Bearing Life Bearing Life Bearing life is defined

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Bearing Life

Bearing Life

Bearing Life Bearing life is defined as the Number of revolutions that a bearing

Bearing Life Bearing life is defined as the Number of revolutions that a bearing undergoes under a constant load ( Equivalent Dynamic Bearing Load ) before the first sign of fatigue failure occurs.

Bearing Life Fatigue - Spalling

Bearing Life Fatigue - Spalling

Bearing Life Equivalent Dynamic Bearing Load

Bearing Life Equivalent Dynamic Bearing Load

Bearing Life Equivalent Dynamic Bearing Load Fv FH

Bearing Life Equivalent Dynamic Bearing Load Fv FH

General Catalogue – Page 49 Bearing Life Equivalent Dynamic Bearing Load Values of Bearing

General Catalogue – Page 49 Bearing Life Equivalent Dynamic Bearing Load Values of Bearing Reaction Forces Can be calculated by using : S H = 0 ( Total of all horizontal forces = 0) S V = 0 ( Total of all vertical forces = 0) S M = 0 ( Total of all moments = 0)

General Catalogue – Page 49 Bearing Life Equivalent Dynamic Bearing Load P = X

General Catalogue – Page 49 Bearing Life Equivalent Dynamic Bearing Load P = X F r + Y Fa Where : X = Radial Load Factor Y = Axial Load Factor

Bearing Life Radial & Axial Load Factors DGBB : General Catalogue Pages 184 -

Bearing Life Radial & Axial Load Factors DGBB : General Catalogue Pages 184 - 185 P = Fr if Fa/Fr </= e P = X F r + Y Fa if Fa/Fr > C 0 is given in Pages 186 – 253 e is given in Page 185 e

Bearing Life Radial & Axial Load Factors SABB : General Catalogue Page 261 P

Bearing Life Radial & Axial Load Factors SABB : General Catalogue Page 261 P = F r + Y 1 Fa if Fa/Fr </= e P = 0. 65 Fr + Y 2 Fa if Fa/Fr > Y 1, Y 2 & e are given in Pages 264 – 283 e

Bearing Life Radial & Axial Load Factors ACBB : General Catalogue Page 292 Single

Bearing Life Radial & Axial Load Factors ACBB : General Catalogue Page 292 Single Bearing / Tandem : P = Fr if Fa/Fr </= 1. 14 P = 0. 35 Fr + 0. 57 Fa if Fa/Fr > 1. 14 Paired X or O : P = Fr + 0. 55 Fa P = 0. 57 Fr + 0. 93 Fa if if Fa/Fr </= 1. 14 Fa/Fr > 1. 14

Bearing Life Radial & Axial Load Factors DRACBB : General Catalogue Page 311 P

Bearing Life Radial & Axial Load Factors DRACBB : General Catalogue Page 311 P = Fr + 0. 73 Fa P = 0. 62 Fr + 1. 17 Fa if if Fa/Fr </= 0. 86 Fa/Fr > 0. 86

Bearing Life Radial & Axial Load Factors CRB : General Catalogue Page 336 P

Bearing Life Radial & Axial Load Factors CRB : General Catalogue Page 336 P = Fr For Flanged CRB, P = Fr P = 0. 92 Fr + Y Fa if Fa/Fr </= e if Fa/Fr > e Y & e are given in Page 336

Bearing Life Radial & Axial Load Factors SRB : General Catalogue Page 467 P

Bearing Life Radial & Axial Load Factors SRB : General Catalogue Page 467 P = F r + Y 1 Fa if Fa/Fr </= e P = 0. 67 Fr + Y 2 Fa if Fa/Fr > Y 1, Y 2 & e are given in Pages 470 – 511 e

Bearing Life Radial & Axial Load Factors SRTRB : General Catalogue Page 520 -

Bearing Life Radial & Axial Load Factors SRTRB : General Catalogue Page 520 - 521 P = Fr P = 0. 4 Fr + Y Fa if Fa/Fr </= e if Fa/Fr > Y & e are given in Pages 526 – 585 e

Bearing Life Radial & Axial Load Factors Paired TRB : General Catalogue Page 589

Bearing Life Radial & Axial Load Factors Paired TRB : General Catalogue Page 589 P = F r + Y 1 Fa if Fa/Fr </= e P = 0. 67 Fr + Y 2 Fa if Fa/Fr > Y 1, Y 2 & e are given in Pages 590 – 593 e

