[go: up one dir, main page]

WO2016065257A1 - Compresseur de fluide - Google Patents

Compresseur de fluide Download PDF

Info

Publication number
WO2016065257A1
WO2016065257A1 PCT/US2015/057110 US2015057110W WO2016065257A1 WO 2016065257 A1 WO2016065257 A1 WO 2016065257A1 US 2015057110 W US2015057110 W US 2015057110W WO 2016065257 A1 WO2016065257 A1 WO 2016065257A1
Authority
WO
WIPO (PCT)
Prior art keywords
rotor
race
electric motor
compression chamber
stator
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/US2015/057110
Other languages
English (en)
Inventor
Kevin Mumpower
Jeffry HAMILTON
Kelly Chandler
John TOLBERT, Jr.
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Bristol Compressors International LLC
Original Assignee
Bristol Compressors International LLC
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Bristol Compressors International LLC filed Critical Bristol Compressors International LLC
Priority to CN201580069612.9A priority Critical patent/CN107109941A/zh
Priority to KR1020177014125A priority patent/KR20170102213A/ko
Priority to EP15852600.4A priority patent/EP3209864A4/fr
Publication of WO2016065257A1 publication Critical patent/WO2016065257A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C23/00—Combinations of two or more pumps, each being of rotary-piston or oscillating-piston type, specially adapted for elastic fluids; Pumping installations specially adapted for elastic fluids; Multi-stage pumps specially adapted for elastic fluids
    • F04C23/02—Pumps characterised by combination with, or adaptation to, specific driving engines or motors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C18/00—Rotary-piston pumps specially adapted for elastic fluids
    • F04C18/02—Rotary-piston pumps specially adapted for elastic fluids of arcuate-engagement type, i.e. with circular translatory movement of co-operating members, each member having the same number of teeth or tooth-equivalents
    • F04C18/0207—Rotary-piston pumps specially adapted for elastic fluids of arcuate-engagement type, i.e. with circular translatory movement of co-operating members, each member having the same number of teeth or tooth-equivalents both members having co-operating elements in spiral form
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C27/00—Sealing arrangements in rotary-piston pumps specially adapted for elastic fluids
    • F04C27/008—Sealing arrangements in rotary-piston pumps specially adapted for elastic fluids for other than working fluid, i.e. the sealing arrangements are not between working chambers of the machine
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D25/00—Pumping installations or systems
    • F04D25/02—Units comprising pumps and their driving means
    • F04D25/06—Units comprising pumps and their driving means the pump being electrically driven
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B1/00—Compression machines, plants or systems with non-reversible cycle
    • F25B1/04—Compression machines, plants or systems with non-reversible cycle with compressor of rotary type
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K5/00—Casings; Enclosures; Supports
    • H02K5/04—Casings or enclosures characterised by the shape, form or construction thereof
    • H02K5/12—Casings or enclosures characterised by the shape, form or construction thereof specially adapted for operating in liquid or gas
    • H02K5/124—Sealing of shafts
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C18/00—Rotary-piston pumps specially adapted for elastic fluids
    • F04C18/30—Rotary-piston pumps specially adapted for elastic fluids having the characteristics covered by two or more of groups F04C18/02, F04C18/08, F04C18/22, F04C18/24, F04C18/48, or having the characteristics covered by one of these groups together with some other type of movement between co-operating members
    • F04C18/34—Rotary-piston pumps specially adapted for elastic fluids having the characteristics covered by two or more of groups F04C18/02, F04C18/08, F04C18/22, F04C18/24, F04C18/48, or having the characteristics covered by one of these groups together with some other type of movement between co-operating members having the movement defined in group F04C18/08 or F04C18/22 and relative reciprocation between the co-operating members
    • F04C18/344—Rotary-piston pumps specially adapted for elastic fluids having the characteristics covered by two or more of groups F04C18/02, F04C18/08, F04C18/22, F04C18/24, F04C18/48, or having the characteristics covered by one of these groups together with some other type of movement between co-operating members having the movement defined in group F04C18/08 or F04C18/22 and relative reciprocation between the co-operating members with vanes reciprocating with respect to the inner member

