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Publication numberUS3289542 A
Publication typeGrant
Publication dateDec 6, 1966
Filing dateOct 29, 1963
Priority dateOct 29, 1963
Publication numberUS 3289542 A, US 3289542A, US-A-3289542, US3289542 A, US3289542A
InventorsFikse Tyman H
Original AssigneeLawrence Machine & Mfg Company
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Hydraulic motor or pump
US 3289542 A
Abstract  available in
Images(9)
Previous page
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Claims  available in
Description  (OCR text may contain errors)

Dec. 6, 1966 T. H. FxKsE: 3,289,542

HYDRAULIC MOTOR OR PUMP Filed Oct. 29, 1965 9 Sheets-Sheet l INVENTOR v cu Tymon H. Fikse WMWMQQM ATTORNEYS Dec. 6, 1966 T. H. FlKsE HYDRAULIC MOTOR OR PUMP 9 Sheets-Sheet 2 Filed Oct. 29, 1963 INVENTOR Tymon H Flks ATTORNEYS BY/JMMMM Dec. 6, 1966 T. H. FlKsE 3,289,542

HYDRAULIC MOTOR 0R PUMP Filed 001'.. 29, 1963 9 Sheets-Sheet 3 FIG. Il

INVENTOR T`ymon H. Fkse BY/Q/MMVOQM ATTORNEYS HYDRAULIC MOTOR OR PUMP Filed Oct. 29,V 1963 9 Sheets-Sheet INVNTOR Tymon H. Fkse BY/JMMM ATTORNEYS Dec. 6, 1966 T. H. FlKsE 3,289,542

HYDRAULIC MOTOR OR PUMP Filed Oct. 29, 1963 9 Sheets-Sheet 5 INJECTION BEGINS EXHAUST ENDS 2 INJECTION ENDS EXHAU T INVENTOR Tymon H. Fikse Inv/@VM ATTORNEYS Dec. 6, 1966 T. H. FlKsE HYDRAULIC MOTOR OR PUMP 9 Sheets-Sheet 6 Filed Oct. 29, 1963 INVENTOR Tyman H. Fikse mmm CNN

.Q @Pi ATTORNEYS HYDRAULIC MOTOR OR PUMP Filed Oct. 29, 1953 9 Sheets-Sheet 7 1N VENTOR Tymun H. Fikse BYMMQM ATTORNEYS Dec. 6, 1966 T. H. FnKsE HYDRAULIC MOTOR OR PUMP 9 Sheets-Sheet 8 Filed oct. 29, 3.963

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INVENTOR Tymon H. Fkse ATTORNEYS Dec. 6, 1966 T. H. FlKsE 3,289,542

` HYDRAULIC MOTOR 0R PUMP Filed oct. 29, 196:5 9 sheets-sheet 9 INVENTOR Tymon H` Fkse BY/MMMUJM ATTORNEYS' United States Patent C) 3,289,542 HYDRAULIC MOTOR OR PUMP Tyman H. Fikse, Enumclaw, Wash., assignor to Lawrence Machine & Manufacturing Company, Seattle, Wash., a corporation Filed Oct. 29, 1963, Ser. No. 319,776 I Claims. (Cl. 9I-56) The present invention relates to rotary power conversion devices and more particularly to rotor pumps and motors of the type wherein interengaging relatively rotatable elements provide expansible fluid chambers.

The type of power conversion devices with which the invention Vis primarily concerned is disclosed by United States Letters Patent No. 2,821,171 issued to Lynn L. Charlson on January 28, 1958. In conventional iiuid pressure devices ot this type, a peripherally lobed rotor engages an internally lobed stator and moves in a hypocycloidal orbiting path about the stator axis. By providing the rotor with fewer lobes than on the stator, the rotor is rotated about its axis as it travels in its orbital path within the stator to thereby establish a plurality of expansible fluid chambers which continuously vary in size.

In one important aspect, this invention contemplates an efficiently organized, mechanically simple, easily assembled power conversion device of the interengaging rotor and stator type particularly adapted to translate Huid pressure into mechanical movement. In another of its important aspects, the present invention contemplates a novel iluid motor having a special operating fluid intake and exhaust arrangement which allows a continuous driving force to be applied to a power output element. In another important aspect, this invention provides a hydraulic motor which operates eiliciently and which has along, useful life.

While the invention as `described herein is directed to a rotary uid motor, it is also applicable, in certain aspects, to rotary pumps.

Accordingly, it is a major object of the present invention to provide a novel rotary fluid motor or pump of the expansible chamber type wherein the internal parts are easily and quickly assembled and dismantled.

More specifically it is an object of the present invention to provide a novel rotary iluid motor wherein all of the internal operative parts providing the expansible iluid chambers and the inlet and exhaust of fluid relative to the chambers are so arranged in side-by-side relationship that they are axially removable and insertable through a single opening in the motor housing.

Still Aanother object of the present invention is to provide a novel rotary tiuid motor or pump providing for a compact but accessible arrangement of internal parts.

A further object of this invention is to provide a motor which operates eiiciently with minimized mechanical friction and which has a long, useful life.

Another important object of the present invention is to provide a rotary uid motor with a novel uid intake and exhaust port arrangement providing cyclic overlapping injection periods for a plurality of iluid operating chambers to thereby apply a continuous driving force to a power output element.

Still another object of the present invention is to provide a novel hydraulic power unit having lobed interengaging rotor and stator elements deiining a plurality of expansible and contractible motor operating chambers, wherein one of the elements is specially constructed to obviate scarring and scuing of the engaging rotor and stator element surfaces as a result of pressure fluid trapped between meshed parts of the rotor and stator.

