Patent ID: 12188471

DETAILED DESCRIPTION

One or more specific embodiments of the present disclosure will be described below. These described embodiments are only examples of the presently disclosed techniques. Additionally, in an effort to provide a concise description of these embodiments, all features of an actual implementation may not be described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure.

A heating, ventilation, air conditioning, and/or refrigeration (HVAC&R) system may include a vapor compression system having a compressor (e.g., a screw compressor) that is configured to circulate a fluid through a circuit. The compressor may include one or more rotors mounted on one or more shafts and disposed inside a rotor housing. Bearings (e.g., ball bearings, journal bearings, thrust bearings) engage the one or more shafts to facilitate rotation of the rotors during operation of the compressor. To reduce wear on the bearings and increase efficiency of the compressor, a lubricant (e.g., oil) is directed into the rotor housing. The lubricant may provide cooling, reduce friction between moving components, and/or seal portions of the compressor. Typically, the lubricant is provided from a lubricant source and is directed into an intake portion of the rotor housing via ports extending into the rotor housing. The lubricant provided to the intake portion flows through the rotor housing to lubricate various components of the compressor and then flows toward a discharge portion of the rotor housing. In existing systems, lubricant may mix with fluid flowing through the compressor, which may reduce an efficiency of the HVAC&R system. Accordingly, embodiments of the present disclosure are configured to reduce an amount of lubricant that may flow through a compression chamber of the compressor by directing the lubricant through passageways extending through the rotors and toward various components of the compressor (e.g., bearings).

Operation of the compressor may generate a pressure differential between the compressor inlet (e.g., suction side) and the compressor outlet (e.g., discharge side), which may impose an axial force on the rotors of the compressor (e.g., a force applied in an axial direction from the discharge port toward the suction port). In some embodiments, a bearing, such as a thrust bearing, may be radially coupled to a shaft of a rotor of the compressor and may function to block axial movement (e.g., axial vibrations) of the rotor. In some cases, the axial force imparted on the thrust bearing during operation of the compressor may cause the thrust bearing to incur wear. In some cases, a balance piston may be used to apply a counter-force to the rotor that is opposite in direction to the axial force. Unfortunately, balance pistons may increase the costs and complexity of the compressor. Therefore, to improve the operational life of the thrust bearing, embodiments of the present disclosure may direct a lubricant (e.g., oil) toward an end of the rotor (e.g., an end proximate the intake portion or suction side of the compressor) so that the lubricant may apply the counter-force to the rotor and increase an operating life of the thrust bearing. Additionally or alternatively, the lubricant may be directed through passageways extending through the rotor toward the thrust bearing to provide the counter-force to the rotor of the screw compressor with the lubricant. In still further embodiments, the passageway may be configured to receive the lubricant from the thrust bearing and direct the lubricant toward the discharge portion or the intake portion of the compressor.

In a typical screw compressor, lubricant is provided to both the intake portion and the discharge portion of the rotor housing via a lubricant source. For example, conduits external to the rotor housing may supply the lubricant from the lubricant source to lubricant ports of the rotor housing. As should be understood by those of skill in the art, screw compressors may generate pulses or vibrations during operation, which may increase wear incurred by conduits that direct the lubricant from the lubricant source to the compressor. Thus, it may be desirable to reduce or limit an amount of conduits that are utilized to direct lubricant to the rotor housing. In some embodiments of the present disclosure, the compressor is configured to receive lubricant via a port in one of the intake portion or the discharge portion. The lubricant may flow from the intake portion toward the discharge portion, or vice versa, through passageways formed within and extending through the rotor in order to provide a counter-force, as well as provide cooling, lubrication, and/or sealing to various components of the compressor. The inclusion of internal passageways within the rotors to transfer lubricant may reduce the usage of external conduits and/or other lubricant ports to transfer lubricant to and through the compressor. Because fewer ports and conduits are utilized, wear on various components incurred from pulses or vibrations may be reduced. As such, including the lubricant passageway within one or more rotors of the compressor may increase efficiency of the compressor, decrease wear on thrust bearings, and/or reduce maintenance costs of the compressor.

Turning now to the drawings,FIG.1illustrates a cross-sectional view of an embodiment of a compressor10that may be used in a vapor compression system. To facilitate discussion, the compressor10and its components may be described with reference to a longitudinal axis or direction14, a vertical axis or direction16, and a lateral axis or direction18. It should be noted that the vertical axis16and the lateral axis18extend in radial directions relative to the longitudinal axis14. The compressor10includes a compressor housing20that contains working components (e.g., bearings) of the compressor10. As described in greater detail herein, the compressor housing20may include an intake portion22(e.g., suction side), a compression portion24(e.g., compression chamber), and a discharge portion26(e.g., discharge side).

