ENERGY CONVERSION IN A FLUID POWER SYSTEM. Preview GRC. mechanical friction. File name GA: FLOW GENERATING GROUP. traen_eng GRC: CONTROL GROUP

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1 PRIME MOVER (electric motor, IC engine) ENERGY CONVERSION IN FLUID POWER SYSTEM P P mech mech (exended) P P (useful) hydr hydr rotary shaft G M, Q, Q, M, F, v P W GRC P W GU oil ies oil ies rotary shafts, translating rods P W LOD P W WSTED POWER (heat flo rate) fluid leakages mechanical friction ressure dros overall system efficiency QULITTIVE PPROCH: FUNCTIONL NLYSIS QUNTITTIVE PPROCH: NUMERICL MODELS Q: volumetric flo rate (L/min) : gauge ressure (bar) - = 0 --> atmosheric ressure M: torque (Nm) : angular seed (rad/s) / n (rev/min) F: force (N) v: linear seed (m/s) G: FLOW GENERTING GROUP traen_eng GRC: CONTROL GROUP GU: USERS GROUP Dec 07 7 Rerint 08

2 G - GRC - GU suly line (high ressure) control signal manual electric hydraulic mechanical GU GRC directional control valve, manual oerated G - um return line (lo ressure) valves: - to revent / allo fluid flo - to direct selectively fluid - to limit / reduce a ressure - to control a flo rate (actuator seed) -... (converts shaft seed into a volumetric flo rate by dislacing traed volumes of fluid) - reservoir ( = 0) - filter & heat exchanger -... Q - linear actuators - hydraulic motors (convert volumetric flo rate into shaft angular seed or rod linear seed)... and hat about the fluid ressure? um In synthesis alication for rinting cylinder ositioning v, F, M ONLY IF a flo rate meets resistance a ressure is induced motor G_GRC_GU_eng 09 Nov 05 8 Rerint 08

3 THE LNGUGE OF FLUID POWER International Standard ISO 9/-9 (latest version 9/-0) grahic reresentation of the model of a fluid oer comonent or system YES NO function manufacturing oeration dimensions connections installation GENERL RULES: comonents are created using the basic symbols, taking into account the rules given for their creation symbols sho the rest osition of a comonent all orts (external connections) of a symbol must be shon basic symbols can be rotated (ith increments of 90 ) or mirrored to create comonents comonents must be reresented in the same scale (relative size must be reserved) normintr0_eng 0 Feb 08 9 Rerint 08

4 um M, FUNCTIONL NLYSIS: lant schematic according to ISO-9 G P T GRC GU F,v hydraulic motor (to directions of flo) M, rime mover (electric motor) D4/3 unidirectional restrictor drain line: return to the reservoir the fluid lost due to the internal clearances double acting linear actuator reservoir heat exchanger ressure relief valve filter ilot line (transfers ressure information) in regulating condition Equations for um and hydraulic motor (ideal) * dislacement sring exerting a closing force Fsr that can be modified by the user S surface on hich the inlet ressure acts scstart_eng 0 Feb 08 0 Rerint 08

5 FUNCTIONL NLYSIS: lant schematic according to ISO-9 four-ort three-osition direction control valve closed centre, solenoid actuated, sring centered osition at rest (no command) P T GRC GU F,v P T d D a v x F D = iston diameter d = rod diameter free flo (ideally = ) equilibrium on the iston (steady-state) restricted flo ( > ) restriction of the flo area: the degree of throttling is decided by the user the ingoing volume of fluid er unit time (Q) must be equal to the increment er unit time of the chamber volume (incomressible fluid) valid also for the outlet side: scstart_eng3 09 Feb 08 Rerint 08

6 DUL STGE PRESSURE RELIEF VLVE (FLUID CONTROL 30) SPOOL TYPE - CRTRIDGE CONSTRUCTION S * S FUNCTIONL RESTRICTOR S T P SPOOL (MIN STGE) LL POPPET (PILOT STGE) f sr DYNMIC RESTRICTOR S INTERNL DRIN fca30_eng 5 Nov Rerint 08

