Vickers Servo Valves - Eaton

1 651 Released 12/93 flows to 57 l/min (15 USgpm) Pressures to 210 bar (3000 psi)SM4-10/12/15 ServovalvesVickers Servo Valves Vickers , Incorporated 1993 All Rights ReservedIntroductionVickers SM4-10/12/15 servovalves canprovide system closed loop control withexact positional accuracy, repeatablevelocity profiles, and predictable force ortorque applications include plasticinjection molding and blow moldingsystems, test and simulationequipment, die casting machines,hydraulic press brakes, animation andentertainment equipment, oil explorationvehicles, and lumber three models in this size of the highperformance SM4 series offer a widerange of rated flows from 3,8 to 57 l/min( to 15 USgpm) at np of 70 bar(1000 psi).The SM4 is a two-stage, modulardesign, flow control valve which can bemanifold or subplate mounted. Asymmetrical, dual coil, quad air gaptorque motor is integrally mounted to thefirst stage nozzle flapper pilot valve withsix screws.

2 The second stage utilizes afour-way sliding spool and sleevearrangement with a mechanical nulladjust. Spool position is fed back to thefirst stage by means of a cantileverspring. An integral 35 micron (absolute)filter protects against contamination ofthe pilot SM4 servovalve, used with ahydraulic cylinder, position transducer,and appropriate electronics, can provideinfinite cylinder position control to within0,025 mm ( in) or better (dependingon component selection, length of stroke,and load characteristics).When applied with Servo hydraulicmotors, tachometers, and appropriateelectronics, the SM4 provides infiniteproportional flow control for real-timevelocity/acceleration profiles that can beclosed loop error corrected to withinone-tenth of a revolution per appropriate pressure transducersor load cells, cylinders, and electronicsin force control applications, the SM4offers exact load pressure /force controland excellent system stability withpressure and load to 1% full field-proven design of theSM4-10/12/15 servovalves, combinedwith Vickers precision manufacturingtechniques.

3 Provides you with theoptimum in system and BenefitsDThe wide range of SM4 flowcapabilities allows selection of thevalve size best suited for high strength aluminum alloy ofthe second stage valve body meanslighter weight with rugged symmetrical, dual-coil, quad airgap, dry torque motor in Vickersservovalves, with its extremely fastresponse to input signals, can producehighly accurate control frequency response available on request providesenhanced system bandwidth forcritical performance integral 35 micron (absolute) filterprovides extra first stagecontamination spool and sleeve are hardenedstainless steel to minimize wear anderosion. The O-ring mounted sleeveeliminates spool binding and ensuressmooth spool lap and sleeveporting are available to provide thespecific flow control required forspecial SM4 s symmetrical designprovides inherently dependablemetering of control flow with minimumnull shifts.

4 The result is moreconsistent machine * seals are flexibility of standardized portcircles, mounting patterns, andadapter manifolds makes Vickersservovalves a cost-effective choice forreplacing existing servovalves andenhancing existing SM4 features a simple interface toan available dual filter module thatprovides extra protection against Valves are available that cangreatly reduce initial systemcontamination levels prior to SM4installation.* Viton is a registered trademark of theDuPont Data3.. Performance Curves7.. Model Code10.. Installation Dimensions11.. SM4M(E) Mounting Subplates12.. SM4A Adapter Manifolds15.. SM4FV Flushing Valves20.. Weights ..21 Additional Accessories21.. Application Data22.. Cross Section of TypicalSM4-15 Servovalve3 Operating DataFlow and LeakageAll data is typical, based on actual testsat 70 bar (1000 psi) p, 30 cST (141 SUS), and 49 C (120 F).

5 Model SeriesMaximum RatedFlow 10%l/min (USgpm)Maximum TotalNull Leakagel/min (USgpm)Maximum Pilot Flow at70 bar (1000 psi) pl/min (USgpm)SM4-1038 (10)14(037)SM4-1245 (12)1,4 ( )0,35 ( )SM4-1557 (15)2,0 ( ),( )PerformanceMaximum Supply Pressurebar (psi)210 (3000)Minimum Supply Pressurebar (psi)14 (200)Proof pressure % maximum supply pressureAt Supply Port: 150At Return Port: 100 Burst pressure , Return Port Open% maximum supply pressure250 Maximum Operating Temperature C ( F)135 (275)Hysteresis Around Null% of rated current 3 Symmetry Error% of rated current<10 Linearity Error% of rated current<10 Threshold% of rated current Test ResultsVibration Test5 Hz to 2000 Hz along each axisNo damage to componentsShock TestUp to 150g along all axesNo damage to componentsEndurance TestTo ISO 6404No degradation in performance4 Flow GainNormal region for standard modelsshown with typical no-load flow gaintolerances excluding hysteresis.

6 100 100% RATED CURRENT% RATED FLOW 80 60 40 200+20+40+60+80+100 80 60 40 200+20+40+60+80+100"5%Flow tolerance "10% 10 100% INPUT CURRENT% MAXIMUM SUPPLY pressure 80 60 40 200+20+40+60+80+100 8 6 4 20+2+4+6+8+10To 100% ratedPressure GainChange in load pressure drop with inputcurrent shown with no valve flow andclosed control gain in the null region is >30%of supply pressure per 1% of nominal gain50% nominal gain5 Change in Rated FlowRated flows at valve pressure drops from5 bar (70 psi) to 210 bar (3000 psi) forseven of the available (70)1,1 ( )00 POWER TRANSMISSION EFFICIENCY % TransmissionEfficiencyMaximum power envelope expressed asa percentage with T port pressure equalto 0 transferred to the load is optimumwhen valve pressure drop is one third ofsupply pressure . Load pressure dropshould be limited to 2/3 of supplypressure so the flow gain of theservovalve remains high enough tomaintain control of the load.

