ISO 10300-2-2023 (2025) PDF

Full title and description

ISO 10300-2:2023 — Calculation of load capacity of bevel gears — Part 2: Calculation of surface durability (macropitting). This international standard specifies formulae, symbols and procedures for rating the surface durability (macropitting) of straight, helical (skew), spiral bevel, Zerol and hypoid gears and clarifies the limits and factors that influence surface failure under load.

Abstract

This document provides the methods of calculation of load-carrying capacity with formulae and symbols for determining surface durability (macropitting) of bevel gears. It establishes a rating system based on virtual cylindrical gears, lists applicability (types of bevel gears and tooth forms), and notes conditions and limits where results should be confirmed by experience (for example large mean spiral angles, high effective pressure angles or very large facewidths).

General information

• Status: Published.
• Publication date: 24 August 2023 (corrected version — English: April 2025).
• Publisher: ISO (International Organization for Standardization).
• ICS / categories: 21.200 (Gears).
• Edition / version: Edition 3 (2023).
• Number of pages: 35.

Scope

ISO 10300-2:2023 applies methods for calculating surface load capacity (macropitting) of bevel gears including straight, helical (skew), spiral, Zerol and hypoid designs, for both tapered-depth and uniform-depth teeth. The rating system is based on virtual cylindrical gears and is restricted to bevel gears whose virtual cylindrical gears have transverse contact ratio ε_vα < 2 and where the sum of profile shift coefficients of pinion and wheel is zero (see ISO 23509). The standard is not applicable to gears with an inadequate contact pattern under load and cautions users to confirm results experimentally for extreme geometries or pressure angles.

Key topics and requirements

• Formal calculation methods and formulae for surface durability (macropitting) of bevel gears.
• Definition and use of symbols, factors and correction coefficients used in rating calculations.
• Applicability to straight, helical (skew), spiral, Zerol and hypoid bevel gears (tapered and uniform depth).
• Limitations and cautions: transverse contact ratio (ε_vα < 2), sum of profile shift coefficients = 0 (see ISO 23509), and warnings for extreme spiral angles, pressure angles or very large facewidths.
• Relation to other parts of the ISO 10300 series (rating approach consistency and cross-references).

Typical use and users

Engineers and designers of bevel and hypoid gearsets use this standard to assess and compare surface durability (macropitting) for gear design, material selection, and lubrication decisions. Manufacturers, test laboratories, tribologists, gear specialists, and technical committees adopt the methods for product development, verification and failure analysis. The standard is also used in academic and research contexts when modelling gear surface fatigue.

Related standards

Key related documents include other parts of the ISO 10300 series (for example ISO 10300-1:2023 — Introduction and general influence factors, and ISO 10300-3:2023 — tooth root strength calculations), the ISO 23509 family on bevel and hypoid gear geometry (which provides geometry and profile-shift conventions referenced by ISO 10300), and ISO/TR/ISO 10300-30 (sample calculations and worked examples). These documents together form the recommended framework for bevel-gear rating and geometry input.

Keywords

bevel gears, macropitting, surface durability, load capacity, gear rating, hypoid, spiral bevel, Zerol, profile shift, contact ratio, ISO 10300, ISO 23509.

FAQ

Q: What is this standard?

A: ISO 10300-2:2023 is Part 2 of the ISO 10300 series providing calculation methods and formulae to evaluate surface durability (macropitting) of bevel and hypoid gears.

Q: What does it cover?

A: It covers formulae, symbols, and factor definitions for rating surface durability (macropitting) of straight, helical (skew), spiral, Zerol and hypoid bevel gears; specifies applicability limits and notes conditions where calculated results should be confirmed by experience.

Q: Who typically uses it?

A: Gear designers, mechanical engineers, manufacturers, testing and failure-analysis laboratories, tribologists, and standards committees use the standard for design verification, specification and comparative assessment.

Q: Is it current or superseded?

A: Current — ISO 10300-2:2023 (3rd edition) was published 24 August 2023 and replaced earlier editions (for example the 2014 edition). A corrected English version is recorded in April 2025.

Q: Is it part of a series?

A: Yes — it is one part of the ISO 10300 series on calculation of load capacity of bevel gears; other parts include ISO 10300-1 (general factors), ISO 10300-3 (tooth root strength), and additional related parts for worked examples and other failure modes.

Q: What are the key keywords?

A: Bevel gears, macropitting, load capacity, surface durability, gear rating, hypoid, spiral, profile shift, contact ratio, ISO 10300.