US3807907A

US3807907A - Hermetic motor-compressor

Info

Publication number: US3807907A
Application number: US00381627A
Authority: US
Inventors: E Gannaway
Original assignee: Copeland Corp LLC
Current assignee: Copeland Corp LLC
Priority date: 1970-01-27
Filing date: 1973-07-23
Publication date: 1974-04-30
Anticipated expiration: 1991-04-30

Abstract

A hermetic motor-compressor assembly includes a direct-coupled motor and compressor spring mounted as a unit in a sealed container. The compressor is of the four cylinder Scotch yoke type, with two pairs of opposed coaxial cylinders at right angles on horizontal axes, the pistons of the opposed aligned cylinders being paired by means of a rigid combined yoke and dual connecting rod assembly. The yokes are actuated by rectangular slide blocks fitted on a common crank throw. The yokes and blocks are keyed against displacement with respect to the axes of the cylinders. Suction gas is separated from entrained liquid and guided downwardly in paths close to the motor and through connected passages in the compressor body and out at the bottom.

Description

United States Patent 1191' Gannaway 1 Apr. 30, 1974 [5 HERMETIC MOTOR-COMPRESSOR 3,167,293. 1/1965 Stenger 417/902 1 2-122-322 2/122; 11;:1i:;;;;; 211/21: 73 Assigneez Copeland Corporation Sidney Ohio 3,577,891 5/1971 Katsuta-shi 417/269 [22] Filed: July 1973 Primary ExaminerC. J. Husar [2]] Appl. N 381,627 Attorney, Agent, or Firm -John C. L. Cowen Related US. Application Data v [63] Continuation of Ser. NO. 259,694, June 5, 1972, [57] ABSTRACT abandoned Continuation-impart of Sen N04 A hermetic motor-compressor assembly includes a di- 1970- rect-coupled motor and compressor spring mounted as a unit in a sealed container. The compressor is of the [52] 1.1.5. C1 417/415, 417/312, 417/534, four Cylinder Scotch yoke type, with two pairs of 417/902 posed coaxial cylinders at right angles on horizontal [51] lift. C1. F041) 17/00 axes, the pistons of the Opposed aligned cylinders [58] Field Of Search 417/312, 313, 360, 415, being paired by means of a rigid combined yoke and 417/534 902 dual connecting rod assembly. The yokes are actuated by rectangular slide blocks fitted on a common crank [56] References C'ted throw. The yokes and blocks are keyed against dis- UNITED STATES PATENTS placement with respect to the axes of the cylinders. 2,893,626 7/1959 Weibel 417/312 Suction g is separated from n r ined liquid and 2,823,850 2/1958 Hintz 415/415 guided downwardly in paths close to the motor and 2,965,289 2/1960 Weibe1..,.. 417/902 through connected passages in the compressor body 3,008,629 11/1961 Gertis .1 417/902 and out at the bottom, 3,031,861 5/1962 McCormack 417/902 3,101,891 8/1963 Frank 417/312 5 Claims, 13 Drawing Figures 7/ 74 7 7a /2 II II ATENTEDAPR 30 1914 SHEET 1 UF 5 MTENTEDAPREIO m4 3'807'907 SHEET 2 0F 5 PATENTEDAPRBO m4 7 SHEET 3 [IF 5 PAIENTEDmso 1914 HERMETIC MOTOR-COMPRESSOR This is a continuation, division, of application Ser. No. 259,694, filed June 5, 1972 now abandoned.

BACKGROUND OF THE INVENTION This application is a continuation-in-part of my prior application Ser. No. 6,158, filed Jan. 27, 1972, now U.S. Pat. No. 3,695,786.

The objects of the present invention can be summarized as to provide an improved hermetically sealed motor-compressor assembly designed for refrigeration service and which incorporates, to a degree which is high in proportion to the cost of the unit, the following characteristics, to wit: low noise, effective separation of liquid entrained with returning gas, efficient cooling of the motor, compactness, and rugged, reliable construction, and to provide improved lubrication with reduced likelihood of drawing oil into the .valves of compressors designed to be employed in refrigeration service.

