Linear compressor and planar spring assembly

Abstract

A linear compressor (300) or a sealing system, the linear compressor (300) comprising a housing (308), a piston (316), a drive coil (366), an inner back iron assembly (352), and a flat spring assembly (500). The housing (308) comprises a cylinder assembly (310), which defines a compartment (312) in an axial direction. The piston (316) is slidably accommodated in the compartment (312) of the cylinder assembly (310). The inner back iron assembly (352) is positioned in the drive coil (366). The flat spring assembly (500) is mounted to the inner back iron assembly (352). The flat spring assembly (500) comprises a first flat spring (510); a second flat spring (510), which is axially spaced apart from the first flat spring (510); and a polymer shim layer (540A, 540B), which is arranged between at least part of the first flat spring (510) and the second flat spring (510). A spacer plug (530A, 530B) disposed between the first planar spring (510) and the second planar spring (510), wherein the polymer shim layer (540A, 540B) is sandwiched between the spacer plug (530A, 530B) and the first planar spring (510). The linear compressor (300) provided with the polymer shim layer (540A, 540B) can reduce or mitigate the effects of fretting fatigue at the flat spring assembly (500). The spacer plug (530A, 530B) in combination with the polymer shim layer (540A, 540B), distributes mechanical loads more evenly across the planar springs (510). This prevents localized stress concentrations that could lead to premature material fatigue or deformation, ensuring more stable and reliable long term operation of the compressor.

Description

Linear compressor and flat spring assembly Technical Field

[0001] The present subject matter generally relates to linear compressors, such as those used in refrigeration appliances. Background Art

[0002] Certain refrigeration appliances include a sealed system for cooling the freezer compartment of the appliance. This sealed system typically includes a compressor that generates compressed refrigerant during operation. The compressed refrigerant flows to an evaporator, where heat exchange occurs between the freezer compartments and the refrigerant cools the freezer compartments and the food items contained therein.

[0003] Recently, certain refrigeration appliances have included linear compressors for compressing refrigerant. Linear compressors typically include a piston and a drive coil. The drive coil receives an electric current, which generates a force that causes the piston to slide forward and backward within a compartment. During the piston's movement within the compartment, the piston compresses the refrigerant. One or more spring assemblies (e.g., planar spring assemblies) can be used to support one or more parts of the compressor (such as an iron assembly) and help transmit or inhibit the reciprocating motion of the piston.

[0004] Typically, a spring assembly for a linear compressor includes a plurality of discrete planar springs that can be stacked axially to work together to absorb or transfer the energy of axial motion (e.g., at a piston). Specifically, the discrete planar springs can be connected together so that the planar springs are axially compressed or otherwise held stationary relative to the planar spring assembly. However, one of the potential problems with such an arrangement is the generation of fretting fatigue. For example, stress or friction at the connection point between two planar springs can generate surface cracks in the planar springs, leading to premature fracture or failure. In some cases, a planar spring can lose up to 80% of its predicted strength due to fretting fatigue during use.

[0005] Therefore, there is a need for an improved linear compressor. Specifically, providing a linear compressor or assembly would be beneficial in reducing or alleviating the effects of fretting fatigue, for example, at a planar spring assembly.

[0006] Summary of the Invention

[0007] Various aspects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.

[0008] In one exemplary aspect of the present disclosure, a linear compressor for an electrical appliance is provided. The linear compressor may include a housing, a piston, a drive coil, an inner back iron assembly, and a planar spring assembly. The housing may include a cylinder assembly defining a compartment in an axial direction. The piston may be slidably received within the compartment of the cylinder assembly. The inner back iron assembly may be positioned within the drive coil. The planar spring assembly may be mounted to the inner back iron assembly. The planar spring assembly may include a first planar spring, a second planar spring axially spaced from the first planar spring, and a polymer shim layer disposed between at least a portion of the first planar spring and the second planar spring.

[0009] In another exemplary aspect of the present disclosure, a sealing system for an electrical appliance is provided. The sealing system may include a linear compressor, a housing, a condenser, and an evaporator. The linear compressor may define an axial direction and include a housing, a piston, a drive coil, an inner back iron assembly, and a planar spring assembly. The housing may include a cylinder assembly defining a compartment along the axial direction. The piston may be slidably received within the compartment of the cylinder assembly. The inner back iron assembly may be positioned within the drive coil. The planar spring assembly may be mounted to the inner back iron assembly. The planar spring assembly may include a first planar spring, a second planar spring axially spaced from the first planar spring, and a polymer gasket layer disposed between at least a portion of the first planar spring and the second planar spring. The housing may define an internal volume surrounding the linear compressor and containing lubricating oil. The condenser may be in fluid communication downstream of the linear compressor to receive compressed refrigerant therefrom. The evaporator may be in fluid communication upstream of the linear compressor to direct expanded refrigerant thereto.

[0010] These and other features, aspects and advantages of the present invention will be better understood with reference to the following description and appended claims.The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present invention and, together with the description, serve to explain the principles of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] A full and enabling disclosure of the invention, including the best mode thereof, to one skilled in the art is set forth in the specification with reference to the accompanying drawings.

[0012] FIG. 1 is a front view of a refrigeration appliance according to an exemplary embodiment of the present disclosure.

[0013] 2 is a schematic diagram of certain components of the exemplary refrigeration appliance of FIG. 1 with an optional oil cooling circuit in which a linear compressor may operate.

[0014] FIG3 provides a cross-sectional view of an exemplary linear compressor according to an exemplary embodiment of the present disclosure.

[0015] 4 provides a cross-sectional view of the exemplary linear compressor of FIG. 3 , illustrating a flow path according to an exemplary embodiment of the present disclosure.

[0016] FIG5 provides a perspective view of a planar spring assembly of a refrigeration appliance according to an exemplary embodiment of the present disclosure.

[0017] FIG. 6 provides an exploded perspective view of the exemplary planar spring assembly of FIG. 5 .

[0018] FIG. 7 provides an enlarged perspective view of a portion of the example planar spring assembly of FIG. 5 . DETAILED DESCRIPTION

[0019] Reference will now be made in detail to embodiments of the present invention, wherein one or more examples of these embodiments are illustrated in the accompanying drawings. Each example is provided by way of explanation rather than limitation of the present invention. In fact, it will be apparent to those skilled in the art that various modifications and variations may be made to the present invention without departing from the scope of the present invention. For example, a feature shown or described as part of one embodiment may be used in conjunction with another embodiment to provide yet another embodiment. Therefore, the present invention is intended to encompass such modifications and variations within the scope of the appended claims and their equivalents.

[0020] As used herein, the terms "first," "second," and "third" may be used interchangeably to distinguish one component from another and are not intended to indicate the position or importance of individual components. The terms "include" and "comprising" are intended to be inclusive, and are included in a manner similar to the term "comprising." Similarly, the term "or" is generally intended to be inclusive (e.g., "A or B" is intended to mean "A or B or both"). In addition, herein and throughout the specification and claims, range limitations may be combined or interchanged. Unless the context or language indicates otherwise, these ranges are identified and include all subranges contained therein. For example, all ranges disclosed herein include endpoints, and the endpoints are independently combinable with each other. Unless the context clearly states otherwise, the singular forms "a," "an," and "the" include multiple referents.

