EP4621230A1

EP4621230A1 - Compressor

Info

Publication number: EP4621230A1
Application number: EP25164031.4A
Authority: EP
Inventors: Jun Yoshida; Sayaka OBATA; Yukiko Matsumoto
Original assignee: Panasonic Intellectual Property Management Co Ltd
Current assignee: Panasonic Intellectual Property Management Co Ltd
Priority date: 2024-03-19
Filing date: 2025-03-17
Publication date: 2025-09-24
Also published as: JP2025144254A

Abstract

A compressor (22) including: a compressor main unit (42) that compresses a flammable refrigerant; a hermetic terminal (44) that is provided to the compressor main unit (42) and to which wiring (49) providing external electrical connection is connected; a seal member (45) that is provided on the outside of an outer surface of the compressor main unit (42); a terminal cover (46) that is attached to the compressor main unit (42) with the seal member (45) interposed between the terminal cover (46) and the compressor main unit (42), and that covers the hermetic terminal (44); and fixing units (47, 48) that fix the terminal cover (46) to the compressor main unit (42), in which the fixing units (47, 48) are provided at substantially symmetrical positions about the hermetic terminal (46).

Description

BACKGROUND

1. Technical Field

The present disclosure relates to a compressor having a sealed structure, and provided with a terminal cover used for the sealed structure.

2. Description of the Related Art

PTL 1 discloses a compressor for a refrigeration cycle apparatus. This compressor is provided in a sealed container, and has a hermetic terminal that is to be electrically connected to a device inside the sealed container, and a cover that covers and protects the hermetic terminal.
This compressor includes: a terminal cover that covers the hermetic terminal, and that has a wiring opening through which a lead wire to be connected to the hermetic terminal passes; a fixing portion that fixes the terminal cover to the sealed container; a seal member that is nipped between the terminal cover and the sealed container and prevents passage of gas; and a bushing that is made of a metal, that is disposed inside the wiring opening of the terminal cover to protect the lead wire, and that is provided with a mesh of 30 mesh or more. Inside and outside of the terminal cover are connected to each other by a gap having a size of 0.9 mm or less.
Further, PTL 2 discloses a compressor facilitating the connection of a wire to a hermetic terminal, and capable of improving the ease of assembly of the hermetic terminal cover.
This compressor includes: a sealed container; a compression mechanism housed inside of the sealed container; an electric motor that drives the compression mechanism; a hermetic terminal provided to the sealed container; wiring connected to the hermetic terminal, on the outer side of the sealed container; a first cover having a shape surrounding the hermetic terminal on an outer surface side of the sealed container and holding the wiring; a second cover attached to the first cover in a manner covering the first cover and forming a sealed cover internal space together with the first cover; and a fixing unit for attaching the first cover and the second cover to the sealed container, in which a contact surface between the first cover and the second cover is inclined with respect to an attachment surface of the hermetic terminal.

Citation List

Patent Literature

PTL 1: Unexamined Japanese Patent Publication No. 2021-032129
PTL 2: Unexamined Japanese Patent Publication No. 2023-176502

SUMMARY

The present disclosure provides a compressor that compresses a flammable refrigerant, and that is capable of suppressing entry of a foreign substance such as gas or liquid into a terminal cover.
A compressor according to one aspect of the present disclosure is a compressor including: a compressor main unit that compresses a flammable refrigerant; a hermetic terminal that is provided to the compressor main unit and to which wiring providing external electrical connection is connected; a seal member that is provided on the outside of an outer surface of the compressor main unit; a terminal cover that is attached to the compressor main unit with the seal member interposed between the terminal cover and the compressor main unit, and that covers the hermetic terminal; and a plurality of fixing units that fix the terminal cover to the compressor main unit, in which the plurality of fixing units are provided at substantially symmetrical positions about the hermetic terminal.
The compressor according to the present disclosure has a sealed structure in which a hermetic terminal provided to a sealed container is covered by a terminal cover, and that is capable of suppressing entry of a foreign substance such as gas or liquid into the terminal cover.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a schematic diagram of a refrigeration cycle apparatus according to an exemplary embodiment of the present disclosure;

