Vane Pump Assembly

Abstract

The vane pump assembly includes a housing with an inner wall that surrounds an open chamber. A rotor is rotatably disposed in the open chamber and has a circular shape when viewed in cross section. A first pair of vanes are received in the rotor and are operably connected with one another by a first bell crank which is pivotable about a pivot axis such that movement of one vane inwardly into the rotor causes the other vane to move outwardly out of the rotor to maintain both vanes in contact with the inner wall as the rotor rotates relative to the housing during operation of the vane pump assembly.

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit and priority to U.S. Provisional Patent Application No. 62/311,003 filed Mar. 21, 2016, the entire disclosure being considered part of the disclosure of this application and hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is related, generally, to pneumatic and hydraulic pumps, motors and heat regenerative systems.

2. Related Art

In general, rotary vane pump assemblies are positive displacement pumps that include one or more vanes that are mounted to a rotor which is rotatable within a housing having an inner wall defining an open chamber. A pressure differential is applied across the vane, which causes the rotor to rotate within the open chamber of the housing. The rotor is coupled with an output shaft which may be attached to any suitable machine including, for example, an electric generator. During operation of such vane pump assemblies, it is important to maintain a fluid-tight seal between the vane and the inner wall of the housing in order to optimize efficiency and maximize power output.

One approach to maintaining the fluid-tight seal between the vane and the housing is to use springs to bias the vane against the inner wall of the housing. Rotary vane pumps that use this approach generally include two or more vanes, and a spring is disposed between the rotor and each vane to bias the respective vane in a radially outward direction and against this housing. The biasing forces exerted by the springs maintain the vanes in continuous contact with the housing through a full 360 degrees of rotation of the rotor within the open chamber of the housing.

Another approach to maintaining the fluid-tight seal between the vane and the housing is to provide open chamber with a non-circular shaped cross-section. The rotor is centered within the non-circular open chamber, and a vane extends through the rotor to engage at either end with an inner wall of the open chamber. The noncircularly shaped cross-section of the open chamber guides the vane through a reciprocating motion back and forth across the rotor to maintain both ends of the vane in contact with the inner wall to establish the fluid tight seals.

In some rotary vane pumps it is additionally important for the rotor to seal against the inner wall. In general this is accomplished by manufacturing the rotor and housing under tight tolerances in order to achieve a tight fit between the rotor and the inner wall of the housing. However, it is often costly as expensive and time consuming manufacturing and/or machining processes must be employed to achieve such tight tolerances.

SUMMARY OF THE INVENTION AND ADVANTAGES

One aspect of the present invention is related to a vane pump assembly which includes a housing with an inner wall that surrounds an open chamber. A rotor is rotatably disposed in the open chamber and has a circular shape when viewed in cross section. A first pair of vanes are received in the rotor and are operably connected with one another by a first bell crank which is pivotable about a pivot axis such that movement of one vane inwardly into the rotor causes the other vane to move outwardly out of the rotor to maintain both vanes in contact with the inner wall as the rotor rotates relative to the housing during operation of the vane pump assembly. The vane pump assembly constructed according to this aspect of the present invention allows for improved efficiency and cost effectiveness as compared to other known vane pump assemblies.

According to another aspect of the present invention, the bell crank includes a pair of resiliently deflectable arms which are made of a resiliently deflectable material such that the arms elastically deflect while the vanes move into and out of the rotor during operation of the vane pump assembly.

According to yet another aspect of the present invention, the bell crank is made as a single piece.

According to still another aspect of the present invention, each of the arms of the bell crank has an end with a socket, and each of the vanes has a ball-shaped end portion that is received in one of the sockets.

According to a further aspect of the present invention, the vane pump assembly further includes a second pair of vanes that are received in the rotor and are operably connected with one another by a second bell crank.

According to yet a further aspect of the present invention, the vanes are uniformly spaced from one another around the rotor.

According to still a further aspect of the present invention, the rotor has a pair of slots on opposite sides of each of the vanes, and sealing elements are disposed in the slots for sealing the vanes with the rotor.

According to another aspect of the present invention, a bearing block and a bearing pin are received in each of the slots with the bearing pins being rotatable relative to the bearing blocks such that the bearing pins roll in response to movement of the associated one of the vanes into and out of the rotor.

According to yet another aspect of the present invention, a leaf spring is disposed in one of the slots associated with each of the vanes. The leaf spring biases one of the bearing pins against the associated one of the vanes.

According to still another aspect of the present invention, pins operably connect the vanes of the first pair of vanes with the first bell crank.

According to a further aspect of the present invention, an end plate body is secured with the housing.

According to yet a further aspect of the present invention, a stabilizer plate contacts and seals against an end face of the rotor.

