US3846055A - Abutment rotary hydraulic motor or pump - Google Patents

Abstract

A rotary abutment type hydraulic motor is disclosed comprising a housing having a rotor chamber and a pair of abutment valve chambers intersecting the rotor chamber. A rotor having at least three lobes is disposed in the rotor chamber, and a two lobed stator is provided in each of the abutment valve chambers. The abutment valve axes are circumferentially spaced apart one-half the angular spacing between adjacent rotor lobes. A unique sealing arrangement is provided between the rotor lobes and rotor chamber wherein sealing pins carried by the rotor lobes are hydraulically displaced radially outwardly to sealingly engage the inner surface of the rotor chamber during motor operation. A unique abutment valve lobe rotor hub sealing arrangement is also provided which is defined by a metal plate extending between adjacent rotor lobes and hydraulically displaceable metal pins disposed beneath the plate in recesses in the rotor hub. Hydraulic fluid under pressure biases the pins outwardly against the plate to bias the plate into sealing engagement with the abutment valve lobes during interengagement therebetween. Opposite ends of the abutment valve shafts are provided with a floating bearing and seal arrangement which is responsive to hydraulic fluid under pressure to seal the shaft ends against leakage of hydraulic fluid thereacross.

Description

United States Patent [191 Brundage Nov.5,1974

[76] Inventor: Robert Wesley Brundage, 2809 Wakonda Dr., St. Louis, Mo. 63121 [22] Filed: July 31, 1972 [21] Appl. No.: 276,662

[52] U.S. Cl 418/124, 418/139, 418/196, 418/227, 308/26, 308/36.1

[51] Int. Cl. F0lc 1/08, F01c 19/00, F03c 3/00 [58] Field of Search ..418/112,113,123,124, 418/139, 196, 227; 277/94; 308/26, 36.1, 187.1

[56] References Cited 1 UNITED STATES PATENTS 927,781 8/1909 Farrow 418/124 2,472,031 5/1949 Wichorek 418/77 2,487,732 11/1949 1 Schanzlin 418/189 2,690,164 9/1954 418/196 2,710,581 6/1955 308/36.1 2,751,846 6/1956 418/196 2,790,394 4/1957 418/1 13 3,123,012 3/1964 418/196 3,416,458 12/1968 418/196 3,567,350 3/1971 Niemiec 418/112 FOREIGN PATENTS OR APPLICATIONS 1,072,674 3/1954 France 418/196 153,910 3/1956 Sweden 308/36.1 469,894 b 4/1969 Switzerland 418/ 196 Primary Examiner-lohn J. Vrablik [57] ABSTRACT A rotary abutment type hydraulic motor is disclosed comprising a housing having a rotor chamber and a pair of abutment valve chambers intersecting the rotor chamber. A rotor having at least three lobes is disposed in the rotor chamber, and a two lobed stator is provided in each of theabutment valve chambers. The abutment valve axes are circumferentially spaced apart one-half the angular spacing between adjacent rotor-lobes. A unique sealing arrangement is provided between the rotor lobes and rotor chamber wherein sealing pins carried by the rotor lobes are hydraulically displaced radially outwardly to sealingly engage the inner surface of the rotor chamber during motor operation. A unique abutment valve lobe rotor hub sealing arrangement is also provided which is defined by a metal plate extending between adjacent rotor lobes and hydraulically displaceable metal pins disposed beneath the plate in recesses in the rotor hub. Hydraulic fluid under pressure biases the pins outwardly against the plate to bias the plate into sealing engagement with the abutment valve lobes during interen'gagement therebetween. Opposite ends of the abutment valve shafts are provided with a floating bearing and seal arrangement which is responsive to hydraulic fluid under pressure to seal the shaft ends against leakage of hydraulic fluid thereacross.

18 Claims, 10 Drawing Figures PATENTEDNUV 5l974 sum 10F 4 NOV 5am I 3; PATENTED E a m 846 055 PATENTEE van? 5 1914 3. 846; 055

sum 3 a? a ABUTMENT ROTARY HYDRAULIC MOTOR R PUMP BACKGROUND In the art of positive displacement hydraulic motors of the foregoing character, the motor housing is provided with a cylindrical rotor chamber and one or more abutment valve chambers which are cylindrical and intersect the rotor chamber so as to be in fluid communication therewith. The housing is provided with fluid inlet and outlet passages opening into the rotor chamber at locations spaced about the periphery thereof. Hydraulic fluid under pressure enters the rotor chamber through the inlet passage, imparts rotation to a lobed rotor and is discharged through the outlet passage. A lobed sealing abutment value is disposed in each of the one or more abutment valve chambers in the housing and is adapted to sealingly engage the rotor during rotation thereof to prevent the flow of hydraulic fluid under pressure from the inlet passage to the outlet passage in a direction opposite to the direction of rotation of the rotor.

Among the most difficult problems encountered in connection with the construction and operation of hydraulic motors of the foregoing character is the fact that various fluid leakage paths exist between the rotor and abutment value components and between these components and the motor housing whereby a percentage of the hydraulic fluid under pressure entering the motor through the inlet passage is ineffective as a working fluid for driving the rotor. It will be appreciated that such losses of working fluid reduce the efficiency of the motor by reducing the speed at which the output shaftcan be driven. Such leakage paths exist between the lobe or lobes of the rotor and the inner surface of the rotor chamber, between the interengaging surfaces of the rotor and abutment valve components, and in areas between the supporting shafts of these components and supporting walls of the motor housing.

Other problems encountered with regard to such hydraulic motors include that of achieving a desired operating efficiency and torque output while maintaining the cost and physical size of the hydraulic motor at a minimum. Efforts heretofore to reduce the leakage problem and increase efflciency while providing a desired torque output have resulted in motor structures which are undesirably large and/or expensive to manufacture as the result of the number of component parts required and/or the precise tolerances and close clearances with respect to the parts. In addition to the foregoing disadvantages, highly precisioned parts cause hot stalls due to unequal expansion of the parts when heated. Also, the motor units can not tolerate overhung loads and the distortion of parts resulting therefrom. It will be appreciated too that the number of parts and the precision thereof increase maintenance costs encountered when replacement of parts is required due to wear thereof.

Yet another problem encountered in hydraulic motors of the foregoing character is that of achieving reasonably smooth and non-pulsing rotation of the fluid displacement component of the motor. In this respect, pockets of hydrualic fluid under pressure are transferred by the displacement component from the high pressure inlet to the low pressure outlet and, in certain motors heretofore provided, such transfer results in a pulsing of the output shaft through the displacement component. Such pulsing is caused by the sudden release of hydraulic fluid under pressure from the moving hydraulic pockets as each of the latter moves into communication with the outlet passage of the motor. Efforts heretofore to overcome or reduce the pulsing problem result in an undesirably large and/or relatively expensive device due to the design and/or number and arrangement of component parts thereof.

Furthermore, hydraulic motors have been provided heretofore which are intended primarily to provide a reasonably small motor in physical dimension. The results of previous efforts in this direction, however, have not been as successful as desired for many reasons including the fact that the designs result in undesirably small inlet and outlet fluid passageways, whereby the displacement capacity of the motor is reduced as well as the output torque which can be developed.

THE INVENTION in accordance with the present invention the foregoing disadvantages and others of hydraulic motors heretofore known are advantageously overcome.

in accordance with one important aspect of the present invention, a rotary abutment hydraulic motor is provided including a rotor and a pair of abutment valves disposed within corresponding rotor and abutment valve chambers in the motor housing. Each abutment valve has two lobes and the abutment valves are rotatable about corresponding longitudinal axes which are circumferentially spaced apart by an angle equal to one-half the angular spacing between adjacent rotor lobes. This relationship, which will be described in greater detail hereinafter, advantageously provides for the areas of the fluid ports to be larger than would otherwise be possible without endangering the structural integrity of components of the motor. In the preferred embodiment, the rotor has three lobes and the abutment valves each have two lobes, which combination of lobes is believed novel and gives improved results. it will be appreciated that the foregoing angular relationship provides, in the preferred embodiment for the abutment valves to be rotatable about axes which are circumferentially spaced apart 60. While the three lobed rotor and two, two lobed abutment valve arrangement is preferred for a hydraulic motor, a four lobed rotor and two, two lobed abutment valve arrangement is preferred for a pump. The latter arrangement provides, according to the above angular relationship, for the abutment valves to be rotatable about axes circumferentially spaced apart 45 whereby additional fluid porting area is available within te fluid displacement chamber of the device.

In accordance with another important aspect of the present invention, a sealing arrangement between the rotor lobes and the outer walls of the rotor chamber is provide comprised of fluid actuated sealing elements on the radially outer ends of the rotor lobes engagable with the walls of the rotor chamber during rotation.

The hydraulically actuated seal arrangement in combination with the outlet passage operates in the manner of a valve when the corresponding lobe reaches the outlet passage, whereby hydraulic fluid under pressure in the pocket behind the lobe is gradually released for flow through the outlet passage as opposed to being suddenly released upon movement of the fluid pocket into communication with the outlet passage. The gradual release avoids the existance of a sudden pressure drop in the fluid pocket which would result in a pulsing movement being imparted to the rotor. The use per se of a hydraulically actuated sealing element on the radially outer end of a rotor lobe is not new and is disclosed in conjunction with an oscillating hydraulic motor rotor lobe in my U.S. Pat. No. 3,418,886 issued Dec. 31, 1968. The sealing arrangement of the present invention, however, distinguishes both structurally and functionally from my earlier arrangement as will become apparent from the description hereinafter of a preferred embodiment of the present invention.

In accordance with yet another important aspect of the present invention a unique sealing arrangement is provided between the hub portions of the rotor between adjacent lobes thereof and the lobes of the abutment ,valve members which provides a more effective seal against fluid leakage around the hub area than heretofore possible. The sealing arrangement includes sealing elements between adjacent rotor lobes which are hydraulically biased into engagement with the abutment valve lobes during rotation of the rotor and abutment valve components.

In accordance with yet a further aspect of the present invention, a unique bearing and seal arrangement is provided between components of the housing and shaft portions of the abutment valve members to effectively reduce leakage of hydraulic fluid across the areas between the abutment valve shafts and housing. The latter sealing arrangement includes floating bearing and sealing components associated with the abutment valve shafts and motor housing openings therefor. The bearings are axially biased into sealing engagement with cooperable housing portions during operation of the motor and in response to hydraulic pressure thereagainst and, at times, the .force of the corresponding abutment value thereagainst. This sealing arrangement effectively minimizes fluid leakage along the abutment valve shafts and, moreover, advantageously lends to the economical production and maintenance of the motor by reducing the degree of accuracy required in the forming and machining of the components of the assembly.

