BS ISO 6336-1:2019
$215.11
Calculation of load capacity of spur and helical gears – Basic principles, introduction and general influence factors
| Published By | Publication Date | Number of Pages |
| BSI | 2019 | 146 |
This document presents the basic principles of, an introduction to, and the general influence factors for the calculation of the load capacity of spur and helical gears. Together with the other documents in the ISO 6336 series, it provides a method by which different gear designs can be compared. It is not intended to assure the performance of assembled drive gear systems. It is not intended for use by the general engineering public. Instead, it is intended for use by the experienced gear designer who is capable of selecting reasonable values for the factors in these formulae based on the knowledge of similar designs and the awareness of the effects of the items discussed.
The formulae in the ISO 6336 series are intended to establish a uniformly acceptable method for calculating the load capacity of cylindrical gears with straight or helical involute teeth.
The ISO 6336 series includes procedures based on testing and theoretical studies as referenced by each method. The methods are validated for:
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normal working pressure angle from 15° to 25°;
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reference helix angle up to 30°;
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transverse contact ratio from 1,0 to 2,5.
If this scope is exceeded, the calculated results will need to be confirmed by experience.
The formulae in the ISO 6336 series are not applicable when any of the following conditions exist:
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gears with transverse contact ratios less than 1,0;
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interference between tooth tips and root fillets;
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teeth are pointed;
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backlash is zero.
The rating formulae in the ISO 6336 series are not applicable to other types of gear tooth deterioration such as plastic deformation, case crushing and wear, and are not applicable under vibratory conditions where there can be an unpredictable profile breakdown. The ISO 6336 series does not apply to teeth finished by forging or sintering. It is not applicable to gears which have a poor contact pattern.
The influence factors presented in these methods form a method to predict the risk of damage that aligns with industry and experimental experience. It is possible that they are not entirely scientifically exact. Therefore, the calculation methods from one part of the ISO 6336 series is not applicable in another part of the ISO 6336 series unless specifically referenced.
The procedures in the ISO 6336 series provide rating formulae for the calculation of load capacity with regard to different failure modes such as pitting, tooth root breakage, tooth flank fracture, scuffing and micropitting. At pitch line velocities below 1 m/s the gear load capacity is often limited by abrasive wear (see other literature such as References [23] and [22] for further information on such calculation).
PDF Catalog
| PDF Pages | PDF Title |
|---|---|
| 2 | undefined |
| 8 | Foreword |
| 9 | Introduction |
| 11 | 1 Scope |
| 12 | 2 Normative references 3 Terms, definitions, symbols and abbreviated terms 3.1 Terms and definitions 3.2 Symbols and abbreviated terms |
| 21 | 4 Basic principles 4.1 Application 4.1.1 Surface durability (pitting) 4.1.2 Tooth bending strength |
| 22 | 4.1.3 Tooth flank fracture 4.1.4 Strength and quality of materials 4.1.5 Service life under variable load 4.1.6 Scuffing 4.1.7 Wear 4.1.8 Micropitting 4.1.9 Plastic-yielding 4.1.10 Specific applications |
| 23 | 4.1.11 Safety factors |
| 25 | 4.1.12 Testing 4.1.13 Manufacturing tolerances 4.1.14 Implied accuracy 4.1.15 Other considerations |
| 26 | 4.1.16 Influence factors |
| 28 | 4.1.17 Numerical formulae 4.1.18 Succession of factors in the course of calculation 4.1.19 Determination of allowable values of gear deviations 4.2 Tangential load, torque and power 4.2.1 General |
| 29 | 4.2.2 Nominal tangential load, nominal torque and nominal power 4.2.3 Equivalent tangential load, equivalent torque and equivalent power 4.2.4 Maximum tangential load, maximum torque and maximal power 5 Application factor, KA 5.1 General |
| 30 | 5.2 Method A — Factor KA-A 5.2.1 Factor KA-A 5.2.2 Factor KHA-A for pitting along ISO 6336-2 5.2.3 Factor KFA-A for tooth root breakage along ISO 6336-3 5.2.4 Factor KFFA-A for tooth flank fracture along ISO/TS 6336-4 |
| 31 | 5.2.5 Factor KϑA-A for scuffing along ISO/TS 6336-20/ISO/TS 6336-21 5.2.6 Factor KλA-A for micropitting along ISO/TS 6336-22 5.3 Method B — Factor KA-B 5.3.1 General 5.3.2 Guide values for application factor, KA-B |
