ISO 9982:2021

Overview

ISO 9982:2021 - "Belt drives - Pulleys and V-ribbed belts for industrial applications - PH, PJ, PK, PL and PM profiles: dimensions" specifies the principal dimensional characteristics and inspection tolerances for V‑ribbed pulley grooves and corresponding endless V‑ribbed belts used in general industrial applications (excluding elastic belts). The standard covers the PH, PJ, PK, PL and PM profiles (note: the PK profile originated in automotive accessory drives; ISO 9981 addresses that field).

Key topics and technical requirements

• Profile dimensions: Groove/rib pitch and geometry are defined for each profile:
  • Groove pitch e (pulley): PH 1.6 ±0.03 mm, PJ 2.34 ±0.03 mm, PK 3.56 ±0.05 mm, PL 4.7 ±0.05 mm, PM 9.4 ±0.08 mm.
  • Groove/rib angle: 40° for all profiles.
• Pulley groove radii and limits: Minimum/maximum groove and transitional radii are specified per profile (see standard tables for exact values).
• Minimum effective pulley diameter: PH 13 mm, PJ 20 mm, PK 45 mm, PL 75 mm, PM 180 mm.
• Tolerances and run‑out:
  • Groove‑to‑groove diameter variation limits depend on effective diameter and number of grooves (incremental allowances per additional groove).
  • Radial circular run‑out limits (full indicator movement): e.g., ≤74 mm → 0.13 mm; 74–250 mm → 0.25 mm; >250 mm → 0.25 mm + 0.0004 mm per mm over 250.
  • Axial run‑out: 0.002 mm per mm of effective diameter.
  • Diameter‑over‑balls tolerances: K ≤75 mm ±0.3 mm; 75<K≤200 mm ±0.6 mm; add ±0.1 mm per additional 25 mm.
• Surface finish: Pulley groove roughness Ra ≤ 3.2 μm (references ISO 254 / ISO 4287).
• Belt dimensions (rib pitch p, rib tip/bottom radii, belt height h):
  • Rib pitch p matches pulley pitch values above.
  • Belt heights approximately PH 3 mm, PJ 4 mm, PK 6 mm, PL 10 mm, PM 17 mm.
  • Nominal belt width b = number of ribs × rib pitch.
• Inspection & measurement: Procedures for measuring effective belt length, centre distance variation and specifying measuring forces/fixtures are defined.

Practical applications

• Ensures interchangeability of V‑ribbed belts and pulleys across manufacturers.
• Guides mechanical designers selecting pulley sizes and calculating speed ratios (use effective line differential b values specified per profile).
• Supports quality control, acceptance testing and dimensional inspection in manufacturing and maintenance.
• Useful for procurement specifications, spare‑parts matching, and OEM vs aftermarket compatibility checks.

Who should use this standard

• Pulley and belt manufacturers, product designers, power transmission engineers, maintenance teams, quality inspectors, test laboratories and buyers specifying industrial belt drives.

Related standards

• ISO 9981 (automotive accessory drive - PK-specific matters)
• ISO 254, ISO 4287 (surface roughness definitions and measurement)
• ISO 8370 series (further belt/pulley fitting and performance information)

Keywords: ISO 9982:2021, V‑ribbed belts, pulleys, PH PJ PK PL PM profiles, belt drives, dimensions, tolerances, groove pitch, effective diameter, surface roughness.