Патент USA US3075482код для вставки
Jan. 29, 1963 _ G. GARNIER - 3,075,472 VARIABLE-FLOW PUMPS oF THE DRUM PIsToN 4TYPE vFiled March 5', 195s ' 5 Sheets-Sheet 1 f7.2 V GEORGES GARNIER BY , _ @4h/@M ATTORNEYS Jan. 29, 1963 ' G. GARNIER 3,075,472 VARIABLE-FLOW PUMPS oF THE DRUM PIs'roN TYPE Filed March 5, 1958 3 Sheets-Sheet 2 6 47 Id j? INVENTOR GEOR GES GARNIER Blvd-„M ha@ ATTORNEYS Jan. 29, 1963 G. GARNIER 3,075,472 vARIABLE~FLow PUMPS oF THE DRUM PIsToN TYPE Filed March 5, 1958 5 Sheets-Sheet 5 ßy my 'u Í jím 3,075,472 ice it Patented Jan. 29, 1963 2 piece with the latter. In a modification, this abutment means is constituted by a balancing piston disposed in 3,075,472 VARIABLE-FLÜW PUMPS GF ThE DRUM PIS'I‘ÜN TYPE Georges Garnier, Asnieres, France., assigner to Air Equipernent, Asnieres, France, a French company Filed Mar. 5, 1958, Ser. No. 739,329 Claims priority, application France Mar. 8, 1957 5 Claims. (Cl. 103-162) ’ a bore in the housing and constantly applied against the rear face of the cam by the delivery pressure in a re gion denn-ed in suit-able manner -for substantially balanc ing the thrust exerted on the cam by the pump pistons. Owing to this fixed abutment member, or to this bal ancing piston, the pivot pin merely maintains the cam in position and is subjected to but a small force. The object of the present invention is to provide im 10 In another improvement, the plate which applies the piston shoes against Ithe forward face of the cam is posi provements in variable-How pumps of the drum piston tively driven in rotation by the rotor so as notably to type i.e. having pistons sliding in bores provided in a reduce friction. This drive could be obtained, on the drum, or rotor, pumps in which the stroke of the pistons one hand, by providing a suitable connecting means, for in the rotor depends on the position of a cam or swash plate tiltable »about an axis orthogonal to the axis of the 15 example of universal joint type, between the support plate for the shoes and the «sliding return member which rotor. is axially disposed in the rotor Iand is subjected to` the One of these improvements concerns the manner of action of Ia spring and, on the other hand, by positively mounting the rotor. It is known that, to obtain correct driving this Iaxial return member through the medium pump operation, it is essential that the rotor remains applied constantly against the distribution surface, the 20 of the roto-r. _ l _ In a particular embodiment of this connectingy means, the latter is formed by a thin member comprising two tribution 'surface creating considerable leakage. lugs disposed in a recess in the support plate for the It has been discovered that, to satisfy this condition, shoes and two lugs disposed in a recess disposed in the the rotor must be carried by at least one main bearing disposed in a Well-defined region in the vicinity of the 25 axial return member orthogonal to the other recess. The positive driving in rotation of the return mem pivot axis of the cam, and that, if other’ bearings are ber may be ensured by la lug forming akey or by a slid provided outside «said region, these bearings must have ing yconnecting between the return member and the end greater play than that of the main bearing or bearings. of the shaft journalled in the auxiliary bearing of the The region in >which the main bearing or bearings are located is determined mathematically by the condition 30 pump body, which has, for example, hat-faced portion and is slidably mounted in an aperture having a corre that the resultant of the forces exerted on the rotor, apart spending shape formed in an axial extension o-f the return for the reaction of the distribution surface be directed member. toward said distribution surface and fall within the sur Another improvement relates to the piston shoes. face of contact of the rotor and the said distribution The spherical head of the piston is generally set in the surface. shoe »and the latter bears on the cam by a hat part. It In a particular embodiment, the rotor is carried by a is very advantageous to reduce the coefficient of fric shaft which extends therethrough and is rigidly fixed slightest gap or separation between the rotor and dis tion ot the shoe on the cam so as to improve the eñiciency to the housing, the bearing, or bearings, being disposed land prolong the life of the pump. in the aforementioned region. For this pur-pose, it has already been proposed notably This arrangement is advantageous in that the pres 40 ence of »the cam plate, the piston shoes yand the support plate, makes it practically impossible to provide a