CROSS-REFERENCE TO RELATED APPLICATIONS

[01] This patent application claims the priority benefit under 35 U.S.C. §

1 19(e) of U.S. Provisional Application No. 62/564,630, filed on September 28, 2017, the contents of which are herein incorporated by reference.

BACKGROUND OF THE INVENTION

1 . Field of the Invention

[02] The present disclosure pertains to methods and systems for versatile

housing of different sized motors in a reciprocating compressor.

2. Description of the Related Art

[03] Pumps, blowers, and compressors are generally used in industrial,

commercial, healthcare, consumer goods, and medical device applications.

Reciprocating compressors use pistons driven by a crankshaft. Typically, crankshafts of reciprocating (piston) compressors are operated by a motor housed in a generally cylindrical motor housing. The motor housing may couple to an outer or inner surface of crankcases. For each different motor in each particular application, the motor housing and/or the crankcase are often modified for fitting within the pump, blower, compressor, or other mechanical system. Therefore, there remains a need for improving existing compressors to avoid such significant and costly modifications to the constituent components of a compressor (e.g., to the crankcases, motor housing, assembly fixtures, etc.) when the application requires a differently sized motor or motor stator.

SUMMARY

[04] Accordingly, one or more aspects of the present disclosure relate to a compressor assembly configured to operatively couple to differently dimensioned motor stators in a reciprocating compressor. In some embodiments, the compressor comprises: a cylinder forming a space for compressing a fluid; a crankshaft housing operatively coupled to the cylinder; a crankshaft housed within the crankshaft housing; a rod assembly configured to reciprocate within the cylinder so as to compress the fluid within the space, the rod assembly being driven by the crankshaft; a motor housing operatively coupled to the crankshaft housing; and a motor housed within the motor housing. The motor is configured to drive the crankshaft.

[05] More specifically, in some embodiments, the motor housing may be

operatively coupled to the crankshaft housing, and the motor housing may be further configured to be operatively coupled to another crankshaft housing. The motor housing may comprise a first inner sidewall, a first outer sidewall, a second inner sidewall, a second outer sidewall, and an intermediate portion interposed between the first outer sidewall and the second inner sidewall. In some embodiments, the first inner and first outer sidewalls may form at least part of a first cylindrical shell, the second inner and second outer sidewalls may form at least part of a second cylindrical shell, at least one of the first or second cylindrical shell may be configured such that the first and second cylindrical shells have different axial lengths, and at least one of the first or second cylindrical shell may be configured such that the first and second cylindrical shells have different radial lengths.

[06] Another aspect of the present disclosure relates to a method for

operatively coupling a compressor assembly to differently dimensioned motor stators in a reciprocating compressor. In some embodiments, the method is implemented with respect to the compressor, which comprises a cylinder, a crankshaft housing, a crankshaft, a rod assembly, a motor housing, and a motor. In some embodiments, the motor housing comprises a first inner sidewall, a first outer sidewall, a second inner sidewall, a second outer sidewall, and an intermediate portion. The intermediate portion may be interposed between the first outer sidewall and the second inner sidewall. The first inner and first outer sidewalls may form at least part of a first cylindrical shell, and the second inner and second outer sidewalls may form at least part of a second cylindrical shell. In some embodiments, the method includes: forming, with the cylinder, a space for compressing a fluid; operatively coupling the crankshaft housing to the cylinder; housing the crankshaft within the crankshaft housing; operatively coupling the motor housing to the crankshaft housing; housing the motor within the motor housing, the motor being configured to drive the crankshaft; reciprocating the rod assembly within the cylinder so as to compress the fluid within the space, the rod assembly being driven by the crankshaft; operatively coupling the motor housing to the crankshaft housing, the motor housing being further configured to be operatively coupled to another crankshaft housing; configuring at least one of the first or second cylindrical shell such that the first and second cylindrical shells have different axial lengths; and configuring at least one of the first or second cylindrical shell such that the first and second cylindrical shells have different radial lengths.

[07] Still another aspect of the present disclosure relates to a system configured to operatively couple a compressor assembly to differently dimensioned motor stators. In some embodiments, the system comprises: means for forming a space for compressing a fluid; means for housing a crankshaft operatively coupled to the means for forming the space; means for reciprocating within the means for forming the space so as to compress the fluid within the space, the means for reciprocating being driven by the crankshaft; and means for housing a motor that drives the crankshaft. In some embodiments, the means for housing the motor is operatively coupled to the means for housing the crankshaft, and the means for housing the motor is further configured to be operatively coupled to another means for housing a crankshaft.