[0021] As used herein throughout the specification and claims, approximate language may be used to modify any quantitative representation that may vary without resulting in a change in the basic function to which it is associated. Thus, a value modified by one or more terms (such as "substantially," "about," "approximately," and "substantially") is not limited to the precise value specified. In at least some cases, approximate language may correspond to the precision of an instrument used to measure a value, or the precision of a method or machine used to construct or manufacture a component or system. For example, approximate language may refer to being within a 10% margin (e.g., a value included within 10% greater than or less than a specified value). In this regard, for example, when used in the context of an angle or direction, such terms are included within 10% greater than or less than a specified angle or direction (e.g., "substantially perpendicular" includes forming an angle of up to 10 degrees with the perpendicular direction V in any direction (such as, clockwise or counterclockwise)).

[0022] As used herein, the word "exemplary" means "serving as an example, instance, or illustration." Furthermore, references to "an embodiment" or "one embodiment" do not necessarily refer to the same embodiment, although they may. Any embodiment described herein as "exemplary" or "an embodiment" is not necessarily to be construed as being preferred or advantageous over other embodiments. Furthermore, each example is provided by way of explanation of the invention and not as a limitation thereof. Indeed, it will be apparent to those skilled in the art that various modifications and variations can be made to the invention without departing from the scope of the invention. For example, features shown or described as part of one embodiment may be used in conjunction with another embodiment to provide yet another embodiment. Accordingly, the present invention is intended to cover such modifications and variations as fall within the scope of the appended claims and their equivalents.

[0023] As used herein, the terms “first,” “second,” and “third” may be used interchangeably to distinguish one component from another and are not intended to denote the position or importance of individual components.

[0024] Turning now to the accompanying drawings, FIG1 shows a refrigeration appliance 10 incorporating a sealed refrigeration system 60 ( FIG2 ). It should be understood that the term “refrigeration appliance” as used herein is used in a general sense to encompass any type of refrigeration appliance, such as a freezer, a refrigerator / freezer combination, and any type or model of conventional refrigerator. Furthermore, it should be understood that the present disclosure is not limited to use in refrigeration appliances. Therefore, the present subject matter may be used for any other suitable purpose, such as vapor compression within an air conditioning unit or air compression within an air compressor.

[0025] In the illustrated exemplary embodiment shown in FIG1 , refrigeration appliance 10 is depicted as an upright refrigerator having a cabinet or housing 12 defining a plurality of internal refrigerated storage compartments. Specifically, refrigeration appliance 10 includes an upper fresh food compartment 14 having a door 16 and a lower freezer compartment 18 having an upper drawer 20 and a lower drawer 22. Drawers 20 and 22 are "pull-out" drawers because they can be manually moved into and out of freezer compartment 18 via a suitable sliding mechanism.

[0026] 2 provides a schematic diagram of certain components of the refrigeration appliance 10 , including the sealed refrigeration system 60 in the refrigeration appliance 10 . Specifically, FIG. 2 provides an alternative oil cooling circuit with the sealed refrigeration system 60 having a linear compressor 64 .

[0027] The mechanical compartment of the refrigeration appliance 10 may contain components for performing a known vapor compression cycle for cooling air. This includes a compressor 64, a condenser 66, an expansion device 68, and an evaporator 70, all connected in series and charged with refrigerant. As will be appreciated by those skilled in the art, the refrigeration system 60 may include additional components (e.g., at least one additional evaporator, compressor, expansion device, or condenser). For example, the refrigeration system 60 may include two evaporators.

[0028] Within the refrigeration system 60, refrigerant typically flows into a compressor 64, which operates to increase the pressure of the refrigerant. This compression of the refrigerant increases its temperature, which is then reduced by passing the refrigerant through a condenser 66. Within the condenser 66, heat exchange with the surrounding air occurs to cool the refrigerant. A condenser fan 72 is used to draw air through the condenser 66 to provide forced convection for more rapid and efficient heat exchange between the refrigerant within the condenser 66 and the surrounding air. Therefore, as will be appreciated by those skilled in the art, increasing the air flow through the condenser 66 can improve the efficiency of the condenser 66, for example, by improving the cooling of the refrigerant contained therein.

[0029] An expansion device (e.g., a valve, capillary tube, or other restrictive device) 68 receives refrigerant from the condenser 66. From the expansion device 68, the refrigerant enters the evaporator 70. Upon exiting the expansion device 68 and entering the evaporator 70, the refrigerant's pressure decreases. Due to the pressure drop or phase change in the refrigerant, the evaporator 70 becomes cooler relative to the compartments 14 and 18 of the refrigeration appliance 10. Consequently, cooled air is generated, cooling the compartments 14 and 18 of the refrigeration appliance 10. Thus, the evaporator 70 is a heat exchanger that transfers heat from the air passing through the evaporator 70 to the refrigerant flowing through the evaporator 70.

[0030] In summary, the vapor compression cycle components in the refrigeration circuit, associated fans, and associated compartments are sometimes referred to as a sealed refrigeration system, which is operable to force cold air through compartments 14 and 18 ( FIG. 1 ). The refrigeration system 60 shown in FIG. 2 is provided as an example only. Therefore, other configurations using refrigeration systems are also within the scope of the present disclosure.

[0031] In some embodiments, an oil cooling circuit 200 with a refrigeration system 60 is shown according to an exemplary embodiment of the present disclosure. The compressor 64 of the refrigeration system 60 may include or be disposed within a housing 302 ( FIG. 3 ) that also contains lubricating oil therein. The lubricating oil may assist in reducing friction between sliding or moving parts of the compressor 64 during operation. For example, when a piston slides within a cylinder to compress refrigerant, the lubricating oil may reduce friction between the piston and the cylinder of the compressor 64, as discussed in more detail below.

[0032] During operation of the compressor 64, the temperature of the lubricating oil may increase. Therefore, in an optional embodiment, an oil cooling circuit 200 is provided to assist in removing heat from the lubricating oil.

[0033] In the illustrated embodiment of FIG2 , the oil cooling circuit 200 includes a heat exchanger 210 spaced apart from at least a portion of the compressor 64. A lubricating oil conduit 220 extends between the compressor 64 and the heat exchanger 210. Lubricating oil from the compressor 64 may flow to the heat exchanger 210 via the lubricating oil conduit 220. As shown in FIG2 , the lubricating oil conduit 220 may include a supply conduit 222 and a return conduit 224. The supply conduit 222 extends between the compressor 64 and the heat exchanger 210 and is configured to direct lubricating oil from the compressor 64 to the heat exchanger 210. Conversely, the return conduit 224 extends between the heat exchanger 210 and the compressor 64 and is configured to direct lubricating oil from the heat exchanger 210 to the compressor 64.

