CHA PTE R 15 HYDRAU LIC PUMPS Fig ure 15-1 Pump ca tegories COPYRIGHT (2 001 ) EA T ON CO RPORA TI ONC P u m p F a m i l y T r e e P u m p s G e a r V a n e A x i a l B e n t - A x i s V a r i a b l e V a r i a b l e V a r i a b l e V a r i a b l e I n - L i n e F i x e d F i x e d F i x e d F i x e d F i x e d R a d i a l P o s i t i v e D i s p l a c e m e n t P i s t o n N o n - P o s i t i v e D i s p l a c e m e n t ( C e n t r i f u g a l ) Inlet Outlet F ig u r e 1 5- 2 N o n - P o s it iv e D is p la c e m e n t P u m p C OP Y R IGHT (20 01 ) E A T ON C OR P OR A TIO NC Atm os phe ric Pre ssu re In let Ph ase Ou tp ut P has e In let Ou tle t to circ uit to circ uit Atm os phe ric Pre ssu re In let Ou tle t Fig ure 15 -3 P osi tive d is pla ce me nt p um p COPY RIGHT ( 2001 ) EA T ON CORP ORA T IONC Atmospheric Pres sure Inlet Phase Inlet Outlet to circuit C OP YRI GH T (200 1) EA T ON C OR POR A TIONC Figure 15-4 Aerated fluid caused by inlet air leak Ou tp ut P ha se Atmo sp her ic Pre ssu re In let Ou tle t Hig h ve loc ity microje t f or ma tion Figu re 1 5- 5 Pre ssu rizin g th e flu id co llap se s t he b ubb les C OP Y R IGH T (2 00 1 ) E A T ON C O R P OR A TIO NC Figure 1 5-6 Piston pump valve p late e rosion cause d by ae ration or ca vit at ion CO PY RIG HT (2 00 1) E A T O N CO RP O RA T IO NC Atmos pheric Pressur e Inlet Phase Inlet Outl et to ci rcuit Figure 15-7 Cavit ati on bubbles f ormed by a re stri cted i nlet C OPYR IGH T (20 01 ) E A T ON C OR POR A TIONC Causes of Cavi t ation Causes of Aerati on 1. C logged or restri cted straine r 2. H igh flui d viscosity 3. Lo w fl uid tempe rature 4. Cl og ge d re ser voir b re at he r 5. P ump inlet line too small 6. P ump too f ar above res ervoir 7. P ump too f ar f rom r eservoir 8. E xcess ive pu mp R PM 9. T oo many bends in pump inl et line 10. Coll ap sed hose on pump inlet li ne 1 1. R estricti on on pump inlet li ne 12. Failur e of superc harge pump 1. Lo w r eservoir flui d level 2. D efective pump shaf t seal 3. R eturn l ine above fl uid level 4. I mproper baf fling in the r eservoir 5. Lo ose fitt ing on pum p inlet line 6. D efective seal on pump inl et line 7. I ncorrect r eservoir design 8. P orous hose on pump inl et line Ca use s of C avi t atio n an d Ae rati on Figure 15- 8 C auses of aeration and cavit ation C O PY R IGH T ( 20 0 1) EA T O N C O R PO R A TIO NC Inlet Outlet Idler Gea r Driven Gear V olume on this side increas es as g ear teeth u nmes h V olume on this side dec rease s as gear teeth m esh Figure 15-9 Externa l gear pump COP Y RIGHT (200 1) EA T ON CORPORA TIONC In let Ou tle t E xte rn al G ea r Cr e sc e nt Se a l In ter na l Ge ar V olu me o n th is sid e inc re a se s a s ge ar te eth u nm es h V olu me o n th is sid e d ec re a se s as g e ar te eth m es h Fig ur e 15 -1 0 C re sc en t se a l typ e in ter na l ge a r p um p C O P Y R IGH T (2 00 1) E A T ON C O R P O R A TIO NC I n le t