ISO 10828:2024

Overview - ISO 10828:2024 (Worm gears - Worm profiles and gear mesh geometry)

ISO 10828:2024 defines the geometry and axial thread profiles for the five most common worm profile types - A, C, I, K and N - and provides the mathematical basis needed to describe worm gear mesh geometry. The standard supplies formulae for axial profiles, the path of contact, the conjugate profile of the worm wheel, lines of contact, radii of curvature and point velocities. It also links these geometric results to practical load capacity calculations (see clause 11.11).

Keywords: ISO 10828:2024, worm gears, worm profiles, gear mesh geometry, worm wheel, axial profile, load capacity

Key technical topics and requirements

• Profile types: Definitions and geometric characterization of the five profile types (A, C, I, K, N), including recommended machining methods.
• Formulae and parameters: Comprehensive formulae for worm and worm wheel parameters (axial pitch, module, lead, reference diameters, addendum/dedendum, thread thickness, etc.).
• Meshing geometry: Calculation methods for centre distance, pitch diameters, gear ratio, contact ratio and start/end of active profiles.
• Contact mechanics inputs: Equations to compute the path of contact, conjugate worm wheel profile, lines of contact, radii of curvature and relative velocities at contact points - important inputs for stress and wear analysis.
• Section planes and coordinates: Definitions of axial, transverse, offset and normal sections to support accurate geometry generation and inspection.
• Implementation guidance: Initialization algorithms and general formulae for axial profiles, with cross-references to load-capacity parameter calculations (clause 11.11).

Practical applications and who uses this standard

ISO 10828:2024 is essential for professionals and organizations involved in worm gear design, manufacture and verification:

• Gear designers and mechanical engineers creating worm drives for gearboxes, actuators, cranes and steering systems.
• Manufacturers and CNC tool programmers defining machining profiles and quality controls.
• CAD/CAM and simulation engineers generating accurate 3D models for finite-element analysis (FEA) and contact/wear simulations.
• Test laboratories and inspection teams verifying gear geometry, contact conditions and conformity to industry practice.
• Standards committees and procurement specialists specifying consistent, interchangeable worm gear geometry.

Practical benefits include improved accuracy of gear pair design, consistent geometry for manufacturing and inspection, better inputs for load-capacity and lifetime estimations, and reduced risk of mis-mating or premature wear.

Related standards

ISO 10828:2024 complements other gear geometry and testing standards that govern terminology, gear tooth calculations and inspection practices. When specifying worm gear systems, combine ISO 10828 with applicable gear quality and material standards to ensure full design and verification coverage.