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

BRIEF DESCRIPTION OF THE FIGURES OF DRAWING FIG. 1 is a vertical diametric sectional elevational view of a refrigeration motor-compressor of the hermetic type, incorporating a preferred form ofthe invention;

FIG. 2 is a cross section taken substantially on the line ll-II of FIG. I, and looking in the direction of the arrows;

FIG. 3 is a fragmentary sectional view of the compressor body with other parts omitted, takensubstantially as indicated by the line and arrows III.III on FIG. 2;

FIG. 4 is a fragmentary elevational view of the body, with other parts removed, taken substantially as indicated by the line and arrows lV-IV on FIG. 1;

FIG. 5 is a cross section taken substantially on the line V-V of FIG. 1 and looking in the direction 'of the arrows;

FIG. 6 is a sectional detail taken as indicated by the line VI-VI of'FIG. 1, and looking in the direction of the arrows, but with the crank throw in a different position;

FIG. 7 is a fragmentary'diametric sectional view on a larger scaleof the valve mechanism and associated parts;

FIG. 8 is a bottom plan view of the discharge valve retainer;

FIG. 9 is a bottom plan view of the compressor body;

FIG. 10 is a plan view of the discharge baffle plate;

FIG. 11 is,a plan view of the discharge cover;

welded casing of a refrigeration motor-compressor containing in its upper portion, on a vertical axis, an induction-type electric motor generally designated 12, the armature shaft 14 of which projects downwardly from the electric motor and is formed with an integral crankshaft portion 15 having a single throw 16 which is of sufficient axial length to accommodate two Scotch yokes 20, 21 mounted side-by-side thereon in perpendicular horizontal planes.

The compressor body 22 is formed as a rigid casting boredtransversely to provide two pairs of coaxial cylinders, one pair, comprising

cylinders

24, 25, being aligned with the upper yoke 20 and having

pistons

26, 27 rigidly connected to the yoke 20 by colinear connecting rod portions 28, 29, while the cylinders 30, 31 of the other pair, upon an axis perpendicular to the axis of

cylinders

24, 25, have their pistons 32, 33 similarly with radial ears 38 which carry horizontally arranged helical compression springs 40 trapped between and coacting with spaced inwardly projecting arms 43 of U-brackets 42 secured to the interior of the casing 10 to absorb torsional forces. The ears 38 are internally threaded conformably to, and to receive, the springs 40, but mid convolutions of each spring are distorted, as by having a different lead, so that when fully threaded into the centered position the spring is frictionally held. A rubber-like cup 44 is fitted over each end of each spring to further reduce sound conduction to the case.

A web section 45 of the' body 22 positioned between the motor and compressor sections carries a central bearing neck 46 for the shaft. A bottom discharge cover 50 secured to the body by machine screws as 52 incorporates a bottom bearing 54 for the shaft and also includes discharge chamber areas 55 communicating with coacting discharge cavity portions as 56 in the body, such portions being proportioned to provide FIG. I2 is a vertical longitudinal sectional view of a DETAILED DESCRIPTION OF PREFERRED FORMS OF THE INVENTION Reference character 10 designates generally the sleeve 66 has an inwardly projecting flange 67 at its upper end bounding a relatively large central opening 68 leading into the interior of the sleeve 66 from the upper interior of the casing. A dished shield and spring locating member 70 overlies the opening 68 and is secured as by tack welds, designated 72, to the flange 67, the principal area of the overlying flange portion 7 of the member 70 being spaced above the, flange 67, thereby providing an annular horizontal entrance opening for the suction gas between the flanges 67, 74. The flange 67 is defined by a depressed top portion of the shielding sleeve 66 so that the entrance 75 is surrounded by an annular upwardly bulged bead 76. Oil

and/or liquid refrigerant which may be entrained with the returning suction gas tends to fall to the oil. sump area at the bottom of the casing, but if any droplets are carried upwardly and radially inwardly toward the entrance 75, their inertia will be such that they are guided away from the entrance by the bulge 76 sothat as a practical matter only dry gas finds its way intothe space within the sleeve 66.

The sleeve 66 is somewhat outspaced from the stator 36, so that the space within the sleeve around the motor communicates with channels 77 formed in the inner wall of the supporting portion 34 of the body and extending downwardly from its top to the space 78 below the stator inside the support portion 34. The support portion 34 and sleeve 66 are impervious, and the downflowing gas travels not only through the space around the stator, but also through the space between the stator and the armature, and through additional passages as 80 in the armature. The increased cross sectional area for gas flow provided by the paths around the motor reduces the pressure drop in the motor section yet guides the returning gas in close wiping engagement with the motor, to achieve maximum cooling of the motor from the residual heat absorbing capacity of the gas. The reduced pressure drop offsets the tendency of the compressor to pull oil out through any bearing clearance and into itself where objectionable noise and/or valve damage might occur.

