US3729277A

US3729277A - Adjustable rotary vane tangency compressor

Info

Publication number: US3729277A
Authority: US
Inventors: C Allen
Original assignee: TRW Inc
Current assignee: Northrop Grumman Space and Mission Systems Corp
Priority date: 1970-07-15
Filing date: 1970-07-15
Publication date: 1973-04-24
Anticipated expiration: 1990-04-24
Also published as: CA943111A; JPS52252B1; GB1338772A; DE2129881A1; FR2101655A5

Abstract

A compressor having a closed-ended cylindrical compression chamber with an eccentrically positioned vane carrying rotor received therein and supported by end plates closing the cylinder, wherein the said end plates are pivotably attached to the cylinder by means of pivot pins allowing adjustment of the radial positioning of the rotor within the cylinder to establish zero clearance at the point of tangency after assembly and prior to final tightening, while maintaining the actual contact between the rotor and cylinder at the desired line of tangency and a locking means whereby the initial positioning of the rotor relative to the cylinder is assured against change during the operating life of the compressor.

Description

United States Patent 1191 Allen 11 3,729,277 1 51 Apr. 24, 1973 ADJUSTABLE ROTARY VANE TANGENCY COMPRESSOR [75] Inventor: Clifford H. Allen, Chesterland,

Ohio [73] Assignee: TRWInc.,C1eveland,Ohio

[22] Filed: July 15, 1970 21 Appl. No.: 55,010

[52] U.S.Cl ..4l8/l07,418/127 [51] Int. Cl ..F0lc 19/00, F03e 3/00, F04c 14/00 [58] Field of Search ..4l8/l07, 108, 109,

[ 56] References Cited UNITED STATES PATENTS 2,552,860 5/1951 Oliver ..4l8/2) 2,142,275 1/1939 Lane .418/30 X 3,385,513 5/19611 Kilgore.. ..4l8/82 2,493,525 1/1950 Bush t- ..418/3() x 3,185,241 5/1965 Jackson ..4l1-1/3l1 X FOREIGN PATENTS OR APPLICATIONS 1,183,989 2/1959 France ..4l8/3O Primary Examiner-Carlton R. Croyle Assistant ExaminerR. E. Gluck Attorney-Hill, Sherman, Meroni, Gross & Simpson [5 7 ABSTRACT A compressor having a closed-ended cylindrical compression chamber with an eccentrically positioned vane carrying rotor received therein and supported by end plates closing the cylinder, wherein the said end plates are pivotably attached to the cylinder by means of pivot pins allowing adjustment of the radial positioning of the rotor within the cylinder to establish zero clearance at the point of tangency after assembly and prior to final tightening, while maintaining the ac tual contact between the rotor and cylinder at the desired line of tangency and a locking means whereby the initial positioning of the rotor relative to the cylinder is assured against change during the operating life 01 the compressor.

4 Claims, 5 Drawing Figures Patented AM 24, 1973 3,729,277

3 Sheets-Sheet 1 IE I 7 55 INVEN TOR.

CZz' 4997/1612 Patented April 24, 1973 3 Sheets-Sheet 2 INVENTOR.

Patented April 24, 1973 3,729,277

3 Sheets-Sheet 5 BACKGROUND OF THE INVENTION 1. Field ofthe Invention This invention relates to rotary vane compressors and more particularly to a pivotable attachment between the compressor cylinder end plates and the compressor cylinder.

2. Prior Art Rotary vane compressors of the type to which this invention pertains are known to the art (see for example U. S. Pat. No. 3,385,513 to Kilgore).

Such compressors normally include a rotatable rotor member carrying radially movable vanes in grooves therein which is positioned interior of a cylindrical member. The cylindrical member is closed at either end by end caps. The rotor is eccentrically positioned within the cylinder and retained in place by the end caps which may include anti-friction bearing assemblies for supporting the rotor axis.