bear ing outside the rotor in the deñned region mentioned hereinbefore. This arrangement also enables the rotor to be driven 45 by a ring gear machined directly on the rotor and mesh to mak-e the cam plate of graphite or to provide elec trolytically a deposit or layer of metal on the shoe hav ing a -goo-d coefficient of friction (cadmium, indium or silver, for example). But these solutions have disad vantages. In the first case, lthe graphite cannot support high mechanical stresses and the cam plate of lgraphite must incorporate a rigid reinforcement, for example of steel. The result is a rather space-consuming structure which is heterogeneous and might be rather fragile. In the second case, the electrolytic coatings on the shoe are thin and it is ditiicult to be sure of their adherence, and numerous diñîculties have arisen due to irregular de ing wit-h a gear rigid with the driving shadtof the pump, since only the arrangement of a central shaft permits providing a rotor bearing in a plane perpendicular to the rotor axis and containing said ring gear. In this case, the invention also provides «an arrange ment whereby the meshing of the rotor ring gear is such posits which ñake oiî. -. that the delivery passageway of the pump is located in According to the invention, the shoes are provided With the plane of the meshing and on the side of the axis of 55 an element comprising at least one ñat face and composed the rotor opposed to that of said meshing. of a metal having a good coetîicient of friction, for ex According to another improvement to the centering of the pump> body or rotor in the housing, there is pro vided, in addition to a main bearing on the pump body ample silver, this elernent being disposed in the shoe in such manner that the flat face protrudes from the shoe and itself, a second bearing carried by the housing and in 60 ensures that the shoe bears against the cam plate only through the medium of this ñat face. This element could which is journalled the cylindrical end of a shaft ñtted be set in the shoe or could be simply maintained in posi in the pump body, for example by a conical portion, tion by the force exerted by the piston yon the cam. and lixed in position by a nut. In a particular embodiment ot said element, the latter Another improvement is in the pivotal mounting of is in the form oi a thin plate lodged in a shallow recess the tiltable cam or swash plate and provides, in addi 65 in the shoe. _ ` tion to the usual pivot pin, abutment means which ex erts on the cam an action balancing the thrust exerted on the cam by the pump pistons, this abutment means being in contact with the cam through the medium of a part-cylindrical face, the axis of the cylinder coinciding In another embodiment, said element protrudes from the shoe not only on the side adjacent the cam but also on the side adjacent the head of the piston and they recess formed in the shoe is such that the spherical head of the 70 piston is retained merely by the edges of the shoe and with the pivot axis of the cam. bears against the inner protruding face of said sliding ele in one embodiment, this abutment means is constituted by lìxed parts rigid with the housing or machined in one ment. ' ‘ ' v3,075,472 4 3 under the `effect of the delivery pressure of the pump pre vailing in the chamber 22 at the rear of the piston. The It can 'be seen that after Wear of the sliding plate or element of the invention, it is easily changed by dis mantling the pump, whereas wear of the electrolytic de forward face of the piston `and the corresponding part 24 of the cam have a part-cylindrical shape, the axis of the posits would require changing the entire shoe, that is, cylinder coinciding with the axis of the pivot pin 20 would require detaching the spherical end of the piston. thereby permitting tilting of the cam. Further features and advantages of the invention will By means of this arrangement, the cam 15 is constantly be apparent from the ensuing description, with reference balanced by the action of the piston 23 whose position is to the accompanying drawings, of variable-flow drum precisely .determined so that its thrust balances substan piston pumps` incorporating the improvements of the in vention. 