It will be appreciated, of course, that a rotary abutment type hydraulic motor of the character described can be operated as a pump by driving the rotor shaft to transfer hydraulic fluid from the inlet to the outlet passage of the rotor chamber.

OBJECTS Accordingly, it is an outstanding object of the present invention to provide an improved rotary abutment type hydraulic device comprised of a minimum number of component parts organized to provide a compact unit which is simple to construct, inexpensive to manufacture, extremely efficient in operation and durable under conditions of prolonged use.

A further object of the present invention is the provision of a rotary abutment type hydraulic motor or pump which is compact in size and comprised of component parts structured and operatively interrelated for the device to have a higher fluid displacement capacity and torque output than heretofore possible in a device of a corresponding physical size.

Still another object of the present invention is the provision of a hydraulic motor of the foregoing character having rotor and abutment valve members structured and operatively interrelated in a manner which lends to providing a high torque output and a high volume of fluid displacement in a minimum amount of internal chamber space.

Still another object of the present invention is the provision of a hydraulic motor or pump having an internal sealing arrangement by which pulsing of the fluid displacement component of the motor or pump during operation thereof is minimized.

A further object is the provision of a rotary abutment type hydraulic motor or pump having a three or more lobed rotor and a pair of two lobed abutment valves and wherein the abutment valves are rotatable about axes circumferentially spaced apart by an angle equal to one-half the angle between adjacent lobes of the rotors.

Still another object is the provision of a rotary abutment type hydraulic motor or pump having a three lobed rotor cooperatively associated with a pair of two lobed abutment valves whereby torque output, fluid displacement, and operating efficiency are maximized for a given internal chamber area.

Still a further object of the present ivnention is the provision of a hydraulic motor or pump of the foregoing character in which fluid leakage internally of the motor or pump during operation thereof is minimized.

Yet another object is the provision of a hydraulic motor or pump having hydraulically actuated seal arrangements which more effectively seal the spaces between components of the motor or pump than heretofore possible, whereby fluid leakage internally of the device during operation thereof is minimized.

Still another object is the provision of a hydraulic motor or pump having a lobed rotor including a unique seal arrangement comprised of hydraulically actuated sealing pins for sealing between a lobe of the rotor and the rotor chamber.

Another object is the provision of a hydraulic motor or pump of the foregoing character wherein the rotor lobe-rotor chamber seal arrangement functions to gradually intercommunicate high and low fluid pressure sides of the rotor lobes as the lobes approach the fluid outlet passages.

Yet another object is the provision of a hydraulic motor or pump having lobed rotor and abutment valve components and including seal plates between the rotor lobes which plates are hydraulically biased for sealing engagement with the abutment valve lobes to prevent fluid leakage therebetween.

Still another object is the provision of a hydraulic motor or pump having rotor anda b utment valve components and including a unique sealing arrangement between a shaft portion of the abutment valve and an opening in a wall of the housing in which the shaft portion is disposed, and which includes a floating bearing and sealing assembly.

PREFERRED EMBODIMENT The foregoing objects and others will in part be obvious and in part more fully pointed out hereinafter in conjunction with the accompanying description of the drawings which illustrate a preferred embodiment of the present invention and in which:

FIG. 1 is a perspective view of a hydraulic motor made in accordance with the present invention;

FIG. 2 is an elevation view, in section, of the hydraulic motor, the view being along line 22 in FIG. 1;

FIG. 3 is a sectional elevation view of the motor, the section being along line 3-3 in FIG. 2;

FIG. 4 is a plan view of the motor, in section, the section being along line 44 in FIG. 2;

FIG. 5 is a detail view, partially in section, of the bearing and seal arrangement between a abutment valve shaft and housing wall;

FIG. 6 is an enlarged detail view, in vertical section, of a portion of the rotor of the motorand illustrating the rotor lobe and rotor chamber in sealed relationship;

FIG. 6A is an enlarged detail view in vertical section illustrating the rotor lobe and rotor chamber in unsealed relationship;

FIG. 6B is an enlarged detail view in vertical section illustrating the rotor lobe seal element in relationship to the fluid outlet passage;

FIG. 7 is an end view of the motor, partially in section, the section being taken along line 7-7 in FIG. 3

FIG. 8 is an enlarged detail view, in vertical section, illustrating the cooperative sealing relationship between the rotor hub and a an abutment valve; and

FIG. 9 is a schematic cross-sectional elevation view of a hydraulic pump made in accordance with the present invention.

HOUSING Referring now in greater detail to the drawings wherein the showings are for the purpose of illustrating a preferred embodiment of the invention only and not for the purpose of limiting the same, FIGS. 1-4 illustrate a hydraulic motor, comprised of a housing including axially outer metal housing members I2 and 14 and an intermediate metal housing member 16. Housing members 12 and 14 preferably, but not necessarily, are cast aluminum, and housing member 16 preferably is cast ductile iron. The housing members may be interconnected in any suitable manner and, preferably, are releasably interconnected by means of a plurality of headed studs 13. In the embodiment illustrated, for example studs 18 extend axially through corresponding openings in outer housing member 14 and inner housing member 16 and into threaded engagement with corresponding openings in outer housing member 12. Further, any suitable means may be provided for mounting the motor unit on a support member and, in this respect, in the embodiment illustrated housing member 14 is provided with integral mounting plate portions 20 each of which extends laterally outwardly from a corresponding side of the motor housing. Each mounting plate portion 20 is provided with a suitable opening 22 to facilitate mounting of the motor unit to a support member therefor.

A rotor chamber 24 and a pair of abutment valve chambers 26 and 28 are provided within the motor housing for the rotor and abutment valve components of the motor to be described more fully hereinafter. In the embodiment illustrated, intermediate housing member 16 is an annular component having an inner periphery contoured to provide for the rotor chamber to have a wall portion 30 having a radius of curvature symmetrical with respect to rotor chamber axis A. Wall portion 30 is circumferentially symmetrical with respect to a vertical line through axis A in FIG. 2 and extends circumferentially a total of approximately Rotor chamber 24 further includes wall portions 30a and 30b at opposite ends of portion 30, which portions 30a and 30b blend with the corresponding end of portion 30 and diverge with respect to axis A for the purpose set forth hereinafter. The inner periphery of housing member 16 is also contoured to provide a pair of cylindrical surfaces 32 and 34 defining the peripheral boundaries of abutment valve chambers 26 and 28, respectively. The axially opposite ends of the rotor and abutment valve chambers are defined by the corresponding inner surface faces 12a and 14a of housing members 12 and 14. The inner faces of housing members l2 and I4 radially outwardly of the rotor and abutment valve chambers are provided with corresponding recesses or grooves 36 in which rubber O-ring sealing elements 38 are disposed for sealing engagement with the corresponding opposed surface of housing member 16 when the housing members are interconnected. Preferably, recesses 36 follow the contour of cylindrical surfaces 30, 30a, 30b, 32 and 34 and are disposed as close to these surfaces as is practical in order to minimize the unsealed radial surface area between the rotor and abutment valve chambers and the sealing elements.

Abutment valve chambers 26 and 28 have respective longitudinal axes B and C each of which is parallel to and equally spaced from the longitudinal axis A of the rotor chamber. Further, in the embodiment illustrated, abutment valve chamber axes B and C are circumferentially spaced apart 60.

ROTOR A rotor member 40, preferably of powdered iron, is disposed in rotor chamber 24 for rotation about axis A and is keyed or otherwise mounted on a shaft 42 or rotation therewith. Rotor 40 preferably is of an axial length less than the axial thickness of housing member 16 by approximately 0.001 inch per inch of length, whereby a clearance space 41 ia provided between each end of the rotor and the corresponding surface of housing members 12 and 14. Shaft 42 preferably is of hardened steel and extends axially through chamber 24 and through corresponding shaft openings in housing members 12 and I4. Bearings 44 are provided between shaft 42 and the shaft openings in housing members 12 and 14 to support shaft 42 and thus rotor 40 for rotation about axis A. One end 46 of shaft 42 extends axially outwardly of housing member 14 to define an output shaft for the motor. A thrust bearing assembly 48 is disposed in a recess in the outer face of housing member 14 and surrounds shaft 42 to limit axial displacement thereof relative to the housing. In this respect, the inner race of bearing race of bearing assembly 48 is supported by shaft 46 and is positioned axially thereof by split retainer rings 50 disposed in corresponding peripheral recesses in the shaft. Bearing assembly 48 is removably retained in place by means of rings 50 and an end plate 52 mounted on the outer face of housing member 14 such as by threaded fasteners 54 tending through openings in plate 52 and into housing member 14. A seal assembly 56 surrounds shaft portion 46 and may, for example, be defined by an annular sealing component 58 biased radially inwardly for sealing engagement with shaft portion 46 by a coil spring 60 extending thereabout and in engagement therewith. Seal assembly 56 seals the motor against leakage of hydraulic fluid axially outwardly along shaft portion 46 at the corresponding end of the motor.

The end of shaft 42 opposite end 46 thereof terminates in a gear chamber 62 defined by a recess in the outer end face of housing member 12, which recess is closed by a suitable metal end plate 64 mounted on housing member 12 such as by means of threaded fasteners 66. The latter end of shaft 42 is provided with a gear 68 which is mounted on the shaft for rotation therewith in any suitable manner. In the embodiment illustrated, gear 68 is mounted on the shaft by means of a key 70, and axial displacement of gear 68 relative to the shaft is restrained by a pair of split retaining rings 72 having portions disposed in corresponding peripheral recesses in the shaft. The purpose and operation of gear 68 will be described more fully hereinafter.

