Search Images Maps Play YouTube News Gmail Drive More »
Sign in
Screen reader users: click this link for accessible mode. Accessible mode has the same essential features but works better with your reader.

Patents

  1. Advanced Patent Search
Publication numberUS3663127 A
Publication typeGrant
Publication dateMay 16, 1972
Filing dateNov 30, 1970
Priority dateNov 30, 1970
Also published asCA948164A1, DE2159099A1
Publication numberUS 3663127 A, US 3663127A, US-A-3663127, US3663127 A, US3663127A
InventorsRobert J Cheers
Original AssigneeTecumseh Products Co
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Hermetic compressor oil cooling system
US 3663127 A
Abstract
A hermetic motor-compressor unit of the vertical shaft type having an electric motor mounted above and driving the gas pump of the unit. The motor has its main stator winding wound radially inwardly of the auxiliary or start winding so that the end turns of the main winding are directly in the path of the lubricating oil which is flung from the outlet or outlets of a crankshaft oil passage fed from an oil pump in the sump of the compressor. The relatively cool oil thus directly impinges against and drains downwardly along the main winding to thereby effect more efficient cooling of the motor.
Images(2)
Previous page
Next page
Claims  available in
Description  (OCR text may contain errors)

United States Patent Cheers 51 May 16, 1972 [54] HERMETIC COMPRESSOR OIL COOLING SYSTEM [72] Inventor: R0hertJ.Cheers,Tecumseh,Mich.

[73] Assignee: Tecumseh Products Company, Tecumseh,

Mich.

[22] Filed: Nov. 30, 1970 [21] Appl.No.: 93,550

[52] US. Cl ..417/372,417/415, 417/902, 310/54 [51] Int. Cl. ..F04b 17/00, F04b 35/00, F04b 39/02, H021: 9/00, H02k 9/20 [58] Field of Search ..4l7/415, 410, 372, 902; 310/54 [56] References Cited UNITED STATES PATENTS 2,435,108 l/l948 Touborg ..417/372 X 3,075,106 1/1963 Chi ..3l0/54 X Primary Examiner-Robert M. Walker Attorney-Bames, Kisselle, Raisch & Choate ABSTRACT A hermetic motor-compressor unit of the vertical shaft type having an electric motor mounted above and driving the gas pump of the unit. The motor has its main stator winding wound radially inwardly of the auxiliary or start winding so that the end turns of the main winding are directly in the path of the lubricating oil which is flung from the outlet or outlets of a crankshaft oil passage fed from an oil pump in the sump of the compressor. The relatively cool oil thus directly impinges against and drains downwardly along the main winding to thereby effect more efficient cooling of the motor.

7 Claims, 3 Drawing Plgures PATEHTEDMM 18 I972 SHEET 1 BF 2 INVENTOR POBE/PTJCHEEPS ATTORNEYS PATENTEDMY 16 1972 .ililEl 2 UF 2 INVENTOR POEE/QTJ. CHEERS ATTORNEYS HERMETIC COMPRESSOR OIL COOLING SYSTEM This invention relates to hermetic compressors and more particularly to an improved oil cooling system for the electric motor of the compressor.

Cooling of hermetic refrigeration motors is important to the efficiency and life of the compressor. In the past, two methods which have been used generally to cool hermetic motors are oil recirculation and refrigerant gas circulation, usually augmented by some type of centrifugal pump and/or fan within the unit. Also, it has been conventional practice to employ in hermetic compressors electric motors which are wound with the main winding or windings of the stator radially outwardly of the start winding or windings and these windings have been separated by various types of insulation. Hence when the oil and refrigerant gas delivered from the centrifugal device or devices impinges upon the windings, very little of this cooling medium reaches the main windings because it is blocked by the start windings and by the insulation between start and main windings.

The problem of motor cooling becomes most critical for those models of hermetic compressors designed for use in low temperature applications because of the poor conductivity of the low density refrigerant gas which is relied upon in part to effect cooling of the motor winding by conducting motor heat to the hermetic casing of the compressor. In such applications, the liquid oil contained in the hermetic casing must be relied upon more heavily to effect cooling of the winding. Hence it is important that this oil be circulated in the most efficient manner possible relative to the principal heat source which, during normal or running operation of the compressor, comprises the main winding of the motor stator. At this time the stator start winding does not generate any significant amount of heat.

