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1 산업용기어및오일적용 Customer Date: 2007 년 9월 13 일 By 한국쉘석유

2 Gear Oils Presentation 기어의종류 (Type of gears) 기어제작사 (Gear Manufacturers ) OEM Approvals 기어윤활 (Gear Lubrication) 합성기어오일 성능과이점 Synthetic gear oils performances and benefits 열발생이적음 (Lower heat generation) 에너지절약 (Energy conservation )

3 Types of gears -most common spur helical worm

4 Types of gears less common spiral bevel bevel offse t Hyp oid g e a rs internal skew

5 밀폐기어 (Enclosed gears) Spur, helical (and related) types 주로강재질사용대체로병행된입력, 출력샤프트의감속을위해사용치면접촉은롤링과슬라딩이동시에일어난다작은에너지낭비율 (2%)

6 기어치면의구조및명칭 * Pitch line velocity (m/s)=pitch line 높이의 Pitch Circle 상의속도 P a r ts o f a G e a r Wh e e l

7 기어들사이의작용원리 Roll Slide Slide Driver Roll Slide Roll

기어치면에상대적으로부하가적고접촉면은크다 강과강재질보다낮은압력으로접촉이됨 contact

8 밀폐기어 (Enclosed gears) - 웜기어 (Worm gears) 강재질의웜과청동의웜휠 (worm wheel) 로구성 높은감속이목적, 대체로교차식입력, 출력샤프트로구성 기어치면에상대적으로부하가적고접촉면은크다 강과강재질보다낮은압력으로접촉이됨 contact pressures low compared with steel/steel 작동중슬라딩으로인해에너지낭비가크다 (5~25%)

9 Gear manufacturers

10 기어오일의규격들 ( Specifications) National Standards (ASTM, DIN, IP,... ) International Standards (ISO) Industry Standards (AGMA, US Steel, etc ) Industry Specifications (Flender, Hansen, SEW, David Brown.. ) Shell (Brand standards) 10

11 A Smooth Surface?

12 기어윤활 고속으로작동하고매우하중이작게걸리는기어는유체역학적또는두꺼운유막윤활조건으로효과적으로윤활되어진다 Very lightly loaded gears, operating at high speed, are effectively lubricated under the conditions of hydrodynamic or thick-film lubrication 저속으로작동되고고하중이걸리는기어들은경계 ( 극압 ) 윤활로윤활되어지며이유막은매우얇고기어치면상의금속대금속접촉이심하다 Heavily loaded gears, especially those operating at low speed, are lubricated under the conditions of boundary lubrication. The lubricant film is very thin and there is significant metal-to-metal contact between gear teeth. 유체탄성역학윤활 ( 상기혼합 mixed 두조건 ) 은가장많은기어에존재하는윤활조건이다 Elastohydrodynamic lubrication is the lubrication condition which exist in most gears. 12

13 기어윤활 Elastohydrodynamic ( 혼합윤활 - 유체탄성학적 ) film profile 유막상에서이론상의압력분배도 13

14 기어윤활 혼합윤활 -Elastohydrodynamic (EHD)lubrication 두기어치면사이의유막은독특한형상을갖는다 많은영역에걸쳐균일한유막두께를갖으나오일이빠져나가기전에압축이일어난다 The oil film has a uniform thickness over most of the area, but there is a constriction just before it escapes. 혼합윤활 (EHD) 의최소유막두께인 H min 수치는윤활조건이만족한지를나타냄으로써중요하다 14

15 운동속도 (the speed of the motion) 접촉면에서굴곡진면의관련반지름 the relative radius of curvature of the surfaces in contact 윤활제의점도와변동압력 the viscosity of the lubricant and its variation with pressure 하중 - the load 기어윤활 혼합윤활 -Elastohydrodynamic lubrication H min 수치는아래와조건에좌우된다 : 표면의탄성특성 surfaces the elastic properties of the 15

16 기어윤활 Interpretation ( 해석 )of H min [µm] > 1,25 0,75-1,25 0,50-1,75 0, 개방식의큰기어에서만족함 (Satisfactory for large and open gears) 큰개방기어적게적용 ( Marginal for large open gears ) 밀폐식산업용기어에좋음 ( Good for enclosed industrial gears) 산업용밀폐형유욕식기어나분무식기어에적용 ( Generally satisfactory for industrial enclosed splash- or spray-lubricated gears) 기어면조도가정교하지않아서불만족 (Not satisfactory, unless a very high quality surface finish is used) < 0,25 불만족 (Unsatisfactory) 16