[08] In some embodiments, the means for housing the motor comprises: first means for forming an inner sidewall, first means for forming an outer sidewall, second means for forming an inner sidewall, second means for forming an outer sidewall, and means for interposing between the first means for forming the outer sidewall and the second means for forming the inner sidewall. In some embodiments, the first means for forming the inner sidewall and the first means for forming the outer sidewall may form at least part of a first cylindrical shell, and the second means for forming the inner sidewall and the second means for forming the outer sidewall may form at least part of a second cylindrical shell. In some embodiments, at least one of the first or second cylindrical shell is configured such that the first and second cylindrical shells have different axial lengths, and at least one of the first or second cylindrical shell is configured such that the first and second cylindrical shells have different radial lengths. [09] Yet another aspect of the present disclosure relates to a motor housing operatively coupled to a crankshaft housing and configured to be operatively coupled to another crankshaft housing. In some embodiments, the motor housing comprises a first inner sidewall, a first outer sidewall, a second inner sidewall, a second outer sidewall, and an intermediate portion interposed between the first outer sidewall and the second inner sidewall. In some embodiments, the first inner and first outer sidewalls form at least part of a first cylindrical shell, the second inner and second outer sidewalls form at least part of a second cylindrical shell, and at least one of the first or second cylindrical shell is configured such that the first and second cylindrical shells have different axial lengths.

[10] Still another aspect of the present disclosure relates to a motor housing operatively coupled to a crankshaft housing and configured to be operatively coupled to another crankshaft housing. In some embodiments, the motor housing comprises a first inner sidewall, a first outer sidewall, a second inner sidewall, a second outer sidewall, and an intermediate portion interposed between the first outer sidewall and the second inner sidewall. In some embodiments, the first inner and first outer sidewalls form at least part of a first cylindrical shell, the second inner and second outer sidewalls form at least part of a second cylindrical shell, and at least one of the first or second cylindrical shell is configured such that the first and second cylindrical shells have different radial lengths.

[11] These and other objects, features, and characteristics of the present

disclosure, as well as the methods of operation and functions of the related elements of structure and the combination of parts and economies of manufacture, will become more apparent upon consideration of the following description and the appended claims with reference to the accompanying drawings, all of which form a part of this specification, wherein like reference numerals designate corresponding parts in the various figures. It is to be expressly understood, however, that the drawings are for the purpose of illustration and description only and are not intended as a definition of the limits of the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

[12] FIG. 1 is a schematic illustration of a cross-sectional view of a twin-head, reciprocating compressor with housings; [13] FIG. 2A illustrates an exemplary twin-head, reciprocating compressor with housings;

[14] FIG. 2B illustrates an exemplary motor housing;

[15] FIG. 3 A illustrates an isometric view of an exemplary crankcase with different surfaces for mating to a motor housing, in accordance with one or more embodiments;

[16] FIG. 3B illustrates an isometric view of another exemplary crankcase with different surfaces for mating to a motor housing, in accordance with one or more embodiments;

[17] FIG. 4 illustrates an exemplary cross-sectional view of a motor, in

accordance with one or more embodiments;

[18] FIG. 5 illustrates isometric views of exemplary motors having different stack lengths, in accordance with one or more embodiment;

[19] FIG. 6A illustrates isometric views of an exemplary motor housing, in accordance with one or more embodiments;

[20] FIG. 6B illustrates a planar view of an exemplary motor housing, in

accordance with one or more embodiments;

[21] FIG. 7 illustrates an exemplary cross-sectional view of a motor housing, in accordance with one or more embodiments;

[22] FIG. 8A is a schematic illustrations of a cross-sectional view of a twin- head, reciprocating compressor with motor and housings, in accordance with one or more embodiments;

[23] FIG. 8B is a schematic illustrations of a cross-sectional view of a twin- head, reciprocating compressor with motor and housings, in accordance with one or more embodiments;

[24] FIG. 9A illustrates in an isometric view an exemplary motor housing, in accordance with one or more embodiments;

[25] FIG. 9B illustrates in an isometric view an exemplary motor housing, in accordance with one or more embodiments; [26] FIG. 9C illustrates in an isometric view an exemplary motor housing, in accordance with one or more embodiments;

[27] FIG. 9D illustrates in an isometric view an exemplary motor housing, in accordance with one or more embodiments;

[28] FIG. 10 illustrates a method for versatile housing of different sized motors in a reciprocating compressor;

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

[29] As used herein, the singular form of "a," "an," and "the" include plural references unless the context clearly dictates otherwise. As used herein, the statement that two or more parts or components are "coupled" shall mean that the parts are joined or operate together either directly or indirectly, i.e., through one or more intermediate parts or components, so long as a link occurs. As used herein, "directly coupled" means that two elements are directly in contact with each other. As used herein, "fixedly coupled" or "fixed" means that two components are coupled so as to move as one while maintaining a constant orientation relative to each other.

