Suction duct and scroll compressor incorporating same

A scroll compressor and assembly includes a suction duct to direct refrigerant from the housing inlet to a location upstream of a motor. Additionally, the suction duct includes drain ports that act to drain oil received in the suction duct into the oil sump. This can be used for filling and charging the oil sump with oil initially by using the common refrigerant inlet port through the housing and also acts to collect coalesced oil from oil mist generated by operation of the scroll compressor in a refrigeration system and likewise drain the lubricant oil into the lubricant sump.

FIELD OF THE INVENTION

The present invention relates to scroll compressors for compressing refrigerant and more particularly relates to the suction flow path for refrigerant and/or other such fluids within a scroll compressor.

BACKGROUND OF THE INVENTION

A scroll compressor is a certain type of compressor that is used to compress refrigerant for such applications as refrigeration, air conditioning, industrial cooling and freezer applications, and/or other applications where compressed fluid may be used. Such prior scroll compressors are known, for example, as exemplified in U.S. Pat. No. 6,398,530 to Hasemann; U.S. Pat. No. 6,814,551, to Kammhoff et al.; U.S. Pat. No. 6,960,070 to Kammhoff et al.; and U.S. Pat. No. 7,112,046 to Kammhoff et al., all of which are assigned to a Bitzer entity closely related to the present assignee. As the present disclosure pertains to improvements that can be implemented in these or other scroll compressor designs, the entire disclosures of U.S. Pat. Nos. 6,398,530; 7,112,046; 6,814,551; and 6,960,070 are hereby incorporated by reference in their entireties.

As is exemplified by these patents, scroll compressors conventionally include an outer housing having a scroll compressor contained therein. A scroll compressor includes first and second scroll compressor members. A first compressor member is typically arranged stationary and fixed in the outer housing. A second scroll compressor member is moveable relative to the first scroll compressor member in order to compress refrigerant between respective scroll ribs which rise above the respective bases and engage in one another. Conventionally the moveable scroll compressor member is driven about an orbital path about a central axis for the purposes of compressing refrigerant. An appropriate drive unit, typically an electric motor, is provided usually within the same housing to drive the movable scroll member.

The present invention pertains to improvements in the state of the art.

BRIEF SUMMARY OF THE INVENTION

One inventive aspect is directed toward a scroll compressor in which a suction duct is provided in the housing to direct flow of refrigerant or other such fluid from the housing inlet into a desired location; that also includes at least one drain port that is arranged to drain lubricant received in the suction duct into the lubricant sump at the bottom of the scroll compressor housing. The drain port is advantageous in that the suction duct and the drain port thereof can be used for charging the lubricant sump in the housing through the inlet and/or to facilitate lubricant mist separation prior to gas flow into the motor shell in which coalesced lubricant mist drains through the drain port into the lubricant sump.

According to one aspect, a scroll compressor comprises a housing having an inlet and an outlet and a lubricant sump. Scroll compressor bodies in the housing have respective bases and scroll ribs that project from the respective bases and in which mutually engage. Scroll compressor bodies are operative to compress fluid entering from the inlet and to discharge compressed fluid toward the outlet. A motor provides rotational output directly driving one of the scroll compressor bodies to facilitate relative movement for the compression of fluid. A suction duct in the housing communicates with the housing inlet and has a drain port that is arranged to drain lubricant received in the suction duct into the lubricant sump.

Another aspect is directed toward a method of compressing fluid using a scroll compressor comprising: compressing fluid with a pair of scroll compressor bodies that have respective bases and respective scroll ribs; lubricating the scroll compressor with lubricating fluid from a lubrication sump; ducting fluid for compression through a suction duct to a location upstream of the scroll compressor bodies; and draining lubricating fluid received in the suction duct into the lubrication sump.

Yet another aspect of the present invention is a suction duct that is adapted for mounting in a compressor housing comprising a stamped sheet steel metal body having an outer generally rectangular and arcuate mounting flange surrounding a duct channel that has been pressed into the body and extends between a top end and a bottom end. An inlet opening is formed through a bottom of the duct channel proximate the top end. A drain port is formed proximate a bottom end.

