Fluid Power Control

Module:03 ~ Hydraulic SYSTEM COMPONENTS FLUID POWER Module:03 ~ Hydraulic SYSTEM COMPONENTS Sources of Hydraulic Power Construction and working of pumps – Variable displacement pumps Actuators: Hydraulic cylinders, performing linear motion Hydraulic motors, performing continuous rotary motion Hydraulic rotary actuators, performing limited angular Control Components: Direction control valve Flow control valves Electrical control -- solenoid valves. Relays, Accumulators and Intensifiers.

It performs useful work. Hydraulic ACTUATORS FLUID POWER Actuators ENERGY OF FLUID MECHANICAL ENERGY It performs useful work.

Linear actuator: For linear actuation (hydraulic cylinders). Hydraulic ACTUATORS FLUID POWER CLASSIFICATION: Linear actuator: For linear actuation (hydraulic cylinders). 2. Rotary actuator: For rotary actuation (hydraulic motor).

Linear actuator: Hydraulic Cylinders Barrel Base / Cap Head Hydraulic ACTUATORS FLUID POWER Linear actuator: Hydraulic Cylinders TERMINOLOGY: Barrel Base / Cap Head Piston / Rod Seal Gland Tie Rod Ports ROD END BLANK END TYPES: Single-acting cylinders. Double-acting cylinders.

Retraction is done either by gravity or by a spring. Hydraulic ACTUATORS FLUID POWER Linear actuator: Hydraulic Cylinders ~ single acting Graphic Symbol implies how a component operates / functions without showing any of its constructional details. It facilitates circuit analysis. It helps in trouble-shooting. Retraction is done either by gravity or by a spring.

It makes cylinder more productive. Hydraulic ACTUATORS FLUID POWER Linear actuator: Hydraulic Cylinders ~ double acting TYPES: Piston rod on one side Piston rod on both side. It makes cylinder more productive.

Cylinder Cushion Hydraulic ACTUATORS FLUID POWER Cylinder Cushion To prevent shock due to stopping loads at the end of the piston stroke. When the cylinder piston is actuated, the fluid enters the cylinder port and flows through the little check valve. At the end of retraction stroke, an exhaust fluid is forced to go through an adjustable needle valve that is set to control the escaping fluid at a given rate.

Cylinder Cushion :: Graphical Representation Hydraulic ACTUATORS FLUID POWER Cylinder Cushion :: Graphical Representation

Cylinder Force, & Velocity Hydraulic ACTUATORS FLUID POWER Cylinder Force, & Velocity Extension Stroke: VELOCITY FORCE

Cylinder Force, & Velocity Hydraulic ACTUATORS FLUID POWER Cylinder Force, & Velocity Retraction Stroke: VELOCITY FORCE ret ret

Hydraulic ACTUATORS FLUID POWER … and Power

Hydraulic ACTUATORS FLUID POWER Exercise: 01 A cylinder is required to move a 10 kN load 150 mm in 0.5 s. What is the output power? What cylinder size is required to achieve the above speed in a system with a flow rate of 60 LPM? Answer: 3 kW, 65 mm

Hydraulic ACTUATORS FLUID POWER Exercise: 02 An 8 cm diameter hydraulic cylinder has a 4 cm diameter rod. If the cylinder receives flow at 100 LPM and 12 MPa, find the (a) extension and retraction speeds and (b) extension and retraction load carrying capacities. Answer: 0.3315 m/s , 0.442 m/s , 60.32 kN, 45.24 kN

Hydraulic ACTUATORS FLUID POWER Exercise: 03 A cylinder with a bore of 150 mm and a piston rod diameter of 105 mm, has to extend with a speed of 7 m/s, pressure applied is 150 bar. Calculate (a) The flow rate in LPS of oil to extend the cylinder (b) The flow rate in LPS from annulus side to extend the cylinder. (c) The retract speed in m/s using (a). (d) The flow rate from full bore end on retract. Answer: 123.69 LPS, 63 LPS, 13.728m/s, 65.87 LPS

Vertical Piston-Cylinder to lift a load: Hydraulic ACTUATORS FLUID POWER Hydraulic Cylinder carrying a load: Vertical Piston-Cylinder to lift a load:

