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GB/T 3480.3-2021Calculation of load capacity of spur and helical gears - Part 3: Calculation of tooth bending strength (English PDF)

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Issued by

State Administration for Market Regulation, China National Standardization Administration

Level / Type

National · Recommended

Issue date

April 30, 2021

Implementation date

November 1, 2021

Scope

GB/T 3480.3-2021 (Calculation of load capacity of spur and helical gears - Part 3: Calculation of tooth bending strength) is available as an English-translated PDF.

GB/T 3480.3-2021 is the Chinese standard "Calculation of load capacity of spur and helical gears - Part 3: Calculation of tooth bending strength".

Its scope clause reads: This part of GB/T 3480 specifies an involute with a certain rim thickness (external tooth SR >0.5ht and internal tooth SR >1.75mn) The basic formula for calculating the bending stress of cylindrical inner and outer spur gears and helical gears.

This section considers all the loads caused by the gears The factors that affect the root stress of the tooth can be quantitatively evaluated. In practice, internal gears may have a failure shape that is different from gear bending fatigue.

Formula, for example, the crack starts from the tooth root circle and expands radially outward. The calculation results in this section cannot ensure that the failure modes of non-bending fatigue are adequate.

Enough safety assessment. This part includes experimental tests and theoretical research conducted by Hirt [11], Strasser [14] and Brossmann [10]. Calculation The results are consistent with other methods (references [5], [6], [7] and [12]).

The formulas given in this section are applicable to comply with GB/T 1356 by The tooth profile of the cylindrical gear processed by the basic rack-type tool can also be used for the equivalent gear end surface coincidence epsilonalphan is less than 2.5 and can be combined with other basic racks.

Conjugate tooth profile. The bearing capacity derived from the allowable bending stress is called the "bending strength of gear teeth". This method of calculating the intensity is similar to other similar methods.

The method results are consistent, which has been explained in the "scope" in ISO 6336-1. If this section is not applicable, refer to Chapter 4 of ISO 6336-1.2019.

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Document preview — GB/T 3480.3-2021

National Standard of the People's Republic of China

Classification: J 17

Issued by: State Administration for Market Regulation, China National Standardization Administration

Preface
Introduction
1 Scope
2 Normative references
3 Terms, definitions, symbols and abbreviations
3.1 Terms and definitions
3.2 Symbols and abbreviations
4 Gear broken teeth and safety factor
5 Basic formula
5.1 Overview
5.2 Bending strength safety factor (to prevent gear teeth from breaking) SF
5.3 Calculated value of bending stress sigmaF
5.3.1 Overview
5.3.2 Method A
5.3.3 Method B
5.4 Permissible tooth root bending stress sigmaFP
5.4.1 Overview
5.4.3 Allowable tooth root bending stress sigmaFP. Method B
5.4.4 Permissible tooth root bending stress sigmaFP under limited life and high cycle fatigue life. Method B
6 Tooth profile factor YF
6.1 Overview
6.2 Calculation of tooth profile coefficient YF. Method B
6.2.1 Overview
6.2.2 Parameters of equivalent gear
7 Stress correction factor YS
7.1 Basic usage
7.2 Stress correction factor YS (Method B)
7.3 Stress correction factor for gears with stepped roots
7.4 Stress correction factor YST 20 related to the size of the test gear
8 Helix angle coefficient Ybeta
8.1 Overview
8.2 Graphical values
8.3 Analytical value
9 Flange thickness factor YB
9.1 Overview
9.2 Graphical values
9.3 Analytical value
9.3.1 External gear
9.3.2 Internal gear
10 Tooth height coefficient YDT
10.1 Overview
10.2 Graphical values
10.3 Analytical values
11 Bending durability limit
11.1 Overview
11.2 Endurance limit obtained by Method A
11.3 Endurance limit of relevant sigmaFlim and sigmaFE values obtained by method B
12 Flexural strength life factor YNT
12.1 Overview
12.2 Life factor YNT. Method A
12.3 Life factor YNT. Method B
12.3.1 Overview
12.3.2 Graphical values
12.3.3 Analytical values
13 Tooth root fillet sensitivity coefficient YdeltaT and relative tooth root fillet sensitivity coefficient YdeltarelT
13.1 Basic definition
13.2 Definitions of various tooth root fillet sensitivity coefficients
13.2.1 Overview
13.2.2 Method A
13.2.3 Method B
13.3 Method B Relative Tooth Root Fillet Sensitivity Coefficient YdeltarelT
13.3.1 Graphical values
13.3.2 Analytical value
14 Tooth root surface condition coefficient YR, YRT and relative tooth root surface condition coefficient YRrelT
14.1 The effect of surface conditions
14.2 Surface condition factor and relative surface condition factor
14.2.1 Overview
14.2.2 Method A
14.2.3 Method B
14.3 Relative surface condition factor YRrelT. Method B
14.3.1 Graphical values
14.3.2 Analytical Value
15 Size factor YX
15.1 Overview
15.2 Method A dimension factor YX
15.3 Method B size factor YX
15.3.1 Overview
15.3.2 Graphical values under ultimate durability and static strength
15.3.3 Analytical value
Appendix B (informative appendix) Reference value of average stress influence coefficient YM
Appendix C (informative appendix) Deduction formula for determining normal load of spur gear