[0034] Within the heat exchanger 210, the lubricating oil can reject heat to the ambient air surrounding the heat exchanger 210. The lubricating oil flows from the heat exchanger 210 back to the compressor 64 via the lubricating oil conduit 220. In this manner, the lubricating oil conduit 220 can circulate the lubricating oil between the compressor 64 and the heat exchanger 210, and the heat exchanger 210 can reduce the temperature of the lubricating oil from the compressor 64 before returning the lubricating oil to the compressor 64. Thus, the oil cooling circuit 200 can remove the lubricating oil from the compressor 64 via the lubricating oil conduit 220 and return the lubricating oil to the compressor 64 via the lubricating oil conduit 220 after cooling the lubricating oil in the heat exchanger 210.

[0035] In some embodiments, the heat exchanger 210 is positioned at or adjacent to the fan 72. For example, the heat exchanger 210 can be positioned and oriented so that the fan 72 pulls or pushes air through the heat exchanger 210 to provide forced convection for more rapid and efficient heat exchange between the lubricating oil within the heat exchanger 210 and the ambient air surrounding the refrigeration system 60. In certain exemplary embodiments, the heat exchanger 210 can be positioned between the fan 72 and the condenser 66. Thus, the heat exchanger 210 can be positioned downstream of the fan 72 and upstream of the condenser 66 relative to the air flow from the fan 72. In this manner, the air from the fan 72 can exchange heat with the lubricating oil in the heat exchanger 210 before exchanging heat with the refrigerant in the condenser 66.

[0036] In additional or alternative embodiments, heat exchanger 210 is positioned at or on condenser 66. For example, heat exchanger 210 can be mounted to condenser 66 such that heat exchanger 210 and condenser 66 are in thermal communication with each other. Thus, condenser 66 and heat exchanger 210 can exchange heat conductively. In this manner, heat exchanger 210 and condenser 66 can exchange heat between the lubricating oil within heat exchanger 210 and the refrigerant within condenser 66.

[0037] In certain exemplary embodiments, the heat exchanger 210 can be a tube-to-tube heat exchanger 210 that is integrated within or on (e.g., a portion of) the condenser 66. For example, the heat exchanger 210 can be welded or soldered to the condenser 66. In alternative embodiments, the heat exchanger 210 is disposed on a portion of the condenser 66 between the inlet and the outlet of the condenser 66. For example, the refrigerant can enter the condenser 66 at the inlet of the condenser 66 at a first temperature (e.g., one hundred and fifty degrees Fahrenheit (150°F)), and the heat exchanger 210 can be positioned on the condenser 66 downstream of the inlet of the condenser 66 such that the refrigerant immediately upstream of the portion of the condenser 66 where the heat exchanger 210 is mounted can have a second temperature (e.g., ninety degrees Fahrenheit (90°F)).

[0038] Heat exchanger 210 may also be positioned on condenser 66 upstream of the outlet of condenser 66 such that the refrigerant immediately downstream of the portion of condenser 66 where heat exchanger 210 is mounted may have a third temperature (e.g., one hundred and five degrees Fahrenheit (105°F)) and the refrigerant may exit condenser 66 at the outlet of condenser 66 at a fourth temperature (e.g., ninety degrees Fahrenheit (90°F)). Thus, during operation of compressor 64, the temperature of the refrigerant within condenser 66 at the portion of condenser 66 where heat exchanger 210 is mounted may increase in order to cool the lubricating oil within heat exchanger 210. However, the portion of condenser 66 downstream of heat exchanger 210 may assist in rejecting heat to the ambient air surrounding condenser 66.

[0039] 2 shows an oil cooling circuit 200, alternative embodiments may be provided having different cooling configurations for the oil within the compressor 64. Therefore, unless otherwise indicated, FIG. 2 is provided for illustrative purposes only and does not limit the present disclosure.

[0040] Turning now to Figures 3 and 4 , various cross-sectional views of a linear compressor 300 according to an exemplary embodiment of the present disclosure are provided. As discussed in more detail below, the linear compressor 300 is operable to increase the pressure of a fluid within a compartment 312 of the linear compressor 300. The linear compressor 300 can be used to compress any suitable fluid, such as a refrigerant. Specifically, the linear compressor 300 can be used in a refrigeration appliance, such as the refrigeration appliance 10 (Figure 1), where the linear compressor 300 can be used as the compressor 64 (Figure 2). As shown in Figure 3 , the linear compressor 300 defines an axial direction A and a radial direction R. The linear compressor 300 can be enclosed within a sealed or airtight housing 302. In other words, the linear compressor 300 can be enclosed within an interior volume 303 defined by the housing 302. For example, the linear compressor can be supported within the interior volume 303 by one or more mounting springs 305, which generally inhibit vibration or movement of the linear compressor 300 relative to the housing 302. When assembled, the sealed housing 302 hinders or prevents the refrigerant or lubricating oil from leaking or escaping the refrigeration system 60 ( FIG. 2 ).

[0041] The linear compressor 300 includes a housing 308 extending between a first end portion 304 and a second end portion 306 (e.g., along an axial direction A). The housing 308 includes various relatively stationary or immobile structural components of the linear compressor 300. Specifically, the housing 308 includes a cylinder assembly 310 that defines a compartment 312. The cylinder assembly 310 can be positioned at or adjacent to the second end portion 306 of the housing 308. The compartment 312 can extend longitudinally along the axial direction A.

[0042] In some embodiments, the motor-mounted intermediate section 314 of the housing 308 (e.g., at the second end portion 306) supports the stator of the motor. As shown, the stator can include an outer back iron 364 and a drive coil 366 sandwiched between the first end portion 304 and the second end portion 306. The linear compressor 300 can also include one or more valves (e.g., a discharge valve assembly 320 at the end of the compartment 312) that allow refrigerant to enter and exit the compartment 312 during operation of the linear compressor 300.

[0043] In some embodiments, the exhaust valve assembly 320 is mounted to the housing 308 (eg, at the second end portion 306 ). The exhaust valve assembly 320 can include a muffler housing 322 , a valve head 324 , and a valve spring 338 .

[0044] The muffler housing 322 may include an end wall 326 and a cylindrical sidewall 328. The cylindrical sidewall 328 is mounted to the end wall 326, and the cylindrical sidewall 326 extends from the end wall 326 (e.g., in the axial direction A) to the cylindrical assembly 310 of the shell 308. A refrigerant outlet conduit 330 may extend from or through the muffler housing 322 and through the outer shell 302 (e.g., to or in fluid communication with the condenser 66 of FIG. 2 ) to selectively allow refrigerant to discharge from the discharge valve assembly 320 during operation of the linear compressor 300.

[0045] The muffler housing 322 can be mounted or secured to the shell 308, and other components of the discharge valve assembly 320 can be disposed within the muffler housing 322. For example, a plate 332 of the muffler housing 322 at the distal end of the cylindrical sidewall 328 can be positioned at or on the barrel assembly 310, and a seal (e.g., an O-ring or gasket) can extend between the barrel assembly 320 and the plate 332 of the muffler housing 322 (e.g., in the axial direction A) to limit fluid leakage at the axial gap between the shell 308 and the muffler housing 322. Other seals can extend through the plate 332 into the shell 308 to mount the muffler housing 322 to the shell 308.

