Title:
Rocker compressor mechanism
Kind Code:
A1


Abstract:
A compressor assembly for compressing a vapor, including a compression mechanism having at least one piston reciprocatingly mounted therein and a motor operably coupled to the compression mechanism. A drive shaft is rotatively mounted in the motor. A rocker mechanism for converting rotational motion of the drive shaft into reciprocating motion of the piston is provided that includes a mounting plate, having an inclined surface, integrally formed with one end of the drive shaft. The rocker mechanism also includes means for linking the mounting plate and the piston so that when the drive shaft rotates, the piston reciprocates within the compression mechanism. The means for linking the mounting plate and the piston is operatively coupled to the mounting plate and is mounted directly to the piston. The means for linking the mounting plate and the piston may include a bearing, a flat plate, or a second plate having an inclined surface.



Inventors:
Kosco, John S. (Tecumseh, MI, US)
Robbins, Elizabeth A. (Adrian, MI, US)
Application Number:
11/152215
Publication Date:
01/05/2006
Filing Date:
06/14/2005
Primary Class:
Other Classes:
417/410.1
International Classes:
F04B27/08; F04B35/04
View Patent Images:
Related US Applications:



Primary Examiner:
LESLIE, MICHAEL S
Attorney, Agent or Firm:
FAEGRE DRINKER BIDDLE & REATH LLP (FORT WAYNE, IN, US)
Claims:
What is claimed is:

1. A compressor assembly for compressing a vapor, comprising: a compression mechanism and a motor operably coupled to said compression mechanism, said compression mechanism including at least one piston reciprocatingly mounted therein; a drive shaft mounted in said motor for rotation therewith; a support plate mounted to said motor, said drive shaft extending through said support plate; and a rocker mechanism for converting rotational motion of said drive shaft into reciprocating motion of said piston, said rocker mechanism comprising: a mounting plate integrally formed with one end of said drive shaft, said mounting plate having an inclined surface; and means for linking said mounting plate and said piston, whereby when said drive shaft rotates, said piston reciprocates within said compression mechanism, said means for linking said mounting plate and said piston operatively coupled to said mounting plate and mounted directly to said piston.

2. The compressor assembly of claim 1 wherein said means for linking said mounting plate and said piston further includes a bearing fixedly mounted to said mounting plate, and a linkage arm operatively coupling said bearing and said piston.

3. The compressor assembly of claim 2 wherein said bearing further includes an inner race and an outer race, and a plurality of ball bearings located between said inner and outer races, said outer race fixedly mounted to said mounting plate, and said inner race rotatably mounted within said outer race.

4. The compressor assembly of claim 1 wherein said means for linking said mounting plate and said piston further includes an actuating plate, said actuating plate having an inclined surface in operative contact with said mounting plate inclined surface.

5. The compressor assembly of claim 4 further including a rod, said piston mounted to one end of said rod, said actuating plate fixedly mounted to said rod, and said rod slidingly passing through said mounting plate into said drive shaft.

6. The compressor of claim 5 further including a second support plate, said rod supported for sliding motion by said support plate.

7. The compressor of claim 1 wherein said means for linking said mounting plate and said piston further includes a flat plate mounted in abutting relationship with said mounting plate inclined surface, and a linkage arm operatively coupling said flat plate and said piston.

8. The compressor assembly of claim 7 wherein said flat plate is secured to said mounting plate by a retaining clip, said retaining clip including a spherical end and a plurality of legs, said legs having protrusions thereon to engage said drive shaft.

9. The compressor assembly of claim 8 wherein said flat plate pivots about said spherical end of said retaining clip.

10. The compressor assembly of claim 7 further comprising a spring captured under compression between said piston and said linkage arm, said linkage arm biased into contact with said flat plate by said spring.

11. The compressor assembly of claim 1 wherein said mounting plate further includes a plurality of grooves formed in said inclined surface, said grooves distributing lubricating oil to said inclined surface.

12. A compressor assembly for compressing a vapor, comprising: a compression mechanism and a motor operably coupled to said compression mechanism, said compression mechanism including at least one piston reciprocatingly mounted therein; a drive shaft mounted in said motor for rotation therewith; a support plate mounted to said motor, said drive shaft extending through said support plate; and a rocker mechanism for converting rotational motion of said drive shaft into reciprocating motion of said piston, said rocker mechanism comprising: a mounting plate integrally formed with one end of said drive shaft, said mounting plate having an inclined surface; a bearing fixedly mounted to said mounting plate; and a linkage arm operatively coupling said bearing and said piston.

