Standby bearing for compressor

Abstract

There is provided a heat exchanger for heating, ventilation, air conditioning and refrigeration (HVACamp; a compressor for a compressor (R, R) system includes a compressor housing and a shaft configured to rotate within the compressor housing. The compressor also includes a main bearing disposed annularly around the shaft. The main bearing is configured to receive a flow of pressurized fluid and discharge the pressurized fluid toward the shaft. In addition, the compressor includes a backup bearing disposed annularly around the shaft. The backup bearing is configured to engage with the shaft during an operative interruption of the main bearing.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to and the benefit of U.S. Provisional Application No. 63 / 460,227, filed on April 18, 2023, entitled “BACKUP BEARINGS FOR COMPRESSOR,” and U.S. Provisional Application No. 63 / 443,921, filed on February 7, 2023, entitled “BEARING SYSTEM FOR HVAC&R SYSTEM,” each of which is hereby incorporated by reference in its entirety for all purposes. Background Art

[0002] This section is intended to introduce the reader to various aspects of technology that may be related to the various aspects of the present disclosure described below. It is believed that this discussion will help provide the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Therefore, it should be understood that these statements should be read in this light, and not as admissions of prior art.

[0003] Chiller systems, or vapor compression systems, utilize a working fluid (e.g., a refrigerant) that changes phase between vapor, liquid, or combinations thereof in response to exposure to varying temperatures and pressures within the chiller system's components. Chiller systems place the working fluid in heat exchange with a cooling fluid (e.g., water) and deliver the cooling fluid to the conditioning equipment and / or conditioned environment served by the chiller system. In such applications, the cooling fluid can be directed through downstream equipment, such as air handlers, to condition other fluids, such as the air within a building. Chiller systems may include a compressor configured to pressurize the working fluid and circulate it through the chiller system's working fluid circuit. In some applications, the compressor's shaft may be rotated by a motor to drive the compressor's impeller, thereby pressurizing the working fluid. Traditionally, compressors include bearings configured to facilitate rotation and support the load on the shaft. Unfortunately, in some cases, the bearings may malfunction during compressor operation, potentially adversely affecting the chiller system's operation and worsening its condition. Summary of the Invention

[0004] The following describes an overview of certain embodiments disclosed herein. It should be understood that these aspects are presented merely to provide the reader with a brief overview of these specific embodiments, and these aspects are not intended to limit the scope of the present disclosure. In fact, the present disclosure may encompass various aspects that may not be described below.

[0005] In one embodiment, a compressor for a heating, ventilation, air conditioning, and refrigeration (HVAC&R) system includes a compressor housing and a shaft configured to rotate within the compressor housing. The compressor also includes a main bearing disposed annularly around the shaft. The main bearing is configured to receive a flow of pressurized fluid and discharge the pressurized fluid toward the shaft. Additionally, the compressor includes a backup bearing disposed annularly around the shaft. The backup bearing is configured to engage the shaft during an operational interruption of the main bearing.

[0006] In another embodiment, a heating, ventilation, air conditioning, and refrigeration (HVAC&R) system includes a compressor having a compressor housing and a shaft configured to rotate within the compressor housing. The HVAC&R system further includes a first bearing disposed about the shaft. The first bearing is configured to receive a pressurized fluid and discharge the pressurized fluid toward the shaft. Additionally, the first bearing is configured to establish a first gap distance between the first bearing and the shaft during operation of the compressor. Additionally, the HVAC&R system includes a second bearing disposed about the shaft. The second bearing is configured to establish a second gap distance between the second bearing and the shaft during operation of the shaft. The first gap distance is less than the second gap distance. Additionally, the HVAC&R system includes a fluid supply system configured to direct the pressurized fluid to the main bearing.

[0007] In another embodiment, a bearing assembly for supporting a shaft of a compressor includes a main bearing disposed about the shaft's rotational axis. The main bearing is configured to discharge refrigerant inside the main bearing, and the main bearing is configured to establish a first clearance distance between the shaft and the main bearing during operation of the compressor. The bearing assembly further includes a backup bearing disposed about the shaft's rotational axis. The backup bearing is configured to establish a second clearance distance between the backup bearing and the shaft during operation of the compressor. The second clearance distance is greater than the first clearance distance. Furthermore, the bearing assembly includes a bearing housing configured to support the main bearing and the backup bearing. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Various aspects of the present disclosure may be better understood after reading the following detailed description and referring to the accompanying drawings, in which: Figure 1 is a perspective view of an embodiment of a building that may utilize a heating, ventilation, air conditioning, and refrigeration (HVAC&R) system in a commercial environment according to one aspect of the present disclosure; Figure 2 is a perspective view of an embodiment of a vapor compression system according to one aspect of the present disclosure; Figure 3 is a schematic diagram of an embodiment of a vapor compression system according to an aspect of the present disclosure; Figure 4is a schematic diagram of an embodiment of a vapor compression system according to an aspect of the present disclosure; Figure 5 is a cross-sectional side view of an embodiment of a compressor of a vapor compression system according to an aspect of the present disclosure, illustrating a bearing system of the compressor; Figure 6 is a cross-sectional side view of an embodiment of a portion of a compressor of a vapor compression system according to an aspect of the present disclosure showing a bearing assembly disposed about a shaft of the compressor; Figure 7 is a cross-sectional side view of an embodiment of a portion of a compressor of a vapor compression system according to an aspect of the present disclosure illustrating a bearing assembly disposed about a shaft of the compressor; and Figure 8 is an axial view of an embodiment of a bearing assembly for a compressor according to an aspect of the present disclosure. DETAILED DESCRIPTION

[0009] One or more specific embodiments will be described below. In order to provide a concise description of these embodiments, not all features of the actual implementation are described in the specification. It should be understood 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 developer's specific goals, such as consistency with system-related constraints and enterprise-related constraints, which may vary from one implementation to another. Moreover, it should be understood that such development work may be complex and time-consuming, but is a routine task of design, manufacturing, and production for those of ordinary skill having the benefit of this disclosure.