Further objects of the invention will appear as the 3,289,542 Patented Dec. 6, 1966 ICC description proceeds in connection with the appended claims and the annexed drawings wherein:

FIGURE 1 is a longitudinal section of a rotary uid motor incorporating the principles of the present invention;

FIGURE 2 is a partially sectioned view taken substantially along lines 2 2 of FIGURE l;

FIGURE 3 is an elevation 0f the Huid motor stator illustrated in FIGURES l and 2;

FIGURE 4 is an enlarged exploded longitudinal section of the coupling assembly shown in FIGURE l and non-rotatably securing the motor valve plate to the motor rotor;

FIGURE 5 is an end elevation of the valve plate coupling element illustrated in FIGURE 5; l

FIGURE 6 is an enlarged fragmentary section taken along lines 6-6 of FIGURE 1;

FIGURE 7 is `an elevation of the operating fluid inlet port plate shown in FIGURE l;

FIGURE 8 is a section taken substantially along lines 8-8 of FIGURE 7;

FIGURE 9 is an elevation of the valve plate illustrated in FIGURE 1;

FIGURE l0 is a section taken substantially along lines 10--10 of FIGURE 9;

FIGURE l1 is a section taken substantially along lines 11--11 of FIGURE 3;

FIGURE 12 is a section taken substantially along lines 12--12 ot FIGURE 1 and illustrating the relationship of the fixed inlet plate ports with the rotating valve plate ports;

FIGURE 13 is a section taken substantially along lines 13--13 of FIGURE 1 and illustrating the relationship of the valve plate ports with the fixed exhaust passages in the motor stator;

FIGURE 14 is a timing chart illustrating the fluid inlet, exhaust, and power stroke periods for one of the expansible fluid motor chambers defined between the interengaging stator and rotor of the motor;

FIGURE 15 is a longitudinal sectional view of a rotary iluid motor according to another embodiment of the present invention;

FIGURE 16 is an enlarged fragmentary view of the motor parts shown in FIGURE 15 and contained in a circle designated by the reference character B;

FIGURE 17 is an elevation of the modied motor valve plate illustrated in FIGURE l5;

FIGURE 18 is a section taken substantially along lines 118-18 of FIGURE 17;

FIGURE 19 is an elevation of the modified motor port plate illustrated in FIGURE l5;

FIGURE 20 is a section taken substantially along lines 2tl-20 of FIGURE 19;

FIGURE 21 is a longitudinal sectional view of a rotary uid motor according to still another embodiment of the present invention;

FIGURE 22 is a longitudinal section of the motor illustrated in FIGURE 2l, but annularly offset from the plane in which the section of FIGURE 2l is taken to illustrate details of the system fluid inlet passages; and

FIGURE 23 is a section taken substantially along lines 23-23 of FIGURE 21.

Referring now to the drawings and more particularly to FIGURES l and 2; the invention will be described as applied to a uid motor generally designated by the reference character 20 and comprising a hollow generally cylindrically shaped housing 22 that is open at both ends. At one end, housing 22 is provided with a boss 24 having radial fluid inlet and outlet ports respectively comprising through bores 26 and 2S which are threaded at their outer ends to receive fluid supply and return conduits 3 (not shown). The axes of bores 26 and 28 are parallel and are axially spaced apart in a common plane.

With continued reference to FIGURES 1 and 2, bores 26 and 28 communicate at their inner ends with an .enlarged cylinder space 30 (FIGURE 2) delimited by a smooth uniformly diametered internal cylindrical wall surface 32 coaxially formed in housing 22. Cylinder space 30 is enclosed at its outer end by a cover plate 34 detachably secured to housing 22 as by a series of circumferentially spaced apart machine screws 36. An annular locating extension 38 (FIGURE l) formed integral with cover plate 34 and extending coaxially into housing 22 snugly bears against cylindrical surface 32 and is undercut to provide an annular surface 40. Radially compressed between surfaces 32 and 40 is a resilient 'O-ring 42 which provides a fluid tight seal.

As best shown in FIGURES 1, 2 and 3, a stator 44 coaxially mounted in cylinder space 30 comprises a flatsided annular member having a smooth uniformly diametered external peripheral surface 45 snugly seated on housing surface 32. Resilient O-rings 46 and 48 sealing against surface 32 are respectively seated in radially outwardly opening axially spaced apart grooves 50 and 52 formed in stator 44.

Stator 44 is provided with a series of equiangularly spaced apart radially inwardly extending lobes or teeth 54 which are preferably of uniform contour. A rotor 56 surrounded by stator 44 is formed with a series of radially outwardly extending equiangularly spaced apart uniformly contoured lobes or teeth 58 preferably one less in number than and meshing with stator lobes 54. In the present embodiment, there are eight rotor lobes and nine stator lobes.

As will be described in greater detail later on, rotor 56 is mounted to orbit in a closed eccentric hypocycloidal path about the longitudinal axis of stator 44. Thus, each of the rotor lobes S8 will move into and out of engagement with stator lobes 54 as rotor is eccentrically displaced in its orbital path within stator 44 to provide a series of closed fluid chambers 62 (FIGURE 2) which continuously vary in size. Owing to the rotor and stator lobe arrangement and particularly to the difference in the number of rotor and stator lobes 54 and S8, all but one of the rotor lobes 58 will be at least partially meshed with stator lobes 54 all lof the time but only one of the rotor lobes 58 will be fully meshed `between adjacent stator lobes 54 at any given time. With this arrangement, rotor lobes 58 are always in fluid sealing engagement with adjacently disposed stator lobes S4 thereby isolating the respective chambers 62 from each other in the manner best shown in FIGURE 2. Introduction of pressure fluid into chambers 62 by means to be described later on, displaces rotor 56 in its orbital path and rotates the rotor about its own axis in predetermined relation to the rotor orbital displacement as determined by the difference in the number -of rotor and stator lobes.

The foregoing rotor and stator lobe arrangement and constuction and the eccentric orbital and rotational movement of rotor 58 within stator 44 is more fully described in the previously mentioned United States Letters Patent No. 2,821,171 and the patents referred to therein.

As shown in FIGURE 1, rotor 56 is coaxially formed with an internally axially splined through bore 64 nonrotatably c-onnected to a drive link 66 by segmental spherical splines 68 on a knuckle 70 integrally formed at one end of link 66 and projecting into bore 64. Knuckle 70 is of such segmental spherical shape as to permit drive link 66 to be universally rocked as rotor 56 is displaced in its eccentric orbital path. Drive link 66 extends axially towards the end of housing 22 opposite from cover plate 34 and terminates in another knuckle 72 projecting into a blind stepped bore 74 coaxially formed in the inner end of a power output shaft 76 which extends along an axis coaxially yaligned with the stator axis.

With continued reference to FIGURE 1, link 66 is nonrotatably and rockably connected to output shaft 76 for relative universal movement by axial splines 77 formed in bore 74 and engaging segmental spherical splines '78 on knuckle 72. The longitudinal axis of drive link 66 intersects the common axis of stator 44 and output shaft 76 at an acute angle and passes through the spherical centers of knuckles 70 and '72. The spherical center of knuckle 72 is coincident with the point of intersection of the drive link axis and the output shaft axis as shown.