13. The compressor assembly of claim 12 wherein said bearing further includes an inner race and an outer race, and a plurality of ball bearings located between said inner and outer races, said outer race fixedly mounted to said mounting plate, and said inner race rotatably mounted within said outer race.

14. The compressor assembly of claim 13 wherein said linkage is pivotally mounted to said piston and said inner race of said bearing.

15. The compressor assembly of claim 12 wherein said supporting plate includes a cylindrical hub in which said drive shaft is rotatably supported.

16. The compressor assembly of claim 13 wherein said outer race is secured to said mounting plate by a plurality of fasteners.

17. The compressor assembly of claim 15 wherein said outer race rotates with said drive shaft about said inner race, said inclined surface facilitating reciprocation of said piston. A compressor assembly for compressing a vapor, comprising: a compression mechanism and a motor operably coupled to said compression mechanism, said compression mechanism including at least one piston reciprocatingly mounted therein; a drive shaft mounted in said motor for rotation therewith; a support plate mounted to said motor, said drive shaft extending through said support plate; and a rocker mechanism for converting rotational motion of said drive shaft into reciprocating motion of said piston, said rocker mechanism comprising: a mounting plate integrally formed with one end of said drive shaft, said mounting plate having an inclined surface; and an actuating plate, said actuating plate having an inclined surface in operative contact with said mounting plate inclined surface.

18. A compressor assembly for compressing a vapor, comprising: a compression mechanism and a motor operably coupled to said compression mechanism, said compression mechanism including at least one piston reciprocatingly mounted therein; a drive shaft mounted in said motor for rotation therewith; a support plate mounted to said motor, said drive shaft extending through said support plate; and a rocker mechanism for converting rotational motion of said drive shaft into reciprocating motion of said piston, said rocker mechanism comprising: a mounting plate integrally formed with one end of said drive shaft, said mounting plate having an inclined surface; a flat plate mounted in abutting relationship with said mounting plate inclined surface; and a linkage arm operatively coupling said flat plate and said piston.

19. The compressor assembly of claim 18 wherein said flat plate is secured to said mounting plate by a retaining clip, said retaining clip including a spherical end and a plurality of legs, said legs having protrusions thereon to engage said drive shaft.

20. The compressor assembly of claim 19 wherein said flat plate pivots about said spherical end of said retaining clip.

21. The compressor assembly of claim 18 wherein said flat plate further includes a-semispherical protrusion integrally formed with said flat plate, said linkage arm engaging said protrusion.

22. The compressor assembly of claim 18 further comprising a spring captured under compression between said piston and said linkage arm, said linkage arm biased into contact with said flat plate by said spring.

Description:

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a reciprocating piston compressor, and more particularly to a rocker mechanism for converting rotational motion of the rotor of a compressor motor into linear motion for reciprocating one or more pistons in the compression mechanism.

2. Description of the Related Art

Reciprocating piston compressors or pumps use reciprocation motion of a piston within a cylinder to compress fluids such as refrigerant. The compressors or pumps are typically provided with a source of power and a drive shaft. The source of power may be a drive motor having the drive shaft attached thereto such that the drive motor induces rotation of the shaft. The compression or pumping mechanism is operatively connected to the opposite end of the drive shaft.

In one example of a reciprocating piston compressor, a housing including a cylinder block and cylinder head is provided to encase the compression mechanism. The drive shaft is an input shaft which is rotatably mounted in the housing having a portion of the shaft extending outwardly from one end of the housing. The motor is also located outside of the housing and engages the external portion of the drive shaft. A mechanism is provided between the drive shaft and the reciprocating pistons to convert rotational movement of the drive shaft into linear motion of the pistons. The mechanism includes an inclined surface fixedly mounted to one end of the drive shaft for rotation therewith. A wobble plate is non-rotatably mounted on top of the inclined surface via a centrally located ball joint or roller bearing. Pistons are mounted to the wobble plate and are received in cylinders defined in the cylinder block. As the inclined surface rotates the wobble plate rocks about its central point causing the pistons to reciprocate within their cylinders to compress or pump fluid located in the cylinders.