Fig. 2 is a perspective view of an upper part of the compressor at the time of assembly;
Fig. 3 is a plan view of the compressor at the time of assembly;
Fig. 4 is an exploded perspective view of the upper part of the compressor;
Fig. 5A is a cross-sectional view taken along line A-A in Fig. 3;
Fig. 5B is a schematic illustrating the hermetic terminal in Fig. 5A;
Fig. 5C is a schematic illustrating a body of the hermetic terminal in Fig. 5B;
Fig. 6 is a sectional view taken along line B-B in Fig. 3;
Fig. 7 is a plan view of the compressor on which a planar seal member is placed;
Fig. 8 is a plan view of the compressor with the seal member removed from Fig. 7;
Fig. 9 is a perspective view of the compressor with the seal member removed from Fig. 7;
Fig. 10A is a plan view of a grommet according to another exemplary embodiment;
Fig. 10B is a side view of the grommet according to the other exemplary embodiment;
Fig. 10C is a perspective view of the grommet according to the other exemplary embodiment; and
Fig. 10D is a perspective cross-sectional view of the grommet according to the other exemplary embodiment.

DETAILED DESCRIPTIONS

(Underlying knowledge and the like of present disclosure)

At the time when the inventors have arrived at the present disclosure, there have been a plurality of disclosures, as a preventive measure against the explosion of a compressor provided in an outdoor unit of a refrigeration cycle apparatus that uses a flammable refrigerant, on methods for ensuring airtightness of the space inside the terminal cover of the compressor. In such methods, the terminal cover is sealed by interposing a planar seal member between the terminal cover and a planar part of the outer surface of a sealed container on which a hermetic terminal of the compressor is fixed, and by providing a separate unit for sealing wiring, to the terminal cover. With this, even when the flammable refrigerant leaks from the refrigerant pipe or the like in the refrigeration cycle apparatus, the flammable refrigerant is prevented from coming into contact with the hermetic terminal inside the terminal cover, and the safety is improved.
The inventors have found a problem in the conventional configuration that, because the bolt for fixing the terminal cover to the sealed container is away from the center of the hermetic terminal, as the nut is fastened, the sealing surface of the terminal cover becomes separated from the planar seal member, and a gap is formed therebetween, in a part of the terminal cover far from the center of the terminal. This leads to a loss in the airtightness, subjecting the compressor to a risk of gas or liquid passage. To solve this problem, the inventors have made the subject of the present disclosure.
The present disclosure provides a compressor having a sealed structure in which a hermetic terminal provided to a sealed container is covered by a terminal cover, and capable of suppressing entry of a foreign substance such as gas or liquid into the terminal cover.
Some exemplary embodiments will be described below in detail with reference to the drawings. Note that descriptions in more detail than necessary are sometimes omitted. For example, detailed descriptions of well-known matters or redundant descriptions of substantially identical configurations may be omitted.
Note that the appended drawings and the following description are provided for those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter, as described in the appended claims in any way.

(First exemplary embodiment)

A first exemplary embodiment will be described below with reference to drawings.

[1-1. Configuration]

[1-1-1. Configuration of refrigeration cycle apparatus]

Fig. 1 is a schematic configuration diagram of refrigeration cycle apparatus 1 according to a first exemplary embodiment. In Fig. 1, the flows of the refrigerant are indicated by arrows in the solid lines or the broken lines for convenience of description.
Refrigeration cycle apparatus 1 according to the present exemplary embodiment is an air conditioner. Solid lines indicate a flow of refrigerant during a cooling operation, and the broken lines indicate a flow of the refrigerant during a heating operation.
As illustrated in Fig. 1, refrigeration cycle apparatus 1 includes indoor unit 10 disposed inside a room, and outdoor unit 20 disposed outside the room.
Indoor unit 10 includes indoor unit casing 11, indoor heat exchanger 12 disposed inside indoor unit casing 11 and exchanging heat with the indoor air, and crossflow fan 13 that generates a flow in the indoor air so that the indoor air pass through indoor heat exchanger 12.
Outdoor unit 20 includes outdoor unit casing 21, compressor 22 that is disposed inside outdoor unit casing 21 and compresses the refrigerant, four-way valve 26 that switches the direction in which the refrigerant flows, outdoor heat exchanger 23 that exchanges heat with the outdoor air, axial fan 24 that generates a flow in the outdoor air so that the outdoor air passes through outdoor heat exchanger 23, and expansion valve 25 that decompresses the refrigerant.
Refrigerant pipe 30 forms a refrigeration cycle by connecting compressor 22, four-way valve 26, outdoor heat exchanger 23, expansion valve 25, and indoor heat exchanger 12 in a loop-like shape.