Rotatably supporting shaft '76 in housing 22 are axially spaced apart conventionally constructed anti-friction bearing assemblies 79 and 30 having their outer races snugly seated in a cylindrically smooth recessed bore 82 formed in the end of housing 22 opposite from cover plate 34. Output shaft '76 is stepped to provide cylindrically smooth axially spaced apart bearing support sections 84 and S6 separated by an enlarged diametered cylindrical section 88 and respectively seating the inner races of bearing assemblies 79 and 80. Bearing assembly 79 is axially confined in place between an internal annular shoulder 90 formed in housing 22 at the base of bore 82 and an annular shoulder 92 formed on shaft 76 at the juncture between shaft sections 84 and 88. Bearing assembly 80 is held axially against a shaft shoulder 94 formed at the juncture of sections 86 and 8S by a retainer ring and groove assembly indicated at 96.

From the foregoing structure it is clear that the universal splined connections of drive link 66 permits rotor 56 to be displaced in its eccentric orbital path about the stator axis and transmits rotary movement of rotor 56 to drive shaft 76 which projects axially beyond housing 22 for connection to a driven mechanism (not shown).

In accordance with the present invention, stator 44 and rotor 56, as shown in FIGURE 1, are formed with ush flat side surfaces extending at right angles to the aligned axes of stator 44 and housing 22 and seated against a valve plate on one side and a flat sided Wear plate 102 onthe other side. Chambers 62 are bounded at opposite ends lby plates 100 and 102 respectively.

Wear plate 102 is axially retained in place between the sub-assembly of stator 44 and rotor 56 and a at annular shoulder 104 internally formed in housing 22. A cylindrical pin 106 non-rotatably securing stator 44 and wear plate 102 to housing 22 is snugly received in a shallow fiat Ibottomed cylindrically walled recess 108 formed in stator 44 and extends through an aperture 110 in Wear plate 102 along an axis parallel to and laterally offset from the longitudinal axis of housing 22. Pin 106 extends beyond wear plate 102 and into an axial blind bore 112 formed inwardly of shoulder 104. Stator 44 and wear plate 102 are thus held against rotation by pin 106. As shown, wear plate 102 comprises an annular member having a central aperture 114 through which drive link 66 freely extends. Both stator 44 and rotor 56 seat axially against plate 102.

With continued reference to FIGURE 1, valve plate 100 comprises a flat sided member coaxially formed with a cylindrically bored opening 117 and axially seated Iagainst the flush sides of stator 44 and rotor 56. Valve plate 100 is non-rotatably fixed to rotor 56 by a coupling assemlbly 118 comprising coacting rotor and valve plate coupling elements 120 and 122. As shown, the longitudinal axis of valve plate 100 is axially aligned with the longitudinal stator axis.

Coupling element 120, as shown in FIGURES 1 and 4, comprises a disc shaped body portion 124 coaxially and slidably extending into rotor `bore 64 from the end opposite from drive link 66. The part of body portion 124 received in lbore 64 is axially splined at 126 to non-rotatably engage the internal rotor splines in bore 64. An annular stop shoulder 128 formed on the end of body portion 124 projecting beyond :bore 64 limits axial inward displacement of element 120 into bore 64.

With continued reference to FIGURES 1 and 4, coupling element 120 is formed with a flat end face 132 from which a diametrical flat-sided key portion 130 integrally projects. Key portion 130 is snugly received in a diametrical keyway 134 formed in coupling element 122. Coupling element 122 axially bears against end face 132 in axially aligned relationship with coupling element 120 and is received in opening 117 in eccentric relationship to the longitudinal axis of valve plate 101i.

As best shown in FIGURES 1 and 6, coupling element 122 is formed with a diametrical keyway 136 extending at right angles to keyway 134 and opening in the opposite direction towards cover plate 34. An elongated key 140 slidably received in keyway 136 projects at both ends axially beyond element 122 and interfittingly extends into diametrically aligned keyways 142 and 144 (FIGURE 6) formed in the side of valve plate 101i facing away from stator 44. Thus, valve plate 100 is rotatable with rotor 56 about an axis axially aligning with the stator axis.

With continuing reference to FIGURE 1, key 140 is provided with a iiat outwardly facing surface 146 which is flush with the side surface 147 of valve plate 100 facing towards cover plate 34. A Hat-sided disc shaped port plate 150 is axially confined between valve plate 101) and a iiat annular end face 152 formed on cover plate extension 38. Axial confinement of valve plate 100 between stator 44 and plate 150 is suficiently loose so that plate 101) is free to rotate with rotor 56. End face 152, shoulder 104, and the fiat sides of wear plate 102, valve plate 100, port plate 150, stator 44, and rotor 56 are contained in parallel planes passing at right angles to the common axis of housing 22 and stator 44.

Port plate 150 is provided with a smooth cylindrical periphery :slidably and coaxially seated on surface 32 in cylinder space 30. Axially spaced apart groove-seated O-rings 158 and 160 are carried 'by plate 150 and are radially compressed against surface 32 to provide a iiuid tight seal. A cylindrical pin 162 having opposite ends slidably received in aligned laterally offset blind lbores 164 and 166 respectively formed in cover plate 34 and port plate 150 iix port plate 150 against rotation.

From the foregoing structure, it is clear that plates 100, 102 and 150, stator 44 and rotor 56 are axially conined in plate between shoulder 104 and cover plate 34 by tightening screws 36. Plates 100, 1112 and 150, stator 44 and rotor 56 are easily and quickly assembled in place or removed by sliding these parts through the open end of housing 22 closed by cover plate 34.

To introduce iiuid under pressure for operating iiuid motor 2t), port plate 1511, as shown in FIGURES 1, '7 and S, is formed with an annular outwardly opening groove 170 disposed axially between O-rings 158 and 160 and defining an annular iiuid inlet chamber 171. Groove 171) radially aligns and communicates with the pressure uid inlet bore 26 as shown in FIGURE 1. Communicating with chamber 171 are a series of nine equiangularly spaced apart generally axially extending uniformly dimensioned identical fluid passages 172 (FIG- URES 1, 7 and 8) open on the side toward valve plate 100 and disposed along a common circumference radially outwardly of the pockets between stator lobes 54. Passages 172 are adapted to cyclically register with eight equiangularly spaced apart identical uniformly dimensioned ports 174 (FIGURES 6, 9 and 10) formed in and extending Iaxially through valve plate 100 about a common circumferen-ce.