Accordingly, it is an object of the present invention to provide an improved hermetic compressor construction wherein the cooling oil delivery system and motor windings are arranged relative to one another to promote more efficient cooling of the motor without increasing the cost of the compressor, thereby improving the operational efficiency of the compressor.

Other objects, features and advantages of the present invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings wherein:

FIG. I is a vertical sectional view taken on the line I[ of FIG. 2 illustrating an exemplary but preferred embodiment of a hermetic compressor constructed in accordance with the present invention, a portion of the hermetic casing and refrigerant intake being shown in side elevation.

FIG. 2 is a horizontal sectional view taken on the line II-II of FIG. 1.

FIG. 3 is a fragmentary vertical sectional view taken on the line II||II of FIG. 2.

Referring in more detail to the accompanying drawings, FIG. I illustrates a twin cylinder hermetic compressor which, except for the stator winding and oil circulating structure, is conventional and well-known in the art. For example, compressor 10 may comprise a I970 Model AH compressor constructed commercially by Tecumseh Products Company of Tecumseh, Michigan, assignee of the present invention, and sold under the trademark TECUMSEH. Accordingly, compressor 10 has the usual two par1 hermetically sealed steel casing 12, a twin cylinder refrigerant gas pump I4 and superposed electric motor resiliently suspended as a unit in the casing, a one piece vertically oriented crankshaft-motor shaft 16 and a rotor l8 of motor 15 secured to the upper end of shaft 16 for rotating the same. A stator 20 of motor I5 is suitably supported stationarily on pump 14 and has a conventional laminated core 22 with axial slots 24 (FIG. 2) opening to the inner periphery 26 of the stator in which are wound the main or run winding(s) and start or auxiliary winding(s) of the electric motor in a manner described in more detail hereinafter. Preferably motor 15 is a single-phase alternating current induction type commonly employed in hermetic oompressors and may be either the two-pole type shown herein or a four-pole type, with the stator windings wound in a distributed manner in slots 24.

Shaft 16 is journalled at its lower end in a bearing 28 to which is attached a stationary portion of a centrifugal oil pump 30 of conventional construction which in a well-known manner cooperates with radial passages in the pump and lower end of shaft I6 to pump oil from the liquid refrigerant-oil sump 32 at the bottom of the casing I2 into and upwardly through a central oil-conducting passageway in shaft 16. This passageway includes a passage 34 extending upwardly coincident with the axis of shaft 16 to a point above the upper end of an inboard bearing 38 and about even with the lower surface 40 of the rotor core 42. The oil passageway also includes a slightly larger diameter passage 43 communicating at its lower end with the upper end of passage 34 and extending upwardly in shaft 16 coincident with the axis thereof to an outwardly flared outlet at the upper end of the shaft formed by the beveled surface 44, as best seen in FIG. 3. A pair of diametrically opposite radial slots 46 and 48 are formed across the upper end of shaft 16 (FIG. 2). The upper end of rotor 18 preferably has an end ring 50 provided with a series of upright radially extending blades 52 which rotate with rotor 18 and are arranged in a semi-circular row concentric with the upper end of shaft 16, the blades being juxtaposed to the usual balancing counterweight 53.