Horizontal Piston-Cylinder to displace a load: Hydraulic ACTUATORS FLUID POWER Hydraulic Cylinder carrying a load: Horizontal Piston-Cylinder to displace a load:

Inclined Piston-Cylinder to displace a load: Hydraulic ACTUATORS FLUID POWER Hydraulic Cylinder carrying a load: Inclined Piston-Cylinder to displace a load:

Hydraulic Cylinder carrying a load: Hydraulic ACTUATORS FLUID POWER Hydraulic Cylinder carrying a load: Exercise: 04 A 6000 N weight is to be lifted upward in a vertical direction for the system shown in Figure. Find the cylinder force required to (a) Move the weight at a constant velocity of 1.75 m/s. (b) Accelerate the weight from zero velocity to 1.75 m/s in 0.5 s.

Hydraulic Cylinder carrying a load: Hydraulic ACTUATORS FLUID POWER Hydraulic Cylinder carrying a load: Exercise: 05 A 10000 N weight is to be lowered by a vertical cylinder as shown in the figure. The cylinder has a 75 mm diameter piston and 50 mm diameter rod. The weight is to decelerate from 100 m/min to a stop in 0.5 s. Determine the required pressure in the rod end of the cylinder during the deceleration motion.

It permits versatility in anchoring of cylinders. Hydraulic ACTUATORS FLUID POWER Linear actuator: Hydraulic Cylinders ~ mountings It permits versatility in anchoring of cylinders.

Hydraulic Cylinders ~ mountings Hydraulic ACTUATORS FLUID POWER Linear actuator: Hydraulic Cylinders ~ mountings Things which controls the choice of right mountings: The specific application out of the wide varieties. The force applied is tensile or compressive. The bucking load. Alignment of the rod with the resistive load.

Hydraulic Cylinders ~ mountings Hydraulic ACTUATORS FLUID POWER Hydraulic Cylinders ~ mountings Piston Rod Buckling: Euler’s formula states that: L is the free (equivalent) buckling length (cm) depending on – The method of fixing the cylinder and piston rod. The maximum distance between the fixing points, that is, when the cylinder fully extended.

Hydraulic Cylinders ~ mountings Hydraulic ACTUATORS FLUID POWER Linear actuator: Hydraulic Cylinders ~ mountings Types of Mountings: 1. Foot mounting 2. Rod-end flange or front flange mounting 3. Rear flange, back flange or head-end flange mounting Trunnion mounting Clevis Mounting

Hydraulic Cylinders ~ mountings Hydraulic ACTUATORS FLUID POWER Linear actuator: Hydraulic Cylinders ~ mountings Tie Rods The head / cap are connected to the body (barrel) by means of threading, bolts, or tie rod.

Hydraulic Cylinders ~ mountings Hydraulic ACTUATORS FLUID POWER Linear actuator: Hydraulic Cylinders ~ mountings LUGS FLANGES Used when the cylinder is loaded mainly by thrust force (tension or compression)

Hydraulic Cylinders ~ mountings - TRUNNION Hydraulic ACTUATORS FLUID POWER Linear actuator: Hydraulic Cylinders ~ mountings - TRUNNION It  is a cylindrical protrusion used as a mounting and/or pivoting point. It is one part of a rotating join where a shaft (the Trunnion) is inserted into (and turns inside) a full or partial cylinder.

Riverine Lock Gate; Trunnion Mounted Hydraulic Cylinders FLUID POWER Hydraulic ACTUATORS Linear actuator: Hydraulic Cylinders ~ mountings Riverine Lock Gate; Trunnion Mounted Hydraulic Cylinders TRUNNION: It allows angular movement of the cylinder.

It is a fastener system consisting of a clevis, clevis pin & tang. Hydraulic ACTUATORS FLUID POWER Linear actuator: Hydraulic Cylinders ~ mountings - CLEVIS It  is a fastener system consisting of a clevis, clevis pin & tang. The combination of a simple clevis fitted with a pin is commonly called a shackle.