Bearing Life Radial & Axial Load Factors Th. BB / CRTh. B : General

Bearing Life Radial & Axial Load Factors Th. BB / CRTh. B : General Catalogue Page 597/622 P = Fa

Bearing Life Radial & Axial Load Factors SRTh. B : General Catalogue Page 646

Bearing Life Radial & Axial Load Factors SRTh. B : General Catalogue Page 646 P = Fa + 1. 2 Fr if Fr </= 0. 55 Fa P = 0. 88(Fa + 1. 2 Fr ) if adjustable assembly & Fr </= 0. 55 Fa

Bearing Life Fluctuating Bearing Load Constant Mean Load Fm = 3 ( F 13

Bearing Life Fluctuating Bearing Load Constant Mean Load Fm = 3 ( F 13 U 1 + F 23 U 2 + F 33 U 3 + ……. ) U Where F 1, F 2 etc = Constant Loads during U 1, U 2 revolutions U = Total number of revolutions ( U = U 1 + U 2 + U 3……)

General Catalogue – Page 35 Bearing Life L 10 = C p P (

General Catalogue – Page 35 Bearing Life L 10 = C p P ( ) Lundberg Palmgren Equation 1947

General Catalogue – Page 35 Bearing Life C p P ( ) C p

General Catalogue – Page 35 Bearing Life C p P ( ) C p a a = (P) L 10 = Lna 1 23 Lundberg Palmgren Equation 1947 Adjusted Rating Life Equation 1977

General Catalogue – Page 40 Bearing Life C p P ( ) C p

General Catalogue – Page 40 Bearing Life C p P ( ) C p a a = (P) C p =aa (P) L 10 = Lna L naa Lundberg Palmgren Equation 1947 1 23 Adjusted Rating Life Equation 1977 1 SKF New SKF Life Equation 1989

Bearings are selected based on: Ø Load Ø Speed Ø Temperature Ø Environment Ø

Bearings are selected based on: Ø Load Ø Speed Ø Temperature Ø Environment Ø Life expectancy

General Catalogue – Page 27 Basic Terminologies : 1. Static Load 1. Dynamic Load

General Catalogue – Page 27 Basic Terminologies : 1. Static Load 1. Dynamic Load 1. Life Requirement

Bearing Life considerations vary depending on : Type of Rolling Element 1. 2. Ball

Bearing Life considerations vary depending on : Type of Rolling Element 1. 2. Ball Roller a. Cylindrical b. Needle c. Tapered d. Spherical I Symmetrical II Asymmetrical

Different Applications require different Life: 1. Hand Tool 2. Elevator 3. Machine Tools 4.

Different Applications require different Life: 1. Hand Tool 2. Elevator 3. Machine Tools 4. Industrial Fans 5. Pumps 6. Water Circulating Pumps

General Catalogue – Page 53 Load carrying capacity Basic dynamic load rating C P

General Catalogue – Page 53 Load carrying capacity Basic dynamic load rating C P Basic static load rating C P 0 P 0 The ISO life equation C p The static safety factor L 10 = basic rating life, millions of s 0 revolutions C = basic dynamic load rating, N P = equivalent dynamic bearing load, N p = exponent of the life equation With the load P = C the L 10 life will be 1 million revolutions P 0 = equivalent static bearing load, N L 10 = (P) s 0 = C 0 P 0 = static safety factor C 0 = basic static load rating, N With the load P = C 0 the static safety factor s 0 will be 1

General Catalogue – Page 52 Equivalent Static Bearing Load P 0 = X 0

General Catalogue – Page 52 Equivalent Static Bearing Load P 0 = X 0 Fr + Y 0 Fa Where : X 0 = Static Radial Load Factor Y 0 = Static Axial Load Factor

Equivalent Static Bearing Load Radial & Axial Load Factors DGBB : General Catalogue Pages

Equivalent Static Bearing Load Radial & Axial Load Factors DGBB : General Catalogue Pages 184 P 0 = 0. 6 Fr + 0. 5 Fa If P 0 < Fr, then P 0 = Fr

Equivalent Static Bearing Load Radial & Axial Load Factors SABB : General Catalogue Pages

Equivalent Static Bearing Load Radial & Axial Load Factors SABB : General Catalogue Pages 261 P 0 = F r + Y 0 Fa Y 0 given in bearing tables pages 264 - 283

Equivalent Static Bearing Load Radial & Axial Load Factors ACBB : General Catalogue Pages