[0010] When introducing elements of various embodiments of the present disclosure, the articles "a," "an," and "the" are intended to mean that there are one or more of the elements. The terms "comprising," "including," and "having" are intended to be inclusive and mean that there may be additional elements other than the listed elements. Furthermore, it should be understood that references to "one embodiment" or "an embodiment" of the present disclosure are not intended to be interpreted as excluding the existence of additional embodiments that further incorporate the recited features.

[0011] As used herein, the terms "approximately," "substantially," and "substantially" are intended to convey that the value of the property being described may be within a relatively small range of that property value, as understood by one skilled in the art. For example, when a property value is described as being "approximately" equal to (or, for example, "substantially similar to") a given value, this is intended to mean that the property value may be within + / - 5%, + / - 4%, + / - 3%, + / - 2%, + / - 1%, or even closer to the given value. Similarly, when a given feature is described as being "substantially parallel" to another feature, "substantially perpendicular" to another feature, etc., this is intended to mean that the given feature has the described property within + / - 5%, + / - 4%, + / - 3%, + / - 2%, + / - 1%, or even closer, such as being parallel to another feature, being perpendicular to another feature, etc. Furthermore, it should be understood that mathematical terms such as "flat," "slope," "perpendicular," "parallel," and the like are intended to encompass characteristics of surfaces or elements as understood by one of ordinary skill in the relevant art and should not be interpreted as strictly as would be understood in the mathematical arts. For example, a "flat" surface is intended to encompass a surface that is machined, molded, or otherwise formed to be generally flat or smooth (within relevant tolerances) using techniques and tools available to one of ordinary skill in the art. Similarly, a surface having a "slope" is intended to encompass a surface that is machined, molded, or otherwise formed to be oriented at an angle (e.g., tilted) relative to a reference point using techniques and tools available to one of ordinary skill in the art.

[0012] Embodiments of the present disclosure relate to a heating, ventilation, air conditioning, and refrigeration (HVAC&R) system (e.g., a chiller) that includes a vapor compression system (e.g., a vapor compression circuit) with a compressor. During operation, the compressor pressurizes a working fluid within the vapor compression system and directs the working fluid to a condenser (e.g., a first heat exchanger), which cools and condenses the working fluid. The condensed working fluid can be directed to an expansion device, which reduces the pressure of the working fluid, thereby further cooling the working fluid. From the expansion device, the cooled working fluid can be directed to an evaporator (e.g., a second heat exchanger), where it is placed in heat exchange with a conditioning fluid (e.g., a cooling fluid) to cool the conditioning fluid. The conditioning fluid can be circulated between the evaporator and a structure, such as a building, where it is used to cool an air flow delivered to a conditioned space within the structure. In some embodiments, an air handling unit (AHU) of the HVAC&R system can receive the conditioning fluid from the vapor compression system and use it to cool the air flow delivered to the conditioned space. The conditioning fluid can then be returned to the evaporator for further cooling.

[0013] In some embodiments, a compressor may include an impeller configured to rotate to pressurize and direct a working fluid through a vapor compression system. For example, the impeller may be coupled to a shaft, and the shaft may be driven to rotate relative to the compressor's housing to effect rotation of the impeller relative to the housing. Typically, a compressor includes one or more bearings configured to facilitate rotation of the shaft relative to the compressor's housing. According to the present technology, a compressor includes one or more main bearings (e.g., a main bearing system) configured to utilize a pressurized fluid, such as a working fluid (e.g., refrigerant) circulating through the vapor compression system, to support the load of the compressor's shaft and lubricate the shaft's rotation within the compressor's housing. Specifically, the pressurized fluid may be directed through the one or more main bearings so that the pressurized fluid impinges on the shaft, thereby facilitating rotation of the shaft within the housing. In some circumstances, normal operation of the main bearings may be unexpectedly interrupted, in which case the shaft may no longer be adequately supported by the main bearings. In such circumstances, it may be desirable to suspend operation of the compressor in a controlled manner to limit wear and degradation of the compressor and its components, including the main bearings.

[0014] Thus, the present embodiment relates to a bearing system having a backup bearing configured to support a compressor shaft and enable rotation of the shaft in the event that operation of a main bearing (e.g., normal operation) is unexpectedly interrupted. The backup bearing can temporarily enable continued operation of the compressor (e.g., rotation of the shaft) during the operational interruption of the main bearing. Furthermore, the backup bearing can facilitate controlled deceleration of the shaft in response to the interruption of operation of the main bearing during compressor shutdown.

[0015] As mentioned above, the main bearings described herein are configured to utilize a pressurized fluid, such as a portion of a working fluid (e.g., refrigerant) circulated through a vapor compression system, to support the load of a compressor shaft and enable rotation of the shaft within the compressor's housing. The pressurized fluid can also serve as a lubricant. To this end, the bearing system includes one or more main bearings having porous bearing elements configured to receive the pressurized fluid. The pressurized fluid (e.g., a liquid) can be directed through the porous bearing elements and then contact the shaft within the housing. As the pressurized fluid is directed through and discharged from the porous bearing elements, it may vaporize or "flash" into a vapor or gas, which contacts the shaft and forms a hydrostatic film around it. Consequently, the pressurized fluid creates a gap (e.g., a void, a space, a first gap) between the shaft and the porous bearing elements, causing the shaft to remain suspended within the housing and away from the main bearings during operation of the compressor. In this way, the working fluid, which circulates through the vapor compression system to exchange heat with another fluid (e.g., a conditioning fluid supplied to the load), can also serve as a lubricant (e.g., a bearing fluid) to achieve desired operation of the compressor. In fact, the present embodiment enables the integration of the main bearing within the compressor without utilizing a separate dedicated lubricant (such as oil). Compared to conventional bearings, the disclosed embodiments of the bearing system can also be implemented at reduced costs (e.g., manufacturing costs, operating costs, maintenance costs).