A further example of a reciprocating piston compressor includes a housing in which the motor and compression mechanism are mounted. The drive shaft is fixedly mounted in the rotor of the motor for rotation therewith. The motor is mounted on top of a cylinder block having a cylinder head attached thereto. One cylinder is defined in the cylinder block to receive each piston. The drive shaft extends into the cylinder clock and has a cam portion integrally formed with the drive shaft at points along the shaft in alignment with the cylinders. The pistons are mounted on the cam portions and as the drive shaft is rotatably driven by the motor, the pistons reciprocate within the respective cylinders to compress or pump fluid located in the cylinders.

SUMMARY OF THE INVENTION

The present invention provides a reciprocating piston compressor having a rocker mechanism for converting rotational motion of the rotor of an electric motor into linear motion for reciprocating one or more pistons. The drive shaft of the reciprocating piston compressor is fixedly mounted in the rotor for rotation therewith. A mounting plate having an inclined surface is integrally formed at the upper end of the drive shaft. The inclined surface is operatively coupled to one or more pistons by a bearing having an inner and outer race, a second inclined plate, or a second flat plate.

The invention comprises, in one form thereof, a compressor assembly for compressing a vapor. The compressor assembly includes a compression mechanism and a motor operably coupled to the compression mechanism. The compression mechanism includes at least one piston reciprocatingly mounted therein. A drive shaft is mounted in the motor for rotation therewith and a support plate is mounted to the motor with the drive shaft extending through the support plate. A rocker mechanism for converting rotational motion of the drive shaft into reciprocating motion of the piston is also provided. The rocker mechanism includes a mounting plate, having an inclined surface, integrally formed with one end of the drive shaft and means for linking the mounting plate and the piston such that when the drive shaft rotates, the piston reciprocates within the compression mechanism. The means for linking the mounting plate and the piston is operatively coupled to the mounting plate and is mounted directly to the piston.

The invention comprises, in another form thereof, a compressor assembly for compressing a vapor that includes a compression mechanism and a motor operably coupled to the compression mechanism. The compression mechanism includes at least one piston reciprocatingly mounted therein. A drive shaft is mounted in the motor for rotation therewith. A support plate is mounted to the motor with the drive shaft extending through the support plate. Also provided is a rocker mechanism for converting rotational motion of the drive shaft into reciprocating motion of the piston. The rocker mechanism includes a mounting plate integrally formed with one end of the drive shaft, the mounting plate having an inclined surface, a bearing fixedly mounted to the mounting plate, and a linkage arm operatively coupling the bearing and the piston.

The invention comprises, in a further form thereof, a compressor assembly for compressing a vapor. The compressor assembly includes a compression mechanism and a motor operably coupled to the compression mechanism. The compression mechanism includes at least one piston reciprocatingly mounted therein. A drive shaft is mounted in the motor for rotation therewith and a support plate is mounted to the motor with the drive shaft extending through the support plate. A rocker mechanism for converting rotational motion of the drive shaft into reciprocating motion of the piston is also provided. The rocker mechanism includes a mounting plate integrally formed with one end of the drive shaft, the mounting plate having an inclined surface, and an actuating plate. The actuating plate has an inclined surface in operative contact with the mounting plate inclined surface.

The invention comprises, in one form thereof, a compressor assembly for compressing a vapor. The compressor assembly includes a compression mechanism and a motor operably coupled to the compression mechanism. The compression mechanism includes at least one piston reciprocatingly mounted therein. A drive shaft is mounted in the motor for rotation therewith and a support plate mounted to the motor with the drive shaft extending through the support plate. A rocker mechanism for converting rotational motion of the drive shaft into reciprocating motion of the piston is provided and includes a mounting plate integrally formed with one end of the drive shaft, the mounting plate having an inclined surface. The rocker mechanism further includes a flat plate mounted in abutting relationship with the mounting plate inclined surface, and a linkage arm operatively coupling the flat plate and the piston.

One aspect of the present invention is the in at least one embodiment, the wobble plate of the prior art is eliminated. This may be particularly advantageous in the production of the compressor, reducing the number of parts and thus the cost of manufacturing.