DETAILED DESCRIPTION OF THE INVENTION

An embodiment of the present invention is illustrated in the figures as a scroll compressor assembly10generally including an outer housing12in which a scroll compressor14can be driven by a drive unit16. The scroll compressor assembly may be arranged in a refrigerant circuit for refrigeration, industrial cooling, freezing, air conditioning or other appropriate applications where compressed fluid is desired. Appropriate connection ports provide for connection to a refrigeration circuit and include a refrigerant inlet port18and a refrigerant outlet port20extending through the outer housing12. The scroll compressor assembly10is operable through operation of the drive unit16to operate the scroll compressor14and thereby compress an appropriate refrigerant or other fluid that enters the refrigerant inlet port18and exits the refrigerant outlet port20in a compressed high pressure state.

The outer housing12may take many forms. In the preferred embodiment, the outer housing includes multiple shell sections and preferably three shell sections to include a central cylindrical housing section24, a top end housing section26and a bottom end housing section28. Preferably, the housing sections24,26,28are formed of appropriate sheet steel and welded together to make a permanent outer housing12enclosure. However, if disassembly of the housing is desired, other housing provisions can be made that can include metal castings or machined components.

The central housing section24is preferably cylindrical and telescopically interfits with the top and bottom end housing sections26,28. This forms an enclosed chamber30for housing the scroll compressor14and drive unit16. Each of the top and bottom end housing sections26,28are generally dome shaped and include respective cylindrical side wall regions32,34to mate with the center section24and provide for closing off the top and bottom ends of the outer housing12. As can be seen inFIG. 1, the top side wall region32telescopically overlaps the central housing section24and is exteriorly welded along a circular welded region to the top end of the central housing section24. Similarly the bottom side wall region34of the bottom end housing section28telescopically interfits with the central housing section24(but is shown as being installed into the interior rather than the exterior of the central housing section24) and is exteriorly welded by a circular weld region.

The drive unit16may preferably take the form of an electrical motor assembly40, which is supported by upper and lower bearing members42,44. The motor assembly40operably rotates and drives a shaft46. The electrical motor assembly40generally includes an outer annular motor housing48, a stator50comprising electrical coils and a rotor52that is coupled to the drive shaft46for rotation together. Energizing the stator50is operative to rotatably drive the rotor52and thereby rotate the drive shaft46about a central axis54.

With reference toFIGS. 1 and 4, the lower bearing member44includes a central generally cylindrical hub58that includes a central bushing and opening to provide a cylindrical bearing60to which the drive shaft46is journaled for rotational support. A plurality of arms62and typically at least three arms project radially outward from the bearing central hub58preferably at equally spaced angular intervals. These support arms62engage and are seated on a circular seating surface64provided by the terminating circular edge of the bottom side wall region34of the bottom outer housing section28. As such, the bottom housing section28can serve to locate, support and seat the lower bearing member44and thereby serves as a base upon which the internal components of the scroll compressor assembly can be supported.

The lower bearing member44in turn supports the cylindrical motor housing48by virtue of a circular seat66formed on a plate-like ledge region68of the lower bearing member44that projects outward along the top of the central hub58. The support arms62also preferably are closely toleranced relative to the inner diameter of the central housing section. The arms62may engage with the inner diameter surface of the central housing section24to centrally locate the lower bearing member44and thereby maintain position of the central axis54. This can be by way of an interference and press-fit support arrangement between the lower bearing member44and the outer housing12(See e.g.FIG. 4). Alternatively according to a more preferred configuration, as shown inFIG. 1, the lower bearing engages with the lower housing section28which is in turn attached to center section24. Likewise, the outer motor housing48may be supported with an interference and press-fit along the stepped seat66of the lower bearing member44. As shown, screws may be used to securely fasten the motor housing to the lower bearing member44.

The drive shaft46is formed with a plurality of progressively smaller diameter sections46a-46dwhich are aligned concentric with the central axis54. The smallest diameter section46dis journaled for rotation within the lower bearing member44with the next smallest section46cproviding a step72for axial support of the drive shaft46upon the lower bearing member44. The largest section46ais journaled for rotation within the upper bearing member42.