A perforated baffle plate 79 in support portion 34 and spaced above web 45 creates a muffling chamber 81. The holes 84 in plate 79 are proportioned to tune the muffling chamber 81 for maximum sound deadening consistent with efficient operation. Vertical passages 82 in the body 22 have their tops open in the upper surface of web 45 in chamber 81, and conduct the gas via passages 82 and communicating horizontal passages 83 to the suction spaces 87 in the cylinder heads. Ring-type suctionvalves 85 admit gas to the cylinders on the suction strokes, and centrally positioned discharge valves 88 admit the compressed gas to head compression chambers 90. The annular reed type discharge valves 88 are loosely fitted (e.g.: 0.0060.01O

' inch clearance) on the hub portion 86 of the discharge valve retainer 89 which is of T-section and which is secured to the outer face ofthe valve plate by an axial rivet 91. Thus the movement of compressed gas into the head is unobstructed. The valve is biased against its seat on the plate by a spring 93 between the valve and the head of the retainer. Due to the fact that the valve is formed of thin material, and due to the aforementioned clearance between the retainer hub and the hole in the valve, it has been found feasible to dispense with the more conventional cage-type retainer without loss of reliability of valve operation. Compression chambers 90 communicate via passages 92 with the discharge muffling chamber 56, from which the gas is conducted through holes 57 in discharge baffle plate 58 into mufflering chamber portions 55 in discharge cover 50 and thence to the connecting discharge tube 95 leading to the discharge fitting 96 on the exterior of the casing. Additional sound deadening is caused by the fact that the oil in the sump constituted by the bottom of casing engages the exterior of the parts which define the muffling chambers 55, 56.

Each of the yokes 20, 21 is actuated by a rectangular slide block 100, 101. The slide blocks are journaled on the throw 16, and are slightly spaced from each other therealong, and from the cheeks 1'7, 19 of the crankshaft.

In the preferred construction shown, each connecting rod portion is integral with its piston, and an axial hole 102 is drilled through the piston and connecting rod to receive a screw 104 which secures the piston and connecting rod to the yoke, as shown in FIG. 1. The slide block is prevented by the crank throw from rocking around the cylinder axis, and a keying device comprising a U-shaped sheet metal member 105 is secured to the yoke and is provided with flat side arm portions 106, 107 overlying the yoke and the block and preventing any relative displacement of the yoke and block. In the construction shown, the U-shaped keying member 105 has its bight portion clamped between the yoke and the connecting rod, where it is held when the screw 104 is tightened, as shown in FIG. 1. Two of the keying devices 105 are provided for each yoke, one clamped to each connecting rod, so that movement of the parts in any plane in a manner which could result in noisemaking contact is effectively prevented. The side portions 106, 107 of each keying device extend the effec tive length of slide block travel.

Oil is conducted to the bearing areas through an offset vertical riser passage 110 in the crankshaft. Oil from the sump area 11 is fed to the riser through a central bottom hole 111 in a disc 112 which closes the bottom of a radial pumping slot 114 formed in the lower end of the shaft and leading to the riser hole. Lateral branch passages 115, 1 16, 117 conduct oil from the riser to the bearings. Above the topmost lubricant feeding passage 117 an upwardly inclined blind continuation passage 118 extends back through and beyond the axis of the shaft to a position near the surface, where it communicates with an upward riser extension passage 119. which is open at the upper end of the shaft. It should be noted that the opening 119' at the upper end of the extension portion 119 of this passage system is above any position where a material pressure drop has occurred due to gas flow through the motor, and is close to and in the path of the main flow of suction gas entering through inlet 68. Thus a desirable (and substantially balanced) pressure is maintained at the upper and lower ends of the lubrication system, and the tendency to draw oil from the lubricant passage system is further reduced by the ram effect exerted onthe upper end of the riser by the velocity head of the inflowing suction gas. Gas which has been dissolved in the oil nevertheless escapes through the opening 119' but the oil is effectively retained.