The main or run winding of stator 20in the two-pole version illustrated herein consists of a left winding 60 and a right winding 62 (as viewed in FIG. 2) electrically interconnected as one main or run winding and an auxiliary or start winding consisting of a left winding 64 and a right winding 66 (as viewed in FIG. 2) also electrically interconnected as one winding. In accordance with one feature of the present invention, the start windings 64 and 66 are wound in their respective core slots 24 prior to the winding of run windings 60 and 62 so that the start windings are disposed radially outwardly of the run windings as best indicated in FIG. 1. A sheath 68 of Mylar or other suitable electrical insulating material is then placed around the exposed end turns of start windings 64 and 66 to insulate them from the main windings 60 and 62 which are wound against but radially inwardly of the start windings. The start and run windings may be wound in distributed fashion through the same slots 24 in which they have hitherto been wound in previous compressor motors of this type by suitable automatic winding machines well known in the art. Hence the upper end turns 70 and 72 of start windings 64 and 66 respectively and the upper end turns 74 and 76 of run windings 60 and 62 respectively are arranged as shown in FIGS. 1, 2 and 3 with end turns 74 and 76 disposed radially inwardly of end turns 70 and 72 and projecting axially slightly thereabove. In addition, the run winding end turns 74 and 76 project axially beyond the end surface 77 of ring 50 by a distance about equal to the axial projection of the upper ends of blades 52 from the upper end surface 79 of core 22. In the example illustrated herein, the upper end surface 78 of shaft 16 is located about one-fourth inch below surface 77, but it is to be understood that end surface 78 may be generally flush with surface 77 or even project thereabove by as much as five-eighths inch.

In operation of compressor 10, when the start and run windings of the motor are energized rotor 18 is rotated to drive shaft 16 which in turn produces reciprocation of the pistons 80 and 82 of the compressor in the usual manner. Rotation of shaft 16 causes pump 30 to pump oil from the sump 32 upwardly in passage 34 as indicated by the arrows in FIG. I. Some of the lubricating oil flowing up passage 34 is diverted to lateral oiling passages (not shown) in shaft 16 which feed oil to the connecting rod and piston wrist pin bearings in the usual manner. Another such oiling port 96 (FIG. I) diverts a portion of the oil from passage 34 and feeds it to helical external passages (not shown) in the portion of shaft 16 passing through bearing 38 for lubrication of this bearing. A portion of the oil stream is thus diverted from passage 34 and is eventually flung radially outwardly from the upper end of bearing 38 as indicated by the arrows in FIG. 1. The oil leaving the upper end of bearing 38 impinges against the inner peripheral surface 84 of the lower end ring 85 of rotor 18 which is formed as a series of fan blades. Surface 84 is thus interrupted so that the oil is dispersed and thrown off outwardly between the fan blades and radially outwardly against the lower end turns 86 and 88 of run windings 60 and 62 respectively, to thereby help cool the run windings. This oil cooling augments the cooling effect of the refrigerant gas entering the casing at inlet port 90. The whirling rotor 18 and the suction at intake 91 induces a flow of refrigerant gas downwardly and inwardly through the annular space between end turns 86 and 88 and the upper surface 92 of crankcase 94 of compressor 14 which produces a gas flow upwardly through the cylindrical clearance space between rotor 18 and the inner periphery 26 of core 22.

The remainder of the oil which is pumped past port 96 flows up passage 34 and then up passage 43 to the upper end outlet 44 of shaft 16 from which it is flung radially outwardly by the centrifugal action of the whirling shaft. The oil is further impelled by blades 52 which act not only as a centrifugal fan on the refrigerant gas but also fling off any oil striking the blades so that there is a constant cone-like spray of oil leaving blades 52 and being flung against as well as over the encircling upper end turns 74 and 76 of run windings 60 and 62. This oil drains by gravity down over the motor windings and stator and finds its way back to the sump 32, some oil draining along the inner wall of the casing 12 and some draining through the oil return opening 100 in the top wall 92 of the crankcase 94. As the oil drains back, it is cooled by contact with the casing walls and by the incoming refrigerant gas (in the disclosed example of a low side casing) so that the temperature of the oil in the sump 32 remains relatively cool compared to the running temperature of the motor windings.

Because the oil flow and oil cooling rate remain relatively constant compared to the density of the refrigerant gas in the casing, the circulating oil provides an effective cooling medium in the compressor which can be relied upon to significantly reduce the temperature of the run windings 60 and 62 of the electric motor. Since run windings 60 and 62 are located radially inward of the start windings 64 and 66, the flow of cooling oil to the run windings is not obstructed and hence the run windings are subjected to a much heavier oil flow over a greater portion of their area. Although the start windings 64 and 66 receive less cooling oil, this does not pose a problem because these windings are in many applications only fully energized for a relatively brief period at compressor start-up, and in most applications do not constitute the primary source of motor heat during running of the compressor. The compressor cooling system of the present invention thus significantly reduces the average operating temperature of the electric motor of the compressor for any given load. Hence compressor is able to run under a more severe loading for a longer period of time, thereby increasing the capacity rating of the compressor without a corresponding increase in the size or cost of the compressor.