The drive shaft46further includes an offset eccentric drive section74that has a cylindrical drive surface75about an offset axis that is offset relative to the central axis54. This offset drive section74is journaled within a cavity of the movable scroll member of the scroll compressor14to drive the movable member of the scroll compressor about an orbital path when the drive shaft46is spun about the central axis54. To provide for lubrication of all of these bearing surfaces, the outer housing12provides an oil lubricant sump76at the bottom end in which suitable oil lubricant is provided. The drive shaft46has an oil lubricant pipe and impeller78that acts as an oil pump when the drive shaft is spun and thereby pumps oil out of the lubricant sump76into an internal lubricant passageway80defined within the drive shaft46. During rotation of the drive shaft46, centrifugal force acts to drive lubricant oil up through the lubricant passageway80against the action of gravity. The lubricant passageway80includes various radial passages as shown to feed oil through centrifugal force to appropriate bearing surfaces and thereby lubricate sliding surfaces as may be desired.

The upper bearing member42includes a central bearing hub84into which the largest section46aof the drive shaft46is journaled for rotation. Extending outward from the bearing hub84is a support web86that merges into an outer peripheral support rim88. Provided along the support web86is an annular stepped seating surface90which may have an interference and press-fit with the top end of the cylindrical motor housing48to thereby provide for axial and radial location. The motor housing48may also be fastened with screws to the upper bearing member42. The outer peripheral support rim88also may include an outer annular stepped seating surface92which may have an interference and press-fit with the outer housing12. For example, the outer peripheral rim88can engage the seating surface92axially, that is it engages on a lateral plane perpendicular to axis54and not through a diameter. To provide for centering there is provided a diametric fit just below the surface92between the central housing section24and the support rim88. Specifically, between the telescoped central and top-end housing sections24,26is defined in internal circular step94, which is located axially and radially with the outer annular step92of the upper bearing member42.

The upper bearing member42also provides axial thrust support to the movable scroll member through a bearing support via an axial thrust surface96. While this may be integrally provided by a single unitary component, it is shown as being provided by a separate collar member98that is interfit with the upper portion of the upper bearing member42along stepped annular interface100. The collar member98defines a central opening102that is a size large enough to provide for receipt of the eccentric offset drive section74and allow for orbital eccentric movement thereof that is provided within a receiving portion of the movable scroll compressor member112.

Turning in greater detail to the scroll compressor14, the scroll compressor body is provided by first and second scroll compressor bodies which preferably include a stationary fixed scroll compressor body110and a movable scroll compressor body112. The moveable scroll compressor body112is arranged for orbital movement relative to the fixed scroll compressor body110for the purpose of compressing refrigerant. The fixed scroll compressor body includes a first rib114projecting axially from a plate-like base116and is designed in the form of a spiral. Similarly, the second movable scroll compressor body112includes a second scroll rib118projecting axially from a plate-like base120and is in the design form of a similar spiral. The scroll ribs114,118engage in one another and abut sealingly on the respective base surfaces120,116of the respectively other compressor body112,110. As a result, multiple compression chambers122are formed between the scroll ribs114,118and the bases120,116of the compressor bodies112,110. Within the chambers122, progressive compression of refrigerant takes place. Refrigerant flows with an initial low pressure via an intake area124surrounding the scroll ribs114,118in the outer radial region (see e.g.FIGS. 2-3). Following the progressive compression in the chambers122(as the chambers progressively are defined radially inward), the refrigerant exits via a compression outlet126which is defined centrally within the base116of the fixed scroll compressor body110. Refrigerant that has been compressed to a high pressure can exit the chambers122via the compression outlet126during operation of the scroll compressor.

The movable scroll compressor body112engages the eccentric offset drive section74of the drive shaft46. More specifically, the receiving portion of the movable scroll compressor body112includes a cylindrical bushing drive hub128which slideably receives the eccentric offset drive section74with a slideable bearing surface provided therein. In detail, the eccentric offset drive section74engages the cylindrical drive hub128in order to move the moveable scroll compressor body112about an orbital path about the central axis54during rotation of the drive shaft46about the central axis54. Considering that this offset relationship causes a weight imbalance relative to the central axis54, the assembly preferably includes a counter weight130that is mounted at a fixed angular orientation to the drive shaft46. The counter weight130acts to offset the weight imbalance caused by the eccentric offset drive section74and the movable scroll compressor body112that is driven about an orbital path (e.g. among other things, the scroll rib is not equally balanced). The counter weight130includes an attachment collar132and an offset weight region134(see counter weight shown best inFIG. 2) that provides for the counter weight effect and thereby balancing of the overall weight of the rotating components about the central axis54in cooperation with a lower counterweight135for balancing purposes. This provides for reduced vibration and noise of the overall assembly by internally balancing or cancelling out inertial forces.

