AU2023242477B2

AU2023242477B2 - Compressor and air conditioner

Info

Publication number: AU2023242477B2
Application number: AU2023242477A
Authority: AU
Inventors: Tatsuya Katayama; Daiki KIKUTAKE
Original assignee: Daikin Industries Ltd
Current assignee: Daikin Industries Ltd
Priority date: 2022-03-31
Filing date: 2023-03-23
Publication date: 2026-01-29
Anticipated expiration: 2043-03-23
Also published as: AU2023242477A1; JP2023152858A; WO2023190051A1; CN118575000A; JP7381975B2; EP4455485A1; US20240410601A1; EP4455485A4

Abstract

The dimensions of a casing (20) or a muffler (38) are set so that, across the entire range of a first resonance mode in which a resonance frequency changes due to changes on the oil surface of a lubricating oil stored in the casing (20), the resonance frequency of the first resonance mode differs from the resonance frequency of a second resonance mode in which the resonance frequency does not change due to changes on the oil surface of the lubricating oil.

Description

DESCRIPTION 29 Oct 2024 2023242477 29 Oct 2024

DESCRIPTION TITLE TITLE COMPRESSOR AND COMPRESSOR AND AIRCONDITIONER AIR CONDITIONER

55 2023242477

TECHNICALFIELD TECHNICAL FIELD

[0001]

The present disclosure relates to a compressor and an air conditioner.

10 BACKGROUNDART 10 BACKGROUND ART

[0002]

Some typical compressors include a muffler provided between a fluid outlet (discharge

port) of a compression mechanism in a casing and a high-pressure space in the casing (see, e.g.,

Patent Document 1).

15 [0003]

The compressor of Patent Document 1 employs a configuration allowing the resonance

frequency in the muffler to match the resonance frequency in the space between the muffler and

the casing in order to reduce noise.

20 CITATION 20 CITATIONLIST LIST

PATENT DOCUMENT PATENT DOCUMENT

[0004]

Patent Document 1: Japanese Utility Model Publication No. S55-17914

25 SUMMARY 25 SUMMARY

[0005] 04 Dec 2025

In general, a compressor has a first resonance mode where the resonance frequency

changes as the oil level of lubricant oil stored in a casing changes and a second resonance mode

where the resonance frequency does not change as the oil level of lubricant oil stored in a casing

5 changes. Then, a louder noise is produced if the resonance frequencies of the two resonance 2023242477

modes match each other due to fluctuation in the oil level of lubricant oil. However, the

compressor of Patent Document 1 does not take any measures against that noise into

consideration.

[0005a]

10 It is an object of the present invention to substantially overcome, or at least ameliorate,

one or more of disadvantages of existing arrangements, or provide a useful alternative.

[0006]

Some embodiments of the present disclosure are intended to reduce noise generated

by the resonance frequency of the first resonance mode and the resonance frequency of the

15 second resonance mode matching each other due to fluctuation in the oil level in a casing.

[0006a]

According to one aspect of the present disclosure, there is provided a compressor

including: a casing having a cylindrical shape and including end plates at both ends; a

compression mechanism housed in the casing; and a muffler disposed between a fluid outlet of

20 the compression mechanism and a space in the casing, wherein the compressor further

comprises an electric motor disposed above the compression mechanism and configured to

drive the compression mechanism, a resonance frequency of a first resonance mode is a

resonance frequency of which parameters are a volume of the muffler and a volume of a primary

space formed between a lower end of the electric motor and a bottom surface of the casing and

25 changing in accordance with an oil level, a resonance frequency of a second resonance mode is

46978429 2 a resonance frequency of which a parameter is an inner diameter of part of the casing forming 04 Dec 2025 the primary space, and a size of the casing or the muffler is set so that in an entire range of the first resonance mode where the resonance frequency changes as the oil level of lubricant oil stored in the casing changes, the resonance frequency of the first resonance mode is different

5 from the resonance frequency of the second resonance mode where the resonance frequency 2023242477

does not change as the oil level of the lubricant oil changes.

[0006b]

According to another aspect of the present disclosure, there is provided an air

conditioner including a refrigerant circuit configured to perform a vapor compression

10 refrigeration cycle, wherein the refrigerant circuit includes the compressor of the above aspect.

[0006c]

According to another aspect of the present disclosure, there is provided an air

refrigeration cycle, wherein a compressor of the refrigerant circuit includes a casing having a

15 cylindrical shape and including end plates at both ends, a compression mechanism housed in

the casing, and a muffler disposed between a fluid outlet of the compression mechanism and a

space in the casing; and has a first resonance mode where a resonance frequency changes as an

oil level of lubricant oil stored in the casing changes and a second resonance mode where the

resonance frequency does not change as the oil level of lubricant oil stored in the casing changes,

20 the compressor further comprises an electric motor disposed above the compression mechanism

and configured to drive the compression mechanism, a resonance frequency of a first resonance

mode is a resonance frequency of which parameters are a volume of the muffler and a volume

of a primary space formed between a lower end of the electric motor and a bottom surface of

the casing and changing in accordance with an oil level, a resonance frequency of a second

25 resonance mode is a resonance frequency of which a parameter is an inner diameter of part of

46978429 2a the casing forming the primary space, and the resonance frequency of the first resonance mode 04 Dec 2025 is lower than the resonance frequency of the second resonance mode at an oil level at which lubricant oil in the refrigerant circuit is collected in the compressor.

[0006d]

5 According to another aspect of the present disclosure, there is provided an air 2023242477

cylindrical shape and including end plates at both ends, a compression mechanism housed in

10 space in the casing; and has a first resonance mode where a resonance frequency changes as an

the compressor further comprises an electric motor disposed above the compression mechanism

15 mode is a resonance frequency of which parameters are a volume of the muffler and a volume

resonance mode is a resonance frequency of which a parameter is an inner diameter of part of

the casing forming the primary space, and the air conditioner operates to control an oil level of

20 the compressor so that the resonance frequency of the first resonance mode is lower than the

resonance frequency of the second resonance mode at all times during a steady operation in an

entire operation range.

[0006e]

According to another aspect of the present disclosure, there is provided an air conditioner

25 including a refrigerant circuit configured to perform a vapor compression refrigeration cycle,

46978429 2b wherein a compressor of the refrigerant circuit includes a casing having a cylindrical shape and 04 Dec 2025 including end plates at both ends, a compression mechanism housed in the casing, and a muffler disposed between a fluid outlet of the compression mechanism and a space in the casing; and has a first resonance mode where a resonance frequency changes as an oil level of lubricant oil

5 stored in the casing changes and a second resonance mode where the resonance frequency does 2023242477

not change as the oil level of lubricant oil stored in the casing changes, the compressor further

10 space formed between a lower end of the electric motor and a bottom surface of the casing and

changing in accordance with an oil level, a resonance frequency of a second resonance mode is

a resonance frequency of which a parameter is an inner diameter of part of the casing forming

the primary space, and the air conditioner operates to control an oil level of the compressor so

that the resonance frequency of the first resonance mode is higher than the resonance frequency

15 of the second resonance mode at all times during a steady operation in an entire operation range.

[0006f]

According to another aspect of the present disclosure, there is provided an air

20 cylindrical shape and including end plates at both ends, a compression mechanism housed in

25 the compressor further comprises an electric motor disposed above the compression mechanism

46978429 2c and configured to drive the compression mechanism, a resonance frequency of a first resonance 04 Dec 2025 mode is a resonance frequency of which parameters are a volume of the muffler and a volume of a primary space formed between a lower end of the electric motor and a bottom surface of the casing and changing in accordance with an oil level, a resonance frequency of a second

5 resonance mode is a resonance frequency of which a parameter is an inner diameter of part of 2023242477

the casing forming the primary space, and the air conditioner avoids an operation of the

compressor and does not perform a steady operation at a point at which the resonance

frequencies of the first resonance mode and the second resonance mode match each other.

[0007]

10 A first aspect of the present disclosure is directed to a compressor including: a casing

(20) having a cylindrical shape and including end plates (22, 23) at both ends; a compression

mechanism (30) housed in the casing (20); and a muffler (38) disposed between a fluid outlet

(32b) of the compression mechanism (30) and a space in the casing (20), wherein a size of the

casing (20) or the muffler (38) is set so that in an entire range of a first resonance mode where

15 a resonance frequency changes as an oil level of lubricant oil stored in the casing (20) changes,

the resonance frequency of the first resonance mode is different from a resonance frequency of

a second resonance mode where the resonance frequency does not change as the oil level of the

lubricant oil changes.

46978429 2d

[0008]

In the first aspect, the resonance frequency of the first resonance mode is different from In the first aspect, the resonance frequency of the first resonance mode is different from

the resonance the frequencyofofthe resonance frequency thesecond secondresonance resonance mode, mode, andand thus thus thethe twotwo resonance resonance modes modes do do

not overlap not overlap each eachother otherwhen whenthethe compressor compressor (10) (10) is operating. is operating. Thus, Thus, noisenoise increase increase can can be be

reduced. reduced.

[0009]

A second A secondaspect aspectofofthe thepresent presentdisclosure disclosureisisdirected directedtotothe thecompressor compressorof of thethe first first

aspect. The aspect. The compressor further includes compressor further includes an an electric electric motor motor (40) (40) disposed disposed above the compression above the compression

mechanism(30) mechanism (30)and andconfigured configuredtotodrive drive the the compression compressionmechanism mechanism (30),wherein (30), whereinthethe

resonancefrequency resonance frequencyofofthe thefirst first resonance resonance mode is aa resonance mode is frequencyofofwhich resonance frequency whichparameters parameters

are aa volume are of the volume of the muffler muffler (38) (38) and and a a volume of aa primary volume of space(60) primary space (60) formed formedbetween between a lower a lower

end ofof the end theelectric electric motor motor(40) (40)andand a bottom a bottom surface surface ofcasing of the the casing (20)changing (20) and and changing in in

accordancewith accordance withthe theoil oil level, level, and and the the resonance frequencyofofthe resonance frequency the second secondresonance resonancemode mode is is a a

resonance frequency of which a parameter is an inner diameter of part of the casing (20) forming resonance frequency of which a parameter is an inner diameter of part of the casing (20) forming

the primary space (60). the primary space (60).

