US2825499A - Refrigerating apparatus - Google Patents

Description

M alrch 4, 1958 J GlBSON ETI'AL. 2,825,499

I REFRIGERATING APPARATUS- 2 Sheecs-Sheet 1 Filed May 19, 1954 //v VENTORS. .1 Lowell aim James R. Harnaday I John H.,I-Ieidom I The? .Atforney A March 4, J L. GIBSON HA}. 2,825,499.

REFRIGERATING APPARATUS Filed May 19, 1954 2 Sheets-Sh et 2 lN-I/E/V TORS,

A J Lowell Gibson James R. 'Homaday Jolm H. He/darn REFRIGERATING APPARATUS Lowell Gibson, James R. Hornaday, and John H. Heidorn, Dayton, Ohio, assignors to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application May 19, 1954, Serial No. 430,768

2 Claims. (Cl. 230-19) This invention relates to refrigerating apparatus and more particularly to a refrigerant compressor.

It is an object of this invention to provide a refrigerant compressor which is light weight and compact and which may be operated at widely varying speeds. More particularly it is an object of this invention to provide an axial compressor suitable for use in an automobile air conditioning system wherein the compressor is driven at variable speeds by the car engine and wherein the oil for lubricating the compressor will not be swept out of the crankcase at high compressor speeds.

it is another object of this invention to provide a multiple cylinder compressor which may be manufactured by mass production methods at a low cost.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to. the accompanying drawings, wherein a preferred form of the present invention is clearly shown.

In the drawings: V

Figure 1 is a vertical sectional view of a preferred embodiment of the compressor;

Figure 2 is an end elevational view with parts broken away;

Figure 3 is a fragmentary sectional view taken substan-- tially on line 33 of Figure 2; 7

Figure 4 is a fragmentary sectional view taken substantially on line 44 of Figure 1;

Figure 5 is an end elevational view of the cylinder block and shoe guide;

Figure 6 is a fragmentary sectional view taken substantially on line 6-6 of Figure 5; and,

Figure 7 is a plan view of the intake valve plate.

Referring now to the drawing wherein a preferred embodiment of the invention has been shown, reference numeral 10 generally designates a sheet metal casing which serves as a crankcase for the compressor. Reference numeral 12 designates the compressor drive shaft which is supported by means of a first ball bearing assembly 14 and a second needle bearing assembly 16. The one end of the shaft is adapted to project through the end wall of casing 10 and is provided with a splined portion 18 on which the usual drive pulley (not shown) would be secured. A cast iron bearing support or end bell element 29 is secured to the sheet metal casing 10 and serves to support the ball bearing assembly 14 as shown.

The usual shaft seal assembly 22 is provided for preventing the escape of lubricant and/ or refrigerant along the shaft where it passes through the wall of the casing. Since the construction of shaft seals of this type is well known and since the construction of the seal may be varied without departing from the spirit of my invention, the details thereof will not be described.

The compressor is of the wobble plate or axial type and includes a wobble plate 24 which is supported on an offset or angularly disposed bearing element 26 as shown. The bearing element 26 is secured directly to the shaft 12 so as to rotate therewith and is of the type which causes fired States Patent 0 Patented Mar. 4, 1958 the wobble plate 24 to wobble as the shaft rotates. The wobble plate 24 supports a plurality of brass socket elements 28 which serve to engage the connecting rods 30 as shown. Ball bearings 31 permit relative rotation between the bearing element 26 and the wobble plate 24. For purposes of illustrating the invention, five cylinders have been shown whereas certain aspects of the invention are equally applicable to compressors wherein either a greater or lesser number of cylinders may be provided.

Pistons 32 are adapted to be driven by the connecting rods 30 and operate within bores 34 provided in a cylinder block 36. The cylinder block 36 is provided with a pair of integral projections 38 which serve to guide a shoe 40 carried by the wobble plate 24. By virtue of this arrangement it is obvious that rotation of the drive shaft 12 causes the plate 24' to wobble without rotating whereby the rotary movement of the shaft 12 is converted into reciprocating movement of the pistons 32.

The compressor housing 10 serves as a sump for a quantity of oil to be used in lubricating the compressor. Forced oil circulation is provided by means of an oil pump generally designated by the reference numeral 50. For purposes of illustration the pump has been shown as a gear pump (see Figure 4) whereas any type of oil pump could be used. This pump is adapted to withdraw oil from the bottom of the housing 10 through the tube 52 and to discharge the oil into the shaft seal cavity 55 through an outlet port 54 so as to provide good lubrication and cooling for the shaft seal assembly. In order to provide for the return of oil from the shaft seal cavity back into the crankcase, an oil return passage 56 has been provided as shown through which the oil may flow from the shaft seal cavity through the ball bearing assembly 14 from whence it splashes onto the ball bearings and then back into the crankcase.