[0016] Similar to the main bearing, a backup bearing may be disposed around the shaft, with a gap (e.g., a clearance, space, or a second gap) extending between the shaft and the backup bearing during operation of the compressor. In some embodiments, the second gap between the shaft and the backup bearing may be greater than the first gap between the shaft and the main bearing. That is, during operation of the compressor and the main bearing, the backup bearing does not contact the shaft. However, during an operational interruption of the main bearing, the main bearing may no longer adequately support the shaft. In other words, the main bearing may not levitate the shaft within the main bearing. In such circumstances, the shaft may contact the backup bearing, providing adequate support and enabling full rotation of the shaft within the housing, such as during a controlled shutdown of the compressor. In other words, the shaft may drop from its suspended position to contact the backup bearing, which provides a bearing interface against which the shaft can rotate. In this way, shaft rotation is not abruptly halted during an operational interruption of the main bearing, which could otherwise cause wear and degradation to the compressor. The backup bearing may be any suitable type of bearing, such as a mechanical bearing. In some embodiments, the backup bearing may include a roller bearing, a ball bearing, a sleeve bearing, a bushing bearing, a plain bearing, a journal bearing, a magnetic bearing, or any other suitable type of bearing.

[0017] Turning now to the accompanying drawings, Figure 1is a perspective view of an embodiment of a heating, ventilation, air conditioning, and refrigeration (HVAC&R) system 10 for use in a building 12 in a typical commercial environment. The HVAC&R system may include a boiler 16 for supplying a warm fluid to heat the building 12 and a vapor compression system 14 for supplying a cooled fluid to cool the building 12. The vapor compression system 14 (sometimes referred to as a chiller) may circulate a working fluid (e.g., a refrigerant) that is cooled by a cooling fluid (e.g., a liquid such as water) in a condenser of the vapor compression system 14 and heated by a conditioning fluid (e.g., a fluid such as water) in an evaporator of the vapor compression system 14. The cooling fluid may be provided by a cooling tower that cools the cooling fluid via, for example, ambient air. The conditioning fluid, cooled by the working fluid as described above, may be used to cool the air flow provided to the conditioned spaces of the building 12.

[0018] The HVAC&R system 10 may also include an air distribution system that circulates air through the building 12. The air distribution system may also include air return ducting 18, air supply ducting 20, and / or air handlers 22. In some embodiments, the air handlers 22 may include a heat exchanger that is connected to the boiler 16 and the vapor compression system 14 via ducting 24. Depending on the operating mode of the HVAC&R system 10, the heat exchanger in the air handlers 22 may receive heated liquid from the boiler 16 or a conditioning fluid (e.g., cooled liquid, such as water) from the vapor compression system 14. The HVAC&R system 10 is shown as having a separate air handler on each floor of the building 12, but in other embodiments, the HVAC&R system 10 may include air handlers 22 and / or other components that may be shared between floors.

[0019] Figure 2 and Figure 3 An embodiment of a vapor compression system 14 or chiller that can be used in an HVAC&R system 10 is shown. The vapor compression system 14 can circulate a working fluid through a circuit (e.g., a working fluid circuit, a refrigerant circuit) that begins with a compressor 32 (such as a centrifugal compressor). The circuit can also include a condenser 34, an expansion valve or device 36, and an evaporator 38. The vapor compression system 14 can further include a control panel 40 having an analog-to-digital (A / D) converter 42, a microprocessor 44, non-volatile memory 46, and / or an interface board 48.

[0020] Some examples of fluids that can be used as working fluids (e.g., refrigerants) in the vapor compression system 14 are: hydrofluorocarbon (HFC)-based working fluids, such as R-410A, R-407, R-134a, hydrofluoroolefins (HFOs); "natural" working fluids, such as ammonia (NH3), R-717, carbon dioxide (CO2), R-744; or hydrocarbon-based working fluids, water vapor, or any other suitable working fluid. Other possible working fluids include R-123, R-514A, R-1224yd, R-1233zd, R-134a, R-1228ze, R-1228yf, R-1311, R-32, and R-410A. In some embodiments, the vapor compression system 14 can be configured to efficiently utilize a working fluid having a normal boiling point of approximately 19 degrees Celsius (66 degrees Fahrenheit) at one atmosphere of pressure, also known as a low-pressure working fluid, as opposed to a medium-pressure working fluid (such as R-134a). As used herein, "normal boiling point" may refer to the boiling point temperature measured at one atmosphere of pressure.

[0021] In some embodiments, the vapor compression system 14 may utilize one or more of a variable speed drive (VSD) 52, a motor 50, the compressor 32, the condenser 34, the expansion valve or device 36, and / or the evaporator 38. The motor 50 may drive the compressor 32 during a normal operating mode and may be powered by the variable speed drive (VSD) 52. The VSD 52 receives alternating current (AC) power during a normal operating mode, wherein the AC power comprises a specific fixed line voltage and a fixed line frequency from an AC power source, and provides power having a variable voltage and frequency to the motor 50. In other embodiments, the motor 50 may be powered directly from an AC or direct current (DC) power source. The motor 50 may include any type of motor that can be powered by a VSD or directly from an AC or DC power source, such as a switched reluctance motor, an induction motor, an electronically commutated permanent magnet motor, or another suitable motor.

