US3726356A - Hydraulic device - Google Patents

Abstract

A hydraulic motor-pump assembly including a housing, a chamber formed in the housing, a shaft journalled in the housing and extending into the chamber and a gear set in the chamber including an externally toothed rotor mounted fast on the shaft and an internally toothed stator assembly surrounding the shaft in meshing relation. The stator assembly is geared to the housing so as to cause, in response to relative rotation of the rotor, orbital movement of the stator assembly about the axis of the rotor and rotational movement of the stator assembly about its own axis at a speed less than the speed of rotation of the rotor. Certain passages, ports and the like are provided in the housing and in the stator assembly for directing high and low pressure fluid to and from the expanding and contracting fluid pockets formed between the teeth of the stator assembly in a manner providing high operating efficiency. The motor-pump assembly has wide application including use in a vehicular hydraulic motor drive arrangement.

Description

United States Patent [191 Goff et a1.

[ HYDRAULIC DEVICE [75] Inventors: Raymon L. Goff; Frederick D. Vennble, both of Lafayette, Ind.

73 Assignee: T n w Inc., Cleveland, Ohio [22] Filed: Feb. 1, 1971 [21] Appl. No.: 111,190

Related 1.1.8. Application Data [62] Division of Ser. No. 841,405, July 14, 1969, Pat. No.

[52] US. Cl ..l80/66 F [51] llnt. C1. ..B60k 7/00 [58] Field of Search ..l80/66 F, 44 F, 44 M, 180/66; 418/61 [56] References Cited UNITED STATES PATENTS 3,302,741 2/1967 Brazuk 180/66 F X 3,391,608 7/1968 Huber ..418/61 X 3,490,383 1/1970 Parrett ..418/61 X 2,989,951 6/1961 Charlson ..418/61 X 2,418,123 4/1947 Joy ..l80/66 F 2,679,300 5/1954 Nubling ..180/66 R 3,627,454 12/1971 Goff et al. ..418/61 Apr. 10, 1973 Primary ExaminerBenjamin Hersh Assistant Examiner-Milton L. Smith Attorney-Carlton Hill et al.

[57] ABSTRACT A hydraulic motor-pump assembly including a housing, a chamber formed in the housing, a shaft journalled in the housing and extending into the chamber and a gear set in the chamber including an externally toothed rotor mounted fast on the shaft and an internally toothed stator assembly surrounding the shaft in meshing relation. The stator assembly is geared to the housing so as to cause, in response to relative rotation of the rotor, orbital movement of the stator assembly about the axis of the rotor and rotational movement of the stator assembly about its own axis at a speed less than the speed of rotation of the rotor. Certain passages, ports and the like are provided in the housing and in the statorassembly for directing high and cation including use in a vehicular hydraulic motor drive arrangement,

5 Claims, 12 Drawing figures PATENTLD 1 @1973 3.726355 sum 6 BF 8 2 5 I N VENTORS Pay 401v A. 60 FF FREDERICK O. 1/6/V4646 PATEHTED 015175 726,356

sum 7 OF 8 M INVENTORS RA 7M0 Z. GoFF FR 062?, 0.14%; By ATTORNEYS HYDRAULIC DEVICE CROSS REFERENCE TO RELATED APPLICATIONS This application is a division of application Ser. No. 841,405 filed July l4, l969, now US. Pat. No. 3,627,454.

BACKGROUND OF THE INVENTION This invention relates generally to the field of hydraulic motor-purnp assemblies and more particuthe rotor in meshing relation. The rotor generally has one less tooth than does the stator and the teeth of both gears are so configured that in response to relative rotation of the gears the axis of one will orbit about the axis of the other. This relative rotational and orbital movement of the gears causes sequentially alternately expanding and contracting fluid pockets to be formed between the teeth of the stator.

A rotatable work input-output shaft is connected to a rotatable one of the gerotor gears, and when the assembly is used as a motor, high pressure fluid is directed to the expanding fluid pockets and low pres sure fluid is directed from the contracting fluid pockets, thereby causing rotation of the shaft. Corresponding'ly, when the assembly is used as a pump, the shaft itself is rotated, thereby drawing low pressure fluid to the expanding fluid pockets and expelling higher pressure fluid from the contracting fluid pockets.

