US3451344A - Vane pump - Google Patents

Description

June 24, '1969 R. E TRICK 3,451,344

VANE PUMP Filed July 15, 1967 Sheet of 2 INVENTOR ROBERT E. TRICK y WM, I 9

.7 Attorneys.

R. E. TRICK VANE PUMP June 24, 1969 Sheeft A 4 8 T 3 INVENTOR: ROBERT EJTRICK Filed July 13, 1967 By W/M, W #45444.

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United States Patent 3,451,344 VANE PUMP Robert E. Trick, Racine, Wis., assignor to Webster Electric Company, Inc., Racine, Wis., a corporation of Delaware Filed July 13, 1967, Ser. No. 653,227 Int. Cl. F04c /04, 1/00; F04b 21/08 US. Cl. 103120 14 Claims ABSTRACT OF THE DISCLOSURE A pump housing has a chamber within which is a vane pump assembly including a rotor, vanes slidable in the rotor, a thrust ring and a pair of end plates. One end plate includes a series of outlet ports opening into the housing chamber and communicating with approximately 270 of the pumping region in order to produce counterbalancing forces on opposite regions of the rotor. An outlet port in the housing conducts high pressure fluid from the housing chamber. The end plate includes an inlet port communicating with about 90 of the pumping region and with an inlet passage in the housing. The thrust ring is shiftable between the end plates to vary pump displacement under the control of a control piston operated by outlet pressure admitted from the housing chamber to a control cylinder through a passage in the control piston.

The present invention relates to vane pumps, and has for an object the provision of an improved vane pump having a simplified construction and having improved operating characteristics.

Conventional vane pumps include a rotor carrying a plurality of movable vanes engageable with a thrust ring, together with a pair of end plates or bushings engaging the opposed sides of the rotor, vanes and thrust ring. Pumping chambers are defined by the rotor, the inner surface of the ring, the vanes, and the end plates, and these chambers increase in size during the first half of each revolution of the rotor, and then decrease in size during the second half of the revolution. The end plates or bushings are commonly loaded by pump outlet pressure against the sides of the rotor and thrust ring to provide a seal and prevent the leakage of high pressure fluid from the pumping chambers.

In known vane pumps a low pressure inlet passage communicates with the space between the rotor and the ring throughout the region wherein the pumping chambers increase in size, and a high pressure outlet passage communicates with the region wherein the pumping chambers decrease in size. As a result, half of the rotor is subjected to low pressure and the other half is subjected to high pressure, and this pressure difference creates an unbalance of force acting on the rotor and resulting in large bearing loads.

It is conventional'in vane pumps to provide a pressure area or areas behind one or both of the end plates or bushings opposite the pumping chambers of the pump. Typically, the pressure areas are surrounded by seals and are communicated with the pump outlet by a system of passageways in the pump housing. Often the high pressure areas are of complex configuration to achieve loading forces accurately counterbalancing the axial loads caused by pressure fluid within the pumping chambers. Such constructions require considerable machining and are quite complicated. In addition, the pressure loading forces must be great enough to prevent leakage or slip losses from the high pressure zones of the pump to the interior of the pump housing. Because of the necessity of the large pressure loading force, excessive friction is created "ice between the rotor and the side plates, and between the ring and the side plates. This friction increases the force required to rotate the rotor, as well as the force required to vary the displacement of the pump by shifting the thrust ring.

Because of such disadvantages, known vane pumps are limited to continuous operation at pressures of about 600 pounds per square inch, and to instantaneous ratings of about 1000 pounds per square inch. In accordance with the present invention, there is provided an improved and simplified vane pump wherein bearing loads and friction losses are greatly reduced, major slip or leakage paths are eliminated, and the operating characteristics of the pump are substantially improved. A pump constructed in accordance with the present invention can operate at much higher pressures than pumps used in the past.

