US20060153705A1

US20060153705A1 - Drive shaft for compressor

Info

Publication number: US20060153705A1
Application number: US11/258,584
Authority: US
Inventors: W. Horton; Robert Mowatt; Daniel Hadesh
Original assignee: Tecumseh Products Co
Current assignee: Tecumseh Products Co
Priority date: 2004-11-10
Filing date: 2005-10-25
Publication date: 2006-07-13
Also published as: CA2525814A1

Abstract

A compressor assembly that includes a driveshaft and at least one eccentric press-fit to the shaft. In one embodiment, the driveshaft includes an opening at a first end and the eccentric includes a linking rod press-fit into the opening. During assembly, the first end of the shaft is inserted through an opening in a rotor and the eccentric is then press-fit to the first end. This arrangement allows the opening in the rotor to closely receive the driveshaft and allows the eccentric to be assembled to the compressor without passing the eccentric through the rotor opening. In use, the eccentric is operably engaged with a compressor mechanism such as, for example, a rotary compression mechanism, a reciprocating piston mechanism, or an orbiting scroll mechanism. In one embodiment, a second eccentric is press-fit to a second end of the driveshaft and is operably engaged with a second compressor mechanism.

Description

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Patent Application Ser. No. 60/626,787, entitled DRIVE SHAFT FOR COMPRESSOR, filed on Nov. 10, 2004, the entire disclosure of which is hereby expressly incorporated by reference herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention
The present invention relates generally to hermetic compressor assemblies having two compressor mechanisms driven by a single motor and, more particularly, to hermetic compressor assemblies having an improved drive shaft operably coupling the motor to the two compressor mechanisms.
2. Description of the Related Art
Compressor assemblies having two compressor mechanisms operably coupled to a single motor by a drive shaft are known. In many such assemblies, the drive shaft includes two integral eccentric portions defined at one end of the shaft. These eccentric portions are often machined into, or integrally molded with, the shaft such that they are unitary with the shaft. The motor includes a rotating rotor which defines a central bore extending through the rotor along a rotational axis. The end of the drive shaft opposite the eccentric portions extends into the bore and is affixed to the rotor for rotation therewith. Each of the integral eccentric portions operably engages one of the two compressor mechanisms, thereby mounting both of the two compressor mechanisms at one end of the drive shaft and adjacent one end of the motor.
Still, other dual mechanism compressor assemblies are known in which the unitary eccentric portions are defined at opposite ends of the drive shaft. In such assemblies, the two compressor mechanisms are operably mounted about the eccentric portions at opposite ends of the shaft and are thereby positioned adjacent opposite ends of the motor. Such an arrangement may be used to improve the balance of the compressor assembly, which may reduce vibration and noise produced by the compressor. However, oftentimes the eccentric portions define a larger cross-section than that of the drive shaft and cannot fit through the bore of the rotor. Consequently, it is difficult to assemble such a compressor using a one-piece shaft. Instead, these compressors require a two-piece drive shaft that is joined inside the rotor. However, the two-piece drive shaft design may be less rigid than the one-piece design, thereby causing the shaft to bend or deflect. Deflection of the shaft may cause the misalignment of the bearings, which ultimately may result in leaks and housing deformation.
Due to the problems associated with a drive shaft having unitary eccentric portions, a need remains for a hermetic compressor assembly having two compressor mechanisms operably engaged to opposite ends of a drive shaft without the use of eccentric portions unitarily defined in the drive shaft.

