US3560120A

US3560120A - Rotary compressor

Info

Publication number: US3560120A
Application number: US767030A
Authority: US
Inventors: Edwin L Gannaway; Robert M Draper
Original assignee: Copeland Refrigeration Corp
Current assignee: Copeland Refrigeration Corp
Priority date: 1968-09-09
Filing date: 1968-09-09
Publication date: 1971-02-02
Anticipated expiration: 1988-02-02

Abstract

A VANE-TYPE ROTARY COMPRESSOR IS HOUSED IN A CYLINDRICAL CUP-SHAPED SHEET METAL HOUSING SHELL, THE COMPRESSOR ASSEMBLY COMPRISING THREE MAIN BODY SECTIONS OF GENERALLY CYLINDRICAL FOR INCLUDING A CYLINDRICAL STATOR SECTION SANDWICHED BETWEEN INNER AND OUTER COVERING SECTIONS SEALED IN THE SHELL AND ONE FORMING AN OUTER END CLOSURE WHICH DEFINES A BEARING SUPPORT, A SEAL CHAMBER, AND A SUPPORT FOR A DRIVING CLUTCH AND PULLEY, THE INTERNAL COVER SECTION BEING SPACED FROM THE CLOSED REAR WALL OF THE SHELL AND ACTING AS A REAR BEARING SUPPORT AND ALSO AS A PARTITION FOR A COMBINED OIL SUMP AND HIGH PRESSURE DISCHARGE CHAMBER AND ALSO SUPPORTING THE LUBRICANT FEEDING AND CONTROL MEANS AND THE SUCTION AND DISCHARGE CONDUITS. THE LUBRICATING MEANS COMPRISES A CAPILLARY TUBE FOR FEEDING OIL FROM THE SUMP AND A CENTRIFUGALLY OPERABLE VALVE WHICH CLOSES OFF ESCAPE OF OIL FROM THE SUMP WHEN THE COMPRESSOR IS NOT RUNNING. THE VANES ARE PROVIDED WITH VENT CHANNELS TO THE VANE POCKETS. A SECTION OF THE STATOR WALL WHICH IS ENGAGED BY THE VANES IN THE AREA DEFINING THE SEAL BETWEEN THE HIGH AND LOW PRESSURE REGIONS IS CONCENTRIC AND HAS A CLOSE FIT WITH THE ROTOR, TO PROVIDE A SEAL OF SUBSTANTIAL ANGULAR EXTENT AS DISTINGUISHED FROM A TANGENT SEAL BETWEEN THE ROTOR AND STATOR.

Description

Feb. 2, 1971 W Y ETAL 3,560,120 RQTARY COMPRESSOR v l Original Filed March 18, 1962 .2 Sheets-Sheet 1 E. L. GANNAWAY ETAL Feb. 2, 1971 ROTARY COMPRESSOR Original Filed March 18, 1962 -BY faizrff/fiw z O '/W%? 2 Sheets-Sheet 2 INVENTORS J20! United States Patent Oflice 3,560,120 Patented Feb. 2, 1971 3,560,120 ROTARY COMPRESSOR Edwin L. Gannaway and Robert M. Draper, Sidney, Ohio,

assignors to Copeland Refrigeration Corporation, Sidney, Ohio, a corporation of Michigan Continuation of application Ser. No. 713,581, Mar. 18, 1968. This application Sept. 9, 1968, Ser. No. 767,030 Int. Cl. F04c 29/02; F04d 29/06 U.S. Cl. 41884 4 Claims ABSTRACT OF THE DISCLOSURE A vane-type rotary compressor is housed in a cylindrical cup-shaped sheet metal housing shell, the compressor assembly comprising three main body sections of generally cylindrical form including a cylindrical stator section sandwiched between inner and outer covering sections sealed in the shell and one forming an outer end closure which defines a bearing support, a seal chamber, and a support for a driving clutch and pulley, the internal cover section being spaced from the closed rear wall of the shell and acting as a rear bearing support and also as a partition for a combined oil sump and high pressure discharge chamber and also supporting the lubricant feeding and control means and the suction and discharge conduits. The lubricating means comprises a capillary tube for feeding oil from the sump and a centrifugally operable valve which closes off escape of oil from the sump when the compressor is not running. The vanes are provided with vent channels to the vane pockets. A section of the stator wall which is engaged by the vanes in the area defining the seal between the high and low pressure regions is concentric and has a close fit with the rotor, to provide a seal of substantial angular extent as distinguished from a tangent seal between the rotor and stator.

The present application is a continuation of my previously filed co-pending application Ser. No. 713,581, filed Mar. 18, 1968, now abandoned.

BACKGROUND OF THE INVENTION The present invention relates to compressors, particularly for refrigeration service.

Important objects of the invention are the provision of improved lubricating means for refrigerant compressors, an improved contouring and inter relationship between the rotor and stator portions of vane-type compressors, whereby improved sealing and improved flow characteristics are attained, improved means for preventing unwanted migration of lubricant during 01f cycles of the compressor, an improved overall arrangement and method of assembly of the components of vane-type compressors, an improved external clutch-type drive mechanism, and improved arrangements of the bearing, component mounting means, and vane components thereof.

