US3453966A

US3453966A - Hydraulic motor or pump device

Info

Publication number: US3453966A
Application number: US636126A
Authority: US
Inventors: Robert T Eddy
Original assignee: Reliance Electric and Engineering Co
Current assignee: Reliance Electric and Engineering Co
Priority date: 1967-05-04
Filing date: 1967-05-04
Publication date: 1969-07-08
Anticipated expiration: 1986-07-08
Also published as: DE1703346A1; BE714271A; GB1177733A; FR1565147A

Description

July 8, 1969 HYDRAULIC MOTOR OR PUMP DEVICE Filed May 4, 1967 Sheet of 5 INVENTOR.

ROBERT T. EDDY ATTORNEY y 8, 1969 R. T. EDDY HYDRAULIC MOTOR 0R PUMP DEVICE Sheet of 5 Filed May 4, 1967 FIG. 4

8 mm Cu INVENTOR.

ROBERT r. EDDY BY ATTORNEY V July 8; 1969 EDDY 3,453,966

I HYDRAULIC MOTOR on PUMP DEVICE Filed May 4, 1967 Sheet 3 of 5 INVENTOR.

08E RT T. E D DY A RNEY. V

' July '8, 1969 v R. 1-. E DY 3,453,966

HYDRAULIC MOTOR 0R PUMP DEVICE Filed May 4, 1967 Sheet 4 of 5 l1 ill/? INVENTOR.

ROBERT T. EDDY ATTORNEY J ly 1969 R. T. EDDY HYDRAULIC MOTOR 0R PUMP DEVICE Sheet Filed May 4, 1967 FIG.

INVENTOR.

ROBERT 1; EDDY BY ATTORNEY United States Patent 3,453,966 HYDRAULIC MOTOR 0R PUMP DEVICE Robert T. Eddy, South Bend, Ind., assignor to The Reliance Electric and Engineering Company, a corporation of Ohio Filed May 4, 1967, Ser. No. 636,126 Int. Cl. F04c 1/16, 1/02, 3/00 US. Cl. 103--130 20 Claims ABSTRACT OF THE DISCLOSURE Hydraulic motors and pumps utilizing inner and outer gerotor elements are extensively used in a variety of hydraulic systems, and in recent years the gerotor principle has been extensively used in motors and pumps in which the outer gerotor element is stationary and the inner gerotor element, normally having one less tooth than the outer element, is orbited within the outer element in meshing relation therewith. The inner orbiting element is connected by a universal joint to a rotating shaft serving as a force input or output member, depending upon whether the unit is being used as a motor or a pump. Inlet and outlet ports for the hydraulic fluid are synchronized with the expanding and contracting chambers between the lobes on the two gerotor elements by a rotary valve structure operated in accordance with the speed of the aforementioned shaft. The usual type of motor embodying the orbital principle, while having high torque output and high volumetric efliciency at low speeds, contains a valving structure and universal drive interconnecting the inner element with the output shaft of relatively complicated construction which is costly to manufracture and which lacks the necessary or desired compactness for an eflicient and effective compound multiplestage motor. Pumps involving the same valving arrangement and universal joint structure have the same inherent disadvantages as those present in motors of this type, along with the presence of a pulsating component in the delivery of fluid from the pump. It is therefore one of the principal objects of the present invention to provide a hydraulic motor or pump having an outer gerotor element and a plurality of inner gerotor elements, in which the force is transmitted directly between a central rotating shaft and the inner element without the use of a universal drive or complicated valving, and in which there is a smooth, non-pulsating flow of fluid.

Another object of the invention is to providea motor and pump structure having three or more gerotor elements, in which an inner non-orbiting gerotor element is meshed in driving or driven relation with an intermediate element, which in turn is meshed in driving or 3,453,966 Patented July 8, 1969 driven relation with the outer gerotor element, thus forming a compound motor or pump transmitting the driving or driven force directly to or from a single, non-orbiting rotating shaft mounted centrally in the motor or pump unit.