[0046] In some embodiments, the valve head 324 is positioned at or adjacent to the compartment 312 of the cylinder assembly 310. The valve head 324 can optionally form a passage extending through the cylinder assembly 310 (e.g., in the axial direction A). Such a passage can be proximate to the compartment 312. When assembled, a valve spring 338 can be coupled to the muffler housing 322 and the valve head 324. The valve spring 338 can be configured to urge the valve head 324 toward or against the cylinder assembly 310 (e.g., in the axial direction A).

[0047] A piston assembly 316 with a piston head 318 is slidably received within the compartment 312 of the cylinder assembly 310. Specifically, the piston assembly 316 can slide in the axial direction A within the compartment 312. While the piston head 318 slides within the compartment 312, the piston head 318 compresses the refrigerant within the compartment 312. For example, from the top dead center position, the piston head 318 can slide in the axial direction A within the compartment 312 toward the bottom dead center position (e.g., the expansion stroke of the piston head 318). When the piston head 318 reaches the bottom dead center position, the piston head 318 changes direction and slides backward within the compartment 312 toward the top dead center position (e.g., the compression stroke of the piston head 318). When the piston head 318 reaches the top dead center position, or before the piston head 318 reaches the top dead center position, the expansion valve assembly 320 can open. For example, the valve head 324 may be pushed away from the cylinder assembly 310 , allowing refrigerant to drain from the compartment 312 and through the discharge valve assembly 320 to the refrigerant outlet conduit 330 .

[0048] It should be understood that the linear compressor 300 may include additional piston heads or additional compartments at the opposite end (eg, near the first end portion 304) of the linear compressor 300. Thus, in alternative exemplary embodiments, the linear compressor 300 may have multiple piston heads.

[0049] In certain embodiments, the linear compressor 300 includes an inner back-iron assembly 352. The inner back-iron assembly 352 is positioned within the stator of the electric motor. Specifically, an outer back-iron 364 or drive coil 366 may extend around the inner back-iron assembly 352 (e.g., in a circumferential direction). The inner back-iron assembly 352 also has an outer surface. At least one drive magnet 362 is mounted to the inner back-iron assembly 352 (e.g., at an outer surface of the inner back-iron assembly 352). The drive magnet 362 may face or be exposed to the drive coil 366. Specifically, the drive magnet 362 may be spaced apart from the drive coil 366 (e.g., by an air gap in the radial direction R). Thus, an air gap may be defined between opposing surfaces of the drive magnet 362 and the drive coil 366. The drive magnet 362 may also be mounted or secured to the inner back-iron assembly 352 such that the outer surface of the drive magnet 362 is substantially flush with the outer surface of the inner back-iron assembly 352. Thus, the drive magnet 362 may be inserted into the inner back-iron assembly 352. In such a manner, during operation of the linear compressor 300 , the magnetic field of the drive coil 366 may have to pass through only a single air gap between the outer back-iron 364 and the inner back-iron assembly 352 .

[0050] As can be seen in FIG3 , the drive coil 366 extends around the inner back iron assembly 352 (e.g., in a circumferential direction). Generally, during operation of the drive coil 366, the drive coil 366 can be operated to move the inner back iron assembly 352 in an axial direction A. For example, a current source (e.g., included in or in conjunction with the controller 367) can induce a current in the drive coil 366 to generate a magnetic field that engages the drive magnet 362 and forces the piston assembly 316 to move in the axial direction A to compress the refrigerant within the compartment 312, as described above. Specifically, the magnetic field of the drive coil 366 can engage the drive magnet 362 to move the inner back iron assembly 352 and the piston head 318 in the axial direction A during operation of the drive coil 366. Thus, during operation of the drive coil 366, the drive coil 366 can cause the piston assembly 316 to slide between a top dead center position and a bottom dead center position.

[0051] In an optional embodiment, linear compressor 300 includes various components for enabling or regulating the operation of linear compressor 300. Specifically, linear compressor 300 includes a controller 367 configured to regulate the operation of linear compressor 300. For example, controller 367 can be operable to communicate with the electric motor (e.g., the drive coil 366 of the electric motor). Thus, controller 367 can selectively activate drive coil 366, for example by supplying current to drive coil 366, to compress refrigerant using piston assembly 316, as described above. In some embodiments, controller 367 directs or regulates the current according to a predetermined control loop. For example, as will be appreciated, such a control loop can regulate the supply voltage (e.g., peak voltage or root mean square (RMS) voltage) of the supply current to a desired reference voltage. To this end, controller 367 can include suitable components for measuring or estimating the supply current, such as an ammeter. Additionally or alternatively, controller 367 can be configured (e.g., according to one or more programmed methods, such as method 700) to detect or mitigate internal collisions.

[0052] Controller 367 includes memory and one or more processing devices, such as a microprocessor, CPU, or the like, such as a general-purpose microprocessor or a dedicated microprocessor capable of executing programmed instructions or microcontrol code associated with the operation of linear compressor 300. Memory may represent random access memory (such as DRAM) or read-only memory (such as ROM or FLASH). The processor executes the programmed instructions stored in the memory. The memory may be a separate component from the processor or may be onboard the processor. Alternatively, controller 367 may be configured to perform control functions without the use of a microprocessor (e.g., using a combination of discrete analog logic circuits or digital logic circuits, such as switches, amplifiers, integrators, comparators, flip-flops, and AND gates), rather than relying on software.

[0053] The linear compressor 300 also includes one or more spring assemblies (e.g., 340, 342) mounted to the housing 308. In particular embodiments, a pair of spring assemblies (e.g., a first spring assembly 340 and a second spring assembly 342) define the drive coil 366 along the axial direction A. In other words, the first spring assembly 340 is positioned adjacent to the first end portion 304 and the second spring assembly 342 is positioned adjacent to the second end portion 306.

[0054] In some embodiments, spring assembly 340 and spring assembly 342 each include one or more planar springs mounted or secured to one another. As will be described in greater detail below, the planar springs can be mounted or secured to one another such that each planar spring of the respective assembly 340 or assembly 342 is spaced apart from one another (e.g., along axial direction A).

[0055] Typically, the pair of spring assemblies 340, 342 assist in coupling the inner back iron assembly 352 to the housing 308. In some such embodiments, a first set of external fasteners 344 (e.g., bolts, nuts, clamps, tabs, welds, solder, etc.) secure the first and second spring assemblies 340, 342 to the housing 308 (e.g., a bracket of the stator), while a first set of internal fasteners 346 radially inward from the first set of external fasteners 344 (e.g., in a perpendicular radial direction R and closer to the axial direction A) secure the first spring assembly 340 to the inner back iron assembly 352 at the first end portion 304. In additional or alternative embodiments, a second set of internal fasteners 350 radially inward from the first set of external fasteners 344 (e.g., in a perpendicular radial direction R and closer to the axial direction A) secures the second spring assembly 342 to the inner back iron assembly 352 at the second end portion 306.