With reference toFIGS. 1-3, and particularlyFIG. 2, the guiding movement of the scroll compressor can be seen. To guide the orbital movement of the movable scroll compressor body112relative to the fixed scroll compressor body110, an appropriate key coupling140may be provided. Keyed couplings are often referred to in the scroll compressor art as an “Oldham Coupling.” In this embodiment, the key coupling140includes an outer ring body142and includes two first keys144that are linearly spaced along a first lateral axis146and that slide closely and linearly within two respective keyway tracks148that are linearly spaced and aligned along the first axis146as well. The key way tracks148are defined by the stationary fixed scroll compressor body110such that the linear movement of the key coupling140along the first lateral axis146is a linear movement relative to the outer housing12and perpendicular to the central axis54. The keys can comprise slots, grooves or, as shown, projections which project from the ring body142of the key coupling140. This control of movement over the first lateral axis146guides part of the overall orbital path of the moveable scroll compressor body112.

Additionally, the key coupling includes four second keys152in which opposed pairs of the second keys152are linearly aligned substantially parallel relative to a second traverse lateral axis154that is perpendicular to the first lateral axis146. There are two sets of the second keys152that act cooperatively to receive projecting sliding guide portions156that project from the base120on opposite sides of the movable scroll compressor body112. The guide portions156linearly engage and are guided for linear movement along the second traverse lateral axis by virtue of sliding linear guiding movement of the guide portions156along sets of the second keys152.

By virtue of the key coupling140, the moveable scroll compressor body112has movement restrained relative to the fixed scroll compressor body110along the first lateral axis146and second traverse lateral axis154. This results in the prevention of any relative rotation of the moveable scroll body as it allows only translational motion. More particularly, the fixed scroll compressor body110limits motion of the key coupling140to linear movement along the first lateral axis146; and in turn, the key coupling140when moving along the first lateral axis146carries the moveable scroll112along the first lateral axis146therewith. Additionally, the movable scroll compressor body can independently move relative to the key coupling140along the second traverse lateral axis154by virtue of relative sliding movement afforded by the guide portions156which are received and slide between the second keys152. By allowing for simultaneous movement in two mutually perpendicular axes146,154, the eccentric motion that is afforded by the eccentric offset drive section74of the drive shaft46upon the cylindrical drive hub128of the movable scroll compressor body112is translated into an orbital path movement of the movable scroll compressor body112relative to the fixed scroll compressor body110.

Referring in greater detail to the fixed scroll compressor body110, this body110is fixed to the upper bearing member42by an extension extending axially and vertically therebetween and around the outside of the moveable scroll compressor body112. In the illustrated embodiment, the fixed scroll compressor body110includes a plurality of axially projecting legs158(seeFIG. 2) projecting on the same side as the scroll rib from the base116. These legs158engage and are seated against the top side of the upper bearing member42. Preferably, bolts160(FIG. 2) are provided to fasten the fixed scroll compressor body110to the upper bearing member42. The bolts160extend axially through the legs158of the fixed scroll compressor body and are fastened and screwed into corresponding threaded openings in the upper bearing member42. For further support and fixation of the fixed scroll compressor body110, the outer periphery of the fixed scroll compressor body includes a cylindrical surface162that is closely received against the inner cylindrical surface of the outer housing10and more particularly the top end housing section26. A clearance gap between surface162and side wall32serves to permit assembly of upper housing26over the compressor assembly and subsequently to contain the o-ring seal164. An O-ring seal164seals the region between the cylindrical locating surface162and the outer housing112to prevent a leak path from compressed high pressure fluid to the un-compressed section/sump region inside of the outer housing12. The seal164can be retained in a radially outward facing annular groove166.