Definitions

  • the present subject matter relates generally to a fluid compressor.
  • a fluid compressor in which the fluid being compressed is compressed in a compression chamber within the motor driving the compressor.
  • Present fluid compressors generally include a compression chamber for compressing the fluid, and a separate electric motor to drive the apparatus that compresses the fluid in the compression chamber. Including these two separate mechanisms causes the overall structure to be bulky and costly. Accordingly, the present inventors sought out a way to include the compression apparatus inside the electric motor that drives the compression apparatus.
  • One aspect of the present invention broadly comprises a compressor including an electric motor including a rotor and a stator; and a compression device including a compression chamber and a compression mechanism.
  • the compression chamber is within either the rotor or the stator of the electric motor.
  • FIG. 1 illustrates a perspective view of one embodiment of the present invention
  • FIG. 2 is a side cutaway view of the embodiment shown in Figure 1;
  • FIG. 3 illustrates a perspective view of the embodiment shown in Figure 1 with the parts disassembled from each other;
  • FIG 4 illustrates a top view of the compression chamber at a start of the compression cycle
  • FIGS 5-7 illustrate a top view of the compression chamber at subsequent points of the compression cycle
  • FIG 8 illustrates a top view of the compression chamber at an end of the compression cycle
  • FIG 9 illustrates a perspective view of the rotor showing the cooling fluid fan and a cooling fluid inlet hole
  • FIG 10 illustrates an aspect of the present invention embodied as an axial compressor
  • FIG 1 1 illustrates an aspect of the present invention embodied as a scroll compressor
  • FIGS. 12A-12G illustrates a first embodiment of the seal of the present invention
  • FIG. 13A-13F illustrates the movement of the seal ring in the embodiment shown in FIGS. 12A-12G;
  • FIG. 14 shows a view of the bearings of one embodiment of the invention.
  • FIGS. 15 and 15 A illustrates a second embodiment of the seal of the present invention
  • FIGS. 16 and 16A illustrates an embodiment of a bearing of the present invention
  • FIGS. 17A-17E illustrates the second embodiment of the seal of the present invention
  • FIGS. 18A- 18G illustrates a third embodiment of the seal of the present invention.
  • FIG. 19 shows a top view of an embodiment of the invention with the compression chamber inside the stator.
  • Figures 1-9 depict a first embodiment of a rotary compressor.
  • the present invention can be applied to many other types of compressors including and not limited to: turbine compressors, scroll compressors, axial compressors, and screw compressors.
  • Figures 10 and 11 depict aspects the present invention embodied as an axial compressor and a scroll compressor, respectively.
  • compression mechanisms 200 are located within electric motors 250 of their respective compressors.
  • Each of these figures show a compressor including a compression mechanism inside either a rotor or a stator of the electric motor driving the compression mechanism, which is one aspect of the present invention.
  • rotary compressor 100 includes a housing 10 made of lower housing 12, main housing 14, and upper housing 16.
  • Lower housing 12 includes fluid intake 13 and upper housing 16 includes fluid exit 17.
  • the embodiment shown in Figures 1-9 includes three housing portions bolted together, but other configurations are possible as known in the art. The modifications are within the scope of the invention.
  • the housing contains a shaft 20 for a motor 30 including stator 32 and rotor 34.
  • Shaft 20 includes a lower hollow portion 22 that receives gas from intake 13 to be compressed.
  • Shaft 20 also includes an upper hollow portion 24 that receives compressed fluid to be communicated through valve 40 to fluid exit 17.
  • shaft 20 includes a slot 26 that receives a leaf spring 27 and a vane 28.
  • Electric motor 30 may be a single speed, multispeed, or variable speed motor. Further, electric motor 30 may be any type of electric motor including and not limited to an induction motor, a permanent magnet motor, a brushless DC motor, and a switched reluctance motor.
  • Compression chamber 36 has a cross-section of approximately a circle when viewed along the shaft direction, but a center of compression chamber 36 is offset from a center of shaft 20. Accordingly, compression chamber 36 rotates eccentrically around a center of shaft 20 during each compression cycle, as shown in Figures 4-8.
  • Figures 1 -9 show that the biasing of the vane 28 is done with leaf spring 27, this biasing may also be done by a coiled spring, or gas or fluid pressure, such as the gas or fluid within the compressor. These modifications are also within the scope of the invention.
  • vane 28 divides lower hollow portion 22 from upper hollow portion 24 such that fluid at first enters compression chamber 36, but cannot flow directly to fluid exit 17.
  • the vane causes the volume that the fluid can access to shrink, compressing the fluid, as shown in Figures 5-7.
  • upper hollow portion 24 becomes accessible to the fluid, as shown in Figure 8. The now compressed fluid can then travel out of the compression chamber 36 by passing through valve 40.
  • the outer wall of compression chamber 36 is a solid sleeve 36A (labeled in Figure 14) such as metal to prevent the fluid from escaping. This is in contrast to conventional electric motor rotors which may only contain laminate structures.
  • solid sleeve 36A may be made of steel.
  • the compressor may have a displacement of 10 in 3 .
  • the compressor may have a displacement of 0.5 to 200 in 3 .
  • higher displacements are more efficient.
  • the invention may be embodied using a screw compressor.
  • the compressor in Figures 1-9 may compress a refrigerant fluid such as an R-400 series or R-500 series refrigerant.