ABUTMENT VALVES Abutment valve members 74 and 76 are disposed in abutment valve chambers 26 and 28, respectively. Abutment valves 74 and 76 are of identical construction and are similarly supported for rotation relative to the motor housing. In this respect, with reference to abutment valve 74 illustrated in FIG. 3 of the drawing, the abutment valve has a shaft portion 78, preferably of hardened steel, extending axially from one end thereof into a corresponding shaft recess 80 in housing member 14. A suitable bearing 82 is disposed between shaft portion 78 and the inner surface of recess 80 to support the corresponding end of the abutment valve for rotation relative to the housing. Further, shaft portion 78 includes a terminal shaft portion 84 extending axially from the outer end thereof and into a corresponding recess 86 extending axially from recess 80. Terminal shaft portion 84 is of a smaller diameter than shaft portion 78 and a bearing and sealing assembly 88 to be described more fully hereinafter is provided between shaft portions 78 and 84, the end face of recess 80 and the peripheral wall of recess 86. Similarly, abutment valve 74 is provided with a hardened steel shaft portion 90 extending axially from the opposite end thereof into a corresponding recess 92 in housing member 12. A bearing 94 similar to bearing 82 is provided between shaft portion 90 and recess 92 to support the shaft portion for rotation relative to the motor housing. Shaft portion 90 has a terminal shaft portion 96 extending axially outwardly therefrom and through a housing wall portion 98 into gear chamber 62. Shaft portion 96 is of a diameter corresponding to that of shaft portion 84 and is also provided with a seal assembly 88 which, in this instance, is disposed between shaft portions 90 and 96, the inner face of housing wall 98 and the inner surface of the opening in wall 98 through which shaft portion 96 extends. The outer end of shaft portion 96 is provided with a gear 100 which is keyed or otherwise mounted on shaft portion 96 to prevent relative rotation therebetween. Further, gear 100 is axially positioned relative to the shaft portion by a pair of split rings 102 having inner portions associated with peripheral grooves in the shaft portion in a well known manner. The teeth of gear are disposed in meshing engagement with the teeth of gear 68 of the rotor shaft as can readily be seen in FIGS. 3 and 7. Likewise, the corresponding gear 100 mounted on the corresponding terminal shaft portion of abutment valve 76 is disposed in meshing engagement with rotor shaft gear 68.

The assembly abutment valve comprised of the body portion of the abutment valve disposed in the abutment valve chamber and the shaft portions extending from axially opposite ends thereof, may be an integral unit, but preferably, the shaft portions including the terminal shaft portions are produced as integral components separate from the abutment valve body and are suitably interconnected with the corresponding end of the abutment valve body such as by brazing. The abutment valve body preferably is of hardened steel.

ROTOR-ABUTMENT VALVE RELATIONSHIP Referring now in greater detail to the structures and the cooperative operational interrelationship between the rotor and abutment valves components, it will be seen in FIG. 2 that rotor 40 is comprised of a cylindrical hub portion and three radially extending rotor lobes 112a, ll2b and 1120 equally spaced apart about the periphery of the hub portion. The rotor lobes extend radially from the hub portion and terminate in corresponding outer faces 114 generally parallel to and slightly spaced inwardly of inner surface 30 of the rotor chamber, as best seen in FIGS. 2 and 6. Further, the circumferentially opposite sides of each rotor converge in the direction from the rotor hub toward outer faces 114.

The body portions of abutment valves 74 and 76 are of identical structure and, accordingly, it is only necessary to describe the structure of one of the abutment valve bodies in detail. In this respect, with reference to FIG. 2 it will be seen that abutment valve 76 includes an opposed pair of lobes 116a and 1161) and an opposed pair of recesses 118. Recesses 118 preferably are cylindrical in cross section and are of an axial length slightly greater than the axial thickness of housing member 16. Further, the recesses have a radius providing a depth relative to axis C which will provide for rotor lobes 112a, ll2b and 112C to pass therethrough free of interengagement therewith during relative rotation of the rotor and abutment valves as set forth more fully hereinafter. The portion of the abutment valve body between recesses 118 defines the pair of diametrically opposed abutment valve lobes 116a and 1161;. Each of the abutment valve lobes has a cylindrical outer surface 120 cooperatively engagable with the rotor hub in the area thereof between peripherally adjacent rotor lobes 112 in the manner described hereinafter. Further, the cylindrical outer surfaces 120 of the abutment valve lobes are adapted to sealingly engage cylindrical surface 34 of the abutment valves chamber during rotation of the abutment valve.

The three lobe rotor and two lobe abutment valve arrangement advantageously provides for applicants device to be of compact construction, for the components thereof to be structurally sound, and for the device when operated as a hydraulic motor to have a high torque output and maximum volumetric fluid displacement. In this respect, with reference in particular to FIG. 2, the structure and arrangement of these components facilitates providing the rotor chamber with fluid inlet and outlet passages 122 and 124, respectively, having a larger area then would be otherwise possible, whereby the maximum volume of fluid flow through the device is achieved. The area of the inlet and outlet openings in a device of this character is determined in part by the circumferential space available in the rotor chamber which in turn is determined in part by the diameter and circumferential positioning of the abutment valves. The size of the abutment valves in turn is determined in part by strength requirements therefor to assure against structural failure. By employing a rotor having three lobes and a pair of abutment valves each having two lobes, in accordance with the present invention, the abutment valves are structurally sound and minimize the circumferential space relative to the rotor axis which is necessary to house the abutment valve components. More particularly, the abutment valve components are each two-thirds the diameter of the rotor hub and are physically located approximately 60 apart from one another, the limitation to closeness being that they must be separated by approximately one-half the angle between two adjacent rotor lobes.

In the embodiment illustrated, as mentioned hereinabove, the abutment valve axes B and C are advantageously circumferentially spaced apart 60. The provision of two two-lobed abutment valves so related physically within the housing increases the circumferential area available to define the rotor chamber within the housing. This in turn increases the size of the inlet and outlet openings which can be employed. In this respect, it will be appreciated that the three equally spaced lobes of the rotor have radial axes circumferentially spaced apart 120 relative to one another. This distance between the rotor lobe axes determines the circumferential distance which can exist between end 122a of inlet port 122 and end 124a of outlet portion 124 so that the fluid pocket defined between two circumferentially adjacent rotor lobes is closed to fluid flow through inlet 1122 an instant before the pocket moves into communication with outlet passage 24 for the fluid to flow from the pocket through the outlet. The circumferential distance between ends 122a and 12b of inlet passage 122 and ends 124a and 1241b of outlet passage 124 is limited only by the circumferential surface area available in housing member 12 through which the ports open between ends 122a and l24a and the point along the surface of housing member 12 at which the opposite port edge would intersect with the outer surface of the corresponding abutment valve. With the two abutment valves arrangement in which the abutment valve axes are spaced 60 from one another, as illustrated in FIG. 2, the inlet and outlet ports can have a circumferential extent between the circumferentially opposite ends thereof in excess of 60. The radial dimension of the inlet and outlet ports is limited only by the radial space existing between the hub portion of the rotor and the peripheral surface 30 of the rotor chamber. Accordingly, reasonably large port areas are achieved whereby a high volume of fluid displacement through the device is made possible. The displacement capabilities of the device are also enhanced by the three lobe two lobe concept in that the rotor lobes can project radially from the hub portion of the rotor to an extent which provides a maximum volume for the fluid pocket defined between circumferentially adjacent rotor lobes and the inner surface of the rotor chamber for given hub and abutment valve diameters.

OPERATION During operation of the hydraulic motor, hydraulic fluid under pressure enters the rotor chamber through inlet port 122 and imparts rotation to the rotor in a counter-clockwise direction as viewed in FIG. 2. Rotation of rotor 30 drives rotor gear 68, whereby abutment valve gears are driven simultaneously and in a direction opposite that of the direction of rotation of the rotor, whereby abutment valves 74 and 76 are rotated clockwise as viewed in FIG. 2. The rotor and abutment valves are operatively interrelated with the corresponding chambers within the housing and with one another so that peripherally adjacent rotor lobes cooperate with inner surface 30 of the rotor chamber and the end walls of the chamber to define a sealed moving pocket by which the hydraulic drive fluid is transferred from the inlet to the outlet port. Moreover, the radially outer surface of the lobes of the abutment valves sealingly engage the rotor in the hub areas thereof between adjacent rotor lobes to seal against fluid leakage around the hub in a direction opposite the direction of rotation of the rotor. Heretofore, sealing against fluid leakage from the high pressure side of a rotor lobe to the low pressure side thereof has been achieved in various ways including precision machining of the outer end of the rotor lobe and inner surface of the rotor chamber, or the use of a resilient or fibrous sealing element carried by the rotor lobe and engagable with the peripheral surface of the rotor chamber. Further, sealing engagement between an abutment valve lobe and the rotor hub to reduce leakage of high pressure fluid thereacross has been achieved generally by precision machining of the stator and hub surfaces. Such machining operations are extremely expensive and time consuming and thus add considerably to the cost of production. Moreover, machined sealing surfaces do not provide the degree of sealing engagement required to achieve effective sealing, whereby an undesirable amount of leakage exists even when the machining is extremely precise. Further, although theoretically frictionless even under heavy loading, in practice these surfaces can not be held in complete sealing engagement at different temperatures.

The provision of flexible or resilient sealing elements in the space between the rotor lobes and rotor chamber is undesirable in that such elements are structurally weak and have poor wear characteristics, whereby they are subject to damage and deterioration requiring frequent replacement thereof.

ROTOR LOBE SEAL In accordance with another aspect of the present invention, sealing against fluid leakage across a rotor lobe is achieved by a unique seal arrangement which is extremely effective in reducing the amount of leakage heretofore experienced. More particularly, each rotor lobe 112a, lll2b and M20 is provided with a corresponding longitudinally extending dovetailed recess 126 opening inwardly of outer surface 114, as is best illustrated in FIGS. 6 and 6A of the drawing depicting the arrangement in conjunction with rotor lobe 112C. Recess 1126 is longitudinally coextensive with the rotor lobe 112C and is defined by a pair of opposed side walls 128 and I30 which diverge relative to one another in the direction from surface 114 towards rotor axis A. The recess further includes a bottom wall defined by opposed bottom wall portions 132 and 133 extending inwardly of the recess from the corresponding side walls 128 and 130. Bottom wall portions 132 and 133 extend at an angle relative to one another and intersect along a longitudinal line extending generally centrally of the recess. Preferably, recess 126 is provided in the lobe by making the rotor of powdered metal in a die which has the desired recess contour. It will be appreciated, however, that the rotor can be otherwise produced and the recess provided therein in any suitable manner.