In accordance with the present invention there is provided a vane pump having a housing with a chamber in which is disposed a pumping assembly including a vanecarrying rotor, a thrust ring engaged by the vanes, and a pair of end plates. In order to eliminate major leakage paths and thereby reduce the required pressure loading forces, substantially the entire pumping chamber is subjected to high pressure fluid. Only a small region of the housing chamber, adjacent the low pressure zone of the pump, is isolated by a seal and serves as part of the low pressure fluid inlet. The entire remainder of the housing chamber serves as part of the high pressure fluid outlet, and there is no necessity to prevent leakage from the high pressure zone of the pump into the interior of the housing chamber.

The pump friction losses are substantially reduced, because throughout the high pressure zone the end plates float as they are exposed to outlet pressure only. The only sealing force required is in the vicinity of the low pressure zone of the pump, and as appears below, this zone is of small extent.

In order to reduce bearing loads, and in accordance with a feature of the invention, the high pressure zone of the pump encompasses more than half of the region between the rotor and the thrust ring. Thus the rotor is subjected to high pressure in the first quadrant of rotation, and also in the third and fourth quadrants. The low pressure, or inlet zone, is restricted approximately to the second quadrant. Thus the forces applied to the rotor in the first and third quadrants balance one another, and the bearing load is reduced approximately in half.

Another advantage obtained with the construction of the present invention is simplicity of construction because of the elimination of complex seals and passages used heretofore to achieve pressure loading. In addition, the application of outlet pressure around the periphery of the thrust ring makes it possible to use a smaller ring. Furthermore, a simplified displacement control is conveniently obtained by introducing fluid directly from the pressurized housing chamber into a control cylinder by way of a passage in the body of a control piston.

Further objects and advantages of the invention will appear from the following description of an illustrative embodiment of the invention wherein reference is made to the accompanying drawings, in which:

FIG. 1 is a section view-of a vane pump embodying the features of the invention;

FIG. 2 is a sectional view taken along the line 2-2 of FIG. 1;

FIG. 3 is a sectional view taken along the line 3-3 of FIG. 1; and

FIG. 4 is a sectional View taken along the line 4-4 of FIG. 1.

Referring now to the drawing, there is illustrated a vane pump embodying the features of the present invention and designated as a whole as 10. The pump 10 is provided with a housing including a body 12, a spacer 14 and a cover 16, these being fastened together by means of bolts 18. A pumping assembly or cartridge, designated as a whole by the reference numeral 20, is disposed within an interior chamber or cavity 22 of the pump housing.

As shown in FIGS. 1 and 2, the pumping cartridge 20 includes an annular thrust ring 24 sandwiched between a pair of end plates 26 and 28. Within the cylindrical region enclosed by the ring 24 and end plates 26 and 28 is mounted a rotor 30 provided with the customary slots within which are mounted a plurality of vanes 32.

As will be readily understood by those skilled in the art, as the rotor 30 rotates the vanes 32 bear against the inner surface of the thrust ring 24 and reciprocate in the slots in the rotor. The thrust ring 24, the vanes 32, the rotor 30 and the end plates 26 and 28 define a series of pumping chambers, some of which are designated as 34 in FIG. 2. Assuming the rotor 30 to be rotating in the direction indicated by the arrow in FIG. 2, the pumping chambers 34 increase and then decrease in volume during each revolution. More specifically, the pumping chambers 34 assume their minimum volume at the nine oclock position as shown in FIG. 2. As the chambers rotate from this position through the first and second quadrants of rotation to the three oclock position, they increase in volume from the minimum to the maximum volume. Upon rotation through the third and fourth quadrants from the three oclock position to the nine oclock position, the chambers 34 decrease in size from the maximum volume to the minimum volume.