Still another object of the invention is to provide a relatively simple and compact orbital type gerotor motor or pump in which a rotating manifold contains constantly open fluid inlet and outlet ports communicating, respectively, with the expanding and contracting fluid chambers between the gerotor elements and continuously with fixed inlet and outlet passages in the motor or pump housing, and in which no valving is used to obtain proper and effective fluid flow to and from the appropriate chambers.

A further object is to provide a motor or pump structure of the aforesaid type involving the use of three or more gerotor elements in orbiting relationship to one another, which are driven relative to one another by direct mechanical force and/or by hydraulic fluid reac tion to produce a speed variation and mechanical advantage between two or more of the elements.

Another object is to provide a compound or multiple stage motor or pump of the gerotor type in which the one gerotor element is common to more than one operating stage or motor-pump unit.

Additional objects and advantages of the invention will become apparent from the following description and accompanying drawings, wherein:

FIGURE 1 is a plan view of the present motor or p p;

FIGURE 2 is a side elevational view of the motor or [FIGURE 3 is a cross-sectional view of the motor or pump shown in FIGURE 1, the section being taken on line 3-3 of the latter figure;

FIGURE 4 is a vertical cross-sectional view of the motor or pump, the section being taken on line 44 of FIGURE 3;

FIGURE 5 is a cross-sectional view of the motor or pump, taken on line 5-5 of FIGURE 3;

FIGURE 6 is a cross-sectional view taken on line 6--6 of FIGURE 3;

FIGURE 7 is a cross-sectional view taken on line 7-7 of FIGURE 3;

FIGURE 8 is a cross-sectional view taken on line 8--8 of FIGURE 5; and

FIGURES 9 and 10 are cross-sectional views of a modified form of a port plate used in a multiple stage motor or pump.

Referring more specifically to the drawings and to FIGURES 1, 2 and 3 in particular, numeral 10 designates generally a motor or pump having a housing 12 consisting of

outer sections

14 and 16 and

intermediate sections

18 and 20 interposed between the two outer sections and held firmly therebetween by a plurality of screws 22 extending through bores in the outer section 16 and two intermediate sections into threaded bores 24 in outer section 14, the screws retaining the four sections firmly together to form a unitary structure. The present hydraulic structure may be used equally as well for a motor or a pump, without alteration of the internal structure thereof, and this type has a wide variety of uses, particularly as a motor. However, for convenience of the description, the structure will be described with reference to its use as a hydraulic pump having fluid inlet port 26 and fluid outlet port 28 in housing section 14, the pump being driven by a motor connected to input shaft 30 journalled in

bearings

31 and 32 at the axial center of housing 12. The pump may be driven by a direct drive coupled to the shaft, or by a belt and a sheave mounted on said shaft and keyed thereto by a key and keyway in the outer end of shaft 30. In the event the device is used as a motor, the inlet 26 and outlet 28 may be either fluid inlet or outlet, and shaft 30 becomes a power output shaft. While the present mechanism is designed primarily for use with hydraulic fluids, it may be satisfactorily used in connection with other types of fluid, including water,

fuel and lubricating oil, these various uses and adaptations being considered Within the scope of the present invention.