[30] As used herein, the word "unitary" means a component is created as a single piece or unit. That is, a component that includes pieces that are created separately and then coupled together as a unit is not a "unitary" component or body. As employed herein, the statement that two or more parts or components "engage" one another shall mean that the parts exert a force against one another either directly or through one or more intermediate parts or components. As employed herein, the term "number" shall mean one or an integer greater than one (i.e., a plurality).

[31] Directional phrases used herein, such as, for example and without

limitation, top, bottom, left, right, upper, lower, front, back, and derivatives thereof, relate to the orientation of the elements shown in the drawings and are not limiting upon the claims unless expressly recited therein.

[32] FIG. 1 illustrates compressor 10. In some embodiments, compressor 10 includes cylinders 12a and 12b for compressing a fluid, such as a liquid or gas, rod assemblies 14a and 14b, crankshafts 72a and 72b, and/or other components. The number of cylinders and crankcases used in the examples herein is not to be construed as limiting, since the disclosed embodiments may apply to pumps, blowers, or compressors having other arrangements and any number of cylinders and crankcases. Rod assemblies 14a and 14b may be configured to reciprocate in cylinders 12a and 12b, respectively, so as to compress the fluid. Crankshafts 72 a and 72b may be configured to drive rod assemblies 14a and 14b within cylinders 12a and 12b, respectively. Rod assemblies 14a and 14b include one or more valves 52a and 52b and cup seals 60a and 60b and/or other components. Volume clearance is a space remaining within cylinders 12a and 12b when rod assemblies 14a and 14b are at the most advanced position in their travel within cylinders 12a and 12b. Managing clearance volume may enhance the compressor's performance. Compressor 10 may be used in oil-less applications where service is performed to replace worn-out cup seals after a given number of hours of operation (e.g., medical oxygen concentrator compressors) and/or in other applications.

[33] First crankshaft housing 18a encloses first crankshaft 72a, is operatively coupled to first rod assembly 14a, and is configured to drive first rod assembly 14a. In some embodiments first crankshaft 72a is operatively coupled with motor shaft 16 that provides torsional energy from motor 76 (shown in FIGS. 4, 5, and 8), which is housed within motor housing 22. As illustrated in FIG. 1 , motor shaft 16 is operatively coupled with second crankshaft 72b, which is housed within second crankshaft housing 18b located at first side 44 along second side 46 of compressor assembly 10.

[34] In some embodiments, motor 76 is an electric motor. In some

embodiments, motor 76 operates within a compressor, pump, blower, or other mechanical device. Motor 76 may be self-commutated and/or externally-commutated, including, e.g., universal motors, alternating current (AC) motors, direct current (DC) motors, or other types of motors. More specifically, motor 76 may be a permanent split capacitor AC induction motor, a brush DC motor, a permanent magnet brushless DC motor, a stepper motor, a shaded pole motor, a switch reluctance motor, or another particular type of motor. For a further description of motor 76, see the description of FIG. 4, below.

[35] In some embodiments, first crankshaft 72a is configured to drive first rod assembly 14a to compress gas within first reciprocating space 1 1a. Similarly, second crankshaft 72b may be configured to drive second rod assembly 14b to compress gas within second reciprocating space 1 lb. Second space 1 lb may be defined by second rod assembly 14b, second cylinder 12b, and second cap seal 13b on along second side 46 of compressor assembly 10. The components along second side 46 of compressor assembly 10 may be the same and/or similar to the components located along third side 42 of the compressor assembly 10. For example, first cap seal 13a located at fourth side 40 and along third side 42 may be the same as and/or similar to second cap seal 13b located along second side 46.