[0022] The compressor 32 compresses the working fluid vapor and delivers the vapor to the condenser 34 through the exhaust passage. In some embodiments, the compressor 32 may be a centrifugal compressor. The working fluid vapor delivered to the condenser 34 by the compressor 32 can transfer heat to the cooling fluid (e.g., water or air) in the condenser 34. Due to the heat transfer with the cooling fluid, the working fluid vapor can be condensed into working fluid liquid in the condenser 34. The liquid working fluid from the condenser 34 can flow to the evaporator 38 through the expansion device 36. Figure 3 In the illustrated embodiment, the condenser 34 is water-cooled and includes a tube bundle 54 connected to a cooling tower 56 that supplies cooling fluid to the condenser 34 .

[0023] The liquid working fluid delivered to the evaporator 38 may absorb heat from the conditioning fluid, which is then directed to the load 62 (eg, Figure 1 For example, the conditioning fluid may be cooled by the working fluid in the evaporator 38 and may then be cooled in the Figure 1 The liquid working fluid in the evaporator 38 may undergo a phase change from liquid working fluid to working fluid vapor. Figure 3 In the illustrated embodiment, the evaporator 38 can include a tube bundle 58 having a supply line 60S and a return line 60R connected to a cooling load 62. The conditioning fluid (e.g., water, ethylene glycol, calcium chloride brine, sodium chloride brine, or any other suitable fluid) for the evaporator 38 enters the evaporator 38 via the return line 60R and exits the evaporator 38 via the supply line 60S. The evaporator 38 can reduce the temperature of the conditioning fluid in the tube bundle 58 through heat transfer with the working fluid. The tube bundle 58 in the evaporator 38 can include multiple tubes and / or multiple tube bundles. In any case, the vapor working fluid exits the evaporator 38 and returns to the compressor 32 via the suction line to complete the cycle.

[0024] Figure 4 is a schematic diagram of an embodiment of a vapor compression system 14 having an intermediate loop 64 incorporated between the condenser 34 and the expansion device 36. The intermediate loop 64 may have an inlet line 68 directly fluidly connected to the condenser 34. In other embodiments, the inlet line 68 may be indirectly fluidly coupled to the condenser 34. Figure 4 In the illustrated embodiment, the inlet line 68 includes a first expansion device 66 positioned upstream of an intermediate vessel 70. In some embodiments, the intermediate vessel 70 may be a flash tank (e.g., a flash intercooler). In other embodiments, the intermediate vessel 70 may be configured as a "heat exchanger" or a "surface economizer." Figure 4In the illustrated embodiment, the intermediate vessel 70 serves as a flash tank, and the first expansion device 66 is configured to reduce the pressure of the liquid working fluid received from the condenser 34 (e.g., expand the liquid working fluid). During the expansion process, a portion of the liquid working fluid may vaporize, and thus, the intermediate vessel 70 may be used to separate the vapor working fluid from the liquid working fluid received from the first expansion device 66. Additionally, due to the pressure drop experienced by the liquid working fluid upon entering the intermediate vessel 70 (e.g., due to the rapid increase in volume experienced upon entering the intermediate vessel 70), the intermediate vessel 70 may provide further expansion of the liquid working fluid. The vapor working fluid in the intermediate vessel 70 may be drawn by the compressor 32 via a suction line 74 of the compressor 32. In other embodiments, the vapor working fluid in the intermediate vessel 70 may be drawn to an intermediate stage (e.g., other than the suction stage) of the compressor 32. Due to the expansion of the working fluid at the expansion device 66 and / or in the intermediate vessel 70, the liquid working fluid collected in the intermediate vessel 70 may be at a lower enthalpy than the liquid working fluid exiting the condenser 34. The liquid working fluid from the intermediate vessel 70 may then flow through line 72 and through the second expansion device 36 to the evaporator 38 .

[0025] According to this embodiment, the compressor 32 may be a centrifugal compressor (e.g., a hermetic compressor) having a suspended rotor or shaft. To this end, the vapor compression system 14 includes a bearing system having one or more main bearings configured to support the load of the shaft of the compressor 32. The bearing system is configured to direct a pressurized fluid (e.g., a liquid) through the main bearings, and the main bearings are configured to discharge the fluid toward and against the shaft to achieve suspension of the shaft within the compressor 32. Specifically, the main bearings include one or more porous bearing elements configured to receive the pressurized fluid and direct it toward the shaft within the housing of the compressor 32 (e.g., radially inward). In this manner, the bearing system can support the load on the shaft and enable rotation of the shaft within the housing of the compressor 32 during operation of the vapor compression system 14. As discussed herein, the pressurized fluid can be a working fluid (e.g., a refrigerant) circulated through the vapor compression system 14. Consequently, the vapor compression system 14 can support and rotate the shaft of the compressor 32 without utilizing a dedicated lubricant (such as oil). Further, the bearing system may be integrated with the vapor compression system 14 at a reduced cost compared to other existing bearing system designs. According to the present technique, in addition to the main bearings, the compressor 32 also includes one or more backup bearings, as described in further detail below.