According to still another aspect of the present invention, a biasing mechanism biases the stabilizer plate against the end face of the rotor.

According to another aspect of the present invention, the biasing mechanism includes a plurality of set screws which are moveable into and out of the end plate body.

According to yet another aspect of the present invention, the biasing mechanism further includes a plurality of springs between the set screws and the stabilizer plate.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features and advantages of the present invention will be readily appreciated, as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

FIG. 1 is a cross-sectional view of a first exemplary embodiment of a vane pump assembly constructed according to one aspect of the present invention;

FIG. 2 is a perspective view of a rotor of the vane pump of FIG. 1;

FIG. 3 is a perspective view of the components that are inserted into the rotor of FIG. 2;

FIG. 4 is a sectional and fragmentary view of the vane pump assembly of FIG. 1;

FIG. 5 is another sectional and fragmentary view of the vane pump assembly of FIG. 2;

FIG. 6 is a sectional view of a second exemplary embodiment of the vane pump assembly; and

FIG. 7 is a sectional view of a third exemplary embodiment of the vane pump assembly.

DETAILED DESCRIPTION OF THE ENABLING EMBODIMENTS

Referring to the Figures, wherein like numerals indicate corresponding parts throughout the several views, a first exemplary embodiment of an improved vane pump assembly 20 is generally shown in FIGS. 1-4. The vane pump assembly 20 includes a housing 22 with an inner wall 24 which defines an open chamber that is generally elliptical, or oval, in shape when viewed in cross-section. The exemplary housing 22 has a total of four ports 26, 28 with two of them being fluid inlet ports 26 for conveying a fluid, such as steam, into the open chamber and two of them being fluid outlet ports 28 for dispensing the fluid out of the open chamber. Although two of each are shown in the exemplary embodiment, it should be appreciated that the housing 22 could be configured with any suitable number of inlet and outlet ports 26, 28.

The vane pump assembly 20 further includes a rotor 30 which is generally circular in shape and is centered within the elliptical open chamber of the housing 22. The rotor 30 is rotatable within the open chamber about an axis A, which is centrally located within the elliptical open chamber and the circular rotor 30. The rotor 30 is coupled with an axially extending input/output shaft 32 which may be fixed with the rotor 30 through any suitable means such that rotation of the rotor 30 relative to the housing 22 drives rotation of the shaft 32 and vice versa. The shaft 32 may be attached to any suitable power receiving device (not shown) for operating the vane pump assembly 20 to generate power. Alternately, the shaft 32 may be attached to a power source for operating the vane pump assembly 20 as a fluid compressor.

The exemplary embodiment of the rotor 30 has a total of four radially extending passages which are generally evenly spaced from one around the rotor 30. A vane 34 is received in each of the passages and is movable radially into and out of the respective passage for sealing against the inner wall 24 of the housing 22 to establish a total of four evenly distributed, circumferentially spaced and fluid-tight seals between the rotor 30 and the housing 22.

Each of the vanes 34 has an end with a first U-shaped opening which opens in a radially outward direction (away from the axis A) and within which a primary roller 36 is positioned. The primary rollers 36 have outer diameters which are similar to the widths of the first U-shaped openings. During operation of the vane pump assembly 20, rotation of the rotor 30 relative to the housing 22 generates a circumferential force which biases the vanes 34 and the primary rollers 36 in a radially outward direction to maintain the primary rollers 36 in contact with the inner wall 24 of the housing 22. The eccentric shape of the inner wall 24 drives the radial movement of the vanes 34 into and out of the passages of the rotor 30. Because the primary rollers 36 roll rather than slide along the inner wall 24 of the housing 22, friction losses during operation of the vane pump assembly 20 are minimized.

The housing 22 presents a pair of axially extending openings 38 which are diametrically opposed with one another and are located circumferentially between the inlet ports 26 and the outlet ports 28. The axially extending openings 38 are separated from the inner passage by thin and flexible portions 40 of the inner wall 24. A bar 42 is positioned in one or both of the openings 38, and the bar 42 is in contact with a plurality of set screws 44 which are accessible from outside of the housing 22. The radial position of the bar 42 is adjustable by threading the set screws 44 into and out of the housing 22 to manually increase or decrease a biasing force of the thin portion 40 of the inner wall 24 against the rotor 30. This allows for easy adjustment to optimize the seal between the inner wall 24 of the housing 22 and the rotor 30 and the friction between the rotor 30 and the inner wall 24 of the housing 22.