SUMMARY OF THE INVENTION

The present invention provides a compressor assembly that includes a driveshaft and at least one eccentric press-fit to the shaft. In one embodiment, the driveshaft includes an opening at a first end and the eccentric includes a linking rod press-fit into the opening. During assembly, the first end of the shaft is inserted through an opening in a rotor and the eccentric is then press-fit to the first end. This arrangement allows the opening in the rotor to closely receive the driveshaft and allows the eccentric to be assembled to the compressor without passing the eccentric through the rotor opening. In use, the eccentric is operably engaged with a compressor mechanism such as, for example, a rotary compression mechanism, a reciprocating piston mechanism, or an orbiting scroll mechanism. In one embodiment, a second eccentric is press-fit to a second end of the driveshaft and is operably engaged with a second compressor mechanism.
Owing to the press-fit relationship described above, in one embodiment, a set screw, fastener, pin, or welding process is not required to maintain the relative position of the eccentric and the driveshaft, as required by previous compressors. Advantageously, the time and cost to machine recesses for receiving the fasteners, pins or set screws can be eliminated. Additionally, in previous compressors, these recesses may wear or fret over time allowing the fasteners, pins, or set screws to come loose.
In one form, a compressor comprises a motor including a rotor, a driveshaft operably engaged with the rotor, the driveshaft including a first end extending from the rotor; and a first eccentric press-fit to the first end of the driveshaft.
In one form, a compressor comprises a motor, a driveshaft operably engaged with the motor, and a first eccentric, wherein one of the driveshaft and the first eccentric includes a first opening, and wherein the other of the driveshaft and the first eccentric is press-fit into the opening.
In one form, a method of assembling a compressor comprises the steps of inserting a first end of a driveshaft through an opening in a rotor, securing the rotor to the driveshaft, and press-fitting a first eccentric to the first end of the driveshaft.

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 dual mechanism hermetic compressor assembly according to the present invention;
FIG. 2 is a sectional view of the compressor assembly of FIG. 1 taken along lines 2-2;
FIG. 3 is an inner end perspective view of the crankcase/shaft assembly of the compressor assembly of FIG. 1;
FIG. 4 is an outside end view of the compressor mechanism of the compressor assembly of FIG. 1;
FIG. 5 is a perspective view of the shaft roller assembly of the compressor assembly of FIG. 1;
FIG. 6 is a perspective view of the inner roller of the compressor assembly of FIG. 1;
FIG. 7 is a perspective view of the shaft of the compressor assembly of FIG. 1;
FIG. 8 is a perspective view of a shaft according to another embodiment of the present invention;
FIG. 9 is a perspective view of a shaft/eccentric/piston assembly according to the embodiment of FIG. 8; and
FIG. 10 is a sectional view of compressor assembly with the assembly in FIG. 9.
Corresponding reference characters indicate corresponding parts throughout the several views. Although the exemplifications set out herein illustrate 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.