[0026] Considering the above, Figure 5FIG3 is a cross-sectional side view of an embodiment of a compressor 32 including a bearing system 100 according to aspects of the present disclosure. The compressor 32 may include a housing 102 and a shaft 104 extending through the housing 102. The compressor 32 may also include an impeller 106 coupled to the shaft 104, such as via fasteners 108. During operation of the compressor 32, the shaft 104 may rotate (e.g., via operation of the motor 50) and cause the impeller 106 to rotate. The rotation of the impeller 106 may drive a working fluid (e.g., refrigerant) through a working fluid flow path 110 (e.g., from the evaporator 38, from the intermediate reservoir 70, or from a working fluid circuit) to draw the working fluid into the housing 102 via a suction inlet 112 and toward the impeller 106. The impeller 106 may transfer mechanical energy to the working fluid and discharge the working fluid to a diffuser passage 114 of the compressor 32. The working fluid may be directed from the diffuser passage 114 to a volute 116 of the compressor 32 , and from the volute 116 to a condenser (eg, condenser 34 ) to exchange heat with a fluid, such as a cooling fluid.

[0027] In the illustrated embodiment, the compressor 32 (e.g., the bearing system 100) includes a first main bearing 118 (e.g., a radial bearing, a hydrodynamic bearing, a porous bearing) and a second main bearing 120 (e.g., a radial bearing, a hydrodynamic bearing, a porous bearing) configured to control and / or adjust the position (e.g., radial position) of the shaft 104 relative to an axis 122 (e.g., an axis of rotation, a central axis) of the shaft 104. For example, the first and second main bearings 118, 120 may be disposed about the shaft 104 (e.g., annularly disposed about the shaft) and configured to support a load of the shaft 104 such that the shaft 104 is suspended within the first and second main bearings 118, 120. The first and second main bearings 118, 120 may also be configured to prevent movement of the shaft 104 transverse to the axis 122 (e.g., bending, radial movement, eccentric rotation). The compressor 32 (e.g., the bearing system 100) further includes a third main bearing 124 (e.g., a thrust bearing, an axial bearing, a bearing assembly, a porous bearing) configured to control and / or adjust the position (e.g., the axial position) of the shaft 104 along the axis 122. For example, the third bearing 124 can be configured to prevent or limit movement (e.g., translation) of the shaft 104 along the axis 122.

[0028] As mentioned above, the bearing system 100 is configured to direct a pressurized fluid to the main bearings of the bearing system 100, such as the first main bearing 118, the second main bearing 120, and / or the third main bearing 124. The pressurized fluid may be the same working fluid (e.g., a refrigerant) as the working fluid circulated through the vapor compression system 14 (e.g., the working fluid flow path 110) having the compressor 32. However, it should be understood that the pressurized fluid may be any suitable fluid, such as a refrigerant, a condensable vapor, or other fluid. In some embodiments, the first main bearing 118, the second main bearing 120, and / or the third main bearing 124 each include one or more porous elements 126 (e.g., shim portions) configured to direct the pressurized fluid therethrough. For example, the one or more porous elements 126 of the first and second main bearings 118, 120 may be configured to receive the pressurized fluid and direct it toward the shaft 104 to establish a high-pressure fluid film (e.g., a vapor film) around the shaft 104 between the first and second main bearings 118, 120 and the shaft 104. For example, the first and second main bearings 118, 120 can direct (e.g., discharge, spray) the pressurized fluid radially inward (e.g., toward the axial center of the bearings). In this manner, the pressurized fluid can levitate the shaft 104 from the first and second main bearings 118, 120, thereby enabling the desired rotation of the shaft 104 about the axis 122. One or more porous elements 126 of the third main bearing 124 can receive the pressurized fluid and direct it toward a collar 128 (e.g., a thrust collar) of the third main bearing 124. In this manner, the pressurized fluid can exert a force on the collar 128 and enable adjustable positioning of the shaft 104 along the axis 122.

[0029] The bearing system 100 includes a fluid supply system 130 configured to supply pressurized fluid to the main bearings (the first main bearing 118, the second main bearing 120, and / or the third main bearing 124) of the bearing system 100. For example, the fluid supply system 130 may direct the pressurized fluid to the housing 102 and, through the housing 102 of the compressor 32, to one or more bearing housings 132 (e.g., casings) containing the first main bearing 118, the second main bearing 120, and / or the third main bearing 124. In the illustrated embodiment, one bearing housing 132 is associated with the first main bearing 118, and another bearing housing 132 is associated with the second main bearing 120. Additional bearing housings 132 may be utilized with the third main bearing 124. In other embodiments, the second main bearing 120 and the third main bearing 124 may be housed together in a common bearing housing 132. The pressurized fluid may be directed through the bearing housings 132 to the corresponding porous element 126 retained within each bearing housing 132. It should be appreciated that the compressor 32 may include any suitable number or type (eg, radial, axial) of bearings incorporating the present technology, and the main bearings may be positioned at any suitable location within the casing 102 of the compressor 32 .

[0030] The compressor 32 (e.g., the bearing system 100) further includes one or more backup bearings 134 (e.g., second bearings) configured to support the shaft 104 and enable rotation thereof, such as during situations in which operation of the main bearings (e.g., the first main bearing 118 and / or the second main bearing 120) is unexpectedly (e.g., unexpectedly) interrupted and / or otherwise adversely affected. In some embodiments, each backup bearing 134 may be associated with and / or positioned adjacent to a corresponding main bearing (e.g., the first main bearing 118 or the second main bearing 120). In the illustrated embodiment, each backup bearing 134 is housed within a bearing housing 132 corresponding to the first bearing 118 or the second bearing 120, along with the first bearing 118 or the second bearing 120. That is, the first bearing assembly 136 of the bearing system 100 may include one of the bearing housings 132 that encloses the first main bearing 118 and one of the backup bearings 134. Similarly, the second bearing assembly 138 of the bearing system 100 may include another bearing housing 132 containing a second main bearing 120 and another backup bearing 134. In some embodiments, the second bearing assembly 138 may also include a third main bearing 124 supported by a corresponding bearing housing 132. In other embodiments, the backup bearings 134 may each be housed within a separate respective bearing housing 132 (e.g., a backup bearing housing).

