Overview
ISO/TR 10300-32:2021 - "Calculation of load capacity of bevel gears - Part 32: ISO rating system for bevel and hypoid gears - Sample calculation for scuffing load capacity" is an informative Technical Report that provides worked example calculations for scuffing (adhesive wear) load capacity of bevel and hypoid gears. It illustrates the application of the scuffing calculation method given in ISO/TS 10300-20 (Flash temperature method) and uses initial gear geometry defined by ISO 23509. The report is part of the ISO 10300 series that standardizes gear rating methods for surface durability and tribological behavior.
Key topics and technical requirements
- Scope and gear types: Applies to straight, helical (skew), spiral bevel, zerol and hypoid gears; where specific forms apply they are identified.
- Methodology demonstrated: Sample calculations implement the flash temperature method for scuffing load capacity as described in ISO/TS 10300-20, using a virtual cylindrical-gear representation of bevel gears.
- Sample content: Four detailed worked examples (Annexes A–D): one spiral bevel pair without hypoid offset and three hypoid gear set examples.
- Input data and parameters: Geometry per ISO 23509, material and lubrication properties, operating loads and speeds, surface roughness, and mounting/verification notes. Examples show computation of contact path, virtual cylindrical-gear parameters, contact temperatures, permissible contact temperature and scuffing safety factors.
- Limitations and applicability:
- Formulae are restricted to bevel gears whose virtual cylindrical gears have transverse contact ratios εvα < 2.
- Valid within the factor ranges specified in ISO 10300-1 (see also ISO 6336-2).
- Warning: for large mean spiral angles [(β1+β2)/2 > 45°], effective pressure angles α > 30°, or large face widths (b > 13·mn) the calculated results should be confirmed by experience.
Practical applications and users
- Gear designers and gearbox manufacturers - use the worked examples to validate scuffing assessments during design and material selection.
- Tribologists and lubrication engineers - apply the flash-temperature approach and sample calculations to evaluate lubricant selection and operating temperature effects.
- Test laboratories and quality engineers - use examples to set up test protocols and interpret scuffing safety factors.
- Standards engineers and researchers - reference the examples for implementing ISO/TS 10300-20 procedures or developing simulation tools.
Related standards
- ISO/TS 10300-20 - Calculation of scuffing load capacity (flash temperature method)
- ISO 23509 - Bevel gear geometry (initial geometry data used in examples)
- ISO 10300 series - broader set of parts for bevel/hypoid gear rating (pitting, root strength, tribology)
- ISO 6336-2 - referenced for influence factor ranges and validation notes
Keywords: ISO/TR 10300-32:2021, bevel gears, hypoid gears, scuffing load capacity, ISO/TS 10300-20, flash temperature, ISO 23509, virtual cylindrical gears, gear rating, sample calculations.