| 34 | 6 Internal dynamic factor, Kv 6.1 General 6.2 Parameters affecting internal dynamic load and calculations 6.2.1 Design 6.2.2 Manufacturing |
| 35 | 6.2.3 Transmission perturbance 6.2.4 Dynamic response 6.2.5 Resonances |
| 36 | 6.2.6 Application of internal dynamic factor for low loaded gears 6.3 Principles and assumptions |
| 37 | 6.4 Methods for determination of dynamic factor 6.4.1 Method A — Factor Kv-A 6.4.2 Method B — Factor Kv-B 6.4.3 Method C — Factor Kv-C |
| 38 | 6.5 Determination of dynamic factor using Method B: Kv-B 6.5.1 General 6.5.2 Running speed ranges |
| 39 | 6.5.3 Determination of resonance running speed (main resonance) of a gear pair |
| 41 | 6.5.4 Dynamic factor in subcritical range (N ≤ NS) |
| 44 | 6.5.5 Dynamic factor in main resonance range (NS < N ≤ 1,15) 6.5.6 Dynamic factor in supercritical range (N ≥ 1,5) 6.5.7 Dynamic factor in intermediate range (1,15 < N < 1,5) |
| 45 | 6.5.8 Resonance speed determination for specific gear designs |
| 47 | 6.5.9 Calculation of reduced mass of gear pair with external teeth |
| 48 | 6.6 Determination of dynamic factor using Method C: Kv-C 6.6.1 General |
| 49 | 6.6.2 Graphical values of dynamic factor using Method C |
| 52 | 6.6.3 Determination by calculation of dynamic factor using Method C |
| 53 | 7 Face load factors, KHβ and KFβ 7.1 Gear tooth load distribution 7.2 General principles for determination of face load factors, KHβ and KFβ 7.2.1 General |
| 54 | 7.2.2 Face load factor for contact stress, KHβ 7.2.3 Face load factor for tooth root stress, KFβ 7.3 Methods for determination of face load factor — Principles, assumptions 7.3.1 General 7.3.2 Method A — Factors KHβ-A and KFβ-A |
| 55 | 7.3.3 Method B — Factors KHβ-B and KFβ-B 7.3.4 Method C — Factors KHβ-C and KFβ-C 7.4 Determination of face load factor using Method B: KHβ-B 7.4.1 Number of calculation points 7.4.2 Definition of KHβ 7.4.3 Stiffness and elastic deformations |
| 59 | 7.4.4 Static displacements 7.4.5 Assumptions 7.4.6 Computer program output 7.5 Determination of face load factor using Method C: KHβ-C 7.5.1 General |
| 61 | 7.5.2 Effective equivalent misalignment, Fβy 7.5.3 Running-in allowance, yβ, and running-in factor, χβ |
| 71 | 7.5.4 Mesh misalignment, fma |
| 73 | 7.5.5 Component of mesh misalignment caused by case deformation, fca 7.5.6 Component of mesh misalignment caused by shaft displacement, fbe |
| 74 | 7.6 Determination of face load factor for tooth root stress using Method B or C: KFβ |
| 75 | 8 Transverse load factors KHα and KFα 8.1 Transverse load distribution 8.2 Determination methods for transverse load factors — Principles and assumptions 8.2.1 General 8.2.2 Method A — Factors KHα-A and KFα-A |
| 76 | 8.2.3 Method B — Factors KHα-B and KFα-B 8.3 Determination of transverse load factors using Method B — KHα-B and KFα-B 8.3.1 General 8.3.2 Determination of transverse load factor by calculation |
| 77 | 8.3.3 Transverse load factors from graphs 8.3.4 Limiting conditions for KHα 8.3.5 Limiting conditions for KFα |
| 78 | 8.3.6 Running-in allowance, yα |
| 81 | 9 Tooth stiffness parameters, c′ and cγ 9.1 Stiffness influences 9.2 Determination methods for tooth stiffness parameters — Principles and assumptions 9.2.1 General |
| 82 | 9.2.2 Method A — Tooth stiffness parameters c′A and cγ-A 9.2.3 Method B — Tooth stiffness parameters c′B and cγ-B 9.3 Determination of tooth stiffness parameters, c′ and cγ, according to Method B 9.3.1 General |
| 83 | 9.3.2 Single stiffness, c′ |
| 87 | 9.3.3 Mesh stiffness, cγ 10 Parameter of Hertzian contact 10.1 Local radius of relative curvature |
| 88 | 10.2 Reduced modulus of elasticity, Er 10.3 Local Hertzian contact stress, pdyn,CP 10.3.1 Method A |
| 89 | 10.3.2 Method B |
| 90 | 10.4 Half of the Hertzian contact width, bH 10.5 Load distribution along the path of contact 10.5.1 Definition of contact points, CP, on the path of contact |
| 92 | 10.5.2 Load sharing factor, XCP |
| 100 | 10.6 Sum of tangential velocity, vΣ,CP |
| 101 | 11 Lubricant parameters at given temperature 11.1 General 11.2 Kinematic viscosity at a given temperature, vθ |
| 102 | 11.3 Density of the lubricant at a given temperature θ, ρθ |
| 103 | Annex A (normative) Additional methods for determination of fsh and fma |
| 106 | Annex B (informative) Guide values for crowning and end relief of teeth of cylindrical gears |
| 109 | Annex C (informative) Guide values for KHβ-C for crowned teeth of cylindrical gears |
| 112 | Annex D (informative) Derivations and explanatory notes |
| 116 | Annex E (informative) Analytical determination of load distribution |
| 138 | Annex F (informative) General symbols used for calculation of load capacity of spur and helical gears |
| 143 | Bibliography |
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