In some embodiments, the intake portion22includes an intake port28configured to receive a fluid from a fluid circuit having the compressor. The fluid (e.g., a gaseous refrigerant) from the vapor compression system may be drawn into the intake port28to enter a compression chamber30of the compressor portion24via the intake port28. The compressor10includes a male rotor32and a female rotor34, which may rotate about a first axis35and a second axis37, respectively. The male rotor32and the female rotor34each extend from at least the intake portion22to the discharge portion26in a direction substantially parallel to the longitudinal axis14, such that the first axis35and the second axis37also extend parallel to the longitudinal axis14. The male rotor32includes one or more protruding lobes36disposed circumferentially about the male rotor32. Similarly, the female rotor34includes one or more corresponding grooves38disposed circumferentially about the female rotor34that are configured to receive and/or engage with the lobes36of the male rotor32.

The lobes36of the male rotor32may mesh with the corresponding grooves38on the female rotor34to form a series of gaps40between the rotors32,34. The gaps40may continuously compress fluid (e.g., the refrigerant) entering the compressor10via the intake port28and may direct compressed fluid toward a discharge port42of the discharge portion24. For example, during operation of the compressor10, the gaps40may continuously reduce in volume as the rotors32,34rotate and thereby compress the fluid along the length of the rotors32,34from the intake port28to the discharge port42. The compressed fluid (e.g., vapor refrigerant) may exit the compression chamber30through the discharge port42to flow out of the compressor10.

During operation of the compressor10, an axial force48may be imposed on a first shaft50of the male rotor32and/or on a second shaft52of the female rotor34. The axial force48may be generated due to a pressure differential between a first end portion54of the rotors32,34(e.g., near the intake port28) and a second end portion56of the rotors32,34(e.g., near the discharge port42). For example, a first pressure of the fluid acting on components within the compressor10at the intake port28may be substantially less (e.g., 2 times less, 20 times less, or more) than a second pressure of the fluid acting on the components within the compressor10at the discharge port42. Accordingly, a difference between the second pressure and the first pressure may generate the axial force48, which may be applied to the rotors32,34in a direction57toward the intake portion22of the compressor housing20. In some embodiments, the male rotor32may be configured to drive (e.g., rotate) the female rotor34(e.g., rotation of the shaft of the female rotor34is not driven by a motor or external drive). For example, the lobes36(e.g., helical lobes) of the male rotor32may engage with the grooves38(e.g., helical grooves) of the female rotor34, such that rotation of the male rotor32may induce rotation of the female rotor34. The female rotor34may resist rotation (e.g., due to the pressure differential between the end portions54,56of the rotors32,34, inertia, etc.) and may thus impose an axial thrust59on the male rotor32. The axial thrust59may act in the direction57and may therefore increase a magnitude of the axial force48imposed on the male rotor32.

In some embodiments, the axial force48may be transmitted to one or more bearings, such as a thrust bearing58, which is radially disposed about the first shaft50of the male rotor32and/or the second shaft52of the female rotor34. While the illustrated embodiment ofFIG.1shows the compressor10having one thrust bearing58associated with the male rotor32and one thrust bearing58associated with the female rotor34, it should be noted that the compressor10may include two, three, four, five, six, seven, eight, nine, ten, or more thrust bearings58disposed about (e.g., adjacent to one another) one or both of the rotors32,34. The thrust bearing58may counter-act a substantial portion of the axial force48, such that the axial force48does not induce damage to certain compressor10components. However, application of the axial force48may reduce an operational or useful life of the thrust bearing58due to excess forces imposed on the thrust bearing58. In some embodiments, the thrust bearing58may be an axial contact ball bearing, a four-point ball bearing, a tilt pad thrust bearing, or another suitable bearing configured to at least partially counter-act the axial force48.

In some embodiments, a force application device, such as a balance piston may be disposed within a portion of the compressor housing20(e.g., the intake portion22) and may be configured to impose a regulating force60(e.g., a counter-force) on the first shaft50, the second shaft52, or both. However, in other embodiments, the compressor10may be a sleeve bearing compressor that includes a tilt pad thrust bearing, and thus, may not include a balance piston. Typically, the thrust bearing58(e.g., a tilt pad thrust bearing) of a sleeve bearing compressor supports a substantial amount of a load applied by the axial force48. In some embodiments, lubricant63may be utilized to reduce a portion of the axial force48applied to the thrust bearing58. For example, the lubricant63may be directed toward an end31of the male rotor32and an end33of the female rotor34to apply the regulating force60to the rotors32and34, and thus reduce a portion of the axial force48applied to the thrust bearing58. That is, the lubricant63may apply pressure to the ends31and/or33of the rotors32and/or34proximate the intake portion22. The pressure of the lubricant63(e.g., the regulating force60) is configured to counteract the axial force48, which may increase an operational or useful life of the thrust bearing58.

