US2613870A - Compressor cylinder head assembly - Google Patents

Description

Oct. 14, 1952 w, BQRGERD 2,613,870

COMPRESSOR CYLINDER HEAD ASSEMBLY Filed May 26, 1949 Patented Oct. 14, 1952 William F. Borgerd, Evansville,-Ind., assignor to International Harvester Company, a corporation of New Jersey Application May 26, 1949, Serial No. 95,425

This invention-relates to compressorsused in refrigerators and the like, and more particularly to valve structures for the intake of gas into a compressor cylinder and the discharge of compressed gas therefrom;

"In conventional compressors which employ 7 Claims. (Cl. 230-230) reciprocating pistons expanded gas is drawn from the crank case of the compressor to the cylinder where the gas is compressed and then discharged. Inasmuch as the crank case is generally filled with lubricating oil the gas frequently carries a slug of oil-with it to the cylinder. This is undesirable since the oil, being of greater density than the gas, will be hampered in its passage from the cylinder, causing abnormal stresses and strains on the valve parts. Hence, it is one of the objects of this invention to provide a discharge valve structure capable of accommodatings'lugs of'oil. The volumetric efficiency of small compressors used in refrigerators is notoriously poor. The

. volume ofrefrigerant gas actually pumped is quietly with a resultant smaller cylinder "clear Fig. 2. is a view similar to Fig. 1, but showing the discharge valve ringin its discharge position.

Fig. '3 is' anenlarged detail view showing the cylinder head spacer. I

Referring to the drawings inwhich like characters designate like elements in the-various views, a compressor cylinder head assembly is shown which includes a' cylinder block lo'having a counterboredportion H to form anintern-al annular shoulder or bearing surface 12- anda longitudinally extending portion l3; I

A cylinder I4 is disposed within the cylinde block 10 and is concentric with the cylinder block counterbored portion II.- A piston (not shown) is adapted to reciprocate within the cylinder H. The cylinder l4 has a plurality of circumferentially spaced radially. extendinginlet ports I5 located approximately midway between its longitudinally spaced ends. Apertures or ports l5 are provided to insure an adequate volume of refrigerant gas within the cylinder It on the compression stroke'of the piston A flange l6 projects radially outwardly to provide a portion I! to bear on annular shoulder or bearing surface l2. It will be noted that cylinder [4 is stiff enough to. be supported atone end only. Radially inwardly of the portion I1, the flange [6. has a portion [8 provided with a plurality of. circumferentially spaced substantially longitudinally extending apertures or inletopenings l9. Apertures l9 form inlet passageszor justable. to allow a variation in clearancevolume and that isthin yet-strong so that the volume represented by the discharge holes throughthis plate is at the very minimum. 1 V F .A still further object is the provisionxof a ,withinthe cylinder in such a manner that lthe temperature will be maintained within'safe .working limits lwithout vthe utilization of separate power consuming coolingmeans.

' cylinder head which dissipates heat generated Still another object is the provision of anovel supporting structure for the valveplate.

Anotherobject is the provision of novel guide means for the discharge valve ring. v

A still further object is to provide a cylinder head spacer whichprevents gas leakage from the cylinderand also provides a novel seating means for the inlet valve ring. 1

, The foregoing and other important objects and .desirable features inherent in and encompassed by the invention together with many of thepurposes and uses thereof will become readily apparent from a reading of the ensuing description in conjunction withthe annexed drawings; 4

. lilguljsa plan view showing a portion of .the @compressor in section;

openingsito the cylinder. .I4 fromc-.=the space 20 located between the interior surface 2l'i'of the cylinder block I 0 and the-outer: surface '22 .of

the cylinder l2. Space 20 communicates with ports l5 and the crankcase (not shown).

Positioned within the counterbored portion H on flangeflfi. and having its outer. peripheral surface 23 abutting the internal surface of the longitudinally extending portion I3 is a ring-like cylinder head'spacen-lil; Referring .tD-.E'ig.-.l=3, twosurfaces 25 and 26 each have a continuous smallbead of lead alloy ,(or othersoft metal) 21 fused thereon to function as a seal preventing 'gas leakage from the cylinder l2. The. spacer -24 has a radially inwardly projecting tapered flange portion 28, the lower surface 29..of'which .is inclined upwardly andinwardly as viewedzin Figs. 1 and 3 for a purpose'which will bet-explained hereinafter.