In accordance with an important feature of the present invention, and in order to reduce the radial forces acting on the rotor 30, the passages permitting fluid to flow to and from the pumping chambers 34 are arranged so that counterbalancing forces are produced on the rotor. More specifically, and as best shown in FIG. 3, the end plate 26 is provided with an inlet port 36 communicating with an inlet passage 38 in the body 12 (FIG. 4), and with a series of outlet ports 40 communicating with an outlet passage 42 in the body 12. As the pumping chambers 34 move past the inlet port 36 in the second quadrant of rotation, where they increase in size, they receive low pressure inlet fluid from the passageway 38. Then as the pumping chambers 34 move past the outlet ports 40 in the third, fourth and first quadrants, the fluid is expelled at a high pressure from the outlet ports 40. Since high pressure fluid is present within the chambers 34 in the first quadrant, the device acts as a motor in this quadrant and some portion of the pump displacement is sacrificed. However, since high pressure fluid acts on the rotor in both the first and third quadrants, the forces acting against the rotor in these quad-rants counterbalance one another, effectively cancelling each other out. As a result, the bearing load is reduced significantly as compared to conventional vane pumps wherein high pressure acts on half of the rotor and low pressure acts on the other half.

The rotor 30 is mounted on a rotatable driving shaft 44 by the means of a key 46, and the shaft is journalled in bearings 48 and 50 supported in the body 12 and cover 16 respectively. The bearings are lubricated by means of fluid leaking past a pair of bearing seals 52 and 54 carried in grooves in the body 12 and cover 16 respectively. Additional seals 56 and 58, also supported between the body 12 and cover 16, prevent the leakage of fluid from the chamber 22 to the exterior of the housing. Leakage fluid from the shaft bearings is returned to sump through a slip drain 60.

In accordance with an important feature of the present invention, the friction forces within the pump are reduced, and the problem of leakage of fluid from the high pressure areas of the pump are eliminated. This is accomplished by subjecting substantially the entire interior chamber 22. of the pump housing around the pumping cartridge to high pressure fluid. More specifically, the outlet ports 40 in the end plate 26 open into a relieved portion 22a of the chamber 22. Accordingly, high pressure fluid from the outlet ports 40 is in continuous and free communication with the entire outer surface of the thrust ring 24, with the areas of engagement between the thrust ring 24 and the end plates 26 and 28, and with a substantial portion of the peripheral areas of the outer surfaces of the end plates 26 and 28. High pressure fluid from the chamber 22 is discharged from the pump body through the outlet passage 42, which passage communicates continuously with the relieved portion 22a of the chamber 22.

Inlet fluid from the passage 38 enters a low pressure region bounded by a seal 62 disposed between the inner wall of the body 12 and the outer surface of the end plate 26. With the exception of the area within the seal 62 and the areas within the bearing seals 52 and 54, the entire chamber 22 outside of the pump assembly 20 is subjected continuously to pump outlet pressure and, in fact, serves as part of the pump outlet passageway. As a result, in the high pressure zone of the pump, extending throughout the first, third and fourth quadrants, the end plates are subjected to high pressure both on their inner and outer surfaces. Thus the end plates float-that is, they are not pressure loaded tightly against the rotor 30 or the thrust ring 24. Since the housing cavity serves as part of the discharge passage, it is not necessary to prevent high pressure fluid from escaping between the thrust ring and end plate and into the housing chamber.

In the low pressure region of the pump, the high fluid pressures existing in the chamber 22 urge the end plates 26 and 28 against the rotor and the ring to prevent leakage of high pressure fluid into the inlet zone. The friction forces produced in this limited area are small as compared to forces experienced in known pumps where end plates are pressure loaded in the usual manner.

Since the entire outer surface of the thrust ring 24 is subjected to high pressure, it has been found that it is not necessary to use a large and strong thrust ring, such as is required where the outer surface of the thrust ring is not subjected to high pressures.

The illustrated pump 10 is of the variable displacement type, and movement of the thrust ring 24 in a radial direction with respect to the rotor 30 varies the pump displacement. As illustrated in the drawings, the pump is in its full displacement position determined by an adjustable stop pin 64 carried in the spacer 14. In order to reduce the pump displacement, the ring is moved away from the stop pin 64 over the surface of a guide pin 66. It will be understood that if the thrust ring 24 is moved to a position wherein it is concentric with the rotor 30, the pump displacement decreases to zero.