A sealing element 134, preferably in the form of a hardened steel pin, is disposed in recess 126 and is of a length longitudinally coextensive with the recess. Preferably, the pin is of solid cylindrical construction and is of a diameter slightly greater than the circumferential space between the outermost edges of side walls 128 and 130 of recess 126. Moreover, for the reason pointed out hereinafter, the diameter of pin 134 is such that a portion of the pin designated 134a in FIG. 6A, projects radially outwardly of outer surfaces 114 of the recess when the pin is disposed in engagement with bottom wall portions 132 and 133. Further, outer surface 114 is spaced from inner surface 30 of the rotor chamber to define clearance space 136 which has a radial dimension greater than the distance pin portion 134a extends beyond lobe surface 114. Clearance space 136 together with the dimensional relationship between pin 134 and recess 126 provides for a fluid inlet passage 138 to exist between pin 134 and recess wall 130 when the pin is displaced outwardly of the recess to engage inner surface 30 of the rotor chamber as illustrated in FIG. 6. The radial dimension of clearance space 136 may vary, as may the size of the pin and the circumferential distance between the outer edges of walls 128 and 130, so long as fluid under pressure behind the rotor lobe can enter recess 126 between the pin and recess wall 130. Fluid under pressure entering the recess in this manner displaces pin 134 both radially outwardly and circumferentially into line contact with recess wall 128 and chamber surface 30. It will be appreciated, that many recess configurations could be provided to support the pin for engagement with the chamber surface and a wall of the recess in this manner; however, to be low in friction the included angle between the dovetail sides should be at least 15.

In operation of the pin and recess sealing arrangement, when one of the rotor lobes moves past end 122a of inlet passage 122 during rotation of the rotor, hydraulic fluid under pressure from the inlet passage flows through clearance space 136 and into pin recess 126 through passage 138. The high pressure fluid also flows through the restriction defined by the space between pin portion 134a and chamber wall 30, whereby a pressure drop exists on opposite sides of the pin tending to pull the pin outwardly of recess 126. This pressure drop together with high pressure fluid entering recess 126 through passage 138 displaces pin 134 outwardly and circumferentially as described hereinabove.

The trailing end of the fluid pocket ahead of the one rotor lobe is thus immediately sealed and the leading end of the pocket communicates with outlet pasaage 124 releasing the fluid in the pocket for flow through the outlet passage. Therefore, the fluid pressure in the pocket ahead of the one rotor lobe is reduced and a pressure drop exists across the one rotor lobe. The pressure drop provides for the high pressure fluid adjacent the back side of the one rotor lobe to exert a force on pin 134 from within pin recess 126 which is operable to maintain the pin in tight sealing engagement with chamber surface 30 and recess wall 128. It will be noted that the pressure of the hydraulic fluid is exerted along the entire length of the pin and circumferentially thereof to an extent well in excess of in the embodiment illustrated, thus to partially lower the force and hence the sliding friction between the pin and the dovetailed face. It will be further noted that pin 134 is free to rotate relative to recess 126 and in response to movement of the rotor lobe relative to surface 30, thus to provide for uniform wear of the pin surface and retention of the cylindrical contour thereof both to prolong pin life and to maintain sealing efficiency.

As mentioned hereinbefore with regard to rotor chamber 24, surface portions 30a and 30b of the chamber blend with the corresponding ends of surface portion 30 and diverge with respect to chamber axis A. The free ends of surface portions 300 and 30b are spaced from axis A a distance sufficient to provide for pins 134 to be spaced therefrom whenthe pins are in their radially outermost positions in the corresponding lobe recess 126. The circumferential portions of surfaces 30a and 30b between the free ends thereof and the corresponding end of surface portion 30 provide for the spaced relationship to be maintained so that the pin of a lobe approaching inlet port 122 will not sealingly engage the chamber surface ahead of the port and thus deadhead the unit. Further, portions 300 and 30b of the rotor chamber surface provide for a pin 134 to be gradually pushed radially inwardly of its dovetailed recess 126 as the corresponding lobe approaches surface portion 30, and define a transitional area in the approach to surface portion 30 in which spinning or rotation of a stationary lobe pis is initiated. Further, as pin 134 approaches the outlet passage, the pin gradually moves radially outwardly as it moves onto surface 30b which has a larger radius than surface 30. This decompresses the high pressure fluid before it is exposed to the lower pressure outlet port. FIG. 6B shows an alternate or additional method of decompression by having the bottom of the dovetail-sealing pin groove gradually communicate with the outlet port.

As further mentioned hereinabove, recesses 118 of abutment valves 74 and 76 are of an axial length slightly greater than the axial thickness of housing member 16. It will be appreciated, therefore, that when a rotor lobe is disposed in an abutment valve recess 118, the corresponding lobe pin 134 can move axially of the recess so that one end of the pin is positioned axially beyond the plane of the inner surface of the corresponding one of the housing members 12 and 14. To assure that the pin is displaced axially back into the housing as the rotor lobe leaves the abutment valve recess, tapered lead-in recesses 119 are provided in housing members 12 and 14 on circumferentially opposite sides of abutment valve chambers 26 and 28. Each recess 119 is radially spaced from rotor chamber axis A a distance corresponding to the radial position of a lobe pin 134 relative to axis A so that the pin end will engage the tapered recess surface and be pushed axially inwardly of the housing as the rotor rotates.

FLUID PRESSURE VALVING IN ROTOR CHAMBER As is best seen in FIGS. 2 and 4 of the drawing, the axis of inlet passageway 122 opens longitudinally into the rotor chamber from housing member 12. Housing member 12 is provided with a laterally extending fluid passage 140 connectable to a source of hydraulic fluid under pressure and having an inner end in fluid communication with inlet passage 122. Further, housing member 14 is provided with a longitudinally extending recess 144 located axially opposite and in alignment with inlet passage 122, whereby the hydraulic fluid entering the rotor chamber flows axially into recess 144 to provide for a uniform distribution of fluid pressure across the trailing face of a rotor lobe moving past the inlet passage. Similarly, fluid outlet passage 124 opens longitudinally into the rotor chamber from housing member 12, and a laterally extending outlet passage 146 is provided in housing member 12 which opens laterally into passage 124. Passage 146 is connectable to a line or conduit for returning the hydraulic fluid to the sump or other source from which the fluid is supplied. Housing member 141 is provided with a recess 14% axially opposite and in alignment with outlet passage 124 to provide for a portion of the fluid released from a pocket behind a given rotor lobe to spread longitudinally and in a direction opposite to that of the outlet passage to assure maintaining a balanced force condition on the rotor during operation thereof.

In addition to the sealing function provided by the pin and recess arrangement described hereinabove for the rotor lobes, the pin and recess structure provides a valving function operable to gradually release high pressure fluid from a fluid pocket when the rotor lobe defining the forward end of the pocket reaches the outlet passage. More particularly, as illustrated in FIG. 68, when a rotor lobe such as lobe 112C, for example, approaches outlet passage 12 1 the portion of lobe recess 126 filled with hydraulic fluid under pressure moves into communication with end 12411 of the outlet passage before rear wall 113 of the lobe reaches end 124a of the passage. Accordingly, at the instant recess 126 communicates with outlet passage end 1240 fluid under pressure in the recess is released to flow into the outlet passageway establishing a pressure drop between the fluid pocket behind the rotor lobe and recess 126. This pressure drop causes fluid under pressure behind lobe 112C to flow through clearance space 136 and fluid passage 138 into recess 126 and thence into outlet passage 124. Fluid flow in this manner provides an initial flow of high pressure fluid into the outlet passageway reducing the pressure in the fluid pocket behind rotor 112e, whereby when rear face 113 of the lobe communicates with the outlet passage there has been an initial drop of pressure in the pocket to substantially lessen pulsing movement of the rotor which would result from sudden direct communication of the fluid pocket with the outlet passage. It will be appreciated that recess 148 in housing member 14 opposite outlet passageway 124 has a peripheral contour corresponding to that of outlet passage 124 so that the valving action operates to release fluid under pressure in axially opposite directions relative to the lobe recess for the purpose of maintaining balanced force conditions on the rotor.

ROTOR HUB-ABUTMENT VALVE SEAL With reference now to the sealing engagement relationship between the hub portion of the rotor and the lobes of the abutment valves, reference is made to FIGS. 2 and 8 of the drawing. The areas of hub portion of rotor 11) which extend between circumferentially adjacent ones of the rotor lobes 112a, 112b and 1120 are each provided with a corresponding hydraulic fluid actuated seal arrangement designated generally by the numeral 150. The seal arrangements in the rotor hub areas and the cooperative sealing engagement of the abutment valve lobes therewith are identical and, accordingly, only one will be described in detail, namely that associated with rotor lobes 112a and 111%. Sea] arrangement is defined by a seal plate 152 longitudinally coextensive with the rotor chamber ahd having circumferentially opposite ends 154 and 156 loosely disposed in corresponding slots provided in the radially inner or root ends of rotor lobes 112a and 112i). Preferably, plates 152 are steel plates formed to an arcuate contour to provide an arcuate outer surface 158 engagable with cylindrical outer surfaces 120 of the abutment valve lobes. in the illustration in FIG. 8, lobe surface 120 of lobe 1160 of abutment valve 76 is depicted.

Plate 152 is provided with a plurality of openings 162a-g extending therethrough for the purpose set forth more fully hereinafter. Further, the hub portion between rotor lobes 112a and 11212 is provided with a plurality of recesses 164a-f numbering one less than plate openings 162a-g and which are longituidnally coextensive with the rotor and open radially outwardly behind plate 152. For the purpose set forth more fully hereinafter, the longitudinally extending side walls of each recess 164a-f preferably are inclined to converge in the direction from the outer open ends thereof towards the bottom thereof. However, the recesses could be otherwise contoured in cross section. Adjacent ones of the recesses 164a-f are spaced apart by a tooth-like radial projection 168 having an outer face 170 radially spaced from the inner surface of plate 152. Such spacing provides for circumferential communicaton between adjacent recesses. Each recess is provided with a radially displaceable fluid pressure applicator 166, preferably in the form of a cylindrical hardened steel pin which is longitudinally coextensive with the corresponding recess. Each pin is adapted to engage and exert a force against a corresponding overlying portion of plate 152 to displace the plate radially outwardly of the rotor axis and against cylindrical outer surface 120 of the abutment valve as set forth hereinafter.