[0010]

In the In the second secondaspect, aspect,overlapping overlappingof of thethe twotwo resonance resonance modesmodes which particularly which particularly

affects noise increase is reduced, and thus noise increase can be reduced. affects noise increase is reduced, and thus noise increase can be reduced.

[0011]

A third aspect of the present disclosure is directed to the compressor of the first or A third aspect of the present disclosure is directed to the compressor of the first or

secondaspect, second aspect, wherein whereinthe theresonance resonancefrequency frequency of of thefirst the first resonance resonancemode modeis is lower lower than than thethe

resonancefrequency resonance frequencyofofthe thesecond secondresonance resonance mode mode at an at an oiloil levelreached level reachedbyby anan amount amount of oil of oil

initially supplied into the casing (20). initially supplied into the casing (20).

[0012]

In the In the third third aspect, aspect, at at all all times during the times during theoperation operationofofthethecompressor compressor (10), (10), the the

3 resonancefrequency resonance frequencyofofthe thefirst first resonance modeisislower resonance mode lowerthan thanthe theresonance resonancefrequency frequency of of thethe secondresonance second resonancemode, mode, andand the the two two resonance resonance modes modes do not do not overlap overlap eachwhen each other other thewhen the compressor(10) compressor (10)isis operating. operating. Thus, noise increase Thus, noise increase can can be be reduced. reduced.

[0013]

A fourth aspect of the present disclosure is directed to the compressor of the first or A fourth aspect of the present disclosure is directed to the compressor of the first or

secondaspect, second aspect, wherein whereinthe theresonance resonancefrequency frequencyofof thefirst the first resonance resonancemode modeisishigher higherthan thanthe the

resonancefrequency resonance frequencyofofthe thesecond second resonance resonance mode mode with with no lubricant no lubricant oil being oil being stored stored in in the the

casing (20). casing (20).

[0014]

In the In the fourth fourth aspect, aspect, at at all all times during the times during the operation operationofofthe thecompressor compressor (10), (10), thethe

resonancefrequency resonance frequencyofofthe thefirst first resonance modeisishigher resonance mode higherthan thanthe the resonance resonancefrequency frequencyofofthe the

secondresonance second resonancemode, mode, andand the the two two resonance resonance modesmodes do not do not overlap overlap eachwhen each other other thewhen the

compressor(10) compressor (10)isis operating. operating. Thus, noise increase Thus, noise increase can can be be reduced. reduced.

[0015]

A fifth aspect of the present disclosure is directed to the compressor of any one of the A fifth aspect of the present disclosure is directed to the compressor of any one of the

first to first fourth aspects, to fourth aspects, wherein whereinthethe compression compression mechanism mechanism (30) is a(30) is a single-cylinder single-cylinder

compression mechanism. compression mechanism.

[0016]

In the In the fifth fifth aspect, aspect,thethecompressor compressor including including the single-cylinder the single-cylinder compression compression

mechanism mechanism does does notnot allow allow the the two two resonance resonance modes modes to overlap to overlap each and each other, other, thusand thus noise noise

increase can increase can be be reduced. reduced.

[0017]

A sixth aspect of the present disclosure is directed to an air conditioner comprising a A sixth aspect of the present disclosure is directed to an air conditioner comprising a

refrigerant circuit refrigerant circuitconfigured configuredto toperform perform aa vapor vapor compression refrigeration cycle, compression refrigeration cycle, wherein the wherein the

refrigerant circuit (1) includes the compressor (10) of any one of the first to fifth aspects. refrigerant circuit (1) includes the compressor (10) of any one of the first to fifth aspects.

4

[0018]

In the In the sixth sixth aspect, aspect, the the refrigeration refrigerationapparatus apparatusincluding including the thecompressor (10) of compressor (10) of any any

one of the first to fourth aspects can reduce the noise of the compressor (10) caused by the two one of the first to fourth aspects can reduce the noise of the compressor (10) caused by the two

resonancemodes resonance modesoverlapping overlapping each each other. other.

[0019]

A seventh aspect of the present disclosure is directed to an air conditioner comprising A seventh aspect of the present disclosure is directed to an air conditioner comprising

a refrigerant circuit (1) configured to perform a vapor compression refrigeration cycle, wherein a refrigerant circuit (1) configured to perform a vapor compression refrigeration cycle, wherein

a compressor (10) of the refrigerant circuit (1) includes a casing (20) having a cylindrical shape a compressor (10) of the refrigerant circuit (1) includes a casing (20) having a cylindrical shape

and including and including end endplates plates (22, (22, 23) 23) at at both both ends, ends, aa compression compressionmechanism mechanism (30)(30) housed housed in in the the

casing (20), casing (20), and andaamuffler muffler(38) (38)disposed disposed between between a fluid a fluid outlet outlet (32b) (32b) of compression of the the compression

mechanism mechanism (30) (30) andand a space a space in casing in the the casing (20); (20); anda has and has a resonance first first resonance modea mode where where a

resonancefrequency resonance frequencychanges changes as as an an oiloil levelofoflubricant level lubricantoil oil stored stored in in the the casing casing (20) (20) changes changes

and aa second and secondresonance resonancemode mode where where the the resonance resonance frequency frequency does does not change not change as theas thelevel oil oil level

of lubricant of lubricant oil oil stored stored in in the the casing (20) changes, casing (20) changes, and andthe theresonance resonance frequency frequency of the of the first first

resonancemode resonance modeisislower lowerthan thanthe theresonance resonancefrequency frequency of of thethe second second resonance resonance mode mode at anatoil an oil

level at which lubricant oil in the refrigerant circuit (1) is collected in the compressor (10). level at which lubricant oil in the refrigerant circuit (1) is collected in the compressor (10).

[0020]

In the seventh aspect, at all times during the operation, the resonance frequency of the In the seventh aspect, at all times during the operation, the resonance frequency of the

first resonance first resonancemode is lower mode is lower than than the theresonance resonance frequency frequency of of the thesecond second resonance resonance mode. Thus, mode. Thus,

noise increase noise increase caused causedbybythe theresonance resonancefrequencies frequencies of of thetwotwo the resonance resonance modes modes overlapping overlapping

each other each other can be reduced. can be reduced.

[0021]

An eighth aspect of the present disclosure is directed to an air conditioner comprising An eighth aspect of the present disclosure is directed to an air conditioner comprising

5 and including and including end endplates plates (22, (22, 23) 23) at at both both ends, ends, aa compression compressionmechanism mechanism (30)(30) housed housed in in the the casing (20), casing (20), and andaamuffler muffler(38) (38)disposed disposed between between a fluid a fluid outlet outlet (32b) (32b) of compression of the the compression mechanism mechanism (30) (30) andand a space a space in casing in the the casing (20); (20); anda has and has a resonance first first resonance modea mode where where a resonancefrequency resonance frequencychanges changes as as an an oiloil levelofoflubricant level lubricantoil oil stored stored in in the the casing casing (20) (20) changes changes and aa second and secondresonance resonancemode mode where where the the resonance resonance frequency frequency does does not change not change as theasoil thelevel oil level of lubricant oil stored in the casing (20) changes, and the air conditioner operates to control an of lubricant oil stored in the casing (20) changes, and the air conditioner operates to control an oil level of the compressor (10) so that the resonance frequency of the first resonance mode is oil level of the compressor (10) SO that the resonance frequency of the first resonance mode is lower than lower than the the resonance resonancefrequency frequencyofofthe thesecond secondresonance resonance mode mode at all at all times times during during a steady a steady operation in an entire operation range. operation in an entire operation range.

[0022]

In the In the eighth eighthaspect, aspect,the theair airconditioner conditioneroperates operates to to control control the the oil oil level level of of the the

compressor(10), compressor (10),and andthus thusthe theresonance resonancefrequency frequency of of thethe firstresonance first resonancemode mode is lower is lower thanthan

the resonance the frequencyofof the resonance frequency the second resonancemode second resonance modeat at alltimes. all times. Thus, Thus, noise noise increase increase caused caused

by the by the resonance frequencies of resonance frequencies of the the two two resonance resonance modes overlappingeach modes overlapping eachother othercan canbebereduced. reduced.

[0023]

A ninth aspect of the present disclosure is directed to an air conditioner comprising aa A ninth aspect of the present disclosure is directed to an air conditioner comprising

refrigerant circuit refrigerant circuit(1) configured (1) configuredtotoperform perform aavapor vapor compression refrigeration cycle, compression refrigeration cycle, wherein wherein

of lubricant oil stored in the casing (20) changes, and the air conditioner operates to control an of lubricant oil stored in the casing (20) changes, and the air conditioner operates to control an

oil level of the compressor (10) so that the resonance frequency of the first resonance mode is oil level of the compressor (10) SO that the resonance frequency of the first resonance mode is

6 higher than higher than the the resonance frequencyofofthe resonance frequency the second secondresonance resonancemode modeat at allalltimes timesduring duringa asteady steady operation in an entire operation range. operation in an entire operation range.

[0024]

In the In the ninth ninthaspect, aspect,the theairairconditioner conditioneroperates operates to control to control the the oil level oil level of of the the

compressor(10), compressor (10),and andthus thusthe theresonance resonancefrequency frequency of of thefirst the first resonance resonancemode modeis is higher higher than than

[0025]

A tenth aspect of the present disclosure is directed to an air conditioner comprising a A tenth aspect of the present disclosure is directed to an air conditioner comprising a

resonancefrequency resonance frequencychanges changesas as an an oiloil levelofoflubricant level lubricant oil oil stored stored in in the the casing casing (20) (20) changes changes

and aa second and secondresonance resonancemode mode where where the the resonance resonance frequency frequency does does not change not change as theasoil thelevel oil level

of lubricant oil stored in the casing (20) changes, and the air conditioner avoids an operation of of lubricant oil stored in the casing (20) changes, and the air conditioner avoids an operation of

the compressor the (10)and compressor (10) anddoes doesnot notperform performa asteady steadyoperation operationatata apoint pointat at which whichthe the resonance resonance

frequencies of the frequencies of the first firstresonance resonancemode mode and the second and the resonancemode second resonance mode match match each each other. other.