The vane pump assembly 20 further includes a pair of pressure balanced end plate assemblies which are joined with opposite axial ends of the housing 22 to seal the housing 22 against axial end faces of the rotor 30. Each of the end plate assemblies includes an end plate body 46 with an axially extending shaft opening that has a shaft bearing 48 disposed therein for receiving the input/output shaft 32. A shaft seal 50 is also disposed in the shaft opening for establishing a fluid tight seal between the end plate body 46 and the shaft 32. The end plate assemblies also include a plurality of circumferentially spaced bolts for fixing the end plate body 46 with the axial end faces of the housing 22. Each end plate assembly further includes a rigid stabilizer plate 52 with an annular shape which extends around the shaft opening. The stabilizer plate 52 is disposed in a groove of the end plate body 46 and has a thin and flexible membrane which faces away from the end plate body 46 for sealing against an axial end face of the rotor 30.

Each end plate assembly additionally includes an adjustable biasing mechanism for applying a biasing force against the stabilizer plate 52 to bias the membrane against the axial end face of the rotor 30 and establish a fluid-tight seal therebetween. The biasing mechanism includes a plurality of circumferentially spaced set screws 54 which are threadedly disposed in holes within the end plate body 46 and are movable in the axial direction by threading the set screws 54 into or out of the holes. A compression spring 56 is positioned between each set screw 54 and the stabilizer plate 52 for applying a biasing force against the stabilizer plate 52. The magnitude of the biasing force is adjustable by threading and unthreading the set screws 54 into and out of the holes. The adjustability of the biasing force allows for the optimization of the fluid tight seal and friction between the stabilizing plate 52 and the rotor 30.

During operation of the vane pump assembly 20 as a motor, a high pressure fluid enters the inner chamber through the inlet ports 26. Pressure differentials within the inner chamber of the housing 22 and across the vanes 34 has the effect of rotating the rotor 30 and driving rotation of the shaft 32. During operation of the vane pump assembly 20 as a fluid pump, the shaft 32 is driven by an external source to rotate the rotor 30 relative to the housing 22. The movement of the vanes 34 creates a pressure differential such that the pressure which leaves the inner chamber through the outlet ports 28 has a greater pressure than the fluid which enters the inner chamber through the inlet ports 26.

Pairs of the vanes 34 are operably connected with one another by a bell crank 58 which is pivotable about a fulcrum pin 60 that is attached with the rotor 30. Each of the bell cranks 58 is made as a single piece and is generally V-shaped with a pair of arms 62 that extend away from the fulcrum pin 60 to engage the pair of vanes 34. The arms 62 are angled relative to one another by approximately ninety degrees (90°). During operation, as one of the vanes 34 is pushed inwardly into the rotor 30 due to the eccentric shape of the inner wall 24, the bell crank 58 pivots about the fulcrum pin 60 to urge the other vane 34 radially outwardly to maintain contact with the inner wall 24. The bell cranks 58 are made of a resiliently deflectable material, such as an aluminum alloy or spring steel, such that the arms 62 deflect resiliently while the vanes 34 move in and out of the rotor 30 during operation of the vane pump assembly 20. The bell cranks 58 function to connect and influence the movement of the vanes 34 by harnessing a radially inward force from one vane 34 and transforming that force into a radially outward force on the other vane 34. In this embodiment, the ends of the arms 62 are connected with the ends of the vanes 34 via cylindrically-shaped pins to establish a pivoting relationship between each vane 34 and the associated arm 62.

The rotor 30 also presents a pair of axially extending slots on opposite sides of each vane 34 and which support a pair of bearing assemblies. Each of the slots contains a bearing block 64 with a semi-circular cutout and a cylindrically shaped bearing pin 66 that is rolls within the bearing block 64. The bearing pins 66 are in contact with the opposite sides of the respective vane 34 to provide a low friction interface to allow the vane 34 to move in and out of the rotor 30 during operation of the vane pump assembly 20.

One of the slots associated with each of the vanes 34 is wider than the associated bearing block 64 and bearing pin 66 such that there is a gap between the bearing block 64 and an inner surface of the rotor 30. A spring 68, such as a leaf spring, is inserted into this slot to bias the associated bearing block 64 and bearing pin 66 against the associated vane 34 thereby affirming a firm contact seal between the rotor 30 and both sides of the vane 34.

As shown, in the first exemplary embodiment, no mechanical fasteners are required to connect the vanes 34, primary rollers 36, bell cranks 58, etc. with the rotor 30. As such, the rotor assembly can be extremely quickly and efficiently assembled and inserted as a completed unit into the housing 22 during manufacture of the vane pump assembly 20. Also, most of these components can be made through extrusion, thereby allowing the rotor and the rotor components to be very cost effectively produced.