7 Overallhydraulic efficiency must be consideredwhen sizing system heat pressure DROP (P A)+(B T) bar (psi)7(100)14(200)21(300)35(500)70(1000) 140(2000)210(3000)NO-LOAD FLOW RATE l/min (USgpm)2 ( )2,6 ( )4 (1)8 (2)11 (3)15 (4)19 (5)27 (7)30 (8)38 (10)57 (15)76 (20)95 (25)114 (30)RATIOLOAD pressure DROPSUPPLY (15) 57(10) 38(5) 19( ) 9(1) 3,8 VALVE RATED SPOOL l/min (USgpm)135 (35)151 (40)( ) 28(12) 45 Electrical Polarity forControl Flow Out of B PortSingle:A+, B orC+, D Series:A+, D Connect B and C+ Parallel:A+, C+B ,D Connect A and CConnect B and DDifferential:A ,D B+, C+Connect B and CBC , current BA>CDBC+, current CD>BA +ABCD+ + +ABCDABCDABCDS ervovalveServovalveServovalveServovalve6 Coil ResistanceSelect coil resistance and connectionsfor compatible interface to servoelectronics. Recommended coilresistance is shown in bold ResistanceRated Current mANominal ResistancePer Coil at 21 C (70 F)OhmsSingle, Parallel, orDifferential ConnectionSeries Connection20200100 Standard coil3010050tandard coilresistance selection80402020020108050251404020 Optional tional coilresistance selection30030151000105150084 Calculating Frequency Responseat System PressurePS= System pressurePM= maximum supply pressure ofvalve: 210 bar (3000 psi) forSM4-10/12/15fPM= Frequency (at 90 phase angle) atmaximum supply pressure (PM)fPS= Frequency (at 90 phase angle) atsystem pressure (PS)1.

8 Calculate the ratio of systempressure to maximum supplypressure:2. Use the result of step 1 and thecurve below to estimate3. Use the applicable frequencyresponse curve from the followingpages to estimate fPM (the maximumsupply pressure frequency responseat 90 phase angle) for the desiredvalve rated Multiply the values obtained in steps2 and 3. The result is fPS (systempressure frequency response at 90 phase angle).Frequency ResponseFrequency response is defined as therelationship of no-load control flow toinput current with a sinusoidal currentsweep at constant amplitude over arange of frequencies. It is expressed infrequency (Hz), amplitude ratio (dB),and phase angle (degrees). Vickers SM4 torque motors aremagnetically stabilized for reliableservovalve performance at operatingpressures from 14 to 210 bar (200 to3000 psi).

9 As shown in the sample curve (belowleft), standard comparison points forservovalve frequency response arethose frequencies at which 3 dBamplitude ratio and 90 phase : An SM4-15 valve with a flowof 38 l/min (10 USgpm) is to be used at165 bar (2400 psi).1. Calculate the ratio of systempressure to maximum supplypressure:2. Use the result of step 1 and thecurve below right to estimate3. Use the frequency response curvefrom page 8 to estimate Multiply the values obtained in steps2 and 3. The result is fPS (systempressure frequency response at 90 phase angle). (system pressure )PM(maximum supply pressure )fPSfPMPhase lag(shift)7102030 40 5070 1000 5 10 FREQUENCY HzAMPLITUDE RATIO dBPHASE ANGLE degrees12090 15 20200 300 400 5001008070605040302010110 3dB comparison +2400 psi3000 psi+ + +95 HzfPS+ 95 Hz+88 Hz7 Performance Curves3102030 40 5070 1000 5 10 FREQUENCY HzAMPLITUDE RATIO dB 15 20 25 30 35 PHASE LAG degrees901008070605040302010 40% rated current 100% rated current20045 7SM4-1547 l/min ( USgpm)57 l/min (15 USgpm)07102030 40 5070 1000 5 10 AMPLITUDE RATIO dBPHASE LAG degrees12090 15 20 25 30200 300 400 5001008070605040302010110 FREQUENCY HzSM4-10/12/1538 l/min (10 USgpm)SM4-10/12/153,8 l/min ( USgpm)9 l/min ( USgpm)19 l/min ( USgpm)28 l/min ( USgpm)

10 40% rated current 100% rated current6102030 40 5070 1000 5 10 AMPLITUDE RATIO dBPHASE LAG degrees11080 15 20200300 40090706050403020100100 FREQUENCY HzTypical FrequencyResponse CurvesAt 210 bar (3000 psi) 40% rated current 100% rated current88 Step ResponseStep response is defined as the typicalrise time needed to achieve a givenpercentage of control flow time is the time needed fortransient flow fluctuations to diminish towithin a given accuracy range. Both areexpressed in milliseconds (ms).The example at right shows the stepresponse curves for a critically dampedvalve and an underdamped valve. Risetimes are illustrated for 63% of controlflow output, and settling times areshown at 100 5% of control flow timesat 63% flow010200 TIME msOUTPUT FLOW %10020406080 Settling timesto 5% accuracyCritically damped valveUnderdamped valve515120 Typical Step Response Curves forStandard ModelsSM4-10/12/15 shown at 210 bar (3000psi).