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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.
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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.
Types of Hydraulic Motors • Gear Motors • Vane Motors • Piston Motors • Limited Rotation Actuator
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 21300 “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
Efficiency Two factors Internal leakage Volumetric efficiency and speed decrease due to leakage. Internal friction Mechanical efficiency loss due to torque loss Effv= (rpmact/rpmtheo) * 100 Effv= volumetric efficiency Effm= (Tact/Ttheo) * 100 Effm= Mechanical efficiency Effoa=(Effv/100)*(Effm/100)*100 Effoa= Over All Efficiency Performance
The mechanical torque desired must be specified in order to find required working pressure. Pin= (T*2)/Disp. The rpm desired must be specified in order to find required flow rate. Q= (rpm * Disp.)/231 Performance
Power • Hpout= (Tlb-ft * rpm)/5252 • Effoa= (Hpout * 100)/ Hpin
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