Abstract:
A scroll compressor including a hermetic housing with a motor-compressor unit disposed therein, including fixed and orbiting scrolls. The fixed scroll defines perpendicular axial and radial directions, and includes an outer wall having a suction inlet facing substantially in the radial direction. A baffle member is associated with the suction inlet of the fixed scroll, and in one embodiment, is attached to the fixed scroll with fasteners. The baffle member includes a first open end facing in the axial direction toward a suction port of the compressor housing, and a second open end facing in the radial direction in fluid flow alignment with the suction inlet of the fixed scroll. The baffle member directs a portion of the working fluid which enters the compressor housing substantially directly into the suction inlet of the fixed scroll to reduce turbulent flow of the working fluid within the compressor housing, improving the operating efficiency of the compressor.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is a continuation-in-part of U.S. patent application Ser. No. 11/120,127, entitled SUCTION BAFFLE FOR SCROLL COMPRESSORS, filed on May 2, 2005, the disclosure of which is expressly incorporated by reference herein. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to scroll machines, and in particular, to the manner in which a working fluid is drawn into the variable volume working pockets which are defined between the fixed and orbiting scrolls of a scroll compressor.  
         [0004]     2. Description of the Related Art  
         [0005]     Referring to  FIG. 1 , a scroll compressor  10  is shown, which includes main housing  12 , bottom cap  14  with base  16  secured to the lower end of housing  12 , and a separator plate  18  and top cap  20  each secured to the upper end of housing  12  by a welding, brazing, or other suitable operation to define an enclosed hermetic housing in which the motor-compressor unit  22  of compressor  10  is disposed. Motor-compressor unit  22  generally includes a first, fixed scroll  24 , a second, orbiting scroll  26 , crankcase  28 , drive shaft  30 , stator  32 , rotor  34 , and outboard bearing assembly  36 . Separator plate  18  is secured around its perimeter to the interior of housing  12 , such as by welding, and divides the interior of the housing  12  into a suction chamber  38  in fluid communication with suction port  40  in housing  12 , and discharge chamber  42  in fluid communication with discharge port  44  in top cap  20 .  
         [0006]     Fixed scroll  24  is secured to separator plate  18 , such as by a plurality of bolts, and includes outer wall  46  extending from base plate  48 , and an involute wrap  50  extending from base plate  48  and disposed inwardly of outer wall  46 . Fixed scroll  24  further includes a plurality of mount flanges  52  spaced radially about the end of outer wall  46  opposite base plate  48 , and a plurality of bolts secure mount flanges  52  to crankcase  28 . Crankcase  28  includes main bearing  54  in which the upper portion of drive shaft  30  is rotatably supported. Stator  32  is fixed within housing  12  by a plurality of bolts (not shown) which pass through outboard bearing assembly  36 , stator  32 , and into crankcase  28 . Drive shaft  30  is secured to rotor  34  in a suitable manner, and outboard bearing assembly  36  includes outboard bearing  56  which supports a lower end of drive shaft  30 . The upper portion of drive shaft  30  includes an eccentric end mounted within annular hub  58  extending downwardly from base plate  60  of orbiting scroll  26 . Orbiting scroll  26  additionally includes an involute wrap  62  extending upwardly from base plate  60  thereof, which is in meshing relationship with wrap  50  of fixed scroll  24 . Oldham coupling  64  is operatively coupled between orbiting scroll  26  and crankcase  28  to prevent rotation of orbiting scroll  24 , as is known.  
         [0007]     In operation, electrical energization of stator  32  rotatably drives rotor  34  and drive shaft  30  to move orbiting scroll  26  in an orbiting manner with respect to fixed scroll  24 . A working fluid at suction pressure is drawn from suction chamber  38  into a suction inlet  66  of fixed scroll  24 , and is compressed within the plurality of variable volume, working pockets which are defined between wraps  50  and  62  of fixed and orbiting scrolls  24  and  26 , respectively, as orbiting scroll  26  rotates in a known manner. The compressed working fluid is then discharged through discharge outlet  68  in base plate  48  of fixed scroll  24 , through discharge check valve assembly  70 , and into discharge chamber  42  at a discharge pressure.  