Openings 162ag in plate 152 define fluid passages for communicating recesses 16411-1 with fluid in the area between plate 152 and abutment valve 76 and are equidistant between the seal pins 166. End openings 162a and 162g are in the form of slots so as to permit movement of plate ends 154 and 156 inwardly of their corresponding support slots without closing the passages. The remaining openings preferably are circular apertures. The several openings are illustrated in FIG. 4 as being disposed in a row extending substantially centrally of the longitudinally opposite ends of the plate. It will be apparent from the description hereinafter, however, that the contours of the openings as well as the disposition thereof can be varied without departing from or affecting the purpose and operation thereof. Openings 162b-f are each disposed in overlying realtionship with a projection 168 between adjacent recesses in the hub. Further, openings 162b-f each have a dimension in the circumferential direction which provides for the opening to be closed by covering engagement of abutment valve surface 120 therewith, for the purpose set forth below.

During operation of the hydraulic motor depicted in FlGS. 2 and 8, rotor 40 is driven in a counterclockwise direction, whereby abutment valves components 74 and 76 are rotated clockwise by the meshing engagement of rotor gear 68 with the corresponding abutment valve gear 100. The abutment valve diameters, as mentioned hereinbefore, are each two-thirds the hub diameter of the rotor, and the gear ratio between rotor gear 68 and an abutment valve gears 100 provides for the abutment valves to be rotated one-half faster in rpm than the rotor. Further, the rotor and abutment valves are interrelated for the relative rotation therebetween to provide for a lobe of one or the other of the abutment valves to always be in sealing engagement with the rotor hub, and for a recess of the other abutment valve to be positioned to receive a lobe of the rotor. As illustrated in FIGS. 2 and 8 of the drawing, the rotor and abutment valve components are in an operative position thereof in which a lobe of abutment valve 76 sealingly engages the rotor hub and a recess of abutment valve 74 receives lobe 1l2b of rotor 40. The cylindrical lobe surfaces of the abutment valves have a circumferential dimension corresponding substantially to the circumferential dimension of sealing plate 152 between adjacent lobes of rotor 40.

With reference now to FIG. 8 in particular, the rotor hub and abutment valve lobe sealing relationship will be described in detail. Sealing engagement between the abutment valve lobe and plate 152 is always along a line between rotor axis A and the corresponding abutment valve axis which in this instance is axis C of abutment valve 76. The line of sealing engagement is designated X in FIG. 8. When the rotor and abutment valve are relatively positioned for initial sealing engagement between abutment valve surface 120 and plate 152, end 120a of surface 120 engages plate end surface 1580 at line X, whereby plate opening 1620 at end 154 of the plate is opened to high pressure fluid entering inlet passage 122. Accordingly, hydraulic fluid under pressure enters hub recess 164a adjacent end 154 of plate 152 and biases the corresponding pin 166 radially outwardly against the inner surface of plate 152 and a wall of the recess, as illustrated in FIG. 8. The hydraulic force on pin 166 biases plate 152 against surface 120 of abutment valve lobe 11611 to effectively seal against leakage of high pressure fluid between the plate and valve in a direction opposite to the direction of rotation of rotor 40. The position of pin 166 in recess 164a blocks the flow of high pressure fluid to the next adjacent recess l64b until such time as relative rotation between the rotor and abutment valve so positions plate 152 and abutment valve surface 120 that plate opening 162b is uncovered and thus opened to the high pressure fluid entering inlet passage 122. Hydraulic fluid under pressure then enters passage 1162b and hub recess 16% vto bias the corresponding pin 166 radially outwardly against plate 152 and a wall of recess 164b to bias plate 152 radially outwardly into sealing engagement with abutment valve surface-120. At the same time, fluid under pressure flows through passage 162b into recess 164a, whereby the fluid pressure against pin 166 in recess 164a is equalized and the latter pin no longer is forced against plate 152. Rotor and abutment valve rotation then brings these components to the position illustrated in FIG. 8, wherein opening 1620 is exposed to high pressure fluid for the fluid to enter hub recess 164C to bias the corresponding pin 166 radially outwardly as described hereinabove and for the pressure against pin 166 in recess 16% to be equalized. It will be noted that the next adjacent plate opening 162d is closed by surface of the abutment valve, whereby fluid under pressure can not flow therethrough into hub recess 164d at this time. This relationship exists between each of the plate openings beginning with opening 162b when sealing engagement between the rotor hub and abutment valve is initiated. End opening 162a, however, is not so closed, whereby sealing engagement between plate end 158a and end 120a of abutment valve surface 120 is established immediately upon movement of these surfaces into engagement at the beginning of the sealing operation. Continued rotation of the rotor and abutment components from the positions illustrated in FIG. 8 causes plate opening 162d to be uncovered for flow of hydraulic fluid under pressure into recess 164d for the corresponding pin 166 to be radially biased outwardly against plate 152 to maintain sealing engagement between the plate and abutment valves surface. Again, fluid flow into recess 164c relieves the bias on the corresponding pin. This sequential uncovering of the plate openings and the resulting biasing and release of the pins in the adjacent hub recesses continues until end 1201) of surface 120 engages with end 158b of plate 152.

At the moment when end 12% of surface 120 and end 1581) of plate 152 move out of sealing engagement, the rotor and abutment valves are relatively positioned for the trailing lobe l12b of the rotor in FIG. 8 to enter the recess in abutment valve 76 behind end surface 12Gb thereof, and for lobe end surface 120a of a abutment valve 74 to engage the end surface of the sealing plate 152 between rotor lobes ll2b and 1120. Sealing engagement relationship between a lobe of abutment valve 74 and sealing plate 152 between rotor lobes 112b and 112C is thus established and is maintained in the manner described above with regard to the sealing between lobe 116a of abutment valve 76 and plate 152 between rotor lobes 112a and 112b. The point of sealing engagement between the rotor hub and abutment valve 74 is along a line designated Y in FIG. 2 and extending between rotor axis A and abutment valve axis B When sealing engagement between the lobe of abutment valve 74 and plate 152 between rotor lobes 11212 and 112C terminates as a result of the rotation of the rotor and abutment valves, plate 152 between rotor lobes 1l2b and 112C moves into sealing relationship with lobe l16b of abutment valve 76. Accordingly, it will be appreciated that the rotor and abutment valve components are continuously sealed against leakage of high pressure fluid therebetween in a direction opposite the direction of rotation of the rotor during operation of the hydraulic motor. The particular hydraulically actuated seal arrangement provides for better sealing engagement between the rotor and abutment valve components than heretofore possible, whereby fluid leakage of the character sealed against is appreciably reduced to increase motor efficiency. Further,

the rotation of the abutment valve components onehalf faster in rpm than the rotor, together with the relative diameters of the outer surface of the abutment valve and the outer surface of the rotor hub as defined by sealing plates 152, provides for rolling contact between the sealing plates and cylindrical abutment valve surfaces to take place in a manner whereby plates 152 tend to drive the abutment valve. This driving action eliminates back lash between the rotor and abutment valve gears.

While the configuration of the hub recesses 16411-f in cross section can vary, preferably the side walls of the recesses are inclined at an included angle of 45 relative to a radial axis through the bottom of the recess. This provides for the biasing force of the hydraulic fluid to be applied to pins tee in a manner whereby the pressure engagement of the pins against the side wall of the recess and the inner surface of plate 152 is substantially equal. Such equal pressure engagement best assures against leakage of fluid between the pin and recess wall and between the pin and plate 152. Further, the 45 included angle provides for a radially outward force to be applied by the pins against plate 152 while achieving the desired sealing engagement between the pins, recess wall and seal plate. In this respect, if the incline of the recess wall is too great, the radial force of the pin against plate 152 is increased, thus increasing the sealing pressure between the plate and abutment valve lobe. On the other hand, if the incline of the recess wall is eliminated then there will be places where the plate 152 is inadequately biased into sealing engagement with the abutment valve lobe. While the 45 included angle provides the best sealing relationship and radial pin force combination, other angles can be employed without departing from the principles of the seal arrangement. It should be noted too that it is only necessary to incline the wall of the recess which is the trailing wall with respect to the direction of rotation of the rotor. lnclining both walls advantageously provides for the motor to be operated in either direction of rotation which, of course, is most desirable. Further, the radial depth of the recesses and the diameter of the pins as well as the number of recesses employed can be varied, it only being necessary to provide sufficient clearance between the pins and the bottom of the recess to permit the hydraulic fluid to flow therebetween.

ABUTMENT VALVE SHAFT SEAL In accordance with yet another aspect of the present invention, internal fluid leakage axially along outer portions of the abutment valve support shafts is effectively reduced to further increase motor efficiency. In this respect, as mentioned hereinabove, the opposite ends of each of the abutment valve shafts is provided with a bearing and seal arrangement designated generally by numeral 88 disposed about the corresponding abutment valve shaft portion and between the shaft and a cooperative recess or opening in the housing for the shaft portion. The abutment valve shaft bearing and sealing arrangements are identical, and accordingly, only one of the arrangements will be described in detail. In this respect, the seal arrangement between shaft portion 90 of abutment valve 74 and wall portion 98 of housing member 12, illustrated in FIGS. 3 and 5, will be described. Shaft portion 90 includes a first portion 180 extending axially from cylindrical disc portion 182 adjacent the corresponding end of the abutment valve body. Shaft portion further includes a terminal portion 184 of smaller .diameter than portion and extending through an opening in wall 98 and into the gear chamber as described hereinabove. Wall 98 of housing includes an entrance portion I86 opening from the abutment valve chamber side thereof and a second portion 188 of smaller diameter extending axially from entrance portion 186 and opening into the gear chamber. The abutment valve side of housing wall 98 is a high pressure area into which operating fluid under pressure leaks from the abutment valve chamber, and the gear chamber is a low pressure area, whereby a pressure drop exists across wall portion 98. The area along shaft portion 184 between the high and low pressure sides of wall 98 defines a relatively short fluid leakage path. Considerable fluid leakage can result in this area due to the shortness of the leakage path and the pressure differential across the housing wall. Heretofore, efforts to reduce the fluid leakage between components of devices of the character of the present invention has involved the precision machining of bearing components and shafts, the use of elaborate seal arrangements, or structural arrangements intended to lengthen the leakage path in an effort to reduce the amount of leakage. The previous designs are reasonably expensive, often result in creating undesirable bearing loads and reducing bearing life and, moreover, are not as effective as desired with regard to lessening the degree of leakage.