In order for such compressors to act efficiently, the eccentricity of the rotor must be such that its outer diameter is tangent to the inner diameter of the cylindrical member along a line extending from one end plate to the other. This line of tangency divides the high pressure area from the low pressure area of the compressor chamber and the pressure drop across the line of tangency may be quite great. It is therefore desirable to assemble the compressor with a zero clearance between the rotor and the cylinder wall at the line of tangency or with a clearance which will approach zero as the compressor approaches operating temperatures.

In order to obtain the proper operating clearance, it is necessary that the rotor be assembled into the cylindrical member with a critical tolerance fit. Due to the fact that the rotor is supported by the end caps and that the cylindrical member is held in place therebetween, it is difficult to obtain an exact fit in mass-manufactured compressors. This is due to the difficulty of obtaining continuous low-tolerance assembly on an assembly line as well as the extreme difficulty of low-tolerance manufacture of the components in a mass manufacturing setup.

In all such compressors and more specifically in compressors which are equipped with tangency seals, it is important that the actual line of tangency and the desired line of tangency be coincidental in order to achieve the desired operating performance and geometric relationships. In the case of a tangency seal, these are found to perform most efficiently when they are pressure loaded; that is, the radial load applied by the seal against the rotor surface is a function of the pressure differential across the low pressure side of the seal and the total area exposed to this pressure differential. Since the line of tangency determines the location of the division between the high pressure and low pressure areas of the seal, it is apparent that control must be exercised over the location of the actual contact line between the rotor and cylinder.

It has been found that during the normal operation of rotary vane compressors, thermal expansion loads as well as pressure and shock loads are encountered which cause the initial set" tangency clearance to be altered in spite of efforts to exert maximum tightening torque on the belts during assembly. It is therefore desirable to provide a locking means which provides sufficient resistance to slippage to prevent the alteration of the tangency clearance during operation of the compressor.

SUMMARY OF THE INVENTION This invention is directed to the solution of the above problem by providing a hinged connection between the cylindrical member and the rotor supporting end caps which will allow the members to be assembled together in a loose fit relationship and then pivoted with respect to one another around a pivot point which will assure contact of the rotor at the desired point of tangency. Thus, the rotor may be pivoted to the point of tangency after preliminary assembly of the system, and be maintained there at a desired force while the assembly is tightened. A lock member is provided to insure against misalignment after tightening of the assembly. In this manner, normal manufacturing variances in component sizes are accommodated by providing for setting of the tangency contact by a method which does not rely specifically upon low-tolerance fits between the components.

It is therefore an object of this invention to provide an improved rotary vane compressor.

It is a further and specific object of this invention to provide an improved rotary vane compressor wherein the actual line of tangency is at the desired geometric location while permitting adjustment of the tangency clearance.

It is a further and more specific object of this invention to provide a locking means whereby the set tangency clearance is maintained in spite of thermal expansion, pressure and shock loads encountered during operation of the compressor.

It is a further and more specific object of this invention to provide an improved rotary vane compressor wherein tangency clearance between the rotor and compressor chamber wall is adjustable.

It is yet another and more specific object of this invention to provide a rotary vane tangency compressor having a rotor supported in a cylinder by end caps which are pivotably connected to the cylinder to allow assembly line adjustment of the clearance between the rotor and cylinder wall.

BRIEF DESCRIPTION OF THE DRAWINGS I Other objects, features and advantages of the invention will be readily apparent from the following description of certain preferred embodiments thereof, taken in conjunction with the accompanying drawings, although variations and modifications may be effected without departing from the spirit and scope of the novel concepts of the disclosure, and in which:

FIG. 1 is a cross sectional view of the compressor of this invention;

FIG. 2 is a transverse cross sectional view of the compressor illustrated in FIG. 1 taken along the lines II-II of FIG. 1;

FIG. 3 is a fragmentary longitudinal cross sectional view of the compressor of FIGS. 1 and 2 taken along the lines III-III of FIG. 2;

FIG. 4 (on Sheet 1) is a perspective view of the locking member utilized to maintain alignment between the end plates and compressorcylinder; and

FIG. 5 is a cross sectional view of the compressor of FIG. 1 taken along the lines V-V of FIG. 1 illustrating the end cap and inlet.