1 claim:

1. In a motor-compressor unit having a hermetically sealed casing with communicating motor and compressor chambers, an electric motor arranged in the motor chamber comprising a stator core having run and start windings wound thereon, a rotor disposed within said stator and a motor shaft carrying said rotor for rotation therewith, said motor shaft being drivingly connected to a gas pump of said compressor and having an oil conducting passageway extending axially therethrough, and means for supplying oil from a casing sump to said passageway in said shaft in response to rotation of said rotor, the improvement wherein said start windings are disposed radially outwardly of the portion of said run windings adjacent thereto, said shaft having outlet means connected to said passageway and oriented relative to said run windings such that oil leaving said passa eway via said outlet means is directed toward said run wm tags to effect cooling of the same.

2. The compressor as set forth in claim 1 wherein said run windings have end turns projecting axially beyond at least one axial end face of said stator core and said outlet means comprises at least one outlet located axially between said end face of said core and the axially outermost portion of said end turns.

3. The compressor as set forth in claim 2 wherein said rotor has a plurality of blades thereon disposed radially between said shaft and said end turns of said run windings and located in the path of oil flow from said one outlet to said end turns.

4. The compressor as set forth in claim 2 wherein said shaft is oriented upright, said motor is disposed above said gas pump and said sump is disposed below said gas pump.

5. The compressor as set forth in claim 4 wherein said one outlet is located at the upper end of said shaft and said end turns comprise the upper end turns of said run windings.

6. The compressor as set forth in claim 5 wherein said outlet means includes a second outlet leading from said passageway to a space in said motor chamber below said rotor and stator core, said run windings having lower end turns projecting beneath said stator core into the path of oil emerging from said second outlet.

7. The compressor as set forth in claim 1 wherein said run and start windings are wound in distributed fashion through a plurality of said slots on said core such that said run winding has first and second end turns projecting respectively axially beyond the axially opposite ends of said stator core and each of said end turns is arranged as an annulus concentrically encircling said shaft, and said outlet means comprises first and second outlets oriented to direct oil from said passageway radially outwardly toward said first and second end turns respectively.