17 기어윤활 기어윤활의중요한주매개변수 (parameter) 는 : 최소한의 EHD film thickness H min [µm] 유지 특정유막두께 :Specific film thickness Λ ( 다우센비 : Dowsen ratio) 17

18 기어윤활 Specific film thickness( 특정유막두께 ): Λ = H min / (σ 1 ² + σ 2 ²) σ 1 and σ 2 는피니언 ( 구동 ) 휠과기어휠의표면조도 (R a in µm ) 를나타낸다 18

19 SFT는금속과금속접촉의확대를결정한다 기어윤활 Specific film thickness(sft): determines the extend of metal-to-metal contact Λ > 1.5 일때윤활조건은완전유체탄성학적윤활이다 When Λ > 1.5, the lubrication conditions are fully elastohydrodynamic Λ < 1.0 일때윤활조건은경제 ( 극압 ) 윤활이다 When Λ < 1.0, boundary lubrication conditions exist 마모의피로는 SFT(Λ) 와관련되어있다 The probability of wear distress is also related to the specific film thickness Λ. 19

20 기어윤활 hydrodynamic Lubrication mixed Lubrication boundary Lubrication Lubrication Condition Pitting, Micropitting Wear Scuffing Type of Gear failure 20

21 기어윤활 기어파손형태의분류 Classification of Gear Failure Gear Failure Surface Damage 표면손상 Tooth Fracture 치면파손 Pitting Wear Scuffing Plas tic Yielding Impact Fracture Abras ive Wear Overload Wear Corrosive Wear Fatigue Fracture Others 21

22 기어파손형태 기어윤활 Impact Fracture Abrasive Wear Fatigue Fracture Scuffing or Scoring Plastic Yielding 22

23 기어파손 : Micro-pitting 현상이란? 외관 1. 표면에미세한구멍 (<100 μm이하 ),Grey staining, frosting 현상 2. 연삭한결을따라생긴다 3. 치면 Dedemda ( 밑부분 ) 면에서생긴다 징후 1. 소리가난다 2. 급속한마모, 형상의 loss, 궁극적으로치면파손 3. 동력전달 loss 원인 1. 기어디자인, Tip relief ( 돋 ) 2. 슬라이딩각도 3. 기어치면조도 - 기어마무리공정에좌우 4. 재질경도, Case carburized 의성질 5. Loading downsizing 6. 표면처리, 표면코팅 7. 부적절한윤활제 23

24 1. Scuffing or Scoring Methods for preventing scuffing 기어윤활 ( 파손대처방법 1) Þ using smooth tooth surfaces, produced by careful grinding or honing; Þ reducing the load; Þ running at high speeds, if possible; and Þ ensuring that the gear teeth are cooled adequately by the lubricant Plastic Yielding Methods for preventing plastic yielding; Þ reducing loads and eliminating shock loads; Þ using gears with greater surface hardness. 3. Abrasive Wear Methods for preventing abrasive wear Abrasive wear can be reduced in the following ways: Þ Debris from within the gearbox can be minimised by using surface-hardened gear teeth with smooth surfaces, together with high viscosity lubricants; Þ Contamination from the surroundings can be minimised by maintaining oil-tight seals and using filtered breather vents located in clean areas; Þ Good housekeeping procedures should be followed to minimise the risk of introducing contamination during maintenance procedures; Þ The oil in systems which are splash lubricated should be changed regularly; Þ Gearboxes which are lubricated with circulating oil systems should be equipped with efficient oil 24 filters.

25 기어파손의원인 Heat & Lubrcation 50% Metallurgy 10% Bending stress 10% Wear 15% Contact fatigue 15% 25

26 기어윤활 유막두께는점도가늘어날수록두꺼워진다 Film thickness increases as viscosity increases 유막두께는속도가증가되면서증가된다 Film thickness increases as speed increases 유막두께는온도가증가될수록줄어든다 Film thickness decreases as temperature increases 유막두께는하중이증가될수록줄어든다 Film thickness decreases as load increases 26