FIGS. 12 and 13 illustrate a belt-driven yoke-type compressor, the construction of which is fully disclosed in my prior application Ser. No. 6,158, filed Jan. 27, 1970. The lubrication system includes two oil sumps, comprising a high-pressure sump contained in the discharge cover 126 and from which oil for lubrication of the working parts is forced by the discharge pressure through a capillary tube 128 into a lower pressure sump 130 formed partly in the compressor body 132 and partly in the bottom head 133. The pressure in the low pressure sump exceeds somewhat the pressure existing in the crankcase and at the locations of the working parts, so that the pressure in the low-pressure sump forces the oil through a passage system 134, 135, 136, the passages 136 comprising branches from the crankshaft passage 135 to the bearing surfaces.

From the top of the low-pressure sump 130 a venting passage 140 extends upwardly through the body to the top where it communicates with

continuation passages

141, 142, 143, the latter of which has a mouth 144 which opens into inlet chamber 145 at a position opposite the suction gas inlet to such chamber. The suction gas is delivered to the compressor through a fitting 146 which directs the gas, as indicated by the arrow in H6. 12, in a direction toward the mouth 144, so that the velocity head of the suction gas tends somewhat to augment the pressure at the mouth 144 and oppose an undue reduction, through the vent, of the pressure in the sump 130. The suction gas continues downwardly via passages generally designated 148 to the crankcase area 150 and due to the further pressure drop occurring during its passage to such area it will be recognized that a pressure differential is maintained such that the lubricant is forced to the bearing areas in the manner previously described. The slightly elevated pressure in the sump 130 is maintained or augmented by the above-described action through the vent system.

This Detailed Description of Preferred Forms 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 inventor 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 to comply with administrative requirements of the Patent Office.

What is claimed is:

l. A refrigeration motor-compressor of the type having motor and compressor components enclosed in a sealed container, which container has an inlet through which suction gas is delivered to the interior of the container at a position outside both components, the compressor component having an inlet for receiving gas from the interior of the container, a gas-conducting guide surrounding at least a part of the motor component for guiding suction gas over the motor component to the inlet of the compressor component, the guide having a gas inlet which opens thereinto from the container at a position remote from said compressor component inlet, said guide having an outlet coupled to the inlet of the compressor component in substantially gastight relation, the motor and compressor components of said motor-compressor being arranged substantially coaxially and coupled to a common shaft, the compressor component having a body containing said inlet of the compressor on a side toward the motor component, the guide including a part formed as an integral upward extension of said body and extending away from the compressor component around the motor, characterized by a plurality of generally annular axially spaced partitioning portions located between the motor and compressor components and defining an annular suction muffling chamber having inlet portions opening thereinto from said guide and outlet portions leading to the inlet of the compressor component, one of said partitions being integral with the body and the other partition comprising an orificed plate fitted in and occupying the full cross section of the interior of said extension.

2. A motor-compressor as defined in claim 1 wherein the lower partition is integral with the body and the upper partition is defined by said orificed plate.

3. In a refrigeration motor-compressor including a casing having an oil sump space in a bottom area thereof, a compressor mounted near the bottom therein and having a shaft extending upwardly therefrom within the casing, a motor in the casing above the compressor for driving the shaft, and means for conducting compressed fluid from the compressor and for supporting the compressor and motor as a unit within the casing comprising a generally annular discharge cover secured to the bottom of the compressor, said cover having annularly arranged muffling chamber portions therein, bearing means for said shaft carried by said cover spaced radially inwardly from said chamber portions, an annular upwardly reentrant spring pocket in said cover between said muffling chamber portions and bearing means, oil pumping, pickup and feeding means carried by the shaft and extending downwardly through the bearing meansand into the oil sump space, and a compression coil spring extending upwardly into said pocket from the bottom of the casing and reacting against said cover to support the motor-compressor.

4. A refrigeration motor-compressor assembly of the type having a motor component and a compressor component, said components being enclosed in a sealed container, which container has an inlet through which suction gas is delivered to the interior of the container at a position outside both components, the compressor component having an inlet for receiving gas from the interior of the container, a gas-conducting guide surrounding at least a part of the motor component for guiding suction gas over the motor component to the inlet of the compressor component, the guide having a gas inlet which opens thereinto from the container at a position remote from said compressorcomponent inlet, said guide having an outlet coupled to the inlet of the compressor component in substantially gastight relation, the two components being directcoupled by coaxial vertical shaft portions, the inlet to the guide being generally coaxial with the shaft portions at the motor end, characterized by diverting means carried by the guide and surrounding the inletthereto for deflecting heavier constituents away from said inlet, said guide including an inturned annular flange at its upper end defining a central inlet orifice, the diverting means including anupwardly extending rim portion surrounding and outspaced from said orifice, and a shield overlying said orifice and extending outwardly toward but spaced from the rim portion and spaced above the orificed portion of the flange.