With reference toFIGS. 1-3and particularlyFIG. 3, the upper side (e.g. the side opposite the scroll rib) of the fixed scroll110supports a floatable baffle member170. To accommodate the same, the upper side of the fixed scroll compressor body110includes an annular and more specifically cylindrical inner hub region172and an outwardly spaced peripheral rim174which are connected by radially extending disc region176of the base116. Between the hub172and the rim174is provided an annular piston-like chamber178into which the baffle member170is received. With this arrangement, the combination of the baffle member170and the fixed scroll compressor body110serve to separate a high pressure chamber180from lower pressure regions within the housing10. While the baffle member170is shown as engaging and constrained radially within the outer peripheral rim174of the fixed scroll compressor body110, the baffle member170could alternatively be cylindrically located against the inner surface of the outer housing12directly.

As shown in the embodiment, and with particular reference toFIG. 3, the baffle member170includes an inner hub region184, a disc region186and an outer peripheral rim region188. To provide strengthening, a plurality of radially extending ribs190extending along the top side of the disc region186between the hub region184and the peripheral rim region188may be integrally provided and are preferably equally angularly spaced relative to the central axis54. The baffle member170in addition to tending to separate the high pressure chamber180from the remainder of the outer housing12also serves to transfer pressure loads generated by high pressure chamber180away from the inner region of the fixed scroll compressor body110and toward the outer peripheral region of the fixed scroll compressor body110. At the outer peripheral region, pressure loads can be transferred to and carried more directly by the outer housing12and therefore avoid or at least minimize stressing components and substantially avoid deformation or deflection in working components such as the scroll bodies. Preferably, the baffle member170is floatable relative to the fixed scroll compressor body110along the inner peripheral region. This can be accomplished, for example, as shown in the illustrated embodiment by a sliding cylindrical interface192between mutually cylindrical sliding surfaces of the fixed scroll compressor body and the baffle member along the respective hub regions thereof. As compressed high pressure refrigerant in the high pressure chamber180acts upon the baffle member170, substantially no load may be transferred along the inner region, other than as may be due to frictional engagement. Instead, an axial contact interface ring194is provided at the radial outer periphery where the respective rim regions are located for the fixed scroll compressor body110and the baffle member170. Preferably, an annular axial gap196is provided between the innermost diameter of the baffle member170and the upper side of the fixed scroll compressor body110. The annular axial gap196is defined between the radially innermost portion of the baffle member and the scroll member and is adapted to decrease in size in response to a pressure load caused by high pressure refrigerant compressed within the high pressure chamber180. The gap196is allowed to expand to its relaxed size upon relief of the pressure and load.

To facilitate load transfer most effectively, an annular intermediate or lower pressure chamber198is defined between the baffle member170and the fixed scroll compressor body110. This intermediate or lower pressure chamber can be subject to either the lower sump pressure as shown, or can be subject to an intermediate pressure (e.g. through a fluid communication passage200defined through the fixed scroll compressor body to connect one of the individual compression chambers122to the chamber198). Load carrying characteristics can therefore be configured based on the lower or intermediate pressure that is selected for best stress/deflection management. In either event, the pressure contained in the intermediate or low pressure chamber198during operation is substantially less than the high pressure chamber180thereby causing a pressure differential and load to develop across the baffle member170.

To prevent leakage and to better facilitate load transfer, inner and outer seals204,206may be provided, both of which may be resilient, elastomeric O-ring seal members. The inner seal204is preferably a radial seal and disposed in a radially inwardly facing inner groove208defined along the inner diameter of the baffle member170. Similarly the outer seal206can be disposed in a radially outwardly facing outer groove210defined along the outer diameter of the baffle member170in the peripheral rim region188. While a radial seal is shown at the outer region, alternatively or in addition an axial seal may be provided along the axial contact interface ring194.

While the baffle member170could be a stamped steel component, preferably and as illustrated, the baffle member170comprises a cast and/or machined member (and may be aluminum) to provide for the expanded ability to have several structural features as discussed above. By virtue of making the baffle member in this manner, heavy stamping of such baffles can be avoided.