[0026]

In the tenth aspect, during an operation, the resonance frequencies of the two resonance In the tenth aspect, during an operation, the resonance frequencies of the two resonance

modesdodonotnotmatch modes match each each other other at any at any point. point. Thus, Thus, noise noise increase increase caused caused by thebyresonance the resonance

frequencies of frequencies of the the two two resonance modesoverlapping resonance modes overlapping each each other other cancan be be reduced. reduced.

[0027]

An eleventh aspect of the present disclosure is directed to the air conditioner of any An eleventh aspect of the present disclosure is directed to the air conditioner of any

7 one of the seventh to tenth aspects, wherein the compressor (10) includes an electric motor (40) one of the seventh to tenth aspects, wherein the compressor (10) includes an electric motor (40) disposed above disposed abovethethecompression compression mechanism mechanism (30)configured (30) and and configured to drivetothe drive the compression compression mechanism mechanism (30),the (30), theresonance resonancefrequency frequency of of thefirst the first resonance resonancemode modeisisa aresonance resonancefrequency frequency of which of parametersare which parameters area avolume volumeof of thethe muffler muffler (38) (38) andand a volume a volume of a of a primary primary spacespace (60) (60) formedbetween formed betweena alower lower end end of of theelectric the electricmotor motor(40) (40)and anda abottom bottomsurface surfaceofofthe thecasing casing(20) (20) and changing and changingininaccordance accordance with with the the oil oil level, level, andand the the resonance resonance frequency frequency of theofsecond the second resonancemode resonance modeisisa aresonance resonancefrequency frequency of of which which a parameter a parameter is an is an inner inner diameter diameter of part of part of of the casing the casing (20) (20) forming the primary forming the space(60). primary space (60).

[0028]

In the In the eleventh eleventh aspect, aspect, overlapping overlappingofofthe thetwo tworesonance resonance modes modes which which particularly particularly

[0029]

A twelfth aspect of the present disclosure is directed to the air conditioner of any one A twelfth aspect of the present disclosure is directed to the air conditioner of any one

of the eighth to eleventh aspects, wherein the air conditioner operates to control a rotational of the eighth to eleventh aspects, wherein the air conditioner operates to control a rotational

speed of speed of the the compressor compressor(10) (10)totoavoid avoida apoint pointatatwhich whichthetheresonance resonance frequencies frequencies of of thethe first first

resonancemode resonance modeandand the the second second resonance resonance mode each mode match match eachthereby other, other, controlling thereby controlling the the

resonancefrequency resonance frequencyofofthe thefirst first resonance resonance mode. mode.

[0030]

In the twelfth aspect, similarly to the ninth aspect, during an operation, the resonance In the twelfth aspect, similarly to the ninth aspect, during an operation, the resonance

frequencies of the frequencies of the two tworesonance resonancemodes modes do not do not match match each other each other at anyatpoint. any point. Thus, Thus, noise noise

increase caused increase caused by bythe theresonance resonancefrequencies frequencies of of thethe twotwo resonance resonance modes modes overlapping overlapping each each

other can other can be be reduced. reduced.

[0031]

A thirteenth aspect of the present disclosure is directed to the air conditioner of any A thirteenth aspect of the present disclosure is directed to the air conditioner of any

one of the eighth to eleventh aspects, wherein the air conditioner operates to adjust an amount one of the eighth to eleventh aspects, wherein the air conditioner operates to adjust an amount

8 of oil returned to the compressor (10) from an oil return circuit (6) including an oil separator of oil returned to the compressor (10) from an oil return circuit (6) including an oil separator

(7) (7) connected to aa discharge connected to discharge side side of of the the compressor compressor(10), (10),thereby therebycontrolling controllingthe theoil oillevel level to to

control the control the resonance frequencyof resonance frequency of the the first first resonance resonance mode. mode.

[0032]

In the thirteenth aspect, the oil return operation is performed to adjust the oil level, and In the thirteenth aspect, the oil return operation is performed to adjust the oil level, and

thus noise thus noise increase increase caused caused by the resonance by the resonance frequencies frequencies of of the the two two resonance resonance modes modes

overlappingeach overlapping eachother other can canbe bereduced. reduced.

[0033]

A fourteenth aspect of the present disclosure is directed to the air conditioner of any A fourteenth aspect of the present disclosure is directed to the air conditioner of any

one of the seventh to thirteenth aspects, wherein the compressor (10) is a compressor including one of the seventh to thirteenth aspects, wherein the compressor (10) is a compressor including

the single-cylinder the single-cylinder compression mechanism compression mechanism (30). (30).

[0034]

In the fourteenth aspect, the air conditioner including the refrigerant circuit including In the fourteenth aspect, the air conditioner including the refrigerant circuit including

the compressor the compressorhaving having thethe single-cylinder single-cylinder compression compression mechanism mechanism (30) can(30) cannoise reduce reduce noise

increase caused increase caused bybythe theresonance resonancefrequencies frequencies of of thethe twotwo resonance resonance modes modes overlapping overlapping each each

other. other.

[0035]

A fifteenth aspect of the present disclosure is directed to the air conditioner of the sixth A fifteenth aspect of the present disclosure is directed to the air conditioner of the sixth

or fourteenth or fourteenth aspect, aspect, wherein wherein a a rotational rotationalspeed speed N N (rps) (rps) of ofthe thecompression compression mechanism (30)isis mechanism (30)

120 ≤ N. 120 < N.

[0036]

In the In the fifteenth fifteenth aspect, aspect,the thecompressor (10) operating compressor (10) operating at at aa relatively relatively high high speed can speed can

reduce noise reduce noiseincrease increasecaused caused by by the the resonance resonance frequencies frequencies of the of twothe two resonance resonance modes modes

overlappingeach overlapping eachother. other.

9

BRIEF DESCRIPTION BRIEF DESCRIPTION OF OF THE THE DRAWINGS DRAWINGS

[0037]

FIG. 1 is a cross-sectional view of a compressor of a first embodiment. FIG. 1 is a cross-sectional view of a compressor of a first embodiment.

FIG. 22 is FIG. is aa formula formula for for determining a resonance determining a frequencyofofaa first resonance frequency first resonance resonance mode. mode.

FIG. 33 is FIG. is aaformula formulafor fordetermining determiningaaresonance resonance frequency frequency of of aasecond second resonance resonance mode. mode.

FIG.44 is FIG. is aa graph showinga arelationship graph showing relationship between betweena avolume volumeof of a primary a primary space space below below

an electric an electric motor motorand andresonance resonance frequencies frequencies of first of the the first resonance resonance mode mode and theand the second second

resonancemode. resonance mode.

FIG. 55 is FIG. is aa graph showinga arelationship graph showing relationshipbetween betweena avolume volume of of thethe primary primary space space and and

resonancefrequencies resonance frequenciesofofthe thefirst first resonance modeand resonance mode and thesecond the second resonance resonance modemode according according

the embodiment. the embodiment.

FIG. 66 is FIG. is aa graph showinga arelationship graph showing relationship between betweena avolume volumeof of thethe primary primary space space and and

resonancefrequencies resonance frequenciesofof the the first first resonance resonance mode andthe mode and thesecond secondresonance resonancemode mode according according a a

first variation of the first embodiment. first variation of the first embodiment.

FIG. 77 is FIG. is aa graph graph showing showinga avolume volumeof ofthetheprimary primary space space with with thethe resonance resonance

frequencies of the frequencies of the first firstresonance resonancemode mode and the second and the resonancemode second resonance mode matching matching each each other. other.

FIG.88illustrates FIG. illustrates an an operation of returning operation of returning oil oil to to a a compressor accordingto toa afirst compressor according first

variation of variation of aasecond second embodiment. embodiment.

DESCRIPTION OF DESCRIPTION OF EMBODIMENTS EMBODIMENTS

[0038]

Embodiments Embodiments will will be be described described in in detailwith detail withreference referencetoto the the drawings. drawings.

[0039]

A compressor A compressor(10) (10)ofofthis this embodiment embodiment is is a a compressor compressor (10) (10) of of oscillatingpiston oscillating pistontype type

and is and is connected connectedtotoa arefrigerant refrigerant circuit circuit (1) (1) as as shown shownininFIG. FIG.1. 1.TheThe refrigerant refrigerant circuit(1) circuit (1)

10 includes the includes the compressor compressor(10), (10),aaradiator radiator (2), (2), an an expansion mechanism expansion mechanism (3), (3), andand an an evaporator evaporator

(4), which (4), areconnected which are connected in sequence in sequence by a refrigerant by a refrigerant pipeand(5); pipe (5); and performs performs a vapor a vapor

compressionrefrigeration compression refrigeration cycle cycle by by aa refrigerant refrigerant circulating circulatingtherein. The therein. Theexpansion expansion mechanism mechanism

(3) is (3) is generally generally an expansionvalve an expansion valveofofwhich which thethe opening opening degree degree is adjustable, is adjustable, but but may may be be

another element such as a capillary tube of which the opening degree is fixed. another element such as a capillary tube of which the opening degree is fixed.

[0040]

Thecompressor The compressor (10) (10) includes includes a casing a casing (20). (20). TheThe casing casing (20) (20) is a is a closed closed container container

having a vertically long cylindrical shape and including a first end plate (22) at one end (upper having a vertically long cylindrical shape and including a first end plate (22) at one end (upper

end) and a second end plate (23) at the other end (lower end) of a cylindrical barrel (21) in the end) and a second end plate (23) at the other end (lower end) of a cylindrical barrel (21) in the

axial direction. axial direction. The casing(20) The casing (20)houses housesa compression a compression mechanism mechanism (30)compresses (30) that that compresses a a

refrigerant in the refrigerant circuit (1) and an electric motor (40) of variable-speed type that refrigerant in the refrigerant circuit (1) and an electric motor (40) of variable-speed type that

drives the drives the compression compression mechanism (30), where mechanism (30), the compression where the mechanism(30) compression mechanism (30)and andthe the

electric motor (40) are fixed to the inner peripheral surface of the barrel (21). the electric motor electric motor (40) are fixed to the inner peripheral surface of the barrel (21). the electric motor

(40) is disposed in the casing (20) in which a first space (S1) is sandwiched between the electric (40) is disposed in the casing (20) in which a first space (S1) is sandwiched between the electric

motor(40) motor (40) and andthe the first first end end plate plate(22), (22),and andthe compression the compression mechanism (30)isis disposed mechanism (30) disposedinin the the

casing (20) casing (20) in in which which aa second secondspace space(S2) (S2)isis sandwiched sandwiched between between thethe compression compression mechanism mechanism

(30) and the electric motor (40). (30) and the electric motor (40).

