of the piston. Telescopic cylinders extend in stages to provide a long stroke length and short retracted length. Cushioning devices are often used on cylinders to control the rate of deceleration and prevent shock at the end of the piston stroke.
Hydraulic actuators convert fluid pressure into mechanical motion or force. Common types include single-acting cylinders, which produce force in one direction, and double-acting cylinders, which can produce force in both directions. Single-acting cylinders use either gravity or a spring for return motion, while double-acting cylinders use fluid pressure on both sides of the piston. Other hydraulic actuators include telescopic cylinders for increased stroke and tandem cylinders for applications requiring high force from a compact design. Actuators allow hydraulic systems to transmit and control power through linear or rotational motion.
An actuator is a device that converts energy into motion. Common types of actuators include pneumatic cylinders powered by compressed air and hydraulic cylinders powered by pressurized fluids. Actuators can produce either linear motion in a straight line or rotational motion. Examples of linear actuators are pneumatic cylinders, hydraulic cylinders, screw jacks, and ball screws. Rotary actuators include hydraulic motors. Actuators are widely used in manufacturing applications to move or position components. Common applications include robots, valves, pumps, and switches.
The document discusses various types of hydraulic actuators used to convert fluid pressure into mechanical motion or force. It describes linear actuators like cylinders, which can be single-acting, double-acting, telescopic, or tandem cylinder designs. Rotary actuators and semi-rotary actuators are also discussed briefly. The main focus is on hydraulic cylinders, their components, operating principles, forces involved, and examples of force and power calculations.
This document discusses different types of pumps used for slurry transportation in multiphase flow. It describes centrifugal pumps, axial flow slurry pumps, mixed-flow pumps, co-rotated disk pumps, Archimedes' screw, plunger piston pumps, axial piston pumps, hydraulic ram pumps, air operated double diaphragm pumps, piston-diaphragm pumps, double disc pumps, progressive cavity pumps, orbital lobe pumps, flexible impeller pumps, gear pumps, and peristaltic pumps. For each pump type, it provides details on its operating principles and common applications.
Module 5 hydraulics and pneumatics Actuation systemstaruian
Pneumatic and hydraulic actuation systems: Pneumatic and hydraulic systems actuating systems.
Classifications of Valves: Pressure relief valves, Pressure regulating / reducing valves
Cylinders and rotary actuators.
DCV & FCV: Principle & construction details.
Types of sliding spool valve & solenoid operated.
Symbols of hydraulic elements, components of hydraulic system, functions of various units of hydraulic system.
Design of simple hydraulic circuits for various applications
This document discusses different types of actuators used in mechatronics systems. It describes three main types of actuators: mechanical, electrical, and fluid (pneumatic and hydraulic). For each type, it provides examples and explanations of common varieties. Mechanical actuators convert one type of motion to another using components like screws, wheels, cams, and gears. Electrical actuators include motors that convert electrical energy to motion, such as AC, DC, servo, and stepper motors. Fluid actuators use compressed air or liquid to power cylinders and other devices that perform work through linear or rotary motion. The document also examines components like valves that are used to control fluid flow and pressure in pneumatic and hydraulic
This document describes the basic components of hydraulic and pneumatic systems. It discusses the key components of hydraulic systems which include an oil reservoir, oil pump, pressure relief valve, directional control valve, flow control valve, pressure control valve, and actuators. For pneumatic systems, it outlines the main components as an air compressor, heat exchanger, air dryer, and FRL (filter, regulator, lubricator) unit. It then compares the characteristics of hydraulic and pneumatic systems and provides examples of hydraulic and pneumatic symbols and different types of rotary actuators, valves, and motors used in these systems.
HYDRAULIC POWER GENERATING AND UTILIZING SYSTEMS
Introduction to fluid power system - Hydraulic fluids - functions, types, properties, selection and application.