[36] In some embodiments, compressor 10 has a tandem arrangement with cylinders 12a and 12b, having a rod assembly 14a and 14b received therein. A motor shaft 16 is configured to couple the motor to crankshafts 72a and 72b, which are coupled with one of the rod assemblies 14a and 14b, so that the movement of rod assemblies 14a and 14b may oppose each other.

[37] In some embodiments, rod assemblies 14a and 14b are configured to alternately reciprocate within cylinders 12a and 12b, respectively, so as to compress the fluid. Crankshafts 72a and 72b are configured to drive pistons 14a and 14b within cylinders 12a and 12b. Crankshafts 72a and 72b are housed in crankcases or crankshaft housings 18a and 18b that are operatively coupled with cylinders 12a and 12b, respectively. Crankcases 18a and 18b may each be associated with one of cylinders 12a or 12b. Motor 76 is operatively coupled with the crankshafts 72a and 72b and is configured to drive crankshafts 72a and 72b. Motor 76 may be housed in motor housing 22, which may be operatively coupled with crankcases 18a and 18b.

[38] As shown in FIG. 1 , rod assemblies 14a and 14b may have lower ends 68a and 68b with bearing centers 71a and 71b configured to receive a portion of the crankshafts 72a and 72b, respectively. Crankshafts 72a and 72b may be offset and thus not in linear correlation to the axis of motor shaft 16.

[39] In some embodiments, motor housing 22 includes motor 76 configured to drive crankshafts 72a and 72b. Motor shaft 16 rotates crankshafts 72a and 72b, which in turn causes rod assemblies 14a and 14b to reciprocate upwardly and downwardly within cylinders 12a and 12b. This configuration enables compressor assembly 10 to increase the pressure of the fluid. [40] In some embodiments, motor 76 is coupled to housing or shell 22, as shown in FIGS. 1 , 2A, and 2B. More specifically, in some embodiments, motor stator 77 is coupled to shell 22 and motor 76 envelops motor shaft 16, as shown in FIG. 1 , 2A, 2B, 4, and 5. In some embodiments, as shown in FIGS. 1-5, motor stator 77, motor stator windings 75, motor rotor 74, motor bearing 73, and motor shell 22 are assembled together, with respect to crankcase housings 18a and 18b. Crankshaft housings or crankcases 18a and 18b may then be assembled onto respective ends of motor 76 (e.g., through the use of bearings 69a, 69b, 70a, and/or 70b). Some or more of these machine (e.g., compressor) components may be coupled to respective faces or surfaces of each other via any suitable mechanical means, such as via adhesive and/or other coupling components. For example, an adhesive may operate at their interfaces, as depicted with respect to outer sidewall surface 19a of crankcase 18a (or 18b) and an inner sidewall surface of motor housing 22 in FIGS. 1 and 3 A. In other embodiments, as depicted in the examples given by FIGS. 3B and 8B, the interface comprises inner sidewall 19b of crankcase 18a (or 18b) and an outer sidewall of motor housing 22.

[41] In some embodiments, the versatile motor housing (e.g., motor housing

22) is configured to be machined such that installation of different motors into the compressor does not require modification to the corresponding crankcase (e.g., crankcases 18a and 18b). For example, one set of crankcases 18a and 18b may be coupled to various, different motors via motor housing 22. Motor housing 22 may be configured (e.g., machined to size) to facilitate its adaptation to any of a variety of different applications or compressor platforms. See further description of motor housing 22, below.

[42] Crankcases 18a and 18b may be die cast (e.g., of aluminum, magnesium, zinc alloys, steel, iron, or another suitable material) to form its various shapes and features, as shown, e.g., in FIGS. 3A-3B. Similarly, motor housing 22 may be die cast (e.g., of aluminum, magnesium alloys, zinc alloys, steel, iron, ceramic, plastic, composite, or another suitable material). When conventionally coupling a crankcase to different motors (e.g., motors with differing stack lengths), the crankcases may require extensive machining, replacement, and/or other modifications. The modifications may include changes to the assembly fixtures. Tighter tolerances may be achieved by machining the die cast component. Both the die cast process and each machining process incurs tooling costs, the tooling costs becoming significant in conventional application(s) requiring multiple compressor or motor platforms (e.g., with different stack lengths and other dimensions). In some embodiments, motor housing 22 advantageously minimizes these costs by being configured to facilitate machining of its dimensional details (e.g., of its radial and/or axial lengths, as discussed in greater detail below) without requiring modification to assembly fixtures and/or to crankcases 18a and 18b.