O u t le t G e r o t o r I n t e r n a l G e a r V o lu m e o n t h is s id e in c r e a s e s a s g e a r t e e t h u n m e s h V o lu m e o n t h is s id e d e c r e a s e s a s g e a r t e e t h m e s h F ig u r e 15- 11 Ge r o t o r T y p e I n t e r n a l G e a r P u m p COPYR IGHT ( 20 01) E A T ON CO RPORA TIONC Rotor V ane Cam Ri ng Figure 15-12 B asic pu mping e lement s of a vane pum p C OP YRI GH T (200 1) E A T ON CO RPO RA TIO NC Inc re as in g V ol u me Inl et sid e De cr ea s in g V ol u me O u tle t sid e F ig ur e 1 5- 13 E cce nt rici ty be twe en r oto r an d ca m r in g COP YRIGHT (20 01) EA T ON CO RPO R A TIO NC In le t R ot or R o t o r R o t a t i o n V ane C am O ut le t F ig ur e 15 -1 4 R ot at in g gr ou p w it h in le t a nd out le t po rt s C OPYR IGHT (20 0 1) E A T ON C ORP ORA TIO NC Inlet Outlet Rot ati on Figur e 1 5-15 Balan ced vane pump design C OP Y R IGH T (2 00 1) E A T ON C OR P OR A TIO NC F ig ur e 1 5- 16 In te rch a ng ea bl e c am rin gs pr ov id e a s e lec tio n o f fl ow s CO PY RI G HT (2 001) EA T O N CO RP O RA T IO NC Ca m R in g thr ow Ri ng th ick ne s s InletInlet Ou tletOu tlet Rot at ionRot at ion Fig ure 15 -17 Ro t ating the ca m ring 18 0 reverse s the direction of rot at ion COPY R IGHT (20 01 ) E A T ON CO RP ORA TIO NC S ha f t S ea l V a ne In le t O u tle t P re s s ur e P la te R oto r N ote : C am R in g R in g/ Ro to r/ V an e as se m bl y s ho w n in r ed F ig u re 1 5- 18 F ix ed d is pl ac em en t 搒 quare pump? COP Y RIGH T (20 01) E A T ON C ORP ORA TIO NC I n l e t Q u a d r a n t O u t l e t Q u a d r a n t Pre ssure bala nce acro ss vane Reduce d van e tip load ing in the inlet qu adra nt V ane Intra- vane Figure 15-19 V ane and intra-van e assembly COPY RIGHT ( 2 001) E A T ON CORPORA TIONC Rotor Surface Pressure Act s On These Areas Pump Outle t Pressure Act s On This Area Base of sl ot in rotor Figure 1 5-20 Outlet pressure in the i ntra-vane a rea assu res va ne-cam c ont act COP YRIGHT ( 2001) EA T ON CO RPORA TIO NC Out let Inle t Rot ation Equ alizing holes Intra- vane f eed n otch. Feed notch trails the direc tion of rot atio n Figure 15-2 1 Po rting in rotor and s ide pla tes pro vide s vane pressu re balanc e CO P Y RIG HT (200 1) E A T ON COR P ORA TIO NC Figure 15-22 Hig h performa nce pump cartridge component s COP YRI GHT (20 01) EA T ON CORPOR A T I ONC Support plate Support plateCam Ring V aneIntra-V ane Locating Pin gpm Figure 15-23 Intra-van e pump cart rid ge ass embly COP YRIGHT (2001 ) E A T ON CO RPORA TIO NC Figure 15-2 4 Intr a-v ane pump cartr idge inst alled C OP YR I GH T (2 00 1) EA T O N C O RP O RA T IO NC Fig ure 1 5-25 I ntra -van e p ump asse mbl y CO PY RI GH T ( 20 0 1) EA T O N CO R POR A TIONC S haf t S eal Out let Cam R ing Out let S upp ort P late Rot or In let Su pp ort P late In tra -van e V an e In let Fig ur e 15 -2 6 A d ou bl e pu mp w ith a s ing le in let CO PYR IG HT (2 00 