Another advantage is of the present invention is that the pistons of the reciprocating piston compressor are mounted directly to means for linking the mounting plate and the piston, the means including a bearing, flat plate, or inclined plate. The use of a ball joint or roller bearing to mount the bearing, flat plate, or inclined plate of the present invention has been eliminated.

BRIEF DESCRIPTION OF THE DRAWINGS

The above mentioned and other features and objects 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 embodiments of the invention taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a sectional view of a reciprocating piston compressor in accordance with a first embodiment of the present invention showing a first position of the compression mechanism.

FIG. 2 is a sectional view of the compressor of FIG. 1 showing a second position of the compression mechanism.

FIG. 3 is a sectional view of a reciprocating piston compressor in accordance with a second embodiment of the present invention showing a first position of the compression mechanism.

FIG. 4 is a sectional view of the compressor of FIG. 3 showing a second position of the compression mechanism.

FIG. 5 is a sectional view of a reciprocating piston compressor in accordance with a third embodiment of the present invention showing a first position of the compression mechanism.

FIG. 6 is a sectional view of the compressor of FIG. 5 showing a second position of the compression mechanism.

FIG. 7 is an exploded sectional view of the assembly of the rocker mechanism of the compressor of FIG. 5.

FIG. 8 is a top view of the mounting plate of the drive shaft of FIG. 7 taken along line 8-8.

Corresponding reference characters indicate corresponding parts throughout the several views. Although the exemplification set out herein illustrates embodiments of the invention, in several forms, the embodiments disclosed below are not intended to be exhaustive or to be construed as limiting the scope of the invention to the precise forms disclosed.

DETAILED DESCRIPTION

In general, a reciprocating piston compressor is one in which the linear, reciprocating motion of one or more pistons within a cylinder compresses a working fluid such as a refrigerant from a low pressure to a higher pressure. Reciprocating piston compressors may be used in any suitable refrigeration or air-conditioning system (not shown).

The general structure and operation of a reciprocating piston compressor is discussed with reference to the first embodiment of reciprocating piston compressor 20, however, it is understood that the general structure and operation is the same for all embodiments discussed herein. Referring to FIGS. 1 and 2, reciprocating piston compressor 20 is a hermetic compressor assembly including housing 22 having main body portion 23 to which top end cap 24 and bottom end cap 26 are secured. End caps 24 and 26 are fixedly secured to housing main body portion 23 by any suitable method including welding, brazing, or the like so as to create a hermetically sealed environment within housing 22. Annular mount 28 is affixed to the lower surface of bottom end cap 26 by any suitable method to support compressor 20 in a substantially horizontal orientation.

Reciprocating piston compressor 20 is provided with drive motor 30 which includes stator 32 having windings 34, and rotor 36. Stator 32 is positioned in surrounding relationship of rotor 36 and is interference fitted within housing 22. Electrical current from an external power source (not shown) is directed through stator windings 34 via a terminal cluster (not shown) to electromagnetically induce rotation of rotor 36. Drive shaft 38 extends longitudinally through central aperture 40 in rotor 36 and is operatively connected to compression mechanism 42 in a manner which will be described further below.

Compression mechanism 42 is mounted above motor 30 and includes cylinder block 44 which is interference fitted within main body portion 23 of housing 22. At least one cylinder 46 is bored into cylinder block 44 with one piston 48 being reciprocatively positioned in each cylinder 46. In this embodiment, drive shaft 38 is operatively coupled to a pair of pistons 48′ and 48″ such that as drive shaft 38 is caused to rotate by rotation of rotor 36, refrigerant is drawn into cylinders 46 where it is compressed before being discharged to the refrigeration system, for example.

During compressor operation, refrigerant at suction pressure is drawn into housing 22 through an inlet (not shown). Compressor 20 is a low-side compressor with drive motor 30 being in a low pressure and low temperature environment. Alternatively, compressor 20 may also be a high side compressor with the motor being located in a high pressure and high temperature environment. Referring to FIG. 1, the suction pressure refrigerant is directed toward cylinders 46 and is drawn into cavity 50 defined in one cylinder 46 when piston 48′ is on a downward stroke. With cavity 50 filled with suction pressure refrigerant (FIG. 2), piston 48′ begins its upward stroke, reducing the volume of cavity 50 and compressing the refrigerant located therein. The compressed refrigerant has a high, discharge pressure as piston 48′ completes the upward stroke. The discharge pressure is great enough to overcome the biasing force of discharge valve 52 allowing the discharge pressure refrigerant gas to pass through discharge outlet 54 into cylinder head 56 mounted to cylinder block 44. The discharge pressure refrigerant then exits compressor 20 and flows into the refrigeration system.

