2 1 9 4 8 t 2 2 8 Un'i'ted States.,Patent Office, P @ a t e n t e d A u g . 9 , 1 9 6 0 @ 15948,228 GEAR ARRANGEMENT, FUNCTIONING A@' . - . - I 1. ' 5 PUMP OR MOTO]K Xtirt Gustav Ahlen, Stockl@olm, . Swedeny assignor to Svenska Rotor Maskiner Aktieb6lag, N:icka, Sweden, a corporation of Sweden Ffled Apr. 17,195.6, ger. Tio. $.78,8a6. 7 CIaims. (Cl. 1036-120) This invention relates. to an arrangem@ent futc@tionin 15 9 as. pump or motor, which -consists olf a iear and, a follower,gear meshing with, each othei- Arid viotki@,.i- ift a casing provided with inlet and outlet for aTi oper;tiiig d medium. Actually the iiivention refer& to a eston ac@ 20 cording to which the mesh of the teeth of the gears )may be varied-. The most characteristic feature (yf"t@@ irlvention is -@i Sbaft (the a -astment shgft) ro ing iii fhe t4t pj:q7 vided with an eceetitrip bearing surface fo@. t@-e , i@-iati 25 ,ge@r locaied on said surface so that bY rotating thd ad_ i @tment- shaft in the c th, : spacing of'. th-@6 -t e - geA s ma-y be varied- while mailitaininj@ A seal b&tweefi th@, oute@r pe,riphe@ry of ',the follower izea:r and the casitir. Thii t'@ ie feeth of the gears@ alway@ ipps@ 'wi@th a miniinup@ of- plqy 30 '15,6iween t'nem. Pteviously:it has been propoged' to il@sigti go4T pli4.11@s itianner that the nitittial m-esti betw-eeh the teeth feedin-, the operating ii@ediurii in y b6, v@iri@ Iii 6'@n@e n @ @i@ll,,n thp: q@aftg, of tlie 4r@r,, ar'f-,,s@ip.ppit6d gp . 135 1 indevendentlv of each: othe e F, ach oilp iii. a, sop iatat6- @ait c@s@s,, @vh-ereas the casing ig dividi,-d iiito t-Wo -@alvQ@ variable as to the shaft spacing. Tho, Pait@ witk th eir gp@ar beariiigs @Lre rri , ov'ed bv nieans &f',adipstin screws g iii relation t each oiher, thii.s making i@t - pp'ssi@lp, t6, -@,ar y 40 th gear mesh. Thi8 airan g@,nien.t is. n6t 8@@tisfactory, tiom a seali g point of- viow afid 4@an not, be. @st@d diiii@g ro,.adi Q,P,pr tion. In anothe kn6wn dosijzn the'fb!16,,6r-gbar, i@,@in@eited g . e, ap, 6ecentticallv into a disr, resemblih :th sh - e Of'@,ct6scc]@t 4,5 e ich can,bp- rotated froni the rotatihgih; disc it is, possible to var th pja@, betwe@c@nth . y- e C@ gear- t,eetb-. Tfi rough such variatio-n of the play it wds- ]@osgible to, rc@ adjust the, pprnp-cap, ity, w@e@@n@ t,h'e,liaria'tion in-- caoacft-@ io a, great extent would fto@n Icakage, d4et@@ th-- 50 fact, that the fpllower geat ig lacking p roper s uppor,i. -71@i@ design i8 in the first Place iiitendqd, f6r.,the adiustrnent of. nlinimum -pl4v betnveen, th ' @ar@, .-@The-,deg@eq 9c pf the play will vary with thQ @ec e nd the@i,@"@p c 'lioi0ity, a Play wiU 55 volumetric- efficieiicy will vary with@ the, play. @an's c.also- between, th e follower gear and, the @ inper, wA of the disc functionin,- as, a guide@, for- I whicb re@ason this design in tic first place is inteiTd@,@d i only-- to - improve the mesh to compensate for wesx.@ Ifi additio n.-th6@'design is diffic.ult, to manufacture as - weH - @-s@expezisive, 60 Designs of gear punips -of variable@ capaoity: kiftow-ii@ u-1) @to,,,now have bedn Iiinited td th6.@e provided with -ears -of the, exteriial toothtype-, bdt as. will - b@-- evid,-ht, ftotft the following descriptioii@ 6f @om6 alternatives of the iii65 ven-idn; this can :also be applied' tQ advantoge in- designing gear pumps and, motor of the inter@Eil@ t(O@h.. t@ie rOsi@e@tiv6ly. a,,Aliiigs a nu-nber s in:th@.- acco-int)anying d.r Qfdaigii.@.of the invention,are shown- ohly as exa @,s, Witb oAt - cording to the invention with gears of the external tooth type. 'Fig. 2 sho@ys, a pergpective view of the arrangement according to Fig@ I with one end of the casing removed showin the gears in full mesh. 9 Fig. 3 shows a perspective view similar to that in Fig. 2 with, t-he gears removed from each other. Fia 4 shows srhematically the profile of the intemal outliiie of the wall @art,of the casing which surrounds, thef follower gear. Fig. 5 shows ia dross@section taken alon- the line 5-5 in Pig. 6 through another arrangement according to the ijivefition with the drive gear of internal tooth type and the follover gear installed inside the foriner when the g@ ful ly in mesh with each other. ears are -Fig. 6 shows a vertical I section according to the li,ne 6-6 in Fig. 5@. Fig. 7 shows,A sertion along the line 7-7 in Fig. 5. ows ail Fig. 8 sh @a radial det ' section alon-g the direction ilidic@ied by the line 8. in Fig' 5. 