Valve plate ports 174 function both as intake and exhaust ports and are uniformly contoured in the shape of key holes each having an inner partial circular por-tion 176 and an elongated relatively narrow slot portion 178 extending radially outwardly from portion 176. Ports 174 are each symmetrical about a radius of valve plate 100. Portions 176 and 178 of ports 174 are so disposed as to respectively register with the fluid motor chambers 62 and passages 172 in port plate 150. According to the present invention, the number of ports 174 is preferably equal to the number of rotor lobes 58 which, in the present embodiment, is eight. Thus, the angular spacing between center lines of adjacently disposed ports 174 is 45 degrees as best shown in FIGURE 9.

As best shown in FIGURE 7, there are nine passages 172 corresponding in number to stator lobes 54 and providing an angular spacing of 40 degrees between diametrically extending 4center lines of adjacent passages. The arrangement of passages 172 in plate 150 is such that each passage 172 will be offset from the crest of one of the stator lobes 54 by a fixed angular distance of 10 degrees.

With the foregoing number and arrangement of passages 172 and ports 174, three adjacent and seriate ports 174 will register simultaneously with a corresponding number of adjacently disposed passages 172 at any an* gular position of valve plate as shown in FIGURE 12 and indicated by the reference characters 17451, 1'74b, and 174e respectively. As a result, pressure iiuid is admitted simultaneously to three seriate chambers 62 at any given angular position of valve plate 100.

When port 174b fully registers with the inlet passage indicated at 172]: in FIGURE 12, ports 174a and 174C partially register with the inlet passages indicated at 172a and 172e` respectively. As valve plate 101i is rotated in a counterclockwise direction from the position shown in FIGURE 12, the leading valve port 17461 will move out of registry with any of the inlet passage 172, port 174b will only partially register with passage 17211, port 174e will move into full registry with passage 172C and the next valve plate port indicated at 174d will move into partial registry with the next inlet passage indicated at 172d. Registration of ports 174 with inlet passages 172 continues to change in this manner as valve plate 101) is rotated with three seriate ports 174 always being in registry with three seriate inlet passages 172.

Valve ports 174 and inlet passages 172 are so dimensioned and arranged that the pressure fluid injection period for each chamber 62 lasts for an 18 degree angular displacement of valve plate 160. This is essentially accomplished by making the correspond-ing arcuate distances of passages 172 and ports 174 indicated at A in FIG- URE 12 substantially equal to nine degrees.

To exhaust iiuid from chambers 62, stator 44 is formed with a series of uniformly dimensioned outlet passages adapted to register with portions 178 of ports 174 and spaced equiangularly about a common circumference as best shown in FIGURES 1 and 3. Passages 181i extend axially inwardly and communicate at their inner ends with an annular chamber 182 (FIGURE 1) defined by an annular radially outwardly opening groove 134 (FIGURES 1 and 11) formed in stator 44 and radially aligning with the fluid outlet bore 23. In the present embodiment, the number of passages 180 are equal to that of passages 172 but are angularly offset from passages 172 by 20 degrees. Thus, only three seriate stator passages as indicated at 180er, 181111 and 180e in FIGURE 13 will register with oppositely disposed ports 174 throughout the rotation of valve plate 1111i.

The position of valve plate 1M) illustrated in FIGURE 13 is the same as that shown in FIGURE 12. Thus passages 18tla, 189k and 180C are shown to register with ports 174e, 174f and 174g which are respectively diametrically opposite ports 174a, 174b and 174C registering with inlet passages 17261, 172b and 172C. Consequently, fluid is exhausted through ports 174e, 174]c and 174g simultaneously with admission of pressure fluid through ports 1745i, 1741; and 174C.

The dimensions of exhaust passages 180 are made the same as those for inlet passages 172 so that the exhaust period for each chamber 62 will last for a valve plate angular displacement of substantially 18 degrees.

Turning now to the timing chart illustrated in FIGURE 14, the injection, power stroke and exhaust cycles for one chamber 62 and an associated valve plate port 174 7 will be described. Injection of motor operating fluid into the motor chamber indicated at 62d in FIGURE 13 begins when valve plate liti@ is rotated in a counterclockwise direction (as viewed from FIGURES 12 and 13) to register port 174d with inlet passage 172d. Port 174rl remains in registry with inlet passage 172d injecting motor operating fluid into chamber 62d for a counterclockwise angular displacement of valve plate 106 of 18 degrees. At this point, injection of pressurized fluid ends and with both intake and exhaust closed to confine the operating fluid in chamber 62d for a substantially two degree displacement of valve plate 100. At this point, port 174d moves into registry with the exhaust passage indicated at 18041 in FIGURE 13. Exhaust of fluid continues for 18 degrees travel of valve plate 100 and then closes. After a further -angular displacement of two degrees, port 1'74d registers with inlet passage 172C to start a new injection cycle. The fluid intake and exhaust cycles for the remaining chambers 62 is the same as described above.

From the foregoing it is clear that the angular displacements of valve plate 100 for injection and exhaust are the same and are considerably greater than the dis placement of valve plate 100 while fluid is confined in each chamber 62. Also, the operating fluid injection and exhaust periods relating to each of the valve plate ports 174 overlaps with the corresponding periods of the next two seriately disposed valve plate ports. For example, when port 1745i passes out of registry with intake passage 172a thus ending the injection period for port 174a, the injection periods for ports 174b and 174e are already in progress since ports 174b and 174e are registering with passages 172b and 172e respectively. Before port 174-b passes out of registry with intake passage 172b, port 1741i comes into registry with intake passage 172:1 so that the injection periods for each group of three Seriate valve plate ports 174 are overlapping. This provides for a continuous application of fluid pressure to drive rotor 54 and, hence, shaft 76. The same overlapping relationship exists for the exhaust periods of each group of three Seriate ports 174.

With reference now to FIGURES 1 and 9, it will be seen that valve plate is provided with a set of three equiangularly spaced apart axially extending through bores 200 having uniform diameters and disposed along a common circumference between each pair of adjacent ports 174, As valve plate 10d is rotated, bores 2th) will register with a series of flat bottomed pockets 262 (FIG- URE 7) formed in plate 154i and with a series of flat bottomed pockets 204 (FIGURE 3) in stator 44.

As best shown in FIGURE 7, one pocket 202 is dis. f

posed equiangularly between each pair of adjacent inlet passages 172 and opens axially towards valve plate 11MB so as to communicate with bores 20? as plate 1G@ is rotated.

As shown in FIGURE 3, one pocket 204 similarly is disposed equiangularly between each pair of adjacent exhaust passages 18) and opens axially toward plate 10@ to communicate with bores 200. Pockets 202 and 264 are axially aligned with exhaust passages 180 and intake passages 172 respectively.

