US3283724A - Double slipper fluid pump - Google Patents

Description

1955 H. c. LAZARUS DOUBLE SLIPPER FLUID PUMP 2 Sheets-Sheet 1 Filed June 9, 1965 Nov. 8, 1966 H. c. LAZARUS 3,283,724

DOUBLE SLIPPER FLUID PUMP Filed June 9, 1965 2 Sheets-Sheet 2 zz fip w Z I 3,283,724 Patented Nov. 8, 1966 3,283,724 DOUBLE SUPPER FLUID PUMP Herbert C. Lazarus, Plymouth, Mich, assignor to The Ford Motor Company, Dear-born, Mich, a corporation of Delaware Fiied June 9, 1965, Ser. No. 462,566 6 Claims. (Cl. 103-136) My invention relates generally to positive displacement fluid pumps. More particularly, it relates to improvements in a slipper type pump having 'a driving rotor situated rotatably within a pump housing which is ported suitably to accept fluid from a fluid reservoir and to deliver it under high pressure to a high pressure fluid delivery passage.

I am aware of conventional slipper type pump constructions having a rotor with pumping cavities formed in its periphery. The rotor is eocentrically mounted for rotation within a pump chamber in the pump housing. Slipper elements are situated loosely within the pump cavities on the periphery of the rotor. The radially cutward surfaces of the slippers sealing-1y engage the inner peripheral surface of the pump chamber.

Due to the eccentric position of the rotor with respect to the pump chamber, the structure of my invention defines a series of segmental pumping cavities that increase and decrease in size as the rotor is rotated through the pumping cycle. The housing can be ported suitabiy so that the pumping cavities, as they increase in size, are in fluid communication with a fluid inlet port. Dining the portion of the pumping cycle in which the pumping chambers decrease in size, the slippers establish a fluid seal that prevents communication between the pumping cavities and the inlet port. Communication is established at that time, however, with a high pressure delivery port.

In my improved pump construction, I have made provision for increasing the volumetric capacity of a slipper pump arrangement for any given rotor diameter. The improvements of my invention make it possible for the pump construction to achieve a pressure ratio that exceeds the pressure ratio that may be obtained with a conventional slipper pump construction of comparable size.

The provision of an improved pump construction of the type above set forth being a principal object of my invention, it is a further object of my invention to provide a slipper pump having slipper pumping elements that are arranged in pairs in peripherally disposed pumping cavities formed in the periphery of the pump rotor. When the slippers of my improved structure are arranged in this fashion, the volumetric capacity of each of the pumping cavities of the rotor progressively decreases as the individual cavities traverse the pumping arc. During this portion of the operating cycle the slippers tend to move toward each other. During the fluid intake portion of the operating cycle, however, the slippers tend to move tangentially away from each other.

It is another object of my invention to provide a positive displacement sliper pump of the type above set forth wherein spring means are disposed between the individual slippers of each pair thereby resisting the normal tendency of the slippers to move toward each other during operation as the slippers traverse the fluid intake are.

It is a further object of my invention to provide a positive displacement slipper pump of the type above set forth wherein the slipper elements establish an effective fluid seal on adjacent sealing surfaces in the pumping arcs formed in the rotor. Provision is made also in my improved pump structure for establishing sealing engagement of the outer peripheries of the slippers on the circular internal diameter of the pump chamber formed in the pump body.

Further objects and features of my invention will become apparent from the following description and from the accompanying drawings, wherein:

FIGURE 1 shows in schema-tic form a fluid flow circuit that includes my improved slipper pump construction;

FIGURE 2 shows in cross section an embodiment of my improved slipper pump construction; and

FIGURE 3 is an elevation view of the interior of the pump body shown in FIGURE -2.

In FIGURE 1, numeral 10 designates the pump body. It is formed with a cylindrical pump chamber 12 within which is rotatably j'our-naled a pump rotor 14.

The pump chamber 12 is closed by a closure plate, not shown. A fluid pressure delivery port 16 formed in the body 10 extends arena-te ly in fluid communication with the chamber 12. It communicates also with the fluid. discharge conduit 18.

An arcuate fluid inlet port 20 also is formed in the body It) in communication with the pumping chamber 12.