DESCRIPTION OF THE PRESENT INVENTION

Referring first to FIG. 1, compressor assembly 10 generally includes first compressor mechanism 14, second compressor mechanism 16 and motor assembly 18, all of which are disposed within interior volume 13 of housing 12. Housing 12 includes first and second end members 12 a, 12 b and cylindrical main member 12 c. Housing members 12 a, 12 b, 12 c are hermetically sealed to one another to define interior volume 13.
Still referring to FIG. 1, motor assembly 18 defines first end 26 and opposite second end 28 and includes rotor 20, stator 22 and stator windings 24. Motor assembly 18 is connected to a power source (not shown) which drives the rotation of rotor 20 about rotational axis A-A. Elongate drive shaft 30 extends through motor assembly 18 and operably connects first and second compressor mechanisms 14, 16 to motor assembly 18. Drive shaft 30 extends through a central bore in rotor 20 along rotational axis A-A and is rotatably secured to rotor 20 for rotation therewith about axis A-A. Shaft 30 may be secured to rotor 20 using conventional shrink-fit methods. One such method includes thermally expanding rotor 20, inserting shaft 30 through the central bore of thermally expanded rotor 20, and allowing rotor 20 to cool and, thus, shrink around shaft 30 to secure shaft 30 within rotor 20.
As illustrated in FIG. 1, drive shaft 30 is integrally formed as a single unit and defines first end portion 32, elongate central portion 34 and second end portion 36. First and second end portions 32, 36 of shaft 30 protrude from respective first and second ends 26, 28 of motor assembly 18 and operably engage first and second compressor mechanisms 14, 16, respectively, thereby positioning first and second compressor mechanisms 14, 16 proximate opposite ends of motor assembly 18. The positioning of first and second compressor mechanisms 14, 16 proximate opposite ends of motor assembly 18 provides improved balance in comparison to an assembly wherein one or more compressors are positioned proximate a single end of the motor. This improved balance may result in lower vibration and, ultimately, lower noise. The configuration of first and second end portions 34, 36 and their engagement with first and second compressor mechanisms 14, 16 is described in further detail below.
Turning to FIGS. 1 and 2, first and second compressor mechanisms 14, 16 are identical rotary-type mechanisms and each generally includes crankcase 38, annular cylinder block 40, top member 42, and roller assembly 43. Cylinder block 40 is mounted between crankcase 38 and top member 42. Top member 42, cylinder block 40 and crankcase 38 are secured to one another by fasteners (not shown) which extend through fastener-receiving holes 42 a, 40 a, 38 a of top member 42, cylinder block 40, and crankcase 38, respectively. Cylinder block 40 defines an inside wall which cooperates with crankcase 38 and top member 42 to form compression chamber 52 in which a compressible fluid, such as a refrigerant, may be compressed.
As shown in FIGS. 1 and 2, roller assembly 43 is disposed within compression chamber 52 and includes eccentric inner roller 44 and main roller 48 rotatably mounted about eccentric inner roller 44. Inner roller 44 is operably coupled to drive shaft 30, the rotation of which causes roller assembly 43 to orbit within compression chamber 52. The engagement between drive shaft 30 and inner roller 44 is described in further detail below. Needle roller bearings (not shown) may be mounted between inner roller 44 and main roller 48 to facilitate the rotation of main roller 48 about inner roller 44. Main roller 48 defines a cylindrical outer surface which travels along and sealingly engages the inside wall of cylinder block 40 to give compression chamber 52 an evolving crescent shape. Sliding vane 50 reciprocates within slot 51 defined in cylinder block 40 and engages main roller 48.
Referring to FIG. 1, crankcase 38 of each of first and second mechanisms 14, 16 is mounted on respective first and second ends 26, 28 of motor assembly 18, thereby securing first and second compressor mechanisms 14, 16 to opposite ends of motor assembly 18. Crankcase 38 may be mounted to motor assembly 18 in any conventional manner. One such manner involves inserting bolts (not shown) through holes 39 (FIGS. 2-4), which extend through legs 41 of crankcase 38, and engaging the bolts to threaded holes (not shown) in stator 22.
As illustrated in FIGS. 1 and 3-4, crankcase 38 defines a substantially cylindrical perimetrical sidewall 45 that firmly and sealingly bears against main housing member 12 c. The firm engagement between the sidewall of crankcase 38 and main housing member may be achieved by conventional shrink-fit methods. As a result of the sealed engagement between crankcase 38 and housing 12, the crankcases 38 of first and second compression mechanisms 14, 16 cooperate with one another to sealingly divide interior plenum 13 into first discharge plenum 66, second discharge plenum 68 and suction plenum 69. First discharge plenum 66 includes that portion of interior plenum 13 located between crankcase 38 of first compression mechanism 14 and first end member 12 a of housing 12. Second discharge plenum 68 includes the portion of interior plenum 13 located between crankcase 38 of second compression mechanism 16 and second end member 12 b of housing 12. Suction plenum 69 comprises the portion of interior plenum 13 located between the crankcases of first and second compression mechanisms 14, 16. Suction inlet 15 extends through main housing member 12 c and communicates with suction plenum 69. First and second discharge tubes 70, 72 extend through first and second end housing members 12 a, 12 c, respectively, and communicate with respective discharge plenums 66, 68.