[0041]

Theelectric The electric motor motor(40) (40)includes includesa stator a stator(41) (41)andand a rotor a rotor (42), (42), both both formed formed in a in a

cylindrical shape. The stator (41) is fixed to the barrel (21) of the casing (20). The stator (41) cylindrical shape. The stator (41) is fixed to the barrel (21) of the casing (20). The stator (41)

includes a hollow portion where the rotor (42) is disposed. A drive shaft (45) is fixed to a hollow includes a hollow portion where the rotor (42) is disposed. A drive shaft (45) is fixed to a hollow

portion of the rotor (42) so as to penetrate the rotor (42), and the rotor (42) and the drive shaft portion of the rotor (42) SO as to penetrate the rotor (42), and the rotor (42) and the drive shaft

(45) rotates integrally. (45) rotates integrally.

[0042]

The drive shaft (45) includes a main shaft portion (46) extending vertically. The drive The drive shaft (45) includes a main shaft portion (46) extending vertically. The drive

11 shaft (45) is formed integrally with an eccentric portion (47) near a lower end of the main shaft shaft (45) is formed integrally with an eccentric portion (47) near a lower end of the main shaft portion (46). The eccentric portion (47) has a larger diameter than the main shaft portion (46). portion (46). The eccentric portion (47) has a larger diameter than the main shaft portion (46).

Theeccentric The eccentric portion portion (47) (47) has has an an axis axis decentered decentered by byaa predetermined predetermineddistance distancewith withrespect respecttoto

the axis of the main shaft portion (46). the axis of the main shaft portion (46).

[0043]

A lower end portion of the main shaft portion (46) is provided with an oil supply pump A lower end portion of the main shaft portion (46) is provided with an oil supply pump

(48). The (48). oil supply The oil pump(48) supply pump (48)isisimmersed immersedin in lubricant lubricant oiloil ininananoil oilreservoir reservoirformed formedatatthe the

bottomofofthe bottom the casing casing (20). (20). The oil supply The oil pump(48) supply pump (48)pumps pumpsup up lubricant lubricant oiloil intoananoil into oilsupply supply

path (not path (not shown) shown)ininthe thedrive driveshaft shaft (45) (45) along alongwith withrotation rotationofof the the drive drive shaft shaft (45), (45), and then and then

supplies the lubricant oil to each sliding portion of the compression mechanism (30). supplies the lubricant oil to each sliding portion of the compression mechanism (30).

[0044]

Thecompression The compressionmechanism mechanism (30)(30) includes includes a cylinder a cylinder (31) (31) formed formed in an in an annular annular shape. shape.

The cylinder (31) has one axial end (upper end) to which a front head (32) is fixed and the other The cylinder (31) has one axial end (upper end) to which a front head (32) is fixed and the other

axial end (lower end) to which a rear head (33) is fixed. The cylinder (31), the front head (32), axial end (lower end) to which a rear head (33) is fixed. The cylinder (31), the front head (32),

and the rear head (33) are stacked from top to bottom in order of the front head (32), the cylinder and the rear head (33) are stacked from top to bottom in order of the front head (32), the cylinder

(31), and the rear head (33), and are fastened and fixed together with a plurality of bolts, for (31), and the rear head (33), and are fastened and fixed together with a plurality of bolts, for

example.The example. Thecompression compression mechanism mechanism (30) (30) is is is what what is called called a single-cylinder a single-cylinder compression compression

mechanism mechanism including including one one cylinder cylinder andand oneone piston. piston.

[0045]

Thedrive The drive shaft shaft (45) (45) vertically verticallypenetrates penetratesthe thecompression compression mechanism (30).The mechanism (30). Thefront front

head (32) and the rear head (33) are provided with bearing portions (32a, 33a) that support the head (32) and the rear head (33) are provided with bearing portions (32a, 33a) that support the

drive shaft (45) at both above and below the eccentric portion (47). drive shaft (45) at both above and below the eccentric portion (47).

[0046]

The cylinder (31) has an upper end closed by the front head (32) and a lower end closed The cylinder (31) has an upper end closed by the front head (32) and a lower end closed

by the by the rear rear head (33). The head (33). internal space The internal of the space of the cylinder cylinder (31) (31) forms forms aa cylinder cylinder chamber chamber(35). (35).

12

Thecylinder The cylinder(31) (31)(cylinder (cylinderchamber chamber (35)) (35)) houses houses a tubular a tubular piston piston (34) (34) slidably slidably fittedtotothe fitted the

eccentric portion (47) of the drive shaft (45). As the drive shaft (45) rotates, the piston (34) eccentric portion (47) of the drive shaft (45). As the drive shaft (45) rotates, the piston (34)

rotates eccentrically in the cylinder chamber (35). Although not shown in the figure, the piston rotates eccentrically in the cylinder chamber (35). Although not shown in the figure, the piston

(34) hasananouter (34) has outerperipheral peripheral surface surface integrated integrated with with a blade a blade extending extending radiallyradially outward outward from the from the

outer peripheral surface of the piston (34). The blade is held by a bush (not shown) provided in outer peripheral surface of the piston (34). The blade is held by a bush (not shown) provided in

the piston the piston (34) (34) and and swings swingsalong alongwith withrotation rotationofofthe thedrive driveshaft shaft(45). (45).Thus, Thus,the thepiston piston(34) (34)

being rotated by itself is restricted. being rotated by itself is restricted.

[0047]

Thecylinder The cylinder (31) (31) has has aa suction suction port port (31a) (31a) communicating communicating with with thethe cylinder cylinder chamber chamber

(35). The suction port (31a) is connected with a suction pipe (36) fixed to the barrel (21). The (35). The suction port (31a) is connected with a suction pipe (36) fixed to the barrel (21). The

suction pipe (36) is connected with an accumulator (37) fixed to the casing (20). suction pipe (36) is connected with an accumulator (37) fixed to the casing (20).

[0048]

The front head (32) has a discharge port (32b) extending parallel to the axis of the drive The front head (32) has a discharge port (32b) extending parallel to the axis of the drive

shaft (45). shaft (45).The The discharge discharge port port (32b) (32b) is is opened opened and closed by and closed by aa discharge discharge valve valve(not (not shown). shown).AA

muffler (38) is attached to an upper surface of the front head (32) so as to cover the discharge muffler (38) is attached to an upper surface of the front head (32) SO as to cover the discharge

port (32b) port (32b) and andthethe discharge discharge valve. valve. A muffler A muffler space space (38a) defined (38a) defined in the (38) in the muffler muffler (38)

communicates communicates with with thethe internal internal space space of of thethe casing casing (20) (20) through through a discharge a discharge opening opening (38b) (38b)

formedononananupper formed upperportion portionofofthe the muffler muffler(38). (38).

[0049]

As described As describedabove, above, thethe suction suction pipe pipe (36)(36) connected connected to suction to the the suction port (31a) port (31a) is is

attached to the casing (20) so that a refrigerant is sucked into the compression mechanism (30) attached to the casing (20) SO that a refrigerant is sucked into the compression mechanism (30)

through the through the accumulator accumulator(37) (37)and andthe thesuction suctionpipe pipe(36). (36).

[0050]

A discharge pipe (39) is attached to the casing (20) and penetrates the first end plate A discharge pipe (39) is attached to the casing (20) and penetrates the first end plate

(22). (22). A lowerendend A lower portion portion of the of the discharge discharge pipeis(39) pipe (39) istoopen open the to the inside inside of the (20). of the casing casingThe(20). The

13 discharge port discharge port (32b) (32b) as as aa fluid fluid outlet outletof ofthe thecompression compression mechanism (30)communicates mechanism (30) communicates withwith the internal space of the casing (20) through the discharge opening (38b) of the muffler (38). A the internal space of the casing (20) through the discharge opening (38b) of the muffler (38). A refrigerant discharged refrigerant fromthe discharged from thecompression compression mechanism mechanism (30) flows (30) flows out of out the of the (20) casing casing (20) through the internal space of the casing (20) and the discharge pipe (39). through the internal space of the casing (20) and the discharge pipe (39).

[0051]

The first end plate (22) of the casing (20) is provided with a terminal (50) to which an The first end plate (22) of the casing (20) is provided with a terminal (50) to which an

electric wire for supplying electric power to the electric motor (40) is connected. electric wire for supplying electric power to the electric motor (40) is connected.

[0052]

As described As describedabove, above,thethecompressor compressor of this of this embodiment embodiment includes: includes: the casing the casing (20) (20)

having aa cylindrical having cylindrical shape and including shape and including the the end end plates plates (22, (22, 23) 23) at atboth both ends; ends; the thecompression compression

mechanism mechanism (30)housed (30) housed in in thecasing the casing(20); (20);and andthe themuffler muffler(38) (38) disposed disposedbetween betweenthe thedischarge discharge

port (32b) port (32b) of of the the compression mechanism compression mechanism (30) (30) andand thethe space space (second (second space space (S2)) (S2)) in in thethe casing casing

(20). (20).

[0053]

The compressor The compressor (10) (10) has has aa first first resonance resonance mode where the mode where the resonance resonance frequency frequency

changes as the oil level of lubricant oil stored in the casing (20) changes and a second resonance changes as the oil level of lubricant oil stored in the casing (20) changes and a second resonance

modewhere mode where theresonance the resonance frequency frequency does does not not change change as the as the oil oil level level of of lubricantoil lubricant oilstored stored in in

the casing the (20) changes. casing (20) changes. The Thecompressor compressor (10) (10) includes includes thethe casing casing (20) (20) and and the the muffler muffler (38), (38),

each of which has a size and shape defined so that in an entire range of the first resonance mode, each of which has a size and shape defined SO that in an entire range of the first resonance mode,

a resonance frequency f of the first resonance mode is different from a resonance frequency f2 a resonance frequency f1 of 1the first resonance mode is different from a resonance frequency f2

of the of the second second resonance mode. resonance mode.