Fluid is directed into and out of the expanding and contracting pockets by virtue of valve means which may include one or both of the gerotor gears. The valve means operates in timed relation to'the movement of the gears and for that reason may be referred to conveniently as commutation means.

Numerous arrangements of gerotor gear sets are known in the prior art. In some arrangements the stator is held stationary while the rotor both rotates and orbits. In other arrangements the rotor remains stationary while the stator both rotates and orbits. In still other arrangements one of the gears rotates while the other orbits.

In all of these arrangements the commutation means must be effective to direct the fluid into and out of the expanding and contracting fluid chambers in timed relation with the movement of the gears.

Gerotor gear sets and hydraulic pump-motor assemblies which incorporate such gear sets may be more suitable for certain applications than for others. The motor-pump assembly of the present invention, for example, has particular utility in the field of vehicular drive mechanisms as a result of its high torque and high operating efficiency capabilities.

SUMMARY OF THE INVENTION The present invention may be summarized as comprising a hydraulic motor-pump assembly which includes a gerotor gear set constructed and arranged so that the axis of the rotor remains aligned with the axis of the work input-output shaft while the stator assembly rotates relative to the rotor and the axis of the stator assembly orbits about the axis of the rotor. The commutation means includes the stator assembly in which certain pas sages, ports and the like are formed to direct the fluid into and out of the expanding and contracting fluid pockets in timed relation to the relative movement of the gerotor gears. The stator assembly is geared to the housing of the motor-pump assembly in a manner whereby the stator assembly rotates relative to the housing at a speed much less than the orbital speed of the stator assembly, as will be understood by those skilled in the art.

The commutation means provides what is referred to herein as phase-shift commutation. By the term phase-shift is meant that the control of commutation of high and low pressure fluid with the expanding and contracting fluid pockets is accomplished by controlling the opening and closing of fluid flow ports located respectively, relative to the axis of the rotor, in angularly offset relation to the fluid pockets into and out of which they control the flow of fluid.

An object of the present invention is to provide a highly efficient, high torque hydraulic motor-pump assembly that is relatively inexpensive in manufacture, has utility in a wide variety of applications and is particularly suited in vehicular fluid motor drive arrangements.

In such vehicular drive applications the housing of the assembly may be mounted fast to the frame of the vehicle and the wheel mounted for joint rotation on the work output shaft. On the other hand, the shaft may be connected fast to the vehicle frame and the wheel connected in fixed assembly to the housing of the assembly. The former application is particularly suited for higher vehicular speed whereas the latter application is particularly suited for higher torque, lower speed applications.

Several embodiments of a stator assembly constructed in accordance with the principles of the present invention are illustrated herein. Each of these embodiments may have particular utility in certain applications and may advantageously utilize different modes of construction and fabrication.

Other objects, features and advantages of the present invention will be readily apparent from the following description of certain preferred embodiments thereof, taken in conjunction with the accompanying drawing, although variations and modifications may be effected without departing from the spirit and scope of the novel concepts of the disclosure.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a cross-sectional view of a hydraulic motorpump assembly constructed in accordance with the principles of the present invention.

FIGS. 2, 3 and 4 are cross-sectional views taken along lines II--II, III-Ill and IV-IV in FIG. 1.

FIG. 5 is a cross-sectional view of another embodiment of a hydraulic motor-pump assembly constructed in accordance with the principles of this invention.

FIG. 6 is similar to FIGS. 1 and 5 and illustrates yet another embodiment of a motor-pump assembly constructed in accordance with the present invention.

FIGS. 7-10 are cross-sectional views taken along lines VIIVII, VIII-VIII, IX-IX and X--X in FIG. 6.

FIG. 11 is a cross-sectional view of a vehicular motor-drive arrangement including a hydraulic motorpump assembly similar to that as shown in FIG. 1., the housing of the assembly being connected fast to the frame of the vehicle and the shaft of the assembly rotatably mounting a wheel.