In accordance with the present invention, a bearing and seal arrangement is provided which is of a floating character, whereby the degree of precision required in machining the various components is reduced, bearing life is increased and deliterious bearing loads are minirnized. Further, while the leakage path is quite short the bearing and seal assembly is responsive to fluid pressure on the high pressure side of the housing wall to increase sealing engagement between components of the seal assembly in a manner whereby leakage across the housing wall is substantially eliminated. More particularly, in this respect, the bearing and seal arrangement of the present invention includes a stepped bearing component 190 of sintered bearing bronze, or the like, in the form of a sleeve having a cylindrical inner surface 192 surrounding and sealing engaging the outer surface of shaft portion 184 and a radial face 193 engaging end face 180a of abutment valve shaft portion 180. The radially outer surface of bearing 1% is stepped to define a flange portion 194 having a load face 194a engaging the high pressure face 98a of housing wall 98. The stepped bearing 1% further includes a sleeve portion 196 in the circumferential space between shaft portion 184 and portion 188 of the opening through wall 98, and a shoulder portion 198 intermediate flange portion 194 and sleeve portion 196. Sleeve portion 196 is of smaller diameter than portion 188 of the opening through wall 98 to provide a radial clearance space 189 therebetween. Shoulder portion 198 extends axially into the entrance end 186 of the opening in wall 98 and terminates therein in axially spaced relationship with respect to wall 200 defining the inner end of entrance portion 186. Further, shoulder portion 198 has a diameter slightly less than the diameter of the entrance portion of the recess 186, thus to define a circumferential space 202 between the shoulder portion and recess 186.

A resilient O-ring seal 204 and a back-up ring 206 are disposed in the circumferential chamber defined by wall 200 and the opposed wall portion 198a of shoulder 198 of the bearing to seal against fluid leakage between the bearing and the opening through wall 98, as set forth more fully hereinafter. When the abutment valve chamber is pressurized back up ring 206 will be pushed against wall 200. Further, radial face 193 of bearing element 190 disposed against ene face 180a of shaft portion 180 of the abutment valve is provided with a diametric extending recess 208 defining a pair of fluid passageways in communication at their radial outer ends with high pressure fluid flowing axially along abutment valve bearing 94 and communicating at their radial inner ends with the outer surface of shaft portion 194.

Bearing 190 is a floating bearing in that clearance spaces 189 and 202 permit radial or transverse movement of the bearing relative to wall 98 in response to corresponding movement of the abutment valve shaft. This arrangement advantageously provides for sealing without the bearing sleeve 190 taking heavy loads. Each clearance 189 and 202 is greater than the clearance between the abutment valve shaft and its main support bearing 94. The bearing load on the sleeve 190 is thus determined by friction between faces 194a and 98a. Recess 208 in bearing 190 permits hydraulic fluid under pressure to exert an axial force against sleeve 190 to maintain flange 194 against wall face 98a at all imes during motor operation. Sealing element 204 is, of course, disposed between sleeve 190 and the opening through wall 98 under a degree of radial compression which prevents any fluid leakage therepast. It will be appreciated, therefore, that by providing for the shaft portion to be supported and sealed by a floating bearing and seal arrangement, less accuracy in machining in the sealing areas between the components of the assembly is required, thus decreasing manufacturing expenses, and at the same time a more effective seal is achieved than heretofore possible whereby fluid leakage is substantially eliminated to further increase the efficiency of motor operation.

in order to maintain a balance in the fluid pressure acting against the bearing and seal arrangements at opposite ends of the abutment valves, the abutment valves are provided with longitudinally extending fluid passageways 212 extending through the lobed portions thereof. Passageways 212 provide for the opposite ends of the abutment valve shafts to be maintained in fluid communication.

it will be appreciated, of course, that a certain amount of fluid leakage will occur along the shaft portions at the opposite ends of the abutment valve components. The fluid leakage occurring along the shaft portion at the end opposite the end associated with the housing wall 98 can be delivered to bearing assembly 48 at the corresponding end of the motor by a passageway 214 opening into the bearing recess from shaft recess 86 adjacent shaft portion 84, as illustrated in FIG. 3. Leakage along the shaft portion extending through housing wall 98 can be drained or returned to the sump area by means of an appropriate passage 216 in the motor housing.

From the foregoing description of a preferred embodiment of the present invention, it will be appreciated that in accordance with the present invention a positive displacement device for hydraulic fluid is provided comprising a unique rotor and abutment valve combination wherein the rotor has three lobes and the abutment valves each have two lobes operatively interrelated therewith whereby the device is operable to provide a low speed high torque hydraulic motor which is physically compact, inexpensive to manufacture and maintain and has improved operating characteristics. It will be appreciated further that in accordance with the present invention a positive displacement device for fluids is provided having improved internal fluid sealing characteristics by which efficiency in operation of the device is achieved and which includes a new and improved rotor lobe and chamber seal arrangement, a new and improved rotor abutment valve seal arrangement and a new and improved abutment valve shaft bearing and seal arrangement. While the rotor of the hydraulic motor is described herein as being driven in only one direction, it will be appreciated that the motor is operable in either direction merely by reversing the fluid inlet and outlet ports. Further, it will be appreciated that the cross sectional contours of the abutment valve recesses and rotor lobes can be varied from the specific configurations illustrated without departing from the principles of the present invention.

Still further, it will be appreciated that the number of recesses and pins provided in the rotor hub between adjacent lobes thereof for biasing the sealing plate against the abutment valve lobes can be varied and is not limited to the specific number illustrated and described in conjunction with the preferred embodiment. Moreover, while it is preferred that the fluid passages for the recesses be defined by openings through the sealing plate, it will be appreciated that fluid could otherwise be delivered to the recesses, such as by valved passageways leading to the recesses, for example. Many modifications of the various structural relationships described herein will be suggested to those skilled in the art upon reading the foregoing description, and such modifications can readily be employed without departing from the principles of the present invention.

Further, as mentioned hereinbefore, while the three lobe-two lobe concept with the abutment valve axes spaced 60 is preferred for a hydraulic motor, a four lobe-two lobe arrangement with abutment valve axes spaced 45 is preferred for a hydraulic pump. The latter arrangement is schematically illustrated in FIG. 9 wherein it will be seen that the rotor 300 is provided with four rotor lobes 302 spaced apart equidistant circumferentially of the rotor axis, whereby adjacent lobes are spaced apart in accordance with the present invention, the two two lobed abutment valves 304 have their axes circumferentially spaced apart onehalf the angular distance between adjacent rotor lobes, and, accordingly, the abutment valve axes are spaced apart 45. In addition to the advantages described hereinabove with regard to a three lobe-two lobe arrangement, the four lobe-two lobe arrangement advantageously enables further increasing the inlet and outlet port areas to increase the fluid displacement capability for a pump.

As many possible embodiments of the present invention may be made and as many possible changes may be made in the embodiment herein described, it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the present invention and not as a limitation.

Having thus described my invention, l claim:

1. A positive displacement device for fluids comprising housing means having rotor and abutment valve chambers, said rotor chamber including an arcuate wall and said abutment valve chamber including a circular wall intersecting said rotor chamber wall, cooperable rotatable rotor and abutment valve members disposed respectively in said rotor and abutment valve chambers, fluid inlet and outlet ports at spaced locations about said rotor chamber wall and opening axially into said rotor chamber, said rotor comprising a hub and at least one lobe projecting radially outwardly from said hub, said lobe having an outer end provided with a longitudinally extending recess opening radially outwardly of said end, a sealing pin in said recess, said recess opening having a circumferential width less than the diameter of said pin, said outer end of said lobe and said rotor chamber wall being radially spaced such that said recess communicates with said rotor chamber when said pin engages said rotor chamber wall for fluid under pressure to enter said recess from said rotor chamber, said outlet port having an end disposed in the path of movement of said recess for communicating said outlet port with said recess to reduce the fluid pressure behind said rotor lobe prior to movement of said rotor lobe past said end of said outlet port.

2. A positive displacement device for fluids comprising a housing having a rotor chamber and a pair of abutment valve chambers therein, said rotor chamber having an arcuate wall and said abutment valve chambers each having a circular wall intersecting the rotor chamber wall, a rotor in said rotor chamber having a hub portion and three rotor lobes spaced equidistant thereabout and extending radially therefrom, an abutment valve in each of said abutment valve chambers each including diametrically opposed pairs of lobes and recesses, said abutment valve lobes having outer ends sealingly engagable with the rotor hub between adjacent rotor lobes, fluid inlet and outlet passages opening into said rotor chamber at spaced locations about said rotor chamber wall, means interconnecting said rotor and abutment valves for simultaneous rotation in their respective chambers, and fluid pressure responsive seal means between said abutment valve lobes and said rotor hub, said seal means including sealing elements between adjacent rotor lobes and carried by said rotor for movement therewith and radial displacement relative thereto, means between said rotor hub and sealing elements for displacing said sealing elements outwardly of said rotor hub, said sealing elements carried by said rotor including radially displaceable sealing plates extending between adjacent rotor lobes, and said means for displacing said sealing elements including at least one plate biasing member between each plate and the rotor hub, said biasing member being movable radially outwardly with respect to said rotor hub to displace said sealing plate radially outwardly.

3. A positive displacement device for fluids comprising housing means having respective chambers therein for cooperably lobed rotor and abutment valve members, bearing means supporting said rotor and abutment valve members for rotation in their respective chambers, said abutment valve members including corresponding shaft portions extending into shaft openings therefor in wall means of said housing means, and seal means between at least one of said abutment valve shaft portions and the corresponding opening therefor, said seal means including a floating bearing sleeve between said one abutment valve shaft portion and opening, said sleeve having an outer surface within and radially spaced from the inner surface of said opening and an inner surface in engagement with said one shaft portion to provide controlled leakage along said one shaft portion, and an annular seal element radially compressed in the space between said sleeve and opening, said housing wall means having a surface facing said chambers and said bearing sleeve being rotatably, radially and axially displaceable relative to said wall means, said sleeve including a radial load face engaging said wall surface and an axially opposed fluid pressure surface facing the corresponding abutment valve chamber and exposed to fluid under pressure therein for maintaining said load face in engagement with said wall surface, said sleeve further including a second radial face disposed axially inwardly of said opening, means in said opening defining an abutment axially spaced from said second radial face, said annular seal element being disposed in the space between said second radial face and said abutment.