Referring now to FIGS. 1 and 4, top member 42 of each of first and second compression mechanisms 14, 16 includes discharge port 56, which provides fluid communication between compression chambers 52 of first and second compression mechanisms 14, 16 and respective discharge plenums 66, 68. As illustrated in FIG. 4, the outer surface of top member 42 defines recess 58 which surrounds and extends from discharge port 56. Discharge valve assembly 60 fits within recess 58 and includes flexible discharge valve member 62, rigid valve retainer 64, and valve fastener 65. Valve assembly 60 is mounted within recess 58 by valve fastener 65, which engages valve fastener opening 67.
Referring to FIGS. 1 and 3, crankcase 38 of each of first and second compression mechanisms 14, 16 defines inlet opening 74 by which the refrigerant flows into compression chamber 52. Compressor assembly 10 can be configured as either a single-stage compressor, in which the refrigerant enters both first and second compressor mechanisms 14, 16 at suction pressure and is compressed therein and discharged at a final pressure, or a two-stage compressor, in which the refrigerant enters first compressor mechanism 14 at suction pressure, is compressed to an intermediate pressure, and is discharged to second compressor mechanism 16 wherein the refrigerant is further compressed to and discharged at a final pressure. In first compressor mechanism 14, inlet opening 74 communicates the refrigerant from suction plenum 69 to compression chamber 52. In second compressor mechanism 16, inlet opening 74 is in fluid communication with compression chamber 52 and either suction plenum 69, if compressor assembly 10 is a single-stage compressor, or first discharge tube 70, if compressor assembly is a two-stage compressor. If compressor assembly is a two-stage compressor, first discharge tube 70 may extend from first end housing member 12 a, through main housing member 12 c, and join inlet opening 74 of second compressor mechanism 16.
Referring now to FIGS. 5-7, the configuration of drive shaft 30 and its engagement with first and second compressor mechanisms 14, 16 will now be described. As noted above, drive shaft 30 is a unitary elongate member including elongate central portion 34 and first and second end portions 32, 36 located on opposite ends of central portion 34. Drive shaft 30 may be made of steel or any other rigid material sufficient to withstand the pressures and forces generated during operation without deformation or deflection. Drive shaft 30 extends along and rotates about rotational axis A-A. Each of first end portion 32, central portion 34 and second end portion 36 defines a cross-sectional configuration oriented perpendicular to rotational axis A-A. As shown in FIGS. 5 and 7, the cross-sectional configuration of central portion 34 is substantially circular, while the cross-sectional configurations of first and second end portions 32, 36 are substantially non-circular. The cross-sectional configurations of first and second end portions 32, 36 define a pair of opposing planar flats 33 which give the cross-sectional configurations of first and second end portions 32, 36 an outer perimeter that is disposed radially within the outer perimeter of the cross-sectional configuration of central portion 34 relative to the rotational axis A-A. The cross-sectional configuration of first and second end portions 32, 36 may be machined into shaft 30 or, alternatively, shaft 30 may be molded to form by any conventional method, such as by investment casting.
Turning to FIG. 6, inner roller 44 of each of the roller assemblies 43 of first and second compressor mechanisms 14, 16 includes an outer cylindrical surface which defines roller axis A₁-A₁. A shaft mounting opening 46 extends through inner roller 44 along a line parallel to but spaced apart from the corresponding roller axis. Opening 46 has a substantially non-circular configuration, which includes a pair of opposing flats 47. The overall configuration of opening 46 is complementary to the cross-sectional configurations of first and second end portions 32, 36 of shaft 30, such that first and second end portions 32, 36 of shaft 30 may be slip-fit into opening 46 of roller 44 of first and second compressor mechanisms 14, 16, respectively. This slip-fit engagement prevents relative rotation of shaft 30 with respect to inner roller 44. Because opening 46 is offset from the corresponding roller axis, the rotation of shaft 30 imparts an orbiting motion to inner roller 44.
As shown in FIG. 1, first and second end portions 32, 36 of drive shaft 30 extend through and are journaled in crankcase 38 of first and second compression mechanisms 14, 16, respectively. Roller 44 of first and second compressor mechanisms 14, 16 is mounted, as described above, on first and second end portions 32, 36 of shaft 30. As shown in FIG. 5, roller 44 of first and second compressor mechanisms 14, 16 may be oriented on shaft 30 such that roller axis A₁-A₁of each of first and second compressor mechanisms 14, 16 are positioned diametrically opposite one another relative to rotational axis A-A. Such an orientation may aid in rotationally balancing shaft 30. In addition or in the alternative, the cross-sectional configurations of first and second end portions 32, 36 may be oriented so as to be rotationally offset from one another relative to rotational axis A-A. More specifically, the cross-sectional configurations of each of first and second end portions 32, 36 defines a line of symmetry which divides the cross-sectional configuration into two symmetrical halves. As shown in FIG. 7, the cross-sectional configurations of first and second end portions 32, 36 may be oriented such that the line of symmetry of first end portion 32 is rotationally offset from the line of symmetry of second end portion 36 by 180° relative to rotational axis A-A.