The lubricant63may be directed into the compressor housing20at the intake portion22of the compressor10. For example, in the illustrated embodiment, the compressor housing20includes a lubricant inlet port74that is configured to receive the lubricant63from a conduit78fluidly coupled to a lubricant supply76. From the lubricant inlet port74, the lubricant63is directed toward a lubricant passageway that is located within the intake portion22of the compressor housing20. The lubricant passageway may direct the lubricant63toward sleeve bearings61that are disposed about the male rotor32and/or the female rotor34of the compressor10within the intake portion22. As will be appreciated, the sleeve bearings61are configured to block radial movement (e.g., movement along the vertical axis16and/or the lateral axis18) of the male rotor32and/or the female rotor34in the compressor housing20. In some embodiments, the compressor10may additionally or alternatively include one or more mechanical bearings65(e.g., ball bearings, roller bearings, journal bearings) that are configured to block radial movement of the male rotor32and/or the female rotor34in the compressor housing20. The sleeve bearings61, the mechanical bearings65, and/or other suitable bearings of the compressor10may receive the lubricant63from the lubricant passageway during operation to reduce friction between the sleeve bearings61, the mechanical bearings65, and/or other suitable bearings of the compressor10and the rotors32and34as the rotors32and34rotate to compress the fluid.

In accordance with present embodiments, the lubricant passageway is also fluidly coupled to a passageway66formed in (e.g., internally formed within) at least one of the male rotor32and the female rotor34. The passageway66(e.g., internal passageway) provides a flow path for the lubricant63received by fluid passageway at the intake portion22of the compressor10. As shown in the illustrated embodiment ofFIG.1, the male rotor32and the female rotor34each include the passageway66formed in a body portion68of the male rotor32and a body portion68of the female rotor34, and the passageways66extend along the first axis35and second axis37. In this way, the passageways66provide a flow path for the lubricant63(e.g., oil) from the intake portion22to the discharge portion26of the compressor10in a single flow direction. In operation, lubricant63received by the intake portion22(e.g., that is not directed to the sleeves61and/or other bearings positioned within, or positioned proximate to, the intake portion22) may flow through the passageways66extending through the rotors32,34toward the discharge portion26of the compressor10. Within the discharge portion26, the lubricant63may be directed toward the sleeves61and/or the mechanical bearings65positioned within, or positioned proximate to, the discharge portion26. In this way, lubricant63may be utilized to reduce friction between components within the discharge portion26and the male rotor32and/or the female rotor34. In some embodiments, the passageway66includes multiple outlets that direct the lubricant63toward components of the compressor10, such that the components receive a sufficient amount of the lubricant63to enable desired or improved operation of the compressor10. Used and/or excess lubricant63may then be directed out of the compressor10via a lubricant drain port67positioned proximate the discharge portion26.

While the illustrated embodiment includes the lubricant inlet port74positioned at the intake portion22and the lubricant drain port67positioned at the discharge portion26, it should be appreciated that other variations of the compressor10may also include rotors32,34with the passageway66formed therein for transfer of lubricant63from the intake portion22to the discharge portion26and vice versa. For example, lubricant inlet ports74may be included proximate to both the intake portion22and the discharge portion26or may be included proximate to the discharge portion26, but not proximate to the intake portion22. Similarly, in certain embodiments, the lubricant drain port67may be positioned proximate one or both of the intake portion22and the discharge portion26. Lubricant63received by the intake portion22or the discharge portion26may then be transferred to the opposite end of the compressor10via the passageway66formed in and extending along the rotors32,34in order to supply the lubricant63to the various components of the compressor10. It will be appreciated that the use of lubricant inlet ports74in one of the intake portion22and the discharge portion26of the compressor housing20may enable a reduction in the amount of conduits78supplying the lubricant63to the compressor10. As noted above, reducing the amount or number of conduits78may reduce wear caused by forces that are associated with vibration of the compressor10during operation.