10 tially the resultant of the thrusts exerted on the cam by the pump pistons. The inclination or tilt of the cam is In the drawings: controlled by a small piston 25 actuated hydraulically FIG. 1 is an axial sectional view of a pump having two and the return of the cam is ensured by the action of a outer bearings; piston 26 the rear of which is continuously subjected to FIG. 2 is a view partily in »section and partly in plan View taken along line II-I'I of FIG. 1; 15 Lthe delivery pressure. In order to reduce friction, the support plate 1S of the ‘ FIG. 3 is a sectional View taken along line III-_III of shoes 17 of the pistons 16 is driven positively in rotation FIG. 1; ~by means of a .universal joint formed by a thin member F‘IG. 4 is an axial sectional `'view of a modification of a 27 carrying upstanding lugs. Two of these lugs 28 are detail of the pump shown in FIG. 1; 20 disposed in a slot 29 in the plate 18 and two other lugs FIG. 5 is a partial axial sectional view of a modifica tion of the pump shown in FIGS. l to 3 in which the balancing piston of the cam is replaced by a fixed abut ment member rigid with the »housing of the pump; FIG. 6 Yis a sectional view taken along line VI'-VI of FIG. 5; are .disposed in a groove 3,0 orthogonal to the slot 29 and _provided Vin a slide member 31 which is slidable in an axial bore 32 in the rotor and is biased toward the cam 15 by the effect of a return spring 33. The slide 31 is 25 »itselfpositively driven in rotation by the pump body owing to the provision Aof'keying on the shaft 9. This keying is FIG. 7 is an »axial sectional view of a pump having inner bearings and a central shaft; formed, >inthe presently-.described embodiment, by the ' yflat-faced end ¿35 of the shaft 9 which isengaged in the PIG. '7a is a diagrammatic plan view `of :the pump of FIG. 73'showing the forces acting on the barrel and the resultant force thereof; FIG. 7b lis a diagrammatic end view corresponding to FIG. 7a; ~FIG. 8 is an axial sectional view yof a detail of the Amounting of the piston shoes; and s_waged portion 36 of the slide 31. 30 ' In the modification _shown in FIG. .4. the slide 31 is ,driven directly -by ‘the pump body through the medium .of a'pin> í’r’lv or the like forming a key. lIn the'embodiment shown in FIGS.»5 and 6, the bal ,ancing of fthe cram 15 isxensured by the abutment of the FIG. 9 is lan axial sectionalview of a modification of 35 latter against protruding portions or bosses 3S, 38' pro vided onrthe housing 2, the zone of contact between the l6.21m #15 and the portions 38, 38' being a part-cylindrical surface 39 the _axis of the `cylinder coinciding with the pivot axis of the cam, namely, the axis of thepin 20. example, of graphite. ‘The pump body, or rotor, is driven 40 The resultant >of the ¿thrusts exerted on theV cam by the vpump pistonsy -is therefore in this embodiment balanced in rotation bya yshaft 4 -through the medium of a gear 5 Sby 4the reaction iof the housing on the cam. meshing with Aa ring gear >6 whose teeth are machined di In the embodiment shown 'in FIG. >7, the pump is rectly in the rotor 1. ¿the mounting .of -a .piston shoe. In the embodiment shown in FIGS. 1_3, the pump com -prises a-steel pump body or rotor 1 journalled in thehous -ing ‘2 through the medium of 1a bearing 3 composed, for mounted on ka central shaft. The elements corresponding lThe position of bearing 3 is determined by calculation as will -be'explained hereinafter with reference to `embodi 45 .to those of zthe pumps shown in FIGS. 1-3 or 5 and 6 ~carry the same reference characters. ment of FIG. vv7, in order that the resultantof the forces :In this embodiment, the rotorl is ,mounted on a central 'applied on> rotor 1 falls Within the surface fof contact of shaft 40 rigidly fixed in the housing 2 and extend-ing the >distribution member and the rotor 1. Said calcula through the pump. The rotor 1 is journalled on the tion shows here that said bearing 3l ought to be located --between the' vtransverse plane containing the pivot axis 20 50 shaft 40 through the medium of a main anti-friction or roller bearing 41 and a secondary antiafriction or roller of cam or swash plate 15 and vsaid distribution member, 'hearing `42, the play in the latter being greater than that «in the immediate »vicinity of vsaid vtransverse plane. in the bearing 41. The rotorY 1 is driven by the shaft 4 In order to improve the centering of the rotor 1 in the through the medium of the gear 5 .meshed with the ring `-housing 2, `there is provided an additional bearing 7 car gear >«i directly machined in the rotor. ~-ried bythe housing and -in which is journalled the cy "The main bearing 41 isrsituated at the end of the ro ~lindrical -extension'S of a shaft `9 which is fitted by a _tapered portion 10 in the rotor '1 and held fast by a nut 11. . :tory adjacent the lcentrolcam 15 in a region which is de »'The pump comprises pistons 12 -which slide in bores 13 termined by calculation in such manner that the result formed'in ythe rotor, each of