The pump housing 12 contains a chamber 33 in which is disposed an internally toothed gerotor element 34 having thirteen teeth 36 defining the external wall of the pumping chamber. Element 34 is held securely in fixed position in chamber 33 and is concentric with shaft 30. Mounted on shaft 30 is an inner gerotor element 40 secured to the shaft for rotation therewith by a key 42 in keyways 44 and 46 in the inner element 40 and shaft 30, respectively, and having six external teeth 48. The inner element is substantially on a plane with the outer gerotor element; however, as shown in the drawings, it is offset axially for reasons more fully explained hereinafter. Interposed between outer element 34 and inner element 40 is an intermediate gerotor element 50 having teeth 52 on its outer peripheral surface and teeth 54 on its inner peripheral surface. The number of teeth 52 on the outer peripheral surface is one less than the number of internal teeth 36 on element 34. Likewise, the number of teeth on the inner periphery of element 50 is one more than the number of external teeth on inner element 40. There is also a relationship between the number of teeth 52 on the periphery of intermediate element 50 and external teeth 48 on inner element 40, the number on the latter element being one-half the number of teeth 52. Rotation of inner element 40 by shaft 30 causes teeth 48 of element 40 to engage the respective adjacent teeth 54 of element 50, thereby moving intermediate element 50 in an orbital cycle about the internal periphery of element 34. For each rotation of shaft 30 and inner element 40, element 50 completes four orbital cycles, and during each orbital cycle of intermediate element 50 driven by counterclockwise rotation of shaft 30 as viewed in FIGURE 4, cavities 60, consisting of one-half of the cavities defined by the internal periphery of element 34 and the external periphery of intermediate element 50, are expanding, and cavities 62, consisting of the remaining cavities between the two elements, are contracting, thus producing a pumping action with the expanding cavities 60 drawing in the fluid and the contracting cavities 62 expelling the fluid under pressure.

In the gerotor element arrangement just described, the expanding and contracting

chambers

60 and 62 shift around the internal periphery of element 34 as element 50 orbits within element 34. These expanding and contracting chambers are connected with inlet and

outlet ports

26 and 28, respectively, by a rotatable port plate 70 and annular passages 72 connected with inlet passage 26 and annular passage 74 connected with outlet passage 28. The port plate is freely rotatable on shaft 30 and within housing section 18, and is driven by engaging cam surface 76 on the intermediate gerotor element 50 and cam surface 78 on the port plate. Cam surface 76 on the intermediate element is concentric with the inner and outer peripheries of the element, and cam surface 78 is eccentric with respect to shaft 30 and center opening 80 through which the shaft passes and in which the shaft rotates. With passage 26 serving as the fluid inlet passage of the pump, the expanding cavities are connected through the port plate to annular passage 72 by arcuate slot 82, and a plurality of radially extending small passages 84 connecting the arcuate slot with an annular passage 86 around the periphery of the port plate, annular passage 86 being defined by the external periphery of the port plate, the internal periphery of housing section 18 and the corresponding side of housing section 20. Annular passage 86 communicates directly and continuously with passage 72 so that fluid enters the expanding cavities of the pump through inlet passage 26,

annular passages

72 and 86, radial holes 84 and arcuate slot 82. The contracting fluid cavities are connected with outlet passage 28 by arcuate slot 90,

annular grooves

92 and 93, each extending completely around one side of the port plate and communicating with annular passage 74, which, in turn, communicates with outlet passage 28. The cam on intermediate element 50 rotates the port plate at the orbital rate of the intermediate element so that slots 82 and are always synchronized with the expanding and contracting

cavities

60 and 62. The port plate is substantially balanced hydraulically on opposite sides by a passage 95 extending therethrough. If the shaft 30 is rotated in the opposite direction, inlet and

outlet ports

26 and 28 become outlet and inlet ports, respectively, and the fluid flows through the pump passages and slots in the opposite direction.

In the operation of the present device as a pump, if shaft 30 is driven in the counterclockwise direction as viewed in FIGURE 4, inner gerotor element 40 imparts an orbital movement to element 50, thereby expanding chamber 60 and contracting chambers 62 which orbit along with intermediate element 50. As element 50 moves through its orbital cycle, cam surface 76 on element 50 by engagement with cam surface 78 on port plate 70, causes the port plate to rotate at the orbital speed of element 50, thus maintaining slot 82 in synchronous relation with the expanding cavities 60 and slot 90 in synchronous relation with the contracting cavities 62. As the intermediate element 50 orbits and port plate 70 rotates, fluid is drawn in through inlet passage 26,

annular passages

72 and 74, and radial holes 84 to slot 82 and thence into the expanding cavities 60, and when these expanding cavities with the fluid become contracting cavities 62 the fluid is forced therefrom through slot 90, groove 93, annular passage 74 and outlet passage 28.