Additionally, the baffle member170can be retained to the fixed scroll compressor body110. Specifically, as can be seen in the figures, a radially inward projecting annular flange214of the inner hub region184of the baffle member170is trapped axially between the stop plate212and the fixed scroll compressor body110. The stop plate212is mounted with bolts216to a fixed scroll compressor body210. The stop plate212includes an outer ledge218that projects radially over the inner hub172of the fixed scroll compressor body110. The stop plate ledge218serves as a stop and retainer for the baffle member170. In this manner, the stop plate212serves to retain the baffle member170to the fixed scroll compressor body110such that the baffle member170is carried thereby.

As shown, the stop plate212can be part of a check valve220. The check valve includes a moveable valve plate element222contained within a chamber defined in the outlet area of the fixed scroll compressor body within the inner hub172. The stop plate212thus closes off a check valve chamber224in which the moveable valve plate element222is located. Within the check valve chamber there is provided a cylindrical guide wall surface226that guides the movement of the check valve220along the central axis54. Recesses228are provided in the upper section of the guide wall226to allow for compressed refrigerant to pass through the check valve when the moveable valve plate element222is lifted off of the valve seat230. Openings232are provided in the stop plate212to facilitate passage of compressed gas from the scroll compressor into the high pressure chamber180. The check valve is operable to allow for one way directional flow such that when the scroll compressor is operating, compressed refrigerant is allowed to leave the scroll compressor bodies through the compression outlet126by virtue of the valve plate element222being driven off of its valve seat230. However, once the drive unit shuts down and the scroll compressor is no longer operating, high pressure contained within the high pressure chamber180forces the movable valve plate element222back upon the valve seat230. This closes off check valve220and thereby prevents backflow of compressed refrigerant back through the scroll compressor.

During operation, the scroll compressor assembly10is operable to receive low pressure refrigerant at the housing inlet port18and compress the refrigerant for delivery to the high pressure chamber180where it can be output through the housing outlet port20. As is shown, inFIGS. 1 and 4, a suction duct234is connected internally of the housing12to guide the lower pressure refrigerant from the inlet port18into housing and beneath the motor housing. This allows the low pressure refrigerant to flow through and across the motor and thereby cool and carry heat away from the motor which can be caused by operation of the motor. Low pressure refrigerant can then pass longitudinally through the motor housing and around through void spaces therein toward the top end where it can exit through a plurality of motor housing outlets240(seeFIG. 2) that are equally angularly spaced about the central axis54. The motor housing outlets240may be defined either in the motor housing48, the upper bearing member42or by a combination of the motor housing and upper bearing member (e.g. by gaps formed therebetween as shown inFIG. 2). Upon exiting the motor housing outlet240, the low pressure refrigerant enters an annular chamber242formed between the motor housing and the outer housing. From there, the low pressure refrigerant can pass through the upper bearing member through a pair of opposed outer peripheral through ports244that are defined by recesses on opposed sides of the upper bearing member42to create gaps between the bearing member42and housing12as shown inFIG. 3(or alternatively holes in bearing member42). The through ports244may be angularly spaced relative to the motor housing outlets240. Upon passing through the upper bearing member42, the low pressure refrigerant finally enters the intake area124of the scroll compressor bodies110,112. From the intake area124, the lower pressure refrigerant finally enters the scroll ribs114,118on opposite sides (one intake on each side of the fixed scroll compressor body) and is progressively compressed through chambers122to where it reaches it maximum compressed state at the compression outlet126where it subsequently passes through the check valve220and into the high pressure chamber180. From there, high pressure compressed refrigerant may then pass from the scroll compressor assembly10through the refrigerant housing outlet port20.

Referring toFIGS. 1-4, it is seen that a suction duct234is preferably employed to direct incoming fluid flow (e.g. refrigerant) through the housing inlet18. To provide for the inlet18, the housing includes an inlet opening310in which an inlet fitting312is provided that includes a connector such as threads314or other such connection means such as a barb or quick connect coupler, for example. The inlet fitting312is welded to the housing shell in engagement with the inlet opening310. The inlet opening310and the inlet fitting312are thereby provided for communicating the refrigerant into the housing.