[0056] During operation of the drive coil 366, the spring assemblies 340, 342 support the inner back iron assembly 352. Specifically, the inner back iron assembly 352 is suspended within the stator or motor of the linear compressor 300 by the spring assemblies 340, 342 such that movement of the inner back iron assembly 352 in the radial direction R is hindered or restricted, while movement in the axial direction A is relatively unimpeded. Thus, the spring assemblies 340, 342 can be substantially less mobile in the radial direction R than in the axial direction A. In this manner, the spring assemblies 340, 342 can help maintain a uniform air gap (e.g., in the radial direction R) between the drive magnet 362 and the drive coil 366 during operation of the motor and movement of the inner back iron assembly 352 in the axial direction A. The spring assemblies 340, 342 can also help prevent side pull forces of the motor from being transmitted to the piston assembly 316 and reacted as friction losses in the cylinder assembly 310.

[0057] In an alternative embodiment, the inner back iron assembly 352 includes an outer cylinder 354 and a sleeve 360. The sleeve 360 ​​is positioned on or at the inner surface of the outer cylinder 354. A first interference fit between the outer cylinder 354 and the sleeve 360 ​​can couple or secure the outer cylinder 354 and the sleeve 360 ​​together. In an alternative exemplary embodiment, the sleeve 360 ​​can be welded, bonded, fastened, or connected to the outer cylinder 354 via any other suitable mechanism or method.

[0058] When assembled, sleeve 360 ​​can extend about an axial direction A (e.g., in a circumferential direction). In an exemplary embodiment, a first interference fit between outer cylinder 354 and sleeve 360 ​​can couple or secure outer cylinder 354 and sleeve 360 ​​together. In alternative exemplary embodiments, sleeve 360 ​​can be welded, bonded, fastened, or otherwise attached to outer cylinder 354 via any other suitable mechanism or method. As shown, sleeve 360 ​​extends within outer cylinder 354 (e.g., in an axial direction A) between first end portion 304 and second end portion 306 of inner back iron assembly 352. First spring assembly 340 and second spring assembly 342 are mounted to sleeve 360 ​​(e.g., using a set of internal fasteners 346 and internal fasteners 350).

[0059] The outer cylinder 354 can be made of or use any suitable material. For example, the outer cylinder 354 can be made of or use a plurality of thin sheets (e.g., ferromagnets). These thin sheets are distributed in the circumferential direction to form the outer cylinder 354 and are mounted or fixed to each other (e.g., using a ring crimped onto the end of the sheet). The outer cylinder 354 defines a recess extending inwardly (e.g., in the radial direction R) from the outer surface of the outer cylinder 354. The drive magnet 362 can be positioned in the recess on the outer cylinder 354 (e.g., so that the drive magnet 362 is inserted into the outer cylinder 354).

[0060] In some embodiments, a piston flexible mount 368 is mounted to and extends through the inner back iron assembly 352. Specifically, the piston flexible mount 368 is mounted to the inner back iron assembly 352 via the sleeve 360 ​​and the spring assemblies 340 and 342. Thus, the piston flexible mount 368 can be coupled (e.g., threaded) to the sleeve 360 ​​to mount or secure the piston flexible mount 368 to the inner back iron assembly 352. A coupling 370 extends between the piston flexible mount 368 and the piston assembly 316 (e.g., in the axial direction A). Thus, the coupling 370 connects the inner back iron assembly 352 and the piston assembly 316 so that movement of the inner back iron assembly 352 (e.g., in the axial direction A) is transmitted to the piston assembly 316. The coupling 370 can extend through the drive coil 366 (e.g., in the axial direction A).

[0061] The piston flexible mount 368 can define at least one passage 369. The passage 369 of the piston flexible mount 368 extends (e.g., in the axial direction A) through the piston flexible mount 368. Thus, during operation of the linear compressor 300, a flow of fluid (such as air or refrigerant) can move through the piston flexible mount 368 via the passage 369 of the piston flexible mount 368. As shown, one or more refrigerant inlet conduits 331 can extend through the housing 302 to return refrigerant from the evaporator 70 (or another portion of the sealing system 60) ( FIG. 2 ) to the compressor 300.

[0062] The piston head 318 also defines at least one opening (e.g., selectively covered by a head valve). The opening of the piston head 318 extends (e.g., in the axial direction A) through the piston head 318. Thus, during operation of the linear compressor 300, refrigerant flow can move through the piston head 318 via the opening of the piston head 318 and into the compartment 312. In this manner, during operation of the linear compressor 300, the flow of fluid (compressed by the piston head 318 within the compartment 312) can flow through the piston flexible mount 368 and the inner back iron assembly 352 to reach the piston assembly 316.

[0063] As shown, the linear compressor 300 may include features for directing oil through the linear compressor 300 and the oil cooling circuit 200 ( FIG. 2 ). One or more oil inlet conduits 380 or oil outlet conduits 382 may extend through the housing 302 to direct oil to or from the oil cooling circuit 200. Alternatively, however, it should be understood that other configurations for directing oil within the housing 302 may be provided. For example, the oil may be recirculated only within the housing 302 (i.e., without circulating the oil to / from the cooling circuit 200). Additionally or alternatively, one or more conduits within the housing 302 may be connected to an internal hot wall heat exchanger for cooling the oil as it sinks back to the oil sump 376.

[0064] Optionally, the oil inlet conduit 380 may be coupled to the return conduit 224 of the oil cooling circuit 200 ( FIG. 2 ). Thus, lubricating oil may flow from the heat exchanger 210 to the linear compressor 300 via the oil inlet conduit 380. Alternatively, the oil inlet conduit 380 may be positioned at or adjacent to the oil sump 376. Thus, lubricating oil from the linear compressor 300 that reaches the oil inlet conduit 380 may flow into the oil sump 376. As described above, the oil cooling circuit 200 may cool the lubricating oil from the linear compressor 300. After such cooling, the lubricating oil returns to the linear compressor 300 via the oil inlet conduit 380. Thus, the lubricating oil in the oil inlet conduit 380 may be relatively cool and assist in cooling the lubricating oil in the oil sump 376.

[0065] In some embodiments, the linear compressor 300 includes a pump 372. The pump 372 can be positioned at or adjacent to an oil sump 376 of the housing 302 (e.g., within the pump housing 374). The oil sump 376 corresponds to a portion of the housing 302 located at or adjacent to the bottom of the housing 302. Consequently, a certain amount of lubricating oil 377 within the housing 302 can collect within the oil sump 376 (e.g., because the density of the lubricating oil is greater than the density of the refrigerant within the housing 302). During use, the pump 372 can draw lubricating oil from the volume 377 within the oil sump 376 into the pump 372 via a supply line 378 extending from the pump 372 to the oil sump 376. For example, when the pump 372 oscillates within the pump housing 374 (e.g., driven by the oscillation of the shell 308), a pair of check valves within the pump housing 374 at opposite ends of the pump 372 can selectively allow / release oil to / from the pump housing 374. Additionally or alternatively, when the pump 372 is actively oscillating, the volume of lubricant 377 may be maintained at a predetermined level (eg, even at the vertical midpoint of the pump 372).

[0066] The internal conduit 384 can extend from the pump 372 (e.g., the pump housing 374) to a reservoir 386 defined within the shell 308. In some embodiments, the reservoir 386 is positioned radially outward from the compartment 312 of the cylinder assembly 310. For example, the reservoir 386 can be defined to extend in a circumferential direction (e.g., about the axial direction A) as an annular compartment surrounding the compartment 312 of the cylinder assembly 310.