POWER GENERATING ELEMENTS: Pumps, classification, working of different pumps such as Gear, Vane, Piston (axial and radial), pump performance or characteristics, pump selection factors- simple Problems.
POWER UTILIZING ELEMENTS: Fluid Power Actuators: Linear hydraulic actuators – Types and construction of hydraulic cylinders – Single acting, Double acting, special cylinders like tandem, Rodless, Telescopic, Cushioning mechanism.
Hydraulic Motors, types – Gear, Vane, Piston (axial and radial) – performance of motors.
The document discusses pneumatics components used in automation systems. It describes the process of compressed air generation including air compression, filtering, drying and storage. It also discusses various pneumatic actuators and output devices like cylinders, grippers, and motors that convert compressed air into mechanical motion or force. Valves are described as key components to control pneumatic circuits and air flow. Common types include 2/2 way, 3/2 way, and 5/2 way valves along with methods of actuation.
A fluid coupling uses oil to transmit power between two shafts without a mechanical connection. It consists of a pump impeller on the driving shaft and a turbine runner on the driven shaft enclosed in a housing filled with oil. As the impeller rotates, it moves the oil through the turbine, causing it to rotate and transmit power to the driven shaft. Torque increases with impeller speed. Fluid couplings are used in automotive and aircraft transmissions as well as diesel locomotives.
Hydraulic machines use fluid motion to convert between hydraulic energy and mechanical energy. There are two main types - hydraulic turbines which convert hydraulic energy to mechanical energy, and hydraulic pumps/compressors which convert mechanical energy to hydraulic energy. Pumps are then further classified based on their displacement and pumping motion, with the main types being centrifugal pumps and positive displacement pumps such as gear pumps. Centrifugal pumps use centrifugal force from an impeller to provide continuous flow, while positive displacement pumps eject fixed quantities of fluid per revolution through mechanisms like reciprocating motion or meshing gears.
This document provides an overview of hydraulic cylinders, including their types, construction, operation, ratings, formulas for application, features, and installation/troubleshooting. It describes the main types of cylinders like ram, single acting, telescopic, spring return, and double acting cylinders. It also discusses cylinder construction, actuation, mounting, ratings based on size and pressure, formulas to calculate speed, flow, force and pressure. Key features like seals, cushions, ports and limit switches are explained. Guidelines for cylinder selection, installation and troubleshooting are provided.
This presentation provides an overview of hydraulic control systems. It discusses the basic components including pumps, control valves, actuators, and piping. It describes the functions of various pressure control valves, flow control valves, and directional control valves. It also discusses hydraulic power sources like pumps and actuators like cylinders. In summary, the presentation introduces hydraulic control systems, outlines their major components, and describes the purpose and classification of key valves and actuators used in these systems.
This document discusses reciprocating pumps. It defines a reciprocating pump as a positive displacement pump that takes liquid from a low head and discharges it at a high head in small quantities by adding energy. It works by using a piston inside a cylinder that moves back and forth, creating pressure changes that push liquid through intake and discharge valves. The main components are the piston, crank and connecting rod, suction pipe, delivery pipe, and intake and discharge valves. There are two main types: single-acting pumps which use one stroke, and double-acting pumps which use both strokes. Reciprocating pumps can move liquids at high pressures and are useful for handling viscous liquids or solids, but they produce pulsating flow
Introduction, classification, principle of working and constructional details of vane pumps, gear pumps, radial and axial plunger pumps, screw pumps, power and efficiency calculations, characteristics curves, selection of pumps for hydraulic Power transmission.
- Almost all modern car crushers use a hydraulic press to crush the cars.
-Components of a Hydraulic Control Section.
Throttle valve.
Filter.
Releif valve.
Pump (fixed displacement).
Double acting cylinder.
Tank.
Motor.
Directional control valve(2position/4way).