[43] Some embodiments may simplify the process to accommodate different motor stack lengths. Some embodiments facilitate a substantially static footprint or form factor for the compressor upon first determining or establishing the footprint or form factor. That is, in some embodiments, one instantiation of motor housing 22 may accommodate multiple types, models, and/or sizes (i.e., motors of varying efficiencies, rates, costs, etc.) of motors 76, while requiring minimal or no change to the

corresponding crankcases 18a and 18b. Motor housing 22 is thus configured to be versatile and cost-effective, requiring minimal or no external dimensional change to compressor 10. In some embodiments, even isolation mounts for securing compressor 10 may become standardized, being thus independent of a compressor's components' weight, shape, or size.

[44] In some embodiments, one or more features on motor housing 22 are

configured to be machined, rendering the component more versatile with respect to different motors 76. For example, as shown in FIGS. 3 A and 8A, outer sidewall 19a of crankcase housing 18a may mate with inner sidewall 25 of motor housing 22. Inner sidewall 25 may be concentric, at a second level (i.e., at a larger radial length), with respect to inner sidewall 23, at a first level (i.e., at a shorter radial length). As motor 76 shortens axially from one motor to the next, as shown in FIG. 5, an inner ring (or shell) of motor housing 22 may be axially machined shorter. In some embodiments, only this inner ring (comprising inner and outer sidewalls 23 and 24, respectively) is shortened. In other embodiments, both the inner and outer rings are axially shortened; in still other embodiments, just the outer ring is axially shortened. Axial lengths (ALs) of inner ring 31 and outer ring 32 may be the same, but disclosed embodiments do not require them to be the same, as shown in FIG. 7, where AL1 and AL2 are depicted different from each other. Resulting from this versatility of motor housing 22, the compressor may axially shorten and clearance volumes on either side of motor 76 may be minimized.

[45] FIG. 2A illustrates an exemplary twin-head, reciprocating compressor with housings and FIG. 2B illustrates an exemplary motor housing. In some

embodiments, axial screws 33 are used to secure crankcases 18a and 18b to both sides of motor housing 22. Motor housing 22 may, in some embodiments, include openings 21. Openings 21 may be of any quantity and shape (e.g., circular, square, polygonal, kidney- shaped, etc.), in providing air flow within motor housing 22.

[46] FIGS. 3A-3B illustrate isometric views of exemplary crankcases with different surfaces for mating to a motor housing, in accordance with one or more embodiments. In some embodiments, crankcase 18a may be die cast or otherwise fabricated as shown, for example, in FIGS. 3 A and 3B. FIG. 3 A depicts outer surface 19a for mating to an inner surface of motor housing 22. FIG. 3B depicts inner surface 19b for mating to an outer surface of motor housing 22.

[47] FIG. 4 illustrates an exemplary cross-sectional view of a motor, in

accordance with one or more embodiments. Compressor 10 may include different motors of different types, models, and/or sizes (e.g., with different radial or axial stack lengths) to work in a same use-case (e.g., a particular application). Motor 76 may include stator 77, windings 75, rotor 74, bearing 73, and shaft 16. In some embodiments, motor 76 may be conventional in its size and/or functionality. In some embodiments, motor 76 has a shape, as shown in FIG. 4, and in other embodiments motor 76 may be of another shape (e.g., annular). Each of the different motors may be differently sized, dimensioned, and/or shaped (e.g., a circular, square, or any other polygonal shape such as pentagonal, hexagonal, octagonal, etc.), and the motor may require a differently sized, dimensioned, and/or shaped housing (e.g., a circular, square, or any other polygonal shape such as pentagonal, hexagonal, octagonal, etc.). Coupling a motor housing (e.g., motor housing 22) to different motors that are, e.g., smaller, typically complicates the fitting. That is, proper fitting typically requires changes to the respective components, including in some instances a flaring out on the ends of the motor housing for coupling to an existing crankcase and in other instances changes to both the crankcase and the motor housing. Disclosed embodiments may overcome one or more of these limitations.

[48] FIG. 5 illustrates isometric views of exemplary motors having different

(axial) stack lengths, in accordance with one or more embodiments. In some

embodiments, motor housing 22 has an axial length that can accommodate motor 76 with a largest stack length, such as motor 76 shown to the left of the other motors 76. Upon selecting or establishing a form factor for motor housing 22, the form factor may be used with any of a variety of different motors 76. The chosen form factor may thus support a maximally sized motor and all smaller motors. In supporting all smaller motors, crankcase 18a may remain the same. Crankcase 18a and/or motor housing 22 may thus become standardized for supporting multiple, different motors 76.