FIG. 12 is a cross-sectional view of another vehicular motor-drive arrangement in which the wheel is mounted on the housing of the motor-pump assembly and the shaft is connected fast to the frame of the vehicle.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS. 1-5, a hydraulic motor-pump assembly constructed in accordance with the principles of the present invention is indicated generally at reference numeral 10. The assembly comprises a housing 11 having a body portion 12, an annular spacer member 13 and an end cap 14. An end wall 16 of the body 12 faces a spaced parallel end wall 17 of the end cap 14 which, together with a cylindrical wall 18 of the spacer member 13, forms a cylindrical chamber 19 within the housing 11.

A work input-output shaft 20 is journalled in the housing 11 by means of bearing assemblies 21 and 22 and is axially aligned with the chamber 19. When the assembly 10 is being utilized as a pump the shaft 20 may be connected to suitable drive apparatus and serves as a work input shaft. On the other hand when the assembly 20 is being utilized as a motor the shaft 20 may be coupled to suitable driven apparatus and serves as a work output shaft. An outer end 23 of the shaft 20 may be splined as at 24 or otherwise adapted for suitable connection to the driving or driven apparatus. A suitable seal assembly as indicated at reference numeral 26 is provided near the outboard end of the shaft 20 to prevent loss of fluid from the housing 11 past the shaft 20.

Disposed within the chamber 19 is a gear set indicated generally at reference numeral 27 which, when the assembly 10 is being utilized as a hydraulic pump, is operated by the shaft 20 to increase fluid pressure thereacross. Conversely, when the assembly 10 is being utilized as a hydraulic motor drive pressurized fluid acts on the gear set 27 to rotate the work output shaft 20.

The gear set 27 comprises a pair of gear members 28 and 29. The gear member 28 is mounted fast to the shaft 20 for joint rotation therewith by means of a spline connection including a splined portion 30 of the shaft 20 and a splined bore 31 of the gear member 28.

Formed on an outer wall 32 of the gear 28 are a series of gear teeth 33 which, in the embodiment of the invention illustrated in FIGS. l-5, are six in number. Since the gear member 28 rotates on a fixed axis it is conveniently referred to herein as a rotor.

The gear member 29 surrounds the rotor 28 in the chamber 19 and comprises an inner cylindrical wall 34 and an outer cylindrical wall 36. A series of cylindrically shaped recesses 37 are formed in the inner wall 34 and disposed within each is a tubular member 38. Since the walls of the recesses 37 envelop the periphery of the tubular members 38 through an are greater than 180 the members 38 are'securely maintained within their respective recesses 37.

The tubular members 38 serve as gear teeth for the gear member 29 and are greater in number by one than the teeth 33 of the rotor 28. Because of this difference in number between the teeth 33 of the rotor 28 and the mating teeth 38 of the gear member 29 rotation of the rotor 29 about its fixed axes has the effect of causing the gear member 29 to move in an orbital fashion about the rotor 28 or both orbit and rotate about the axis of the rotor 28. As a result of this orbital path of travel the outer gear member 29 is conveniently referred to herein as a stator assembly. Gear sets employing an externally toothed gear member and an internally toothed gear member surrounding the externally toothed member, in which the number of internal teeth exceeds by one the number of external teeth, are often referred to by those skilled in the art as gerotor gear sets, one of the peculiar characteristics of which involves the relative movement thereof whereby, aupon rotation of either one, the gear members both orbit and rotate relative to one another. The ratio of relative orbital speed to rotational speed of the gear members is equal to n+l where n equals the number of external teeth of the inner gear member.

In the embodiment illustrated in FIGS. 15 the stator assembly 29 of the gerotor gear set 27 comprises a series of gear teeth 39 found on the outer peripheral wall 36 thereof. A cooperating series of teeth 40 is formed on the cylindrical wall 18 of the spacer portion 13. The number of teeth 40 exceeds the number of teeth 39 to the end that, as the stator assembly 29 orbits about the rotor 28, that is, as the axis of the stator assembly 29 moves about the axis of the rotor 28 in a circular path of travel, the stator assembly 29 will also rotate relative to the housing '11.