Hydraulic Cylinders ~ mountings - CLEVIS Hydraulic ACTUATORS FLUID POWER Linear actuator: Hydraulic Cylinders ~ mountings - CLEVIS

Hydraulic Cylinders ~ mountings Hydraulic ACTUATORS FLUID POWER Hydraulic Cylinders ~ mountings Piston Rod Buckling: Euler’s formula states that: L is the free (equivalent) buckling length (cm) depending on – The method of fixing the cylinder and piston rod. The maximum distance between the fixing points, that is, when the cylinder fully extended.

Leq = l Leq = 2l Leq = l Leq = l/2 Hydraulic ACTUATORS FLUID POWER Hydraulic Cylinders ~ mountings Piston Rod Buckling: Leq = l Leq = 2l Leq = l Leq = l/2 Center trunnion mounted, Load guided pivoted. Rear pivot and Load guided & pivoted. One end rigidly fixed, free load. One end rigidly fixed, load is guided.

Application of cylinder through mechanical linkage Hydraulic ACTUATORS FLUID POWER Application of cylinder through mechanical linkage

Application of cylinder through mechanical linkage Hydraulic ACTUATORS FLUID POWER Application of cylinder through mechanical linkage First class lever

Application of cylinder through mechanical linkage Hydraulic ACTUATORS FLUID POWER Application of cylinder through mechanical linkage Mechanics of cylinder loading used in first-class lever systems Note 1: If L1> L2, the cylinder force is less than the load force and the cylinder stroke is greater than the load stroke. Note 2: If the inclination of cylinder is less than 10o,its effect can be ignored in equation

Application of cylinder through mechanical linkage Hydraulic ACTUATORS FLUID POWER Application of cylinder through mechanical linkage Second class lever

Hydraulic ACTUATORS Application of cylinder through mechanical linkage FLUID POWER Application of cylinder through mechanical linkage Mechanics of cylinder loading used in second-class lever systems Note 1: Comparison with the first-class lever. Second-class lever requires smaller cylinder force, a smaller size (lesser diameter) cylinder can be used. Note 2: Compared to the first-class lever, the second-class lever also results in a smaller load stroke for a given cylinder stroke.

Application of cylinder through mechanical linkage Hydraulic ACTUATORS FLUID POWER Application of cylinder through mechanical linkage Third class lever

Hydraulic ACTUATORS Application of cylinder through mechanical linkage FLUID POWER Application of cylinder through mechanical linkage Mechanics of cylinder loading used in third-class lever systems Note 1: In a third-class lever system, cylinder force is greater than load force. Note 2: Reason of using this lever system is to produce larger load stroke than cylinder stroke at the expense of a larger cylinder diameter.

Exercise: 06 Hydraulic ACTUATORS FLUID POWER Exercise: 06 For the system given in figure, determine the force required to drive a 1000 N load. Answer: 1250 N

Exercise: 07 Hydraulic ACTUATORS FLUID POWER Exercise: 07 For the crane system, determine the hydraulic cylinder force required to lift a 2000 N load. Answer: 6600 N

Four positive positions with two cylinders Hydraulic ACTUATORS FLUID POWER Application of cylinder through mechanical linkage Four positive positions with two cylinders

Toggle: ..\video\Spring toggle mechanism 8.mp4 Hydraulic ACTUATORS FLUID POWER Application of cylinder through mechanical linkage Toggle: ..\video\Spring toggle mechanism 8.mp4

Rack moving perpendicularly to the cylinder Hydraulic ACTUATORS FLUID POWER Application of cylinder through mechanical linkage Rack moving perpendicularly to the cylinder

Motion transfer to a distant port Hydraulic ACTUATORS FLUID POWER Application of cylinder through mechanical linkage Motion transfer to a distant port

Fast rotary motion using steep screw nut Hydraulic ACTUATORS FLUID POWER Application of cylinder through mechanical linkage Fast rotary motion using steep screw nut

Application of cylinder through mechanical linkage Hydraulic ACTUATORS FLUID POWER Application of cylinder through mechanical linkage A single-sprocket wheel produces rotation in the plane of motion

Application of cylinder through mechanical linkage Hydraulic ACTUATORS FLUID POWER Application of cylinder through mechanical linkage A double-sprocket wheel produces more nearly continuous rotational motion

Application of cylinder through mechanical linkage Hydraulic ACTUATORS FLUID POWER Application of cylinder through mechanical linkage TRAMMEL PLATE