[0031] Figure 6 FIG2 is a detailed cross-sectional side view of an embodiment of a portion of a compressor 32 including a bearing assembly 150 according to aspects of the present disclosure. For example, the bearing assembly 150 may be an embodiment of the first bearing assembly 136 or the second bearing assembly 138 discussed above. In other words, the bearing assembly 150 is a radial bearing assembly configured to support (e.g., suspend) the shaft 104 within the housing 102 of the compressor 32 to enable rotation of the shaft 104. The bearing assembly 150 includes a bearing housing 132 and a main bearing 152 (e.g., a first bearing, the first main bearing 118 or the second main bearing 120, a porous bearing) supported (e.g., retained) within the bearing housing 132. Thus, the main bearing 152 is disposed about the shaft 104 in a fixed position relative to the housing 102 of the compressor 32 (e.g., circumferentially, annularly, and annularly). The main bearing 152 is configured to receive pressurized working fluid (e.g., refrigerant) from the fluid supply system 130 and discharge the pressurized working fluid from the porous element 126 of the main bearing 152. In this manner, the pressurized working fluid may impact the shaft 104 , causing the shaft 104 to be lifted from the main bearing 152 and suspended within the bearing assembly 150 .

[0032] The bearing assembly 150 further includes an embodiment of a backup bearing 134 (e.g., a second bearing) disposed within the bearing housing 132. In some embodiments, when the bearing assembly 150 is mounted within the compressor 32 and around the shaft 104, the backup bearing 134 can be positioned outboard of the main bearing 152 (e.g., relative to the longitudinal center or lengthwise center of the shaft 104, relative to the stator of the motor 50). As discussed above, the backup bearing 134 is supported by (e.g., coupled to, mounted to) the bearing housing 132 and disposed around (e.g., circumferentially, annularly around) the shaft 104. Thus, during interruptions in operation of the main bearing 152, the backup bearing 134 can engage and support the shaft 104 and enable continued rotation of the shaft 104 within the bearing assembly 150. For example, in some circumstances, such as during an operational interruption of the fluid supply system 130, the pressure of the working fluid supplied to and / or discharged from the porous element 126 of the main bearing 152 may drop. As another example, the supply of pressurized fluid to the main bearing 152 may be unexpectedly interrupted, such as due to an interruption in the power supply to the HVAC&R system 10 (e.g., the fluid supply system 130). In other cases, mechanical degradation of the main bearing 152 may result in a disruption in the operability of the main bearing 152. Consequently, the main bearing 152 may no longer operate to lift or suspend the shaft 104 within the bearing assembly 150 via the pressurized working fluid. In such cases, the shaft 104, no longer suspended by the pressurized working fluid, may contact the inner surface 153 (e.g., the inner annular surface) of the main bearing 152. However, without pressurized fluid directed through the main bearing 152, the inner surface 153 of the main bearing 152 may not adequately support the shaft 104 and / or enable rotation thereof. In such cases, the shaft 104 may also contact the backup bearing 134. Thus, the backup bearing 134 may at least partially support the load of the shaft 104. Furthermore, the backup bearing 134 may provide a bearing interface between the backup bearing 134 and the shaft 104, achieving reduced friction therebetween. In this manner, the backup bearing 134 may enable continued rotation of the shaft 104. For example, the backup bearing 134 may enable controlled deceleration of the shaft 104, such as during shutdown of the compressor 32. In this manner, the backup bearing 134 may mitigate wear and degradation to the compressor 32 and components of the compressor 32 (e.g., the motor) that may otherwise be caused during interrupted operation of the main bearing 152.

[0033] As mentioned above, during operation of the main bearing 152, the backup bearing 134 does not engage (e.g., contact) the shaft 104. For example, the backup bearing 134 can be configured to establish a gap (e.g., a second gap, a backup gap) between the shaft 104 and the backup bearing 134 (e.g., the inner annular surface of the backup bearing 134). The gap between the shaft 104 and the backup bearing 134 can be greater than the gap (e.g., the first gap, the main gap) established between the main bearing 152 and the shaft 104 during operation of the main bearing 152 (e.g., the porous element and / or the inner surface of the main bearing 152). That is, during operation of the main bearing 152, the main bearing 152 can suspend the shaft 104 a first distance 154 extending (e.g., radially) from the inner surface of the main bearing 152. Additionally, during operation of the main bearing 152, the backup bearing 134 can be positioned to maintain a gap having a second distance 156 extending (e.g., radially) between the inner surface of the backup bearing 134 and the shaft 104. In other words, backup bearing 134 may be concentric with shaft 104, and the inner diameter of backup bearing 134 may be greater than the radius of shaft 104 at the axial position of backup bearing 134 along shaft 104 by a second distance 156. In some embodiments, second distance 156 may be greater than first distance 154 by any suitable amount, such as approximately 3 millimeters (mm), 2 mm, 1 mm, 0.5 mm, 0.25 mm, 0.1 mm, 0.01 mm, or any other suitable distance. Additionally or alternatively, second distance 156 may be greater than first distance 154 by 1.1 times, 2 times, 5 times, 10 times, or any other suitable multiple. While second distance 156 is greater than first distance 154, second distance 156 can be selected (e.g., via the configuration of backup bearing 134, shaft 104, or both) such that backup bearing 134 is configured to achieve adequate or proper alignment of shaft 104 (e.g., along or relative to axis 122) during conditions in which main bearing 152 is not operating and backup bearing 134 contacts and supports shaft 104. In this manner, backup bearing 134 can mitigate wear and degradation of compressor 32 during interrupted operation of main bearing 152, as well as controlled operation and / or shutdown. Additionally, according to the present technique, the tolerance (e.g., manufacturing tolerance) of the inner diameter of backup bearing 134 can be greater than the tolerance (e.g., manufacturing tolerance) of the inner diameter of main bearing 152, for example, to accommodate thermal expansion of backup bearing 134 and / or shaft 104 during operation of compressor 32.