[0054]

Theresonance The resonancefrequency frequency f1 fof 1 of thefirst the first resonance resonancemode modeis is a resonance a resonance frequency frequency of of

whichmain which mainparameters parameters areare a volume a volume of the of the muffler muffler and and a volume a volume ofprimary of the the primary space space (60), (60),

and is and is determined determinedbybythe theformula formula shown shown in FIG. in FIG. 2. Here, 2. Here, the primary the primary spacespace (60) (60) is is a space a space

14 formedbetween formed between thelower the lower end end of of thethe electricmotor electric motor(40) (40)and and thebottom the bottom surface surface of of thethe casing casing

(20) and (20) changinginin accordance and changing accordancewith withthe theoil oillevel. level. The primaryspace The primary spaceisis aa space space for for removing removing

oil accumulated in the casing (20). Thus, as the oil level in the casing (20) changes, the volume oil accumulated in the casing (20). Thus, as the oil level in the casing (20) changes, the volume

of the of the primary space(60) primary space (60)also alsochanges. changes.The The volume volume of the of the primary primary spacespace (60) includes (60) includes the the

volume of a space below the electric motor (40) and the volume of a space below the front head. volume of a space below the electric motor (40) and the volume of a space below the front head.

In the In the first firstresonance resonance mode, mode, the the resonance frequencyf1f1 changes resonance frequency changesasasthe thevolume volumeof of theprimary the primary

space (60) changes due to change in the oil level with respect to the area of a discharge opening space (60) changes due to change in the oil level with respect to the area of a discharge opening

and the and the length length of of aa discharge discharge opening openingofofthe themuffler muffler(38) (38)and andthe thevolume volumeof of a space a space (second (second

space (S2)) space (S2)) below belowthe theelectric electric motor, each determined motor, each determinedfor foreach eachcompressor compressor (10). (10). Specifically, Specifically,

as shown as shown ininthe thegraph graphofofFIG. FIG.4,4,the theresonance resonance frequency frequency f1 decreases f1 decreases as the as the volume volume of of the the

primaryspace primary space(60) (60)increases increasesdue duetotolowering loweringofofthe theoil oillevel, level, and and the the resonance resonancefrequency frequencyf1f1

increases as the volume of the primary space (60) decreases due to rising of the oil level. increases as the volume of the primary space (60) decreases due to rising of the oil level.

[0055]

Theresonance The resonancefrequency frequency f2 fof 2 of thesecond the second resonance resonance modemode is a is a resonance resonance frequency frequency

generated in generated in the the cross cross section section of of the the casing casing (20), (20), and and is is determined by the determined by the formula formulashown shownin in

FIG. 33 of FIG. of which whichaamain mainparameter parameterisisananinner innerdiameter diameterofofthe thecasing casing(20) (20)ininthe the space space(second (second

space (S2)) below the electric motor. In other words, a parameter of the resonance frequency f2 space (S2)) below the electric motor. In other words, a parameter of the resonance frequency f2

of the second resonance mode is an inner diameter of part of the casing (20) forming the primary of the second resonance mode is an inner diameter of part of the casing (20) forming the primary

space (60). space (60). To be exact, To be exact, aa value of the value of the resonance frequencyf2f2ofof the resonance frequency the second secondresonance resonancemode mode

slightly changes slightly in accordance changes in accordance with with thethe state state of the of the volume volume below below the head the front front(or head in (or in

accordance with the change in the oil level), and is inversely proportional to the inner diameter accordance with the change in the oil level), and is inversely proportional to the inner diameter

of the casing (20) and is substantially constant as shown in the graph of FIG. 4. of the casing (20) and is substantially constant as shown in the graph of FIG. 4.

[0056]

In FIG. In 2, Ap FIG. 2, is an Ap is an area area of of the the discharge opening(38b) discharge opening (38b)ofofthe themuffler muffler(38), (38), Lp Lpisis an an

axial length axial length of of the the discharge discharge opening (38b)of opening (38b) of the the muffler muffler (38) (38) of of which whichthe theopening openingendend areare

15 corrected, V corrected, V11 is is aavolume of the volume of the primary space (60), primary space (60), Vm Vm isisaa volume volumeofofthe themuffler, muffler,and andisβ ais a correction coefficient. The length Lp of the discharge opening (38) of which the opening end is correction coefficient. The length Lp of the discharge opening (38) of which the opening end is corrected is corrected is determined determinedbybyLength Length of Discharge of Discharge Opening Opening = Plate= Thickness Plate Thickness of +Muffler of Muffler +

(Correction Coefficient (Correction Coefficient of of Opening EndX ×Hydraulic Opening End Hydraulic Diameter Diameter of (One) of (One) Discharge Discharge Opening Opening of of

Muffler). The correction coefficient of an opening end is used to correct a deviation between a Muffler). The correction coefficient of an opening end is used to correct a deviation between a

position of the opening end of the muffler (38) and a position of a belly of the sound wave. In position of the opening end of the muffler (38) and a position of a belly of the sound wave. In

general, the value of the correction coefficient of an opening end is 0.3, and the correction value general, the value of the correction coefficient of an opening end is 0.3, and the correction value

is 0.3d is 0.3d where the diameter where the diameter (hydraulic (hydraulic diameter) diameter)of of the the discharge discharge opening opening(38b) (38b)ofofthe themuffler muffler

(38) is d. (38) is d. The correctioncoefficient The correction coefficient is βa is a value value determined determined by matching by matching a finitemethod a finite element element method

(FEM) analysisand (FEM) analysis andananactual actualmeasurement. measurement.

[0057]

In this In this embodiment, theresonance embodiment, the resonancefrequency frequency f1 fof 1 of thefirst the first resonance resonancemode modeis is about about

1027 Hz,where 1027 Hz, wherethe thesound soundspeed speed C c isis243 243(m/s), (m/s),assuming assumingananexample example where where the the areaarea Ap Ap of the of the

discharge opening (38b) of the muffler (38) is 5.84 X 10-5 (m ², −5 2 discharge opening (38b) of the muffler (38) is 5.84 × 10 (m ), the length Lp of the discharge the length Lp of the discharge

opening(38b) opening (38b)ofof which whichthe theopening openingend end isiscorrected correctedisis 2.83 10−3(m), 2.83 X×10-3 (m), the the volume volumeVmVm of of thethe

−5 (m³), muffler is muffler is 2.32 2.32 × X 10 10-5 (m3), the the volume V1ofofthe volume V1 theprimary primaryspace space(60) (60)isis1.90 10−4(m³), 1.90X×10-4 (m3),and and

the correction coefficient β is 0.84. the correction coefficient is 0.84.

[0058]

In FIG. In FIG. 3,3, the the correction correctioncoefficient coefficient aαisis aa value valuedetermined determinedby by matching matching a FEMa FEM

analysis analysis and and aa actual actual measurement, measurement,thethe mode mode coefficient coefficient a isλ aisconstant a constant determined determined by the by the

secondresonance second resonancemode, mode,andand R1 R is1 is a radiusofofthe a radius theinner innercircumferential circumferentialsurface surfaceofof the the body. body. In In

the example, the the resonance example, the frequencyf2f2 of resonance frequency of the the second second resonance modeisisabout resonance mode about1154 1154Hz, Hz,where where

the correction coefficient α is 0.73, the mode coefficient λ is 1.84, the radius R1 is 4.5 × 10−2 the correction coefficient a is 0.73, the mode coefficient a is 1.84, the radius R1 is 4.5 X 10-2

(m), and the sound speed c is 243 (m/s). (m), and the sound speed C is 243 (m/s).

[0059]

16

Onthe On the other other hand, hand, in in aa typical typicalcompressor (as aa comparative compressor (as example),the comparative example), theresonance resonance

frequencyf1 frequency f1 of of the the first firstresonance resonancemode is about mode is about 1160 Hz, where, 1160 Hz, where,for for example, example,the thearea areaAp Apofof −5 the 2length Lp of the discharge opening the discharge opening of the muffler is 4.75 × 10 (m ), the length Lp of the discharge opening the discharge opening of the muffler is 4.75 X 10-5 (m ²,

−3 (m), the volume Vm of the muffler is 1.55 of which of the opening which the openingend endisis corrected corrected is is 2.65 2.65 × X 10 10-3 (m), the volume Vm of the muffler is 1.55 −5 (m³),

× 10 10-5 (m3), the the volume volumeV1Vof 1 of thethe primary primary space space (60) (60) is 1.56 is 1.56 X 10 × 10−4the (m³), 3 (mcorrection ), the correction

coefficient βisis0.84, coefficient 0.84,and andthethesound sound speed speed C isc 243 is 243 (m/s). (m/s). In comparative In the the comparative example, example, the the

resonancefrequency resonance frequencyf2f2ofof the the second secondresonance resonancemode mode is is about about 1154 1154 Hz similarly Hz similarly to the to the above above

example, where the correction coefficient α is 0.73, the mode coefficient λ is 1.84, the radius example, where the correction coefficient a is 0.73, the mode coefficient a is 1.84, the radius

R1 is 4.5 X 10-2−2(m) similarly to the above example, and the sound speed C is 243 (m/s). R1 is 4.5 × 10 (m) similarly to the above example, and the sound speed c is 243 (m/s).

[0060]

As described As described above, above,this this embodiment exhibitsaalarge embodiment exhibits large difference difference between the resonance between the resonance

frequency frequency f1f1 ofof thefirst the firstresonance resonance mode mode andresonance and the the resonance frequency frequency f2 of the fsecond 2 of the second resonance resonance

mode,while mode, whilethethe typical typical compressor compressor exhibits exhibits a difference a small small difference between between the the resonance resonance

frequency f of the first resonance mode and the resonance frequency f of the second resonance frequency f1 1 of the first resonance mode and the resonance frequency f2 of the second 2 resonance

mode. Thus, in the typical compressor, if the resonance frequency f of the first resonance mode mode. Thus, in the typical compressor, if the resonance frequency f1 of the 1first resonance mode

fluctuates, the resonance fluctuates, the resonance frequencies frequencies of two of the the resonance two resonance modes modes are are likely to likely to match match each other.each other.