         [0008]     More specifically, working fluid at suction pressure enters suction chamber  38  via suction port  40  and initially impinges upon crankcase  28 . Thereafter, a portion of the working fluid flows downwardly within suction chamber  38 , as designated by arrow A in  FIG. 1 , and another portion of the working fluid flows upwardly within suction chamber  38 , as designated by arrow B in  FIG. 1 . Problematically, the portion of the working fluid which flows upwardly within suction chamber  38  along arrow B contacts housing  12 , separator plate  18 , and outer wall  46  of fixed scroll, which tends induces a spiraling, turbulent flow of the working fluid in the upper portion of suction chamber  38 , illustrated by arrows C in  FIG. 1 , before the working fluid is eventually drawn into suction inlet  66  of fixed scroll  24 .  
         [0009]     The turbulent flow of the working fluid within the upper portion of suction chamber  38  can potentially adversely effect the operating efficiency of compressor  10  by inhibiting uniform suction of working fluid into the suction inlet of the scrolls. Additionally, the working fluid also tends to become heated, for example by the discharge gas above separator plate  18 , if the working fluid circulates within the upper portion of the suction chamber before entering the suction inlet of the scrolls, which can also reduce the efficiency of the compressor.  
         [0010]     It is known to mount a baffle in a scroll compressor to the inner surface of the compressor housing over the suction inlet port. Problematically, however, these types of baffles are difficult to assemble after the motor compressor unit is installed within the compressor housing, and alternatively, when these types of baffles are attached to the interior of the compressor housing prior to installation of the motor compressor unit, same can impede mounting of the motor compressor unit within the compressor housing. Also, the connection between the baffle and the compressor housing may not be substantially rigid, and suction gas may be allowed to escape into the suction chamber as same travels between the suction baffle and the inlet of the scrolls.  
         [0011]     What is needed is a scroll compressor which is an improvement over the foregoing.  
       SUMMARY OF THE INVENTION  
       [0012]     The present invention provides a scroll compressor including a hermetic housing with a motor-compressor unit disposed therein, including fixed and orbiting scrolls. The fixed scroll defines perpendicular axial and radial directions, and includes an outer wall having a suction inlet facing substantially in the radial direction. A baffle member is associated with the suction inlet of the fixed scroll, and in one embodiment, is attached to the fixed scroll with fasteners. The baffle member includes a first open end facing in the axial direction toward a suction port of the compressor housing, and a second open end facing in the radial direction in fluid flow alignment with the suction inlet of the fixed scroll. The baffle member directs a portion of the working fluid which enters the compressor housing substantially directly into the suction inlet of the fixed scroll to reduce turbulent flow of the working fluid within the compressor housing, improving the operating efficiency of the compressor.  
         [0013]     In one form thereof, the present invention provides a compressor, including a housing having a suction port; a motor-compressor unit disposed within the housing, including a crankcase and a stator, rotor, and drive shaft assembly, the drive shaft rotatably supported by the crankcase, the crankcase including a wall directly facing, and in fluid communication with, the suction port; a first scroll member fixed with respect to the housing and defining perpendicular axial and radial directions, the first scroll member including a base plate; a first wrap extending from the base plate; and an outer wall having a suction inlet facing substantially in the radial direction, the suction inlet including a baffle member; and a second scroll member coupled to the drive shaft for orbital movement, the second scroll member including a second wrap intermeshed with the first wrap.  
         [0014]     In another form thereof, the present invention provides a compressor, including a housing having a suction port and a discharge port; a motor-compressor unit disposed within the housing, including a crankcase and a stator, rotor, and drive shaft assembly, the drive shaft rotatably supported by the crankcase; a first scroll member fixed with respect to the housing and defining perpendicular axial and radial directions and having a lower end with respect to the axial direction, the first scroll member including a base plate; a first wrap extending from the base plate; an outer wall having a suction inlet facing substantially in the radial direction; and a baffle member attached to the fixed scroll and including an open end facing substantially in the axial direction toward the suction port, the baffle member having a lower end which does not extend beyond the lower end of the base plate of the first scroll member; and a second scroll member coupled to the drive shaft for orbital movement, the second scroll member including a second wrap intermeshed with the first wrap.  