In the embodiment-illustrated the gear teeth 39 equal 52 in number whereas the gear teeth 40 equal 54 in number. Thus for each complete movement of the stator assembly 29 through an orbital path of travel the stator assembly 29 will rotate in the housing 11 2/54 or l/27 of a revolution about its own axis.

As the gear members 28 and 29 rotate and orbit relative to one another the gear teeth 33 and 38 form sequentially alternately expanding and contracting fluid pockets between the teeth 38 of the stator assembly 29. These fluid pockets are indicated respectively in FIG. 3 at reference characters 41,,-41,,.

To illustrate this principle, assume the rotor 28 is rotated in a counterclockwise direction as indicated by the arrow 42 in FIG. 3. The fluid pocket 41,, will thereby be contracted or reduced in volume from that which would be indicated in FIG. 3. Similarly fluid pockets 41,, and 41,. would tend to become reduced in volume.

On the other hand fluid pockets 41,,, 41 and 41, would tend to increase in volume. Fluid pocket 41,, would tend to vary little in volume until the rotor 28 had turned through a substantial number of degrees since the gear tooth 33 disposed therewithin initially varies its position initially at a slower rate than the remaining gear teeth 33.

Meanwhile such counterclockwise rotation of the rotor 28 causes the stator assembly 29 to tend to orbit in a clockwise direction at an orbital speed six times greater than the rotational speed of the stator 28. However, as the stator assembly 29 orbits in a clockwise direction the gear teeth 39 and 40 cause rotation of the stator assembly 29 in a counterclockwise direction.

' Thus in the disposition of the parts shown in FIG. 3, for each complete revolution of the rotor 28 about its axis the stator assembly 29 will orbit six times, and for each movement of the stator assembly 29 through one complete orbital path of travel it will rotate 1/27 of a revolution about its axis relative to the housing 11. The fluid which acts upon or is acted upon by the hydraulic motor-pump assembly enters and leaves the housing 11 through a pair of openings indicated at reference numerals 43 and 44, both of which may be threaded to conveniently receive suitable fluid conduits. When the assembly 10 is being utilized as a motor the direction of rotation of the work output shaft will be determined by which of the openings 43 and 44 is connected to the high pressure side of the main fluid power pump and which is connected to the low pressure side of the main pump. The direction of rotation of the shaft 20 may be reversed simply by reversing the connections of the openings 43 and 44 to the main power pump.

On the other hand when the assembly 10 is being utilized as a hydraulic pump the direction of rotation of the work input shaft 20 determines which of the openings 43 and 44 will receive the low pressure fluid and which will discharge the higher pressure fluid to the intended point of use. v

' When the assembly 10 is being utilized as a hydraulic motor it is necessary that the high pressure fluid be directed to the expanding fluid pockets 4l,,-41,, whereas when the assembly 10 is being utilized as a pump the contracting fluid pockets communicate with that one of the openings 43 and 44 delivering the high pressure fluid from the assembly 10. The fluid acting upon or being acted upon by the motor-pump assembly 10 is directed to and from the expanding and contracting fluid pockets 41 -41,, in timed relation to the rotational and orbital movement of the gear members 28 and 29 by means including the stator assembly 29 and referred to generally as commutation means. The fluid such as oil or the like is conducted by means of fluid passages 43,, and 44,, from the openings 43 and 44 to a pair of annularly shaped grooves 43,, and 44,, formed in the radial wall 16 of the chamber 19. The grooves 43,, and 44,, are separated from each other by a ridge or land 46 as shown in FIGS. 1 and 2.

The stator assembly 29 comprises a stator member 29,,, the axial dimension of which corresponds to the axial dimension of the rotor 28 and of the tubular members 38, and a spacer plate 29,. The spacer plate 29,, is firmly secured to the stator 29,, by means of a plurality of suitable fasteners such as rivets indicated at reference numeral 47. One radial wall 48 of the spacer plate 29,, engages in sliding relation with the radial wall 16 of the housing body member 12 whereas an opposite wall 49 abuts an adjacent side wall 50 of the stator member 29,, and engages in sliding relation a corresponding side wall 51 of the rotor 28.