5. A motor-compressor as defined in claim 4 wherein said shield and guide are rigidly secured to said components, and spring locating means on said shield and extending into but spaced from the periphery of said orificc.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent 3, 807,907 Dated April 3Q, 1974 Invent0r(X) Edwin L. Gannaway It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 8, "1972" should be 1970 Column 2, line 61, "7" should be 74 Column 3, line 59, "connecting" should be connected Signed and sealed this 27th day of Augns t 1974.-

(S EAL) Attest:

MCCOY Mo GIBSON, JR. C. MARSHALL DANN Attesting Officer Commissioner of" Patents FOP-M [JO-1050 (M9) USCOMM-DC suave-ps9 UTS. GOVERNMENT PRINTING OFFICE: 15, 0-36533

Claims

1. A refrigeration motor-compressor of the type having motor and compressor components enclosed in a sealed container, which container has an inlet through which suction gas is delivered to the interior of the container at a position outside both components, the compressor component having an inlet for receiving gas from the interior of the container, a gasconducting guide surrounding at least a part of the motor component for guiding suction gas over the motor component to the inlet of the compressor component, the guide having a gas inlet which opens thereinto from the container at a position remote from said compressor component inlet, said guide having an outlet coupled to the inlet of the compressor component in substantially gas-tight relation, the motor and compressor components of said motor-compressor being arranged substantially coaxially and coupled to a common shaft, the compressor component having a body containing said inlet of the compressor on a side toward the motor component, the guide including a part formed as an integral upward extension of said body and extending away from the compressor component around the motor, characterized by a plurality of generally annular axially spaced partitioning portions located between the motor and compressor components and defining an annular suction muffling chamber having inlet portions opening thereinto from said guide and outlet portions leading to the inlet of the compressor component, one of said partitions being integral with the body and the other partition comprising an orificed plate fitted in and occupying the full cross section of the interior of said extension.

3. In a refrigeration motor-compressor including a casing having an oil sump space in a bottom area thereof, a compressor mounted near the bottom therein and having a shaft extending upwardly therefrom within the casing, a motor in the casing above the compressor for driving the shaft, and means for conducting compressed fluid from the compressor and for supporting the compressor and motor as a unit within the casing comprising a generally annular discharge cover secured to the bottom of the compressor, said cover having annularly arranged muffling chamber portions therein, bearing means for said shaft carried by said cover spaced radially inwardly from said chamber portions, an annular upwardly reentrant spring pocket in said cover between said muffling chamber portions and bearing means, oil pumping, pickup and feeding means carried by the shaft and extending downwardly through the bearing means and into the oil sump space, and a compression coil spring extending upwardly into said pocket from the bottom of the casing and reacting against said cover to support the motor-compressor.

4. A refrigeration motor-compressor assembly of the type having a motor component and a compressor component, said components being enclosed in a sealed container, which container has an inlet through which suction gas is delivered to the interior of the container at a position outside both components, the compressor component having an inlet for receiving gas from the interior of the container, a gas-conducting guide surrounding at least a part of the motor component for guiding suction gas over the motor component to the inlet of the compressor component, the guide having a gas inlet which opens thereinto from the container at a position remote from said compressor component inlet, said guide having an outlet coupled to the inlet of the cOmpressor component in substantially gas-tight relation, the two components being direct-coupled by coaxial vertical shaft portions, the inlet to the guide being generally coaxial with the shaft portions at the motor end, characterized by diverting means carried by the guide and surrounding the inlet thereto for deflecting heavier constituents away from said inlet, said guide including an inturned annular flange at its upper end defining a central inlet orifice, the diverting means including an upwardly extending rim portion surrounding and outspaced from said orifice, and a shield overlying said orifice and extending outwardly toward but spaced from the rim portion and spaced above the orificed portion of the flange.

5. A motor-compressor as defined in claim 4 wherein said shield and guide are rigidly secured to said components, and spring locating means on said shield and extending into but spaced from the periphery of said orifice.