The compressor as best illustrated in FIG. 1 includes a cup-shaped housing 11 which is partially closed at the open end 12 thereof by an end cap 13 secured thereto by projecting bolt lugs 14 and nuts 15. An internal end cap 16 is disposed within the housing 11 spaced from the bottom thereof, and is attached to the end cap 13 by means of a plurality of circumferentially spaced bolts 17. Entrapped between the end cap 13 and the end cap 16 is an internally cylindrical compression chamber member 18.

A central cup-shaped depression 19 in the end cap 16 receives an anti-friction bearing assembly 20 which in turn supports one end 21 of a shaft 22. An anti-friction assembly 23 disposed in a central bore 24 in the end cap 13 provides support for the shaft 22 on the other side of the compression chamber member 18. The end 26 of the shaft'projects out of the end cap 13 through a collar 27 which combines with a seal member 28 to close the bore 24 of the end cap 13. The axis of the shaft 21, as supported by the

end caps

13 and 16 is, in the final assembly, offset from the axis of the internally cylindrical compression chamber member 18. The shaft 21 supports a rotor 30 within the compression member 18. The rotor 30 extends from the end cap 13 to the end cap 16 and when the shaft 21 is rotated, the rotor will sealingly engage the side walls of the end caps and rotate therebetween.

As best shown in FIGS. 1 and 2, the rotor 30 has a plurality of circumferentially spaced slots 31 extending thereinto from the circumference 32 thereof and ter minating at a point 33 spaced from the shaft 21.

The slots 31, illustrated as being four in number, are equally disposed around the circumference of the rotor. A pair of bores 35 extend from the bottom 33 of the slots 31 and communicate with bores 36 through the shaft 21. The bores 36 communicate the bores 35 of opposed slots 31. Vanes 37 are received in the slots 31 and receive shoes 38 on their outer ends. Blind bores 39 in the bottoms 40 of the vanes 37 are aligned with the bores 35. Pins 42 are received in the blind bores 39 and extend through the

bores

35 and 36 into the blind bores 39 of the opposed vane. In this manner, opposed vanes operate as a set. Coil springs 43 are disposed around the pins 42 and bottom against the bottoms 40 of the vanes 37. Portions of the rotor 30 in the area of the slots 31 adjacent the bores 35 are hollowed out as at 35b to accommodate the coil spring 43 when the vane 37 moves outwardly from the slots. The action of the coil springs, entrapped around the pins 42, causes opposed vanes to operate as a unit so that when one of the opposed vanes is forced into its respcc- I tive slot, the other vane is urged outwardly from its slot.

As is illustrated in FIG. 1, in order to prevent the bores 36 from intersecting one another, the bores pertaining to one set of opposed vanes are spaced from the bores pertaining to the other set of opposed vanes in the 4-vane embodiment illustrated.

As best shown in FIG. 2, the rotor 30 is received.

within the compression chamber member 18 eccentrically so that the outer diameter 45 of the rotor contacts the cylindrical inner diameter 46 of the member 18 at one point 48 around its circumference. The point 48 is known as the point or line of tangency and consists of an axially extending line of contact from end cap to end cap. The location of point 48 is controlled by maintaining the distance B the same on both the compression chamber 18 and the end caps 13 and 16, the dimension B being the distance from the center of the pin 62 to the tangency point 48. Thus the pressure loading area A of the tangency seal 48a is controlled. The vanes 37 project from the outer diameter 45 of the rotor until the shoes 38 are brought into contact with the inner diameter 46 of the member 18 thereby dividing the space between the rotor and the member 18 into four quadrants. The area of each of the quadrants changes as the rotor rotates. As each quadrant approaches the line of tangency, the area encompassed thereby becomes smaller, compressing any fluids entrapped therein.

The line of tangency 48 divides the compression chamber into high pressure and low pressure sides. In the embodiment illustrated in FIG. 2, the rotor rotates counter-clockwise and an exit port 49 is placed on the high pressure side of the tangency line 48 adjacent thereto. The area upstream of the line of tangency 48 will contain fluid under considerable pressure during the operation of the compressor while the area immediately downstream or to the low pressure side will have a considerably lower pressure. In order to maintain the pressure drop across the line of tangency without excessive pressure flow therebetween, it is necessary that the outer diameter 45 of the rotor 30 contact the inner diameter 46 of the compressor cylinder member 18 at the line of tangency. To the extent that contact is not at a zero clearance during operation, a pressure leak will occur which reduces the efficiency of the compressor considerably.

