Retaining Rings & E-clips Dimensions Lookup

Standard Size Chart

Engineering Standard & Assembly Guidelines for Retaining Rings & E-clips

Retaining rings (also known as snap rings or circlips) and E-clips are standard fastening elements used to secure components axially on shafts or inside bores. Designing precise groove dimensions is key to preventing assembly failure.

1. Types and Design Differences

• External Retaining Rings for Shafts (GB/T 894): Installed in external shaft grooves. The ring grips the groove bottom radially due to inward elastic force, preventing axial movement of matching parts.
• Internal Retaining Rings for Bores/Holes (GB/T 893): Fitted inside internal bore grooves. The outward tension locks it in place, widely used for bearing location.
• Radial E-clips for Shafts (GB/T 896): Featuring an E-shaped profile, these clips can be slid radially into shaft grooves without requiring snap ring pliers. Ideal for low-load applications with tight spaces.

2. Critical Machining Requirements

• Groove Diameter d₂: The outer/inner diameter of the cut groove. If the groove is too shallow, the retaining ring won't expand/contract completely, risking pop-out. If too deep, it reduces the shaft/housing load-carrying capacity.
• Groove Width m: The axial width of the groove. Typically, grooves are machined about 0.1 to 0.2 mm wider than the standard ring thickness t. The edges of the groove must remain sharp to ensure maximum axial thrust retention.
• Groove Depth n: The theoretical single-sided depth of the groove, representing the feed increment for cutter setup.

3. Prevention of Thrust Failure

Under high-speed rotation or impact loading, snap rings can escape their grooves. If a system is subjected to high axial loads, it is recommended to use spacer sleeves or locknuts instead of relying solely on standard elastic retaining rings.