GB/Z 3480.31-2025Calculation of load capacity of spur and helical gears - Part 31: Calculation examples of micropitting load capacity (English PDF)

Foreword

This document is a report-type guidance technical document.

This document complies with the provisions of GB/T 1.1-2020 "Standardization Work Guidelines Part 1: Structure and Drafting Rules of Standardization Documents". Drafting.

This document is Part 31 of GB/T (Z)3480 "Calculation of Load Capacity of Spur Gears and Helical Gears". GB/T (Z)3480 has been published. The following parts were included.

---Part 1: Basic Principles, Overview, and General Influence Coefficients;

---Part 2: Calculation of tooth surface contact strength (pitting);

---Part 3: Calculation of Gear Tooth Bending Strength;

---Part 4: Calculation of Tooth Surface Fracture Bearing Capacity;

---Part 5: Strength and Mass of Materials;

---Part 6: Service life calculation under variable load conditions.

---Part 20: Flash Method for Calculating the Load-Bearing Capacity of Adhesive Bonds;

---Part 21: Calculation of Bonded Load Capacity Using the Accumulated Temperature Method;

---Part 22: Calculation of the bearing capacity of micropitting corrosion;

---Part 31: Example of micropitting load-bearing capacity.

This document is equivalent to ISO /T R6336-31.2018 "Calculation of load-carrying capacity of spur and helical gears - Part 31: Load-carrying capacity of micropitted gears". "Capacity Calculation Example". The document type has been changed from an ISO technical report to a national standardization guidance technical document of my country.

The following minimal editorial changes have been made to this document.

---In Table 2, "KBY" should be corrected to "KBgamma";

---Added some references to formulas in the text.

Introduction

GB/T (Z)3480, "Calculation of Load Capacity of Spur Gears and Helical Gears," is widely used in my country's gear industry. These standards constitute... The calculation system for the load-bearing capacity of involute cylindrical gears in my country helps to fully align the reliability design of Chinese gear products with international standards.

GB/T (Z)3480 describes the calculation method for the load-carrying capacity of involute cylindrical spur gears and helical gears. It is currently proposed to be divided into 11 parts.

The research objects and calculation methods of each are different, and their contents are related to each other but also independent.

---Part 1: Basic Principles, Overview, and General Influence Coefficients. The purpose is to describe the load-carrying capacity of involute cylindrical spur gears and helical gears.

The basic principles of force calculation are explained, and the values of the general influence coefficient and some correction coefficients are given.

---Part 2: Calculation of Tooth Surface Contact Strength (Pittling). The purpose is to describe the tooth surface contact strength (pitting) based on Hertzian contact theory.

The calculation method for corrosion is given, and the values of some correction coefficients are provided.

---Part 3: Calculation of Tooth Bending Strength. The purpose is to describe a method for calculating the tooth surface bending strength based on cantilever beam theory, providing... The values of the partial correction coefficients are given.

---Part 4: Calculation of Tooth Surface Fracture Capacity. The purpose is to describe methods developed in recent years for assessing the risk of tooth surface fracture.

---Part 5: Material Strength and Quality. The purpose is to provide technical requirements for different material quality grades and their impact on gear tooth surface contact.

The main factors and allowable values of the ultimate limit of contact strength and the ultimate limit of tooth root bending strength.

---Part 6: Service Calculation under Variable Loading Conditions. The purpose is to describe the service life calculation using the Palmger-Miner method under variable loading conditions. The method for calculating the equivalent value of variable load.

---Part 20: Calculation of Bond Load Capacity using the Flash Temperature Method. The purpose is to describe the method for calculating the maximum contact temperature of meshing tooth surfaces.

The variation of contact temperature along the contact path, and the evaluation of bonding.

---Part 21: Calculation of Adhesive Load-Bearing Capacity using the Accumulated Temperature Method. The purpose is to describe the increase in contact temperature along the contact path of the meshing tooth surfaces.

The calculation method of weighted average value and the evaluation of adhesive bonding.

---Part 22: Calculation of Micropitting Capacity. The purpose is to describe the minimum oil film thickness of a specific lubricant in the gear contact area. Calculation methods and evaluation of gear resistance to micropitting.

---Part 30: Application examples of Parts 1, 2, 3, and 5 of GB/T 3480. The purpose is to provide standard users with examples based on... Calculation examples that can be referenced in GB/T 3480.1, GB/T 3480.2, GB/T 3480.3 and GB/T 3480.5 standards.

---Part 31: Micropitting Carrying Capacity Examples. The aim is to provide standard users with a reference based on GB /Z 3480.22. Calculation example.

1 Scope

The examples provided in this document are for guidance purposes only and should not be taken as definitive statements.

Permissible values for gear materials or lubricants, or recommendations based on the micro-geometry in practical applications. For a given operating condition, it is advisable to refer to ISO /TS.

The method in 6336-22 determines the necessary parameters and allowable film thickness ratio (lambdaGFP).

2 Normative references

The contents of the following documents, through normative references within the text, constitute essential provisions of this document. Dated citations are not included.

For references to documents, only the version corresponding to that date applies to this document; for undated references, the latest version (including all amendments) applies. This document.

GB /Z 3480.22-2024 Calculation of Load-Bearing Capacity of Spur Gears and Helical Gears - Part 22: Calculation of Load-Bearing Capacity for Micropitting (ISO /T S6336-22.2018, IDT)

Note: GB/T 3374.1-2010 Gears - Terminology and Definitions - Part 1: Geometric Definitions (ISO 1122-1:1998, IDT)

ISO 6336-1 Calculation of load-carrying capacity of spur and helical gears - Part 1: Basic principles, overview and general influence coefficients (Calcula-encefactors)

Note: GB/T 3480.1-2019 Calculation of load-carrying capacity of spur and helical gears - Part 1: Basic principles, overview and general influence coefficients (ISO 6336-1. 2006, IDT)

ISO 6336-2 Calculation of load-carrying capacity of spur and helical gears - Part 2: Calculation of fatigue strength (pitting) of tooth surface contact ting)]

Note: GB/T 3480.2-2021 Calculation of load-carrying capacity of spur and helical gears - Part 2: Calculation of tooth surface contact fatigue strength (pitting) (ISO 6336-2. 2019, IDT)

ISO /T S6336-22 Calculation of Carrying Capacity of Spur and Helical Gears - Part 22: Calculation of Carrying Capacity for Micropitting andgearpairs-Conceptsandgeometry)

The terms and definitions defined in ISO 1122-1, ISO 6336-1 and ISO 6336-2 apply to this document.

4 Symbols and Units

The symbols in Table 2 apply to this document. The length units m, mm, and µm are chosen according to general convention.