The rotor 14 is eccentrically positioned with respect to the geometric center of the cylindrical chamber 12. This creates a crescent shaped pumping cavity between the periphery of the rotor and the inner cylindrical surface of the chamber 12. The ports 16 and 20 extend arcuately with respect to the center of the chamber 12.

A fluid return flow passage 22 communicates with the inlet port 20. Also communicating with the inlet port 20 is a fluid supply passage 24 which extends to a fluid reservoir identified by reference character 26.

The rotor 14, as viewed in FIGURES 1 and 2, rotates in a counterclockwise direction. Fluid is discharged through port 16 to a hydraulic apparatus 28 which responds to hydrostatic pressure. A flow return passage 30 interconnects the apparatus 28 with the sump or reservoir 26.

A bypass passage 32 communicates with passage 18. Communicating with this passage 32 is a pressure relief valve 34 which is spring urged to a bypass passage closing position. When the pressure in passage 32 reaches a predetermined value, the relief valve 34 will open thereby permitting by pass flow to enter the return passage 22. This pas-sage 22 terminates in a nozzle which, by preference, directs fluid in the direction of motion of a point on the periphery of the rotor 14. The flow from the passage 24 is combined with the flow from the nozzle at the end of passage 22 in a manner described in U. S. Patent No. 2,983,226.

The rotor 14 is powered by any suitable power source. If the pump is used with automotive accessories, the rotor 14 would be driven by means of a suitable accessory torque delivery mechanism powered by the vehicle engme.

In FIGURE 2, I have illustrated more particularly the construction of the rotor and the slipper elements that are associated with it. The rotor is formed with a plurality of recesses 36 located on the periphery of the rotor in the embodiment shown. There are eight such recesses at evenly spaced intervals. Situated between each recess is a sealing element 38 having a sealing surface 49 which slidably engages the cylindrical surface of the opening 12 as an are between the trailing edge of the port 16 and the leading edge of the port 2% as seen in FIGURE 1.

Situated in each recess 36 is a pair of slipper pumping elements 42 and 44. Element 42 is formed with a sealing surface 46 and a corresponding sealing surface 48 is formed on element 44. The surfaces 46 and 48 engage respectively the juxtaposed sides of the recess 36.

A spring 50 is located between each pair of slipper pumping elements 42 and 44. Each spring urges its companion slipper pumping elements in tangential directions thereby tending to separate them. In this fashion sealing engagement is established between the surfaces 46 and 48 and the side surfaces of the recesses 36.

The radial thickness of the slipper elements 42 and 44. may be slightly less than the radial depth of the recesses 36. The outer surfaces 52 and 54 of the elements 42 and 44 are formed with a cylindrical shape which causes them to sealingly engage the cylindrical surface of the chamber 12.

As the rotor 14 rotates in the direction of the arrow shown in FIGURES 1 and 2, a slight wedging action is established by the slipper elements 44 between the inner cylindrical surface of the chamber 12 and the adjacent sealing surface of the recess 36. This improves the sealing action at both the surface 48 and the surface 54.

It will be apparent from an inspection of FIGURE 2 that the pumping chambers 36 are in fluid communication with the intake port 20 throughout a substantial arcuate extent. As each pair of slipper elements 42 and 44 traverse the arcuate extent of the intake port, the slipper elements 42 and 44 move radially outwardly thereby increasing the volume of the cavities in the recesses 36 that communicate with the intake port. This increase in volume causes fluid to pass from the intake port into the recesses 36.

The bottom-dead-center position is shown in FIGURE 1. At that time one slipper 42 of one recess 36 and the companion slipper element 44 of the next preceding pair of slipper elements establish a seal between the trai ing edge of the intake port 20 and the leading edge of the discharge pressure port 16. As the rotor continues to rotate and each cavity 36 passes the bottom-dead-center position, the volume of fluid in each recess 36 is brought into communication with the discharge port 16. As each recess 36 traverses the arcuate extent of the discharge port its volume decreases progressively. This causes the fluid to be discharged under pressure into the discharge port. Pumping action continues until the pair of slipper elements approaches the top-dead-center position of FIG- URE 2. When the individual pairs of slipper elements reach the top-dead-center position, they again are effective to establish a seal between the high pressure discharge port and the low pressure intake port. The seal, of course, can be supplemented also by the sealing effect of the surface 40 on the rotor portion 38.