Directing the lubricant63through the passageways66may also increase the operational efficiency of the compressor10. For example, the lubricant63may flow through the intake portion22and into the passageway66extending through and along the male rotor32and/or the female rotor34instead of flowing into the compression chamber30. Enabling the lubricant63to bypass the compression chamber30(e.g., by directing the lubricant63through the passageway66) increases the efficiency of the HVAC&R system by reducing mixing of the lubricant63with fluid or other working fluid in the compression chamber30. With less or no lubricant63mixed with the fluid within the compressor10, and therefore within other portions of the vapor compression system, more efficient operation of the vapor compression system is enabled. For example, features or operations typically included with the compressor10separate lubricant63from fluid may not be utilized or may be utilized to a lesser degree.

FIG.2is a section view of an embodiment of the male rotor32, which may be utilized in the compressor10ofFIG.1, in accordance with an aspect of the present disclosure. The male rotor32includes the body portion68and one or more of the lobes36(e.g., protruding lobes) disposed circumferentially about the male rotor32. The lobes36may extend radially outward from the first axis35(e.g., central axis) of the body portion68toward the compression portion24of the compressor10. As set forth above, the lobes36on the male rotor32may mesh with corresponding grooves38of the female rotor34(FIG.3) to form the gaps40between the rotors32and34. The gaps40may continuously compress fluid (e.g., refrigerant) within the compression portion24of the compressor10as the rotors32and34rotate about the axes35and37, respectively.

The male rotor32also includes the passageway66formed within (e.g., internally within) the body portion68, and the passageway66extends along the first axis35(e.g., rotational axis) of the male rotor32. The passageway66includes at least one channel80extending through the body portion68of the male rotor32. The passageway66is configured to fluidly couple the intake portion22and the discharge portion26of the compressor10with respect to a flow of the lubricant63. In particular, the passageway66enables the lubricant63to flow between the intake portion22and the discharge portion26of the compressor10. Additionally, in an installed and operational configuration of the male rotor32within the compressor housing20, the passageway66is not directly fluidly coupled to the compression portion24. As a result, an amount of the lubricant63flowing directly into the compression portion24is reduced.

The passageway66may include an axial portion82and one or more radial portions84. In some embodiments, the axial portion82of the passageway66may extend partially through the body portion68along the first axis35of the male rotor32. In the illustrated embodiment ofFIG.2, the axial portion82extends from the end31of the male rotor32to a portion86of the male rotor32between the compression portion24and a discharge end88of the male rotor32. The end31may be disposed proximate to and/or within the intake portion22of the compressor housing20, and the discharge end88may be disposed proximate to and/or within the discharge portion26of the compressor housing20. In some embodiments, the axial portion82may extend from the discharge end88toward a portion of the male rotor32between the compression portion24and the end31of the male rotor32. Additionally, in some embodiments, the axial portion82may have a constant diameter (e.g., having a substantially consistent diameter measurement within typical tolerances for forming or measuring such features) extending from the end31to the portion86. However, in other embodiments, the axial portion82has a variable diameter between the end31and the portion86. Further, the axial portion82may be coaxial with the first axis35(e.g., central axis) of the male rotor32, which may maintain or balance a center of mass of the male rotor32proximate to the first axis35(i.e., the axis of rotation of the male rotor32). As such, a torque utilized to rotate the male rotor32to a desired angular velocity may be reduced and/or maintained at a level that is similar or substantially equal to that of an embodiment of the male rotor32without the passageway66. In other embodiments, the axial portion82may be offset from the first axis35of the body portion68of the male rotor32. Additionally or alternatively, the body portion68and/or the lobes36of the male rotor32may have a semi-hollow structure (e.g., a plurality of cavities or webs within the body portion68and/or the lobes36). The passageway66may form at least a portion of the semi-hollow structure of the body portion68to enable the lubricant63to flow between the end31and the discharge end88of the male rotor32.

The one or more radial portions84of the passageway66may be fluidly coupled to the axial portion82and may extend radially outward from the axial portion82through an exterior surface90of the male rotor32. The one or more radial portions84may include one or more openings92that direct the lubricant63from the axial portion82toward the sleeves61, the one or more mechanical bearings65, and/or other suitable components of the compressor10. The one or more openings92may be positioned proximate to and/or within the discharge portion26of the compressor housing20, such that the one or more radial portions84direct the lubricant63toward the discharge portion26, and ultimately out of the compressor10via the lubricant drain port67. While the illustrated embodiment ofFIG.2shows the radial portions84disposed at a single axial position of the male rotor32with respect to the first axis35, it should be noted that, in other embodiments, the one or more radial portions84may be positioned at any suitable position along the first axis35of the male rotor32.