In order to obtain the desired zero clearance between the rotor and cylinder wall, it is necessary to index the cylinder member 18 with respect to the end caps 13 and 16 to an extremely close tolerance. Such tolerances are difficult to maintain on a production line.

This invention overcomes this difficulty by providing a hinged connection between the end caps and the cylindrical member. Blind bores 60 are provided in the opposed faces of the end caps at a position circumferentially spaced from the desired tangency point. Complementary blind bores 61 are provided iri the radial thickness of the compressor member 18 at a complementary point. Pins 62 are positioned in the bores 60 and 61 so as to hang the member 18 from the end caps. The compressor is assembled by first assembling the end caps, cylindrical member, rotor and shaft assemblies loosely together with the pins 62 received in the bores 60 and 61. Thereafter, the pivotable connection is moved to bring the outer diameter of the rotor into contact with the wall 46 of the cylinder at the tangency point. Correct placement of the hinge connections assures that contact between the rotor and the cylinder will be at the desired point of tangency. The distance B in FIG. 2 and the area A illustrates the relationship between the location of the tangency point and the seal pressure balance area. Suitable test checks may be developed which will provide for proper setting of the tangency clearance or pressure of contact so that the proper zero clearance will be achieved when the compressor is operating. Thereafter, with the end caps and cylindrical member 18 maintained at the set position, the bolts 17 are tightened to lock the assembly together. It can therefore be seen that this invention provides for tangency clearance control which is not dependent upon close tolerance parts construction.

In FIG. 2 a tangency seal 48a is illustrated in place along the line of tangency. The seal may be received in a groove which is ported as at 48b to provide a pressure release from the bottom of the groove whereby the seal may be pressure backed against the rotor. The hinge connection allows the setting of a desired preload against this seal at the time of assembly.

In order to maintain the assembly in the desired set position, increased thickness lands 65 are provided circumferentially around the cylindrical member 18. The lands 65 have grooves 66 therein through which extend the bolts 17. The bolts 17 are received in the grooves 66 with clearance. A locking member 68 is provided for one or more of the-grooves 69 circumferentially spaced from the pivot connections. The locking member 68 is a cylindrical tube having an outer diameter equal to the dimension of the groove 69 so as to be snugly received therein. The ends 70 and 71 of the locking member 68 have bevelled knife edges thereon. The locking member 68 is dimensioned to be axially longer than the space between the opposed faces of the end caps when they are in assembled relationship.

The end cap 16 has associated therewith a plurality of increased radial dimensioned bosses 75 thereon, circumferentially spaced from one another to provide bottoming points for the nut heads 76 of the bolts 17. These lands 75 have grooves 78 associated therewith to receive the shank of the bolts 17 with the heads 76 on the outer side thereof.

The land 75b adjacent the groove 69 which receives the locking member 68 has its corresponding groove 78b dimensioned smaller than the groove 69 so that the knife edge 70 associated with the locking member will bite into the inner surface of the land 75b of the end cap 16 adjacent the groove 78b when the assembly is tightened together. The opposing knife edge 71 of the locking member 68 will bite into the inner face 80 of the end cap 13 circumferentially around the bolt 17b. In this manner, the positioning of the cylindrical member 18 with respect to the end caps to the desired tangency clearance which is done while the bolts 17 are loose, will be maintained after they have been tightened by the connecting action of the locking member 68.

After the compressor has been initially assembled and run for a desired period of time, inspection standards may be set to determine if wear has occurred at the tangency line resulting in a pressure loss. When this occurs, the compressor may be partially disassembled and the bolts 17 loosened to where the locking action of the locking member 68 ceases. Thereafter, the end caps and cylindrical member 18 may again be adjusted by moving them with respect to one another at the pivotable connection to obtain a new tangency clearance setting. Thereafter, tightening the assembly will restore it to an operating condition without the heretofore necessary expense of extensive re-machinin g or parts replacement.