[1-1-2. Configuration of assembly of compressor]

Fig. 2 is a perspective view of an upper part of compressor 22 according to the first exemplary embodiment at the time of assembly. Fig. 3 is a plan view of the upper part of compressor 22 at the time of assembly, and Fig. 4 is an exploded perspective view of the upper part of compressor 22 at the time of assembly. Fig. 5A is a cross-sectional view between fixing portions (A-A in Fig. 3) of the compressor at the time of assembly. Fig. 6 is a cross-sectional view of the compressor across the direction of wiring (B-B in Fig. 3) at the time of assembly. Fig. 7 is a plan view of the compressor set with seal member 45 placed thereon.

[1-1-3. Configuration of compressor]

Fig. 8 is a plan view of the compressor according to the first exemplary embodiment. Fig. 8 is different from Fig. 7 in that seal member 45 is removed.
Fig. 9 is a perspective view illustrating the upper part of compressor 22.
Compressor 22 according to the first exemplary embodiment illustrated in Figs. 2 to 9 is a rotary compressor. Casing 40 of compressor 22 is a sealed container, and has cylindrical compressor main unit 42 where a pump mechanism (not illustrated) that includes a compression chamber for compressing a refrigerant and a motor (not illustrated) for driving a rotor rotating in the compression chamber are housed. Top cap 43 closing the upper surface of compressor main unit 42 and a bottom cap (not illustrated) closing the lower surface are also provided.
Top cap 43 has a planar part and a curved part for purposes such as ensuring strength, and improving welding workability and the ease of assembly. The planar part is provided with refrigerant discharge pipe 51 through which refrigerant is discharged, fixing members 47, and hermetic terminal 44 that is electrically connected to the motor.
Refrigerant discharge pipe 51 is spatially connected to the compression chamber, and is brazed onto top cap 43.
As illustrated in Fig. 5B, hermetic terminal 44 is an electrode terminal fixed to body 44a, and fixed and sealed with insulating glass 44e that is insulating. The electrode terminal is terminal rod 44b to which terminal block 44c provided outside the sealed container and terminal block 44d provided inside the sealed container are connected, and provided with plating. Body 44a is a metal having a cylindrical shape. Terminal block 44d disposed inside the sealed container is electrically connected to a motor (not illustrated) installed inside compressor casing 40. This terminal block 44d is a part of the electrode terminal disposed inside compressor casing 40.
One example of fixing members 47 is stud bolts, and fixing members 47 are fixed by, for example, welding, to positions symmetrical to each other about hermetic terminal 44, in the planar part of top cap 43.
In the present exemplary embodiment, planar seal member 45 is provided. Planar seal member 45 has holes 53 provided in a manner avoiding the outer periphery of cylindrical portion 44h where hermetic terminal 44 on the planar part of top cap 43 is exposed to the outside of compressor casing 40, and the outer peripheries of the cylindrical portions on the bottom surfaces of respective stud bolts 47.
Cables 49a to 49c are connected to terminal block 44c of the electrode terminal on the outer side of the sealed container, via connection terminals 52a to 52c, respectively.
After passing cables 49a to 49c through a cable extraction hole on terminal cover 46, terminal cover 46 is disposed on seal member 45 so as to cover hermetic terminal 44 from above, and stud bolts 47 are fastened with nuts 48. In this manner, the space between top cap 43 of compressor 22 and terminal cover 46 can be sealed.
To terminal cover 46, cable gland body 50b of cable gland 50, with cable gland seal member 50a fitted thereto, is attached. Cables 49a to 49c are then passed through cable gland seal member 50c, and cable gland seal member 50c is attached to cable gland body 50b. By then fastening nut 50d for cable gland 50, the space between terminal cover 46, cable gland 50, and cables 49a to 49c can be sealed.
These cables 49a to 49c are then electrically connected to a control board, not illustrated, provided inside outdoor unit 20, with the airtightness with terminal cover 46 ensured by cable gland 50.