[0034] In the illustrated embodiment, the diameter of the shaft 104 varies along the length of the shaft 104 (e.g., along the axis 122). For example, a first diameter 158 of the shaft 104 along a first portion 160 of the shaft 104 is greater than a second diameter 162 along a second portion 164 of the shaft 104. The main bearing 152 can be disposed (e.g., in an annular shape) around the first portion 160, and the backup bearing 134 can be disposed (e.g., in an annular shape) around the second portion 164. Thus, the inner diameter of the main bearing 152 can be sized by the sum of the first diameter 158 and twice the first distance 154. Additionally, the inner diameter of the backup bearing 134 can be sized by the sum of the second diameter 162 and twice the second distance 156.

[0035] Figure 7 FIG2 is a detailed cross-sectional view of another embodiment of a portion of a compressor 32 according to aspects of the present disclosure, illustrating a bearing assembly 150 and a sleeve 166 disposed about the shaft 104. The sleeve 166 may be coupled to or integrally formed with the shaft 104 along at least a portion of the shaft 104, such as a portion of the shaft 104 about which the main bearing 152 and / or the bearing assembly 150 are disposed. In some embodiments, the sleeve 166 may have a low-friction surface (e.g., on an outer diameter) to achieve improved performance of the main bearing 152. The sleeve 166 may additionally or alternatively include a conductive feature, such as metal bristles (e.g., a brush, a carbon brush) positioned on the outer diameter of the sleeve 166. The conductive feature may contact the main bearing 152 to establish electrical continuity between the shaft 104 with the sleeve 166 and the main bearing 152, thereby indicating contact therebetween. When the shaft 104 is lifted from the main bearing 152 during operation of the main bearing 152, the sleeve 166 does not contact the main bearing 152, which may disrupt electrical continuity therebetween, thereby indicating separation of the main bearing 152 from the shaft 104. Based on the detection of electrical continuity, electrical discontinuity, and / or electrical resistance between the shaft 104 and the main bearing 152, operation of the compressor 32 may be adjusted or controlled. For example, detecting electrical continuity between the main bearing 152 and the shaft 104 may indicate a disruption in operability of the main bearing 152, and thereby contact between the shaft 104 and the backup bearing 134. Based on this detection, the HVAC&R system 10 may adjust operation of the compressor 32, for example, by initiating a shutdown sequence of the compressor 32 (e.g., the motor 50).

[0036] In the illustrated embodiment, the diameter of the sleeve 166 remains generally constant along the portion of the shaft 104 about which the bearing assembly 150 is disposed. As similarly discussed above, the inner diameter of the backup bearing 134 can be larger than the inner diameter of the main bearing 152 (e.g., approximately 3 millimeters (mm), 2 mm, 1 mm, 0.5 mm, 0.25 mm, 0.1 mm, 0.01 mm, or any other suitable distance). In other words, the difference between the first distance 154 (e.g., the clearance of the main bearing 152) and the second distance 156 (e.g., the clearance of the backup bearing 134) can be half the difference between the inner diameter of the backup bearing 134 and the inner diameter of the main bearing 152.

[0037] Figure 8 FIG2 is an axial view of an embodiment of a bearing assembly 150 including a main bearing 152 and a backup bearing 134. As discussed above, the bearing assembly 150 includes a bearing housing 132 that can accommodate both the main bearing 152 and the backup bearing 134. For example, the backup bearing 134 can be radially disposed within the bearing housing 132 (e.g., relative to the axis 122) and retained within the housing 132 via fasteners 170 (e.g., mechanical fasteners, screws, bolts, etc.). The fasteners 170 can extend through one or more rigid plates 172 (e.g., retainers, extensions) and into the bearing housing 132. The rigid plates 172 can extend radially relative to the axis 122 and can overlap (e.g., radially overlap) the backup bearing 134 and the bearing housing 132. Thus, the rigid plates 172 can retain the backup bearing 134 within the bearing housing 132 and can prevent movement of the backup bearing 132 relative to the bearing housing 132 and along the axis 122.

[0038] In some embodiments, the backup bearing 134 may be a mechanical bearing. For example, the backup bearing 134 may be a ball bearing or roller bearing having balls or rollers 174 (e.g., bearing elements) configured to roll (e.g., translate, rotate, or slide) along an inner wall 176 of the backup bearing 134. In this manner, friction between the shaft 104 and the backup bearing 134 may be reduced. In other embodiments, the backup bearing 134 may be a sleeve bearing, a bushing bearing, a journal bearing, a sliding contact bearing, a magnetic bearing, a hydrostatic bearing, a hydrodynamic bearing with an independent fluid supply system, or any other suitable bearing type. For example, the backup bearing 134 may be a sleeve having an inner surface (e.g., a diameter surface, a sliding surface, a bearing surface) made of a relatively soft material (e.g., bronze) configured to contact the shaft 104 and absorb impact or force from the shaft 104.

[0039] Although only certain features and embodiments have been shown and described, numerous modifications and changes may occur to those skilled in the art without materially departing from the novel teachings and advantages of the subject matter recited in the claims, such as changes in the size, dimensions, structure, shape and proportions of various components, parameter values ​​(such as temperature and pressure), mounting arrangements, use of materials, color, orientation, etc. The order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments. It should be understood, therefore, that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the present disclosure.