9 - s h o w s a n e n d v i e w t a k e n , i n t h e d i r e c t i o n i n d i - cated, b the line 9 in Fi' . 6 y 9 Fig- 10, shows a crosgrsection sirnilar to that in Fig. 5 wiih the gears removed a maximum distance from each othet. P' I I lbows iri perspective viiew pardy brbken away Ig. sj filrther@ modification of an arrangement with internal gpeir as iii Figs. 5-10 but *ith pierced tooth- bases in the ext,ernal gear race of internal tooth type. Fig. tZ sh6ws , a cros @s-section through the last-mentionod atteingement.. Figg.- 13, and 14 8how further modified desi2n details inclii&ed in the invention, Fig. 1-5 shows a diagram of,the ptessure rise as @i fuilct@on of the RPM. of the arrangement -according to, the invend,on operating as a pump. Fi @ 1,6 shows schematically a, control system, for the Eittangeftient fitstly operati-ng as a pump (full-draw-n m Y 70.follower.gearZ2. Th etooth@addendums-pl an ftither limitati6n. 20, cQntact,-,the, inner surface 40 of tITe casing-halfrI stio,,vs a perspective Aew of an 4rrangement ac_ coitarting said,addendums without play as muc@has pos@ I,ines),, secondly as a motor (qashed lines). 1,7 shows schem@ttically the @rra-@igement, equipped 9'. th,,.a ccintrol stem in connect@ion with the, application wi Sy bf the,,.ar@rarigement. as a, pump, by means of which control sy@teiii- the prcssure regulating, range of the pum-p ,illovis ar-i6d-. 'ts6lf to be v @Pig IS shoos chematically a. control syste-tn Of modified' design, when7 the arrangement is- applied. as, a motor.. sh m IC -Fig. @ 19 - ows sche at @ ally, ari additional modified @ design. of, @- control avstein when the: arran g@ment is appliect as, a, pump. The arrangement 8hown in Pigs. 1-4 consist& of two g6ars-20,@ 22 of external tooth ty-pe loc@ated side by side-in a rasing 24. which is provided with ducts 26,. 28- for ir,,Iet and- biitlet, of. the., operating medium, The axle -shaft of th dri e ve gear . 20, is, indicated @y, 30. The follower gear 22 is. located. on, a bearingsurface 34,, which, is@ ewentric m r&lation to an adjustment shaft for tlus gear. T-he ..bearing.surf-ace,is,locatedonsaid@shaft. The-adjustment shaft. 32 is@upported in the casing: extending through one end-3.6@ of@ the:same by means of ajournat 33. By means of this journal. 38 the adjustment shaft 32, will actnate either. by, the @applicati6n of positive force- or by adjustment agairist a spring.@ force. Due to the eccentric support qf fl@e foflower gear.:22 a displaceinent-. of the r6tating center of the follower gear, 22@ is@ obtained@ by rotatin-, the adjustment shaft 3Z along an are, in such@ a manner that. tWs gear 'm one-limit@ stop.- is: in fuH@ me@h with the drive gear 20, and in the other li mit-. stbp-is 6nlY mesh@ suticiently to maintain constant@ iotation 6f @- thb -of, the drivo@ gear

sible @vhereas the inner sur@face 44 of the other casing 46 surrounding ihe follower gear 22 is generated in the following manner. Referring -to Fig. 4, 48 constitutes the center of the adjustment sb@aft 32 and the rotation center 50 of the fohower gear 22, which is movable along an are with the radius r from one extreme limiting position 50, in wbich the gears are in maximlim mesh giving maximum capacity, to a second extreme limiting position 50' in which the gears are in minimum mesh giving minimum vap@ac,@tY. Accordingly the iadjustment sbaft 32 wil-I revolve about its center 48 within the angle of radii 48-52 ar.d 48-52', and the,enveloping surface 44 comprises three cylindrical iareas 54-52, 52-52' and 52---56. The first cylindrical area 54-52 has a radius slightly grcater than the radius R of said fo'Jower gear and a center of curvature coinciding with -the center 50 of the follower gear 22 when in its extreme limiting position for maximutn mesh. The portion 54-52 extench'ng from the high pressure por-t has a length corresponding to at least the space width between two teeth of the follower gea:.