Other objects and advantages will be apparent upon consideration of the present disclosure in its entirety.

DETAILED DESCRIPTION OF A PREFERRED FORM OF THE INVENTION FIG. 1 is a diametric longitudinal sectional view of a compressor constructed in accordance with the present invention, and

FIGS. 2 and 3 are cross-sectional views taken substantially on the lines II-II and III-III respectively, and looking in the direction of the arrows.

Referring now to the drawing, reference character designates generally a sheet metal shell of cylindrical cross section closed at its rear end by an integral wall 11 and at its other end open to receive the mechanical components of the compressor, which are installed by sliding the completed assembly of compressor components into the casing to the position shown,

The main components of the compressor assembly comprise the cylinder body 12, the front cover section 14 and the rear cover section 15. The cover sections are secured in the cylinder body by through bolts 16 and the entire assembly is secured in the shell by radial screws 18 which extend intosuitably tapped holes in the cover 14 through holes in the shell.

The body 12 has a substantially cylindrical pumping chamber 20 therein of substantially greater diameter than the cylindrical pumping rotor 22 and axially offset therefrom in the usual manner. The Wall of chamber 20 is not strictly cylindrical, however, a portion 21 thereof r in the sealing region being concentric with and closely fitted to rotor 22 throughout a portion (e.g. 45) of the periphery of the latter, that is, approximately from the position X to the position Y as designated in FIG. 2. The axis of rotation of the rotor is centered with respect to the shell while the cylinder and chamber 20 are offset therefrom. The extended sealing portion 21 provides an increased leakage barrier and provides more clearance and reduced gas velocities in the part of the compression chamber near the discharge ports 32.

The rotor is provided with four slidable vanes 25 arranged in non-radial slots 26. The slots and vanes are slanted to incline the vanes forwardly in the direction of rotation, lying tangent to a circle whose radius is approximately three-fifths that of the rotor. A pressure equalizing channel 27 connects the bottom of the vane slot with the cylinder on the trailing side of each of the vanes. Although this could be formed in the slot wall, it is more convenient to form it on the vane, as shown, extending the full distance between its inner and outer edges. When the vane is in the compression area the high pressure is thus able to act under the vane to assist in maintaining vane contact, while when the vane moves into the low pressure area the high pressure under the vane is vented through the channel, reducing load and wear. The channel also permits quick vane projection upon starting and elimintaes bouncing of the vanes.

As shown in FIG. 2, the cylinder body 12 does not fill the internal cross section of the shell. The suction line 28 which is the inlet to the compressor extends through and in sealed relation to the rear wall 11 and is connected to inlet chamber 30 in cover 15 to deliver suction gas to the vane space, wherein it is compressed in the usual manner between the vanes and the converging walls of the stator and rotor, and discharged under pressure through the outlet valves 33 and ports 32 and into chamber 35 lying outside the body 12. Compressed gas passes from chamber 35 through holes 36 in cover 15 into the pressure chamber 38, the bottom of which also constitutes the oil sump.

The rotor 22 is keyed to shaft 40 which is journaled in antifriction bearings 42, 44 in the front and rear covers 1 1, 15, respectively, and projects forwardly to an exposed end to which a hub 60 is secured by a tapered key and nut fastening 62. A flange disc 58 on hub 60 is drivable by an electromagnetically clutchable and declutchable pulley 45 to drive the shaft and rotor. A neck 46 secured to and forming an axial extension of front cover 14 supports the antifriction pulley bearing 50 upon which the pulley is freely rotatable and also supports an electromagnet assembly comprising the annular winding 52 so designed that its principal effective lines of force are directed forwardly through the slotted web portion 54 of the pulley to act upon an axially displaceable annular plate-type armature 55 which is keyed to rotate with the shaft and which when drawn rearwardly by energization of the winding 52 frictionally engages web 54 and so transmits the pulley drive to the shaft and rotor. The

armature 55 is supported for axial movement and held fast rotatively with respect to the shaft, and also biased to the disengaged position, by the strap-type springs 56, each such spring being secured at its outer end to the armature and at its inner end to hub flange 58.

The front cover 14 is formed with a forwardly opening axial seal chamber 66 surrounding the shaft and which is closed by front support 46. Front support 46 is attached to neck 64 by screws 48 which also secure and clamp the Supporting flange 53 for the coil of the electromagnet between parts 64-46. The grooved portion 47 of the pulley overhangs the coil and is aligned with hearing 50 which is in turn supported by the fixed housing portion 46. Thus the entire belt load is taken by the housing and is transmitted in straight compression through the bearing and no lateral loads are imposed on the shaft. In addition if the unit is installed in a situation which subjects it to vibration, as in a motor vehicle, the bearing 50 will 1'0- tate constantly, thereby reducing the tendency to workharden and fret the balls and contacting race areas of the bearing.

The seal assembly, generally designated 70, may be of conventional construction and detailed description thereof will not be required. Its rotary sealing ring 68, which is sealed with respect to the shaft, has a seal-defining running fit against fixed ring 69 which is in turn sealed against the inner peripheral wall of chamber 66.