As valve plate fitti rotates about the axis of stator 44, corresponding ends of bores 200 will alternately register with pockets 202 and intake passages 172. At the same time the opposite ends of bores 26M) will alternately register with exhaust passages 18@ and pockets 204. This establishes intermittent fluid communication between pockets 202 and exhaust passages 13d and between pockets 204 and intake passages 172 to balance the hydraulic fluid pressures on opposite sides of valve plate 100.

With the interengaging rotor and stator construction of the type described above, it was found in this invention that some motor operating fluid is trapped between rotor lobes 58 and the pockets in stator whenever the former full mesh with the latter. This trapped fluid, especially if it is incompressible oil, creates an unbalanced condition in that it pushes rotor 56 radially upwardly from the position of parts shown in FIGURE 2. As a result, the engaging surfaces of rotor lobes 5S and stator lobes 54, which are at the upper region of cylinder space 3l) in FIGURE 2, are likely to be scarred and eventually require replacement.

The damage to rotor 56 and stator 44 resulting from the objectionable condition of trapped system uid is corrected in this invention by providing rotor 46 with chamfers 211i (FIGURE 2) which extend only between lobes 58. Each chamfer 210 terminates at opposite ends at the bases of adjacent lobes 58 and continuously extends around the pocket between the lobes. This rotor chamfer construction provides a deliberate but small pressure leak along the marginal rotor edges extending between lobes 53 to relieve fluid pressure which otherwise would be trapped between fully meshing rotor lobe and stator pocket portions. As a result, a balanced fluid condition is maintained, and objectionable damage to rotor 56 and stator 44 is avoided.

FIGURES 15-20 illustrate a modified hydraulic motor 220 constructed according to another embodiment of the invention, and to the extent that it is the `same as the motor shown in FIGURES l14, identical reference numerals have been used to designate like parts. Motor 226, as shown in FIGURE l5, comprises a housing assembly 222 having a hollow generally cylindrical part 224 which is axially open at both ends. Housing part 224 is diametrically enlarged at one end to provide a motor operating cylinder space 226 delimited by a smooth uniformly diametered internal cylindrical wall surface 22S. Adjacent this enlarged end, housing part 224 is integrally formed with a radial mounting flange 23@ by which motor 220 is adapted to be mounted on a frame or other structure. Like the housing in the previous embodiment, part 224 is provided with radial fluid inlet and outlet ports respectively comprising bores 232 and 234 which are enlarged and threaded at their outer ends to receive system fluid supply and return conduits (not shown).

With continued reference to FIGURE l5, cylinder space 226 is enclosed at its outer end by a cover plate 236 which is detachably fixed to the enlarged end of housing part 224 by a plurality of circumferentially spaced apart cap screws 238. Cover plate 236 is provided with an annular locating extension 240 which slidably extends into housing part 224 in bearing engagement with surface 228. A grooved-seated resilient O-ring 242 carried by extension 246 is radially compressed against surface 228 to provide a fluid tight seal.

Mounted in cylinder space 226 in the same manner as described in the previous embodiment are stator 44, rotor 56, wear plate 1.02, a modified valve plate 244, and a modified stationary port plate 246. To the extent that plates 244 and 246 are respectively the same as plates and 156i in the previous embodiment, like reference numerals have been used to designate like parts.

As shown, the annular groove 184 in stator 44 registers with outlet port 234, and the annular groove in port plate 246 registers with inlet port 232, thus providing for supply and exhaust of system fluid with respect to rotor chambers 62. Operation of the rotor, stator, valve plate, and port plate parts is the same as that previously described.

In this embodiment, however, value plate 244 is coupled to rotor 56 a modified assembly 250 comprising a short coupling member 252 and a sleeve 254. Sleeve 254 axially aligns with and is fixed to valve plate 244 by set screws 256. From valve plate 244, sleeve 254 extends freely through a central aperture 258` provided in port plate 246 and into a central axially open recess 260 formed coaxially in cover plate 236.

Coupling member 252 is formed at one end with a knuckle 262 extending into rotor 56 and at its opposite end with a knuckle 264 extending into sleeve 254. Segmental spherical splines 266 axially formed on knuckle 262 and engaging the internal splines on rotor 56 provide a universal rocking drive connection between rotor 56 and member 252. Similarly, member 252 is universally, rockably connected to sleeve 254 by segmental spherical splines 268 formed on knuckle 264 and engaging internal axial splines 270 formed in sleeve 254 adjacent cover plate 234. The end of knuckle 264 axially engages a thrust bearing comprising a -ball 272 seated in a socket 274. Socket 274 is formed in cover plate 234 at the end of recess 260.

In the assembly of the motor parts shown in FIGURES 15 and 16, cover plate 234, according to this invention, is drawn up just enough to allow a clearance A of about 0.015 inch between axially opposed faces of plates 234 and 246. By allowing this clearance, valve plate 244 and rotor S6 are permitted to rotate freely without grabbing or binding against their axially adjacent stationary surfaces when the motor is started. After startup, system fluid, which is usually oil, is fed, under pressure, through valve plate bores 200 (FIGURE 17) as previously explained, and, owing to the relatively loose axial fit of the valve plate 244 between port plate 150 and stator 44, this pressurized oil is uniformly distributed in friction reducing films over opposite sides of the valve plate. Provision of clearance A between cover plate 236 and port plate 246 eliminates the need for finishing the mating motor parts with very close tolerances to reduce manufacturing costs and to allow the motor parts to expand over a wide temperature range without causing objectionable friction or binding.

To keep plates 102, 244 and 246, stator 44 and rotor S6 from rocking as a result of providing for clearance A, system Huid under pressure is admitted to clearance A through a passageway arrangement comprising a straight axial passage 276 formed in housing 222 and intersected by two axially spaced radial passages 278 and 280. Passage 278 radially aligns with the interface between cover plate 236 and port plate 246. Plates 236 and 246, for permitting uid to enter clearance A, are respectively provided with chamfers 282 (FIGURE l) and 284 (FIGURES and 20) along their adjacent edges. Chamfers 282 and 284 form a V-shaped groove into which system oil under pressure enters from passage 278, wedging plates 234 and 246 apart and distributing uniformly in clearance A.

With continued reference to FIGURE 15, .passage 280 radially aligns with an annular outwardly opening at bottomed groove 286 (FIGURES l5 and 18) formed in the periphery of the valve plate 244 about midway between the opposite sides thereof. Intersecting groove 286 are three equiangularly spaced apart, axially extending, V-Shaped grooves 288 (FIGURE 17) notched into the periphery of plate 244. Thus, oil between plates 244 and 246 and between plate 244 and stator 44 flows serially through grooves 288 and 286 and passages 284i, 276 and 278 into clearance A.