The document provides an overview of hydraulic cylinders, including their types, construction, operation, ratings, formulas for application, features, and installation/troubleshooting. It describes the main types of cylinders like ram, single acting, telescopic, spring return, and double acting cylinders. It covers cylinder construction details, actuation, mounting, ratings based on size and pressure, formulas to calculate speed, flow and force. It also discusses features such as seals, cushions, stop tubes, ports, and limit switches. The document concludes with guidelines for cylinder installation and troubleshooting.
This document summarizes key concepts from the fluid mechanics and machinery unit, including pumps. It discusses the impact of jets, Euler's equation, theories of rotodynamic machines, efficiencies, velocity triangles, and classifications and working principles of centrifugal pumps, reciprocating pumps, and rotary pumps such as gear pumps, vane pumps, and screw pumps. Specifically, it explains how centrifugal pumps work by imparting velocity and kinetic energy to the fluid using an impeller, and how reciprocating pumps work by trapping fluid in a chamber and forcing it out with a piston. It also categorizes rotary pumps based on their rotating elements.
A servo valve is a directional control valve that can be precisely positioned using an electrical signal to control the amount and direction of fluid flow. Coupled with sensors, servo valves provide very accurate control of position, velocity, or acceleration. Compared to proportional valves, servo valves use closed-loop control for higher accuracy and frequency response but require cleaner fluid and more maintenance. Servo valves are the most sensitive to contamination and require fluid cleanliness of 5 microns or less.
This document discusses different types of hydraulic valves and components. It covers pressure control valves like relief valves, reducing valves, and unloading valves. It also covers direction control valves like check valves, 3/2 valves, 4/2 valves, and 5/2 valves. Additionally, it discusses flow control valves, manual and pilot operated valves, poppet and spool valves, actuators, pipes and hoses, fittings, seals, accumulators, and pressure boosters.
This document discusses pneumatic components and systems. It describes properties of air and compressors used to generate compressed air. It discusses the function of fluid, regulator, and lubricator (FRL) units and common pneumatic components like air control valves, quick exhaust valves, cylinders, and air motors. Applications of pneumatic systems are also listed, such as material handling, drilling, punching, and assembly operations.
This document discusses hydraulic circuits and systems. It describes different types of gas loaded accumulators including non-separator, separator, piston, diaphragm, and bladder types. It lists several applications of accumulators such as damping pulsations and shocks, increasing operational circuit speed, clamping devices, standby power supplies, surge reduction, and vehicle suspension. The document also discusses pressure intensifiers which are used to boost hydraulic system pressure above the pump discharge pressure, finding application where high pressure liquid is needed from a low pressure source, such as hydraulic presses.
This document provides an overview of fluid power systems and hydraulics. It discusses the history and applications of fluid power, including using water wheels and windmills. The key types of fluid power systems are hydraulic and pneumatic. Hydraulic systems use high-pressure liquids like oil while pneumatic systems use compressed gases like air. The document also covers fluid properties, hydraulic components, basics of hydraulics like laminar and turbulent flow, and applications of fluid power systems in construction, mining, agriculture and more.
This document provides an overview of numerical control (NC) and computer numerical control (CNC) systems and programming. It discusses the basic components and types of NC systems, CNC machine construction details, part programming fundamentals, and micromachining processes like wafer machining. The key topics covered include NC axis conventions, CNC drive systems, work holding, automatic tool changers, programming methods, coordinate systems, tool and work offsets, interpolation types, subroutines, canned cycles, and surface micromachining.
This document provides an introduction to computer aided design and manufacturing (CAD/CAM). It discusses the product development cycle, various design processes, and the advantages of concurrent engineering over sequential engineering. It also describes CAD systems and their architecture, as well as computer graphics topics like coordinate systems, 2D and 3D transformations, line drawing algorithms, and viewing transformations. Key CAD applications and benefits are outlined. The document provides details on several CAD and design related topics at a high level.