In alternative embodiments, the cross-sectional configurations of first and second end portions and their corresponding shaft receiving openings may take different shapes. For instance, first and second end portions and their corresponding shaft receiving openings may be square, semi-circular, or pentagonal in cross-section.
As illustrated in FIGS. 1 and 2 and described above, both first and second compressor mechanisms 14, 16 may be rotary-type compression mechanisms. Alternatively, first and second compressor mechanisms may be any type of compression mechanism, including reciprocating-piston mechanisms, orbiting-scroll mechanisms, and rotary-screw mechanisms. For instance, first and/or second compressor mechanisms could be an orbiting-scroll mechanism such as that disclosed in U.S. Pat. No. 5,013,225 to Richardson, Jr. which is assigned to Tecumseh Products Company, the assignee of the present invention and which is hereby incorporated by reference. In this case, the shaft receiving opening may be defined in the hub of the orbiting plate and the shaft may be slip-fit into the opening. It should also be understood that first and second compressor mechanisms need not necessarily be identical to one another. In other words, first compressor mechanism may be of a different type than that of second compressor mechanism.
In operation, rotor 20 rotates about rotational axis A-A which in turn causes the rotation of shaft 30 about axis A-A. The rotation of shaft 30 imparts a rotational force on roller 44 of both first and second compressor mechanisms 14, 16. This rotational force is translated into an orbiting motion of rollers 44 simultaneously within chambers 52 of both first and second compressor mechanisms 14, 16. As roller 44 orbits within chamber 52, it engages sliding vane 50 and the inside wall of cylinder block 40 to cause the crescent-shaped chamber 52 to expand and contract in size and, thereby, draw in and compress the refrigerant within the chambers 52 of first and second compressor mechanisms 14, 16. The refrigerant is drawn into suction plenum 69 at suction pressure via suction inlet 15.
Assuming compressor assembly 10 is a two-stage compressor, the refrigerant flows from suction plenum 69 to compression chamber 52 of first compressor mechanism 15 via inlet opening 74. The refrigerant is compressed within compression chamber 52 of first compressor mechanism 14. When the pressure of the refrigerant within chamber 52 of first compressor mechanism 14 reaches a pressure sufficient to bias valve member 62 away from port 56, the refrigerant is discharged through discharge port 56 into first discharge plenum 66. From discharge plenum 66 the refrigerant enters discharge tube 70 and flows to second compressor mechanism 16 where it enters compression chamber 52 of second compressor mechanism 16 through inlet opening 74 of second compressor mechanism 16. The refrigerant is then compressed to a higher pressure and is discharged through discharge port 56 of second compressor mechanism 16 when the pressure within compression chamber 52 of second compressor mechanism 16 is sufficient to bias valve member 62 away from port 56. From second discharge plenum 68 the refrigerant enters second discharge tube 72 and exits compressor assembly 10.
If compressor assembly 10 is configured as a single-stage compressor, the refrigerant flows from suction plenum 69 into the compression chambers 52 of both first and second compressor mechanisms 14, 16. The refrigerant is then compressed within compression chambers 52 of first and second compressor mechanisms 14, 16 and is discharged through discharge ports 56 and into first and second discharge plenums 66 and 68, respectively. From discharge plenums 66, 68 the refrigerant enters discharge tubes 70, 72, respectively, and exits the compressor assembly 10.
In an alternative embodiment, shown in FIGS. 8-10, compressor 110 generally includes motor assembly 18, first compressor mechanism 114, second compressor mechanism 116, and shaft 130 operably engaged with compressor mechanisms 114 and 116. As shown in FIG. 8, shaft 130 includes a one-piece elongate member defining first end portion 132 and opposite second end portion 136. Shaft 130 extends through central bore 21 in rotor 20 of motor assembly 18 along rotational axis A-A and is rotatably secured to rotor 20 for rotation therewith. First and second end portions 132, 136 of shaft 130 are positioned adjacent opposite ends of motor assembly 18. Each of first and second end portions 132, 136 define a central opening 138 extending axially into first and second end portions 132, 136 along rotational axis A-A.
Referring to FIGS. 8-10, first and second compressor mechanisms 114, 116 each include an eccentric member 144. Each eccentric member 144 includes substantially cylindrical eccentric portion 144 a which defines member axis A₁-A₁, and linking rod 144 b extending from eccentric portion 144 a along a rod axis substantially parallel to but spaced apart from member axis A₁-A₁. In the present embodiment, linking rod 144 b has a substantially cylindrical outer surface 145 and a diameter that is slightly larger than the diameter of central opening 138. As a result, when linking rod 144 b is inserted into opening 138, inner surface 139 of central opening 138 bears against outer surface 145 of linking rod 144 b such that they are in a press-fit, or interference-fit, relationship. Owing to the press-fit relationship, eccentric member 144 does not rotate with respect to shaft 130.