these bores being provided ant of the forcesapplied on the rotor 1 is directed toward with‘la liner 14, for example composedof silver, to reduce 60 'the distribution surface 43 and falls within the surface of rcontact of this surface and the adjoining face of the `friction. “The pump delivery or discharge vflow is controlled by `a rotor 1, in order that,'owing to this arrangement, the rotor 1 remains constantly»appliedpagainst the surface 43 ftiltable cam or swash plate 15 against the forward face during pump operation and the presence of the secondary of which the heads »16 of the pistons 12 bear through the medium of their shoes 17 and of a ybearing member, 65 bearing 42 in the vicinity of the face 43 also ensures or plate, 18~ _The _cam 15 carries two ears 19, 19’ provided with vapertures in which is journalled a pivot pin v20 carried by correct application when-the _pump is inoperative. AThe above calculation is made in considering (see FIGS.' 7a and 7b) the rotor 1 and pistons 12, as a whole, _a support ,21 rigid with the housing. This pivot pin is >submitted to the following forces: adapted merely to maintain the cam 15 vin position and 70 (1) Resultaat Fp of the >forces exerted by cam 15 on piston shoes ,17;V _is _only >subjected to a _small force owing to the provision ~of'balancing means which will now be described. ' ‘_,Providedin a bore 22 suitably disposed in the housing, Y’is a piston y23 which is constantly applied by its forward (g2) Driving force (or couple of forces) FM; (3) Hydraulic Aforce FH exerted on rotor'l by the ñuid kbottled up between said rotor »and ¿the distribution trans >face- against the corresponding rear face 24 of «the cam 75 -verse wall 43; 3,075,472 5 (4) Resilient force FR exerted by the resilient mem ber (33, see FIG. 1), if any, to apply the piston heads 16 against cam 15; , (5) Reaction Rp of bearing 41, the moment of which is a function of the distance x between said bearing 41 and said transverse Wall 43; (6) Reaction force RG of the transverse wall 43 on rotor 1. It is the above reaction force RG which is the subject of the calculation and: RG=--e(Fp, FM, FH, FR, Rp). For the calculation, the point of origin of the coordi nates axes is chosen at the center of the distributor trans-r verse wall 43; the axes 0x, oy are in the plane of said wall 43, oy being directed towards the delivery port 45. The magnitude and point of application of the diiîer 15 ent forces are determined by the following considerations: (1) Resultant FP of the forces exerted by the cam 15 on the piston shoes 17 is perpendicular to said cam (pro viding there is no substantial friction); its point ,of appli cation is at the center of gravity of the half-circle having 20 a radius b equal to the boring radius of the piston bores, and its component parallel to the axis oz balances the force F generated by the delivery pressure of the pump applied to half of the number of pistons 12. (2) Driving force FM has its point of application at 25 the meshing point of driving gear 5 with thetoothed ring 6, its direction is defined by the pressure angle of the gear teeth, and its magnitude is determined by the fact that themoment, relative to axis oz, of its compo nent parallel to 0x, balances the moment, rela-tive to the 30 same axis, of FP. When the rotor is driven through an axial drive, the driving shaft applies to the rotor a pure torque. (3) The hydraulic force FH applied to the rotor is 5 on the end 47 of the shaft 20 and extends out of the housing through a suitable aperture. In the embodiment shown in FIGS. 1 to 7, the spheri cal heads 16 of the pistons 12 are set into the shoes 17 and the latter bear on the cam 15 by their flat faces 47. In order to reduce friction, the shoe is covered on this face with a suitable electrolytic deposit or the cam is composed, for example, of graphite. In the embodiment shown in FIG. 8, the shoe 17 corn prises a recess 48 in which is disposed a thin friction plate 49 which protrndes from the face 4‘/ of the shoe. Thus, the piston bears against the cam 15 solely through the medium of this plate 49 which is provided with an aper ture 5t) for the passage of lubricating oil. This plate is composed of a metal having a good coefficient of friction, «for example silver, and is easily changed when worn out. In the modiñcation shown in FIG. 9, the frictionplate is replaced by a substantially r’rusto-conical element 51 Whose flat lface 52, protruding from the face 57 of the shoe 47, bears against the cam I5. The inner part 53 of the element 5I, disposed in an aperture of corresponding shape formed in the shoe, has a part-spherical