When I employ a slipper arrangement of this type, a larger volume of fluid can be pumped for each revolution of the rotor of any given size than the corresponding volume of fluid that can be pumped with a conventional slipper pump of the type illustrated schematically, for example, in US. Patent No. 2,983,226. In addition to the foregoing, the use of separator springs between the individual pairs of pumping elements reduces the tendency of the slipper elements to vibrate during operation, This tends to avoid a noise problem that is commonly associated with slipper pumps of this type. as a damper which prevents a build-up in vibration forces.

The slipper elements themselves can be made of sintered iron if desired. Likewise the rotor can be made of sintered iron although it also can be made of conventional materials and machined by means of sirnpl machining techniques in forming the recesses 36.

In a conventional slipper pump of the type generally indicated in Patent No. 2,983,226, there is a limitation on the number of recesses that can be formed in the periphery of the rotor. This, of course, reduces the pumping capacity. This limitation is avoided in my improved pump construction since a larger portion of the peripheral region of the rotor can be utilized for displacing fluid.

Having thus described a preferred embodiment of my invention, what I claim and desire to secure by U.S. Letters Patent is:

1. A positive displacement pump comprising a pump body, a pumping chamber formed in said pump body, a rotor rotatably disposed in said chamber, the axis of rota- The springs act tion of said rotor being displaced from the geometric center of said chamber, a plurality of recesses formed in the periphery of said rotor, said recesses having tangentially spaced sides that diverge radially outwardly with respect to each other, a pair of pumping elements movably mounted in each recess whereby said pumping elements diverge as they move radially outward, said pumping elements sealingly engaging the peripheral wall of said pumping chamber and adjacent sides of each recess, a pressure port communicating with said chamber and with each recess throughout a substantial arcuate extent with respect to the geometric center of said chamber, and a fluid supply port communicating with said chamber and with said recesses at a location spaced arcuately from the location of said pressure port.

2. A positive displacement slipper pump comprising a pump body, a circular pump chamber formed in said pump body, a cylindrical rotor rotatably journaled in said pump chamber for rotation about an axis that is displaced from the geometric axis of said chamber, a plurality of recesses formed in the periphery of said rotor, said recesses having tangentially spaced sides that diverge radially outwardly with respect to each other, said rotor and said pumping chamber cooperating to define a space of crescent shape, a fluid intake port communicating with said space throughout a substantial arcuate extent with one extremity thereof in proximity to the location of maximum radial thickness of said crescent shape space, a fluid pressure port communicating with said crescent shape space at a location spaced arcuately with respect to said intake port, a pair of pumping slippers mounted in each recesses whereby said pumping slippers diverge as they move radially outward, the slippers having a radially outwardly curved surface sealingly engageable' with the peripheral surface of said chamber, one side of each slipper sealingly engaging the adjacent side of its associated recess, the radially outward surface of one slipper of one recess and the radially outward surface of another slipper of another recess establishing a seal between the adjacent ends of each port.

3. A positive displacement slipper pump comprising a pump body, a cylindrical pumping chamber formed in said pump body, a cylindrical rotor rotatably journaled in said pump chamber for rotation about an axis that is displaced with respect to the geometric center of said pumping chamber, a plurality of recesses formed in the periphery of said rotor, said recesses having tangentially spaced sides that diverge radially outwardly with respect to each other, a pair of slipper elements disposed in each recess whereby said slipper elements diverge as they move radially outward, a fluid intake port located at one arcuate position in said pump body with respect to the geometric center of said pumping chamber, a pressure port formed in said pump body in fluid communication with said chamber at a location arcuately spaced from said intake port, said recesses communicating with each port alternately as said rotor is rotated, said recesses receiving from said intake port a volume of fluid as it traverses the arcuate extent of said intake port, the volume of the fluid in said recess decreasing progressively as said recess traverses the arcuate extent of said pressure port, the radially inward region of each recess and its associated pair of slippers defining an individual fluid pumping chamber of variable volume, each slipper having a first sealing surface sealingly engaging one side of its associated recess and another sealing surface sealingly engaging the inner peripheral surface of said chamber whereby each of said pumping chambers is isolated from an adjacent pumping chamber.

4. A positive displacement pump comprising a pump body, a pumping chamber formed in said pump body, a cylindrical rotor rotatably disposed in said chamber, the axis of rotation of said rotor being displaced from the geometric center of said chamber, a plurality of segmental recesses formed in the periphery of said rotor, a pair of of each pair are urged tangentially away from each other.