Introduction to unconventional machining processesgopalkrishnan202
This document discusses unconventional machining processes. It begins with a brief history of machining from ancient hand tools to modern CNC machines. It then covers the limitations of conventional machining when dealing with advanced materials. The rest of the document defines and categorizes various unconventional machining processes including mechanical, electrical, chemical, electrochemical, and thermal-based methods. Specific processes like EDM, laser beam machining, and abrasive water jet machining are described along with considerations for selecting the appropriate unconventional process.
The Control of Relative Humidity & Moisture Content in The AirAshraf Ismail
To many of us Relative Humidity (RH%) & Moisture Content (g/ kg) are confusing terms & we often don't know which one of them to choose in order to highlight our "Humidity" issues!
This post is to briefly address the definition of Relative Humidity, Moisture Content , Moisture Load Sources & Humidity Control Hazard!
Presentation slide on DESIGN AND FABRICATION OF MOBILE CONTROLLED DRAINAGE.pptxEr. Kushal Ghimire
To address increased waste dumping in drains, a low-cost drainage cleaning robot controlled via a mobile app is designed to reduce human intervention and improve automation. Connected via Bluetooth, the robot’s chain circulates, moving a mesh with a lifter to carry solid waste to a bin. This project aims to clear clogs, ensure free water flow, and transform society into a cleaner, healthier environment, reducing disease spread from direct sewage contact. It’s especially effective during heavy rains with high water and garbage flow.
Hate speech detection using machine learningrakeshrocking3
Hate speech detection involves the application of natural language processing (NLP) and machine learning techniques to identify and categorize text that contains harmful, offensive, or discriminatory language targeted towards individuals or groups based on attributes like race, religion, ethnicity, gender, or sexual orientation. The goal is to automate the process of identifying such content to prevent its spread and mitigate its negative impact.
Introduction And Differences Between File System And Dbms.pptxSerendipityYoon
An introduction to file systems and a database management system. This document provides a free powerpoint presentation about the differences between a file system and database management system. Advantages and disadvantages of file system and database management system.
3. ACTUATORS
Hydraulic systems are used to control and transmit power.
A pump driven by prime mover such as electric motor
creates a flow of fluid in which the pressure, directionand
flow rate are controlled by valves
An actuator is used to convert the energy of fluid back into
mechanical power.
The amount of output power developed depends upon the
flow rate, pressure drop across the actuator and its overall
efficiency
Thus they are devices which used to convert pressure
energy of the fluid into mechanical energy.
4. TYPES
Depending on the type of actuation, hydraulic actuators are
classified as,
1. Linear actuator: for linear actuation (hydraulic cylinder)
2. Rotary actuator: for rotary actuation(hydraulic motor)
3. Semi-rotary actuator: for limited angle of actuation (semi-
rotary actuators)
5. HYDRAULIC LINEAR
ACTUATORS
As their name implies, it provides motion in a straight line.
The total movement is a finite amount determined by the
construction of the unit
They are referred to as cylinders, rams and jacks
The function of a hydraulic cylinder is to convert the hydraulic
power into linear mechanical force or motion
Hydraulic cylinder extend and retract a piston rod to provide a
pull or push force to drive the external load along a straight path
6. TYPES OF HYDRAULIC
CYLINDERS
Hydraulic cylinder are of following types:
• Single-acting cylinders
• Double-acting cylinders
• Telescopic cylinders
• Tandem cylinders
9. SINGLE ACTING CYLINDER
• It consist of piston inside a cylindrical housing called as
barrel
• On one end is attached a rod, which can reciprocate
• At the opposite end, there is a port for the entrance and
exit of the oil
• They produce force only in one direction by hydraulic
pressure acting on the piston
• The return of the spring is not done hydraulically, it is
either done by gravity or spring.
10. DOUBLE ACTING CYLINDER
There are two types of double acting cylinder:
• Double acting cylinders with piston rod on one side
• Double acting cylinders with piston rod on both side
12. DOUBLE ACTING CYLINDER
DOUBLE ACTING CYLINDER WITH PISTON ROD ON ONE
SIDE
• To extend the cylinder, the pump flow is sent to the blank-
end port as shown in fig.