Since the spacer plate 29,, moves jointly with the stator member 29,, it is apertured as 52 to accommodate orbital movement around the shaft 20. The diameter of an outer peripheral wall 53 of the spacer plate 29,, is

spacer plate 29,. Communicating with the apertures curved fluid flow passageways 56,,-56,, which are formed in the face of the end wall 50 of the stator member 29,, and open respectively to their corresponding fluid pockets 41,,-4l,, through ports 57,,-57,,.

The triangularly shaped apertures 54,-54, are angularly offset from their respective ports 57,,57,, (and thus the fluid pockets 41,41, with which they respectively communicate) by about 90 with respect to the axis of the stator assembly 29. This angularly offset relation serves to provide the commutation system referred to herein as phase-shift commutation.

To further explain, reference is made to the relative disposition of parts shown in FIGS. 3 and 4 wherein the axis of the stator assembly 29 is vertically aligned with respect to the axis of the rotor 28. Assuming that the motor-assembly 10 is being utilized as a hydraulic motor and that the shaft 20 is to be rotated in the direction indicated by the arrow 42, the pressurized fluid from the discharge side of the main power pump to which the assembly 10 is connected will be coupled to the fluid opening 43 and the return side of the main power pump coupled to the fluid opening 44. The groove 43,, is therefore subjected to high pressure fluid and the groove 44,, subjected to low pressure fluid.

In the position of the parts shown in FIGS. 3 and 4 the stator assembly 29'must orbit counterclockwise to rotate the shaft 20 counterclockwise, and to accomplish this result it is preferable for the commutation system to provide for communication of all of the fluid pockets on the right-hand side of the axis of the stator assembly 29 (all of the expanding fluid pockets 41,,-41,, with high pressure fluid to apply maximum motive forces to the stator assembly 29, and as a result thereof, to the rotor 28.

Phrased differently, maximum force is applied to the stator assembly 10 when all of the fluid pockets 4l,,-4l located on one side of a line extending through the axis of the rotor 28 and the point at which the stator assembly 29 contacts the cylindrical wall 18 of the chamber 19 communicates with high pressure fluid and all of the remaining fluid pockets 4l,,41,, communicate with low pressure fluid.

In FIG. 3 the grooves 43,, and 44,, and the land 46 have been indicated in phantom lines to indicate the substantially the same as the diameter of the outer wall relative positions thereof when the stator assembly 29 is in the uppermost position thereof as shown in FIGS. 3 and 4. Since the relative orbital movement and rela-' tive positions of the stator assembly 29 and the stationary grooves 43,, and 44,, determine which of the grooves 43,, and 44 communicates with each of the fluid pockets 4l,,4l,,, the angular offset relation between the fluid pockets 41,41, (and accordingly the ports 57,,57,,) and the triangularly shaped apertures 54,,54 in the spacer plate 29,, (referred to herein as phase-shift commutation) assures maximum input, output and efficiency of the motor-pump assembly 10.

The embodiment illustrated in FIG. 5 is similar to that shown in FIGS. l-4, the principal differences being that the low and high pressure fluid are supplied to and discharged from both of the axially spaced ends of the fluid pockets, rather than from only the right end of the pockets as obtains in the FIGS. 1-4 embodiment. Since many of the individual parts of the embodiment shown in FIG. are similar or identical to corresponding parts shown in FIGS. 14 the same reference numerals will be used for corresponding parts only increased by the number 100.

Thus in FIG. 5 the motor-pump assembly 100 comprises a pair of fluid openings 143 and another pair of fluid openings 144. Each of the fluid openings 143 communicates through a corresponding passage 143,, to an annular groove 143,,, one of which is formed in the radial wall 116 of the body member 112 and the other of which is formed in the radial wall 117 of the housing end cap 114.