[0061]

If as If as shown in FIG. shown in FIG. 44 the the resonance resonancefrequency frequencyf1f1ofofthe thefirst first resonance modeand resonance mode andthe the

resonancefrequency resonance frequencyf2f2ofofthe the second secondresonance resonance mode mode match match each each otherother at point, at any any point, the the two two

resonancemodes resonance modes overlapping overlapping each each other other causes causes amplification amplification of sound, of the the sound, thereby thereby causing causing

noise increase. noise increase.

[0062]

In this embodiment, as described above, the size of the casing (20) or the muffler (38) In this embodiment, as described above, the size of the casing (20) or the muffler (38)

is set is set so SO that that the the resonance frequencyf1f1ofofthe resonance frequency thefirst first resonance resonancemode mode is different is different from from the the

resonancefrequency resonance frequencyf2f2of of the the second secondresonance resonancemode modein in theentire the entirerange rangeofofthe thefirst first resonance resonance

17 17 mode,and mode, andthus thusthe thetwo tworesonance resonancemodes modes do do notnot overlap overlap each each other. other.

[0063]

Specifically, in the compressor (10) of the first embodiment, the size of the casing (20) Specifically, in the compressor (10) of the first embodiment, the size of the casing (20)

or the or the muffler muffler (38) (38) is isdetermined determined so SO that that as asshown in FIG. shown in FIG. 55 the the resonance frequencyf1f1of resonance frequency of the the

first resonance first resonance mode is lower mode is lower than than the the resonance frequencyf2 resonance frequency f2 of of the the second second resonance modeatat resonance mode

the oil level reached by the amount of oil initially supplied into the casing (20). Specifically, the oil level reached by the amount of oil initially supplied into the casing (20). Specifically,

for example, for example, a adiameter diameterofofthethedischarge discharge opening opening of the of the muffler, muffler, the number the number of discharge of discharge

openings of the muffler, an area of the discharge opening of the muffler, a plate thickness of the openings of the muffler, an area of the discharge opening of the muffler, a plate thickness of the

muffler, a volume of the muffler space (38a), an inner diameter of the barrel (21), a volume of muffler, a volume of the muffler space (38a), an inner diameter of the barrel (21), a volume of

the primary space (60), and the like are determined so that f < f holds true as described in the the primary space (60), and the like are determined SO that f1 < f2 holds 1 2true as described in the

aboveembodiment. above embodiment.If If theparameters the parameters shown shown in the in the formulas formulas of FIGS. of FIGS. 2 and 2 and 3 are 3 are set set SO so thatf1f1 that

< f holds true at the oil level reached by the amount of oil initially supplied, f < f holds true < f22 holds true at the oil level reached by the amount of oil initially supplied, f1 < f2 1 holds2true

at all at all times times during during an operation of an operation of the the compressor compressor(10). (10).AsAs a result,atatall a result, all times timesduring duringthe the

operation, the operation, the resonance frequencyf1 resonance frequency f1 of of the the first firstresonance resonancemode mode and the resonance and the frequency resonance frequency

f2 of f2 of the thesecond second resonance modedodonot resonance mode notmatch match each each other other at at anypoint, any point,and andthus thusnoise noiseincrease increase

caused by caused bythe the two tworesonance resonancemodes modes overlapping overlapping each each other other cancan be reduced. be reduced.

[0064]

When operating at a high speed (e.g., where the rotational speed N (rps) during a steady When operating at a high speed (e.g., where the rotational speed N (rps) during a steady

operation is 120 ≤ N), a compressor undergoes an oil loss such that there is significant change operation is 120 < N), a compressor undergoes an oil loss such that there is significant change

in the oil level reached by the amount of oil initially supplied. Thus the compressor (10) that do in the oil level reached by the amount of oil initially supplied. Thus the compressor (10) that do

not allow not allow the thetwo tworesonance resonance modes modes to overlap to overlap each each other other is useful is more more useful in one in one preferred preferred

embodiment. In other words, a typical compressor operating at a high speed causes the oil level embodiment. In other words, a typical compressor operating at a high speed causes the oil level

to lower, to lower, thereby thereby allowing the two allowing the resonancemodes two resonance modesto to overlapeach overlap each other,but other, butthe thecompressor compressor

of this of this embodiment embodiment dodo notallow not allow them them to overlap to overlap eacheach other other eveneven whenwhen thelevel the oil oil level lowers, lowers,

thereby easily operating at a high speed. thereby easily operating at a high speed.

18

[0065]

–AdvantagesofofFirst -Advantages FirstEmbodiment- Embodiment–

Thecompressor The compressor (10) (10) operating operating at aathigh a high speed speed tendstends to allow to allow the casing the casing (20) to(20) to

discharge discharge a a larger larger amount amount ofSOoilthat of oil so the thatoilthelevel oil lowers. level lowers. In addition, In addition, if the(20) if the casing casing is (20) is

downsized and has a smaller diameter, the oil level significantly fluctuates as the amount of oil downsized and has a smaller diameter, the oil level significantly fluctuates as the amount of oil

changes. Thus, typically, the resonance frequency of the first resonance mode and the resonance changes. Thus, typically, the resonance frequency of the first resonance mode and the resonance

frequency of the frequency of the second resonancemode second resonance modeareare likelytotomatch likely matcheach eachother. other.

[0066]

In this embodiment, the size and shape of the casing (20) or the muffler (38) are set so In this embodiment, the size and shape of the casing (20) or the muffler (38) are set SO

that the that resonancefrequency the resonance frequencyof of thethe firstresonance first resonance mode mode is different is different from from the resonance the resonance

frequencyofofthe frequency thesecond secondresonance resonance mode. mode. Accordingly, Accordingly, even even if theifoil thelevel oil level fluctuates, fluctuates, the the

resonancefrequencies resonance frequenciesofofthethetwotwo resonance resonance modesmodes do notdo not each match match eachThus, other. other. Thus, noise noise

increase caused increase caused by by the the two two resonance modesoverlapping resonance modes overlappingeach eachother othercan canbebereduced. reduced.InInaddition, addition,

even if the oil level easily fluctuates by the compressor (10) being downsized and operated at a even if the oil level easily fluctuates by the compressor (10) being downsized and operated at a

high speed, high speed, the the two resonancemodes two resonance modesdodo notoverlap not overlap each each other,and other, andthus thusnoise noiseincrease increasecan canbebe

reduced. This reduced. This embodiment embodiment hashas a great a great advantage advantage in in reducing reducing thethe noise noise even even if the if the compressor compressor

is not is not downsized andoperated downsized and operatedatat aa high high speed. speed.

[0067]

–Variation of -Variation of First FirstEmbodiment– Embodiment-

According to a compressor of a first variation, the sizes and shapes of parts such as a According to a compressor of a first variation, the sizes and shapes of parts such as a

diameter of diameter of aa discharge discharge opening of aa muffler, opening of muffler, the the number of discharge number of discharge openings openingsofofthe themuffler, muffler,

an area of the discharge opening of the muffler, a plate thickness of the muffler, a volume of a an area of the discharge opening of the muffler, a plate thickness of the muffler, a volume of a

muffler space muffler space (38a), (38a), an an inner inner diameter of aa barrel diameter of barrel (21), (21),aavolume volume of of aa primary space (60), primary space (60), and and

the like are determined so that with no lubricant oil being stored in a casing (20), a resonance the like are determined SO that with no lubricant oil being stored in a casing (20), a resonance

19 frequencyofofthe frequency thefirst first resonance resonancemode modeis is higher higher than than a resonance a resonance frequency frequency of theofsecond the second resonancemode, resonance mode,asasshown shownin in FIG. FIG. 6. 6. IfIfthe the parameters parametersshown shownin in theformulas the formulasofof FIGS. FIGS. 2 and 2 and 3 3 are set so that f > f holds true where no oil is stored in the casing(20), f > f holds true at all are set SO that f11 > f22 holds true where no oil is stored in the casing(20 f1 > f2 holds 1 2true at all times because times becausethe the resonance resonancefrequency frequencyf1f1further furtherincreases increaseswhen whenananoiloillevel levelis is formed formedduring during a normal a operationofofthe normal operation thecompressor compressor (10).AsAs (10). a result,atatall a result, all times times during during the the operation, operation, the the resonance frequency f of the first resonance mode and the resonance frequency f of the second resonance frequency f1 of1the first resonance mode and the resonance frequency f2 of the second 2 resonancemode resonance modedo do notnot match match eacheach other other at any at any point, point, and and thusthus noise noise increase increase caused caused by by the the two resonance two resonancemodes modes overlapping overlapping each each other other cancan be be reduced. reduced.

[0068]

<<Second Embodiment>> <<Second Embodiment>>

A second A secondembodiment embodiment will will be be described described below. below.

[0069]

The second embodiment relates to an air conditioner including a refrigerant circuit (1). The second embodiment relates to an air conditioner including a refrigerant circuit (1).

Similarly to the above descriptions, a compressor (10) of the air conditioner includes: a casing Similarly to the above descriptions, a compressor (10) of the air conditioner includes: a casing

(20) having (20) having aa cylindrical cylindrical shape and including shape and including end endplates plates (22, (22, 23) 23) at at both both ends; ends; a a compression compression

mechanism mechanism (30) (30) housed housed in aincasing a casing (20); (20); andand a muffler a muffler (38)(38) disposed disposed between between a fluid a fluid outlet outlet

(32b) of (32b) of the the compression mechanism compression mechanism (30) (30) andand a space a space in in thethe casing casing (20).The (20). The compressor compressor (10)(10)

has aa first has firstresonance resonance mode wherethe mode where theresonance resonancefrequency frequency changes changes as as thethe oillevel oil levelofoflubricant lubricant

oil stored oil in the stored in the casing casing (20) (20)changes changesandand a second a second resonance resonance modethe mode where where the resonance resonance

frequency does not change as the oil level of lubricant oil stored in the casing (20) changes. frequency does not change as the oil level of lubricant oil stored in the casing (20) changes.

