An electric compressor with a hermetic terminal

Abstract

An electric hermetic compressor comprising a hermetic terminal with terminal pins for electrical connection with a motor inside a hermetic housing. The hermetic terminal forms a cavity, the compressor further comprising a non-conductive sealing element defining an enclosed space in the cavity.

Description

Technical Field

[0001] This invention relates to a hermetically sealed electric compressor with an electric motor. The compressor includes a hermetically sealed terminal as part of the housing and includes at least two terminal pins for electrically connecting at least one winding of the electric motor to an external power source. The power source is typically a grid connection, but can also be a battery connection or a connection to other energy sources.

[0002] The hermetic terminals of this type of compressor typically include a terminal retainer that forms part of the housing and is usually welded to the wall of the housing. The hermetic terminals may include at least two terminal pins made of conductive material. These terminal pins extend through the terminal retainer. Insulating elements are arranged to insulate the terminal pins from the terminal retainer. Background Technology

[0003] A hermetic electric compressor includes an electric motor housed in a sealed housing. Such compressors are used for purposes such as domestic refrigeration, light commercial refrigeration, and heating. The sealed housing contains the refrigerant circulating between the condenser and evaporator. Heat exchange, through a phase change between the liquid and gas phases, enables efficient heating and cooling. Examples of refrigerants include R134a, R407C, R744 (CO2), and R290.

[0004] A hermetically sealed terminal comprises a terminal pin formed of a conductive material (such as various types of alloys, like steel) and a terminal retainer that holds the terminal pin. The terminal retainer is typically made of an alloy such as steel. An insulating element (i.e., a material such as ceramic, glass, or epoxy resin) is arranged between the terminal pin and the terminal retainer, and the terminal retainer is typically welded to an opening in the compressor's sealed housing to maintain the compressor's sealed structure.

[0005] Typically, an electric motor includes a main winding and an auxiliary winding. To supply power to the windings, the sealed terminals include three pins: one for connecting to a common potential, i.e., zero potential or phase, and the other two pins for connecting to each of the main and auxiliary windings. An electric motor can also be a DC motor, or a permanent magnet AC or DC motor, etc. Summary of the Invention

[0006] Embodiments of this disclosure provide an electric compressor that further includes a non-conductive sealing element defining an enclosed space within a cavity.

[0007] During operation, the liquid consisting of lubricant and refrigerant within the housing can contaminate the insulating seals. This liquid often contains metal particles generated by wear and tear on moving metal parts in the compression assembly and electric motor. When the insulating seals are contaminated by this liquid, leakage current may occur between the terminal pins and the terminal retainer (i.e., through the insulating seals).

[0008] Sealing elements can be specifically designed to form the closure of a cavity, thereby protecting the insulating sealing element from contamination by creating a closed space within the cavity.

[0009] Terminal retainers can define an edge extending around the cavity, and sealing elements can be configured to seal against that edge, thereby defining an enclosed space within the cavity.

[0010] The sealing element may include a plug structure configured to electrically engage terminal pins and connect these terminal pins to an electric motor.

[0011] The plug structure can be configured to keep the sealing element against the edge through the engagement between the terminal pin and the plug structure.

[0012] The electric compressor can be positioned to define its operating orientation. This orientation may be particularly necessary for liquid collection at the bottom, etc. The plug design can define the cable direction away from the sealed terminals, with the cable direction downwards relative to gravity when the electric compressor is in the operating orientation.

[0013] The sealing element can form a base and an annular wall that extends upward from the base and is configured to enter the cavity. The annular wall can specifically make sealing contact with the inner surface of the cavity, thereby increasing the sealing condition of the cavity and increasing the fixation of the sealing element on the terminal retainer. The annular wall and the base can be formed as a single unit, for example, made of an elastic or elastically deformable material (e.g., rubber).

[0014] The sealing element may include at least one annular ridge extending upward from the base, such as extending around an annular wall outside the cavity. The annular ridge can form an effective way to prevent liquid on the base from reaching the annular wall. One or more ridges may extend around the annular wall in one or more loops, and these ridges may have a triangular shape in a cross-section transverse to the annulus.