1) E A T O N CO R PO RA T IO NC D ou ble P um p Fig ure 15-27 A double (t andem) pump wi th sep arate i nlet s CO PYRIGHT (200 1) EA T ON CORPOR A TIONC T andem Pu mp s Inlet Pump 2 Inlet Pump 1 Outlet Pump 2 Outlet Pump1 Figur e 15-28 The piston pump co ncept COPYRI GHT (2001 ) EA T ON CO RPO R A T IONC from reser voir piston area 1 in 2 str oke 2.32 in . to circ uit flyw heel RPM A pum ps di splacem ent is the amou nt of f luid d ischar ged per rev olution o f the inp ut s haf t. Disp lacem ent is usua lly meas ured in in /rev (s omet imes abreviat ed C IR or C ID) 3 F i g u r e 1 5 . 2 9 A R a d i a l P i s t o n P u m p Figure 15-30 Pintle porting in a radial piston pump COPYRIGHT (2001) EA T ON CORPORA TIONC Pintle Cylinder block Shoe retractor ring Cross key coupling Piston Reaction ring Figure 15-31 A ben t-axis piston pump COPY RIGHT (2001) EA T ON CORPORA TIO NC Case Drain Inlet Rot ation Outl et Case Dra in Rot at ion Outl et In let Swas h Plat e Cylinder B lock Pi sto n Pre -L oad S pring S phe rica l W a sher Sh oe Retrac to r P late Figure 15- 32 An in-li ne piston pump COP YR IGHT (200 1) E A T ON COR PORA TIO NC Figure 15- 33 Compone nt s of an i n- line pi ston pump C OP YRI GH T (20 01 ) EA T ON C OR POR A TIO NC Cylinder Block Pre-L oad S pring Load Pins S pherical W asher Shoe Retra ctor Plate Pistons Swash Plate Case Shaf t Seal Bearing Shaf t V alve Plate Figure 15-34 Metering losses i n a fixed displacem ent system CO P Y R I G HT (2 0 01 ) E A T ON CO RP O RA TIONC Operating Pressure - p si Pump Output Flow gpm Pump Displac ement Relief Setting Cor ner Hor sepower (Pri me Mover Requirement) Metering Point Useable Power W asted P ower F i g u r e 1 5 - 3 5 V a r i a b l e D i s p l a c e m e n t V a n e P u m p COP YRIGHT (20 01) E A T ON CO R P ORA TIO NC T imi ng ad just m ent fo r no ise re du ct ion O utl et Por t Inl et Po rt M ax imu m V olu m e Ad just m ent Pre ss ur e Co m pen sa to r F i g u r e 1 5 - 3 6 V a r i a b l e d i s p l a c e m e n t r a d i a l p i s t o n p u m p COP YRIGHT (200 1) EA T ON CORPO RA TIONC Outlet Port Inlet Port Cylinder B lock Control J ournal Maximum V olume Adjust ment Slipper Piston Displac ement Control S troke R ing Ret aining Ring Fig ure 15 -37 V ari abl e d is pla cem ent be nt a xis pis ton pu mp C O PYR I G H T (20 01 ) EA T O N CO R PO R A TIO NC Di spl ace me nt Co ntr ol Inle t P ort Ou tlet P ort P ist on Ca se Dr ain Dr ive Sh af t Fla ng e Ro t ati on Dr ive Sh af t P ist on Ro d V alv e P late Cy lin der B loc k Maximum Displac ement Reduced Di splacement Zero Displacemen t Figure 15- 38 Displacemen t is controlled by the angle of the cylind er block COPY RIGHT (20 01) EA T ON CO RPORA TI ONC Figu re 15 -39 Mec han ical Disp la cem ent C on trol COPYRIGHT (2001) EA T ON COR PORA TIONC Fig ure 1 5-4 0 C ro ss se ctio n o f an in- li ne pis ton p ump COPY R IGHT ( 2001) EA T ON CO RPO RA TIONC Y ok e Sw as hpl ate Y ok