The fluid flow areas conveying syst-em fluid to clearance A through passages 276, 278 and 280 are so related as to place about one-half of the system pressure in this clearance. In addition to preventing the motor parts in cylinder space 226 from rocking, the pressure of system fluid exerted in clearance A, in firmly urging valve plate 244 axially against the side faces of stator 44 and rotor 56, reduces leakage of pressurized uid from operating chambers 62.

With reference now to FIGURES 15 and 19, port plate 246 is provided with nine axially extending through bores 290 spaced equiangularly apart along a common circumference. Bores 290 are so arranged as to register with valve plate ports 174, of which there are also nine, when ports 174 contain full system pressure. This equalizes the pressure axially on opposite sides of port plate 246 to maintain a balanced condition and to prevent plate 246 from being rocked.

As shown in FIGURES 15 and 16, the end of each bore 290 adjacent to cover plate 234 is surrounded by a spacer and O-ring assembly 292. Assembly 292 cornprises a flat-sided, annular brass spacer 294 partially received in a straight-sided, flat-bottomed, axially open annular groove 296 formed in cover plate 234. Compressed between spacer 294 and the bottom of groove 296 is an O-ring 298 which resiliently urges spacer 294 into engagement with port plate 246.

Similarly, a spacer and O-ring assembly 380 coaxially surrounding recess 268 comprises a flat-sided annular brass spacer 302 and an O-ring 306, Spacer 302 is partially received in a flat-bottomed annular groove 304 formed in cover plate 236, and O-ring 306 is axially compressed `between the bottom of groove 304 and spacer 382. By tightening screws 238, spacers 294 and 382 are biased axially outwardly by O-rings 298 and 386 to axially urge port plate 246 against valve plate 244, thus pressing plate 244 more firmly against stator 44, and stator 44 more firmly against wear plate 102. As a result, assemblies 292 and 300 assist in maintaining clearance A and in preventing plates 244 and 246 and stator 44 from rocking.

With continuing reference to FIGURE 15, adjacent ends of coupling member 252 and -drive link 66 in rotor 56 are respectively provided with axially open. recesses 318 and 312 in which a thrust bearing comprising a -ball 314 is seated. Link 66 extends through the open end of housing part 224 opposite from cover plate 236 and into a tubular drive shaft 316. Intermediate its ends, shaft 316 is provided with an internal axially splined section 318 engaging the spherical splines 78 on knuckle 72. This establishes a universal rocking connection for trans mitting rotation of rotor 56 to shaft 316.

As shown in FIGURE l5, the end of knuckle 72 is recessed to matingly engage a thrust bearing comprising a ball 326 which is seated on a suitable spring 322. Spring 322 is received in an axially open blind bore 324 coaxially formed in a cylindrical lplug 326 which is slidably ,mounted in the outer end of shaft 316. A groovedseated O-ring 328 carried by plug 326 is radially compressed against the internal periphery of shaft 316 to prevent leakage of fluid through the shaft interior. Spring 322, as shown in FIGURE 15, biases ball 320 into snug engagement with the end of link 66 and axially urges plug 326 into abutment with an abutment comprising a split retainer ring 336 seated in an annular inwardly opening groove formed in shaft 316.

The inner end of shaft 316 projecting into the end of housing part 224 opposite from cover plate 236 is rotatably received in a housing bore section 334 of reduced diameter. A flat bottomed, annular groove 336 formed in housing part 224 and opening inwardly into bore section 334 radially adjacent the inner end of shaft 316 seats a resilient O-ring 338. O-ring 338 is compressed between the bottom wall of groove 336 and a slipper type annular seal 348 which is partially received in groove 336. Seal 348 is resiliently urged by O-ring 338 into fluid tight engagement with the periphery of shaft 316 to prevent fluid leakage between the opposed shaft and housing surfaces in bore section 334.

With continued reference to FIGURE 15, shaft 316 is shown to be journalled at its opposite ends in conventional anti-friction ball bearing assemblies 342 and 344. The outer race of bearing assembly 342 is seated on a smooth internal cylindrical surface 346 formed in housing part 244.

Axially between bearing assemblies 342 and 344, shaft 316 carries a pair of side-by-side, axially aligned, sprocket wheels 348 and 350 exteriorly of housing part 224. Wheels 348 and 350 respectively have abutting hubs 352 and 354 non-rotatably fixed to shaft 316 by a key and groove assembly 356. Wheels 348 and 350 are adapted to engage a chain drive (not shown) for driving a mechanism (not shown).

As seen from FIGURE 15, bearing assembly 342 is 1 1 axially retained in place between wheel hub 352 and a split retainer ring 358 seated in an annular groove formed in shaft 316. Similarly, bearing assembly 344 is axially retained in place between wheel hub 354 and a split retainer ring 360 seated in an annular groove formed in shaft 316 at its end remote from housing part 224.

With continued reference to FIGURE 15, assembly 344 mounts a bearing housing 362 and a bearing-cap 364. CapV 364 and housing 362 are fixed together as by cap screws 366 and are respectively provided with axially aligned, smooth, internal cylindrical surfaces 368 and 370 seated on the outer race of bearing assembly 344. Opposed, annular, radial shoulders 372 and 374 respectively formed integral with housing 362 and cap 364 engage opposite sides of the outer race of bearing assembly 344 so that cap 364 and housing 362 clamp as a unit onto assembly 344 by tightening screws 366.

As shown, cap 364 defines a lubricant chamber 376 for bearing assembly 344 at the end of shaft 316. To introduce lubricant into chamber 376 a standard grease fitting 378 is threaded into a through bore 380 provided in cap 364.

In both of the motor constructions illustrated in FIG- URES l14 and in FIGURES 16-20, it will be observed that a direct 1:1 ratio drive is provided between rotor 56 and the motor power output element. In comparison, the motor construction illustrated in FIGURES 21-23 contains a planetary gear reduction drive train to be presently described in detail.

In the embodiment of FIGURES 21-23, wherein like reference numerals are used to designate like parts, a modified housing assembly 386 comprises a hollow generally cylindrical housing part 388 which is axially open at both ends and which has an integral radial mounting flange 390 for rigidly securing the motor on a frame or other structure. Housing part 388 is diametrically enlarged at one end to provide a motor operating cylinder space 392 which is delimited by a smooth internal cylindrical wall surface 394.