[0015] In one embodiment, at least one of the cavity formed by the terminal retainer, the annular wall, and the annular ridge may be circular. In particular, the cavity and the annular wall may have matching circular shapes and sizes, such that the annular wall can be tightly accommodated in the cavity and held in the cavity by friction between the outer surface of the annular wall and the inner wall of the cavity formed by the terminal retainer.

[0016] At least one annular ridge may extend parallel to the annular wall. This embodiment can be achieved by an annular wall that is coaxially aligned with one or more circular ridges.

[0017] At least one of the annular walls or annular ridges may include at least one notch that defines an opening through the annular wall or annular ridge. The notch may form a groove from the upper edge of the wall or ridge all the way to the base. The notch may allow fluid trapped in the cavity or trapped between the annular wall and one of the ridges to drain through the notch.

[0018] As previously mentioned, the operating orientation of the electric compressor can be defined, for example, based on the location of the liquid collection point, such as the oil pump inlet. When the electric compressor is in the operating orientation, at least one notch can be located relative to gravity in the downward portion of the annular ridge or annular wall.

[0019] In one embodiment, the sealing element includes at least two notches that define an opening through one of the annular walls or annular ridges.

[0020] When the electric compressor is in the operating position, at least two notches can be placed symmetrically with respect to the vertical plane.

[0021] The base can be formed with a flat surface that is transverse to or perpendicular to the terminal pin. This flat surface can be particularly inwardly facing the inner surface of the cavity closed by the sealing element.

[0022] Electric motors can in particular have a main winding and an auxiliary winding used during motor startup. For this purpose, electric compressors can specifically include three terminal pins that extend through a terminal retainer and connect to the electric motor, such that one pin connects to the corresponding winding, while the third pin forms the zero position for both windings.

[0023] In a second aspect, this disclosure provides a method for sealing a cavity for a hermetically sealed terminal of an electric compressor, the method comprising providing a sealing element configured to define a closed space within the cavity, the sealing element having an integral plug structure for retaining the sealing element against an edge of a terminal retainer, thereby defining a closed space within the cavity. Attached Figure Description

[0024] The invention will now be described in more detail with reference to the accompanying drawings, in which:

[0025] Figure 1 A perspective view of the lower half of the compressor housing with hermetically sealed terminals is shown;

[0026] Figure 2 A cross-sectional view of the housing wall and the sealed terminals is shown;

[0027] Figure 3 A conventional sealed terminal is shown;

[0028] Figure 4 A sealed terminal with a floating element is shown;

[0029] Figure 5 The sealing element is shown;

[0030] Figure 6 The sealing element is shown when attached to a sealed terminal; and

[0031] Figure 7 The compressor housing is shown as viewed from above, and the connection between the compression assembly, the hermetically sealed terminals, and the electric motor is schematically illustrated. Detailed Implementation

[0032] The following description relates to embodiments of this disclosure. Figure 1 Half of the compressor housing 1 and a hermetically sealed terminal 2 inserted into the housing wall are shown. The compressor also includes an upper portion (not shown) forming a sealed housing that contains refrigerant, which flows, for example, between the condenser and evaporator of a cooling or heating system via a pipe connection 3. Effective heating and cooling are provided through heat exchange via a phase change between the liquid and gas phases. The compressor houses a compression assembly (e.g., a reciprocating compressor) and an electric motor, such as an AC motor, that drives the compression assembly. The housing and compression assembly are not shown, but can be any kind of known compression assembly and housing.

[0033] Figure 2 A cross-section of the housing wall 4, including the hermetically sealed terminal 2, is shown. The figure shows the terminal retainer 5 welded to the housing wall 4, thus forming part of the housing wall.