[0067] Typically, lubricating oil can be selectively directed from the oil reservoir 386 to the cylinder assembly 310. Specifically, one or more channels (e.g., radial channels) can extend from the oil reservoir 386 to the compartment 312. Such radial channels can terminate at a portion of the sliding path of the piston head 318 (e.g., between the top dead center and the bottom dead center relative to the axial direction A). When the piston head 318 slides within the compartment 312, the sidewalls of the piston head 318 can receive lubricating oil. In an alternative embodiment, the radial channels terminate at a groove 388 defined by the cylinder assembly 310 within the compartment 312. Thus, the groove 388 can be open to the compartment 312. Lubricating oil from the oil reservoir 386 can flow into the compartment 312 of the cylinder assembly 310 (e.g., via the radial channels leading to the groove 388) to lubricate the movement of the piston assembly 316 within the compartment 312 of the cylinder assembly 310.

[0068] The housing 308, along with the compartment 312 and the oil reservoir 386, may define an oil drain port 390. In some embodiments, the oil drain port 390 extends from the oil reservoir 386. For example, the oil drain port 390 may extend outward from the oil reservoir 386 through the housing 308. Thus, the oil drain port 390 may be in fluid communication with the oil reservoir 386. During use, at least a portion of the lubricating oil drawn into the oil reservoir 386 may flow toward the oil drain port 390 (e.g., as driven by the pump 372). The lubricating oil may exit the housing 308 (and generally, the linear compressor 300) from the oil drain port 390. In particular embodiments, the oil drain port 390 is fluidically coupled to an oil outlet conduit 382. Thus, the pump 372 may generally draw lubricating oil from the interior volume 303 through the housing 308 and to the oil outlet conduit 382. The oil outlet conduit 382 may be coupled to the supply conduit 222 ( FIG. 2 ) of the oil cooling circuit 200. Thus, the pump 372 can push lubricating oil from the sump 376 into the supply conduit 222. In this manner, the pump 372 can supply lubricating oil to the oil cooling circuit 200 to cool the lubricating oil from the linear compressor 300, as described above.

[0069] Separate from or in addition to the oil drain port 390, the housing 308 may define a gas drain port 392. Specifically, the gas drain port 392 extends from the oil reservoir 386 through the interior volume 303. As shown, the gas drain port 392 is defined to be fluidly parallel to the oil drain port 390. Thus, fluid is directed through the gas drain port 392 and the oil drain port 390 separately. Generally, the dimensions of the gas drain port 392 may provide greater fluid constraints than the oil drain port 390. For example, the minimum diameter of the gas drain port 392 may still be smaller than the minimum diameter of the oil drain port 390. Alternatively, the minimum diameter of the gas drain port 392 may be less than 2 mm, while the minimum diameter of the oil drain port is greater than 4 mm. In addition to its smaller diameter, the gas drain port 392 may also be shorter in length than the oil drain port 390. During typical pumping operation, a larger volume of lubricating oil can be driven through the oil drain port 390 compared to the gas drain port 392. However, gas (eg, generated within sump 386 during deflation) may be permitted to pass through gas discharge port 392 to interior volume 303 while allowing lubricating oil to continue flowing from sump 386 to drain port 390 or compartment 312 .

[0070] A gas discharge port 392 can be defined at an upper portion of the housing 308 (e.g., at an upper end of the oil reservoir 386). Additionally or alternatively, the gas discharge port 392 can extend above the discharge valve assembly 320 (e.g., parallel to the axial direction A). The gas discharge port 392 can also be located below the oil drain port 390 (e.g., lower than the oil drain port along the vertical direction V). In some embodiments, the gas discharge port 392 is located at the second end portion 306 of the housing 308. Fluid from the gas discharge port 392 can be directed forward into the interior volume 303.

[0071] In some embodiments, an oil shield 394 is disposed in front of the gas discharge port 392. As shown, the oil shield 394 can be disposed on the shell 308 (e.g., at the second end portion 306). A drip channel can be defined between the oil shield 394 and, for example, the muffler housing 322. For example, the oil shield 394 can extend outward from the shell 308 to a curved or inwardly extending wall portion 396. Additionally or alternatively, the oil shield 394 can extend around a portion of the muffler housing 322. For example, the oil shield 394 can extend 180° along the top side of the muffler housing 322. During use, lubricating oil discharged through the gas discharge port 392 can be directed downwardly to the oil sump 376. During use, the oil shield 394 can prevent lubricating oil from impacting the shell 302 (e.g., at high speeds that could otherwise cause the lubricating oil within the interior volume 303 to atomize).

[0072] Turning now to Figures 5-7 , the planar spring assembly 500 will be described in greater detail. As will be appreciated, the planar spring assembly 500 can be provided with a suitable linear compressor (e.g., compressor 300 - Figure 3 ), such as with or as spring assembly 340 or spring assembly 342 ( Figure 3 ). Generally, the planar spring assembly 500 includes a plurality (e.g., at least two) of planar springs 510 spaced apart from one another (e.g., along an axial direction A). Thus, the planar spring assembly 500 includes at least a first planar spring 510 and a second planar spring 510. Additional planar springs 510 may be provided, such as four ( Figure 5 ) or three ( Figures 6 and 7 ). However, as will be appreciated in light of this disclosure and unless otherwise indicated, the planar spring assembly 500 is not limited to any particular number of planar springs 510, nor to any particular number thereof.

[0073] When assembled, each planar spring 510 is disposed along (or otherwise defines) a radial plane perpendicular to the axial direction A. Thus, each planar spring 510 extends along a radial direction R perpendicular to the axial direction A. Furthermore, each planar spring 510 of the planar spring assembly 500 can be parallel to some or all of the other planar springs 510. In some embodiments, each planar spring 510 defines a flat front face 512 and a flat back face 514 parallel to the flat front face 512. For example, the flat front face 512 and the flat back face 514 can each extend directly along and parallel to the radial direction R (e.g., without undulations or deviations from the radial plane).

[0074] Each planar spring 510 can be formed from a metal material (e.g., stainless steel). In some such embodiments, the planar spring 510 is formed from a single piece of sheet metal. Thus, the front face 512 and the back face 514 can generally maintain the same flat sheet metal shape, and, for example, the thickness between the front face 512 and the back face 514 (i.e., along the axial direction A) can remain approximately the same as the thickness of the original sheet metal. Alternatively, the planar spring 510 can be cut or stamped from a raw sheet metal material.

[0075] In a particular embodiment, the planar spring 510 defines a central void 516 extending in the axial direction A. The inner ring 518 may generally extend circumferentially around the central void 516 or around the axial direction A. The inner ring 518 may be continuous or uninterrupted along the circumferential direction C. Furthermore, the inner ring 518 may surround the central void 516 along the circumferential direction C. Optionally, one or more annular holes 520 may be defined (e.g., parallel to the axial direction A) through the inner ring 518, such as to receive an internal fastener (e.g., fastener 350 - FIG. 3 ). As shown, a plurality of annular holes 520 may be defined through each inner ring 518 and circumferentially spaced apart from each other (e.g., defined as discrete circumferential locations).