. pl A thin circular flexible valvering "30 ;concentrio with-cylinder i2 is positionedbetween-the .lowersurface 29 of flange portion 28 and flange It. In one position, during the. compression strokeof the piston, the valve ring 30 coversfl'ap- .ertures or-openings IS in flange portion 3.. It is to be understood, that valve ring 30 takesthe form of a flat ring when-no external forces are acting upon it. The outer periphery 3| of valve ring 30 is enclosed in an annular grooveq32 formed bya portion 33 of lower, surface..29 and the cylinder flange 5.. :Referring to Fig. 3, the

3 detail view of the spacer 24, it will be notedthat the annular surface 3'4-has a longitudinal dimension just long enough to give ample space for valve ring 30 to be lightly held on its outer periphery. On the intake stroke of the piston a vacuum is developed within the cylinder which causes valve rin 3D to dish? upwardlyrto uncover openings [9. Thus, theinner annular edge 35 tends to twist or move longitudinally upwardly as viewed in Fig. 1 since the outer. edge or, periphery 3| is confined in the annular groove 32. The valve ring 30 tends to undish and close openings l9 when the vacuum within the cylinder Wis-removed; pwer urfac 2 l n u wardlvaudl uwardly. opr amplelclearance for the innerannular edge 35 to flex slongitudinally to uncover openings Hl-andallowa flow of efriseranteas hroug he t l eno hatg...- hQ% fi on tu na m e of he inner an u r d i fl s s r neclto ever smal monn ltoinsl e ea t possi e olu in: he inletvahe poc e li-u i et ports as stated ab larle.pr dedz ea he ott mu fthe piston stroke to insure complete filling of the cylinder I 4 v even though some small flow restriction sle per enced thr u h. op n n s It w hezapparent that with his; inlet valve construction a veryueconomical.and quiet operating structu e ispmvided.

Positloned-overthe spacer 2.4 and being adapt,- ed. tq, abut the same isa circular valve plate 31. Valve plate ;3,'l. has a plurality of circumferentiallyspaced discharge openings tttherethrolleh toallow compressed gas to be discharged from the. cylinder M. Valveplate 371 relatively thin as compared to conventional valve plates in similar compressorsw-here the thickness varies from %'..1to /2' thick. Obviously the difference .in thickness. between the present valve plate and the .prior conventional plates represents clearance volume saved. Furthermore, the resistance togas-flow. through the discharge openings.- 38 is 'reducedconsiderably by making comparatively thin.

Longitudinally spaced from the valvehplate isa cylinder-head 39 .having aisurfaceilfl rounded or contouredto conformto the internal wall other. Thus it willbe apparent that by supportthe valve plate 41 .Of' the .cylinder compressor housing 42 partially shownrinfFig. l. The cylinder head 39 abuts the; wall 4-l.--.to..save..spaceiand to'obtain the sbest possible-heatdissipation of the compressed gases. With.thisheadconstruction theihea't has a direct metal-to metal flow to theexternalsurroundings ofthe :compressor without the need ofaipower consuming cooling system. The'head 39 .has a centrally located downwardly depending 7 boss. 42! projecting inwardly toward the cylinder Aland a plurality of lcircumferentially spaced boltireceiving holes 43. Means are provided for iclampingxthe cylinder l 4 on the internal annular :shoulder l2 of the cylinder block Ill-which in- The other end-ofmember 41 is received in-a threaded aperture 49 in the-boss 42. As stated .previou51y,'the.valve plate 3.1. is relatively thin ing the valve plate .31 at its center a structurally strong device is provided which will withstand the action of the variable cylinder pressure on .one side and the compressed gas pressure on the other side. It willalso be noted that the heat developed within the cylinder may be conducted from the supporting means, to the cylinder head,

to the housing, and then to the external surroundings.