In some embodiments, the one or more radial portions84have a smaller diameter than the diameter of the axial portion82of the passageway66. The various dimensions of the passageway66may be configured to maintain a generally uniform flow rate of the lubricant63through the male rotor32. In such embodiments, a cumulative cross-sectional area of the one or more radial portions84may be substantially equal to a cross-sectional area of the axial portion82of the passageway66. In some embodiments, the one or more radial portions84may be spaced or arrayed evenly about the external surface90of the male rotor32. For example, a first radial portion may extend radially outward from the first axis35at a first angular position, and a second radial portion (e.g., adjacent to the first radial portion) may be angularly offset from the first radial portion by a target amount or angular dimension (e.g., 20 degrees). Further, a third radial portion (e.g., adjacent to the second radial portion) may be angularly offset from the second radial portion by the target amount or angular dimension (e.g., 20 degrees). In other words, adjacent radial portions of the one or more radial portions84may be angularly offset from one another by the target amount (e.g., 20 degrees), such that the one or more openings92are uniformly distributed about a circumference of the male rotor32. In other embodiments, the one or more radial portions84may not include a uniform angular offset from one another, such that the corresponding one or more openings92are unevenly spaced about the circumference of the male rotor32. In still further embodiments, the one or more radial portions84may be both radially and axially offset from one another. For example, the one or more radial portions84may be positioned at different axial locations along the body portion68with respect to the first axis35to direct the lubricant63toward different components (e.g., the sleeves61and/or the mechanical bearings65) positioned at different axial positions within the compressor housing20.

FIG.3is a section view of an embodiment of the female rotor34, which may be utilized with the compressor10ofFIG.1. As shown in the illustrated embodiment, the female rotor34includes a second body portion94with the grooves38disposed circumferentially about the female rotor34. The grooves38may mesh with corresponding lobes36of the male rotor32to form the series of gaps40between the female rotor34and the male rotor32. During operation, the gaps40may continuously compress fluid within the compression portion24of the compressor10as the rotors32and34rotate about the axes35and37, respectively.

Similar to the male rotor32, the female rotor34includes a second passageway98(e.g., passageway66) extending along the second axis37(e.g., central axis, rotational axis) of the female rotor34. The second passageway98may include at least one channel99extending through (e.g., internally within) the second body portion94of the female rotor34. The second passageway98is also configured to fluidly couple the intake portion22and the discharge portion26of the compressor10with respect to the flow of the lubricant63. Accordingly, the lubricant63(e.g., oil) may flow between the intake portion22and the discharge portion26of the compressor10without entering the compression portion24. To this end, in an installed and operational configuration of the female rotor34, the second passageway98is not directly fluidly coupled to the compression portion24, such that an amount of the lubricant63flowing directly into the compression portion24is reduced.

The second passageway98may include a second axial portion100extending through the entire second body portion94of the female rotor34with respect to the second axis37. For example, the second passageway98may extend from the end33of the female rotor34to a second discharge end104of the female rotor34. The end33may be disposed proximate to and/or within the intake portion22of the compressor10in an installed configuration, and the second discharge end104may be disposed proximate to and/or within the discharge portion26of the compressor10. In some embodiments, the second axial portion100of the female rotor34may have a constant diameter extending from the end33to the second discharge end104. In other embodiments, the second axial portion100has a variable diameter between the end33and the second discharge end104. Further, the second axial portion100may be coaxial with the second axis37of the female rotor34, which may maintain or balance a center of mass of the female rotor34proximate to the second axis37(i.e., the axis of rotation of the female rotor34). As such, a torque utilized to rotate the female rotor34to a desired angular velocity may be reduced and/or maintained at a level that is similar or substantially equal to an embodiment of the female rotor34without the second passageway98.

In some embodiments, the second passageway98includes one or more second radial portions106. The one or more second radial portions106of the second passageway98may be fluidly coupled to the second axial portion100and may extend radially outward from the second axial portion100through a second exterior surface108of the second body portion94. The one or more second radial portions106may include corresponding radial openings110that direct lubricant63from the second axial portion100toward the sleeves61, the mechanical bearings65, and/or other suitable components of the compressor10. The one or more second radial portions106may be disposed in the discharge portion26of the compressor housing20, such that the one or more second radial portions106of the second passageway98fluidly couple the second passageway98to the discharge portion26of the compressor10. While the illustrated embodiment ofFIG.3shows the one or more second radial portions106positioned proximate to the second discharge end104of the female rotor34, it should be noted that, in other embodiments, the one or more second radial portions106may be positioned at any suitable position along the second axis37of the female rotor34. In some embodiments, both the one or more second radial portions106and the second axial portion100are configured to connect the second passageway98to the discharge portion26of the compressor housing20. That is, the lubricant63may flow into a first area of the discharge portion26via the one or more second radial portions106, and the lubricant63may flow into a second area of the discharge portion26via an outlet111of the second axial portion100. The first and second areas of the discharge portion26may both include the components (e.g., the sleeves61and/or the mechanical bearings65) of the compressor10that receive and utilize the lubricant63. In other embodiments, the second axial portion100may not extend through the entire length of the second body portion94of the female rotor34. As such, the lubricant63may be directed toward the discharge portion26via the one or more second radial portions106.