The stator assembly 129 includes a single stator member 129,, but a pair of spacer plates 129,, are located respectively on opposite sides of the stator member 129,,. A series of triangularly shaped apertures 154,,154,, are formed in each of the spacer plates 129,, and a series of elongated fluid flow passages 156,,156,, are formed in each of the end walls 150 and 150' of the stator member 129,,.

The provision of the dualfluid openings 143 and 144, the two sets of grooves 143, and 144,, as well as the duplication of the other portions of the commutation means serve to reduce pressure losses through the assembly 10, increase overall efficiency and performance characteristics and reduce wear and prolong the useful life of the assembly by axially balancing the fluid pressure generated forces acting on the gerotor gear set 127.

Another embodiment of a hydraulic motor-pump assembly constructed in accordance with the principles of the present invention is illustrated in FIGS. 6-10 wherein reference numerals indicating parts similar to those included in the former two embodiments are indicated by similar reference numerals in the 200 series.

In the embodiment shown in FIGS. 6-10 the stator assembly 229 comprises a stator member 229,, and a pair of spacer members 229,, disposed on axially opposite sides of the stator member 229,, Sandwiched in between the stator member 229,, and the pair of spacer plates 229,, are a pair of stator plates 229,. The stator plates 229, are securely fastened to the stator member 229,, by a plurality of fasteners as indicated on the reference numeral 58.

In this embodiment the apertures in the spacer plate 229,, which register alternately with the high and low pressure grooves 243,, and 244 are flatter and more circumferentially elongated than the triangular apertures 54,,54 of the FIGS. 1-4 embodiment. Furthermore the elongated fluid flow passageways 256,, and 256,, are formed in the faces of flat radial walls 59, 59 of the stator plates 229,, 229,, rather than in the face or faces of the stator member 229,.

Furthermore the ports 257,,257,, which communicate with the expanding and contracting fluid pockets 241,,-241,, are formed in radial walls 60, 60 of the stator plates 229,, 229,, rather than in the inner wall 34 of the stator member 29,,, as is found in the FIGS. 1-4 embodiment.

The fluid openings 243 and 244 are found in the end cap 214 rather than in the body portion 212 and communicate 9 with the annular grooves 243,, and 244,, formed in the radial wall 217 of the end cap 214.

Another pair of grooves 243,, and 244,, are formed in the face 216 of the body portion 212. The two outer grooves 243,, communicate with one another between the outer peripheral wall of the stator assembly 229 and the cylindrical wall 218 of the chamber 219.

The pair of reduced diameter grooves 244,, communicate with one another through a series of radially extending passageways 61 also formed in the radial walls 216 and 217 of the body portion 212 and the end cap 214 and radial passages 62 and an interconnecting axial passage 63 formed in the input-output shaft 220.

Thus the embodiment shown in FIGS. 6-10 includes commutation means for directing the high and low pressure fluid to and from the expanding and contracting fluid pockets 24l,,241,, from axially opposite sides of the rotor 228 and the stator member 229,, even though there is only a single pair of fluid openings 243 and 24-4. In addition, the fluid is directed into and out of the fluid pockets 241,,241,, axially through the axially facing ports 257,,257,,, rather than the radially facing ports 57,,-57,, of the FIGS. 14 embodiment.

FIG. 11 discloses an embodiment of the hydraulic motor-pump assembly shown in FIGS. 1-4 adapted for utilization in a vehicular drive system. A portion of the frame of the vehicle on which the assembly 10 is mounted is indicated at reference numeral 66, and the end cap 14 is secured fast to the frame 66 by means ofa plurality of suitable fasteners such as the nuts and bolts indicated at 67 and 68 respectively.

The shaft 20, which in this application serves as a work-output shaft, is slightly axially tapered as indicated at 69 and keyed as at 70 to receive the hub 71 of a wheel 72 of the vehicle. The fluid openings 43 and 44 are connected to the high and low pressure sides ofa main power fluid pump, preferably through a valving mechanism enabling the direction of rotation of the shaft 20 to be reversed without reversing the operating direction of the main power pump. Accordingly, when the assembly 10 is connected to the main pump the wheel 70 will be rotated relative to the frame 66 by virtue of the relative orbital and rotational movement of the gears of the gerotor gear set 27 and as a result of the rotation of the shaft 20.