[0076] In some embodiments, one or more radial arms 522 may extend from the inner ring 518 to a corresponding distal tip 524 (e.g., continuously with the inner ring 518 or as a separately attached member connected to the inner ring 518). A mounting tab 526 may be provided at the distal tip 524. Furthermore, a mounting aperture 528 may be defined (e.g., parallel to the axial direction A) through the mounting tab 526, such as to receive an external fastener 344 ( FIG. 3 ). Optionally, the radial arms 522 may extend radially along an arcuate path that extends along the circumferential direction C. Thus, between the inner ring 518 and the distal tip 524, each radial arm 522 may extend in both the radial direction R and the circumferential direction C (e.g., counterclockwise). In some such embodiments, each radial arm 522 defines a plurality of turns and, thus, circumnavigates the inner ring 518 multiple times. In the illustrated embodiment, at least two turns are formed (e.g., such that each radial arm 522 extends 720° or more around the axial direction A). In additional or alternative embodiments, the distal tips 524 of the radial arms 522 are circumferentially spaced apart. Alternatively, an equal circumferential distance can be defined between each adjacent (eg, circumferentially adjacent) mounting tabs 526.

[0077] As described above, the planar springs 510 are spaced apart from one another (e.g., along the axial direction A). One or more spacer plugs 530A, 530B may be positioned between adjacent (e.g., axially adjacent) planar springs 510 along the axial direction A. Consequently, adjacent planar springs 510 can be maintained at a common axial distance without directly contacting one another. In some such embodiments, such as those having three or more planar springs 510, the spacer plugs 530A, 530B may all define a common axial thickness. Furthermore, a common axial spacing may be provided between each planar spring 510. In other words, each planar spring 510 may be spaced apart from one another by the same distance.

[0078] Separate from or in addition to the spacer plugs 530A, 530B between adjacent (e.g., axially adjacent) planar springs 510, one or more spacer plugs 530A, 530B may be disposed (e.g., directly or indirectly) on both the front face 512 and the back face 514 of the planar spring 510 (e.g., each planar spring 510). Thus, the spacer plugs 530A, 530B may be disposed on the front face 512 of the frontmost planar spring 510 or on the back face 514 of the rearmost planar spring 510, even if no other planar spring 510 is adjacent (e.g., axially adjacent) to the front face 512 or back face 514, respectively. Consequently, the spacer plugs 530A, 530B may be retained between the fastener head and the frontmost planar spring 510 or between the fastener head and the rearmost spring. Additionally, the spacer plugs 530A, 530B prevent the fastener heads from directly contacting the planar spring 510 .

[0079] In certain embodiments, one or more (e.g., some or all) of the spacers 530A and 530B are formed from a metallic material, such as the same metallic material as the planar spring 510. For example, if the planar spring 510 is formed from sheet metal, the spacers 530A and 530B can be formed from the same sheet metal (e.g., from a cut or stamped sheet metal used to form the planar spring 510). Alternatively, a suitable rigid polymer material or other material different from the metallic material of the planar spring 510 can be used.

[0080] Generally, the assembled spring assembly 500 may provide the spacer plugs 530A, 530B on or axially aligned with one or more portions of adjacent (eg, axially adjacent) or corresponding planar springs 510 .

[0081] In some embodiments, one or more inner plugs 530A are located on or axially aligned with the inner ring 518. Thus, the inner plugs 530A can axially separate adjacent (e.g., axially adjacent) planar springs 510 at their corresponding inner rings 518. Such inner plugs 530A can be positioned around the central gap 516, thereby leaving the central gap 516 unobstructed. In some embodiments, multiple discrete inner plugs 530A can extend around the axial direction A. Each inner plug 530A can extend along or occupy a sub-portion (e.g., less than 360°) of the circumferential direction C. Consequently, multiple inner plugs 530A can be used between two adjacent (e.g., axially adjacent) inner rings 518.

[0082] In additional or alternative embodiments, one or more outer plugs 530B are on or axially aligned with the distal tips 524 (e.g., at the mounting tabs 526). Thus, the outer plugs 530B can axially separate adjacent (e.g., axially adjacent) planar springs 510 at their corresponding distal tips 524 or mounting tabs 526. Such outer plugs 530B can be radially spaced from the inner ring 518 (or inner plugs 530A).

[0083] Separate from or in addition to the isolation plugs 530A, 530B, one or more polymer shim layers 540A, 540B may be disposed between adjacent (e.g., axially adjacent) planar springs 510 (or portions thereof). Such polymer shim layers 540A, 540B may directly contact at least one planar spring 510 (e.g., at the corresponding front face 512 or back face 514) and, in particular, prevent another spring, plug, metal component, or sub-portion of the spring 510 from directly contacting at least a portion of the corresponding planar spring 510. Furthermore, such polymer shim layers 540A, 540B may advantageously prevent fretting fatigue from occurring in the planar springs 510.

[0084] Generally, the assembled spring assembly 500 may provide the polymer shim layers 540A, 540B on or axially aligned with one or more portions of adjacent (eg, axially adjacent) or corresponding planar springs 510 .

[0085] In some embodiments, one or more inner shim layers 540A are positioned on or axially aligned with the inner ring 518. Thus, the inner shim layers 540A can axially separate adjacent (e.g., axially adjacent) planar springs 510 at their respective inner rings 518. Such inner shim layers 540A can be positioned to surround the central void 516, thereby leaving the central void 516 unobstructed. In some embodiments, multiple discrete inner shim layers 540A can extend around the axial direction A. Each inner shim layer 540A can extend along or occupy a sub-portion (e.g., less than 360°) of the circumferential direction C. Consequently, multiple inner plugs 530A can be used between two adjacent (e.g., axially adjacent) inner rings 518.

[0086] In additional or alternative embodiments, one or more outer shim layers 540B are on or axially aligned with the distal tips 524 (e.g., at the mounting tabs 526). Thus, the outer shim layers 540B can axially separate adjacent (e.g., axially adjacent) planar springs 510 at their respective distal tips 524 or mounting tabs 526. Such outer shim layers 540B can be radially spaced from the inner ring 518 (or inner plug 530A).

[0087] Separate from or in addition to the polymer shim layers 540A, 540B between adjacent (e.g., axially adjacent) planar springs 510, one or more polymer shim layers 540A, 540B may be disposed (e.g., directly or indirectly) on any spacer plugs 530A, 530B between adjacent planar springs 510. Specifically, the polymer shim layers 540A, 540B may be sandwiched between the spacer plugs 530A, 530B and the planar springs 510 (e.g., at the front face 512 or back face 514 thereof). Thus, the polymer shim layers 540A, 540B may be disposed on the front face 512 of the frontmost planar spring 510 or on the back face 514 of the rearmost planar spring, even if no other planar springs 510 are adjacent (e.g., axially adjacent) to the front face 512 or back face 514, respectively. In some embodiments, a discrete polymer shim layer 540A, 540B can be retained between at least one planar spring 510 and the spacer plug 530A, 530B. Furthermore, the polymer shim layer 540A, 540B can prevent the spacer plug 530A, 530B from directly contacting the planar spring 510. Optionally, the spacer plug 530A, 530B defines a radial plug footprint, wherein the polymer shim layer 540A, 540B defines a radial shim plug footprint that is axially aligned with and larger than the radial plug footprint. Thus, even if some slight (e.g., radial) offset or displacement occurs at the spacer plug 530A, 530B, the corresponding polymer shim layer 540A, 540B can still prevent contact between the spacer plug 530A, 530B and the opposing planar spring assembly 500. If the spacer plugs 530A, 530B are arranged between two adjacent (for example, axially adjacent) planar springs 510, two separate polymer gasket layers 540A, 540B can be arranged between the adjacent planar springs 510, so as to achieve a sequential pattern of forming a first planar spring 510, a first polymer gasket layer 540, 540B, a spacer plug 530A, 530B, a second polymer gasket layer 540, 540B and a second planar spring 510 (for example, as shown in the figure).