It can therefore be seen from the above that my invention provides for an improved rotary vane compressor wherein the rotor is supported by end caps pivotably connected to the compressor chamber defining member whereby the rotor may be swung on the pivotable connection with respect to the chamber defining member to provide for precise setting of the tangency line location. and tangency clearance. Further, my invention provides for a locking member to maintain the desired setting.

Although the teachings of my invention have herein been discussed with reference to specific theories and embodiments, it is to be understood that these are by way of illustration only and that others may wish to utilize my invention in different designs or applications.

I claim as my invention:

1. A rotary vane compressor comprising an interiorly cylindrical compressor chamber defining member, a rotor having vanes associated therewith eccentrically received in said member, end caps closing the ends of said member in contact with end walls of said rotor, one of said end caps having a plurality of threaded openings therein radially outwardly from the said rotor, said'openings facing the other of said end caps, the said other of said end caps having a plurality of abutting surfaces aligned with said openings, a plurality of bolts having heads abutting the said abutting surfaces and threaded portions received in the said holes whereby the said bolts may be tightened to enclamp the said member between the said end caps and the said member having grooves in the outer diameter thereof in which the bolts are received to restrict excessive rotation of the said member with respect to the said end caps, hinged connections between the said member and the said end caps, the hinged connections comprising an axially aligned pivot point connection between the said member and each of the said end caps, the said rotor supported by the said end caps in fixed relation thereto, the said hinged connection allowing pivotability between the said member and the said end caps along a given are line whereby the said rotor may be moved within the said member to bring its outer diameter into contact with the inner diameter of the said member along a given line of tangency, and a locking means positioned between said end caps for preventing further relative movement between the end cap and said member when the said bolts-are tightened, the said locking means entrapped between the said end caps.

2. A rotary vane compressor comprising: a cupshaped housing, a first end cap assembly closing the open end of said housing, a second end cap assembly positioned within said housing, means for fastening said second end cap assembly to said first end cap assembly in spaced-apart relation, a compressor chamber defining member entrapped between said end cap assemblies having an open interior, a rotor supported by said end cap assemblies within said open interior eccentric to said member, a hinge connection between said member and each of said end caps whereby said member may be arcuately moved around said hingeconnection to contact the outer diameter of said rotor, and means for maintaining the said member in position with respect to the said rotor and end caps, said means including a device having knife edges adapted to cut into portions of the said end cap assemblies to lock the said member in position relative to the said end cap assemblies.

3. A constant volume rotary vane compressor comprising: a cup-shaped housing, a first end cap assembly closing the open end of said housing, a second end cap assembly positioned within said housing, means for fastening said second end cap assembly to said first end cap assembly in spaced-apart relation, a compressor chamber defining member entrapped between said end cap assemblies having an open interior, a rotorsupported by said end cap assemblies within said open interior eccentric tosaid member, hinge connections between said member and each of said end cap assemblies whereby said member may be arcuately moved relative to said end cap assemblies around said hinge connections to contact the outer diameter of said rotor to complete an operational constant volume orientation of the member and the rotor:

means for enclamping said end cap assemblies onto said member; and locking means positioned between, and entrapped between said end cap assemblies when they are enclamped onto said member by said enclamping means to lock said member in position with respect to said rotor and end cap assemblies to prevent movement of the member relative to the end cap assemblies and to maintain the operational constant volume orientation permanently as long as said enclamping means maintain the end cap assemblies enclamped on said member.