Owing to the press-fit relationship described above, in one embodiment, a set screw, fastener, pin, or welding process is not required to maintain the relative position of eccentric member 144 and shaft 130, as required by previous compressors. Advantageously, the time and cost to machine recesses for receiving the fasteners, pins or set screws can be eliminated. Additionally, these recesses may wear or fret over time allowing the fasteners, pins, or set screws to come loose. Further, owing to the press-fit of eccentric 144 into opening 138, as illustrated in FIGS. 8 and 9, the overall size of the compressor can be reduced. More particularly, in previous compressors, the diameter of the eccentric was determined by the stroke length, or throw, needed to operate the compressor in addition to the diameter of the shaft received therein, thereby resulting in a large eccentric. In the present embodiment, the diameter of eccentric 144, as it is not placed over shaft 130, is not determined by the diameter of shaft 130. Stated in another way, eccentric portion 144 a can be smaller than previous eccentric portions, as it does not need to be enlarged to accommodate shaft 130 therein. As a result, the rollers or pistons operably engaged with eccentrics 144 can be moved closer to the shaft, resulting in a more compact compressor.
To assemble compressor 110, in the present embodiment, first end 132 of shaft 130 is inserted through opening 21 of rotor 20. Thereafter, linking rod 144 b is aligned with opening 138 such that, for example, outer surface 145 of linking rod 144 b is substantially concentric with inner surface 139 of opening 138. Thereafter, a force is applied to eccentric member 144 and/or shaft 130 in a direction substantially parallel to axis A-A. This force causes wall 141 surrounding opening 138 to flex or expand outwardly as linking rod 144 b is pressed into opening 138. A second eccentric member 144 can then be assembled to second end portion 136. Alternatively, the second eccentric member 144 can be assembled to shaft 130 prior to inserting first end 132 through opening 21 of rotor 20. In a further alternative embodiment, the second eccentric can be integral with shaft 130. In this embodiment, second end 136 is not inserted through opening 21, and thus, the eccentric may be integral with the shaft.
In the illustrated embodiment, each eccentric member 144 includes a recess or groove 146 which extends around the circumference of linking rod 144 b. Shaft 130 also includes grooves 140 which extend around the outer circumference of first and second end portions 132 and 136 (not shown at end portion 132) and lubricant apertures 162 which extend between the inside surface of shaft 130 and grooves 140. In operation, grooves 146 of linking rods 144 b cooperate with lubricant apertures 162 of shaft 130 to define a lubrication passage between the interior of shaft 130 and the outside surface of shaft 130. In use, oil flows from lubricant apertures 162 into grooves 146 on the outside surface of shaft 130 to lubricate the relative rotational movement between the shaft and bearings supporting the shaft, for example. In the present embodiment, each eccentric member 144 further includes a lubricant aperture 160 which extends between end 161 of linking rod 144 b and the outside surface of eccentric portion 144 a. In operation, oil can flow from the interior of shaft 130 to the outside surface of eccentric member 144 to lubricate the relative rotational movement between linkage key 150 and eccentric member 144, as described in further detail below.
In an alternative embodiment, eccentric members 144 may have recesses in lieu of linking rods 144 b that engage end portions 132 and 136 of shaft 130 in a press-fit relationship. In one embodiment, the recesses have non-circular geometries and end portions 132 and 136 have complementary non-circular cross-sections that are closely received and press-fit within the recesses of eccentric members 144.
As discussed above, an eccentric member 144 may be mounted to each of first and second end portions 132, 136 of shaft 130 by press fitting linking rod 144 b into central opening 138. Alternative means may be provided for securing rod 144 b in central opening 138. To achieve optimum balance eccentric members 144 may be oriented on shaft 130 such that member axis A₁-A₁of each of first and second compressor mechanisms 114, 116 are positioned diametrically opposite one another relative to rotational axis A-A.
As illustrated in FIGS. 9-10, first and second compressor mechanisms 114, 116 may be reciprocating piston-type compressor mechanisms. First and second compressor mechanisms 114, 116 each includes piston 149 which operably engages eccentric member 144 through linkage key 150. Linkage key 150 includes a ring portion 150 a which is rotatably mounted about cylindrical eccentric portion 144 a of eccentric member 144. Ring portion 150 a includes a lubrication passage 164 for communicating lubrication fluid to the mating surfaces of ring portion 150 a and eccentric portion 144 a. Linkage key 150 also includes a linkage arm 150 b which extends from linkage ring and engages piston 149 in a conventional manner. The rotation of shaft 130 about rotational axis A-A imparts a rotational force on eccentric member 144 causing eccentric member 144 to orbit about rotational axis A-A. The orbiting motion of eccentric member 144 imparts a reciprocating motion to piston 149 within cylindrical chamber 148 through linkage key 150.
While FIGS. 9-10 illustrate compressor mechanisms 114 and 116 as reciprocating piston-type mechanisms, it is contemplated that other compressor mechanisms may be used. For instance, member 144 could serve as the inner roller of a rotary-type compressor mechanism and, therefore, a rotary-type compressor mechanism could be mounted to the opposite ends of drive shaft 130.
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.