5. A positive displacement slipper pump comprising a pump body, a pump chamber formed in said pump body, a cylindrical rotor rotatably journaled in said chamber for rotation about an axis that is displaced from the geometric axis of said chamber, a plurality of recesses formed in the periphery of said rotor, said rotor and said pumping chamber cooperating to define a space therebetween the crescent shape, a fluid intake port communicating with said crescent shape space throughout a substantial arcuate extent with one extremity of each port in proximity to a location of maximum radial thickness of said crescent shaped space, a fluid pressure port communicating with said crescent shape space at a location spaced arcuately with respect to said intake port, a pair of pumping slippers mounted in each recess, the slippers having a radially outward curved surface sealingly engageable with the curved surface of said chamber, one side of each slipper sealingly engaging the adjacent side of its associated recess, the radially outward surface of one slipper of one recess and the radially outward surface of another slipper of another recess establishing a seal between the adjacent ends of said ports, and spring means situated between the slippers of each pair whereby the slippers of each pair are urged tangentially away from each other.

6. A positive displacement slipper pump comprising a pump body, a cylindrical pumping chamber formed in said pump body, a cylindrical rotor rotatably journalled in said pump chamber for rotation about an axis that is displaced with respect to the geometric center of said pumping chamber, a plurality of recesses formed in the periphery of said rotor, a pair of slipper elements disposed in each recess, a fluid intake port located at one arcuate position in said pump body with respect to the geometric center of said pumping chamber, a pressure port formed in said pump body in fluid communication with said chamber at a location arcuate-1y spaced from said intake port, said recesses communicatng with each port alternately as said rotor is rotated, said recesses receiving from said intake port a volume of fluid as it traverses the arcuate extent of said intake port, the volume of the fluid in said recess decreasing progressively as said recess traverses the arcuate extent of said pressure port, the radially inward region of each recess and its associated pair of slippers defining an individual fluid pumping chamber of variable volume, each slipper having a first sealing surface sealingly engaging one side of its associated recess and another sealing surface sealingly engaging the inner peripheral surface of said chamber whereby each of said pumping chambers is isolated from an adjacent pumping chamber, and spring means situated between the slippers of each pair whereby the slippers of each pair are urged tangentially away from each other.

References Cited by the Examiner UNITED STATES PATENTS 2,974,603 3/1961 Fraser 103-135 2,977,888 4/1961 Livermore 103-136 3,079,864 3/1963 Drutchas et al. 103--135 MARK NEWMAN, Primary Examiner.

R. M. VARGO, Assistant Examiner.

Claims (1)

1. A POSITIVE DISPLACEMENT PUMP COMPRISING A PUMP BODY, A PUMPING CHAMBER FORMED IN SAID PUMP BODY, A ROTOR ROTATABLY DISPOSED IN SAID CHAMBER, THE AXIS OF ROTATION OF SAID ROTOR BEING DISPLACED FROM THE GEOMETRIC CENTER OF SAID CHAMBER, A PLURALITY OF RECESSES FORMED IN THE PERIPHERY OF SAID ROTOR, SAID RECESSES HAVING TANGENTIALLY SPACED SIDES THAT DIVERGE RADIALLY OUTWARDLY WITH RESPECT TO EACH OTHER, A PAIR OF PUMPING ELEMENTS MOVABLY MOUNTED IN EACH RECESS WHEREBY SAID PUMPING ELEMENTS DIVERGE AS THEY MOVE RADIALLY OUTWARD, SAID PUMPING ELEMENTS SEALINGLY ENGAGING THE PERIPHERAL WALL OF SAID PUMPING CHAMBER AND ADJACENT SIDES OF EACH RECESS, A PRESSURE PORT COMMUNICATING WITH SAID CHAMBER AND WITH EACH RECESS THROUGHOUT A SUBSTANTIAL ARCUATE EXTENT WITH RESPECT TO THE GEOMETRIC CENTER OF SAID CHAMBER, AND A FLUID SUPPLY PORT COMMUNICATING WITH SAID CHAMBER AND WITH SAID RECESSES AT A LOCATION SPACED ARCUATELY FROM THE LOCATION OF SAID PRESSURE PORT.

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