concave shape and extends inwardly of the shoe. The recess in the shoe receiving the piston head has such shape that the piston head 16 is merely retained by the edges 54, it bear ing solely against the concave part 53 of the element 51. Thus, friction both inside and outside the shoe only results in Wear of the element 53 which is easily changed. Although specific embodiments of the invention have been described, many modifications and changes may be made therein without departing from the scope of the invention as defined in the appended claims. Thus, the pistons need not be parallel with one another and the shaft j‘ournalled in the lateral bearing could be mounted parallel to oz and its point of application is at the center 35 in the rotor by means other than a tapered extension held of gravity of the half-circle having a radius c equal to the in place by a nut. mean radius of the delivery and induction ports 45, 46, What I claim is: its magnitude is equal to the product of F and a factor 1. In a pump of the drum piston type comprising a which depends on the balancing coefficient of the pump. housing having a transverse wall and provided with an (4) Force FR, in the case of an axial spring 33 (see induction passageway and a delivery passageway opening FIG. 1) is applied at the origin of the coordinates axes on said transverse wall of said housing, a rotor mounted and is parallel to oz. for rotation about an axis in said housing and having a (5) The reaction force Rp of the bea-ring 4l is perpen lateral face in contact with a corresponding surface of dicular to oz and balances all components of the afore said transverse Wall and bores opening on said lateral said forces which are perpendicular to oz. face, pistons disposed for reciprocation in said bores and (6) And the reaction force RG of the transverse wall having each a part-spherical head outside said rotor, a 43 on rotor 1 is parallel to oz; its magnitude is equal to: cam having a ñat face cooperating with said heads of FH-F-FR and its point of application in the plane of transverse wall 43 is determined by writing that the said pistons for controlling the movement of said pistons in said rotor, a shoe mounted on each of said heads of moments of said force RG relative to axes ox and oy 50 said pistons and having a flat face resting against the said are, respectively, equal to the sums of moments of afore ñat face of said cam, a retaining plate for biasing said said forces relative to the corresponding axes. shoes against said cam, a spring biased member axially and slidingly mounted in said rotor, said spring biased member and said plate providing contacting surfaces be inside the circle having the radius r of the distributor 55 tween the spring biased member and the plate, said con transverse member 43 give the limits between which is tacting surfaces providing grooves and projections fitting to be located the main bearing 41, to be sure that rotor 1 in said grooves for positively driving the plate via the remains always correctly applied against said transverse spring biased member. wall 43 to provide a perfect working of the pump. 2. In a pump of the drum piston type co-mprising a The coordinates of said point of application of RG being thus calculated, the conditions for said point to be The secondary bearing 42 is in the sa-me transverse 60 housing having a transverse wall and provided with an plane perpendicular to the shaft 40 as the ring gear 6 induction passageway and a delivery passageway opening which is obviously most advantageous and only possible with a rotor mounted on a central shaft. on said transverse wall of said housing, a rotor mounted for rotation about an axis in said housing and having a The line of meshing between the gears 5 and 6 is in the lateral face in contact with a corresponding surface of same plane as the axis of the induction passageways 44 65 said transverse Wall and bores opening on said lateral and delivery passageways 45 and on the side of the axis face, pistons disposed for reciprocation in said bores and of the rotor opposed to that of the delivery passageway having each a part-spherical head outside said rotor, a 45. The application of the rotor against the distribution cam having a flat face cooperating with said heads of surface 43 is thereby still further improved. The cam 15 abuts, through the medium of a cylindrical 70 said pistons for controlling the movement of said pistons in said rotor, a shoe mounted on each of said heads of boss formed thereon, against the parts 38 having corre said pistons and having a ñat _fa-ce resting against said sponding