When assembling the valveplate 31 to the cylinder head 39 any desireddegree of centertightening can be obtained since the valve plate 31 can be rotated. as little as a quarter turn when approaching the final positionif .four bolts 43 are used. The valve plate 3*i can thus be adjusted or deformed to give a little more ora littleless dish .so that its clearance from the piston top in its top dead center position can be made very small.

A discharge valve ring'50 concentricwith and encircling the valve plate supporting structure is positioned over the discharge openings 38 to cover them. The valve ring 5ll is capable, of moving longitudinally but is restrained from moving transversely by four or more feet 5 extendin from reinforcing ribs 58 in the cylinder head and a valve guide 5 I. The valve guide 51 is a circular plate concentric with and secured to the support-. ing member 4?. Its radially disposed outwardly facingperiph'eral surface 52 acts as a sliding surfacefor the inner edge of the valve ring=50. A helical spring 53 abuts the valve "ring 53 and the underside of cylinder head 39 to urge said valve ring Elton the valve plate 37 to a valve closed position.

.A resilient stop means is provided to permit a maximum amount of area for the passage of an oil slug if such should be discharged from the cylinder. In normal operation of the compressor therefrigerant enters'throughinlet ports [5 and openin s I9 during the suction stroke-of the piston after which it is compressed and forced through discharge openings 38 to a discharge pipe (not shown). In compressing the refrigerant and forcing itfthrough the, discharge openings 38, the valve ring 50, which is normally positioned; as shown in Fig. 1, and which Iisv maintained in such position by the helical spring 53 until sufflcient pressure .is.;-exe rted against the spring 5.3, is moved longitudinallyupwardly as viewed in Fig. 1 to uncover openings 3B,.permittinga flow of refrigerant therethrough; The longitudinal movement of valve ring 50 is limited by abuffer plate 54 longitudinally spaced from the valve plate 31 ands'upported on the valve guide 5|. The buffer plate 54 has a radially projecting portion55 overhanging the peripheral surface 52 of the valve guide 51 iwhich' contacts the valve ring 50 and prevents. further longitudinal movement of-said valve firing 50 aw ay from the valve plate 31.; Buffer plate 54j is slidably mounted on supporting memberdl. A star 'or leaf spring 56 abuts the undersideof boss 42" and bufier'plate 54 to urge the bufierplate 54 onthe valveg'uide 5 I. The spring 56 has a greater compressive strength than the helical spring 53 and will normally maintain the buffer plate-543mmmovable. However, should a slug of lubricating oil be discharged throughthe openings 38 the valve ring 50 is permitted toabut the projecting portion 55 of the bufier plate 54-and-move'it longitudinally compressing-star spring 56 to pro-e videa large discharge areafor the passage of the slug. 1 i It will be apparent from the foregoing description that a valve structure mounted in a cylinder head assembly has been provided which is particularly advantageous for use in refrigerator compressors since it is more eiiicient in operation and considerably quieter than valves in known-compressors.

The embodiment of the invention chosen for the purposes of illustration and description hereinis that preferred,-keeping in mind the requirements for achieving the objects 'of'the invention and developing the utility'thereof in a most desirable manner, due regard being had to existingfact'ors of economy, simplicity of design' and construction, production methods and the improvements to be effected. It will be ap-' *preciated, therefora that the particular-strum tural and functional aspects emphasized herein arenot intended toexclude," but rather to suggest, such other advantages and modifications of the invention as fall within the spirit and'scope of the invention as defined in the. appended claims. v 1 v What is claimed is: I

1. In a compressor, the combination comprising a cylindrical housing; a cylinder block counlterbored at one end to form an internal annular shoulder and a longitudinally extending portion; a c'ylinder concentric with said counterbore having a plurality of circumferentially spaced;'ra-

'dially extending apertures between its longi- 'tudi'nally spaced ends, said cylinder having 'a radially projectingffiange at one'end, said flange having a portion adapted to --bear" on said annular "shoulder" and a second portion radially inwardly' of said bearing portion provided with a plu-,