[0070]

In the air conditioner, the amount of oil and the length of pipe in the refrigerant circuit In the air conditioner, the amount of oil and the length of pipe in the refrigerant circuit

(1) (1) are determined are determined SO so that that thethe resonance resonance frequency frequency of the of theresonance first first resonance modethan mode is lower is lower the than the

resonance frequency of the second resonance mode at the oil level at which lubricant oil in the resonance frequency of the second resonance mode at the oil level at which lubricant oil in the

refrigerant circuit (1) is collected in the compressor (10). In the second embodiment, the sizes refrigerant circuit (1) is collected in the compressor (10). In the second embodiment, the sizes

20 of the casing (20) and the muffler (38) of the compressor (10) are not necessarily set so that the of the casing (20) and the muffler (38) of the compressor (10) are not necessarily set SO that the resonancefrequency resonance frequencyofofthe thefirst first resonance modeisisdifferent resonance mode different from fromthe theresonance resonancefrequency frequency of of the second the secondresonance resonancemode, mode, but but the the use use of compressor of the the compressor of theof the embodiment first first embodiment is not is not excluded. excluded.

[0071]

Also in Also in the the second second embodiment, theresonance embodiment, the resonancefrequency frequencyf1f1of ofthe the first first resonance resonance mode mode

is lower is lower than than the the resonance frequencyf2f2ofof the resonance frequency the second secondresonance resonancemode mode whenwhen the level the oil oil level of of

lubricant oil lubricant oil is is at atthe thehighest highest one, one, and thus similarly and thus similarly to to the exampleshown the example shownin in FIG. FIG. 5, the 5, the

resonance frequencies f and f do not match each other at any point during the operation. If as resonance frequencies f1 and 1 f2 do 2not match each other at any point during the operation. If as

shownininFIG. shown FIG.7 7the theresonance resonance frequencies frequencies f1 fand 1 and f2 fof 2 of thetwo the tworesonance resonance modes modes match match each each

other at any point, the noise increases, but according to the second embodiment, noise increase other at any point, the noise increases, but according to the second embodiment, noise increase

caused by caused bythe theresonance resonancefrequencies frequenciesf1f1and andf2f2ofofthe thetwo tworesonance resonance modes modes overlapping overlapping each each

other can other can be be reduced. reduced.

[0072]

–Variations of -Variations of Second Embodiment– Second Embodiment-

Similarly to the second embodiment, an air conditioner of a first variation includes a Similarly to the second embodiment, an air conditioner of a first variation includes a

refrigerant circuit refrigerant circuit (1) (1)including including aa compressor havinga first compressor having a firstresonance resonancemode mode and and a second a second

resonancemode. resonance mode.

[0073]

The air conditioner operates to control the oil level of a compressor (10) so that the The air conditioner operates to control the oil level of a compressor (10) SO that the

resonancefrequency resonance frequencyofofthe thefirst first resonance modeisislower resonance mode lowerthan thanthe theresonance resonance frequency frequency of of thethe

second resonance mode at all times during a steady operation in the entire operation range. second resonance mode at all times during a steady operation in the entire operation range.

[0074]

Specifically, as shown in FIG. 8, an oil return circuit (6) in the refrigerant circuit (1) is Specifically, as shown in FIG. 8, an oil return circuit (6) in the refrigerant circuit (1) is

21 used to adjust the amount of oil returned to the compressor (10). used to adjust the amount of oil returned to the compressor (10).

[0075]

Thecompressor The compressor(10) (10)isisprovided providedwith withananoil oillevel level gauge gauge(not (not shown) shown)for fordetecting detectingthe the

oil level. The oil return circuit (6) includes an oil separator (7) connected to the discharge side oil level. The oil return circuit (6) includes an oil separator (7) connected to the discharge side

of the of the compressor (10)and compressor (10) andincludes includesananoil oilreturn returnpipe pipe(7a) (7a) connected connectedtotoa asuction suctionpipe pipe(37a) (37a)

provided between provided betweenan an accumulator accumulator (37)(37) and and the compressor the compressor (10). (10). Thereturn The oil oil return pipe is(7a) pipe (7a) is

providedwith provided withananoiloilreturn returnvalve valve(7b). (7b).TheThe oiloil return return valve valve (7b)(7b) may may be anbe an on-off on-off valve valve

adjustable between two positions, i.e., a fully closed position and a fully open position, or may adjustable between two positions, i.e., a fully closed position and a fully open position, or may

be an be an opening openingdegree degreecontrol controlvalve valveadjustable adjustable to to any any opening openingdegree. degree.

[0076]

In the oil return operation, the rotational speed of the compressor (10) is increased to In the oil return operation, the rotational speed of the compressor (10) is increased to

increase the amount of refrigerant circulated, and the oil return valve (7b) is opened to collect increase the amount of refrigerant circulated, and the oil return valve (7b) is opened to collect

the oil in the refrigerant circuit (1). As the rotational speed of the compressor (10) increases, the oil in the refrigerant circuit (1). As the rotational speed of the compressor (10) increases,

the amount the amount ofofoil oil loss loss (the (the amount amountofofoil oil flowing flowingout outofofthe thecompressor compressor (10)) (10)) increases,andand increases,

thus, in general, the rotational speed is set to a medium speed in order to reduce the oil loss. In thus, in general, the rotational speed is set to a medium speed in order to reduce the oil loss. In

addition, as the differential pressure in the refrigerant circuit increases, the amount of oil loss addition, as the differential pressure in the refrigerant circuit increases, the amount of oil loss

increases, and increases, thus, in and thus, in general, general, the the oil oil return return operation is performed operation is witha alowlow performed with load load (low (low

differential pressure). differential pressure).

[0077]

If the oil level gauge detects that the oil level of the compressor (10) lowers, the oil If the oil level gauge detects that the oil level of the compressor (10) lowers, the oil

return operation is performed at a medium speed with a low load in order to secure the oil level. return operation is performed at a medium speed with a low load in order to secure the oil level.

Accordingly, the oil level rises. In contrast, an operation at a high speed with a high differential Accordingly, the oil level rises. In contrast, an operation at a high speed with a high differential

pressure causes increase in the amount of oil loss, and thus an operation at a high speed with a pressure causes increase in the amount of oil loss, and thus an operation at a high speed with a

high differential pressure is performed in order to decrease the oil level. high differential pressure is performed in order to decrease the oil level.

[0078]

22

In the first variation, an operation is performed as described above to control the oil In the first variation, an operation is performed as described above to control the oil

level of level of the the compressor (10) SO compressor (10) so that that the the resonance frequencyf1f1 of resonance frequency of the the first first resonance resonance mode is mode is

lower than lower than the the resonance resonancefrequency frequency f2 fof 2 of thesecond the second resonance resonance modemode at times. at all all times. Thus, Thus, the the

resonancefrequencies resonance frequenciesf1f1 and andf2f2 ofof the the two tworesonance resonancemodes modes do not do not match match each each other other at anyat any

point, and point, and thus thus noise noise increase increasecaused caused by by the the resonance resonance frequencies frequencies of of the thetwo two resonance resonance modes modes

overlappingeach overlapping eachother other can canbe bereduced. reduced.

[0079]

Similarly Similarly totothe thesecond second embodiment embodiment and the and firstthe first variation variation thereof, thereof, an an air conditioner air conditioner

of aa second of variation includes second variation includes aa refrigerant refrigerant circuit circuit (1) (1) including including aa compressor havinga afirst compressor having first

resonancemode resonance modeandand a second a second resonance resonance mode. mode.

[0080]

Unlike the first variation, the air conditioner operates to control the oil level of a Unlike the first variation, the air conditioner operates to control the oil level of a

compressor(10) compressor (10)SOsothat that the the resonance frequencyofofthe resonance frequency thefirst first resonance resonance mode is higher mode is higher than than the the

resonancefrequency resonance frequencyofofthe the second secondresonance resonancemode mode at at allalltimes timesduring duringa asteady steadyoperation operationinin the the

entire operation range. entire operation range.

[0081]

Also in the second variation, the resonance frequencies f and f of the two resonance Also in the second variation, the resonance frequencies f1 and f21 of the 2two resonance

modesdodonotnotmatch modes match each each other other at any at any point, point, and and thus thus similarly similarly to the to the first first variation, variation, noise noise

other can other can be be reduced. reduced.

[0082]

Similarly Similarly totothe thesecond second embodiment embodiment and the and the first first and andvariations second second variations thereof, anthereof, air an air

conditioner of a third variation includes a refrigerant circuit (1) including a compressor having conditioner of a third variation includes a refrigerant circuit (1) including a compressor having

23 a first a firstresonance resonancemode and aa second mode and secondresonance resonancemode. mode.

[0083]

The air conditioner operates to control the rotational speed of the compressor (10) to The air conditioner operates to control the rotational speed of the compressor (10) to

avoid aa point avoid point at at which the resonance which the frequenciesf1f1 and resonance frequencies and f2 f2 of of the the first firstresonance resonancemode and the mode and the

secondresonance second resonancemode mode match match eacheach other, other, thereby thereby controlling controlling the the resonance resonance frequency frequency of of the the

first first resonance mode. resonance mode. In other In other words, words, theconditioner the air air conditioner operates operates tothe to adjust adjust the rotational rotational speed speed

of the compressor (10) in order to adjust the oil level so that the resonance frequency f1 of the of the compressor (10) in order to adjust the oil level SO that the resonance frequency f1 of the

first firstresonance resonance mode donot mode do notmatch matchthe theresonance resonance frequency frequency f2 fof 2 of thesecond the second resonance resonance mode. mode.

Theoperation The operation of of adjusting adjusting the the oil oillevel in in level thethe second embodiment second embodiment can can be beperformed performed by by avoiding avoiding

an operation an operation of of the the compressor (10)and compressor (10) andnot notperforming performinga asteady steadyoperation operationatata apoint pointatat which which

the resonance the frequenciesofofthe resonance frequencies the first first resonance modeand resonance mode andthethesecond second resonance resonance mode mode matchmatch

each other. each other.