-. The second cylindrical area 52-52' has a radius equal to the sum of the radius R of the forower gear, the width r of the eccentricity of the bearing surface in relation to the adjustment shaft and the necessary clearance between the gear iand the stirface. The por-tion 52-52' has its center of curvature r-oinciding with the center 48 of the adjustment shaft 32. The portions 54-52 and 52-52' merge into each other at the point 52 lying in the radial plane from the center 48 of the adjustment shaft through the center 50 of the follower gear in its extreme litniting position for maxiinum mesh. The cylindrical area 52'-56 has a radius slightly greater than the radius R of the follower gear and a center of curvature coincid'ing with the center 50' of the follower gear 22 when in .its extreme limiting position for minimum mesh. The portions 52-52' and 52'-56 merge into each other at the point 52' lying in the radial plane f@rom the center 48 'of the @adjustment shaft through the center 50' of the follower gear in its extreme limiting position for minimum me-sh. Figs. 2 and 3 show the follower gear 22 contacting th,e first land tlurd cylindrical are@a portions of the enveloping surface 44 respectively. By varying the mesh variable volumetric capacity is effected with constant r.p.m. Rotation of the adjustment shaft 32 can be accomplished by means of a lever 58 and adjustments can be made by the application of positive force or by self-4adjustment against a spring 60. Through @a resilient actuation of the adjustment shaft a consta@nt pressure is created after the pump, when it is possible to vary its capacity by applying various degrees of tension to the spring. The constant pressure is maintained in the area which is covered by the variation that is possible between t-he two limit stops. The pump maintains a cer-@ tain pressure irrespective of the resistance in @a certain area for the quantity varia@tions allowed by the puinp. .The same variation can be achieved also by manual or comparable adjustment of the shaft when the pressure can be made to vary depending on the ability of the receiving collector tank to absorb fluid quantity at a cettain pressure. In the @arrangement according to Fig. I it is possible to use the lever 58 for the adjustment of the forower gear within two stops limited by stop devices 62 and the resil'ient arrangement 60 for taking up the torque by means of which the adjustment shaft is artuated by the oil pressure. In the form described in Figs. 1-4 the tooth profile is the involute type, which provides perfect mesh irrespegtive of the shaft spacing as long as sufficient quantity of teeth a-re meshing. In the above type the gears are further designed with helical teeth. In such helical gears i,t is possible to select the design in such a way that looking in the axial direction the front end of a followmg tooth profile is equal with the rear end of the preceding @tooth profile. D-ae to the helical gears animprovement is made by the f@act that the teeth of the two gears always are in effective mesh with each other. In Fig. 2 the direction of the gear rotation has been marked with arrows, just like the direction of the liquid flow when the arrangement is used as a pump. When used as a motor the flow direction of the medium is reversed. The same remark applies to the other illustrated designs. With an arrangement according to the design used as a motoi constant torque is obtained within 10 a certain r.p.m. range. In the arrangement according to Figs.@ 5-10 the drive gear 64 is of intemal tooth type with unpiereed tooth bases 66 and encased in the cavity created by the casing composed..of the halves 70, 72. The gear race of the 15 drive gear 64 may be designed in one piece with a supporting part 74, to which the axle shaft 76 of drive gear 64 is connected, which axle shaft is supported in casing half 70. The follower gear 78 eccentrically supported is located inside the drive gear and its adjustiiient shaft 80 20 with eccentric bearing surface 82 for the forower gear is supported in casing half 72, where 84 indicates a bearing bushing. The adjustment shaft 80 is provided with an extemal lever 86 operating between the stops 88, 88' and the rotation of the adjustment shaft towards the extreme 25 limit stop corresponding to stop 89' occurs against the actuation of a spring 