• The fluid from the rod end port returns to the reservoir
• Now to retract the cylinder, the pump flow is sent to the
rod end port and the fluid from the blank end port returns
to the tank as shown in another fig.
14. DOUBLE ACTING CYLINDER
• A double acting cylinder with piston on both sides is a
cylinder with a rod extending from both the ends
• The application involves in a process where work can be
done by both the ends of the cylinder, thereby making the
cylinder more productive
• Double rod cylinder can withstand higher side loads
because they have an extra bearing on each rod to
withstand the loading.
15. TELESCOPIC CYLINDER
A telescopic cylinder is needed when a long strokelength
and a short retracted length are needed.
The telescopic cylinder extends in stages, each stage
consisting of a sleeve that fits inside the previous stage
One application for this type of cylinder is raising a dumping
truck bed.
Telescopic cylinders are available both in single acting and
double acting models.
17. TELESCOPIC CYLINDER
Construction:
• They generally consist a nest of tubes and operate on the
displacement principle
• The tubes are supported by bearing rings, the innermost set
of which have grooves or channels to allow the fluid flow
• The front bearing assembly on each section includes seals
and wiper rings
• Stop rings limit the movement of each section, thus
preventing the separation
• For a given input flow rate, the speed of operation increases
in steps as each successive section reaches the end of its
stroke. Similarly, for a specific pressure, the load shifting
capacity decreases for each of the successive section
19. TANDEM CYLINDER
• A tandem cylinder is used in application where a large
amount of force is required to be applied from a small
diameter cylinder
• Pressure is applied to both the pistons, resulting in a
increased force because of a large area.
• The only drawback is that this cylinders must be longer
than a standard cylinder to achieve an
because the flow must go to both
equal speed
the pistons
simultaneously.
23. CUSHIONING OF CYLINDERS
• For prevention of shock due to stopping loads at the end
of piston stroke, cushion devices are used.
• Cushion may be applied at either end or both the ends
• They operate on the principle that as the cylinder piston
approaches the end of the stroke, an exhaust fluid is
forced to go through an adjustable needle valve that is set
to control the escaping fluid at the given rate.
• This allows the deceleration characteristic to be adjusted
for different loads
• When the cylinder piston is actuated, the fluid enters the
cylinder port and flows through a little check valve so that
the entire piston area can be utilized to produce forces
and motion.
26. CUSHIONING PRESSURE
• During deceleration, extremely high pressure may be
developed within a cylinder cushion.
• The action of the cushioning device is to set up a back
pressure to decelerate the load.
27. MAXIMUM SPEEDS IN
CUSHIONED CYLINDERS
The maximum speed of the cushion rod is limited by the rate
of fluid flow into and out of the cylinder and the ability of the
cylinder to withstand the impact forces that occurs when the
piston motion is arrested by the cylinder end plate.
• For uncushioned cylinder: 8 m/min
• For cushioned cylinder : 12 m/min
• For high speed or externally cushioned cylinders: 30
m/min
28. ACCELERATION &
DECELERATION OF CYLINDER
LOADS
Cylinders are subject to acceleration and deceleration during
their operation. Cylinders are decelerated to provide
cushioning and cylinders are accelerated to reduce cycle
time of the operation.
Acceleration Equation:
v u at
v2
u 2
2as
s ut
1
at2
2
29. QUESTIONS
• Explain the classification of hydraulic actuators.
• Explain various types of hydraulic cylinders.
• Describe the construction and working of double-acting cylinders.
• Derive an expression for force, velocity and power for hydraulic
cylinders.
• Explain the importance of cylinder cushioning.
• Explain various types of cylinder mountings used in fluid power.
• Evaluate the performance of hydraulic systems using cylinders.