[0034] Figure 3 A perspective view of a hermetically sealed terminal is shown, comprising a terminal retainer 5 made of steel and configured to be welded into the compressor housing wall. The hermetically sealed terminal also includes three pins 6, 7, and 8 and three insulating sealing elements 9, 10, and 11 forming an insulating structure. The terminal pins form ends 12 within the compressor housing. These ends are configured for connection to the main and auxiliary windings of an electric motor.

[0035] Figure 4 A view of the sealed terminals is shown, with the cavity defined by the terminal retainer more clearly visible. The inner surface 13 of the terminal retainer 5 is electrically isolated from the terminal pins 6, 7, and 8 by insulating sealing elements 9, 10, and 11. The insulating sealing elements are typically made of glass or a similar non-conductive material. During use, liquids in the housing contaminate the inner surface 13, and metal fragments generated due to tearing and abrasion may create leakage current from the terminal pins to the terminal retainer and through the terminal retainer to the entire compressor housing.

[0036] The cavity formed by the terminal retainer terminates upward from the circumferential edge 14 of the sidewall 15. The sidewall is welded to the compressor housing, thereby forming a single unit with the compressor housing.

[0037] Figure 5 A sealing element 16 is shown, its shape and size adapted to seal the abutment edge 14, thereby defining a closed space within the cavity. This closed space encapsulates the surface of the insulating structure exposed within the cavity.

[0038] In addition to providing a seal to prevent liquid from entering the enclosed space, the sealing element also features an electrical connection to the motor. For this purpose, the sealing element includes plug structures 17, 18 that form a connection plug opening 17 for each terminal pin in the sealed terminals. The plug structures are configured to electrically engage the terminal pins and individually connect these terminal pins to the electric motor via a cable (not shown). After installation, the cable extends through the opening 18, defining the cable direction as indicated by the arrow.

[0039] Each plug opening 17 may include a resilient spring device that forms a firm clamp against the surface of the terminal pin, and the plug structure thereby further serves as a retaining device for holding the sealing element 16 in position against the edge 14 of the terminal retainer 5. The resilient spring device is a commonly known type, such as a resilient spring device from a socket (e.g., from a power outlet).

[0040] The sealing element 16 forms a base 19 and an annular wall 20, the annular wall extending upward from the base and configured to enter the cavity. The annular wall and the terminal retainer have matching dimensions and shapes such that the annular wall fits tightly into the cavity, for example, such that the annular wall 20 contacts the sidewall 15. In this way, the annular wall supports the fixing of the sealing element on the sealing terminal and supports the function of preventing liquid from entering the cavity.

[0041] In the disclosed embodiments, the sealing element further includes a plurality of annular ridges 21 extending upward from the base. The annular ridges are lower than the annular wall 20, but extend parallel to the annular wall and circumferentially surround it. In the disclosed embodiments, both the ridges and the wall are circular. When the sealing element is attached to the terminal retainer, the annular ridges extend outside the cavity.

[0042] Both the annular wall and the annular ridge include notches 22. These notches provide discontinuity in the wall and ridge, thereby defining openings through the wall and / or ridge.

[0043] Electric compressors can be positioned in a specific direction. This direction is typically determined by gravity acting on the liquid inside the casing, ensuring that lubricating oil reaches the oil pump, etc. Figure 6An orientation is shown where, when the electric compressor is in the operating orientation, the cable direction, indicated by the arrow, is downward relative to gravity. When the electric compressor is in the operating orientation, the notch is also located below the annular ridge or annular wall relative to gravity, and any liquid that may have entered the cavity can thus be discharged downward by gravity. When the electric compressor is in the operating orientation, the notch is symmetrically positioned relative to the vertical plane.

[0044] exist Figure 6 In this configuration, a sealing element is attached to a sealing terminal. In the illustrated embodiment, a base is formed with a surface perpendicular to the terminal pin.

[0045] In all the illustrations, the sealed terminal comprises three terminal pins. This corresponds to the zero pin and a phase for each winding of a motor with a main winding and an auxiliary winding. However, other numbers of terminal pins and other ways of connecting the terminal pins to the motor are contemplated in this disclosure, such as two terminal pins used to connect the phase and zero pins to a motor that requires only one phase connector (e.g., a motor with only one winding).

