Slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. If you continue browsing the site, you agree to the use of cookies on this website. See our User Agreement and Privacy Policy.

Slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. If you continue browsing the site, you agree to the use of cookies on this website. See our Privacy Policy and User Agreement for details.

Successfully reported this slideshow.

Like this presentation? Why not share!

1,084 views

Published on

hydraulic subtopic

No Downloads

Total views

1,084

On SlideShare

0

From Embeds

0

Number of Embeds

2

Shares

0

Downloads

152

Comments

0

Likes

2

No embeds

No notes for slide

- 1. Hydraulic actuators are installed to drive loads by converting the hydraulic power into mechanical power. The hydraulic actuators are classified into 2 category: ◦ Linear actuator - Hydraulic cylinders ◦ Rotary actuator - Hydraulic motors, rotary actuators
- 2. Converts hydraulic energy to mechanical energy. Generates linear movements. Linear motors. Basic types: o Single acting cylinder o Double acting cylinder
- 3. Only piston side is supplied with hydraulic fluid. Only work in one direction. Return stroke effected by spring or load. Applications: ◦ Lifting ◦ Clamping ◦ Moving workpiece
- 4. Single Acting Cylinder A single acting cylinder is only powered in one direction It needs another force to return it such as an external load (e.g. in a car hoist or jack) or a spring. No hydraulic fluid is present on the low pressure side.
- 5. To extend the cylinder or to push the load, pump flow and pressure are sent to the pressure port. When pressure is released, the spring automatically returns the cylinder to the fully retracted position.
- 6. Gravity Return Single Acting Cylinder : In Circuit
- 7. Hydraulic Cylinder : In Application
- 8. Both piston surface is supplied with hydraulic fluids. Fluid power works in both directions (extend & retract) When piston extends, the fluid on rod are displaced in reservoir. When piston retract, fluid in piston area are displaced in reservoir.
- 9. Hydraulic Cylinder : Double Acting Cylinder A double acting cylinder is powered in both direction. In the case of double-acting cylinders, both piston surfaces can be pressurized. Pressure Port and Vent port can be change during extending or retracting.
- 10. Double Acting Cylinder : In Circuit
- 11. Bore diameter o Working pressure determined by bore diameter o Larger diameter produces larger forces Piston rod diameter o Normally 1/6 of bore diameter Stroke length o Length by which the piston rod moves from one extreme position to another extreme position
- 12. Working pressure o Pressure that can be handled by cylinder o Limited by size of bore, rod and tube thickness Test pressure o Pressure used during testing (by manufacturer) o Normally 1.5~2 times of normal working pressure
- 13. Area ratio ϕ = AP/APR ; APR = AP – AST AP : Area of Piston AST : Area of Rod
- 14. Cylinder is selected to suit application load (F = P × A). Can be used to calculate piston diameter. Even so, hydraulic mechanical efficiency must be included, 2 . . . 4 4 . . hm hm hm F p A F d A p F d p
- 15. Standard bore diameter, dp Standard rod diameter, dst 25 32 40 50 60 63 80 100 125 φ dst (mm) 1.25 12 14 18 22 25 28 36 45 56 1.4 14 18 22 28 32 36 45 56 70 1.6 16 20 25 32 36 40 50 63 80 2 18 22 28 36 40 45 56 70 90 2.5 20 25 32 40 45 50 63 80 100
- 16. A cylinder with area ratio 2:1 is to lift 40 kN load. The max system pressure for pump is to be 160 bar. Calculate the piston diameter, dp and piston rod diameter dST for this system. The mechanical-hydraulic efficiency of cylinder amounts is 0.95.
- 17. Piston diameter, dp 24 ; 40,000 ; 160 1600 / . . 33.5 5.79 6 p hm F d F N p bar N cm p cm cm
- 18. Piston rod diameter, dst 2 28.27 2 28.27 4 4.24 4.5 P P PR P ST ST ST A A A A A d d cm
- 19. Hydraulic Cylinder : Extending FE = p x Ap FE AP vE AR Where : Ap = Piston cross section area (m2) Q = Volume flow rate (m3/s) AR= Rod cross section area (m2) vE= extend rod velocity (m/s) FE= Extend force (N) p = pressure from pump (N/m2) p
- 20. Hydraulic Cylinder : Retracting FR = p x (AP-AR) AP AR vR FR Where : Ap = Piston cross section are (m2) Q = Volume flow rate (m3/s) AR= Rod cross section area (m2) vR= Retract rod velocity (m/s) FR= Retract force (N) p = pressure from pump (N/m2) p
- 21. Convert hydraulic energy to rotary mechanical energy Motor capacity: 3 ( ) ( ) ( ) ( / min) ( ) M p V Q n V p pressure Pa M torque Nm V Geometricdisplacement capacity cm Q Flowrate L n speed rpm
- 22. Example ◦ A motor with capacity of V = 10 cm3 is to operate at a speed of 600 rpm. What flow rate is required by the motor?
- 23. Establish relationship between P1 and P2 (eg. P1 = 9P2 +3F1-5). Show the calculation steps. A1 A2 F1 F2 P1 P2 5cm 1.5cm A1 A2
- 24. Cylinder Force : Examples
- 25. Cylinder Velocity : Examples
- 26. Cylinder Delivery: Examples A Q v 21 vv and

No public clipboards found for this slide

Be the first to comment