2005/2006 I. Hydraulic and Pneumatic Systems1 Hydraulic actuators: cylinders Cylinder types: Single acting: work can be done only in one direction Piston Double acting piston: Piston rod on both sides Plunger Work is done in both directions Telescopic Fast moving Tandem Fast moving

2005/2006 I. Hydraulic and Pneumatic Systems2 Hydraulic cylinders Hydraulic cylinder Hidraulikus munkahengerek Rögzítőpálcás kivitel 1. Rögzítőpálcás hidraulika henger, a hengerfejen található karimás rögzítéssel

2005/2006 I. Hydraulic and Pneumatic Systems3 Hydraulic cylinders Hydraulic cylinder Hidraulikus munkahengerek Hengeres kivitel 1. Hengeres építési móddal készült hidraulika henger

2005/2006 I. Hydraulic and Pneumatic Systems4 Hydraulic cylinders Properties: The cylinders have to be good quality steel with close tolerances. There have to be good sealing both at the piston rod and at the cylinder. With time dirt may come in and damage the surfaces. This has to be possibly reduced. In this case, the leakage will increase all the time.

2005/2006 I. Hydraulic and Pneumatic Systems5 Hydraulic cylinders Calculation of cylinders friction forcesinertial forcesmaximum load slow motion, can be often neglected Backward: Outward: Q A2A2 A1A1 p1p1 p2p2 vBvB v0v0

2005/2006 I. Hydraulic and Pneumatic Systems6 Hydraulic cylinders Calculation of cylinders Hydraulic cylinders should be possibly operated in the 3 rd region for smooth operation. If the cylinder is new, the leakage losses are negligibly small so that: η c = η mech FfFf 1 v 23 1.Stick-slip 2.Transition 3.Normal behaviour ηcηc ΔpΔp outwards inwards at higher pressures

2005/2006 I. Hydraulic and Pneumatic Systems7 Hydraulic cylinders Checking for buckling n: safety factor: 1-3,5 l k : buckling length I 1 : moment of inertia of the piston rod E: elasticity modulus of the rod material Maximum permissible force:

2005/2006 I. Hydraulic and Pneumatic Systems8 Hydraulic cylinders 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.

2005/2006 I. Hydraulic and Pneumatic Systems9 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 Párhuzamdu gattyús lengőhajtás Forgódugattyús lengőhajtás menettel működtetett meghajtócsappal Limited angle rotary actuator Parallel piston rotary actuator ???

2005/2006 I. Hydraulic and Pneumatic Systems10 Big pictures End of normal presentation Beginning of big pictures

2005/2006 I. Hydraulic and Pneumatic Systems11 Hydraulic cylinders Cylinder types: plunger smaller force, better efficiency, axial support is necessary but cylinder does not have to be so good quality Without inner buffer With inner buffer (pilot piston)

2005/2006 I. Hydraulic and Pneumatic Systems12 Hydraulic cylinders Cylinder types: piston, single acting, pressing-cylinder Spring inside outside

2005/2006 I. Hydraulic and Pneumatic Systems13 Hydraulic cylinders Cylinder types: piston, single acting, puller Spring inside outside

2005/2006 I. Hydraulic and Pneumatic Systems14 Hydraulic cylinders Cylinder types: piston, double acting Velocity is different

2005/2006 I. Hydraulic and Pneumatic Systems15 Hydraulic cylinders Cylinder types: piston, double acting Piston rod on both side Velocity is the same in both directions

2005/2006 I. Hydraulic and Pneumatic Systems16 Hydraulic cylinders Cylinder types: piston, double acting Piston rod on both side Velocity is different in the two directions depending on cross section ratio of the rods

2005/2006 I. Hydraulic and Pneumatic Systems17 Hydraulic cylinders Cylinder types: double acting piston, tandem

2005/2006 I. Hydraulic and Pneumatic Systems18 Hydraulic cylinders Cylinder types: single acting, fast moving

2005/2006 I. Hydraulic and Pneumatic Systems19 Hydraulic cylinders Cylinder types: double acting, fast moving

2005/2006 I. Hydraulic and Pneumatic Systems20 Hydraulic cylinders Cylinder types: telescopic, single acting Large working paths or limited space

2005/2006 I. Hydraulic and Pneumatic Systems21 Hydraulic cylinders Cylinder types: telescopic, double acting Large working paths or limited space

2005/2006 I. Hydraulic and Pneumatic Systems22 Hydraulic cylinders Checking for buckling: Euler’s cases Picture Free buckling length Manner of end fixing Note 1. Case One end free One end fixed Or trunnion at end mounting style 2. Case Two ends pivoted and guided 3. Case One end guided and pivoted, other end fixed 4. Case Two ends fixed and guided mounting style

2005/2006 I. Hydraulic and Pneumatic Systems23 Hydraulic cylinders Cushioning of cylinders: 1.Piston 2.Cushion nose 3.Cylinder cap 4.Stroke volume 5.Cushion orifice 6.Throttle 7.Cushion adjustment screw 8.Mother 9.Non-return valve 10.Gas valve

2005/2006 I. Hydraulic and Pneumatic Systems24 Rotary hydraulic actuators Parallel piston rotary actuator

2005/2006 I. Hydraulic and Pneumatic Systems25 Rotary hydraulic actuators ???

2005/2006 I. Hydraulic and Pneumatic Systems26 Rotary hydraulic actuators Rack-and-pinion piston-type rotary actuator:

2005/2006 I. Hydraulic and Pneumatic Systems27 Rotary hydraulic actuators Limited angle rotary actuator:

2005/2006 I. Hydraulic and Pneumatic Systems28 Rotary hydraulic actuators Limited angle rotary actuator:

2005/2006 I. Hydraulic and Pneumatic Systems29 Rotary hydraulic actuators Helix actuator: