US 3011449 A
Description (OCR text may contain errors)
Dec. 5, 1961 w. ERNST VANED HYDRAULIC UNIT INVENTOR.
3 Sheets-Sheet 1 Filed April 15, 1960 w. ERNST VANED HYDRAULIC UNIT Dec. 5, 1961 5 Sheets-Sheet 2 Filed April 15, 1960 Dec. 5, 1961 w. ERNST VANED HYDRAULIC UNIT Filed April 15, 1960 3 Sheets-Sheet- 5 INVENTOR.
' W417i? [EA/ST ZwAm/M United States Patent Ofifice 3,011,449 Patented Dec. 5,-1961 Ohio Filed Apr. 15, 1960, Ser. No. 22,566 3 Claims. (Cl. 103136) This invention relates to hydraulic pumps and motors and is particularly concerned with an improved construction for hydraulic pumps and motors'which will operate at increased efiiciency over heretofore known hydraulic units of this nature.
Hydraulic pumps and motors are fluid displacement units substantially interchangeable and one well known type of hydraulic pump or motor is the type utilizing vanes mounted in a slotted rotor with the rotor rotating inside a stator. It is in connection with this particular type of hydraulic unit that the present invention is concerned.
Vane type hydraulic units have certain inherent disadvantages over piston type units in that in the usual vane type unit the vanes slide continuously over the surface of the bore in the stator in which the rotor is mounted thus leading to considerable friction and the possibility of the tips of the vanes or the inside of the stator galling or there being wear at an unduly high rate.
Another disadvantage encountered in connection with vaned type hydraulic units is that the projected area of the rotor and stator under pressure is quite large thus leading to extremely high thrusts on the stator.
Having the foregoing in mind, it is a primary object of the present invention to provide a vaned hydraulic unit such as a pump or motor in which the friction between the vanes and the stator surface over which they slide is greatly reduced.
A still further objectof this invention is the provision of a vaned pump or motor unit in which the possibility of the vanes galling the inside surface of the stator is greatly reduced.
A still furtherobject is the provision of a vaned hy-, draulic unit such as a pump or motor in which the lateral forces on the stator on account of pressures therein are substantially balanced out.
These and'other objects and advantages will become more apparent upon reference to the drawings in which:
FIGURE 1 is a plan view showing. a hydraulic unit according to this invention; 1
FIGURE 2 isan explodedperspective view showing the unit;
FIGURE 3 is a vertical sectional view indicated by line 33 on FIGURE 1;
FIGURE 4 is a transverse sectional view indicated by line 44 on FIGURE 3;
FIGURE 5 is a transverse sectional view indicated by line 55 on FIGURE 3; 1 1
FIGURE 6 is still another transverse sectional view indicated by line 6-6 on FIGURE 3;
FIGURE? is a plan sectional view indicated by line 77 on FIGURE 5; and
FIGURE Sis a diagrammatic representation of a typical hydraulic circuit in. which a unit accordingto this invention can be placed. Y Y a Referring to the drawings more in detail, a pump or motor according .to this invention comprises an outer body part consisting of .the heads 10 and 12 andinter-v l 2 a posed therebetween is an annular center ring 14 sealedto the beads by sealing rings 16. The heads are intercon: nected by the through bolts 18.
Each head has a recess therein in. which there is mounted a wear plate 20in the head 10 and 22 in the head 12. These :Wear plates are located by the dowel pins 24 and are ported for supplying fluid to the vaned rotor.
Positioned between plates 20 and 22 and inside ring 14 is the stator ring 26 which, as will be seen in FIGURE 4, is a true ring shaped member. Mounted in the borein stator ring 26is the rotor '28 which is radially slotted to receive the vanes 30 which bear against the inner wall of stator ring 26. 7
Both rotor 28 and stator ring 26 have a running fit between plates 20 and 22 so that the stator ring can rotate with the rotor when the unit is operated.
. Rotor 28 has journal portions 31 extending therefrom in opposite directions that 'are'supponted on the needle bearings '32 in the heads IO-and 12 I The rotor is bored through and in about the center thereof has a splined portion 34 that engages the splined portion 36 of a drive shaft 38 that issupported on the antifriction bearings 40 in'the heads.
It will be apparent that the shaft is journalled independently of the rotor'thus allowing for some slight freedom of movement between the rotor and the shaft'and relieving the shaft'o-f transverse loads and permitting'somewhat more inexpensive machining and construction than if the shaft and rotor were integral.