         [0015]     In a further form thereof, the present invention provides a compressor, including a housing having a suction port and a discharge port; a motor-compressor unit disposed within the housing and operable to receive a working fluid at a suction pressure from the suction port, compress the working fluid, and discharge the working fluid at a discharge pressure through the discharge port, the motor-compressor unit including a crankcase including at least one wall directly facing the suction port such that working fluid entering the suction port impinges directly on the crankcase wall; a stator, rotor, and drive shaft assembly, the drive shaft rotatably supported by the crankcase; a first scroll member fixed with respect to the housing and defining perpendicular axial and radial directions, the first scroll member including a base plate, a first wrap extending from the base plate, and an outer wall having a suction inlet facing substantially in the radial direction; a second scroll member coupled to the drive shaft for orbital movement, the second scroll member including a second wrap intermeshed with the first wrap; a baffle member attached to the first scroll and including a first end facing substantially in the axial direction toward the suction port and a second end facing substantially in the radial direction toward the suction inlet, whereby at least a portion of the working fluid which enters the suction port and impinges directly on the crankcase wall is directed by the baffle member into the suction inlet.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]     The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention itself will be better understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings, wherein:  
         [0017]      FIG. 1  is a vertical sectional view through a known scroll compressor, illustrating the flow of working fluid within the suction chamber of the compressor;  
         [0018]      FIG. 2  is a first perspective exploded view showing a fixed scroll and a baffle member according to the present invention;  
         [0019]      FIG. 3  is a second perspective exploded view of the fixed scroll and the baffle member of  FIG. 2 ;  
         [0020]      FIG. 4  is a vertical sectional view through the scroll compressor of  FIG. 1 , showing the fixed scroll and the baffle member of  FIGS. 2 and 3 , and illustrating the manner in which the baffle member directs working fluid into the suction inlet of the fixed scroll;  
         [0021]      FIG. 5  is a fragmentary view of a portion of the crankcase, showing the suction port in phantom; and  
         [0022]      FIG. 6  is a fragmentary perspective view of the upper portion of the compressor shown without the top cap and scroll members. 
     
    
       [0023]     Corresponding reference characters indicate corresponding parts throughout the several views. The exemplification set out herein illustrates one preferred embodiment of the invention, in one form, and such exemplification is not to be construed as limiting the scope of the invention any manner.  
       DETAILED DESCRIPTION  
       [0024]     Referring to  FIGS. 2-4 , baffle member  80  according to the present invention is shown, which is associated with suction inlet  66  of fixed scroll  24  of scroll compressor  10 . Except as described below, the components of scroll compressor  10  which are shown in  FIGS. 2-4  are substantially identical to the components of scroll compressor  10  which are shown in  FIG. 1 , and the same reference numerals will be used to indicate identical or substantially identical components therebetween. Although scroll compressor  10  is shown disposed vertically in  FIG. 4 , baffle member  80  of the present invention is equally applicable in scroll compressors which are disposed horizontally or in other orientations. Further details regarding scroll compressor  10  are disclosed in U.S. Patent Application Publication No. 2004/0047754, assigned to the assignee of the present invention, the disclosure of which is expressly incorporated herein by reference.  
         [0025]     Referring to  FIG. 2 , fixed scroll  24  defines perpendicular radial and axial directions. The radial direction is generally aligned along a line such as R 1 -R 1  of  FIG. 2  which, with reference to  FIG. 4 , is substantially perpendicular to the long axis of scroll compressor  10 . The axial direction is generally aligned along line A 1 -A 1  of  FIG. 2  which, with reference to  FIG. 4 , is substantially parallel to the long axis of scroll compressor  10 .  