* s s t a

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US2435108 *Dec 18, 1943Jan 27, 1948Tecumseh Refrigeration Sales ARefrigeration compressor
US3075106 *Mar 9, 1961Jan 22, 1963Gen ElectricDynamoelectric machine
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3922114 *Jul 19, 1974Nov 25, 1975Dunham Bush IncHermetic rotary helical screw compressor with improved oil management
US4370104 *Jul 22, 1980Jan 25, 1983White Consolidated Industries, Inc.Suction muffler for refrigeration compressor
US4384635 *Jun 11, 1980May 24, 1983Tecumseh Products CompanyContinuous curvature noise suppressing compressor housing
US4388756 *Nov 25, 1980Jun 21, 1983General Electric CompanyMethods of making improved rotor assembly
US4396361 *Jan 31, 1979Aug 2, 1983Carrier CorporationSeparation of lubricating oil from refrigerant gas in a reciprocating compressor
US4478559 *Jul 9, 1981Oct 23, 1984Aspera S.P.A.Compressor with ducted crankshaft having a grooved end for oil distribution
US5101931 *May 23, 1990Apr 7, 1992Copeland CorporationDischarge muffler and method
US5222874 *Jan 9, 1991Jun 29, 1993Sullair CorporationLubricant cooled electric drive motor for a compressor
US5228843 *Sep 21, 1990Jul 20, 1993Intreprinderea De Frigidere GaestiCompressor for domestic refrigerators
US5252039 *Dec 2, 1991Oct 12, 1993Matsushita Refrigeration Co.Enclosed motor-driven compressor
US5322419 *Apr 20, 1993Jun 21, 1994Arctic S.A.Compressor for domestic refrigerators
US5468360 *Sep 9, 1994Nov 21, 1995David; Lennie F.Electrolytic chlorination
US5538404 *Mar 17, 1995Jul 23, 1996Bristol Compressors, Inc.Compressor unit shell construction
US6401472 *Dec 21, 2000Jun 11, 2002Bitzer Kuehlmaschinenbau GmbhRefrigerant compressor apparatus
US6680550 *Jan 14, 2002Jan 20, 2004Matsushita Electric Industrial Co., Ltd.Hermetic motor-driven compressor
US7075399 *Mar 23, 2004Jul 11, 2006Hamilton Sunstrand CorporationLiquid-cooled inductive devices with interspersed winding layers and directed coolant flow
US7210912 *Jun 17, 2004May 1, 2007Tecumseh Products CompanyReciprocating piston compressor having improved noise attenuation
US7759828 *Sep 7, 2007Jul 20, 2010Sullair CorporationIntegrated electric motor driven compressor
US8138652Aug 22, 2008Mar 20, 2012Sunco Investments LimitedMultistage variable reluctance motor/generator
US8198762 *Jan 31, 2008Jun 12, 2012Pratt & Whitney Canada Corp.Winding end turn cooling in an electric machine
US8242646 *Nov 6, 2008Aug 14, 2012Toyota Jidosha Kabushiki KaishaRotating electric machine and drive device
US8310124Feb 16, 2012Nov 13, 2012Sunco Investments LimitedMultistage variable reluctance motor/generator
US8317489 *May 16, 2006Nov 27, 2012Bitzer Kuehlmaschinenbau GmbhRefrigerant compressor
US8415843 *Sep 7, 2010Apr 9, 2013Johnson Electric S.A.Brushless motor
US8575816 *Jun 2, 2008Nov 5, 2013Acc Austria GmbhCoolant compressor
US8753098 *Jun 26, 2009Jun 17, 2014Mitsubishi Electric CorporationRefrigerant compressor
US8937413Oct 9, 2012Jan 20, 2015Chrysler Group LlcElectric motor with coolant shield assembly
US20040189429 *Mar 23, 2004Sep 30, 2004Saban Daniel M.Liquid-cooled inductive devices with interspersed winding layers and directed coolant flow
US20040223854 *Jun 17, 2004Nov 11, 2004Tomell Phillip A.Reciprocating piston compressor having improved noise attenuation
US20100119388 *Jun 2, 2008May 13, 2010Helmut ZeinlingerCoolant Compressor
US20100237725 *Nov 6, 2008Sep 23, 2010Kazutaka TatematsuRotating electric machine and drive device
US20110057523 *Sep 7, 2010Mar 10, 2011Yong Bin LiBrushless motor
US20120107151 *Jun 26, 2009May 3, 2012Mitsubishi Electric CorporationRefrigerant compressor
CN101832252A *May 5, 2010Sep 15, 2010奉化市天风汽车空压机有限公司Energy-saving automobile water-cooling air compressor
CN102013780BSep 7, 2009Mar 12, 2014德昌电机(深圳)有限公司Miniature brushless motor
DE2617369A1 *Apr 21, 1976Nov 3, 1977Danfoss AsGekapselter motorverdichter fuer kaeltemaschinen
EP0179799A1 *Mar 18, 1985May 7, 1986Beckman Instruments IncCentrifugal oil pump flow proportioning and cooling system.
WO2003089793A1 *Dec 27, 2002Oct 30, 2003Hong Sog-KieStructure for reducing refrigerant flow loss in compressor
Classifications
U.S. Classification417/372, 417/902, 417/415, 310/54
International ClassificationF04B39/02, F04B39/06, F04B35/04, H02K9/19, F25B31/02
Cooperative ClassificationH02K9/19, Y10S417/902, F04B39/06, F25B31/02, F04B35/04, F04B39/0246
European ClassificationF04B39/06, F04B35/04, F04B39/02T1D1, F25B31/02, H02K9/19