4. A positive displacement device for fluids comprising housing means having high fluid pressure and low fluid pressure zones therein, chamber means in said high pressure zone and including rotor and abutment valve chambers for cooperatively lobed rotatable rotor and abutment valve members, bearing means supporting said abutment valve member for rotation, said housing means including a wall between said high and low pressure zones, shaft means for said abutment valve member, said wall including an opening through which at least a portion of said shaft means extends and defining a leakage path for fluid from said high pressure zone to said low pressure zone, and floating bearing and seal means between said wall and said portion of said shaft means for sealing said leakage path, said bearing and seal means including a sleeve bearing on said portion of said shaft means and between said portion of said shaft means and said opening, said sleeve bearing having an inner surface engaging said shaft portion to provide controlled leakage along said shaft portion between said high and low pressure zones, said sleeve having an outer surface within said opening and radially spaced from the inner surface of said opening, a resilient seal element radially compressed between said outer surface of said sleeve bearing and said inner surface of said opening, one end of said sleeve bearing including a radial load face engaging the surface of said wall about said opening on the high pressure side of said wall, said one end of said sleeve further including a fluid pressure surface axially opposed with respect to said load surface and exposed to fluid under pressure in said high pressure zone for said high pressure fluid to press said load surface against said wall surface.

5. The positive displacement device of claim 4, said sleeve bearing further including a radial shoulder within said opening, an opposed shoulder in said opening spaced from said radial shoulder, and said resilient seal element being disposed between said shoulders.

6. A hydraulic, rotary abutment motor or pump comprising a housing having a rotor chamber and a pair of abutment valve chambers therein, said rotor chamber having an arcuate wall and said abutment valve chambers each having a circular wall intersecting the rotor chamberv wall, a rotor in said rotor chamber having a hub portion and three rotor lobes spaced substantially equidistant thereabout and extending radially therefrom, an abutment valve in each of said abutment valve chambers each including substantially diametrically opposed pairs of lobes and recesses, said abutment valve lobes having outer ends sealingly engageable with the rotor hub between adjacent rotor lobes, the circumferential angle between the axes of said abutment valves being substantially 60, fluid inlet and outlet passages opening into said rotor chamber at spaced locations about said rotor chamber wall, and means interconnecting said rotor and abutment valves for simultaneous rotation in their respective chambers, fluid pressure responsive seal means between said rotor lobes and rotor chamber wall, said seal means including a sealing element carried by each of said rotor lobes for movement therewith and radially outward displacement relative thereto, said sealing element being a cylindrical pin extending longitudinally of said rotor lobe, said rotor lobe including a longitudinal recess open toward said rotor chamber wall, and said pin being disposed in said recess for radially outward displacement relative thereto and into engagement with said rotor chamber wall, said opening into said lobe recess being circumferentially narrower than the diameter of said pin, said rotor chamber wall including a circular portion between said inlet and outlet passages having a radius of curvature relative to the rotor chamber axis less than the maximum radial dimension along said rotor lobe to the outermost point of said pin in said lobe recess, and said rotor chamber wall including a lead-in portion at each end of said circular portion and having one end merging with the corresponding end of said circular portion and another end radially spaced from said axis a distance greater than said maximum radial dimension.

7. A positive displacement device for fluids comprising, housing means having rotor and abutment valve chambers, said rotor chamber having an arcuate wall and said abutment valve chamber having a circular wall intersecting with said rotor chamber wall, rotatable rotor and abutment valve members disposed respectively in said rotor and abutment valve chambers, fluid inlet and outlet openings at spaced locations about said rotor chamber wall, said rotor and abutment valve including cooperable means therebetween for sealing against fluid flow from said inlet to said outlet between said rotor and abutment valve, said cooperable means including fluid pressure actuated sealing means on said rotor and a lobe surface on said abutment valve sealingly engagable withsaid sealing means, said sealing means including plate means carried by said rotor, fluid actuated means for displacing said plate means radially outwardly of said rotor toward said lobe surface, and means for directing fluid flow to said fluid actuated means, said rotor including a hub and said plate means overlying said hub, said fluid actuated means including pressure applying elements between said hub and plate means and displacable radially outwardly of said hub to displace said plate means into sealing engagement with said lobe surface.

8. The positive displacement device of claim 7, wherein said plate means and lobe surface are relatively movable in progressive engagement and said fluid actuated means is operable to sequentially displace said pressure applying elements for said plate means to sealingly engage said lobe surface progressively during said movement.

The positive displacement device of claim 8, wherein said pressure applyirig' elements are pins extending longitudinally of said rotor in corresponding longitudinally extending recesses opening toward said plate means, and said plate means includes passageway means for fluid under pressure to enter said recesses sequentially to displace said pins into engagement with said plate means.

10. The positive displacement device of claim 9, wherein said longitudinally extending recesses each include a side wall having a plane intersecting the plane of said plate means at an interior angle less than said pins being cylindrical and having line contact with said side wall of the corresponding recess and with said plate means when in pressure engagement with said plate means.

11. A hydraulic motor comprising housing means having an arcuate rotor chamber and fluid inlet and outlet passages spaced circumferentially about said chamber, a rotor disposed in said chamber for rotation in a given direction relative to the chamber axis and being rotatable in said given direction by fluid under pressure entering said chamber through said inlet passage, output means operatively associated with said rotor and driven in response to rotation of said rotor, said housing including circular abutment valve chambers parallel with and opening into said rotor chamber, an abutment valve rotatably mounted in each of said abutment valve chambers, said rotor having three radially projecting displacement lobes and said abutment valves each having two radially directed sealing lobes engagable with said rotor between adjacent displacement lobes thereof during rotation of said rotor in said given direciton to seal against fluid flow from said inlet passage toward said outlet passage in a direction opposite said given direction, and radially outwardly displacable sealing means carried by said rotor between said displacement lobes for sealing engagement with said abutment valve sealing lobes, said radially outwardly displacable sealing means including plate means extending circumferentially between adjacent displacement lobes and fluid actuated pressure applying elements radially inwardly of said plate means for displacing said plate means toward said abutment valve sealing lobes.

12. The hydraulic motor of claim 11, wherein said rotor includes a hub portion between said adjacent displacement lobes and said pressure applying means includes cylindrical pins disposed in corresponding longitudinally extending recesses in said hub portion, said plate means including fluid passageways opening between said recesses and the outer surface of said plate means.

13. The hydraulic motor of claim 12, wherein said recesses in said hub portion include a plurality of parallel spaced apart recesses having at least one wall thereof inclined relative to said plate means, said fluid passageways in said plate means including at least one opening communicating with each recess for flow of fluid under pressure thereinto.

14. The hydraulic motor of claim 12, wherein said sealing lobes have an outer surface movable in progressive engagement circumferentially across said plate means during rotation of said rotor in said given direction, said openings to said recesses being arranged in circumferentially spaced relation along said plate means and being sequentially uncovered by movement of said lobe outer surface across said plate-means for said fluid under pressure to enter said recesses sequentially during said movement 15. A positive displacement device for fluids comprising housing means having rotor and abutment valve chambers, said rotor chamber including an arcuate wall and said abutment valve chamber including a circular wall intersecting said rotor chamber wall, cooperable rotatable rotor and abutment valve chambers, fluid inlet and oulet ports at spaced locations about said rotor chamber wall, said rotor comprising a hub and at least two lobes projecting radially outwardly from said hub, and fluid pressure actuated sealing means carried by said lobes and displaceable radially outwardly relative thereto for sealing engagemnet with said rotor chamber wall, said rotor chamber wall including a circular portion between said inlet and outlet ports and having a given radius with respect to the axis of said rotor chamber, said chamber wall further including a second portion adjacent said outlet port and merging with the corresponding end of said circular portion and divering with respect to said chamber axis, said sealing means in moving from said inlet port toward said outlet port engaging said second portion of said rotor chamber wall ahead of said outlet port to reduce the fluid pressure behind the corresponding one of said rotor lobes.

16. The positive displacement of claim 15, wherein said lobe has an outer end provided with a longitudinal extending recess opening radially outwardly of said end, and said sealing means includes a sealing element disposed in said recess and displacable outwardly of said recess opening for sealing engagement with said rotor chamber wall in response to fluid under pressure acting thereagainst in said recess.

17. The positive displacement device of claim 16,

wherein said sealing element is a metal pin and said re cess opening has a circumferential width less than the diameter of said pin, said outer end of said lobe and said rotor chamber wall being radially spaced such that said recess communicates with said rotor chamber when said pin engages said rotor chamber wall for fluid under pressure to enter said recess from said rotor chamber.

18. The positive displacement device of claim 17, wherein said recess includes opposed longitudinally extending side walls diverging inwardly from said recess

Claims (18)

1. A positive displacement device for fluids comprising housing means having rotor and abutment valve chambers, said rotor chamber including an arcuate wall and said abutment valve chamber including a circular wall intersecting said rotor chamber wall, cooperable rotatable rotor and abutment valve members disposed respectively iN said rotor and abutment valve chambers, fluid inlet and outlet ports at spaced locations about said rotor chamber wall and opening axially into said rotor chamber, said rotor comprising a hub and at least one lobe projecting radially outwardly from said hub, said lobe having an outer end provided with a longitudinally extending recess opening radially outwardly of said end, a sealing pin in said recess, said recess opening having a circumferential width less than the diameter of said pin, said outer end of said lobe and said rotor chamber wall being radially spaced such that said recess communicates with said rotor chamber when said pin engages said rotor chamber wall for fluid under pressure to enter said recess from said rotor chamber, said outlet port having an end disposed in the path of movement of said recess for communicating said outlet port with said recess to reduce the fluid pressure behind said rotor lobe prior to movement of said rotor lobe past said end of said outlet port.

2. A positive displacement device for fluids comprising a housing having a rotor chamber and a pair of abutment valve chambers therein, said rotor chamber having an arcuate wall and said abutment valve chambers each having a circular wall intersecting the rotor chamber wall, a rotor in said rotor chamber having a hub portion and three rotor lobes spaced equidistant thereabout and extending radially therefrom, an abutment valve in each of said abutment valve chambers each including diametrically opposed pairs of lobes and recesses, said abutment valve lobes having outer ends sealingly engagable with the rotor hub between adjacent rotor lobes, fluid inlet and outlet passages opening into said rotor chamber at spaced locations about said rotor chamber wall, means interconnecting said rotor and abutment valves for simultaneous rotation in their respective chambers, and fluid pressure responsive seal means between said abutment valve lobes and said rotor hub, said seal means including sealing elements between adjacent rotor lobes and carried by said rotor for movement therewith and radial displacement relative thereto, means between said rotor hub and sealing elements for displacing said sealing elements outwardly of said rotor hub, said sealing elements carried by said rotor including radially displaceable sealing plates extending between adjacent rotor lobes, and said means for displacing said sealing elements including at least one plate biasing member between each plate and the rotor hub, said biasing member being movable radially outwardly with respect to said rotor hub to displace said sealing plate radially outwardly.

