HYDRAULIC ACTUATORS.pptx

Hydraulic Actuators: Cylinders – Types and construction, Application, Hydraulic cushioning – Hydraulic motors

1. ME8694 HYDRAULICS AND PNEUMATICS UNIT-2 HYDRAULIC ACTUATORS

2. Hydraulic Actuators Hydraulic systems are used to control and transmit power. A pump driven by a prime mover such as an electric motor creates a flow of fluid, in which the pressure, direction and rate of flow are controlled by valves. Hydraulic actuators are devices used to convert pressure energy of the fluid into mechanical energy

3. Types of hydraulic actuators 1. Linear actuator: For linear actuation (hydraulic cylinders). 2. Rotary actuator: For rotary actuation (hydraulic motor). 3. Semi-rotary actuator: For limited angle of actuation (semi-rotary actuator

4. Types of Hydraulic Cylinders Hydraulic cylinders are of the following types: Single-acting cylinders. Double-acting cylinders. Telescopic cylinders. Tandem cylinders .

5. SINGLE ACTING CYLINDER According to the type of return, single-acting cylinders are classified as follows: Gravity-return single-acting cylinder Spring-return single-acting cylinder

6. Gravity-Return Single-Acting Cylinder

7. Spring-return single-acting cylinder

8. Double-Acting Cylinder Double-Acting Cylinder with a Piston Rod on One Side

9. Double-acting cylinder with a piston rod on both sides

10. Telescopic Cylinder A telescopic cylinder is used when a long stroke length and a short-retracted length are required. The telescopic cylinder extends in stages, each stage consisting of a sleeve that fits inside the previous stage.

11. TANDEM CYLINDER It is used in applications where a large amount of force is required from a small-diameter cylinder.

12. 2005/2006 I. Hydraulic and Pneumatic Systems 12 Rotary hydraulic actuators Swivel vane rotary actuator: Limited angle in both directions Maximum angle always smaller than 360° The same torque in both directions Piston rotary actuator: With rack and gear coupling Here maximum angle may be larger than 360° Mindkét irányban azonosan működő hengerrel és fogasléces meghajtással működtetett tolódugattyús lengőhajtás Párhuzamdugattyús lengőhajtás Forgódugattyús lengőhajtás menettel működtetett meghajtócsappal Limited angle rotary actuator Limited angle rotary actuator Parallel piston rotary actuator ??? ???

13. 2005/2006 I. Hydraulic and Pneumatic Systems 13 Rotary hydraulic actuators Parallel piston rotary actuator

14. 2005/2006 I. Hydraulic and Pneumatic Systems 14 Rotary hydraulic actuators ???

15. 2005/2006 I. Hydraulic and Pneumatic Systems 15 Rotary hydraulic actuators Rack-and-pinion piston-type rotary actuator:

16. 2005/2006 I. Hydraulic and Pneumatic Systems 16 Semi-Rotary hydraulic actuators Limited angle rotary actuator:

17. 2005/2006 I. Hydraulic and Pneumatic Systems 17 Semi-Rotary hydraulic actuators Limited angle rotary actuator:

18. 2005/2006 I. Hydraulic and Pneumatic Systems 18 Semi-Rotary hydraulic actuators Helix actuator:

19. Cushioning of cylinders : A hard impact of the piston at the end surfaces has to be inhibited – kinetic energy has to be absorbed. This is done by increasing the hydraulic resistance at the end of the stroke.