The second piston 48″ is 180 degrees out of phase from the first piston 48′ such that as piston 48′ is compressing refrigerant in cavity 50, piston 48″ is on a downward stroke drawing suction pressure refrigerant into cavity 58 defined in cylinder 46. Once cavity 58 is filled with suction pressure refrigerant, piston 48″ begins an upward stroke, compressing the refrigerant to a higher, discharge pressure. The discharge pressure is great enough to overcome the biasing force of discharge valve 52 operatively associated with discharge outlet 54, thus allowing the discharge pressure refrigerant to exit compressor 20 and flow into the refrigeration system.

Drive shaft 38 is operatively connected to compression mechanism 42 by rocker mechanism 60 which converts rotational motion of drive shaft 38 into linear, reciprocating motion of pistons 48. Rocker mechanism 60 includes mounting plate 62 integrally formed at the end of drive shaft 38. Mounting plate 62 includes first height 63 and second height 65 with the first height 63 being greater than the second height 65 to define inclined surface 64 on which bearing 66 of rocker mechanism 60 is fixedly mounted.

Annular supporting plate 68 is mounted above drive motor 30 by bolts 70. A first nut 72 threadedly engages each bolt 70 to support supporting plate 68. A second nut 74 is threaded onto each bolt 70 to secure the position of supporting plate 68. The height of supporting plate 68 may be adjusted as necessary by raising or lowering first nuts 72 along bolts 70. Integrally formed in supporting plate 68 is hub 76 through which drive shaft 38 extends and is rotatably supported by bearing 78. A second bearing 80 is located between lower surface 82 of mounting plate 62 and upper surface 84 of supporting plate 68.

Bearing 66 is a ball bearing including inner race 86 and outer race 88. A plurality of ball bearings 90 are located between inner and outer races 86 and 88 being seated in grooves 92 and 94 respectively formed in the races. Outer race 88 is fixedly secured to mounting plate 62 by a plurality of fasteners 96 such that outer race 88 rotates with drive shaft 38. Inner race 86 is secured to pistons 48 by linkage arms 98. Linkage arms 98 fix the position of inner race 86 relative to outer race 88 such that inner race 86 does not rotate.

The diameter of bearing 66 is determined by the spacing between first and second pistons 48′ and 48″ with the diameter of inner race 86 being substantially equal to the distance between the centers of the pistons. The length of the piston stroke is defined by the degree of incline of surface 64. With outer race 88 located about the outer periphery of mounting plate 68, the stroke of pistons 48′ and 48″ is at its greatest length such that the greater the degree of incline, the longer the stroke of the pistons.

During operation of compressor 20, drive shaft 38 rotates causing mounting plate 62 and thus outer race 88 of bearing 66 to rotate. Referring to FIG. 1, as mounting plate 62 rotates, the portion of mounting plate 62 having first height 63 forces piston 48′ to the top end of the upward stroke. Simultaneously, piston 48″ is aligned with the portion of mounting plate 62 having second height 65 and bottoms out at the end of its downward stroke. As mounting plate 62 continues to rotate pistons 48′ and 48″ reciprocate within cylinders 46 to a position shown in FIG. 2 wherein piston 48′ is aligned with the portion of mounting plate 62 having second height 65 and at the end of its downward stroke and piston 48″ is aligned with the portion of mounting plate 62 having first height 63 and at the end of its upward stroke.

Also during compressor operation, oil from oil sump 100 defined by the lower end of housing main body portion 23 and bottom end cap 26 is drawn through bore 102 formed in drive shaft 38 to lubricate inclined surface 64. The lubricating oil is also supplied to the surfaces of bearings 78 and 80 through radial passages (not shown) in drive shaft 38.