FIG.4is a cross-sectional view of an embodiment of the compressor10, illustrating the male rotor32ofFIG.2and the female rotor34ofFIG.3. As shown in the illustrated embodiment, the compressor10includes lubricant flow paths that direct the lubricant63from the discharge portion26to the intake portion22of the compressor housing20.

As discussed above, the axial force48may be imposed on the first shaft50of the male rotor32and/or the second shaft52of the female rotor34during operation of the compressor10. The axial force48may be generated due to a pressure differential between the ends31,33of the rotors32,34(e.g., near the intake port28) and the discharge ends88,104of the rotors32,34(e.g., near the discharge port42). In some embodiments, the axial force48imposed on the rotors32,34may be transmitted to the thrust bearing58, which is disposed radially about at least a portion of the first shaft50of the male rotor32. In some embodiments, the compressor10may include thrust bearings58disposed radially about at least a portion of both the first shaft50of the male rotor32and the second shaft52of the female rotor34(e.g., as shown inFIG.4). The thrust bearing58may counter-act a substantial portion of the axial force48, such that the axial force48does not strain or cause stress to certain compressor10components. However, the axial force48may reduce an operational or useful life of the thrust bearing58. As shown in the illustrated embodiment ofFIG.4, the thrust bearing58includes an axial contact ball bearing and/or a four-point ball bearing configured to at least partially counter-act the axial force48.

In some embodiments, a force application device116, such as a balance piston, is disposed within a portion of the compressor housing20(e.g., proximate to the intake portion22) and is configured to impose the regulating force60(e.g., a counter-force) on the first shaft50, the second shaft52, or both. As such, in some embodiments, the compressor10may not utilize the lubricant63(e.g., oil) to provide the regulating force60in a direction opposite the axial force48on the rotors32and/or34, as described above with respect toFIG.1.

As set forth above, in some embodiments, the lubricant inlet ports74may direct the lubricant63toward the discharge portion26of the compressor10in addition to, or in lieu of, the intake portion22. For example, the lubricant63within the discharge portion26may be directed toward various components of the compressor10, such as the thrust bearing58and/or mechanical bearings65. Excess lubricant63and/or used lubricant63from the discharge portion26may flow into the passageway66(e.g., first passageway) of the male rotor32and/or the passageway98(e.g., second passageway) of the female rotor34toward the intake portion22of the compressor housing20. The intake portion22may receive the lubricant63from the passageways66,98and direct the lubricant63toward various components (e.g., mechanical bearings65) of the compressor10to reduce friction between the components and the rotors32,34. Positioning the lubricant inlet ports74at the discharge portion26of the compressor housing20instead of at the intake portion22may reduce an amount or number of the conduits78used to direct the lubricant63into the compressor10. Reducing the amount or number of conduits78may reduce maintenance on the compressor10by reducing an amount of components subjected to stress and/or strain caused by vibration of the compressor10during operation.

FIG.5is a cross-sectional view of an embodiment of the compressor10that may be utilized in a vapor compression system. As shown in the illustrated embodiment, the compressor10may include a dual pass configuration for directing the lubricant63toward various components of the compressor10. As similarly described above, the compressor housing20includes the intake portion22and the discharge portion26fluidly coupled to one another via the first passageway66and the second passageway98extending through the male rotor32and the female rotor34, respectively. The first passageway66extends along the first axis35of the male rotor32from the end31to the portion86of the male rotor32proximate to the first discharge end88of the male rotor32. The second passageway98extends along the second axis37of the female rotor34from the end33of the female rotor34to the second discharge end104of the female rotor34. In some embodiments, the discharge portion26is fluidly separated into a first discharge portion118(e.g., a first lubricant section of the discharge portion26) that surrounds and/or is otherwise proximate to the first discharge end88of the male rotor32and a second discharge portion120(e.g., a second lubricant section of the discharge portion26) that surrounds and/or is otherwise proximate to the second discharge end104of the female rotor34. In some embodiments, a barrier122(e.g., a plate) may be disposed between the first discharge portion118and the second discharge portion120, such that the lubricant63is blocked from flowing between the first and second discharge portions118,120.