[49] FIG. 6A illustrates isometric views of an exemplary motor housing and

FIG. 6B illustrates a planar view of the exemplary motor housing, in accordance with one or more embodiments. Motor housing 22 may include first inner sidewall 23, first outer sidewall 24, second inner sidewall 25, second outer sidewall 26, and intermediate portion 27. Intermediate portion 27 may be interposed between first outer sidewall 24 and second inner sidewall 25. First inner sidewall 23 and first outer sidewall 24 may form at least part of first cylindrical ring or shell 31 , as shown in FIG. 7. Similarly, second inner sidewall 25 and second outer sidewall 26 may form at least part of second cylindrical ring or shell 32, as shown in FIG. 7. These shells may be generally (e.g., not perfectly) cylindrical. And the generally cylindrical second shell 32 may span at least part of the axial length of motor 76 (e.g., not including motor shaft 16, which may extend axially outwards towards crankcases 18a and 18b). Shell 32 may include a recessed, circumferential portion 29, as shown in FIGS. 6-8 and 9A-9B. That is, in some embodiments, motor housing 22 may include rectangular recess 29 along a central portion of second cylindrical shell 32 (and/or first cylindrical shell 31).

[50] In some embodiments, intermediate portion 27 may include openings 28.

FIGS. 6A, 6B, 9B, and 9C depict different types and arrangements of these openings, which are used, e.g., for convective cooling. For example, openings or holes 28 may all be kidney-shaped, circular, or a combination of kidney-shaped and circular. In some embodiments, openings 28 may be of another shape or size than is depicted in FIGS. 6 and 9. That is, openings 28 may be, in some embodiments, square (or other polygon) shaped, oval shaped, and/or other suitably shaped. One or more or all of openings 28 may partially traverse or fully pass through intermediate portion 27. These openings may provide cooling and/or weight reduction benefits. Openings 28 of intermediate portion 27 may cause intermediate portion 27 to increase in surface area for enhanced (e.g., convective) cooling.

[51] Openings 21 may also be on the outer surface of motor housing 22, as shown in FIGS. 1 , 2A, and 2B, enabling, e.g., a fan to blow on the compressor for cooling purposes (e.g., for cooling at least the motor and the area at the bearings).

Openings 21 on the outer surface of motor housing 22 and slots 55a of crankcase 18a, as shown in FIG. 1, provide cross-ventilation. In some embodiments, as depicted in FIGS. 9A and 9D, motor housing 22 may have no openings, openings 21 and/or 28 being thus optional for at least weight reduction or more efficient cooling.

[52] FIG. 7 illustrates an exemplary cross-sectional view of motor housing 22, in accordance with one or more embodiments. In some embodiments, motor housing 22 has variable axial lengths (ALs). For example, in some embodiments, AL1 of the inner ring is greater than AL2 of the outer ring and in others AL2 is greater than AL1 , the latter being shown in FIG. 7. In some embodiments, AL1 is the same as AL2. In some embodiments, an axial length of intermediate portion 27 is the same as axial lengths of the first cylindrical shell (AL1) and the second cylindrical shell (AL2). In other embodiments, an axial length of intermediate portion 27 is different than AL1 and/or AL2. In some embodiments, AL1 and/or AL2 are less than a stack length of motor 76. In other embodiments, AL1 and/or AL2 are greater than a stack length of motor 76. These relative lengths are merely provided as a general reference, as the present disclosure is not limited to any particular size or dimension of any of the various different components and pieces of compressor 10.

[53] As shown in FIG. 7, in some embodiments, motor housing 22 has variable radial lengths (RLs), including variable thicknesses of inner and outer rings 31 and 32. For example, in some embodiments, RLl and RL2 of inner ring 31 are different than RL3 and RL4 of outer ring 32. In other words, RLl, RL2, RL3, and RL4 may all be different from one another. This versatility may enable motor housing 22 to couple at least a portion of its inner sidewall 23 (i.e., of the inner ring) or at least a portion of its inner sidewall 25 (i.e., of the outer ring) to an outer surface of a variety of different motor stators. At least a portion of inner sidewall 23 or inner sidewall 25 may also be coupled to outer surface 19a of crankcase 18a. In other embodiments, at least a portion of outer sidewall 24 (i.e., of the inner ring) or outer sidewall 26 (i.e., of the outer ring) may couple to inner surface 19b of crankcase 18a. In the exemplary embodiment where the inner ring is used to couple to crankcase 18a, the outer ring may be machined to be much shorter axially than the inner ring, further enabling weight reduction. In some