Referring to FIGS. 3 and 4, a second embodiment of a reciprocating compressor is illustrated. Reciprocating compressor 104 is a single piston compressor having piston 48 slidingly mounted in cylinder 46. Compressor 104 operates in a manner similar to that described above with regards to compressor 20. Suction pressure refrigerant is drawn into cylinder 46 when piston 48 is on the downward stroke. When piston 48 returns to its upward position, the suction pressure refrigerant is compressed to a higher, discharge pressure before exiting compressor 104 into a refrigeration system, for example.

In this embodiment, drive shaft 38 is operatively coupled to compression mechanism 105 by rocker mechanism 106 which converts rotational motion of drive shaft 38 into linear, reciprocating motion of piston 48. Rocker mechanism 106 includes mounting plate 108 and actuating plate 110. Mounting plate 108 has a first height 112 and a second height 114 with the first height being larger than the second height to define inclined surface 116. Actuating plate 110 also includes a first height 118 and a second height 120 with the first height being larger than the second height to define inclined surface 122. Mounting plate 108 is integrally formed at the end of drive shaft 38 for rotation therewith. Piston 48 has rod 124 secured to the lower end thereof. Actuating plate 110 is a non-rotating plate which is fixedly mounted to rod 124 by any suitable method including welding, brazing, or the like, thus actuating plate 110 moves linearly as mounting plate 108 rotates.

A first annular supporting plate 126 is located above motor 30 being supported on bolts 128 engaging motor 30 by first and second nuts 130 and 132. As discussed above, the location of supporting plate 126 is adjustable by moving nuts 130 and 132 along the length of bolts 128. A second annular plate 134 is mounted on bolts 128 in a position above rocker mechanism 106 by first and second nuts 136 and 138.

First annular supporting plate 126 is provided with opening 140 in which drive shaft 38 is rotatably supported by bearing 142. Bearing 144 is positioned between lower surface 146 of mounting plate 108 and upper surface 148 of first annular supporting plate 126 to rotatably support mounting plate 108. Bearing 142 is provided with protrusions 150 which lock the bearing in place between drive shaft 38 and first annular supporting plate 126. Second annular supporting plate 134 is provided with opening 152 through which rod 124 passes. Second annular supporting plate 134 is provided to support rod 124 as piston 48 reciprocates within cylinder 46.

Rod 124 passes through actuating plate 110 and is slidingly received in central cavity 154 passing through mounting plate 108 and into drive shaft 38. Central passageway 156 is located in rod 124 and aligns with bore 102. As drive shaft 38 rotates and oil is drawn upwardly along bore 102, the oil enters cavity 154 and central passageway 156 to provide lubrication to interfacing inclined surfaces 116 and 122 as well as between rod 124 and the inner surface of central cavity 154. As in the previous embodiment, oil is also provided to the surfaces of bearing 142 and 144 through radial passages (not shown) in drive shaft 38.

During operation of compressor 104, drive shaft 38 rotates causing mounting plate 108 to rotate. Referring to FIG. 3, in the first position, piston 48 is at the bottom end of cylinder 46 and inclined surfaces 116 and 122 are engaged. As mounting plate 108 rotates to a second position shown in FIG. 4, the portion of mounting plate 108 having first height 112 aligns with the portion of actuating plate 110 having first height 118, forcing piston 48 to the top end of the upward stroke and compressing refrigerant in cylinder 46. Rod 124 slides upwardly in central cavity 154 pulling oil from bore 102 along the inner surface of central cavity 154 to lubricate the cavity.

Referring to FIGS. 5 and 6, a third embodiment of a reciprocating piston compressor is shown. Reciprocating piston compressor 158 is a two piston compressor similar to compressor 20 of the first embodiment. Drive shaft 38 is operatively coupled to compression mechanism 159 by rocker mechanism 160 which converts the rotation motion of drive shaft 38 into linear motion of pistons 48′ and 48″. Rocker mechanism 160 includes mounting plate 162 having first height 164 and second height 166 with first height 164 being greater than second height 166 to define inclined surface 168. Drive shaft 38 passes through annular supporting plate 68 which is mounted within housing 22 above motor 30 in the same manner as described above. Bearings 78 and 80 are positioned between drive shaft 38, supporting plate 68, and mounting plate 162 to rotatably support drive shaft 38 and thus mounting plate 162.