[0040] Furthermore, in an effort to provide a concise description of exemplary embodiments, not all features of an actual implementation may be described, such as those not relevant to the presently contemplated best mode or those not relevant to enablement. It should be understood that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions may be made. Such development work may be complex and time-consuming, but for those of ordinary skill having the benefit of this disclosure, these are routine tasks of design, fabrication, and production without undue experimentation.

[0041] The technology presented and claimed herein refers to and applies to substantial objects and specific examples of practical nature that improve the technical field of the invention in a demonstrable manner and are therefore not abstract, intangible, or purely theoretical. Further, if any claim appended to the end of this specification contains one or more elements that are expressed as "means for [performing] [the function] ..." or "steps for [performing] [the function] ...", it is intended that such elements will be interpreted in accordance with 35 USC 112(f). However, for any claim containing elements specified in any other manner, it is intended that such elements will not be interpreted in accordance with 35 USC 112(f).

Claims

1. A compressor for a heating, ventilation, air conditioning, and refrigeration (HVAC&R) system, comprising: compressor housing; a shaft configured to rotate within the compressor housing; a main bearing annularly disposed about the shaft, wherein the main bearing is configured to receive a flow of pressurized fluid and discharge the pressurized fluid toward the shaft; as well as A backup bearing is annularly disposed about the shaft, wherein the backup bearing is configured to engage the shaft during an interruption in the operation of the main bearing.

2. The compressor of claim 1 , wherein the main bearing is configured to establish a first gap distance between the main bearing and the shaft during operation of the main bearing, the backup bearing is disposed around the shaft at a second gap distance between the backup bearing and the shaft, and the second gap distance is greater than the first gap distance.

3. The compressor of claim 1, comprising a bearing housing disposed within the compressor housing, wherein the main bearing and the backup bearing are supported by the bearing housing.

4. The compressor according to claim 1, wherein the backup bearing is a roller bearing or a ball bearing. The compressor of claim 1 , wherein the backup bearing is a sliding bearing. 6 . The compressor of claim 1 , wherein the main bearing is configured to support the shaft during non-operation of the compressor.

7. The compressor according to claim 1, comprising: a first bearing assembly, wherein the first bearing assembly includes the main bearing and the backup bearing; and a second bearing assembly, the second bearing assembly comprising an additional main bearing and an additional backup bearing, wherein the additional main bearing and the additional backup bearing are arranged in an annular manner around the shaft, The first bearing assembly is disposed at a first end of the shaft, and the second bearing assembly is disposed around a second end of the shaft opposite the first end.

8. The compressor of claim 1, wherein the backup bearing is positioned outboard of the main bearing relative to a longitudinal center of the shaft.

9. The compressor of claim 1, wherein the main bearing and the backup bearing are concentric.

10. The compressor of claim 1, wherein the compressor is configured to circulate a working fluid through a working fluid circuit of the HVAC&R system, and the main bearing is configured to receive a portion of the working fluid as the flow of pressurized fluid.

11. A heating, ventilation, air conditioning, and refrigeration (HVAC&R) system comprising: A compressor, comprising: compressor housing; a shaft configured to rotate within the compressor housing; a first bearing disposed about the shaft, wherein the first bearing is configured to receive a pressurized fluid and discharge the pressurized fluid toward the shaft, and the first bearing is configured to establish a first clearance distance between the first bearing and the shaft during operation of the compressor; and a second bearing disposed about the shaft, wherein the second bearing is configured to establish a second gap distance between the second bearing and the shaft during operation of the shaft, wherein the first gap distance is less than the second gap distance; and A fluid supply system is configured to direct the pressurized fluid to the first bearing.

12. The HVAC&R system of claim 11, wherein the second bearing is configured to contact and support the shaft in response to interruption of operation of the first bearing.

13. The HVAC&R system of claim 11, wherein the first bearing and the second bearing are disposed at ends of the shaft, and the first bearing is disposed between the second bearing and a longitudinal center of the shaft along the longitudinal axis of the shaft.

14. The HVAC&R system of claim 11, wherein the first bearing includes a first inner diameter and the second bearing includes a second inner diameter that is larger than the first inner diameter.

15. The HVAC&R system of claim 11, wherein the second bearing is a roller bearing, a ball bearing, or a plain bearing.

16. The HVAC&R system of claim 11, wherein the fluid supply system is configured to direct refrigerant of the HVAC&R system to the first bearing as the pressurized fluid.

17. A bearing assembly for supporting a shaft of a compressor, the bearing assembly comprising: a main bearing disposed about a rotational axis of the shaft, wherein the main bearing is configured to discharge refrigerant inside the main bearing and the main bearing is configured to establish a first clearance distance between the shaft and the main bearing during operation of the compressor; a backup bearing disposed about the rotational axis of the shaft, wherein the backup bearing is configured to surround the shaft at a second gap distance between the backup bearing and the shaft during operation of the compressor, wherein the second gap distance is greater than the first gap distance; as well as A bearing housing is configured to support the main bearing and the backup bearing.

18. The bearing assembly of claim 17, wherein the backup bearing is configured to contact the shaft in response to interruption of operability of the main bearing during operation of the compressor.

19. The bearing assembly of claim 17, wherein the main bearing is configured to support the shaft during non-operation of the compressor such that the backup bearing does not contact the shaft during non-operation of the compressor.

20. The bearing assembly of claim 17, wherein the backup bearing comprises a roller bearing or a bronze plain bearing.

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