[0084]

Also in Also in the the third third variation, variation,the theresonance resonance frequencies f1 and frequencies f1 and ff2 2 of of the the two two resonance resonance

modes do not match each other at any point, and thus similarly to the first and second variations, modes do not match each other at any point, and thus similarly to the first and second variations,

each other each other can can be be reduced. reduced.

[0085]

<<Other Embodiments>> <<Other Embodiments>

Theabove The aboveembodiments embodimentsmay may be modified be modified as follows. as follows.

[0086]

For example, For example,the theabove aboveembodiments embodiments assume assume that compressor that the the compressor (10) (10) is is downsized downsized

and rotated at a high speed, but the configuration of the present disclosure is useful in reducing and rotated at a high speed, but the configuration of the present disclosure is useful in reducing

the noise the noise not not only only when when aa compressor compressorisis downsized downsizedandand rotatedatataahigh rotated highspeed speedbut butalso also when whena a

compressor in a typical size is rotated at a normal speed, when a compressor in a normal size is compressor in a typical size is rotated at a normal speed, when a compressor in a normal size is

24 24 compressor in a typical size is rotated at a normal speed, when a compressor in a normal size is 29 Oct 2024 2023242477 29 Oct 2024 rotated at a high speed, and when a compressor in a still smaller size is rotated at a normal speed.

The numerical values in the embodiments are not limited to themselves.

[0087]

55 While the embodiments and variations thereof have been described above, it will be 2023242477

understood that various changes in form and details may be made without departing from the

spirit and scope of the claims. The elements according to the embodiments, the variations

thereof, and the other embodiments may be combined and replaced with each other.

[0087a]

10 10 The term "comprise" and variants of that term such as "comprises" or "comprising" are

used herein to denote the inclusion of a stated integer or integers but not to exclude any other

integer or any other integers, unless in the context or usage an exclusive interpretation of the

term is required.

INDUSTRIAL APPLICABILITY

15 [0088]

As described above, the present disclosure is useful for a compressor and an air

conditioner. conditioner.

DESCRIPTION OF DESCRIPTION OF REFERENCE REFERENCECHARACTERS CHARACTERS

20 [0089]

1 Refrigerant Circuit

6 Oil Return Circuit

7 Oil Separator

10 Compressor

25 25 20 Casing

25

22 First First End Plate 29 Oct 2024 2023242477 29 Oct 2024

22 End Plate

23 23 Second EndPlate Second End Plate

30 30 Compression Mechanism

32b 32b Discharge Port (Fluid Outlet)

5 38 Muffler Muffler 5 38 2023242477

40 40 Electric Electric Motor Motor

60 60 Primary Space

26

Claims

CLAIMS 04 Dec 2025

[Claim 1] A compressor including:

a casing having a cylindrical shape and including end plates at both ends;

5 a compression mechanism housed in the casing; and 2023242477

a muffler disposed between a fluid outlet of the compression mechanism and a space

in the casing,

wherein

the compressor further comprises an electric motor disposed above the compression

10 mechanism and configured to drive the compression mechanism,

a resonance frequency of a first resonance mode is a resonance frequency of which

parameters are a volume of the muffler and a volume of a primary space formed between a

lower end of the electric motor and a bottom surface of the casing and changing in accordance

with an oil level,

15 a resonance frequency of a second resonance mode is a resonance frequency of which

a parameter is an inner diameter of part of the casing forming the primary space, and

a size of the casing or the muffler is set so that in an entire range of the first resonance

mode where the resonance frequency changes as the oil level of lubricant oil stored in the casing

changes, the resonance frequency of the first resonance mode is different from the resonance

20 frequency of the second resonance mode where the resonance frequency does not change as the

oil level of the lubricant oil changes.

[Claim 2] The compressor of claim 1, wherein

the resonance frequency of the first resonance mode is lower than the resonance

46979543 27 frequency of the second resonance mode at an oil level reached by an amount of oil initially 04 Dec 2025 supplied into the casing.

[Claim 3] The compressor of claim 1, wherein

5 the resonance frequency of the first resonance mode is higher than the resonance 2023242477

frequency of the second resonance mode with no lubricant oil being stored in the casing.

[Claim 4] The compressor of any one of claims 1 to 3, wherein

the compression mechanism is a single-cylinder compression mechanism.

10

[Claim 5] An air conditioner including a refrigerant circuit configured to

perform a vapor compression refrigeration cycle, wherein

the refrigerant circuit includes the compressor of any one of claims 1 to 4.

15 [Claim 6] An air conditioner including a refrigerant circuit configured to

perform a vapor compression refrigeration cycle, wherein

a compressor of the refrigerant circuit includes a casing having a cylindrical shape and

including end plates at both ends, a compression mechanism housed in the casing, and a muffler

disposed between a fluid outlet of the compression mechanism and a space in the casing; and

20 has a first resonance mode where a resonance frequency changes as an oil level of lubricant oil

stored in the casing changes and a second resonance mode where the resonance frequency does

not change as the oil level of lubricant oil stored in the casing changes,

the compressor further comprises an electric motor disposed above the compression

mechanism and configured to drive the compression mechanism,

25 a resonance frequency of a first resonance mode is a resonance frequency of which

46979543 28 parameters are a volume of the muffler and a volume of a primary space formed between a 04 Dec 2025 lower end of the electric motor and a bottom surface of the casing and changing in accordance with an oil level, a resonance frequency of a second resonance mode is a resonance frequency of which

5 a parameter is an inner diameter of part of the casing forming the primary space, and 2023242477

the resonance frequency of the first resonance mode is lower than the resonance

frequency of the second resonance mode at an oil level at which lubricant oil in the refrigerant

circuit is collected in the compressor.

10 [Claim 7] An air conditioner including a refrigerant circuit configured to

perform a vapor compression refrigeration cycle, wherein

a compressor of the refrigerant circuit includes a casing having a cylindrical shape and

including end plates at both ends, a compression mechanism housed in the casing, and a muffler

disposed between a fluid outlet of the compression mechanism and a space in the casing; and

15 has a first resonance mode where a resonance frequency changes as an oil level of lubricant oil

stored in the casing changes and a second resonance mode where the resonance frequency does

not change as the oil level of lubricant oil stored in the casing changes,

the compressor further comprises an electric motor disposed above the compression

mechanism and configured to drive the compression mechanism,

20 a resonance frequency of a first resonance mode is a resonance frequency of which

parameters are a volume of the muffler and a volume of a primary space formed between a

lower end of the electric motor and a bottom surface of the casing and changing in accordance

with an oil level,

a resonance frequency of a second resonance mode is a resonance frequency of which

46979543 29 a parameter is an inner diameter of part of the casing forming the primary space, and 04 Dec 2025 the air conditioner operates to control an oil level of the compressor so that the resonance frequency of the first resonance mode is lower than the resonance frequency of the second resonance mode at all times during a steady operation in an entire operation range.

5 2023242477

[Claim 8] An air conditioner including a refrigerant circuit configured to

perform a vapor compression refrigeration cycle, wherein

a compressor of the refrigerant circuit includes a casing having a cylindrical shape and

including end plates at both ends, a compression mechanism housed in the casing, and a muffler

10 disposed between a fluid outlet of the compression mechanism and a space in the casing; and

has a first resonance mode where a resonance frequency changes as an oil level of lubricant oil

stored in the casing changes and a second resonance mode where the resonance frequency does

not change as the oil level of lubricant oil stored in the casing changes,

the compressor further comprises an electric motor disposed above the compression

15 mechanism and configured to drive the compression mechanism,

a resonance frequency of a first resonance mode is a resonance frequency of which

parameters are a volume of the muffler and a volume of a primary space formed between a

lower end of the electric motor and a bottom surface of the casing and changing in accordance

with an oil level,

20 a resonance frequency of a second resonance mode is a resonance frequency of which

a parameter is an inner diameter of part of the casing forming the primary space, and

the air conditioner operates to control an oil level of the compressor so that the

resonance frequency of the first resonance mode is higher than the resonance frequency of the

second resonance mode at all times during a steady operation in an entire operation range.

25

46979543 30

[Claim 9] An air conditioner including a refrigerant circuit configured to 04 Dec 2025

perform a vapor compression refrigeration cycle, wherein

a compressor of the refrigerant circuit includes a casing having a cylindrical shape and

including end plates at both ends, a compression mechanism housed in the casing, and a muffler

5 disposed between a fluid outlet of the compression mechanism and a space in the casing; and 2023242477

has a first resonance mode where a resonance frequency changes as an oil level of lubricant oil

stored in the casing changes and a second resonance mode where the resonance frequency does

not change as the oil level of lubricant oil stored in the casing changes,

the compressor further comprises an electric motor disposed above the compression

10 mechanism and configured to drive the compression mechanism,

a resonance frequency of a first resonance mode is a resonance frequency of which

parameters are a volume of the muffler and a volume of a primary space formed between a

lower end of the electric motor and a bottom surface of the casing and changing in accordance

with an oil level,

15 a resonance frequency of a second resonance mode is a resonance frequency of which

a parameter is an inner diameter of part of the casing forming the primary space, and

the air conditioner avoids an operation of the compressor and does not perform a steady

operation at a point at which the resonance frequencies of the first resonance mode and the

second resonance mode match each other.

20

[Claim 10] The air conditioner of any one of claims 7 to 9, wherein

the air conditioner operates to control a rotational speed of the compressor to avoid a

point at which the resonance frequencies of the first resonance mode and the second resonance

mode match each other, thereby controlling the resonance frequency of the first resonance mode.

25

46979543 31

[Claim 11] The air conditioner of any one of claims 7 to 9, wherein 04 Dec 2025

the air conditioner operates to adjust an amount of oil returned to the compressor from

an oil return circuit including an oil separator connected to a discharge side of the compressor,

thereby controlling the oil level to control the resonance frequency of the first resonance mode.

5 2023242477

[Claim 12] The air conditioner of any one of claims 6 to 11, wherein

the compressor is a single-cylinder compressor.

[Claim 13] The air conditioner of claim 5 or 12, wherein

10 a rotational speed N (rps) of the compression mechanism is 120 ≤ N.

Daikin Industries, Ltd

Patent Attorneys for the Applicant/Nominated Person

SPRUSON & FERGUSON

15

46979543 32