Additionally, a suction screen316is provided to form a common bridge and thereby communicate refrigerant from the inlet18through the entrance opening and port318formed in the suction duct234. Substantially all (in other words—all or most) of the incoming refrigerant is thereby directed through the suction screen where metal shavings or other particulates can be screened out by an integral screen provided by the suction screen316. Once passing through the screen, refrigerant is then directed by the suction duct234to a location upstream and at the entrance of the motor housing.

Turning in greater detail to the suction duct234, and referring toFIGS. 5-10, it is seen that the suction duct comprises a stamped sheet steel metal body having a constant wall thickness with an outer generally rectangular and arcuate mounting flange320which surrounds a duct channel322that extends between a top end324and a bottom end326. The entrance opening and port318is formed through a channel bottom328proximate the top end324. This opening and port318provide means for communicating and receiving fluid from the inlet18via a suction screen flange316which is received through the outer compressor housing wall and into duct channel322of the suction duct234. The duct channel provides a fluid flow path to a drain port330proximate the bottom end326as shown in the figures. In this embodiment, the drain port330extends through the bottom end326and thereby provides a port for draining lubricant oil into the lubricant sump (see e.g.76inFIG. 1) and also to communicate substantially all of the refrigerant for compression to a location just upstream of the motor housing. Preferably, the drain port330is provided by at least one and typically two or more recessed grooves332that connect the duct channel322toward the lubricant sump. The recessed grooves332are formed into the rectangular mounting flange320and extends substantially vertically and axially to provide for axial and/or vertical flow as opposed to circumferential or radial flow.

With reference toFIGS. 5-11, the mounting flange320is generally rectangular and arcuate about an axis to surround the duct channel322and abuts the exterior surface of the motor housing. It further comprises fasteners sockets in the form of holes334proximate the corners of the mounting flange320such that fasteners336may be used to fasten and thereby secure the mounting flange320to the motor housing. Preferably, the suction duct is a metal stamping of sheet metal to provide the body and wall structure of the suction duct234as a unitary member. The rectangular and arcuate mounting flange and the duct channel can readily be stamped into the sheet metal to provide an elongated duct channel322and bottom grooves332as well as the fastener holes334. The entrance port318is also formed by stamping and punching out the generally circular disk from the sheet metal. Material stamp forming of the punched out area creates an annular opening flange338defining the entrance port318, which projects from the channel bottom328toward the mounting flange320. As shown, the annular opening flange338tapers as it extends radially inward and away from the channel bottom328so as to provide a tapered guide surface340that facilitates insertion and assembly of the suction screen flange316into engagement and received within the suction duct234.

Not only does the suction duct234direct refrigerant and substantially all of the refrigerant from the inlet18to a location upstream of the motor and to direct fluid flow through the motor, but it also acts as a gravitational drain preferably by being at the absolute gravitational bottom of the suction duct or proximate thereto so as to drain lubricant received in the suction duct into the lubricant sump76. This can be advantageous for several reasons. First, when it is desirable to fill the lubricant sump either at initial charting or otherwise, oil can readily be added through the inlet18which acts also as an oil fill port as oil will naturally drain through the suction duct and into the oil sump through the drain port330. The housing can thereby be free of a separate oil port. Additionally, the surfaces of the suction duct234and redirection of oil therein causes coalescing of oil lubricant mist which can then collect within the duct channel and drain through the drain port330back into the oil sump. Thus, direction of refrigerant as well as direction of lubricant oil is achieved with the suction duct.

Turning in greater detail to the suction screen member316with additional reference to a first embodiment shown inFIGS. 11-15, the suction screen member316generally includes a solid ring body with several regions including a mounting flange342that is adapted to mount the overall structure in the inlet fitting312; and a tubular and cylindrical extension344. The tubular extension supports a screen346along its inside. As shown, the mounting flange342and the tubular extension344are commonly and unitarily formed from relatively thin sheet metal material that has a constant wall thickness. The mounting flange342comprises a folded over metal section that includes inner and outer cylindrical rings348,350that are joined at an annular bend352that forms an upstream end of the suction screen member316. This makes the mounting flange342at least two layers thick of sheet metal. Connecting the mounting flange342and the tubular extension344is an annular neck354that may be conical in shape and reduces the diameter and thereby the perimeter from the mounting flange342to the tubular extension344. This also provides an annular seating surface356that axially abuts and seats against a corresponding annular seat358defined between larger and smaller diameter openings within the inlet fitting312.