  • Other fluids may be compressed as well, and these modifications are all within the scope of the invention.
  • portions of the compressor components may extend beyond the length of the rotor and/or stator to allow greater displacements independent of the dimensions of the rotor and stator.
  • Figure 10 shows an axial compressor in which compression mechanism 200 extends in the length direction beyond the end of electric motor 250 at both ends.
  • the rotor also includes a cooling fluid fan 50 for driving cooling fluid through the rotor 34 to cool the portions within.
  • cooling fluid fan 50 includes vanes 52, one of which has a hole 54 at a base thereof. Each vane is at an acute angle with respect to the top of rotor 34, such that a vane with a hole 54 at its base can catch and drive cooling fluid outside the rotor 34 into the hole 54.
  • Rotor 34 may have passages therein in communication with hole 54 to allow the cooling fluid to penetrate and cool the internal rotor parts. The cooling fluid can then exit the rotor through hole 56 (labeled in Figure 14) on a lower surface of rotor 34.
  • the cooling fluid may be oil, refrigerant, or lubricating fluid, or a combination of these fluids.
  • Figure 9 shows a rotor 34 with a single hole 54 at the base of one of six vanes 52.
  • multiple vanes 52 may have holes at their base, such as each of 6 vanes having a hole at their base.
  • the angle between the top of rotor 34 and each oil vane may be between 0 and 90 degrees. All of these modifications are within the scope of the invention.
  • FIGs 12A-12G shows close-ups of the first embodiment of seal 80 shown in Figure 1.
  • Seal 80 includes upper race 82, lower race 84, seal ring 86, and o-rings 88 and 89.
  • Upper race 82 includes an annular groove 82A around an outer perimeter and an annular groove 82B around an inner perimeter.
  • Lower race 84 includes an annular groove 84A around an inner perimeter and an annular groove 84B around an inner perimeter.
  • O-ring 88 is located in groove 82B to frictionally seal the upper race 82 to the shaft such that upper race 82 rotates with the rotor.
  • O- ring 89 is located in groove 84B to seal the interface between the lower race 84 and the upper bearing cup 92 (labeled in Figure 14).
  • Seal ring 86 is initially located in groove 82 A of the upper race when the motor is off. However, as the motor runs, split 86A in seal ring 86 allows seal ring 86 to increase in diameter as the rotor spins, which then causes the seal ring to at least partially enter groove 84A of the lower race 84, as shown in Figures 13A-13F. This allows the seal ring to prevent any contaminants from passing through the interface between the upper and lower races.
  • Figure 14 shows a close-up of the bearings 90A and 90B.
  • bearings 90 A and 90B are bronze, oil lubricated, sleeve drawn bushings.
  • other bearings are possible, such as magnetic, oil-less, and sealed roller bearings. All of these modifications are within the scope of the invention.
  • Upper bearing 90A supports the upper end of rotor 34
  • lower bearing 90B supports the lower end of rotor 34.
  • Bearings 90A and 90B are located much closer together than conventional bearings.
  • each of bearings 90A and 90B extend within the opening at each end of rotor 34 into the central passage of the rotor 34 where shaft 20 is located. This allows for a more stable running condition and less load on the bearings. Further, they have a larger diameter and are longer in length than conventional bearings, which provides more support than conventional bearings.
  • the upper bearing 90A is adjacent the upper bearing cup 92, which may be made of steel.
  • the lower bearing 90B is adjacent the lower bearing cup 94, which also may be made of steel.
  • rotor 34 may include aluminum rotor end rings 34A which are roughly even in height with the bearings 90A and 90B, while the portion of rotor 34 between the bearings 90A and 90B may be steel laminations 34B. As noted previously, rotor 34 also include steel sleeve 36A which provides the outer boundary of compression chamber 36.
  • Figures 15 and 15A show a second embodiment of a seal of the present invention.
  • Seal 180 includes an outer race 184 and an inner race 182, shown in Figure 17A.
  • Inner race 182 includes surface 182A that contacts surface 184 A of outer race 184. This provides a seal to prevent oil from leaking out of the compressor.
  • the angle of surface 182A and 184A may be, for example, 20° with respect to the vertical. However, other configurations are within the scope of the invention as claimed.
  • o-rings are located in grooves in the inner surface of the inner race and the outer surface of the outer race.
  • Figures 16 and 16A show an embodiment of a sealed bearing of the present invention.
  • Bearing 280 includes metal spheres 282 located between inner race 286 and outer race 284.
  • FIGS 18A-18G illustrate a third embodiment of the seal of the present invention.
  • Seal 380 includes inner race 382, outer race 384, and seal ring 388.
  • Outer race 384 includes surface 384A which contacts seal ring 388
  • inner race 382 includes surface 382A which also contacts seal ring 388. Accordingly, seal ring 388 can prevent oil from leaking out through the interface between the inner and outer races.
  • surfaces 382A and 384A make an angle of 45° with respect to the vertical.
  • other configurations are within the scope of the invention as claimed.
  • FIG 19 illustrates an embodiment of the invention where the compression chamber is inside the stator instead of the rotor, as shown in Figures 1-9.
  • Compressor 500 includes compression chamber 536 inside stator 532, which is inside rotor 534. Vane 528 moves in and out of shaft 520 to expand and contract the side of compression chamber 536.
  • a compressor with the compression chamber inside the stator can operate in a similar manner as the compressor shown in Figures 1 -9.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Power Engineering (AREA)
  • Applications Or Details Of Rotary Compressors (AREA)
  • Compressor (AREA)