Equivalent Static Bearing Load Radial & Axial Load Factors ACBB : General Catalogue Pages 292 P 0 = 0. 5 Fr + 0. 26 Fa If P 0 < Fr, then P 0 = Fr

Equivalent Static Bearing Load Radial & Axial Load Factors CRB : General Catalogue Pages

Equivalent Static Bearing Load Radial & Axial Load Factors CRB : General Catalogue Pages 336 P 0 = F r

Equivalent Static Bearing Load Radial & Axial Load Factors SRB : General Catalogue Pages

Equivalent Static Bearing Load Radial & Axial Load Factors SRB : General Catalogue Pages 467 P 0 = F r + Y 0 Fa Y 0 given in bearing tables pages 470 - 511

Equivalent Static Bearing Load Radial & Axial Load Factors SRTRB : General Catalogue Pages

Equivalent Static Bearing Load Radial & Axial Load Factors SRTRB : General Catalogue Pages 520 P 0 = 0. 5 Fr + Y 0 Fa If P 0 < Fr, then P 0 = Fr Y 0 given in bearing tables pages 526 - 585

Equivalent Static Bearing Load Radial & Axial Load Factors Th BB & Th RB

Equivalent Static Bearing Load Radial & Axial Load Factors Th BB & Th RB : General Catalogue Pages 597 , 622 & 637 P 0 = Fa

Equivalent Static Bearing Load Radial & Axial Load Factors SR Th B : General

Equivalent Static Bearing Load Radial & Axial Load Factors SR Th B : General Catalogue Page 646 P 0 = Fa + 2. 7 Fr If Fr < 0. 55 Fa

Bearing Life L 10 = C p P ( ) Lundberg Palmgren Equation 1947

Bearing Life L 10 = C p P ( ) Lundberg Palmgren Equation 1947 L 10 = Basic Rating Life, Millions of Revolutions C P p = Basic Dynamic Load Rating , N = Equivalent Dynamic Bearing Load, N = Exponent of the life equation = 3 for ball bearings = 10/3 for roller bearings

Bearing Life L = 10 h 1 000 60 n ( ) C P

Bearing Life L = 10 h 1 000 60 n ( ) C P p Lundberg Palmgren Equation 1947 L 10 h = Basic Rating Life, Operating Hours C P p n = Basic Dynamic Load Rating , N = Equivalent Dynamic Bearing Load, N = Exponent of the life equation = 3 for ball bearings = 10/3 for roller bearings = Rotational Speed rpm

General Catalogue – Page 34

General Catalogue – Page 34

General Catalogue – Page 33

General Catalogue – Page 33

Adjusted Rating Life Equation L = a 1 a 23 na C p P

Adjusted Rating Life Equation L = a 1 a 23 na C p P ( ) Lna = Adjusted Rating Life, Millions of Revolutions a 1 = Life Adjustment Factor for Reliability a 23 = Life Adjustment Factor for Material and Lubrication

General Catalogue – Page 35 Reliability Factor a 1

General Catalogue – Page 35 Reliability Factor a 1

General Catalogue – Page 39 Material & Lubrication Factor a 23

General Catalogue – Page 39 Material & Lubrication Factor a 23

New SKF Life Equation 1989 L = a 1 a SKF naa C p

New SKF Life Equation 1989 L = a 1 a SKF naa C p (P) Lnaa = Adjusted Rating Life to new life theory, Millions of Revolutions a 1 = Life Adjustment Factor for Reliability a. SKF = Life Adjustment Factor for Material, Lubrication, Minimum load and Contamination

General Catalogue – Page 41

General Catalogue – Page 41

General Catalogue – Page 42

General Catalogue – Page 42

General Catalogue – Page 43

General Catalogue – Page 43

General Catalogue – Page 44

General Catalogue – Page 44

Oscillating Bearing Life L 10 osc = 180 / 2 g * L 10

Oscillating Bearing Life L 10 osc = 180 / 2 g * L 10 Where L 10 osc = Basic rating life in Millions of revolutions g = Oscillation amplitude ( Angle of maximum deviation from centre position), degrees For determining the required viscosity of the lubricating oil, equivalent rotational speed is calculated using : n = ( 2 g / 180 ) nosc

General Catalogue : Page 65

General Catalogue : Page 65

P M (t h o us an ds ) Deep Grove Ball Bearing Speed

P M (t h o us an ds ) Deep Grove Ball Bearing Speed Ratings 6217 Series