1 Scope

This part of GB/T 3480 specifies an involute with a certain rim thickness (external tooth SR >0.5ht and internal tooth SR >1.75mn)

The basic formula for calculating the bending stress of cylindrical inner and outer spur gears and helical gears. This section considers all the loads caused by the gears

The factors that affect the root stress of the tooth can be quantitatively evaluated. In practice, internal gears may have a failure shape that is different from gear bending fatigue.

Enough safety assessment.

This part includes experimental tests and theoretical research conducted by Hirt [11], Strasser [14] and Brossmann [10]. Calculation

The results are consistent with other methods (references [5], [6], [7] and [12]). The formulas given in this section are applicable to comply with GB/T 1356 by

The tooth profile of the cylindrical gear processed by the basic rack-type tool can also be used for the equivalent gear end surface coincidence epsilonalphan is less than 2.5 and can be combined with other basic racks.

Conjugate tooth profile.

The bearing capacity derived from the allowable bending stress is called the "bending strength of gear teeth". This method of calculating the intensity is similar to other similar methods.

The method results are consistent, which has been explained in the "scope" in ISO 6336-1.

If this section is not applicable, refer to Chapter 4 of ISO 6336-1.2019.

2 Normative references

The following documents are indispensable for the application of this document. For dated reference documents, only the dated version applies to this article

Pieces. For undated reference documents, the latest version (including all amendments) is applicable to this document.

GB/T 1356-2001 Standard basic rack tooth profile for cylindrical gears for general machinery and heavy machinery (idtISO 53.1998)

GB/T 3374.1-2010 Gear terms and definitions Part 1.Geometric definitions (ISO 1122-1.1998, IDT)

GB/T 3505-2009 Product Geometric Technical Specification (GPS) Surface structure profile method terms, definitions and surface structure parameters (ISO 4287.1997, IDT)

GB/T 10610-2009 Geometric Technical Specifications for Products (GPS) The rules and methods of surface structure profile method for evaluating surface structure

Method (ISO 4288.1996, IDT)

ISO 6336-1 spur gear and helical gear load capacity calculation part 1.basic principles, overview and general influence coefficient (Calcula- tionofloadcapacityofspurandhelicalgears-Part 1.Basicprinciples,introductionandgeneralinflu- encefactors)

ISO 6336-5 spur gears and helical gears load capacity calculation part 5.material strength and quality (Calculation of load capacityofspurandhelicalgears-Part 5.Strengthandqualityofmaterials)

GB/T 10087 | GB/T 10086 | GB/T 6404.2 | GB/Z 3480.4 | GB/T 3480.5 | GB/T 3480.2 | […]

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This preview omits tables, figures, formulas and parts of the technical clauses. The complete document — 91 pages — is available in the English PDF.

Referenced standards

Normative references

ISO 1122 · ISO 4287.1997 · ISO 4288.1996 · ISO 6336

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