90. To the adjustment shaft 80 a circular disc 92, concentric with said shaft, is attached which is supported in the casing half 72, i.e. on the opposite side of the gear ele30 ments in relation to the supporting part 74 for the extemal gear element 64. This disc 92 has on the high pressure side of the artangement a sealing strip 94 projecting axially down into the intermediate space which contacts the tooth addendum circle of the intemal gear 78. A sta35 tionary sealing strip 96 is attached to the casing half 72 and located in said intermediate space. The latter sealing strip 96 contacts extemally the tooth addendum circle of the drive gear 64 and internally the outer edge of the sealing strip 94 contacting the follower gear 78, when the 40 sliding plane 98 between these two sealing strips is located along a circle concentric to the adjustment shaft 80, the diameter of which is equal to that of the disc 92. The intemal sealing strip 94 accordingly follows the adjustment shaft 80 when it is adjusted rotationally and 45 sfides along the sealing surface 98 against the extemal stationary sealing strip. Figs. 5 and 10 show by way of comparison the reciprocal positions of the adjustable parts in fuH mesh of the gears and in the extreme limit stop, corresponding to maximum separation of the gears from 50 each other, respectively. For safety sake at least one of the sealing strips is provided with a packing 100 facing the joint between the sealing strips. The disc 92 on the adjustment shaft 80 is provided with curved :ftow holes 102, 104 for the axial inlet and outlet 55 106, 108 of the operating medium of the pump (the designations inlet and outlet change place when the arrangement is used as a motor). At the rear of the supporting part 74 for the extemal gear race 64 a cavity 110 is located axially behind the flow hole 104 on the pressure 00 side of the arrangement and connected by means of ducts 112, 114, 116 with this flow hole in order to equalize the surface pressures (Figs. 7-8). In this as well as in all other designs according to the invention the pressure component of the hydrauec pres65 sure on the -pressure side, actuating the driven gear or the driven gear and the sealing strip, should always pass through the distortion center of the eccentric -shaft on the side that provides a torquedisengaging the gears. The bearing pressure resulting from the driven gear should al70 ways tend to rotate the eccentric @shaft in such a way that the mesh of the gears will decrease when the arrangement is operating as a pump and the reverse when the arrangement is operating as a motor. Ile arrangement shown in Figs. 11-12 is principally 75 of similar design as that described above in connection

W" Figs. 5-10 differing from said arrangement only by the fact that fhe tooth baseg of the extdrhal gear element 118 @ird pierced so that radial inet and outlet hole@ '120 -are @-,fibdted ior: the operating medium. For this teq@s6n 'the @.miiig 122 of the arrangement should be 'p'rovided with tLt 5 16Mt in prineiple radial inlet-s 124 land outlets 126 for the 6pdkb,tiiik medium. Otherwise- the detail corre .06!lding *ith th& parts of Figs. 5-10 are designated with the SgLme fdereiftdb chdtacters and in order to @ avoid repetitiot: any fuither destription of the same ig not 'necessary. The 10 ELxle@shAft 6f the dn've gear 118 is suppor-ted by mdans df iieedl'e be@itings 128 in a bushing 130 drranged oti the corr6sponditfg end of the casing- 122. A pre@sut6 meditiiii atiuated operating mechanisni 132'is pro@ided for the @he6hanical operation of the lever 86 @against the Actij15 ati6ii of ihe 81iring 90. Figs.:13@ ghd 14 show the gear profiles of extemal and inteinal gear type with cut dowii tooth qddenduing 134 gfid 13'6,@ regpectively, @with the exception in this iiis tail to df the e'nd peirts 138 -and 140, ri@spectively, of the tooth 20 addendiimg, which function as mesh: Vides for@'the cdrotatiolft,of @th'e gears. At least one of the gear's' iri ea(@h Offd i)f ihe @rtangements described above can be provide-d with such a design due to which the arrangement has to be made larger in order to obtai,n desired capacity, but 25 by means of which an increasing degree of variation is obtained with regard