Claims

1. A compressor, comprising:

a motor including a rotor;

a driveshaft operably engaged with said rotor, said driveshaft including a first end extending from said rotor; and

a first eccentric press-fit to said first end of said driveshaft.

2. The compressor of claim 1, wherein said driveshaft includes an opening, said opening including an inside surface, and wherein said inside surface of said opening bears against an outside surface of said first eccentric.

3. The compressor of claim 1, wherein said driveshaft includes an opening, wherein said first eccentric includes a linking rod, and wherein said linking rod is press-fit into said opening.

4. The compressor of claim 4, wherein said linking rod includes a recess in fluid communication with said driveshaft opening, and wherein said driveshaft includes a lubricant aperture in fluid communication with said recess, whereby lubricant may flow between said driveshaft opening and an outside surface of said driveshaft.

5. The compressor of claim 1, further including a second eccentric press-fit to a second end of said driveshaft.

6. The compressor of claim 5, wherein said driveshaft includes a second opening, wherein said second eccentric includes a linking rod, and wherein said linking rod is press-fit into said second opening.

7. The compressor of claim 1, wherein the engagement of said first eccentric and said driveshaft is fastener-less.

8. A compressor, comprising:

a motor;

a driveshaft operably engaged with said motor; and

a first eccentric, wherein one of said driveshaft and said first eccentric includes a first opening, and wherein the other of said driveshaft and said first eccentric is press-fit into said first opening.

9. The compressor of claim 8, wherein said driveshaft includes said opening, said opening including an inside surface, and wherein said inside surface of said opening bears against an outside surface of said first eccentric.

10. The compressor of claim 8, wherein said driveshaft includes said opening, wherein said first eccentric includes a projection, and wherein said projection is press-fit into said opening.

11. The compressor of claim 10, wherein said projection includes a recess in fluid communication with said driveshaft opening, and wherein said driveshaft includes a lubricant aperture in fluid communication with said recess, whereby lubricant may flow between said driveshaft opening and an outside surface of said driveshaft.

12. The compressor of claim 8, further including a second eccentric, wherein one of said driveshaft and said second eccentric includes a second opening, and the other of said driveshaft and said second eccentric is press-fit into said second opening.

13. The compressor of claim 12, wherein said driveshaft includes said second opening, wherein said second eccentric includes a second projection, and wherein said second projection is press-fit into said second opening.

14. The compressor of claim 8, wherein the engagement of said first eccentric and said driveshaft is fastener-less.

15. A method of assembling a compressor, comprising the steps of:

inserting a first end of a driveshaft through an opening in a rotor;

securing the rotor to the driveshaft; and

press-fitting a first eccentric to the first end of the driveshaft.

16. The method of claim 15, wherein the first end of the driveshaft includes a first opening, wherein the first eccentric includes a projection, and wherein said pres-fitting step includes the step of aligning the projection of the first eccentric with the first opening of the driveshaft and forcing the projection into the opening.

17. The method of claim 15, wherein the driveshaft includes a second end, said method further comprising the step of press-fitting a second eccentric to the second end of the driveshaft.

18. The method of claim 17, wherein the second end of the driveshaft includes a second opening, wherein the second eccentric includes a second projection, and wherein said pres-fitting step includes the step of aligning the second projection of the second eccentric with the second opening of the driveshaft and forcing the second projection into the second opening.