As shown in FIGURE 21, cylinder space 392 is enclosed at its outer end by a cover plate 396 which is detachably fixed to the enlarged end of part 388 by a plurality of circumferentially spaced apart cap screws 400. An annular locating extension 402 formed integral with cover plate 396 slidably extends into cylinder space 392 and is undercut to provide an annular seat for a resilient O-ring 404. O-ring 404 is radially compressed against cylinder surface 394 to provide a fluid tight seal.

Mounted in cylinder space 392 in the same manner as described in the previous embodiments are stator 44, rotor 56, wear plate 102, valve plate 244, port plate 246 and coupling assembly 250. To admit and exhaust system lluid, cover plate 396 is formed with radially extending inlet and outlet motor operating ports 406 (FIGURE 22) and 408 (FIGURE 21) respectively. Ports 406 and 408 are enlarged at their outer ends to respectively receive system lluid supply and return conduits (not shown). The longitudinal axes of ports 406 and 408 are angularly spaced apart in a common plane.

With continued reference to FIGURE 22, a liuid passage 410 formed in cover plate 398 communicates at one end with inlet port 406 and registers at its opposite ends with fluid inlet chamber 412 formed in housing part 388. Similarly, outlet port 408 communicates with internal passage 414 (FIGURE 21) provided in cover plate 396. Remote from port 408, passage 414 registers with a fluid exhaust chamber 416 which is angularly spaced from inlet chamber 412.

With continued reference to FIGURES 21 and 22, the annular chamber 171 of port plate 246 is in uninterrupted fluid communication with inlet chamber 412 through a radial housing passage 418. Stator chamber 182 is in fluid communication with exhaust chamber 416 through a radial housing passage 419. Plate 246 is non-rotatably secured to cover plate 398 `by a cylindrical pin 420 having aaaaeaa its opposite ends slidably received in axially aligned, laterally offset blind bores 422 and 424 respectively formed in cover plate 396 and port plate 246-.

With continued reference to FIGURE 21, drive link 66, which is universally rockably connected at one end to r-otor 56 as previously described, extends forwardly through the open end of housing part 388 opposite from cover plate 398. Knuckle 72 projects into an axially open recess 428 formed in the end of a stub shaft 430. Recess 428 is internally splined at 432 to universally rockably engage splines '78 on knuckle 72, permitting rotor 56 to be displaced in its orbital path and transmitting the rotor movement to rotate shaft 430. The end of knuckle 72, as shown in FIGURE 2l, has an arcuate recess surface 434 bearing against a thrust bearing comprising -a ball 436 seated in a socket 438 which is provided at the inner end of recess 428.

With continued reference to FIGURE 2l, shaft 430 is journalled at opposite ends in axially aligned bushings 440 and 442. vBushing 440 is seated on a smooth internal cylindrical surface 444 formed in a plant gear carrier 446 comprising an elongated annular housing member having internal and external stepped diametrical sections as shown. An annular inwardly opening, flat-bottomed groove 448 formed in bushing 440 seats a resilient O-ring 450 which is radially compressed between the groove bottom and an annular, slipper type seal 452. O-ring 450 resiliently urges seal 452 into liuid tight engagement with the external periphery of shaft 430 for preventing fluid leakage through the interior of carrier 446.

As shown in FIGURE 21, Ihousing part 388 terminates in a reduced diametered end section 453 slidably receiving carrier 446. Axially adjacent to end section 453, housing part 388 and carrier cooperate to provide threaded sockets 454. Threaded into sockets 454 are set screws 455 to rigidly secure carrier 446 to housing part 388. A groove seated O-ring 456 carried by carrier 446 is radially compressed against the internal periphery of housing section 453 to provide a fluid tig-ht seal.

l)Vith continued reference to FIGURE 2l, bushing 442 is received with a mating press tit in a smooth cylindrically walled, axially opening recess 457 formed in a seal plate 453 ywhich is detachably fixed to carrier 446 by cap screws 459. Intermediate bushings 440' and 442, shaft 430 is integrally provided with a sun gear 460 forming a part of a planetary gear train now to be described.

Gear 460, as shown in FIGURES 21 and 23, constantly mesh with three equiangularly spaced apart planet gears 462, each of which is freely rotatably mounted by a bushing 463 on an axially extending journal pin 464. Each pin 464 coaxially extends into a blind bore 466 formed in carrier 446 and is axially retained in place between seal plate 458 and an annular shoulder 468 'formed at tie bottom of bore 466.

As shown in FIGURES 21 and 23, a sprocket wheel 470 is provided with an elongated hub 472 which is internally formed with a ring `gear 474 meshing with planet gears 462. External sprocket or gear teeth 476 formed on hub 472 are adapted to engage -a suitable drive for transmitting torque to a driven mechanism (not shown).

With continued reference to FIGURE 21, sprocket wheel 470 is rotatably mounted on housing part 338 and lcarrier 446 by axially spaced apart antif-riction 'bearing assemblies 478y and 480.

Bearing assembly 478 has its inner race seated on the smooth external periphery of housing section 453. The outer race of bearing assembly 478 is seated on a smooth cylindrical internal surface 482 on hub 472. Assembly 478 is axially retained in place fbetween an annular shoulder 484 formed on housing part 388 and an inwardly projecting yannular flat-sided rib 485 formed integral with hub 472 in radial alignment with gear teeth 476.

yBearing assembly 480 is axially retained between rib 485 and an annular axially extending shoulder 486 formed on carrier 446 exteriorly of housing part 388. The inner and outer races of assembly 480 are respectively seated on a smooth external cylindrical surface 488 formed on carrier 446 and a smooth internal cylindrical surface 490 formed on hub 472.

With the foregoing structure, it is clear that housing part 388, sprocket wheel 470', and seal plate 458 cooperate to 1define a housing envelope for the internal motor parts. Hub 472 and carrier 446, as shown in FIGURE 2l, define an annular `lubricant chamber 492 into which lubricant is introduced through a threaded opening 494 formed in seal plate 458 below the axis of shaft 430. Chamber 492 is norm-ally filled with lubricant to the level of opening 494 which receives a threaded plug 495. Chamber 492 is sealed at axially opposite ends by oi'l seals 496 and 498. Seal 496 is radially clamped between the inner end of wheel `hub 472 adjacent bearing assembly 478 and `an intermediate cylindrical section 500 lon housing part 388. At the opposite end of chamber 492, oil seal 498 is radially clamped between seal plate 458 and wheel hub 472.