         [0026]     Referring to  FIGS. 2 and 3 , baffle member  80  includes front wall  82 , curved top wall  84 , and a pair of opposing side walls  86 . Front wall  82  and side walls  86  together define a first open end  88  of baffle member  80  which, as shown in  FIGS. 2-4 , faces in the axial direction toward suction port  40  of scroll compressor  10  when baffle member  80  is secured to fixed scroll  24  in the manner described below. Top wall  84  and side walls  86  together define a second opening  90  of baffle member  80  which, as shown in  FIGS. 2-4 , faces in the radial direction toward suction inlet  66  of fixed scroll  24  when baffle member  80  is secured to fixed scroll  24  in the manner described below.  
         [0027]     Baffle member  80  may be made from metal, such as from stamped or formed sheet steel, or from cast materials. Alternatively, baffle member  80  may be made of a suitable substantially rigid plastic material, such as polyethylene, polystyrene, polypropylene, ABS, or polyether ether ketone (“PEEK”) by injection molding, for example. When baffle member  80  is made of a substantially non-heat conducting plastic material, baffle member  80  advantageously insulates the working fluid which passes through baffle member  80  from becoming heated by heat from the scrolls or from the discharge chamber  42 , thereby increasing the operating efficiency of compressor  10 .  
         [0028]     Top wall  84  of baffle member  80  includes a pair of apertures  92  through which fasteners  94  are inserted. Fasteners  94  in turn threadably engage respective holes  96  in base plate  48  of fixed scroll  24  to secure baffle member  80  to fixed scroll  24  with top wall  84  of baffle member  80  in abutment with base plate  48  of fixed scroll  24  and side walls  86  of baffle member  80  in abutment with sides  98  of outer wall  46  of fixed scroll  24 .  
         [0029]     Alternatively, baffle member  80  may be secured to base plate  48  of fixed scroll  24  by other fasteners such as rivets, for example, or may be secured to base plate  48  of fixed scroll  24  in a fastenerless manner, such as by welding or brazing. Each of these attachment methods advantageously rigidly secures baffle member  80  to base plate  48  of fixed scroll  24  to prevent baffle member  80  from generating vibrational sound during operation of the compressor. Baffle member  80  also may be secured to outer wall  46  of fixed scroll  24 , such as by welding, brazing, or with suitable fasteners. Further, baffle member  80  may be formed integrally with fixed scroll  24 .  
         [0030]     As may be seen in  FIGS. 2 and 4 , walls  82  and  86  of baffle member  80  define a lower end  87  of baffle member  80  and top wall  84  of baffle member  80  defines an upper end of baffle member  80  which, when baffle member  80  is attached to fixed scroll  24 , may not extend downwardly or upwardly beyond lowermost and uppermost ends of fixed scroll  24 , respectively. The lowermost end of fixed scroll  24  is defined by the tips of fixed scroll wrap  50  and/or the lowermost ends of mount flanges  52  of fixed scroll  24 , and the uppermost end of fixed scroll  24  is defined by the axial upper surface of base plate  48  of fixed scroll  24 . The lower and upper ends of baffle member  80  and fixed scroll  24  are defined with respect to the axial direction of compressor  10  and fixed scroll  24  and, alternatively stated, are the ends of baffle member  80  and fixed scroll  24  that are disposed most closely toward or away from crankcase  28  and the lower end of compressor  10 , respectively. In this manner, baffle member  80  does not project beyond the lowermost or uppermost ends of fixed scroll  24 , thereby reducing the potential for baffle member  80  to be bent or otherwise damaged by inadvertent contact during handling of fixed scroll  24  after attachment of baffle member  80  to fixed scroll  24  and prior to mounting fixed scroll  24  within compressor  10 .  
         [0031]     Alternatively, the lowermost end of baffle member  80  may, in other embodiments, extend downwardly beyond the lowermost end of fixed scroll  24 . As shown in  FIG. 4 , the upper end of baffle member  80 , defined by wall  84  thereof, is disposed at substantially the same axial level with respect to the location at which wrap  50  is joined to base plate  48  of fixed scroll  24 . However, depending on the axial height of the wrap  50  of fixed scroll  24 , the upper end of baffle member  80  may be positioned either above or below the end of wrap  50  which is joined to base plate  48  of fixed scroll  24 .  