Referring now to FIG. 5, an alternate embodiment of the vane pump assembly 120 is generally shown with like numerals, separated by a prefix of “1” indicating corresponding parts with the above described embodiments. In this embodiment, each of the arms 162 extends away from the fulcrum pin 160 to an end with a socket, and the vanes 134 have ball-shaped ends that are received in the sockets at the ends of the arms 162. These ball and socket attachments allows the vane 134 to articulate relative to the arms 162 of the bell cranks 158 during operation of the vane pump assembly 120.

Referring now to FIG. 6, yet another alternate embodiment of the vane pump assembly 220 is generally shown with like numerals, separated by a prefix of “2” indicating corresponding parts with the above-described embodiments. In this embodiment, four total vanes 234 are disposed in the rotor 230, and each of the vanes 234 includes a second U-shaped opening 270 which opens in a radially inward direction (towards the axis A) and within which a guide roller 272 is located. The guide rollers 272 are fixed with the rotor 230 for guiding the radial movements of the vanes 234 into and out of the rotor 230 during operation of the vane pump assembly 220. Also, in this embodiment, the vanes 234 and the walls of the rotor 230 present a pair of aligned channels which receive sealing pins 274 that within the channels as the vanes 234 move into and out of the rotor 230. The sealing pins 274 also perform a sealing function to seal the sides of the vanes 234 with the rotor 230.

Referring now to FIG. 7, still another exemplary embodiment of the vane pump assembly 320 is generally shown with like numerals, separated by a prefix of “3” indicating corresponding parts with the above-described embodiments. In this embodiment, only a single vane 324 is provided, and that vane 324 extends diametrically across the rotor 330 and has a central opening through which the input/output shaft 332 extends. Also, a wedge 376 is disposed in one of the sets of aligned channels between the rotor 330 and the associated sealing pin 374. The wedge 376 is slidable within the associated respective channel for biasing the sealing pin 374 against the vane 334 and maintaining the fluid tight seals between the sealing pin 374 and the vane 334 and rotor 330.

Obviously, many modifications and variations of the present invention are possible in light of the above teachings and may be practiced otherwise than as specifically described while within the scope of the appended claims.

Claims

1. A vane pump assembly, comprising:

a housing having an inner wall which surrounds an open chamber;

a rotor rotatably disposed in said open chamber of said housing, said rotor being circular in shape when viewed in cross-section; and

a first pair of vanes received in said rotor and being operably connected with one another by a first bell crank which is pivotable about a pivot axis such that movement of one vane inwardly into said rotor causes the other vane to move outwardly out of said rotor to maintain both vanes in contact with said inner wall as said rotor rotates relative to said housing during operation of said vane pump assembly.

2. The vane pump assembly as set forth in claim 1 wherein said bell crank includes a pair of resiliently deflectable arms which are made of a resiliently deflectable material such that said arms elastically deflect while said vanes move into and out of said rotor during operation of said vane pump assembly.

3. The vane pump assembly as set forth in claim 1 wherein said bell crank is made as a single piece.

4. The vane pump assembly as set forth in claim 1 wherein each of said arms has an end with a socket and wherein each of said vanes has a ball shaped end portion that is received in one of said sockets.

5. The vane pump assembly as set forth in claim 1 further including a second pair of vanes received in said rotor and wherein said second pair of vanes are operably connected with one another by a second bell crank.

6. The vane pump assembly as set forth in claim 5 wherein said vanes are uniformly spaced from one another around said rotor.

7. The vane pump assembly as set forth in claim 1 wherein said rotor presents a pair of slots on opposite sides of each of said vanes and wherein sealing elements are disposed in said slots for sealing said vanes with said rotor.

8. The vane pump assembly as set forth in claim 7 wherein a bearing block and a bearing pin are received in each of said slots with said bearing pins being rotatable relative to said bearing blocks such that said bearing pins roll in response to movement of the associated one of said vanes into and out of said rotor.

9. The vane pump assembly as set forth in claim 8 further including a leaf spring disposed in one of said slots associated with each of said vanes and biasing one of said bearing pins against the associated one of said vanes.

10. The vane pump assembly as set forth in claim 1 wherein pins operably connect said vanes of said first pair of vanes with said first bell crank.

11. The vane pump assembly as set forth in claim 1 further including an end plate body which is secured with said housing.

12. The vane pump assembly as set forth in claim 11 further including a stabilizer plate which contacts and seals against an end face of said rotor.

13. The vane pump assembly as set forth in claim 12 further including a biasing mechanism for biasing said stabilizer plate against said end face of said rotor.

14. The vane pump assembly as set forth in claim 13 wherein said biasing mechanism includes a plurality of set screws which are moveable into and out of said end plate body.

15. The vane pump assembly as set forth in claim 14 wherein said biasing mechanism includes a plurality of springs between said set screws and said stabilizer plate.