embodiments, RLl has a range of about 0.2 inches to 48.0 inches. In some embodiments, RL4 has a range of about 0.27 inches to 60.0 inches. In some embodiments, the lengths of RL2 and RL3 are in between the lengths of RLl and RL4. These exemplary lengths are merely provided as a general reference, as the present disclosure is not limited to any particular size or dimension of any of the various different components and pieces of compressor 10. Each of the radial lengths may in some embodiments comprise a radius of motor housing 22, e.g., extending from an axial center of housing 22 to a surface (or center) of the housing (or ring).

In some embodiments, inner ring 31 or outer ring 32 is machined such that RLl or RL3 increases. RLl or RL3 may increase by removing material of the respective ring in the machining process, effectively thinning the ring. For example, inner ring 31 may be machined to a variable extent to accommodate motor stator 77, which may have a radial length that is greater than RLl (or even RL2). In another example, outer ring 32 may be machined before coupling to crankcase 18a. In some embodiments, inner ring 31 is configured such that a portion of the ring is machined, and in other embodiments the entire inner ring is machined to remove the inner ring, resulting in just intermediate portion 27 and outer ring 32. In some embodiments, intermediate portion 27 may be machined. In some of these embodiments, intermediate portion 27 may be machined out entirely, resulting in just the outer ring. The amount of machining of the inner or outer ring may depend on axial and radial lengths of motor stator 77 and on (e.g., orientation or dimensions) of the mating surface of crankcase 18a.

[55] FIGS. 8A-8B are schematic illustrations of a cross-sectional view of a twin-head, reciprocating compressor with motor and housings, in accordance with one or more embodiments. Motor 76 may cooperate with other components (e.g., bearings 68a, 69a, crankshaft 72a, windings 75, and/or stator 77) for turning motor shaft 16. Motor housing 22 may couple to, adhere to, and/or envelop motor 76. Motor housing 22 may further couple to crankcase 18a via one or more surfaces of either its inner or outer ring. For example, as shown in FIG. 8A, second inner sidewall 25 may couple to outer surface 19a of crankcase 18a. In another example, as shown in FIG. 8B, second outer sidewall 26 may couple to inner surface 19b of crankcase 18a. Although described with respect to just one crankcase (i.e., crankcase 18a), the same coupling techniques described herein apply to other crankcase (e.g., crankcase 18b).

[56] Although FIGS. 8A and 8B show crankcase housings 18a and 18b coupled to the outer ring of motor housing 22, this is not to be interpreted as limiting. That is, in some embodiments, crankcase housings 18a and 18b may couple to the inner ring of motor housing 22. In these latter embodiments, the outer ring may be machined to a minimal axial length. Various different motors may couple to the crankcases by adhering to either inner sidewall 23 or inner sidewall 25 of the inner or outer ring, respectively. In some embodiments, one set of compressor manufacturing assembly fixtures may be used with motors of varying diameters resulting in a simplified and efficient compressor assembly process.

[57] FIGS. 9A-9D illustrate in isometric views exemplary motor housings, in accordance with one or more embodiments. Motor housing 22, in some embodiments, may itself take different forms, sizes, and shapes, as shown in the examples of FIGS. 6A, 6B, 7, and 9A-9D. For example, one of an inner sidewall or an outer sidewall of motor housing 22 may be used when coupling to motor 76, these sidewalls having different axial and radial lengths. FIG. 7 shows motor housing 22 having two levels at differing radial lengths, these levels being described, e.g., as an inner ring and an outer ring. Each of the different surfaces may be used for mating or mounting to crankcase housing 18a. That is, the example of FIG. 7 depicts four mounting surfaces (i.e., outer sidewall 26 of the outer ring, inner sidewall 25 of the outer ring, outer sidewall 24 of the inner ring, or inner sidewall 23 of the inner ring).

[58] FIG. 10 illustrates a method 100 for operatively coupling a compressor assembly to differently dimensioned motor stators in a reciprocating compressor. The compressor includes a cylinder, a crankcase, a crankshaft, a motor housing, a motor, and a rod assembly, and/or other components.