27 기어윤활 기어윤활유의중요한특성은점도이다 기어유의점도는모든운전조건아래서기어치면사이의적절한윤활막을유지하게충분히높아야한다 27

28 기어윤활 고속으로운전되는기어들은낮은점도를요구한다 저속으로작동하는기어들은고점도오일을필요로한다 고온에작동하는기어들은고점도오일을요구한다 저온에서작동되는기어는낮은점도오일을요구한다 28

29 기어윤활 고점도오일들은아래이유들로항상가장바람직하지않다 High viscosity oils are not always the most desirable because: 이것은부착성이늘어나동력손실을유발한다 they increase drag and give rise to increased power loss 이것은효과적인냉매역할을덜하게된다 they are less effective coolants 이것은과열되어오일이산화가빨리온다 they are more likely to overheat and become oxidised 이것은기포를더일으키게된다 they are more likely to foam 이것은오일의항유성을나빠지게한다 they have poor water separation (demulsibility) 이것은필터성을나쁘게한다 they are difficult to filter 이것은오염물을덜배출케한다 they shed contaminants less readily 29

30 기어윤활 산업용기어오일들은 ISO 에의해명기된시스템에따라점도별로나누어져있다 자동차용기어오일과엔진오일은 SAE 에서명기한시스템에의해분류되어있다 30

31 기어윤활 주윤활유의점도분류비교 DIN DIN DIN ISO-VG SAE, Gear Oils SAE, Engine Oils W 5 W W W W

32 기어윤활 오일교환간격은 (Oil change intervals:) Depending on: 기어박스디자인 윤활제의종류 운전형태 (type of service) 운전형태 주위의조건 정비조건 조건 ( 온도, 기후등 ) 32

33 (e.g. high speed > low viscosity) 기어윤활 기어오일추천시주요법칙 : All types of lubricant are Gear Lubricants 기어오일점도는기어주변의속도에따라선택되어져야한다 A/W & EP 함유수준은운전형태에따라선택되어져야한다 (e.g. shock loads > EP; low speed/high torque > A/W) 윤활제타입은운전온도나다른여건에따라선택되어져야한다 (e.g. high/low temperature; food compatible; etc.) 33

34 기어윤활 강 / 인- 청동계웜기어와강 / 니켈 - 청동계웜기어는 PAG 윤활제나광유계의 mild EP형오일이요구된다 Worm gears steel / P-bronze and steel / Ni-bronze require PAG lubricants or mild EP additivated mineral oils 강 / 알루미늄 - 청동계웜기어는광유계가요구되고 PAG 타입은알루미늄합금금속과는사용될수없다 Worm gears steel / Al-bronze require mineral oils. PAG s are not compatible with Al-alloys. 강 / 주철계웜기어는광유계을요구한다 Worm gears steel / cast iron require Omala-type mineral oils 강 / 강계웜기어는높은극압성이있는 High EP PAG나광유계 GL5 EP 급이요구된다 Worm gears steel /steel require high EP PAG s or mineral oils (GL 5 EP-level) 34

35 윤활제선택에영향을주는요소들 기어형태 (Gear type) Open or closed Helical, spur, bevel Worm Hypoid 속도 (Speed) 기어재질과기어표면조도 Gear materials and surface finish 운전온도 Operating temperature 하중특성 Load characteristics 윤활유선택은가능하면항상제조자추천에기본을두어야한다

36 점도선택차트 ( 일본자료 ) Viscosity selection simple method

37 점도선택차트 Viscosity selection simple method ISO viscosity grade (cst) Vk40 = 500 / sqrt (V) Dip Spray Pitch line velocity (m/s)

38 기어치면의구조및명칭 * Pitch line velocity (m/s)=pitch line 높이의 Pitch Circle 상의속도 Parts of a Gear Wheel

39 부하 ( 하중 ) 의영향 Influence of loading more complex Viscosity (cst) Load Dip Spray ISO viscosity grade Pitch line velocity (m/s)

40 합성기어오일 합성유는광유계와는매우다르다 합성유제들은매우유익한성능이있으나윤활성에서많은취약점도갖고있다 합성유제들은화학적으로매우다른특성을지닌매우다른기유들로구성된다 합성윤활제들은광유계오일보다좋은온도 - 점도특성 ( 유동점 / 점도지수 / 열안정성 ) 을갖고있어이런이유로많이사용되어진다 40

41 합성기어오일 주요이점 : 광유계와비교하여좋은점 대체적으로좋은저온온도특성을갖고있고 대체적으로좋은고온특성을지니고있으며 대체적으로높은 VI을갖으며 대체적으로마찰계수가낮으며 부분적으로는식품과도상용성이있다 부분적으로는생분해성을지니고있다 41