'ralityof circumferentially spaced; substantially longitudinally extending apertures; "a ring-like "spacer positioned on said flange having its outer peripheral surface abutting'the. interior surface of" said longitudinally extending portion, said spacer having'a lower surface inclined upwardly "and inwardly; a circular 'valve ring concentric with said cylinder and positioned between said lower surface andsaid "flange beingadapted to close said longitudinally extendingapertures'in one position,'said valve ring havingits outer periphery enclosed in an annular'groove formed by a portion of said lower surface and said flange whereby said valve ring is capable of twisting aboutits outer periphery to a second position wherein said apertures are'open; a cylinder head having a surface contoured to'conform to the in- "terior wall of said housing and being adaptedcto abut the same, said head having acentrally located boss projecting inwardly toward said cylinderi a" valve plate being adapted to abut said "spacer and having a' pluralityof circumferential-- 1y spaced openings; means tdcla'mp said-cylinder on said internal annular shoulder including a plurality of threadedbolts extending through aligned openings in said head and valve plate to engage threaded bolt receiving apertures 1n "saidlongitudinally extending portion of said cylinder block; valve plate supportingmeans comprising a threaded member secured to a central portion of said valve plate andheld in a threaded aperture in said boss; a discharge valve ring. con- 'centric' with said supportingmeans, said discharge -valve ring being =positioned overt said va'ziilve r alate openings and: being adapted to move longitudinally away from 'sai'd-i valve:;plate;,. an

first springa'butting said head and said discharge valve ring to urgesaid ring on said valve plate, said'spring being helically wound and of greater diameter than said boss; a discharge valve ring guide concentric with and secured to said supporting means and having its radially disposed outwardlyfacing peripheral surface adapted to provide a sliding surface for said discharge valve ring; and resilient stop means to limit the longitudinal movement of said discharge valve ring, said means comprising a buffer plate longitudinally' spaced from said valve plate and supported on and concentric with said valve guide, said buffer plate having a, radially extending portion overhanging the outer peripheral surface of said valve guide and being adapted to slide longitudinally on said'supporting means for said valve plate, a second spring of greater compressive strength than said first spring abutting said boss and said buffer plate to urge said'buffer plate on said valve guide.

2. In a compressor, the combination comprisinga cylindrical housing; a cylinder .blo'ck having a counterbored portion at oneend to form a bearing surface; a cylinder disposed within said block having a radially projecting annular flange at one end, said flange having a portion adapted to be supportedon said bearing surface and having a plurality of circumferentially spaced inlet openings inwardly of'said bearing surface; a spacer comprising a ring having an outside diameter substantiallyequal tothe inside diameter of said counterbore, said spacer being adapted to bear on said flange and be positioned within said counterbore, said spacer having a radially inwardly projecting tapered'flange'por- 'tion; an inlet valve ring positioned between said tapered flange portion and said flange on said cylinder being adapted to close saidinlet openings; a cylinder head having a surface contoured to conform to the interior wall of said housing and being adapted to abut the same, said head having a centrally located boss projecting inwardly toward said cylinder; a valve plate being adapted to abut said spacer and having a plurality of circumferentially spaced discharge openings; means to clamp said cylinder on said counterbored portion including a plurality of threaded bolts extending through alignedopem'ngs in said head and valve plate to engage threaded bolt receiving apertures in said cylinder block; valve plate supporting means comprising a threaded member secured to a central portion of said valve plate and held in a threaded aperture in said boss a discharge valve ring concentric with said supporting means, said valve ring being positioned over said discharge openings and being adapted to move longitudinally away from said valve plate; a first spring abutting said head'and said discharge valve ring to urge said ring on said valve plate, said spring being helically wound and I of greater diameter than said boss; a valve ring guide concentric with and secured to said supporting means and having its radially disposed outwardlyfacing peripheral surface adapted to provide a sliding surface for saidvalve ring; and resilient stop meanstto limit the longitudinal movement of said discharge valve ring, said means comprising a buffer plate longitudinally spaced from said valve plateand supported on and concentric with said valve guide, saidbufier plate having a radially extending portion overhanging the outer peripheral surface of said valve guide and-being adapted to slide longitudinally nou ai suan ine mea o id ra el atera

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