to the capacity of the arrangement, etc. In order to be able to get down to zero in regard to circulating quantitysuch an outlet is to be used. In the diagram of Fig. 15 the pressure rise is shown 30 as the function of the r.p.m. (n) of the puml@ when the curve constitutes the volumetric efficiency of the pump. The regulating range of the pump is indicated by means of a thick line, provided it works with a spring only for self-adjustment of the adjustment shaft against 35 the effect of the liquid pressure in the pump discharge. By adding a servomotor, for example an electrically Operated solenoid, hydraulically or pneumatically operated pressure plunger or similar power source, it is possible to apply a torque to the adjustment shaft. The size and 40 direction of this torque may be optionally - adjustable, whereby the various pressure regulating range curves are obtained, which are included in the diagram shown in Fig. 15. Accordingly above the curve for the sp@-Ing alone are curves where the servo motor torque is added 45 to the spring and below said curve characteristics in wh@ch the servo motor counterbalances the spring effect. The servo motor power and the spring power may be located either partially with each other as in Fig. 11 or located in series, whereby various types of characteristics are ob- 50 tained. In the regulating system according to Fig. 16 the arrangement is shown functioning as a pump -by means of fall-drawn lines. The lever 142 for adjustment of the adjustment shaft 144 for the eccentric bearing surface 55 is retained by a spring 146 so that the gears are in maximum mesh. The pump discharge is connected with a pressur e plunger 150 by means of a line 148. At rising pressure in the discharge the gears are accordingly separated from each other. 60 Thus it is possible to adjust the pump irrespective of @ the r.p.m. or rp.m. variations and resistance variations within a certain range in order to provide constant pressure and the possibility of obtaining optional l@ressure. Principally constant pressure is obtained in certain areas 65 and it is possible to select the pressure range from outside without having to by-pass any liquid quantity. Whenthe same arrangement is used as a motor, which is indicated -by dash lines, thespring IL46' works instead to separate the gears from each other, whereas the inlet 70 of the motor is connected with the pressute plunger 150 via the line 148' in such a manner that -the @.pressure plunger 150 will tend to increase the mesh between the gears. In the control system according to Fig. 17 with the, 75 arr4ngement @4pplied as: a pump its di-,rh4rg@p may 'hecoirnected- eithler behind the pressure plunger @50 via hne 149 or in f-ront of the pressure plungpr 150 via the line 148' when the change-over is made via a threewa-Y valv@ 152. T-his meas that in the diagram shown in Fig. 15 the curve scales ascend and doscend, respectively,, in relation to the base line for remote conttol only@ A pressute variatOT 154 c@an @be installed in the supply line to the pressure plunger 150 and for operating medium'in the pregsure pltmg r a se, lum in e parate med' T elation to the pump idperatin m ediu ni ay possibly 9 ., m be us@ed. @ 'fbe,servo inotor may bodesigned -to be 4ct4a@ted from a distance by ineans for variation <)f the 1)ressure ijft @the 4upply line to the pressurb plunger, Fig, 18 shows @a control.,system for a motor corre. sponding to the -system in Fig. 17 for a pump. The spring 146' tends @to separate -the gears f@rom each other, whereas the motor inlet iby means of a line 148' is connett6d With the Dressureplunger in -sueh a manner that on rising pressure the gears assume:a niore close fit. -The -c6ntrol system in Fig. @9@ for iati. arrangemen-t according to @tbe inveiition operatingas a pump is provided With a @servo motor in the form of a solenoid, the armature 156 -of which is actuated by the coil 158. The coil 158 is fed from the circuit .160 and by means of a current changer it is possi-ble to altemate the direction of the current and further control the amperage by means of a regulating resistor !164 for @the purpose of moving the regulating range of the pumpiaccording -to the principles as shown in Fig. 15. What I