The pump 10 is automatically pressure compensated by a control arrangement generally designated as 68 (FIG. 2). A control cylinder 70 formed in the spacer 14 is provided with a control piston 72 having a reduced diatrneter nose portion extending into the chamber 22 and engaging the thrust ring 24. The pump is normally biased to its illustrated maximum displacement position by means of a spring 78 held in compression between the piston 72 and a spring block 80 supported at the end of the cylinder against an adjustment bolt 81 carried by a cap plate 82. The interior of the cylinder 70 is subjected to pump outlet pressure by means of a passageway 84 conveniently formed in the body of the piston 72. This simplified arrangement for introducing high pressure fluid into the cylinder is made possible by the fact that the interior of the pump chamber is subjected to pump outlet pressure at all times. The piston, cylinder and spring are arranged so that when the pump outlet pressure reaches a predetermined selected maximum value, the forces created within the thrust ring overcome the piston force and move the thrust ring toward the minimum volume position thereby to maintain the selected maximum outlet pressure.

In order to bias the vanes 32 outwardly against the thrust ring 24, the end plate 26 includes passages 86 (FIG.

1) extending between the outlet ports 40 and an annular groove 88 communicating with the unders'ides of the vanes. A balancing groove 90 is provided in the end plate 28. High pressure fluid acts on the bases of the vanes 32 to urge them outwardly toward the thrust ring 24.

While the present invention has been described in connection with a particular embodiment of the invention, those skilled in the art may devise other embodiments and modifications falling within the spirit and scope of the invention. The present invention is not limited to details of the described embodiment except as set forth in the accompanying claims.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

1. A vane pump comprising a housing having a cavity therein, a pumping assembly disposed within said cavity and including a rotor, a plurality of vanes movably supported on said rotor, a thrust ring surrounding said rotor and engaged by said vanes, and a pair of end plates abutting the sides of said rotor and thrust ring and vanes, said end plates, rotor, thrust ring and vanes defining a series of pumping chambers, means for rotating said rotor to cause said chambers alternately to increase and decrease in size, a first fluid passage in said housing communicating with said pumping chambers throughout substantially less than half of their path of rotation, and a second fluid passage communicating with said pumping chambers throughout substantially more than half of their path of rotation to produce counterbalancing forces acting against opposite portions of said rotor.

2. The vane pump of claim 1, said first fluid passage comprising a low pressure inlet passage, and said second fluid passage comprising a high pressure outlet passage.

3. The vane pump of claim 2, said inlet passage communicating with said pumping chambers throughout substantially half of the region wherein said pumping chambers increase in size, and said outlet passage communicating with said pumping chambers throughout substantially the other half of the region wherein said pumping chambers increase in size and substantially all the region Wherein said chambers decrease in size.

4. A vane pump comprising a housing having a cavity therein, a vane pump assembly disposed within said cavity and including a rotor, a plurality of vanes movably supported on said rotor, a thrust ring surrounding said rotor and engaged by said vanes, and a pair of end plates abutting the sides of said rotor and thrust ring and vanes, said end plates, rotor, thrust ring and vanes defining a series of pumping chambers, means for rotating said rotor to cause said chambers alternately to increase and decrease in size, high pressure outlet port means in said vane pump assembly communicating with said pumping chambers in a high pressure region wherein the pumping chambers decrease in size, said outlet port means opening directly into said housing cavity, and an outlet passage in said housing communicating with said housing cavity for conducting high pressure fluid from said cavity, the inner walls of said housing cavity being spaced from said thrust ring and said end plates opposite said high pressure region to allow free communication of high pressure fluid to the inner and outer surface of said thrust ring and end plates adjacent the high pressure region.

'5. A vane pump comprising a housing having a chamber, a pump assembly in said chamber, said assembly including a thrust ring, a rotor mounted for rotation within the ring, a plurality of vanes movably mounted on said rotor and engaging said ring, a pair of end plates abutting said ring and said rotor, said rotor, ring and end plates defining a pumping area having high and low pressure zones, said housing being relieved away from said pumping assembly adjacent said ring and adjacent the peripheral portions of the end plates and adjacent the sides of said end plates opposite said high pressure zone, an outlet passageway in said housing communicating with the chamber, and outlet port means associated with said pumping assembly and communicating said chamber with the high pressure zone of said pumping area.