[0088] Typically, each polymer gasket layer 540A, 540B is formed by a suitable wear-resistant polymer material. For example, the polymer material may include or be provided as biaxially oriented polyethylene terephthalate (BoPET), polyphenylene sulfide (PPS) or polyetheretherketone (PEEK). Alternatively, a plurality of (e.g., some or all) polymer gasket layers 540A, 540B may be formed by the same material. For example, the outer gasket layer 540B may be formed by the same (e.g., first) polymer material. Additionally or alternatively, two or more polymer gasket layers 540A, 540B may be formed by different materials. For example, the outer gasket layer 540B may be formed by a (e.g., first) polymer material, while the inner gasket layer 540A is formed by another (e.g., second) material that is different from the first polymer material.

[0089] In some embodiments, one or more polymer shim layers 540A, 540B comprise or are provided as a polymer sheet (e.g., as shown). In additional or alternative embodiments, one or more polymer shim layers 540A, 540B comprise or are formed as a polymer coating, which is formed (e.g., directly) onto the surface of the corresponding planar spring 510, such as by liquid coating, overmolding, or vapor deposition, as will be understood in light of the present disclosure. Regardless of whether the polymer shim layers 540A, 540B are a sheet or a coating (or another suitable structure), such polymer shim layers 540, 540B can be relatively thin (e.g., compared to the planar spring 510). For example, the polymer shim layers 540A, 540B can define an axial thickness that is less than or equal to 10% of the axial thickness of the planar spring 510. In some embodiments, the axial thickness of the polymer shim layers 540A, 540B is between 0.03 mm and 0.3 mm. In additional or alternative embodiments, the polymeric spacer layers 540A, 540B have an axial thickness between 0.05 mm and 0.2 mm. In other embodiments, the polymeric spacer layers 540A, 540B have an axial thickness of approximately 0.13 mm.

[0090] This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. If such other examples include structural elements that do not differ from the literal language of the claims, or if such other examples include equivalent structural elements with insignificant differences from the literal language of the claims, such other examples are intended to be within the scope of the claims.

Claims

1. A linear compressor for an electrical appliance, characterized in that: The linear compressor comprises: a housing including a cylindrical assembly defining compartments in an axial direction; a piston slidably received within the compartment of the barrel assembly; Drive coil; an inner back-iron assembly positioned within the drive coil; and A flat spring assembly is mounted to the inner back iron assembly, and the flat spring assembly includes First flat spring, a second planar spring, the second planar spring being axially spaced from the first planar spring, and A polymer shim layer is disposed between at least a portion of the first planar spring and the second planar spring.

2. The linear compressor according to claim 1, characterized in that The first planar spring and the second planar spring include a metal material.

3. The linear compressor according to claim 2, characterized in that The linear compressor further includes a spacer plug disposed between the first planar spring and the second planar spring, wherein the polymer gasket layer is sandwiched between the spacer plug and the first planar spring.

4. The linear compressor according to claim 3, characterized in that The spacer plug includes the metal material.

5. The linear compressor according to claim 4, characterized in that The spacer plug defines a radial plug footprint, wherein the polymer shim layer defines a radial shim plug footprint axially aligned with and larger than the radial plug footprint.

6. The linear compressor according to claim 1, wherein: The first planar spring includes an inner ring, said inner ring extending circumferentially around said axial direction, radial arms extending from the inner ring to the distal tip, wherein the polymer shim layer is an inner shim layer axially aligned with the inner ring, and Wherein, the planar spring assembly further includes an outer shim layer radially spaced apart from the inner shim layer and axially aligned with the radial arm at the distal tip.

7. The linear compressor according to claim 6, characterized in that The inner shim layer comprises a first polymer material, and wherein the outer shim layer comprises a second polymer material, the second polymer material being different from the first polymer material.

8. The linear compressor according to claim 6, wherein: The inner gasket layer comprises a first polymer material, and wherein the outer gasket layer comprises the first polymer material.

9. The linear compressor according to claim 1, wherein: The polymer shim layer includes a polymer sheet.

10. The linear compressor according to claim 1, wherein The polymer shim layer includes a polymer coating formed on the first planar spring.

11. A sealing system for an electrical appliance, characterized in that: The sealing system comprises: A linear compressor defining an axial direction and comprising a housing including a cylindrical assembly defining a compartment; a piston slidably received within the compartment of the barrel assembly; Drive coil; an inner back-iron assembly positioned within the drive coil; and a first planar spring, the first planar spring being mounted to the inner back iron assembly, a second planar spring mounted to the inner back iron assembly and axially spaced from the first planar spring, and a polymer shim layer disposed between at least a portion of the first planar spring and the second planar spring; a housing defining an interior volume surrounding the linear compressor and lubricating oil therein; a condenser in downstream fluid communication with the linear compressor to receive compressed refrigerant therefrom; and An evaporator is in upstream fluid communication with the linear compressor to direct expanded refrigerant thereto.

12. The sealing system according to claim 11, wherein: The first planar spring and the second planar spring include a metal material.

13. The sealing system according to claim 12, wherein: The sealing system further includes a spacer plug disposed between the first planar spring and the second planar spring, wherein the polymer gasket layer is sandwiched between the spacer plug and the first planar spring.

14. The sealing system according to claim 13, wherein: The spacer plug includes the metal material.

15. The sealing system according to claim 14, wherein: The spacer plug defines a radial plug footprint, wherein the polymer shim layer defines a radial shim plug footprint axially aligned with and larger than the radial plug footprint.

16. The sealing system according to claim 11, wherein: The first planar spring includes an inner ring, said inner ring extending circumferentially around said axial direction, radial arms extending from the inner ring to the distal tip, wherein the polymer shim layer is an inner shim layer axially aligned with the inner ring, and The linear compressor further includes an outer shim layer radially spaced apart from the inner shim layer and axially aligned with the radial arm at the distal tip.

17. The sealing system according to claim 16, wherein: The inner shim layer comprises a first polymer material, and wherein the outer shim layer comprises a second polymer material, the second polymer material being different from the first polymer material.

18. The sealing system according to claim 16, wherein: The inner gasket layer comprises a first polymer material, and wherein the outer gasket layer comprises the first polymer material.

19. The sealing system according to claim 11, wherein: The polymer shim layer includes a polymer sheet.

20. The sealing system of claim 11, wherein: The polymer shim layer includes a polymer coating formed on the first planar spring.

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