Presentation on theme: "Hydraulic Motors Brought to you by: Demetri Preonas Greg Unverferth."— Presentation transcript:
Hydraulic Motors Brought to you by: Demetri Preonas Greg Unverferth
Overview of Lesson How they work Types of Motors Performance Applications
How a hydraulic motor works High pressure fluid is used to turn a shaft. This is done in many different ways. Much like a cylinder the power comes from the pressure acting over a large area and creating a large force.
Gear Motors External Gear Motor –2 rotating gears, the area of the gear teeth is where the pressure acts to create force –Both gears turn simultaneously –One gear is connected to the output shaft and the other is an idler. Model “B1 Series” Gear Motor Eaton ® Heavy Duty Series 1 Variable Motor
Gear Motors Internal Gear Motors Two categories –Direct drive gerotor, works much like a rotary engine. –Two gears, an inner and an outer. –The pressure pushes them around a center point, turning a shaft
Vane Motors Spring loaded vanes are connected to a rotor The rotor turns inside a cam ring (elliptical hole) The vanes slide in and out of the slots in the rotor to make contact with the cam wall.
Piston Motors Many different types of piston motors All of them use the same basic principles Much like a cylinder, only turns a shaft like the cylinders in your car engine. Generally the most efficient High power, high speed, high pressure
Piston Motors Most efficient Often used in aerospace applications due to high power to weight ratio
In-line Piston Motors Simple construction Low cost Used in low torque high speed applications, such as machine tools
Radial Piston Motors High Torque Low speed Possible application could be a roller.
Bent Axis Piston Motor Is one example of variable displacement motor. The angle is altered to change the displacement.
Limited Rotation Actuator Also sometimes called a oscillator. Has limited movement High torque
Performance Efficiency Two factors Internal leakage –Volumetric efficiency and speed decrease due to leakage. Internal friction –Mechanical efficiency loss due to torque loss Eff v= ( rpm act /rpm theo) * 100 Eff v = volumetric efficiency Eff m = (T act /T theo ) * 100 Eff m = Mechanical efficiency Eff oa =(Eff v /100)*(Eff m /100)*100 Eff oa = Over All Efficiency
Performance The mechanical torque desired must be specified in order to find required working pressure. P in = (T*2 )/Disp. The rpm desired must be specified in order to find required flow rate. Q= (rpm * Disp.)/231
Power Hp out = (T lb-ft * rpm)/5252 Eff oa = ( Hp out * 100)/ Hp in
You just learned: How a hydraulic motor works The basics of the different types of motors Some possible applications for hydraulic motors How to calculate power How to find efficiency