e Act uat ing Pis ton Pre ssu re C omp en sa tor Ful l S trok e Figure 15-41 Pump dis placement is based on swash plat e angle COPYRIGHT (20 01 ) E A T ON CORPORA TIO NC S trokeS troke OutletOutletOutlet InletInletInlet S troke Figure 15-42 Compensato rs control the str oke adjus ting piston COP YRIGHT (200 1) E A T ON CORP ORA TI ONC Y oke Y oke Actua ting Piston Pressure Compen sator Compen sating Figur e 1 5-4 3 Pres sure limit ing com pens ator oper ation C OPYR IGHT (20 0 1) EA T ON COR POR A T IONC T o Actua tor Case Drain C i r c u i t S c h e m a t i c Inle t Outle t Case Drain Figure 15-44 Energy saved by pressure compensation COPYRIGHT ( 2 001) E A T ON CO RP ORA T I ONC Operating Pressure - p si Pump Output Flow GPM Compensator Setting Corner Ho rsepower (Prim e Mover Requirement) Metering Point Useab l e Powe r W asted Power V ariable Displacem ent Pum p System Conse rved Power Pump Dis placement Figure 15-45 Pist on pump wi th load sensing and pressure li miting compensa tor CO PY R IGHT (200 1) E A T O N CO RPO R A TIO NC Y oke Actuating Piston Load pr essure from sy stem Figure 15 -46 Lo ad sensing / pr essure limiting co mpens ator oper ation COPY RIGHT (200 1) EA T O N CORPORA TIONC T o Actua tor Case Drain Loa d Sense Signa l Inp ut Inlet Out let Case Drain Circuit Schemat ic F igure 15- 47 Ene rgy sa vings c aus ed b y load s ensing COPYRIGHT (200 1) EA T O N C OR PORA TIO NC O per atin g P res sure - p si Pum p O utpu t F low G PM Pum p D isplace me nt Com pens at or Set tin g Cor ner Ho rsep ower (Pr ime M ov er Requi rem ent) Me ter ing Poi nt Us eable Po wer W as ted Pow er V ariabl e Di splac em ent Pu mp Sy s tem Cons er ved P ower Figu re 15 -48 T orq ue lim iting co mpen sator o per ation COPYRIGHT (20 01) EA T ON CO RPORA TIO NC T o Actu ato r Case Drain F i g u r e 1 5 - 4 9 Y o k e p o s i t i o n s e n s i n g p i s t o n r e t r a c t e d CO PY RI GH T (2001) EA T ON C ORPORA TIONC 1 2 3 Pressure Pump Ou tlet Pressure P Displace ment Sensing Pressure Conne ct to Pump Y oke Pump Case Pressure Location in Bo re Displace ment Sensing Pressure F i g u r e 1 5 - 5 0 Y o k e P o s i t i o n s e n s i n g p i s t o n e x t e n d e d COPYRIGHT (2001 ) E A T ON CO RPOR A TIO NC P re ss ur e P um p Ou tl et P re ss ur e P Di sp lac em ent S ens ing P re s su re Co nne ct t o P um p Y ok e P um p Ca se P re ss ur e Loc at ion in B or e Di sp lac em ent S ens ing P re s su re F i g u r e 1 5 - 5 1 R e d u c e d h o r s e p o w e r r e q u i r e m e n t s b y r e d u c i n g c o r n e r h o r s e p o w e r CO PY RI G HT (2001) EA T ON CORPO RA TIONC Pump Outp ut Flow GPM Pump Displace ment Inpu t T orque Limit ation (Prime Move r Prote ction) Compe nsato r Settin g Meter ing Point Operat ing Pre ssure-p si Usea ble Powe r Cons erved P owe r W asted Power Figure 15-52 Electroh ydrau lic disp lacem ent c ontrol C OP YR IGHT (20 01) EA T ON COR PO R A TIONC Case Drain T o Actuator