6. A vane pump as claimed in claim '5 further comprising an inlet passageway in said housing, an inlet port in one of said end plates communicating with the low pressure zone of said pumping area, and seal means between said housing and said one end plate surrounding the intersection of said inlet passageway and inlet port.

7. A vane pump as claimed in claim 6, said outlet port means establishing communication between said chamber and more than 180 of the circumference of said pumping area.

8 A vane pump said claimed in claim 7, said inlet port communicating with approximately of said pumping area, said outlet port means communicating with approximately 270 of said pumping area.

9. A vane pump comprising a housing having a chamber therein, a pumping assembly in said chamber, said pumping assembly including a thrust ring, a rotor rotatably mounted within said thrust ring, a plurality of movable vanes carried by said rotor and slidable on the inner surface of said thrust ring through a high pressure zone and a low pressure zone, a pair of end plates engageable in sealing relation with said rotor and said ring, a fluid inlet port in one of said end plates in communication with said low pressure zone, an inlet passageway in said housing intersecting said inlet port, sealing means between said one end plate and said housing, said sealing means surrounding the region of intersection of said inlet port and inlet passageway and defining a low pressure region of said housing chamber, a fluid outlet port in said pumping assembly in communication with said high pressure zone, the walls of said chamber outside said sealing means being spaced from said thrust ring and from the peripheral portions of said end plates and from the sides of said end plates opposite said high and low pressure zones, and said chamber communicating with said fluid outlet port and constituting a high pressure region.

10. The vane pump of claim 9 wherein said low pressure region of said housing chamber is confined to approximately one quadrant of the peripheral portion of said one end plate.

11. The vane pump of claim 10* wherein said high pressure zone comprises approximately three quadrants of the region between said rotor and said ring, the entire extent of said high pressure zone being in continuous communication with the high pressure region of said housing chamber.

12. The vane pump of claim 9, said thrust ring being movable in a radial direction with respect to said rotor for varying the displacement of said pump, a cylinder in said housing, a control piston slidable in said cylinder and extending into said high pressure region and engaging said thrust ring for controlling the position thereof, and a passageway through said piston for admitting fluid from said high pressure region to said cylinder.

13. A vane pump comprising:

a stator assembly including a thrust member having a circular inner surface, and including a pair of side walls cooperating with the thrust member to define a cylindrical recess;

a driving shaft extending into said recess parallel to and normally offset from the axis thereof;

bearing means associated with said stator assembly and supporting said shaft for rotation;

a rotor supported on said shaft for rotation in said recess, said rotor having a cylindrical periphery normally eccentric with respect to said inner surface of said thrust member;

a plurality of vanes supported on said rotor and slidably engaging said thrust member;

said rotor, vanes, side walls and thrust member defining a plurality of pumping chambers which increase and decrease in size during rotation of said rotor;

a low pressure fluid inlet passage communicating with References Cited said pumping chambers in the region where they in- UNITED STATES PATENTS crease in size; and a high pressure fluid outlet passage communicating 2,955,542 10/1960 a tlwith said pumping chambers in a region including 5 3,117,528 1/ 1964 Rosaen.

more than 180 ofb the periphery of said rotor an?1 3,137,235 6/1964 Brownproducing counter alancing forces acting on sai rotor and shaft thereby to reduce the bearing load. 6/1965 Pembone 103-136 14. The vane pump of claim 13, said rotor being rotat- 3,194,168 7/1965 Rosaen 103-136 able through first and second quadrants wherein said 10 pumping chambers increase in size and through third DONLEY STOCKING, Primary Exlfmillerand fourth quadrants wherein said pumping chambers decrease in size, said inlet passage communicating with GOODLIN Asmmm said pumping chambers substantially throughout said second quadrant, and said outlet passageway communicat- 15 ing with said pumping chambers substantially throughout 103 135 21 said first, third and fourth quadrants.

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