[59] The operations of method 100 presented below are intended to be

illustrative. In some embodiments, method 100 may be accomplished with one or more additional operations not described, and/or without one or more of the operations discussed. Additionally, the order in which the operations of method 100 are illustrated in FIG. 10 and described below is not intended to be limiting. The operations of FIG. 10 may be executed in any order (i.e., not necessarily as shown in FIG. 10).

[60] At operation 102, a space for compressing a fluid is formed via a cylinder.

In some embodiments, operation 102 is performed by a cylinder the same as or similar to cylinder 12a (shown in FIG. 1 and described herein).

[61] At operation 104, a crankcase is operatively coupled to the cylinder. In some embodiments, operation 104 is performed by a crankcase the same as or similar to crankcase 18a (shown in FIG. 1 and described herein).

[62] At operation 106, a crankshaft is housed within the crankcase. In some embodiments, operation 106 is performed by a crankshaft the same as or similar to crankshaft 72a (shown in FIG. 1 and described herein).

[63] At operation 108, a first cylindrical shell is formed by a first inner sidewall and a first outer sidewall of a motor housing. In some embodiments, operation 108 is performed by a first inner sidewall and a first outer sidewall the same as or similar to first inner sidewall 23 and first outer sidewall 24 (shown in FIGS. 6-8 and described herein).

[64] At operation 110, a second cylindrical shell is formed by a second inner sidewall and a second outer sidewall of the motor housing. In some embodiments, operation 110 is performed by a second inner sidewall and a second outer sidewall the same as or similar to second inner sidewall 25 and second outer sidewall 26 (shown in FIGS. 6-8 and described herein).

[65] At operation 112, an intermediate portion is formed between the first outer sidewall and the second inner sidewall of the motor housing. The forming of the intermediate portion may include formation of openings. In some embodiments, operation 112 is performed by an intermediate portion the same as or similar to intermediate portion 27 (shown in FIGS. 6-8 and described herein).

[66] At operation 1 14, at least one of the first or second cylindrical shell is machined or otherwise configured such that the first and second cylindrical shells have different axial lengths and such that a particular motor may fit within the motor housing. The motor may be coupled to one of the first or second cylindrical shell. In some embodiments, operation 114 is performed with a motor housing the same as or similar to motor housing 22 (shown in FIGS. 6-8 and described herein).

[67] At operation 116, at least one of the first or second cylindrical shell is machined or otherwise configured such that the first and second cylindrical shells have different radial lengths and such that the particular motor may fit within the motor housing. In some embodiments, operation 116 is performed with a motor housing the same as or similar to motor housing 22 (shown in FIGS. 6-8 and described herein).

[68] At operation 118, the motor is housed within the motor housing. The motor is configured to drive the crankshaft. In some embodiments, operation 1 18 is performed by a motor and a motor housing the same as or similar to motor 76 and motor housing 22 (shown in FIGS. 8A-8B and described herein).

[69] At operation 120, the motor housing is operative ly coupled to an outer or inner surface of the crankcase. The decision as to whether to couple to the outer surface or to the inner surface of the crankcase may be based on a size, shape, or dimensions of the crankcase, motor housing, and/or motor. In some embodiments, operation 120 is performed by a motor housing and a crankcase the same as or similar to motor housing 22 and crankcase 18a (shown in FIGS. 8A-8B and described herein). [70] At operation 122, a piston is reciprocated within the cylinder. In some embodiments, operation 122 is performed by a piston and a cylinder the same as or similar to piston 14a and cylinder 12a (shown in FIG. 1 and described herein).

[71] In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word "comprising" or "including" does not exclude the presence of elements or steps other than those listed in a claim. In a device claim enumerating several means, several of these means may be embodied by one and the same item of hardware. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. In any device claim enumerating several means, several of these means may be embodied by one and the same item of hardware. The mere fact that certain elements are recited in mutually different dependent claims does not indicate that these elements cannot be used in combination.

[72] Although the description provided above provides detail for the purpose of illustration based on what is currently considered to be the most practical and preferred embodiments, it is to be understood that such detail is solely for that purpose and that the disclosure is not limited to the expressly disclosed embodiments, but, on the contrary, is intended to cover modifications and equivalent arrangements that are within the spirit and scope of the appended claims. For example, it is to be understood that the present disclosure contemplates that, to the extent possible, one or more features of any embodiment can be combined with one or more features of any other embodiment.