[1-2. Operation]

An operation of refrigeration cycle apparatus 1 configured as described above will be described below.
In the present exemplary embodiment, a flammable refrigerant is used as refrigerant to be circulated through the refrigerant circuit. Examples of the flammable refrigerant include R32, a mixed refrigerant containing R32 at 70 weight percent or more, propane, and a mixed refrigerant containing propane.
When refrigeration cycle apparatus 1 starts driving, compressor 22 is driven to compress the refrigerant, and axial fan 24 and crossflow fan 13 are rotated.
During the cooling operation, the refrigerant flows in the direction indicated by the arrows in the solid lines in Fig. 1. First, the refrigerant having been turned into high-temperature and high-pressure gas, by being compressed by compressor 22, passes through four-way valve 26, and sent to outdoor heat exchanger 23. Axial fan 24, generating a flow of the outdoor air passing through outdoor heat exchanger 23, causes the refrigerant to exchange heat with the outdoor air, so that the refrigerant is cooled and becomes condensed. The condensed refrigerant is then decompressed by expansion valve 25, exchanges heat with the indoor air in indoor heat exchanger 12, and evaporates. The refrigerant is turned into gas refrigerant by depriving the indoor air of the heat, and is returned to compressor 22.
During the heating operation, four-way valve 26 is switched so that the refrigerant flows in the direction indicated by the arrows in the broken lines in Fig. 1. First, the refrigerant having been turned into high-temperature and high-pressure gas, by being compressed by compressor 22, passes through four-way valve 26, and sent to indoor heat exchanger 12. Crossflow fan 13, generating a flow of the indoor air passing through indoor heat exchanger 12, causes the refrigerant to exchange heat with the indoor air, so that the refrigerant is cooled and becomes condensed. The condensed refrigerant is then decompressed by expansion valve 25, exchanges heat with the outdoor air in outdoor heat exchanger 23, and evaporates. The refrigerant is thus turned into gas refrigerant, and is returned to compressor 22.

(Other exemplary embodiments)

The first exemplary embodiment has been described above as an example of the technology disclosed in the present application. However, the technology according to the present disclosure is not limited to the exemplary embodiment described above, and may also be applied to exemplary embodiments in which change, substitution, addition, omission, and the like are made. In addition, new exemplary embodiments can be made by combining elements described in the first exemplary embodiment.
Such other exemplary embodiments will be described below.
In the first exemplary embodiment described above, the airtightness of terminal cover 46 with respect to cables 49a to 49c is ensured using cable gland 50, but the present invention is not limited thereto, and a dustproof and waterproof grommet 60 may also be used, as illustrated in Fig. 10A, for example.
Figs. 10A to 10D are a plan view, a side view, a perspective view, and a perspective cross-sectional view, respectively, of grommet 60 according to another exemplary embodiment.
Although it is necessary to change terminal cover 46 suitably to the configuration of the grommet, a description thereof is omitted herein.
In the first exemplary embodiment, an example in which the compressor according to the present disclosure is applied to an air conditioner has been described, as one exemplary embodiment. However, the present disclosure is also applicable to any refrigeration cycle apparatus that uses a flammable refrigerant, such as a heat pump water heater.

(Appendix)