FIG. 12 is expositive of another embodiment of a hydraulic motor-pump assembly constructed in accordance with the principles of the present invention and utilized in a vehicular drive system. Since many of the components of the motor-pump assembly correspond closely or identically to those found in FIGS. 14 such corresponding parts or components will be given similar reference numerals although increased to the 300 series.

In this embodiment the housing 311 of the motorpump assembly 310 is securely connected to the rim 371 of the vehicular wheel 372 by virtue of a plurality of fasteners indicated at reference numerals 73. On the other hand the shaft 320, through an extension 74 thereof, is securely fastened to the vehicular frame 366, whereby the shaft 320 is maintained in a fixed or stationary relation with respect to the frame 366.

Thus in the FIG. 12 embodiment of the invention the housing 311 rotates on a fixed axis rather than the shaft 320, which remains stationary. The fluid openings 343 and 344, rather than being formed in the rotating housing 311, are formed in the extension 74 of the fixed shaft 320, and communicate by virtue of fluid passages 76 and 77 formed in the shaft 320 and corresponding passages 78 and 79 formed in the body portion 312 to the annular grooves 343,, and 344,, formed in the radial wall 16 of the body portion 312.

It will be appreciated by those skilled in the art that all of the various embodiments of the motor-pump as sembly disclosed herein are suitable for use in the vehicular drive arrangement as disclosed in FIGS. 11 and 12. In addition, of course, all of the illustrated embodiments may be advantageously utilized in a wide variety of fields of use.

What we claim is:

l. A hydraulic motor drive mechanism for vehicles comprising a housing adapted to be mounted fast on the frame of the vehicle and having means forming a gear chamber therein and a shaft journalled thereon extending into said chamber,

a wheel mounted on said shaft for joint rotation,

a gear set in said chamber including an externally I toothed rotor mounted fast on said shaft for joint rotation and an internally toothed stator assemblysurrounding said rotor and orbitally and rotationally movable relative thereto for providing alternately expanding and contracting fluid pockets between the teeth of said stator-assembly, fluid-conducting means for communicating high and low pressure fluid to said chamber, means formed on said stator assembly and on said housing for restraining said stator assembly against rotation at the rotational speed of said rotor and for guiding said stator assembly in said orbital movement, and i phase-shift commutation means including said stator assembly disposed in said chamber for directing fluid between said fluid conducting means and said expanding and contracting fluid pockets in response to orbital and rotational movement of said stator assembly relative to said rotor and in timed relation therewith,

said chamber-forming means comprising a stationary radial wall, said stator assembly comprising a radial wall in sliding engagement with said chamber radial wall, and said phase-shift commutation means comprising a pair of radially spaced concentric annular grooves formed in-the face of the stationary radial wall of said chamber in axial alignment with said shaft and a series of ports formed in the radial wall of said stator assembly and arranged in circular pattern to register sequentially and alternately with said grooves in response to orbital movement of said stator assembly.

2. The invention as defined in claim 1 wherein said fluid conducting means comprises a fluid inlet opening and a fluid outlet opening formed in said housing.

3. A vehicular hydraulic motor drive mechanism comprising a pair of relatively movable members including a housing and a shaft journalled for rotation on a fixed axis on said housing,

said housing having means including a stationary radial wall forming a gear chamber,

said shaft extending into said chamber,

a fluid inlet opening and a fluid outlet opening formed in said motor drive mechanism, a gear set in said gear chamber including an externally toothed rotor mounted on said shaft for joint rotation therewith on said fixed axis and an internally toothed stator assembly surrounding said rotor and movable orbitally and rotationally relative thereto to provide a series of sequentially alternately expanding and contracting fluid pockets between the internal teeth of said stator assembly,

means interconnecting said stator assembly and said housing for restraining said stator assembly against rotation at the rotational speed of said rotor and for guiding said stator assembly in said orbital movement, means including first and second radially spaced concentric annular grooves formed in the face of said stationary radial wall and communicating respectively with said fluid inlet opening and said fluid outlet opening,

fluid communication means including said stator assembly for communicating said expanding fluid pockets with one of said grooves and said contracting fluid pockets with the other of said grooves during relative orbital and rotational movement of said rotor and said stator assembly, and a wheel mounted fast on one of said relatively movable members,

the other of said relatively movable members being adapted for connection in fixed assembly to the frame of the vehicle.

