Systems ME 597/ABE 591 - Lecture 15 Dr. Monika Ivantysynova MAHA Professor Fluid Power Systems MAHA Fluid Power Research Center Purdue University
Hydrostatic transmissions - Hydrostatic transmission basic principle - Hydrostatic transmission circuit solutions with additional functions - Advanced transmission concepts - Power Split drive technology 2 2
Hydrostatic transmission Basic Circuit Design 3
Hydrostatic transmission Two variable units controlled in sequence M torque P power V displacement 4
Hydrostatic transmission Two variable units simultaneously controlled 5
Hydrostatic transmission Pump control manually, with mechanical feedback 6
Hydrostatic transmission Pressure limiter Engine 7
Hydrostatic transmission Automotive control Engine 8
Hydrostatic transmission With electrohydraulic controlled displacement units 9
Example Wheel loader Lifting/Tilting Steering 17.4:1 1:1 or 1.4:1 10 17.4:1
Wheel loader Transmission Design Example Design the hydrostatic transmission for a given wheel loader and calculate the traction force- speed characteristic for the entire speed range. The following parameters and requirements are given: Engine speed: 2200 rpm Engine power: 90 kw Vehicle mass: 10 t Bucket volume: 1 m 3 Density soil: 2kg/dm 3 Dynamic roll radius: 0.617 m Coefficient of rolling resistance (soil): 0.08 Coefficient of rolling resistance (asphalt): 0.015 Max vehicle speed (on road): 40 km/h Max traction force: 25 kn 11
Axial piston machines Selected pump and motor sizes Max. Displacement Volume Max. Speed Max. Pressure (contin.) Max. Pressure Theoretical flow rate @1000 rpm Power @ 100 bar, 1000 rpm Displacement charge pump Mass variable pump Torque @ 350 bar Fixed displ. motor Mass fixed displ motor Displacement Volume ß=7 Max. Speed @ ß=7 Mass variable motor 12
Trends & New Requirements High traction force & high max. speed Continuously variable transmission (CVT) Reduction of fuel consumption Cost effective 25 mph and more 100,0 kn and more F Z v e v max v 13
Transmissions - today Power Shift Gearbox with hydro dynamic torque converter state of the art solution complex, multi-stage gear system high number of clutches low starting efficiency interrupted power flow K1 K2 C/E 14
Multiple SICFP 05, June Motor 1-3, 2005, Concept Linköping Zero-adjustable Hydraulic Motor F, β β VM β Pump I II III v unlock 15
Power Split Drive SICFP 05, June 1-3, 2005, Linköping Basic structure Ring wheel Satellite carrier Sun wheel additive mode recirculating mode 16
Planetary Gear SICFP 05, June 1-3, 2005, Linköping Three wheel planetary gear train Willis equation: When satellite carrier B is block n B = 0 Negative planetary gear, the standing gear ratio i 0AC is negative 17
Planetary Gear SICFP 05, June 1-3, 2005, Linköping negative standing gear ratio i 0AC Speed of individual wheels: Directions of rotation of sun wheel A and ring wheel C are different, when the satellite carrier B is blocked! 18
Power Split Drive Output coupled System SICFP 05, June 1-3, 2005, Linköping Fendt, Germany, developed a transmission system for agricultural tractors, which is in series production since 1996 19
Power Split Drive SICFP 05, June 1-3, 2005, Linköping Input coupled System Sundstrand Corporation - Responder transmission New development by John Deere 20
PSDD SICFP 05, toolbox June 1-3, 2005, for Linköping Simulink POLYMOD allows Precise Loss Models 21 V I n I M I I II n II M II Best Efficiency? P IN n IN n C n A V II n OUT P OUT M IN M C M A M OUT POLYMOD Model Losses M S Losses M S Loss Behaviour Pump & Motor Q S = f(vi, n, Δp) ν = const. 21 M S = f(vi, n, Δp) ν = const.
Power Split Drive System Example SICFP 05, June 1-3, 2005, Linköping 22 Development by Claas