(Technology 1) A compressor including: a compressor main unit that compresses a flammable refrigerant; a hermetic terminal that is provided to the compressor main unit and to which wiring providing external electrical connection is connected; a seal member that is provided on the outside of an outer surface of the compressor main unit; a terminal cover that is attached to the compressor main unit with the seal member interposed between the terminal cover and the compressor main unit, and that covers the hermetic terminal; and a plurality of fixing units that fix the terminal cover to the compressor main unit, in which the plurality of fixing units are provided at substantially symmetrical positions about the hermetic terminal.
With this configuration, it is possible to keep the peripheral edge of the terminal cover into closer contact with the seal member, and to prevent the terminal cover from partially separating from the seal member at the time when the fixing unit is fastened. Therefore, it is possible to improve the airtightness of the part exposed to the outside of the casing of the hermetic terminal of the compressor. Hence, in the refrigeration cycle apparatus using this configuration, it is possible to prevent entry of the refrigerant into the compressor.
(Technology 2) The compressor according to Technology 1, wherein the seal member has a substantially planar shape, and the hermetic terminal is provided to a top surface of the compressor main unit.
With this configuration, it is possible to easily seal the space between the seal member and the terminal cover, and to facilitate improvements in the airtightness of the portion of the hermetic terminal exposed to the outside of the compressor casing. Hence, it is possible to suppress entry of the refrigerant into the compressor using this configuration.
(Technology 3) In the compressor according to Technology 1 or 2, the compressor main unit has a planar part having a substantially planar shape, in a part of the top surface where the seal member is disposed.
With this configuration, it is possible to easily seal the space between the seal member and the plane where the hermetic terminal of the compressor is fixed, and it is possible to facilitate improvements in the airtightness of the portion of the hermetic terminal exposed to the outside of the compressor casing. Furthermore, by combining with (Technology 2), it is possible to further suppress entry of the refrigerant into the compressor using this configuration.
(Technology 4) The compressor according to Technology 1, in which the fixing units include a bolt having a first end welded and fixed to the compressor and a second end having a thread, and a nut attached to the thread.
With this configuration, because the terminal cover can be fixed with the bolt and the nut that are fixed at symmetrical positions with respect to the hermetic terminal therebetween, the load can be exerted more uniformly across the terminal cover, a partial detachment or a deformation of the terminal cover can be prevented. Therefore, it is possible to improve the airtightness of the portion of the hermetic terminal exposed to the outside of the compressor casing. Hence, it is possible to prevent entry of the refrigerant into the compressor using this configuration.
(Technology 5) The compressor according to Technology 4, in which the seal member is installed on a planar part of a top surface of the compressor main unit, and includes a planar part surrounding at least a cylindrical part of the hermetic terminal, and a hole through which the bolt passes, and the terminal cover as well as the seal member cover and seal the planar part of the compressor main unit.
With this configuration, the ease of attachment of the seal member to the compressor and of sealing of the terminal cover is improved. Therefore, it is possible to improve the airtightness of the part exposed to the outside of the casing of the hermetic terminal of the compressor. Hence, it is possible to suppress entry of the refrigerant into the compressor using this configuration.
(Technology 6) The compressor according to Technology 1, in which the terminal cover is configured to hold the wiring with a sealed state.
With this configuration, it is possible to seal the space between the terminal cover and the wiring, so that it is possible to improve the airtightness of the part exposed to the outside of the casing of the hermetic terminal of the compressor. Furthermore, with synergistic effect of Technologies 1 to 5, the airtightness is further improved.
Hence, it is possible to prevent entry of the refrigerant into the compressor using this configuration.
The present disclosure is applicable to a compressor having a sealed structure, a refrigeration cycle apparatus including a compressor, and a terminal cover used in the sealed structure.

Claims

A compressor comprising:
a compressor main unit that compresses a flammable refrigerant;

a hermetic terminal that is provided to the compressor main unit and to which wiring providing external electrical connection is connected;

a seal member that is provided on the outside of an outer surface of the compressor main unit;

a terminal cover that is attached to the compressor main unit with the seal member interposed between the terminal cover and the compressor main unit, and that covers the hermetic terminal; and

a plurality of fixing units that fix the terminal cover to the compressor main unit,

wherein the plurality of fixing units are provided at substantially symmetrical positions about the hermetic terminal.
The compressor according to Claim 1, wherein the seal member has a substantially planar shape, and the hermetic terminal is provided to a top surface of the compressor main unit.
The compressor according to Claim 1 or 2, wherein the compressor main unit has a planar part having a substantially planar shape, in a part of the top surface where the seal member is disposed.
The compressor according to Claim 1, wherein
at least one of the plurality of fixing units includes:
a bolt having a first end welded to the compressor main unit, and a second end having a thread;

and a nut attached to the thread.
The compressor according to Claim 4, wherein
the seal member is installed on a planar part of the compressor main unit, and includes a planar part surrounding at least a cylindrical part of the hermetic terminal, and a hole through which the bolt passes, and

the terminal cover as well as the seal member cover and seal the planar part of the compressor main unit.
The compressor according to Claim 1, wherein the terminal cover is configured to hold the wiring with a sealed state.