4. The invention as defined in claim 3 wherein said housing is connected in fixed assembly to said frame and wherein said fluid inlet opening and said fluid outlet opening are formed in said housing.

5. The invention as defined in claim 3 wherein said shaft is connected in fixed assembly to the frame of said vehicle and said fluid inlet opening and said fluid outlet opening are formed in said shaft.

Claims (5)

1. A hydraulic motor drive mechanism for vehicles comprising a housing adapted to be mounted fast on the frame of the vehicle and having means forming a gear chamber therein and a shaft journalled thereon extending into said chamber, a wheel mounted on said shaft for joint rotation, a gear set in said chamber including an externally toothed rotor mounted fast on said shaft for joint rotation and an internally toothed stator assembly surrounding said rotor and orbitally and rotationally movable relative thereto for providing alternately expanding and contracting fluid pockets between the teeth of said stator assembly, fluid-conducting means for communicating high and low pressure fluid to said chamber, means formed on said stator assembly and on said housing for restraining said stator assembly against rotation at the rotational speed of said rotor and for guiding said stator assembly in said orbital movement, and phase-shift commutation means including said stator assembly disposed in said chamber for directing fluid between said fluid conducting means and said expanding and contracting fluid pockets in response to orbital and rotational movement of said stator assembly relative to said rotor and in timed relation therewith, said chamber-forming means comprising a stationary radial wall, said stator assembly comprising a radial wall in sliding engagement with said chamber radial wall, and said phase-shift commutation means comprising a pair of radially spaced concentric annular grooves formed in the face of the stationary radial wall of said chamber in axial alignment with said shaft and a series of ports formed in the radial wall of said stator assembly and arranged in circular pattern to register sequentially and alternately with said grooves in response to orbital movement of said stator assembly.

2. The invention as defined in claim 1 wherein said fluid conducting means comprises a fluid inlet opening and a fluid outlet opening formed in said housing.

3. A vehicular hydraulic motor drive mechanism comprising a pair of relatively movable members including a housing and a shaft journalled for rotation on a fixed axis on said housing, said housing having means including a stationary radial wall forming a gear chamber, sAid shaft extending into said chamber, a fluid inlet opening and a fluid outlet opening formed in said motor drive mechanism, a gear set in said gear chamber including an externally toothed rotor mounted on said shaft for joint rotation therewith on said fixed axis and an internally toothed stator assembly surrounding said rotor and movable orbitally and rotationally relative thereto to provide a series of sequentially alternately expanding and contracting fluid pockets between the internal teeth of said stator assembly, means interconnecting said stator assembly and said housing for restraining said stator assembly against rotation at the rotational speed of said rotor and for guiding said stator assembly in said orbital movement, means including first and second radially spaced concentric annular grooves formed in the face of said stationary radial wall and communicating respectively with said fluid inlet opening and said fluid outlet opening, fluid communication means including said stator assembly for communicating said expanding fluid pockets with one of said grooves and said contracting fluid pockets with the other of said grooves during relative orbital and rotational movement of said rotor and said stator assembly, and a wheel mounted fast on one of said relatively movable members, the other of said relatively movable members being adapted for connection in fixed assembly to the frame of the vehicle.

4. The invention as defined in claim 3 wherein said housing is connected in fixed assembly to said frame and wherein said fluid inlet opening and said fluid outlet opening are formed in said housing.

5. The invention as defined in claim 3 wherein said shaft is connected in fixed assembly to the frame of said vehicle and said fluid inlet opening and said fluid outlet opening are formed in said shaft.

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