ISO 6194-1:2007

Overview

ISO 6194-1:2007 specifies nominal dimensions and tolerances for rotary shaft lip-type seals incorporating elastomeric sealing elements. It covers seal types and examples, dimensional identification codes and the required dimensions and tolerances for seals, shafts and housings. The standard is intended for low-pressure dynamic sealing applications (typically 0 kPa to 30 kPa / 0.3 bar above atmospheric) where an interference fit between seal, shaft and housing provides sealing and retention.

Key topics and technical requirements

• Seal types and lip arrangements: Illustrates four basic outside‑diameter constructions (metal‑cased, semi‑rubber‑covered, rubber‑covered etc.) and common sealing lip layouts (single lip, single lip with protection lip).
• Nominal dimensions: Provides standardized nominal diameters and seal widths for common sizes and a dimensional identification code for part identification.
• Pressure range: Designed for low differential pressures; users should consult manufacturers for higher pressures.
• Shaft requirements:
  • Lead‑in chamfer and burr‑free ends to protect sealing lips during assembly.
  • Diametral tolerance not greater than h11 (ISO 286‑2).
  • Surface roughness (axial): typically Ra 0.2–0.5 µm, Rz 1.2–3.0 µm (ground shafts); agreement may be needed for alternative finishes.
  • Surface hardness: minimum 30 HRC, or 45 HRC where handling damage is a risk.
• Housing (bore) requirements:
  • Lead‑in chamfer, depth and corner radius specified to match seal types.
  • Diametral tolerance not greater than H8 (ISO 286‑2).
  • Bore roughness (axial): typically Ra 1.6–3.2 µm, Rz 6.3–12.5 µm; no visible imperfections allowed.
• Seal tolerances:
  • Seal width tolerances vary by nominal width (for example ±0.3 mm for small widths up to ±0.6 mm for larger widths).
  • Outside‑diameter tolerances and roundness tolerances are specified to ensure correct interference fit with ferrous housings; consult seal supplier for non‑ferrous housings.
• Installation and identification: Includes recommendations for lead‑in geometry and refers to ISO 6194‑3 for storage, handling and assembly tools. Also specifies identification statements and sizing codes.

Applications and users

ISO 6194-1 is used by:

• Seal manufacturers and suppliers (design and quality control)
• Machine designers and OEMs (rotating equipment, gearboxes, pumps, motors)
• Maintenance and reliability engineers specifying replacement seals
• Procurement and inspection teams for dimensional acceptance

It is particularly relevant for equipment requiring low‑pressure dynamic seals where repeatable dimensions, interference fits and surface finishes are critical to service life.

Related standards

• ISO 6194 (Parts 2–5): vocabulary, storage/installation, performance tests, visual imperfections
• ISO 16589: seals with thermoplastic elements (complementary)
• ISO 286‑2: limits and fits (h11, H8)
• ISO 5598: fluid power vocabulary

Keywords: ISO 6194-1, rotary shaft lip-type seals, elastomeric sealing elements, nominal dimensions, tolerances, shaft surface roughness, housing bore, interference fit.