The high pressure outlet chamber 38 contains an oil feed and control assembly the body 75 of which is secured by screws 74 to the rear face of cover 15. Means is provided for metering oil from the sump to lubricated components at a relatively constant rate when the compressor is running, the flow being motivated by the discharge pressure in chamber 38. Although other known means might be used, our preferred construction incorporates a capillary feed tube 78 having an open lower end submerged in the oil in the sump. The oil which is forced through the tube is carried via a passage 82 to a valve chamber 84 from which its escape is blocked by a ball valve 85 when the compressor is not in operation. When the compressor is operating at normal speed, the valve is opened by centrifugal force developed by flyweight 86. As shown in FIG. 1, the capillary tube 78 is coiled in a chamber 76 defined by a depending open-bottomed tubular portion of body 75 and the lower end of which is protected by a screen 77, the upper end of chamber 76 being closed by a partition 80 through which the upper end of capillary tube 78 projects into communication with passage 82. Valve ball 85 is urged by Spring 88 against its seat 90. Flyweight 86 is pivotally mounted on a pin 92 carried by a rotary disc 104 carried by the rear end of shaft 40. The flyweight moves radially in a plane transverse to the axis in a chamber 94 which encloses the disc and the flyweight is urged radially inward by a hairpin spring 95 and outwardly by centrifugal force when the compressor is in operation. A cam portion 96 integral with the flyweight reacts against an axially slidable follower pin 98 as the flyweight moves outwardly, to unseat the ball 85, while when the shaft is at rest and the flyweight drawn inwardly against stop pin 97 by spring 95, the follower pin 100 and ball 85 are permitted to move to the valve-closed position under the influence of the spring 88.

When valve 85 is open, fluid is forced via chamber 84, passage 100 and chamber 94 to a passage 102 drilled axially through the disc- 104. Housing 75 is sealed against the rear face of cover 15 in the area surrounding chamber 94 and an axial passage 105 drilled in the shaft 40 from the rear end thereof forms a continuation of passage 102 in disc 104. Passage 105 feeds oil through suitable communicating passages and ports as 106, 107, 108, 109 to the seal chamber 65 and to other working parts as shown. All of the pressure drop occurs in capillary tube 78 so that the oil is at low pressure as it enters the seal area and other working parts. This is of advantage from the standpoint of seal life.

When the compressor is used in a refrigeration system, it is normal for some refrigerant in liquid form to be contained with the oil in the sump due to the high pressure in the discharge chamber. As the oil which is thus charged with a certain amount of refrigerant leaves the capillary tube and the high pressure area and enters the lubricant passages 105, etc., which are in low pressure zones, the refrigerant contained in the oil vaporizes and expands, thereby giving a cooling effect on the seal, bearing and other lubricated components.

The oil is only able to return to the sump by escaping past the working surfaces and passing through outlet ports 32, chamber 35 and openings 36 to chamber 38, which acts as an oil separator due to the reduction of velocity and change of direction of the oil-carrying gas entering such chamber. When the compressor stops, closure of the valve prevents migration of oil into the working areas of the compressor under the pressure remaining in chamber 38. Noise and possible damage to the valves and other parts which might be caused by excess oil on subsequent startup are thereby prevented.

This Detailed Description of a Preferred Form of the Invention, and the accompanying drawings, have been furnished in compliance with the statutory requirement to set forth the best mode contemplated by the inventors of carrying out the invention. The prior portions consisting of the Abstract of the Disclosure and the Background of the Invention are furnished without prejudice in an elfort to comply with administrative requirements of the patent What is claimed is:

1. In a compressor having working parts which require lubrication and having an oil sump pressurized by the output, means for delivering a controlled supply of lubricant to the working parts including passage means, flow limiting means for connecting said passage means to the sump, a valve closable to interrupt flow through said pas sage means from the sump, and means including a centrif ugal actuator for opening said valve in response to operation of the compressor and for maintaining the valve in closed position when the compressor is not operating.

2. A compressor as defined in claim 1 wherein said flow limiting means is a capillary tube.

3. A compressor as defined in claim 1 of the type having an accessible shaft drivable by an external power source, rotary sealing parts for preventing leakage along the shaft, and a lubricant chamber surrounding said sealing parts and fed from said passage means, said flow limiting means providing when the valve is open a supply of lubricant to said chamber at a pressure lower than that prevailing in the sump.

4. In a refrigerant compressor having a low pressure zone containing working parts which require lubrication and having a high pressure zone including an oil sump connected to and pressurized by the output of the compressor, means for lubricating and cooling the working parts comprising oil feeding means connecting said sump to such working parts, combined oil conducting and pres sure reducing regulating means including a capillary tube forming a part of said feeding means and also acting as the pressure reducing regulating means and having a uniform diameter which is small in proportion to its length, said tube having its inlet end in said sump and its outlet end connected to the working parts in the low pressure zone.

References Cited UNITED STATES PATENTS 1,558,620 10/ 1925 Kagi 2310-207X 2,496,676 2/1950 IRawson 230-207 3,243,103 3/1966 Bellmer 230207 ROBERT -M. WALKER, Primary Examiner US. Cl. XIR.