In order to use the device as a motor, the pressurized fluid is delivered to the present outlet passage 28 and then through the respective passages to cavities 62 which then become expanding chambers and cavities 60 become contracting chambers, discharging the fluid through the respective passages to present inlet passage 26 which becomes an outlet for the driving fluid. As this operation takes place, the fluid imparts an orbital movement to intermediate element 50 which in turn drives inner element 40 and shaft 30, which now becomes an output shaft for the motor.

In the embodiment of the invention illustrated in the drawings, the fluid pressure in the expanding and contracting cavities between the inner and

intermediate elements

40 and 50 is balanced through annular space 96 in chamber 33, the inner element being held, in its position on the shaft by a snap ring 98 on shaft 30. The inner gerotor element, which has one less tooth than the internal periphery of the intermediate element, provides a difference between the rotational speed of the intermediate element 50 and rotational speed of shaft 30, and, by increasing or decreasing the number of teeth on

elements

40 and 50 while maintaining a difierence of one tooth between these elements, various desired ratios in speed may be obtained between the intermediate element and the shaft.

The device, as shown in the drawings, may be modified to include a second or compound port plate as a part of the original port plate or as a separate port plate, containing inlet and outlet ports communicating with the expanding and contracting cavities between the inner element 40 and the intermediate element 50, thus resulting in a compound motor or pump in which the stages are arranged on substantially the same radial plane. A suit able compound motor or pump structure is illustrated in FIGURES 9 and 10 showing a port plate having the same passages and slots in the outer portion as port plate 70 and hence like numerals will be used to identify like parts in that portion of the plates. In the modified port plate 108, inner

arcuate slots

110 and 112 are connected by

passages

114 and 116 to

slots

82 and 90, respectively, and are in constant communication with the respective expanding or contracting cavities between

elements

40 and 50. In this embodiment a plate or other filler structure is employed to prevent communication between the expanding and contracting cavities through space 96 of chamber 33, so that the inner and intermediate gerotor elements form an effective motor or pump for augmenting the drive or output of the intermediate and outer gerotor elements described hereinbefore. For example, in using the device as a pump and assuming port 26 is the inlet, fluid is drawn through slot 110 into the expanding cavities between elements 40 and 50' and is forced therefrom by the contracting cavities through slot 112, passage 116 and slot 90 into outlet 28. This compound arrangement can be made without appreciably increasing the size of the pump housing and with only a small increase in the number of parts. While only two stages would be created by the arrangement described, additional stages may be added by following the basic concept described herein.

In both the original embodiment and in the modified form, the flow or fluid may be in either direction between

passages

26 and 28 depending upon the direction of rotation of shaft 30 when the device is used as a pump, and in either direction to give the desired direction of shaft rotation when the device is being used as a motor. Reference to passage 26 as an intake passage has been made merely for convenience in illustrating the construction and operation of the present device which may be used without modification as either a motor or pump.

Two embodiments of the present motor or pump have been described in detail herein; however, various other changes and modifications may be made without departing from the scope of the invention.

I claim:

1. A motor or pump device comprising a housing hav ing two fluid passages, an internally toothed outer gerotor element, an externally toothed inner gerotor element disposed within said outer gerotor element on a common axis therewith, an externally and internally toothed intermediate gerotor element disposed between said outer and inner gerotor elements for relative orbital movement in operative engagement therewith and forming expanding and contracting chambers therebetween, the number of external teeth on said intermediate and inner elements being less than the number of internal teeth on said outer and intermediate elements respectively, a shaft connected to said inner gerotor element, said inner gerotor element transmitting a driving force between said intermediate element and said shaft, and means for continually con necting a portion of the cavities between the outer and intermediate elements with one of said fluid passages and another portion of said cavities with the other of said fluid passages.