3. A positive displacement device for fluids comprising housing means having respective chambers therein for cooperably lobed rotor and abutment valve members, bearing means supporting said rotor and abutment valve members for rotation in their respective chambers, said abutment valve members including corresponding shaft portions extending into shaft openings therefor in wall means of said housing means, and seal means between at least one of said abutment valve shaft portions and the corresponding opening therefor, said seal means including a floating bearing sleeve between said one abutment valve shaft portion and opening, said sleeve having an outer surface within and radially spaced from the inner surface of said opening and an inner surface in engagement with said one shaft portion to provide controlled leakage along said one shaft portion, and an annular seal element radially compressed in the space between said sleeve and opening, said housing wall means having a surface facing said chambers and said bearing sleeve being rotatably, radially and axially displaceable relative to said wall means, said sleeve including a radial load face engaging said wall surface and an axially opposed fluid pressure surface facing the corresponding abutment valve chamber and exposed to fluid under pressure therein for maintaining said load face in engagement with said wall surface, saiD sleeve further including a second radial face disposed axially inwardly of said opening, means in said opening defining an abutment axially spaced from said second radial face, said annular seal element being disposed in the space between said second radial face and said abutment.

4. A positive displacement device for fluids comprising housing means having high fluid pressure and low fluid pressure zones therein, chamber means in said high pressure zone and including rotor and abutment valve chambers for cooperatively lobed rotatable rotor and abutment valve members, bearing means supporting said abutment valve member for rotation, said housing means including a wall between said high and low pressure zones, shaft means for said abutment valve member, said wall including an opening through which at least a portion of said shaft means extends and defining a leakage path for fluid from said high pressure zone to said low pressure zone, and floating bearing and seal means between said wall and said portion of said shaft means for sealing said leakage path, said bearing and seal means including a sleeve bearing on said portion of said shaft means and between said portion of said shaft means and said opening, said sleeve bearing having an inner surface engaging said shaft portion to provide controlled leakage along said shaft portion between said high and low pressure zones, said sleeve having an outer surface within said opening and radially spaced from the inner surface of said opening, a resilient seal element radially compressed between said outer surface of said sleeve bearing and said inner surface of said opening, one end of said sleeve bearing including a radial load face engaging the surface of said wall about said opening on the high pressure side of said wall, said one end of said sleeve further including a fluid pressure surface axially opposed with respect to said load surface and exposed to fluid under pressure in said high pressure zone for said high pressure fluid to press said load surface against said wall surface.

5. The positive displacement device of claim 4, said sleeve bearing further including a radial shoulder within said opening, an opposed shoulder in said opening spaced from said radial shoulder, and said resilient seal element being disposed between said shoulders.

6. A hydraulic, rotary abutment motor or pump comprising a housing having a rotor chamber and a pair of abutment valve chambers therein, said rotor chamber having an arcuate wall and said abutment valve chambers each having a circular wall intersecting the rotor chamber wall, a rotor in said rotor chamber having a hub portion and three rotor lobes spaced substantially equidistant thereabout and extending radially therefrom, an abutment valve in each of said abutment valve chambers each including substantially diametrically opposed pairs of lobes and recesses, said abutment valve lobes having outer ends sealingly engageable with the rotor hub between adjacent rotor lobes, the circumferential angle between the axes of said abutment valves being substantially 60*, fluid inlet and outlet passages opening into said rotor chamber at spaced locations about said rotor chamber wall, and means interconnecting said rotor and abutment valves for simultaneous rotation in their respective chambers, fluid pressure responsive seal means between said rotor lobes and rotor chamber wall, said seal means including a sealing element carried by each of said rotor lobes for movement therewith and radially outward displacement relative thereto, said sealing element being a cylindrical pin extending longitudinally of said rotor lobe, said rotor lobe including a longitudinal recess open toward said rotor chamber wall, and said pin being disposed in said recess for radially outward displacement relative thereto and into engagement with said rotor chamber wall, said opening into said lobe recess being circumferentially narrower than the diameter of said pin, said rotor chamber wall including a circUlar portion between said inlet and outlet passages having a radius of curvature relative to the rotor chamber axis less than the maximum radial dimension along said rotor lobe to the outermost point of said pin in said lobe recess, and said rotor chamber wall including a lead-in portion at each end of said circular portion and having one end merging with the corresponding end of said circular portion and another end radially spaced from said axis a distance greater than said maximum radial dimension.

7. A positive displacement device for fluids comprising, housing means having rotor and abutment valve chambers, said rotor chamber having an arcuate wall and said abutment valve chamber having a circular wall intersecting with said rotor chamber wall, rotatable rotor and abutment valve members disposed respectively in said rotor and abutment valve chambers, fluid inlet and outlet openings at spaced locations about said rotor chamber wall, said rotor and abutment valve including cooperable means therebetween for sealing against fluid flow from said inlet to said outlet between said rotor and abutment valve, said cooperable means including fluid pressure actuated sealing means on said rotor and a lobe surface on said abutment valve sealingly engagable with said sealing means, said sealing means including plate means carried by said rotor, fluid actuated means for displacing said plate means radially outwardly of said rotor toward said lobe surface, and means for directing fluid flow to said fluid actuated means, said rotor including a hub and said plate means overlying said hub, said fluid actuated means including pressure applying elements between said hub and plate means and displacable radially outwardly of said hub to displace said plate means into sealing engagement with said lobe surface.

8. The positive displacement device of claim 7, wherein said plate means and lobe surface are relatively movable in progressive engagement and said fluid actuated means is operable to sequentially displace said pressure applying elements for said plate means to sealingly engage said lobe surface progressively during said movement.

9. The positive displacement device of claim 7, wherein said pressure applying elements are pins extending longitudinally of said rotor in corresponding longitudinally extending recesses opening toward said plate means, and said plate means includes passageway means for fluid under pressure to enter said recesses sequentially to displace said pins into engagement with said plate means.

10. The positive displacement device of claim 9, wherein said longitudinally extending recesses each include a side wall having a plane intersecting the plane of said plate means at an interior angle less than 90*, said pins being cylindrical and having line contact with said side wall of the corresponding recess and with said plate means when in pressure engagement with said plate means.

11. A hydraulic motor comprising housing means having an arcuate rotor chamber and fluid inlet and outlet passages spaced circumferentially about said chamber, a rotor disposed in said chamber for rotation in a given direction relative to the chamber axis and being rotatable in said given direction by fluid under pressure entering said chamber through said inlet passage, output means operatively associated with said rotor and driven in response to rotation of said rotor, said housing including circular abutment valve chambers parallel with and opening into said rotor chamber, an abutment valve rotatably mounted in each of said abutment valve chambers, said rotor having three radially projecting displacement lobes and said abutment valves each having two radially directed sealing lobes engagable with said rotor between adjacent displacement lobes thereof during rotation of said rotor in said given direciton to seal against fluid flow from said inlet passage toward said outlet passage in a direction opposite said given direction, and radially outwardly displacable sealing means carried by said rOtor between said displacement lobes for sealing engagement with said abutment valve sealing lobes, said radially outwardly displacable sealing means including plate means extending circumferentially between adjacent displacement lobes and fluid actuated pressure applying elements radially inwardly of said plate means for displacing said plate means toward said abutment valve sealing lobes.

12. The hydraulic motor of claim 11, wherein said rotor includes a hub portion between said adjacent displacement lobes and said pressure applying means includes cylindrical pins disposed in corresponding longitudinally extending recesses in said hub portion, said plate means including fluid passageways opening between said recesses and the outer surface of said plate means.

13. The hydraulic motor of claim 12, wherein said recesses in said hub portion include a plurality of parallel spaced apart recesses having at least one wall thereof inclined relative to said plate means, said fluid passageways in said plate means including at least one opening communicating with each recess for flow of fluid under pressure thereinto.

14. The hydraulic motor of claim 12, wherein said sealing lobes have an outer surface movable in progressive engagement circumferentially across said plate means during rotation of said rotor in said given direction, said openings to said recesses being arranged in circumferentially spaced relation along said plate means and being sequentially uncovered by movement of said lobe outer surface across said plate means for said fluid under pressure to enter said recesses sequentially during said movement

15. A positive displacement device for fluids comprising housing means having rotor and abutment valve chambers, said rotor chamber including an arcuate wall and said abutment valve chamber including a circular wall intersecting said rotor chamber wall, cooperable rotatable rotor and abutment valve chambers, fluid inlet and oulet ports at spaced locations about said rotor chamber wall, said rotor comprising a hub and at least two lobes projecting radially outwardly from said hub, and fluid pressure actuated sealing means carried by said lobes and displaceable radially outwardly relative thereto for sealing engagemnet with said rotor chamber wall, said rotor chamber wall including a circular portion between said inlet and outlet ports and having a given radius with respect to the axis of said rotor chamber, said chamber wall further including a second portion adjacent said outlet port and merging with the corresponding end of said circular portion and divering with respect to said chamber axis, said sealing means in moving from said inlet port toward said outlet port engaging said second portion of said rotor chamber wall ahead of said outlet port to reduce the fluid pressure behind the corresponding one of said rotor lobes.

16. The positive displacement of claim 15, wherein said lobe has an outer end provided with a longitudinal extending recess opening radially outwardly of said end, and said sealing means includes a sealing element disposed in said recess and displacable outwardly of said recess opening for sealing engagement with said rotor chamber wall in response to fluid under pressure acting thereagainst in said recess.

17. The positive displacement device of claim 16, wherein said sealing element is a metal pin and said recess opening has a circumferential width less than the diameter of said pin, said outer end of said lobe and said rotor chamber wall being radially spaced such that said recess communicates with said rotor chamber when said pin engages said rotor chamber wall for fluid under pressure to enter said recess from said rotor chamber.

18. The positive displacement device of claim 17, wherein said recess includes opposed longitudinally extending side walls diverging inwardly from said recess opening.

Images