A valve plate 60 is provided at the head end of the cylinder block 36 and this valve plate is provided with the usual suction and discharge ports 62 and respectively. Thus the plate 60 includes a plurality of suction ports 62 (see Figure 2) which connect each cylinder with a common suction chamber 64 formed in the cylinder head elemeat 66. The usual type of suction valves are provided in the form of a reed valve disc 68 (see Figures 1 and 7) which is clamped between the valve plate 60 and the cylinder block 36. The disc 68 includes a plurality of reeds 69 which are in alignment with the suction ports 62. Each reed has an aperture 71 in alignment with the corresponding discharge port 70 so as not to interfere with the gas being discharged from the compression chamber. As the pistons 32 move away from the valve plate 60, gas to be compressed will be pulled into the compression chambers and will then be compressed as the pistons move back toward the valve plate and will be discharged through the discharge ports 70 into a common discharge chamber 72 formed in the cylinder head 66. Suitable discharge valves 74 are provided on the plate 66 in accordance with usual practice. The gas to be compressed enters the common suction chamber 64 through a suction line and is required to pass through an orifice 82 which is preferably formed in an insert 84 carried by the cylinder head as best shown in Figures 1 and 3. The design of the orifice 82 is such that the orifice ofiers minimum restriction to the flow of fluid when the compressor is operating at a slow speed and offers more restriction at higher speeds. As the speed of the compressor increases, the velocity of the gas flowing through the orifice 82 will tend to incraese but will not increase in direct proportion to the increase in compressor speed. When the pressure of the gas at the orifice outlet is 58% of the pressure of the gas at the orifice inlet then the velocity of the gas flowing through the orifice is at its maximum. As the speeds-of the compressor increases above a predetermined 7 speed, the design 'of the orifice 82 prevents any further appreciable increase in the amount of gas entering the 7V compressor. V t I i a As bestishown in- F-igure 3t oflth'e' d-rawing ajpassage' 90- 7 has fibee'n. provided which connects the crankcase to the 'suctionpassage: at a point ahead' of the orifice' insert 84" whereby th'eipr'es'sure' in the .crankcaseis maintained sub stantiallygat the'same pressure as that'preva iling intthe:

evaporator." By virtue :of the above d'escr ib ed characteristic-ssoftthe orifice; when" the: compressor is operated at high speeds, the crankcase-will notbe's'ubjected 'to objectionally lowpressures but will be maintained at pressures w cotrresponding very nearly to evaporator pressures;

The compressor i's adapted'tobe used in' an aircon'di tioning systemofthe; general 'typeshown i'n Hull Patent No; 233 6,7 3 3-wherein the compressor is'belted tothe maincanzengine andforms a part of" a? sealed" refrigeration circuit;

While 'thelforin of embodiment of 'the'iri'vention as herein disclosed constitutesa;preferred form; it i'sito be? understood that other forms might-be adopted; as may:

comeewithin the scope of: the claims which fciillovv. What is c'laimediisas followsz' Y 5 tary; movement-of said drive shaft to reciprocating movement' of said piston means said wobble plate having a guide sh-oe thereon, -said cast cylinder block'having in tegrally formed guide means extending 'parallelto thej V inner surfacof said sheet m'etal casing element for guiding V said'shoe 's'aid drfive shaft having a portion projecting" t V throngh said endbellg' a-shaft'sealcarried by'said'en'd bell j of said sheet metal casing element and having'a' plurality of h'orizontal' oylinder bores arrangedabontracentral axis; means forming inlet and outlet'ports for said cylinder.

' bores, valve means fo r] said ports, a east end bell'closing for preventing the escapeof refrigerant andiiliibricafnt' ra'longasaid .drive.shaft,=and a.vgear typeroil pump operated by said drive shaft andabutting a portion of saidtcast end' .7 I bell for pumping oil from said oil sump onto said shaft 7 seal and said wobble plate;

2. In a refrigerant compressor; an open ended tslieet metal casing element, a cast cylinder block closing one end the other *end of said;casing-element and cooperating with 'sump, a drive-shaft '"journalledin said cylinder bl'ock and said end bell, pistgnmansyoperating; in said cylinde'r bores, means including'a wobble plate for converting r rotary movement of said drive shaft to reciprocating movement of said piston rneans,fsaid wobble platethaving a guide-shoe -t11ereon; saidcastcylinder blockhaving in tegrallyg formed guide n'iean s' extending parallel to thef inner surfa'ceofsaidsheet'metal "casing 'elem'ent'for guid ing said sh'oe; a'cylinderhead' havingflani inlet chambers. communicating with sa'id inlet ports"'andhaving an outlet chamber communicating with said outletjports, means 1 760,636 Fermne* s ;r rMa 21, 19.307 "1,889,595 Tursky Oct. 4, 19 32: 2,106,236 'Burk'e Ian, 25,193; Y 2,571,871 Hayes V ofc s, 1951 2,588,261 Magdeburger Mar. 4, 1-952 7 2,603,954 Davis s July 22;;1-952 said cylinder blockand said casing' element to form an oil including a restricted orifice of fixed cross section forming airinletpassage in one'iwa-ll' of 'said cylinder head for Q0111 veyi-ng gastobe" compressed finto'said inle't chamber; and r communicating passage" means *formed' 'in said 'cylindefrhead rand said cast cylinder'blockforminga passage lead- I V ing froin theiinle't side 'ofisa'id'orifice to' said 'oilisump for equalizing tlipressuresihereing' V V V 7 R ferences Cited-in-the'filefof his patenti UNITED STATES PATE TS

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