2. A motor or pump device as defined in claim 1 in which said outer gerotor element is fixed with respect to the housing and the inner gerotor element is rotatable on a fixed axis.

3. A motor or pump device as defined in claim 2 in which said inner gerotor element is mounted on a rotataable shaft journalled in said housing.

4. A motor or pump device as defined in claim 1 in which the number of external teeth on said intermediate gerotor element is one less than the internal teeth on the outer gerotor element.

5. A motor or pump device as defined in claim 1 in which the number of teeth on said inner gerotor element in one less than the number of internal teeth on said intermediate gerotor element.

6. A motor or pump device as defined in claim 1 in which the chambers between the outer and intermediate gerotor elements form fluid intake and output cavities and the chambers between the intermediate gerotor element and the inner gerotor element form cavities for fluid of substantially uniform pressure.

7. A motor or pump device as defined in claim 1 in which the means for continually connecting the cavities with the fluid passages consists of a rotatable generally disc-shaped port plate rotating at the orbital speed between said outer and intermediate gerotor elements.

'8. A motor or pump device as defined in claim 2 in which the means for continually connecting the cavities with the fluid passages consists of a rotatable generally disc-shaped port plate rotating at the speed of the orbital movement of said intermediate gerotor element.

9. A motor or pump device as defined in claim 7 in which said port plate includes two substantially diametrically opposed arcuate salts, and a passage connected to one of said arcuate slots and communicating with one of said fluid passages and a passage connected to the other of said slots and communicating with the other of said passages.

10. A motor or pump device as defined in claim 9 in which an annular passage in said housing is disposed around the periphery of said port plate and communicatingwith one slot, and a second annular passage in said housing is disposed along the side of said port plate and communicating with the other of said slots.

11. A motor or pump device as defined in claim 1 in which a means is included for continually connecting a portion of the cavities between the inner and intermediate gerotor elements with one passage and for continually connecting another portion of said cavities between the inner and intermediate gerotor elements with the other passage.

12. A motor or pump device as defined in claim 11 in which said outer gerotor element is fixed with respect to the housing and the inner gerotor element is rotatable on a fixed axis.

13. A motor or pump device as defined in claim 12 in which said inner gerotor element is mounted on a rotatable shaft journalled in said housing.

14. A motor or pump device as defined in claim 7 in which said port plate in driven by a. cam operatively connected to said intermediate gerotor element.

15. A motor or pump device as defined in claim 1 in which the inner gerotor element has one half as many external teeth as the intermediate gerotor element.

16. A motor or pump device as defined in claim 1 in which the means for continually connecting a portion of the cavities between the outer and intermediate elements with one of the fluid passages and another portion of said cavities with the other of said fluid passages includes a means for connecting a portion of the cavities between the inner and intermediate elements with one of said fluid passages and another portion of said cavities between the inner and intermediate elements with the other of said fluid passages.

17. A motor or pump device as defined in claim 1 in which a means is included for connecting a portion of the cavities between the inner and intermediate elements with one of said fluid passages and another portion of said cavities with the other of said fluid passages.

18. A motor or pump device as defined in claim 17 in which the means connecting the cavities between the inner and intermediate elements consists of a rotatable plate.

19. A motor or pump device as defined in claim 9 in which said port plate contains two additional substantially diametrically opposite arcuate slots within the confines of said first mentioned arcuate slots.

20. A motor or pump device as defined in claim 19 in which passages interconnect each inner arcuate slot with the opposite outer arcuate slot.

References Cited UNITED STATES PATENTS Feuerheerd 103-130 Charlson 103-131 XR Mosbacher 103-130 XR Huber 91-56 5 \VILLIAM L. FREEH, Primary Examiner.

WILBUR J. GOODLIN, Assistant Examiner.

US. Cl. X.R. 103-126