[0046] Figure 7 A top view of the compressor housing is shown, and the compression assembly 23 and the cable 24 connecting the terminal pin to the electric motor 25 are schematically shown.

Claims

1. An electric compressor, comprising: -Compression components - An electric motor, which is arranged to drive a compression assembly; - Compressor housing (1), which is formed as a sealed enclosure for an electric motor and a compression assembly; and -Sealed terminals, including: ○ Terminal retainer (5), which defines a cavity and forms part of the compressor housing (1), ○ At least two conductive terminal pins (6, 7, 8) extending through the terminal retainer (5) and connected to the electric motor, and ○ Insulating structure (9, 10, 11) that insulates the terminal pin from the terminal holder and has a surface exposed in the cavity. The electric compressor also includes a sealing element (16) that defines a closed space within the cavity. The sealing element (16) forms a base (19) and an annular wall (20) extending upward from the base and into the cavity, and wherein the sealing element includes at least one annular ridge (21) extending upward from the base and extending around the annular wall outside the cavity.

2. The electric compressor according to claim 1, characterized in that, The sealing element (16) is non-conductive.

3. The electric compressor according to claim 1 or 2, characterized in that, The terminal retainer defines an edge extending around the cavity, and the sealing element is configured to seal against the edge, thereby defining an enclosed space within the cavity.

4. The electric compressor according to claim 3, characterized in that, The sealing element includes a plug structure (17, 18) configured to electrically engage the terminal pin and connect the terminal pin to the electric motor.

5. The electric compressor according to claim 4, characterized in that, The plug structure (17, 18) is configured to hold the sealing element against the edge by the engagement between the terminal pin and the plug structure.

6. The electric compressor of claim 4, defining an operating orientation, wherein the plug structure (17, 18) defines a cable direction extending away from the sealed terminal, wherein the cable direction is downward relative to gravity when the electric compressor is in the operating orientation.

7. The electric compressor according to claim 1, characterized in that, The at least one annular ridge (21) extends parallel to the annular wall (20).

8. The electric compressor according to claim 1, characterized in that, At least one of the annular wall or annular ridge includes at least one notch (22) that defines an opening through the annular wall or annular ridge.

9. The electric compressor according to claim 8, wherein the operating orientation is defined, and wherein, When the electric compressor is in the operating position, at least one notch (22) is located in the downward portion of the annular ridge or annular wall relative to gravity.

10. The electric compressor according to claim 8 or 9, comprising at least two notches (22) defining an opening through one of the annular wall or annular ridge.

11. The electric compressor according to claim 10, characterized in that, When the electric compressor is in the operating position, the at least two notches (22) are symmetrical with respect to the vertical plane.

12. The electric compressor according to claim 1, characterized in that, The base (19) forms a surface perpendicular to the terminal pins (6, 7, 8).

13. The electric compressor of claim 1, comprising three terminal pins (6, 7, 8) extending through a terminal retainer and connected to an electric motor.

14. The electric compressor according to claim 13, characterized in that, The terminal pins extend through and contact the sealing element, which electrically insulates the terminal pins from each other.

15. The electric compressor according to claim 1, comprising a refrigerant in a compressor housing, said refrigerant being selected from R134a, R407C, R744 (CO2) and R290.

16. The electric compressor according to claim 1, characterized in that, The insulation structure includes insulating sealing elements (9, 10, 11) for each terminal pin, each insulating sealing element insulates the terminal pin from the terminal retainer and has a surface exposed in the cavity.

17. A method for sealing a cavity of a hermetically sealed terminal of an electric compressor, the method comprising providing a sealing element configured to define a closed space in a cavity, the sealing element having an integral plug structure and the plug structure being used to retain the sealing element against an edge of a terminal retainer thereby defining a closed space in the cavity, wherein the sealing element forms a base (19) and an annular wall (20) extending upward from the base and into the cavity, and the sealing element includes at least one annular ridge (21) extending upward from the base.

Images