The projecting end of shaft '38 issealed to the of the unit by the sealing means at 42. r v j The unitmay be-su'pported-by a mounting ring 44'bolts to head 10 andhaving a'footp'ortion 46.-
Fluid is supplied to the unit by way of the fittin'gs 48 and 50 mounted on head 12 and to which conduits-are connected that communicate through the fittings with-the arcuate tapering passages 52" and 54 respectivelyformed inside head12 and communicating via thearcuate slots 56 and 58 respectively with'the' slots-'60a., 60b and 62a, 62b in the wear plate 22. These last mer'ltion'ed-s'lots direct the fluid into'the spaces between the rotor and the stator'ring and betweenthe spaces between the values? The other wear plate 20' may be made substantially identical with wear plate 22 and have similar 'ports therein. "z
The wear plates also comprise an annular groove 64 which is'positioned so as to communicate with the enlarged regions 67 located at the' inner ends ofthe slots 69 in which'the vanes 36 stemmed; I;
The aforementioned groove 64 in at least 'wear' plate 22 'is adapted for communicating with passage means .66 extending laterally into head 12 from the sides thereof andterminating' in the short sections d s'which open to the back of -,wear plate 22in the region of the. annular groove. 64. V p f The drilled recesses 70in the back of wearplate 22 communicate-,at their one ends with the. annular groove 64 and at their other ends with the short passages 68 so body that communication withthe saidannular groove and thus with the enlarged spaces 61at the inner ends of the vanes can-belha'd eitherflthrough' one or both of the passages 66 in head 12.
- The stator rin'g 26is supported inside the center ring it member 14 onicircumfe'rentially spaced -land"areas""71" a 3 which define therebetween chambers that are utilized for balancing the thrust on the stator ring.
In FIGURE 4, for example, at the top and bottom of the stator ring are the chambers 72 and 74 which communicate with the slots adjacent thereto in the wear plates or side plates by the milled slots 76 and 78 respectively formed in the side plates.
It will be evident that in either direction of rotation of the rotor and with the device operating as either a pump or a motor, one of the chambers 72 and 74 will be under inlet pressure and the other will be under discharge pressure and that the one under pressure will always be associated with the side of the stator ring which is under internal pressure.
At the sides of the stator ring are the chambers 80 each of which communicate via milled slots 82 in the side plates with passages 84 formed in head 12 and which passages are interconnected and lead to a drain passage 86. The chambers 80 are thus continuously under drain pressure.
The described arrangement is utilized for fully balancing the hydraulic thrust on the stator ring due to the working pressure therein.
In one unit, for example, the stator bore is 3% in diameter and there is thus a projected area under pressure which measures 3%" transversely of the unit.
This is balanced oil? by making the adjacent one of the chambers 72, 74 so that it has a 3 projected dimension transversely of the pump and by making the land areas in the opposite sides thereof so that each has a dimension measured transversely of the unit.
The land areas at their ends adjacent the pressurized chamber will be under full pressure and at their other ends will be under drain pressure so that the effectiveness of each is reduced by half so that the total projected area on the outside of the stator ring that is underpressure will be exactly epual to the projected area inside the stator ring. The stator ring thus floats inside the center member 14 and will rotate with the stator on account of the frictional engagement of the vanes with the inside of the stator ring.
It will be understood that since the stator ring and rotor are not concentric, there will be some slight slippage between the ends of the vanes and the inside of the stator ring but this is greatly minimized over what occurs in units where the stator ring is not rotatable and there is thus substantially less Wear, less frictional loss and a great deal less chance the surface of the stator orthe ends of the vanes will become galled While the unit is operating.
Due to the reduced slippage between the vanes and the stator ring it is possible to use a higher pressure for urging the vanes outwardly without inducing the danger of accelerated wear and increased frictional loss.
A typical hydraulic circuit in which the unit according to the present invention is adapted for being used is illustrated in FIGURE 8. v
In this figure the unit according to the present invention is indicated at 90 and it is running as a unidirectional motor with there being a supply of fluid to the unit from a pump 92.
The pump discharges through a conduit 94 and throttle valve 96 to the inlet of a spring loaded check valve 98. The discharge side ofthe spring loaded check valve is connected with an open center reversing valve 100 having one service'po'rt connected by conduit 102 with one side of the unit 90 while the other side of the unit 90 is connected by conduit 104 through check valve 106 with the other service port or valve 100, the said check valve opening toward the service port.