In the illustrated embodiment, the compressor housing20includes the lubricant inlet port74that is configured to direct the lubricant63into the compressor housing20at the second discharge portion120. The lubricant63within the second discharge portion120may be configured to lubricate various components (e.g., the thrust bearing58and/or the mechanical bearings65) of the compressor10positioned within the second discharge portion120. The second discharge portion120may direct excess and/or used lubricant63into the second passageway98of the female rotor34and toward the intake portion22. The lubricant63received by the intake portion22via the second passageway98may then lubricate various components (e.g., the mechanical bearings65) of the compressor10within the intake portion22. In some embodiments, a second barrier128(e.g., a plate) may be disposed within the intake portion22and may include a channel130configured to enable flow of the lubricant63from an area of the intake portion22axially aligned with the female rotor34to an area of the intake portion22axially aligned with the male rotor32. In this way, lubricant63received by the intake portion22via the second passageway98may be directed toward the first passageway66. A cross-sectional area of the channel130may be adjusted (e.g., via a control system, an actuator, etc.) to control the flow of the lubricant63between the second passageway98and the first passageway66. In any case, the first passageway66may receive the lubricant63supplied to the intake portion22via the second passageway98and may direct the lubricant63toward the first discharge portion118. The first discharge portion118may then direct the lubricant63toward various components (e.g., the thrust bearing58and/or the mechanical bearings65) of the compressor10positioned within the first discharge portion118before directing the lubricant63out of the compressor housing20(e.g., via the lubricant drain port67).

In other embodiments, the lubricant inlet port74may direct the lubricant63toward the first discharge portion118instead of the second discharge portion120, such that the lubricant63flows into the first discharge portion118from the lubricant supply76, from the first discharge portion118to the intake portion22via the first passageway66, from the intake portion22toward the second passageway98, and from the second passageway98toward the second discharge portion120. In still further embodiments, the lubricant inlet port74may direct the lubricant63into the intake portion22, as discussed above with reference toFIG.1. In such embodiments, the second barrier128may be sealed (e.g., the channel130is sealed), and the barrier122may have a second channel132to enable lubricant63flow between the first discharge portion118and the second discharge portion120. Thus, the lubricant63may initially flow into the intake portion22and may follow a dual-pass flow path as generally described above.

FIG.6is a cross-sectional view of another embodiment of the compressor10. As discussed above, the force application device116may include a balance piston140that may be disposed within the compressor housing20(e.g., proximate to the intake portion22) and configured to impose a portion of or substantially all of the regulating force60(e.g., counter-force) on the first shaft50, the second shaft52, or both. For example, the balance piston140may be disposed within a cylinder142(e.g., a sleeve, a chamber or cavity formed within the compressor housing20), such that the cylinder142is divided into a first chamber144and a second chamber146. The first chamber144may be in fluid communication with the lubricant inlet74and configured to receive a flow of the lubricant63from the lubricant supply76. The second chamber146may be in fluid communication with the compression chamber30of the compressor10. In some embodiments, a sealing component of the balance piston140may form a fluidic seal between the first chamber144and the second chamber146, such that fluid (e.g., the lubricant63) is substantially blocked from flowing between the first and second chambers144,146. In other embodiments, a small quantity of lubricant63may be configured to flow past the balance piston140, such that the lubricant63may lubricate internal components of the compressor10(e.g., the mechanical bearings65, the shafts,50,52, the rotors32,34). For example, in certain embodiments, an orifice (e.g., a weep hole) formed in the balance piston140may enable lubricant63to flow from the first chamber144to the second chamber146. The lubricant63may be configured to subsequently flow from the second chamber146toward any of the aforementioned compressor components. In any case, the lubricant63may be used to pressurize the first chamber144(e.g., relative to the second chamber146) to generate a pressure differential across the balance piston140. As such, the generated pressure differential may enable the balance piston140to apply the counterforce60to counteract some of or substantially all of the axial force48.