Abstract

L'invention concerne un appareil comprenant un moteur électrique comportant un rotor et un stator, et un dispositif de compression comportant une chambre de compression et un mécanisme de compression. La chambre de compression est située à l'intérieur du rotor ou du stator du moteur électrique.
PCT/US2015/057110 2014-10-24 2015-10-23 Compresseur de fluide Ceased WO2016065257A1 (fr)

Priority Applications (3)

Application Number Priority Date Filing Date Title
CN201580069612.9A CN107109941A (zh) 2014-10-24 2015-10-23 流体压缩机
KR1020177014125A KR20170102213A (ko) 2014-10-24 2015-10-23 유체컴프레서
EP15852600.4A EP3209864A4 (fr) 2014-10-24 2015-10-23 Compresseur de fluide

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US201462068375P 2014-10-24 2014-10-24
US62/068,375 2014-10-24
US14/921,302 US20160146207A1 (en) 2014-10-24 2015-10-23 Fluid compressor
US14/921,302 2015-10-23

Publications (1)

Publication Number Publication Date
WO2016065257A1 true WO2016065257A1 (fr) 2016-04-28

Family

ID=55761626

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2015/057110 Ceased WO2016065257A1 (fr) 2014-10-24 2015-10-23 Compresseur de fluide

Country Status (3)

Country Link
US (1) US20160146207A1 (fr)
KR (1) KR20170102213A (fr)
WO (1) WO2016065257A1 (fr)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3078858A1 (fr) * 2015-04-07 2016-10-12 WABCO Europe BVBA Compresseur à vide électrique lubrifié à l'huile, compact et hautement intégré