42 합성기어오일 기어오일용주요합성기유들 합성탄화수소계 - Poly-α-olefins (PAO) - Poly-iso-butylenes (PIB) 다가알콜계 Polyalkylene-glycols (PAG) 에스테르 -Esters 42

43 합성기어오일 Poly-α-olefins (PAO) / 2 PAOs는매우낮은유동점을갖고있다 PAOs 는 130이상 VI를갖고있다 PAOs 는식품과상용성이좋다 PAOs 는광유보다극성성향이적어첨가제용해성이감소한다 PAOs 고무밀봉재물질과수축하는 경향이있다 43

44 합성기어오일 Polyalkylene-glycols (PAG) / 1 PAGs 계는 ethylene oxides and propylene oxides 로이루어진다양한 CHAIN을갖는유제이다 PAGs 계는저온유동성이우수하며 VI가 200 이상되는고점도지수형유제이다 PAGs 계는기어윤활기유로최상의특성을가졌으나대량사용에는어려운단점이있다 PAGs 계는모든타입의기어에매우우수한윤활제이다 44

45 합성기어오일 Polyalkylene-glycols (PAG) / 2 적절히추가된 PAG계합성유제의산화안정도는광유계보다도 7 배가좋다 PAGs 계는과열되거나산화시퇴적물을남기지않는다. 이는산화물질들이가스화되거나액상으로기유내에완전히혼합되어진다 PAGs 계는매우낮은마찰계수를갖고있다 PAGs 계는 steel/bronze worm gears에최상의윤활제이다 PAGs 계는식품과상용성이좋다 45

46 합성기어오일의사용목적 Use of Synthetic Gear Oils 에너지절감 오일수명연장 기계부품수명연장 운전온도한계범위를확대 웜기어, 견인드라이브과같은특정한윤활제특성을요하는특정드라이브에적용시 일반광유계를요하지않는개소즉식품산업, 환경에민감개소, 위험한방사물질에노출되는개소에적용

47 에너지절감효과은많고다른 sources 로부터얻어질수있다 기어박스내에서 churning losses( 교반손실 ) 을감소 - 이는작동온도에서의윤활점도및지정량이상의 Top-up, 그리고기어박스디자인, 접촉효과등에의해주로영향을받습니다 순환계내에서유체마찰의감소 - 이는작동되는온도조건에서윤활제의점도및순환배관 (Pipe work) 디자인에의해영향을받습니다. 기어효율의증진 - 이는작동온도에서정지마찰효율이낮은합성윤활제사용으로증진시킬수있습니다

48 합성기어오일 160 기유타입에따른오일 Sump 온도비교표 140 [ 시험조건 ] Test rig: FZG gear Rig DIN Test gears: FFZG-A - DIN Test load: Load stage 10 (1538 N/mm²) Lubricant: Base oil + 2% A- xxx Over-Tem perature [K] 내저항성 LVI 68 HVI 68 PAO XHVI Circumfe re ncial Spe e d [m/s] 48

49 합성기어오일 220 Oil sump온도변화 [ 시험 Rig 조건 ] Test Rig: FZG Gear Rig DIN 51 Test GearsFZG-C/Pt Test Load: 1547,3 N/mm?at Pitch Test Durat 120 min per Test Cond Oil Sump Temperature [ ] Pitch Line Velocity [m/s] Omala 광유VG Oil Omala PAO Oil VG HD

50 웜기어박스 rig 시험 Worm gearbox rig arrangement Input shaft Test gearbox Electric motor Torque transducer Output shaft Torque transducer Hydraulic brake Torque meter Motor - gearbox - brake arrangement allows accelerated testing to be accomplished in a gearbox situation under conditions close to reality Torque and speed measurements enable gearbox efficiency to be determined 50

51 David Brown gearbox rig Electric motor Test gearbox

86 84 82 웜기어효율 (Worm gear efficiency) Tivela S gives 15% efficiency improvement over mineral oil and 11% over PAO Output and input torque data enable calculation of gearbox efficiency For a typical

52 웜기어효율 (Worm gear efficiency) Tivela S gives 15% efficiency improvement over mineral oil and 11% over PAO Output and input torque data enable calculation of gearbox efficiency For a typical factory running 50 gearboxes continuously, this equates to about and electricity savings/year efficiency, % 광유계 PAO Mild 형 PAO type 320 PAG type 320 A B 기존 PAG type 최근 PAG type

53 Bonfiglioli 사의 Oil Change Interval (hrs) 오일온도광유계합성계 (PAG) <65 8,000 25, ,000 15, ,000 12,500

54 호주마란두의 CV12에있는 2 개기어박스을이용한합성유실차시험 ( reported by Bruce Forster, Asset Management) 합성유가충진된기어박스가, 광유계기어유가충진된기어박스보다약4.5도낮은운전온도를나타내었다.