In some embodiments, lubricant63within the first chamber144may contact the end31of the male rotor32. The channel130between the first chamber144and a corresponding chamber152of the female rotor34may enable lubricant63to flow toward and contact the end33of the female rotor34. Accordingly, in accordance with the techniques discussed above, the lubricant63may apply a portion of the regulating force60to the shafts50and52that may supplement the portion of the regulating force60applied to the shafts50and/or52by the balance piston140. That is, the lubricant63may apply pressure to the ends31and/or33of the rotors32and/or34to counteract some of or substantially all of the axial force48. As such, the balance piston140and/or the lubricant63directed toward the ends31and33of the male rotor32and/or the female rotor34may reduce the axial force48applied to the thrust bearing58and, thus, may enhance an operational or useful life of the thrust bearing58. It should be understood that, in some embodiments, the lubricant63may not be directed toward (e.g., contact) the end31of the male rotor32and/or the end33of the female rotor34.

In the illustrated embodiment, the compressor10includes lubricant flow paths (e.g., the passageways66,98) that may direct the lubricant63from the intake portion22to the discharge portion26of the compressor housing20. For example, the first passageway66formed in the male rotor32may be in fluid communication with the first chamber144(e.g., a high pressure chamber) of the balance piston140. As such, the first passageway66may receive lubricant63(e.g., high pressure lubricant) from the first chamber144and may direct the lubricant63along the interior of the male rotor32toward the discharge portion26of the compressor housing20. The lubricant63may be discharged (e.g., via the radial portions84) from the first passageway66at various locations along the compressor housing20(e.g., at first, second, and third locations154,156,158) to lubricate various components (e.g., the mechanical bearings65) of the compressor10. In some embodiments, lubricant63from the first passageway66may discharge into the first discharge portion118and may subsequently be directed into the second discharge portion120(e.g., via the channel132). In other embodiments, lubricant63within the first discharge portion118may be directed into the compression chamber30(e.g., near an upstream end of the compression chamber30), into a suction port of the compressor10(e.g., the intake port28), or toward any other suitable region of the compressor10.

As noted above, in some embodiments, lubricant63may flow through the channel130from the first chamber144of the balance piston140to the chamber152located near the end33of the female rotor34. As such, lubricant63may sequentially flow from the first chamber144into the chamber152, into the second passageway98, and through the second passageway98(e.g., in the direction14) from the intake portion22toward the discharge portion26of the compressor10. Similar to the male rotor32discussed above, it should be understood that the female rotor34may be configured to discharge lubricant63at a variety of locations along the compressor housing20to facilitate lubrication of certain compressor components. Lubricant63may discharge from the second passageway98into the second discharge portion120or to any other suitable region (e.g., the intake port28, the compression chamber30) of the compressor10.

In certain embodiments, the channel130may be omitted from the compressor10. In such embodiments, the lubricant63may be configured to flow, from the first chamber144, into and through the first passage66(e.g., in the direction14), into the first discharge portion118, into and through the second passage98(e.g., in the direction57), and into the chamber152. That is, the lubricant63may follow a dual-pass flow path through the male and female rotors32,34as generally described above. Indeed, it should be appreciated that the lubricant63may be directed through any of the aforementioned lubricant flow passages in multitudinous configurations. The lubricant63may drain from the chamber152to another suitable location of the compressor10, such as, for example, the intake port28, the compression chamber30, or the lubricant supply76.

As set forth above, embodiments of the rotors having the lubricant passageways disclosed herein may provide one or more technical effects useful in improving the performance of vapor compression systems. For example, embodiments of the present disclosure are directed toward improved compressor rotors that may increase a compression efficiency of fluid by reducing or removing lubricant within a compression chamber of the compressor. Instead, the lubricant is directed between an intake portion of the compressor and a discharge portion of the compressor through the passageways extending internally through one or more rotors of the compressor. Further, the compressor may include a reduced number of lubricant conduits (e.g., external conduits) that supply the lubricant to the compressor, which may reduce maintenance time and/or costs that may be incurred due to stress or wear on such conduits during compressor operation. In any case, the lubricant may be directed between the intake portion and the discharge portion of the compressor via the passageways extending through the rotors and toward one or more bearings and/or other components of the compressor without mixing with fluid compressed by the compressor. In some embodiments, the lubricant may be further directed toward an end of the one or more rotors of the compressor to apply a counter-force to the one or more rotors in order to reduce wear on thrust bearings of the compressor.

While only certain features and embodiments have been illustrated and described, many modifications and changes may occur to those skilled in the art (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters (e.g., temperatures, pressures, etc.), mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter recited in the claims. The order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the disclosure.

Furthermore, in an effort to provide a concise description of the exemplary embodiments, all features of an actual implementation may not have been described (i.e., those unrelated to the presently contemplated best mode, or those unrelated to enablement). It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation specific decisions may be made. Such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure, without undue experimentation.