shape of the housing 2 and can be tilted by a dat face of said cam, a retaining plate for applying said shaft 20 which is integral therewith and disposed in a shoe against said cam and having a hemispherical por corresponding bore in the housing. The tilting of the cam 20 is controlled by a control lever 46 which is ñxed 75 tion, a spring biased member axially and slidingly 3,075,472 8 7 tween the Vtransverse plane containing Vthe Aaxis oirocking mounted in said rotor but keyed in rotation with _said rotor and having a hemispherical portion fitting with said movement of said cam and said’transverse’walrlat .ai'disyA hemispherical portion of said retaining plate'for urging tance from said transverse Wall such yas to have said _reac-l said plate landsaid shoes towards said cam, grooves on tion force exerted lby said transverse vwall Non' said vrotor fall inside said corresponding surface of Asaid1transvelrse one ,of said corresponding hemispherical portions Vof said Wall and be directed towards said rotor. retaining plate and said Vspring biased members, _and pro iections on the other of said hemispherical portions en ’ 4. In la pump as in claim 3, further comprising aV sec gaging vvith and cooperating with said grooves. ondary bearing located substantially in the plane containf induction passageway and adelivery passageway opening _5. VIn a pump as‘in claim 3, wherein said ldelivery _pas sageway is located in the axial plane >containing _thelineof mesh between said toothed ring and said gear on the side of >the axis of the ïotor opposed to that y,of said line ing said toothed ring and supporting said rotor with `a 3. I_n a pump ofv the drum piston type comprising a housing having a‘transverse Wall and provided with an l0 play exceeding the play of said main bearing. on said transverse Wall of said housing for circulation ofthe fluid to be circulated by said pump,` a rotor mounted Ifor rotation about an axis in said housing and having a lateral face incontact With a corresponding surface of 15 ~said transverse Wall exerting on said rotor a reaction force substantially perpendicular ,to said lateral face and bores opening on said‘lateral face,- pistons disposed for recipro cation in said bores and having each a head outside said rotor, a cam cooperating with said heads for controlling 20 the'movement of rsaid pistons in said rotor comprising a Ísupport mounted for rocking movement about an axis ex ltending at right angles to the axis of rotation of ,Said rotor and exerting'on >said piston heads forces ywhich have va resultant perpendicular to saidicam, -resilient means urging said pistons against ysaid cam thereby exerting a force .on said rotor, a -toothed ring 'directlyv machined in the lateral face .of said rotor,~ and Aa 4driving shaft >having lits _axis parallel to .the axis of rotation of said rotor, a gear carried by said driving shaftand Ámeshing _with said 30 ltoothed ring for rotating said rotor and .exerting on said _rotor ya driving force, a .main bearing »for supporting said rotor in Vsaid Vhousing and `exertingon said ‘rotor a bearing reaction force substantially perpendicular to said Y.axis of ,said `rotor and _forming with said resultant force .exerted 35 by said cam on said piston heads, said-,hydraulic force, said driving force, said force exerted byfsaid ¿resilient ofmesh. sultant, said main ,bearing being located in a plane be ' " References Cited in the tile `of this patent . UNHED .SïATsS „PATENTS » 1,418,951 Martin _______________ _.. June 6, A192?. 1,710,567 Carey ..-_Q___________ __Ápr. 23, 1929 1,996,889 Thomas ...._...'._V_ _______ _.. Apr. «9,4193-5 2,063,464 Schindler ______________ _; Dec. 8,1936 2,284,146 Herman4 _________ __`_A___ -Mayi2`6', »1942 2,480,069 Wright _______ _-,_ ____ __ Ang. 23, .1949 2,484,337 Ferris ____ __v.`____l____p_'_..o'ct,f11, 11949 2,502,546 Adams ____-_-_.___s .... __ Apr. 4, 1950 2,543,624 2,549,711 Gabriel À__-_______ 1....'.5112615.- 27, 1951 Ruben ______________ _~__ Apr. 17,1951 `2,642,809 Born et a-l ____________ -_ June 23,1953 2,699,123l Bonnette et al. ________ „Jans-11', 1955 2,716,944 Ferris _________ _d ____ __’_.'Sept. 6, `11955 2,733,666 Poulos ______________ __'- Fe'b. 7, 1956 >2,776,629 .Keel ____ __j _________ __'__ Jan; 8', 1957 V2,800,082 >Aspelin __________ __',____<Ju1y123, '1957 v2,880,042 Budzich ____ _.’..r._-_j___.._ ¿Man '311, 1959 2,895,426 -orshans-ky `___-'_'-__’_"__j'__'1ú1`y p21; V1’9'5'9 _FOREIGN PATENTS I 119,044 Switzerland ___________ -_'Mar.11, y1927 meansand said reaction -force'exerted by said transverse ,wall on said rotor a system of forces having a zero re 40 "