55 기어타입및운전조건에따른오일추천 Gear Operating Conditions Oil Type and Additives Typical Product Base Oil Spur 경하중 Straight mineral 광유계 고속고온 Turbine or hydraulic 광유계 /Hy/Turbin 고온 Low EP synthetic fluid PAO 정상 / 고하중 EP mineral oil 광유계 Micropitting 내저항성 EP mineral oil V. heavy load or + high temp EP synthetic fluid 광유계 for Micropit PAO with EP Helical 정상 / 고하중 EP mineral oil 광유계 Micropitting내저항성 EP mineral oil 광유계 for Micropit V. heavy load or + high temp EP synthetic fluid PAO witn EP Straight 중하중 / 충격하중 Full EP mineral oil or 광유계 bevel 부식내저항성 EP synthetic fluid PAO Spiral 비정상고하중 EP synthetic fluid PAO bevel (case-hardened gears) Hypoid 정상하중 Full EP mineral oil 광유계 for auto Gear 심한service EP synthetic fluid PAO for auto Gear Worm 정상하중 Straight mineral 광유계, 기계유 고온 Low EP synthetic fluid PAO With low EP 중하중 / 고온 Synthetic Polyglycol Crossed As worm gears As worm gears As Worm helical Gears All Food Handling PAO for Food 55

56 * 기어오일교환시작업요령 PAG 기어유로새기어박스에초도충진할시 500 시간을 running-in한후오일교환을추천한다. 따뜻한조건에서배출하고충진한다 광유계의사용유를교환시 따뜻한조건에서광유계를배출시키고무부하조건으로최소량의 new PAG 기어유로세척작업을하고따뜻한조건에서배출하고충진한다그리고 500 시간사용후재배출하고충진한다 급속한산화와슬러지문제를유발할수있는광유계오일과 PAG-based oils 과의오염은피하여야한다. 그리고밀봉재에대해검사를실시해야하고열화되어있으면교체해야한다. 이미광유에노출되어졌던밀봉재는다시 PAG-base 에노출되어지면수축이일어날수있기때문이다 다른합성유의사용유를교환시 (e.g. PAG- or PAO-based) 다른 PAG 타입조차도항상혼합하지않을수있다. 보충시주의가요망된다 혼합사용은되도록피하여야하고광유계의사용유를교환시절차를따라서교환한다 l

57 교환가능안내서 Changeover guidelines the various options MIN 1 MIN 2 PAO 1 PAO 2 PAG 1 PAG 2 MIN 1 MIN 2 PAO 1 PAO 2 PAG 1 PAG 2 Mixing and topping up with the same product allowed without restriction Products miscible, topping up allowed, pay attention to foam formation Products not always miscible, caution when topping up, advisable to drain Products not miscible/compatible, drain and flush required

58 기어오일의초기샘플에대한금속함량의경고레벨 Warning Level Guidelines for "Early Samples" Prior to Trend Lines Being Established Fe Cu Pb Sn Cr Al Si** Bo* Gear Oils (Manual, Automotive & Indus s > 10 > Worm Drives (Bronze Worm Wheels) Automatic & Powershift Transmissions Differentials / Final Drives * Boron may be as high as 1200 ppm if Borate Gear Oils are being used. Zinc will be as high as 600 ppm if Borate Gear Oils are being used. ** Silicon may be higher if Silicon-based anti-foam additive is used.

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À±È°Ãß°è½ÉÆ÷ÆÊÇÃ·¿ 59È¸-ÃÖÁ¾ http://www.kstle.or.kr 2014 The Korean Society of Tribologists & Lubrication Engineers 3 4 5~14 15~16 17 18 19 2 2014 10 www.kstle.or.kr 3 1. Overview of Industrial Lubricant and its Trend Dr. Kook-Wha