The tubular extension344may be generally cylindrical and of a smaller diameter then the mounting flange342and may only be a single layer thick of sheet metal material. The screen346is arranged to screen fluid flow through the tubular extension344and thereby prevent the incursion of metal shavings, or other particulates into the scroll compressor.

In this embodiment, the screen346comprises a dome-shaped screen structure such as mesh material that projects away from a terminating end of the tubular extension344and covers the entire opening of the tubular extension344at the exit end to ensure that all refrigerant or other fluid (such as lubricant) entering the compressor housing is free of undesirable particulates such as metal shavings. As such, the screen346generally includes a dome portion360and also includes a generally cylindrical liner segment that lines the inside diameter of the tubular extension344and extends over the neck region and is crimped within the folded over metal section between the inner and outer crimped rings348,350of the mounting flange342. This secures and adequately seals the mesh material of the screen346with the sheet metal body of the mounting flange and tubular extension structure. As a result, the suction screen member may consist of as little as only two component parts including the sheet metal body and the mesh acting as a screen.

As shown inFIG. 11, the suction screen member316bridges the gap between the suction inlet fitting312and the internal suction duct234. As shown, the entrance port318of the suction duct234is aligned with the inlet port18formed by the inlet fitting312for the compressor housing. Preferably these openings are diametrically and concentrically aligned. Additionally, it is noted that a single part both provides for screening of fluid flow and also bridging the gap to ensure that substantially all of the fluid flow into the compressor housing does not bypass the suction duct234. Thus, the suction screen member not only acts as a screening function, but also a bridging function bridging the gap between the suction inlet fitting and the suction duct.

Recognizing that there can be tolerance issues and/or assembly inaccuracies that result in slight misalignments between the suction duct and the inlet fitting in their respective openings, different means are contemplated for accommodating misalignment. For example, in the present embodiment, the dome portion360provides a surface that helps to self locate during installation, as it can co-act with the tapered guide surface340on the suction duct234to guide insertion. Additionally, and considering that the tubular extension344is of a larger diameter than the dome portion360and/or liner segment362and is configured to be closely received into complete or almost complete circular engagement with the opening flange338of the suction duct234, axial slots364are formed partially into the tubular extension and extend from the terminating end thereof partially toward the mounting flange342to thereby provide some flexibility in the tubular extension structure. Specifically, the slots364allow for contraction and expansion of the terminating end portion of the tubular extension344so that misalignments can be accommodated while the tubular extension344is still closely received and engages the opening flange338of the suction duct234.

As shown in the alternative embodiment ofFIG. 16, an alternative means for accommodating misalignment is provided in the form of a thin sheet metal body sleeve (on the order of about 0.015 inch and typically less than 0.02 inch) to provide a solid metal tubular extension372that can flex to accommodate misalignment without necessarily requiring the slots. To assist further and to facilitate such metal flexure, preferably a chamfer374is provided on the terminating end of the solid metal tubular extension372to facilitate better insertion and deflection of the tubular extension372.

Another embodiment of a suction screen member380is illustrated inFIGS. 17-19. This embodiment also includes a ring body formed from metal such as sheet metal but in this embodiment is only a single layer thick along its length and without having a crimped section as in the first embodiment. The ring body includes an annular mounting flange382and a tubular extension384joined by an annular neck386that provides a seating surface similar to the first embodiment and thereby is installable in the same housing shown inFIGS. 1-4against the same seat of the inlet fitting (seeFIG. 11). In this embodiment a screen388of mesh material is also provided, but this embodiment includes a flat end disc390and a cylindrical liner392. At the corner therebetween a protective border frame394is provided in surrounding relation. The border frame394is of smaller size and perimeter than the tubular extension so as to better facilitate assembly and installation. A chamfer396may also be provided on the terminating edge of the tubular extension to provide means for accommodating misalignment during assembly. The cylindrical liner392is bonded to the inside wall surface of the tubular extension384such as by welding (e.g. fusing the materials together).