Compression mechanism 159 is provided with cylinder block 170 in which cylinders 46 are formed to receive pistons 48′ and 48″. Cylinder head 172 is mounted to the upper surface of cylinder block 170 having discharge valves 174 mounted therein. Discharge valves 174 include valve plates 176 which are biased by springs 178 into a closed position over cylinders 46. One end of springs 178 is located in cavities 180 formed in cylinder head 172 while the opposite end of springs 178 are in engagement with upper surface 182 of valve plates 176. Valve passage 184 is formed in cylinder block 170 and has a diameter slightly larger than the diameter of cylinders 46 so that refrigerant cannot leak past valve plates 176. Discharge passages 186 are also formed in cylinder block 170 to provide passages for compressed discharge pressure refrigerant into the refrigeration system.

Rocker mechanism 160 further includes flat plate 188 which is non-rotatably mounted in abutting relationship to inclined surface 168 of mounting plate 162. Referring to FIGS. 5, 6, and 7, retaining clip 190 is used to secure flat plate 188 to mounting plate 162. Retaining clip 190 includes spherical end 192 and at least two legs 194 having protrusions 196 located at the end thereof for locking clip into place. Retaining clip 190 may be provided with any suitable number of legs 194 required to secure flat plate 188 in an assembled position with mounting plate 162. Located centrally in flat plate 188 is concave seat 198 in which spherical end 192 of clip 190 is seated. Retaining clip 190 is formed of a semi-rigid plastic material, for example, having resilient properties that allow legs 194 to move inwardly as retaining clip 190 is installed. Legs 194 pass through passage 200 in flat plate 188 and through a portion of bore 102 in drive shaft 38 into cutout portion 202 in drive shaft 38. Once protrusions 196 reach cutout portion 202, legs 194 return to their initial position and protrusions 196 engage surface 204 of cutout portion 202 to lock flat plate 188 against mounting plate 162.

Integrally formed on upper surface 190 of flat plate 188 is a protrusion 206 having a semispherical cross-section. Protrusion 206 is located about the periphery of flat plate 188 and has a diameter equal to the distance between the centers of pistons 48′ and 48″. Linkage arms 208 extend between protrusion 206 and pistons 48′ and 48″ to operatively connect drive shaft 38 to compression mechanism 159. One end of linkage arms 208 are provided with convex shaped cavity 210 into which protrusion 206 is seated. The opposite end of linkage arms 208 include spherical ends 212 which are received in pistons 48′ and 48″. Springs 213 are located between cylinder block 170 and surface 209 of linkage arms 208 to bias arms 208 into contact with protrusions 206, particularly during compressor startup.

During operation of compressor 158, drive shaft 38 rotates causing mounting plate 162 to rotate. Referring to FIG. 5, as mounting plate 162 rotates, the portion of mounting plate 62 having first height 164 forces piston 48′ to the top end of the upward stroke. This compresses refrigerant in cylinder 46 to a higher discharge pressure which is great enough to overcome the biasing force of spring 178, moving valve plate 176 from its seated position and allowing the refrigerant to exit compressor 158. Simultaneously, piston 48″ is aligned with the portion of mounting plate 162 having second height 166 and bottoms out at the end of its downward stroke. As mounting plate 162 continues to rotate, flat plate 188 rides along inclined surface 168, pivoting about spherical end 192 of retaining clip 190. Pistons 48′ and 48″ reciprocate within cylinders 46 to a position shown in FIG. 6 wherein piston 48′ is aligned with the portion of mounting plate 162 having second height 166 and at the end of its downward stroke and piston 48″ is aligned with the portion of mounting plate 162 having first height 164 and at the end of its upward stroke.

Also during compressor operation, as with previous embodiments, oil from oil sump 100 defined by the lower end of housing main body portion 23 and bottom end cap 26 is drawn through bore 102 formed in drive shaft 38 to lubricate inclined surface 168. As shown in FIG. 8, inclined surface 168 is provided with curved grooves 214 which direct the lubricating oil toward the outer periphery of mounting plate 162 to provide lubricating oil to the interfacing surfaces between mounting plate 162 and flat plate 188. The lubricating oil is also supplied to the surfaces of bearings 78 and 80 through radial passages (not shown) in drive shaft 38.

While this invention has been described as having an exemplary design, the present invention may 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.