7 PROPORTIONL PRESSURE RELIEF VLVE (Denison R4VP) solenoid roortional ilot stage main stage X P T G LVDT mechanical ilot stage (safety) G * X Y fm * S Y limro_eng 08 Jan Rerint 08

8 SIMULTION OF DUL STGE RELIEF VLVE S * = 45 bar PUMP FLOW RTE = 50 L/min D sool = 0 mm f sr = 30 N diameter S = mm S restrictor (load) S S * f sr simvl 08 Jan Rerint 08

9 SIMULTION OF DUL STGE RELIEF VLVE FORCES ON THE MIN STGE * ilot stage f sr / S = 3.8 bar * ilot stage * main stage = 5.5 bar max ressure = 5.4 bar simvl 8 Jan Rerint 08 main stage *

10 CONTROL OF OVERRUNNING LODS WITH "COUNTERLNCE" VLVES overrunning load resistant load F v J a VSH J J3 J4 v F RV * STUDY HYPOTHESES osition D (outard stroke) ---> flo through VC resistant and overrunning loads equations to determine the ressures and actuator equilibrium VC equilibrium resistant load NR F sr (* ) VC VC VC S S F sr NR3 overrunning load J7 J8 J5 DCV J6 Remarks: leak tight conditions attained through oet design. Sools are not leak roof! y-ass centre of DCV to avoid surious ilot signals RV is necessary to limit the ressure at the actuator outlet J9 GQF (*) NR J0 gumdevcb_eng 08 Jan 08 9 Rerint 08

11 STEDY STTE CHRCTERISTIC -F ND v-f WITH VC v F DVC in D resistant load v F overrunning v resistant Q/ out out osition D RV regulates in overrunning * * a * VC resistant v>0 in v=0 NR3 closed v<0 * a *a osition D Q/a * * F * VC overrunning load F overr. * a * a - * VC * VC resist. * * F VC closed VC regulates decreasing flo area VC oen RV regulates resistant load vcbfvf_ne_eng 08 Jan 08 9 Rerint 08

12 VC VLVE (Integrated Hydraulics 60 CPD300) integral NR valve X X Y CTUTOR X (cross ilot line) DIRECTION CONTROL VLVE Y vcb_cbd30 9 Jul Rerint 08

13 PLNT WITH CONTROL OF OVERRUNNING LOD THROUGH VC VLVES Kg F non return valve behaviour X * Note: valves reresented in configuration D RV 0 VC behaviour X Y D0: load blocked D: load loering (overrunning load) D: load lifting (resistant load) guvcbsez_eng GQF (*) 08 Jan Rerint 08

14 TEST RIG FOR OVERCENTRE VLVES (LOD TEST RIG) OVC under test Primary circuit (hydraulic inch) Flyheel Secondary circuit (load) modcar_eng 4 Nov Rerint 08

15 SIMPLIFIED HYDRULIC SCHEME Primary circuit Secondary circuit OVC * br M M VL * VL * OVC s S 0 D SE NR LOD TEST RIG P T Y PV3 decides the flo rate through the rimary circuit VL and NR decide the ressure resectively in the high and lo ressure lines of the secondary circuit D selects the tye of load 0 VP 40 LS PV 3 VP 0 MS Notice that: VM = VM PV3 is mounted on the LS test rig The flo generation unit is located donstairs Qmax PV 3 < Q VP 0 modcarb_eng 4 Nov Rerint 08

16 Primary circuit DETILED SCHEME Secondary circuit Q 3 Q T Q * br NR3 VL NR3 * br brake M M * VL SC brake M OVC NR3 NR3 OVC * OVC s St 0 * OVC s St S D S NR Q 4 SE LOD TEST RIG NR NR Q 4 SE P T Y LS test rig 3 3 VP0 quick coulings mounting of the OVC ith integral shuttle valve 0 PV 3 G LS P P (VP 0) T modcarico_eng 9 May Rerint 08

17 COMPLETE LYOUT OVC valve test rig PV 3 joystick Load Sensing test rig Flo generating unit (donstairs) Data acquisition system modcaricoall_eng 4 Nov Rerint 08