As a result, it is evident that the lubricant chamber 492 is fully sealed and is also isolated from the internal cha-rnber space containing system operating fluid for energizing the motor. This motor construction incorporating the planetary gear train is compact, permits ready Iaccess to internal parts, and promotes long and useful life of operating parts.

The invention may be embodied in other specific forms without depa-rting from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative `and not restrictive, the scope of the invention lbeing indicated by the appended claims rather than 'by the foregoing description, and all changes which come within the meaning and range 4of equivalency of the claims are therefo-re intended to be embraced therein.

What is claimed and desired to Ibe secured by United States Letters Patent is:

1. In a `rotary fluid motor, a housing enclosing a fluid operating space having `a fluid inlet opening adapted to be connected to a source of pressurized operating lluid and a iluid outlet opening, means in said space providing a plurality of expansible fluid :chambers and comprising interengaging stator and rotor elements, 3, member axially spaced from said stator and rotor elements in said space and having a plurality of inlet ports communicating with said inlet opening, a plurality of outlet ports formed in said stator element and communicating with said outlet opening, a ported valve plate non-rotatably coupled to said rotor and so disposed axially between said member and said stator element as to cyclically establish and block fluid communication between said cham-bers and said inlet and outlet ports for admitting and exhausting operating fluid to drive said rotor, said housing having an axial access opening at one end of said space for permitting introduction and removal of said rotor and stator elements and said member, a cover detachably secured to said housing and extending over said opening, and surface means in said housing and coacting with said cover to axially conne said rotor and stator elements and said member in place.

2. In a rotary fluid motor, a housing enclosing a cylindrical fluid operating space having a iluid inlet opening adapted to be connected to a source of pressurized operating iluid and a fluid outlet opening spaced axially from said inlet opening along the longitudinal axis of said :cylindrical space, means in said space providing a plurality of circumferentially disposed expansible iluid operating chambers and comprising lobed inter-engaging rotor and stator elements arranged one within the other, said stator element having more lobes than those on said rotor element and being coaxially and non-rotatably disposed in said space, driven means `rotatably mounting said rotor for eccentric orbital movement about the stator axis, a series of equiangularly spaced apart axially extending iluid exhaust passages formed in said stator and communicating with said outlet opening, a non-rotatably mounted member coaxially spaced from said rotor and stator elements in said space and having a series of equiangularly spaced apart fluid inlet passages in fluid communication with said inlet opening, and a valve plate non-rotatably coupled to said rotor for rotation about said stator axis and disposed axially between said member and said stator, said valve plate having a series of axially extending equiangularly spaced apart through ports so arranged as to cyclically establish and block fluid communication between said chambers and said inlet and outlet passages for admitting and exhausting operating fluid to drive said rotor.

3. In a rotary fluid motor, a housing providing a fluid operating space having a fluid inlet opening adapted to be connected to a source of pressurized operating iluid and a fluid outlet port, means in said space providing for a plurality of successively expansible and contr'actible fluid operating chambers and comprising lobed intermeshing stator and rotor elements, a member axially spaced from said rotor and stator elements, said member being mounted in lsaid space `for limited axial displacement and having a plurality of inlet ports in fluid communication with said inlet opening, a ported valve plate disposed axially between said member and said rotor and stator elements and being rotatable to cyclically establish and block fluid communication -between said chambers and said inlet and outlet ports for admitting and exhausting operating fluid to drive said rotor, stationary surface means disposed with a predetermined :clearance on the side of said member opposite from said valve plate and delimiting said space, and means for introducing motor operating fluid under pressure into said clearance to axially urge said member into engagement with said valve plate for non-rockably retaining said valve plate axially between said stator element and said member.

4. The rotary fluid motor defined in claim 3 wherein said means introducing fluid into said clearance comprises a passage formed in said housing and communicating at one end with said clearance, groove means formed in said valve plate and communicating with the other end of said passage, said groove means being in iluid communication with said valve plate ports through the clearance at least on one side of said valve plate.

5. The rotary fluid motor defined in claim 3 comprising a plurality of axial through passages formed in said member in spaced relation to said inlet ports and arranged to cyclically register with said valve plate ports to transmit operating uid under pressure to the opposite side of said member.

6. The rotary fluid motor `delined in claim 3 comprising spacer means resiliently urging said member and said stationary surface means axially apart.

7. The rotary iluid motor defined in claim 6 wherein said spacer means comprises a rigid annulus mounted in an axially inwardly opening annular groove formed in said surface means, and a resilient O-ring radially compressed between the bottom of said groove and said annulus and urging said annulus partially out of said groove and into abutment with said member.

8. The rotary iluid motor dened in claim 7 wherein said surface means comprises a cover plate, and wherein means are provided for detachably xingsaid cover plate to said housing.

9. In .a rotary lluid motor, a housing enclosing a luid operating space having a lluid inlet opening adapted to be connected to a source of pressurized operating iluid and a fluid outlet opening, means in said space providing a plurality of expansible fluid chambers and comprising interengaging stator and rotor elements, a member axially spaced from said stator and rotor elements in said space and having .a .plurality of inlet ports communicating with said inlet opening, -a plurality of outlet ports formed in said stator element and communicating with said outlet opening, a ported valve plate non-rotatably coupled to said rotor and so disposed axially 'between said member `and said stator element as to cyclically establish and block fluid communication between said chamber-s and said inlet and outlet ports for admitting and exhausting operating uid to drive said rotor, and means for balancing uid pressure on axially opposite sides of said valve plate without interference with the admission and exhaust of fluid with respect to said chambers.

10. The rotary fluid motor dened in claim 9, wherein said balancing means comprises a plurality of through passages formed in said valve .plate with each of said through passages being alternately registerable with said intake and outlet passages.

Re. 25,291 12/1962 Charlson 91-56 2/1962 Charlson 91-56 X- 1 6 1/1879 Nash 91-56X 8/1921 Feuerheerd 103-130 5/1941 Thomas et al. 91-56 8/1956 Krozal 91-56 2/1959 Patin 91-56 X 6/1961 Charlson 91-81 X 4/1963 Dettlof et al 103-130 7/1964 Wilkinson 103-130 X FOREIGN PATENTS 1/ 1962 Switzerland.

MARTIN P. SCHWADRON, Primary Examiner.

A. s. ROSEN, P. T. COBRIN, Assistant Examiners.

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Classifications
U.S. Classification418/61.3, 418/190
International ClassificationF04C2/10, F04C2/00
Cooperative ClassificationF04C2/105, F04C2/104
European ClassificationF04C2/10E4, F04C2/10E2