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20050201884A1 (en) * 2004-03-09 2005-09-15 Dreiman Nelik I. Compact rotary compressor with carbon dioxide as working fluid
US20060159570A1 (en) * 2005-01-18 2006-07-20 Manole Dan M Rotary compressor having a discharge valve
US7521827B2 (en) * 2005-06-25 2009-04-21 Isotech Of Illinois, Inc. Motor ground seal
WO2010010998A2 (fr) * 2008-07-22 2010-01-28 Lg Electronics, Inc. Compresseur
US20140183998A1 (en) * 2005-06-25 2014-07-03 Inpro/Seal Llc Current Diverter Ring

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2420124A (en) * 1944-11-27 1947-05-06 Coulson Charles Chilton Motor-compressor unit
US2898032A (en) * 1955-09-29 1959-08-04 Bbc Brown Boveri & Cie Sealed motor-compressor unit
US5221095A (en) * 1989-06-14 1993-06-22 Inpro Companies, Inc. Static and dynamic shaft seal assembly
KR101767063B1 (ko) * 2010-12-29 2017-08-10 엘지전자 주식회사 밀폐형 압축기

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20050201884A1 (en) * 2004-03-09 2005-09-15 Dreiman Nelik I. Compact rotary compressor with carbon dioxide as working fluid
US20060159570A1 (en) * 2005-01-18 2006-07-20 Manole Dan M Rotary compressor having a discharge valve
US7521827B2 (en) * 2005-06-25 2009-04-21 Isotech Of Illinois, Inc. Motor ground seal
US20140183998A1 (en) * 2005-06-25 2014-07-03 Inpro/Seal Llc Current Diverter Ring
WO2010010998A2 (fr) * 2008-07-22 2010-01-28 Lg Electronics, Inc. Compresseur

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
"Inpro/Seal Bearing Isolator", UPLOADED BY SARATOGACOM, 15 November 2010 (2010-11-15), XP054977948, Retrieved from the Internet <URL:https://youtu.be/Lr7hlo890eA> [retrieved on 20151216] *

Also Published As

Publication number Publication date
KR20170102213A (ko) 2017-09-08
US20160146207A1 (en) 2016-05-26

Similar Documents

Publication Publication Date Title
US20180066657A1 (en) Compressor
US20050031465A1 (en) Compact rotary compressor
US20160032925A1 (en) Revolving piston rotary compressor with stationary crankshaft
CN106032794B (zh) 一体化高转速斜盘旋转式电机泵
JP2014231752A (ja) ロータリコンプレッサ及び冷凍サイクル装置
US20070231171A1 (en) Displacement type compressor
EP2376782B1 (fr) Compresseur alternatif et appareil de réfrigération comprenant celui-ci
KR102207772B1 (ko) 원통 대칭형 용적 기계
JP2019178675A (ja) 電動圧縮機
CN107208638A (zh) 具有油泵组件的压缩机
CA2768255C (fr) Support de pales dans une pompe quasi-turbine
US20160146207A1 (en) Fluid compressor
EP3209864A1 (fr) Compresseur de fluide
CN109538301B (zh) 圆柱形对称容积式机器
JPH0286976A (ja) スクロール流体機械
JP2018076780A (ja) 冷媒圧縮機
CN115038868A (zh) 具有轴流马达的往复式封闭压缩机
CN211924400U (zh) 往复式压缩机
JPWO2017187534A1 (ja) 固定子、モータ、圧縮機および冷凍サイクル装置
KR20210010808A (ko) 스크롤 압축기
WO2015107840A1 (fr) Compresseur à suralimentation électrique
JP5764715B2 (ja) スクロール圧縮機
CN211950783U (zh) 往复式压缩机
CN211924399U (zh) 往复式压缩机
KR20110015850A (ko) 압축기

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 15852600

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

REEP Request for entry into the european phase

Ref document number: 2015852600

Country of ref document: EP

ENP Entry into the national phase

Ref document number: 20177014125

Country of ref document: KR

Kind code of ref document: A