         [0032]     With reference to  FIGS. 2-4 , when baffle member  80  is mounted to fixed scroll  24  in association with suction inlet  66  of fixed scroll  24  in the manner described above, first open end  88  of baffle member  80  faces in the axial direction toward suction port  40  of compressor  10 , and is disposed generally proximate suction port  40  yet spaced slightly away therefrom in the axial direction. Also, when baffle member  80  is mounted to fixed scroll  24  in association with suction inlet  66  of fixed scroll  24  in the manner described above, second open end  90  of baffle member  80  faces in the radial direction, and is in fluid flow alignment with suction inlet  66  of fixed scroll  24 .  
         [0033]     As shown in  FIGS. 5 and 6 , crankcase  28  includes a horizontal bearing surface  29  ( FIG. 6 ) upon which base plate  60  of orbiting scroll  26  is bearingly supported, and a plurality of leg members  31  disposed in spaced relation about the outer periphery of crankcase  28 . Fasteners (not shown) extend into the lower ends of leg members  31  to connect stator  32  to crankcase  28 . Crankcase  28  includes wall  33  defined between adjacent pairs of leg members  31  on either side of suction port  40 , which wall  31  directly faces, and is in fluid communications with, suction port  40 . Additionally, wall  33  of crankcase  28  further includes an impingement section  35  extending upwardly from wall  33  between leg members  31  which also directly faces, and is in fluid communication with, suction port  40 . Impingement section  35  extends axially upwardly between legs  31  a greater distance than bearing surface  29  and the remainder of wall  33  of crankcase  28 .  
         [0034]     Referring to  FIG. 4 , operation of baffle member  80  in scroll compressor  10  will now be described. When scroll compressor  10  is operating, working fluid at suction pressure enters suction chamber  38  via suction port  40  along the general direction of the arrows through suctions ports  40  in  FIGS. 4 and 5  and initially impinges upon crankcase  28 . In particular, working fluid at suction pressure enters suction port  40  and impinges on wall  33  and on impingement section  35  of crankcase  28  between an adjacent pair of leg members  31  of crankcase  28 . Impingement section  35  blocks working fluid from passing into the space between crankcase  28  and orbiting scroll  26 . As may be seen from  FIGS. 4-6 , leg members  31 , wall  33 , and impingement section  35  direct and channel the working fluid such that a portion of the working fluid flows downwardly within suction chamber  38 , as designated by arrow D in  FIGS. 4 and 5 , and another portion of the working fluid flows upwardly within suction chamber  38 , as designated by arrow E in  FIGS. 4 and 5 . Lubricant entrained within the working fluid is separated from the working when the working fluid impinges upon crankcase  28 , and the lubricant falls downwardly by gravity into an oil sump within the lower portion of compressor  10 .  
         [0035]     The portion of the working fluid which flows upwardly within suction chamber  38  in the direction of arrow E enters first open end  88  of baffle member  80  and is directed by front wall  82 , curved top wall  84 , and side walls  86  of baffle member  80  through second open end  90  of baffle member  80  and into suction inlet  66  of fixed scroll  24  along the direction of arrows F in  FIG. 4 , and thence into the working pockets which are defined between wraps  50  and  62  of fixed and orbiting scrolls  24  and  26 , respectively. Thereafter, the working fluid is compressed within working pockets in a known manner, and is discharged through discharge outlet  68  of fixed scroll  24  and discharge valve assembly  70  along arrow G of  FIG. 4  into discharge chamber  42  at discharge pressure.  
         [0036]     In the foregoing manner, baffle member  80  operates to direct a portion of the working fluid which enters housing  12  of scroll compressor  10  directly into suction inlet  66  of fixed scroll  24 , thereby reducing turbulence in the flow of the working fluid within the upper portion of suction chamber  38  to increase the operating efficiency of compressor  10 .  
         [0037]     While this invention has been described as having a preferred design, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.