4. A constantrvolume vane compressor comprising:

a member defining a compressor chamber and having opposite end faces;

an eccentric rotor having vanes associated therewith in said member;

end assemblies facing said faces enclosing said member in said chamber and rotatably supporting the rotor;

means for enclamping said end assemblies onto said faces;

a pivotable connection between said member and said end assemblies whereby the position of said rotor within said member can be adjusted into optimal constant volume orientation operative relation to the member by pivotal movement of the member and said end assemblies relative to one another before said enclamping means enclamp the end assemblies onto said member faces; and

means entrapped between said end assemblies locking said member in said position relative to said rotor as an incident to enclamping of said end assemblies onto said member by said enclamping means to prevent any relative repositioning of the rotor with respect to the member after assemblyas long as the enclamped condition persists said last mentioned means being positioned between said end assemblies

Claims

1. A rotary vane compressor comprising an interiorly cylindrical compressor chamber defining member, a rotor having vanes associated therewith eccentrically received in said member, end caps closing the ends of said member in contact with end walls of said rotor, one of said end caps having a plurality of threaded openings therein radially outwardly from the said rotor, said openings facing the other of said end caps, the said other of said end caps having a plurality of abutting surfaces aligned with said openings, a plurality of bolts having heads abutting the said abutting surfaces and threaded portions received in the said holes whereby the said bolts may be tightened to enclamp the said member between the said end caps and the said member having grooves in the outer diameter thereof in which the bolts are received to restrict excessive rotation of the said member with respect to the said end caps, hinged connections between the said member and the said end caps, the hinged connections comprising an axially aligned pivot point connection between the said member and each of the said end caps, the said rotor supported by the said end caps in fixed relation thereto, the said hinged connection allowing pivotability between the said member and the said end caps along a given arc line whereby the said rotor may be moved within the said member to bring its outer diameter into contact with the inner diameter of the said member along a given line of tangency, and a locking means positioned between said end caps for preventing further relative movement between the end cap and said member when the said bolts are tightened, the said locking means entrapped between the said end caps.

2. A rotary vane compressor comprising: a cup-shaped housing, a first end cap assembly closing the open end of said housing, a second end cap assembly positioned within said housing, means for fastening said second end cap assembly to said first end cap assembly in spaced-apart relation, a compressor chamber defining member entrapped between said end cap assemblies having an open interior, a rotor supported by said end cap assemblies within said open interior eccentric to said member, a hinge connection between said member and each of said end caps whereby said member may be arcuately moved around said hinge connection to contact the outer diameter of said rotor, and means for maintaining the said member in position with respect to the said rotor and end caps, said means including a device having knife edges adapted to cut into portions of the said end cap assemblies to lock the said member in position relative to the said end cap assemblies.

3. A constant volume rotary vane compressor comprising: a cup-shaped housing, a first end cap assembly closing the open end of said housing, a second end cap assembly positioned within said housing, means for fastening said second end cap assembly to said first end cap assembly in spaced-apart relation, a compressor chamber defining member entrapped between said end cap assemblies having an open interior, a rotor supported by said end cap assemblies within said open interior eccentric to said member, hinge connections between said member and each of said end cap assemblies whereby said member may be arcuately moved relative to said end cap assemblies around said hinge connections to contact the outer diameter of said rotor to complete an operational constant volume orientation of the member and the rotor: means for enclamping said end cap assemblies onto said member; and locking means positioned between, and entrapped between said end cap assemblies when they are enclamped onto said member by said enclamping means to lock said member in position with respect to said rotor and end cap assemblies to prevent movement of the member relative to the end cap assemblies and to maintain the operational constant volume orientation permanently as long as said enclamping means maintain the end cap assemblies enclamped on said member.

4. A constant volume vane compressor comprising: a member defining a compressor chamber and having opposite end faces; an eccentric rotor having vanes associated therewith in said member; end assemblies facing said faces enclosing said member in said chamber and rotatably supporting the rotor; means for enclamping said end assemblies onto said faces; a pivotable connection between said member and said end assemblies whereby the position of said rotor within said member can be adjusted into optimal constant volume orientation operative relation to the member by pivotal movement of the member and said end assemblies relative to one another before said enclamping means enclamp the end assemblies onto said member faces; and means entrapped between said end assemblies locking said member in said position relative to said rotor as an incident to enclamping of said end assemblies onto said member by said enclamping means to prevent any relative repositioning of the rotor with respect to the member after assembly as long as the enclamped condition persists said last mentioned means being positioned between said end assemblies.