Connected between conduits 104 and 102, is a relief valve 108 which is adapted for being piloted open by pressure conducted thereto via conduit 110 from conduit 104.
The aforementioned spring loaded check valve 98 maintains a predetermined pressure in conduit 94 on the inlet 4 side of the check valve and this pressure is conducted by a conduit 112 to the unit and is utilized for pressurizing the inner end of the vanes. By this arrangement, with pump 90 operating continuously, the vanes are always pressurized.
When valve is adjusted to run position, fluid will be delivered to conduit 102 and cause unit 90 to operate with fluid discharging therefrom through conduit 104 and check valve 106 to valve 100.
In the centered position of valve 100, and in which position it is illustrated in FIGURE 8, both the pump 92 and the vaned unit of the present invention 90 are connected to the tank and the unit 90 can thus coast freely. The vanes at this time remain pressurized so that the unit is ready to be placed in operation instantly.
In the other position of valve 100, in which the valve member is moved downwardly from its FIGURE 8 position, the unit 96 is braked and it will run as a pump with fluid being discharged from conduit 104 passing through relief valve 108 to conduit 102. This relief valve will control the pressure on the discharge side of unit 90 and cause a retarding or braking action which will slow down the unit more or less rapidly depending on the setting of relief valve 108.
The foregoing example is merely one of the many manners of using the unit of the present invention and it will be understood that the particular illustration where the unit runs as a unidirectional motor, is not intended in any way to limit the present invention.
It will'be understood that this invention is susceptible to modification in order to adapt it to different usages and conditions; and, accordingly, it is desired to comprehend such modifications within this invention as may fall within the scope of the appended claims.
1. In a vaned hydraulic unit; a slotted rotor, vanes in the slots of the rotor, an inner stator ring surrounding the rotor and eccentric therewith, an outer stator ring rotata'bly supporting said inner stator ring, said outer stator ring comprising axial recesses formed on the inner surface thereof at diametrically opposite positions on an axis at right angles to the axis of eccentricity of the rotor and inner stator ring, each said chamber being hydraulically connected with the inside of the inner stator ring immediately opposite thereto, said outer ring being formed with exhaust chambers formed therein at diametric points on the axis of eccentricityof the rotor and inner stator ring, land areas between said chambers forming the direct support of the inner stator ring in the outer ring, and the area of each of saidfirst'mentioned chambers plus one-half the areas of the said land areas being equal to the projected area of the inside of said inner stator ring that is under pressure, and end members engaging opposite sides of said outer stator ring and com prising bearing means for supporting said rotor and a drive shaft therefor.
2. In a hydraulic pump or motor; a frame, a slotted rotor rotatably journaled in the frame, a drive shaft rotatably journaled in the frame independently of the rotor extending through the rotor and splined thereto, vanes in the slots of the rotor, ported side plates in the frame on opposite sides of the rotor, a stator ring rotatably supported in the frame eccentric to the rotor and slidably fitted between the side plates, means for supplying fluid through the side plates to the spaces between the vanes, means for supplying fluid to the inner ends of the vane slots for urging the vanes outwardly into engagement with the inner surface-of the stator ring, and passages in the side plates connecting the outer surface of the stator ring at any point thereabout with the inside of the stator ring along the same radial line, said frame comprising a center ring partsurrounding and supporting said stator ring.
3. In a hydraulic pump or motor; a frame, a slotted rotor rotatably supported in the, frame, a drive shaft rotatably supported in the frame independently of the rotor extending through the rotor and splined thereto, vanes in the slots of the rotor, ported side plates in the frame on opposite sides of the rotor, a stator ring rotatably supported in the frame eccentric to the rotor and slidably fitted between the side plates, means for supplying fluid through the side plates to the spaces between the vanes, means for supplying fluid to the inner ends of the vane slots for urging the vanes outwardly into engagement with the inner surface of the stator ring, hydraulic bal- 10 ancing chambers in the frame around the stator ring, and passages in said side plates hydraulically connecting the chambers with the inside of the stator ring whereby the thrusts on the stator ring from pressures inside are balanced by equal and opposite thrusts on the outside of the stator ring so that the stator ring floats in the frame and will turn with the rotor. I 7
References Cited in the file of this patent UNITED STATES PATENTS 1,460,487 Hawkins July 3, 1923 2,918,877 Woodcock Dec. 29, 1959 2,924,182 Blasutta et al. Feb. 9, 1960 FOREIGN PATENTS 14,968 Great Britain 1915 835,271 France Sept. 19, 1938