A guide to retaining ring styles

3 mins read

Retaining rings, unassuming but critical components in the world of engineering and mechanics, come in various forms, each with its unique characteristics and advantages.

Image credit: Rotorclip

Whether it’s an internal or external, spiral, tapered or constant section ring, they are an essential component in an assembly and selecting the right style and assembly method is crucial. Rotorclip has uploaded a guide that delves into the diverse world of retaining rings, shedding light on their features and benefits.

Tapered Section Rings – Axial

Tapered section retaining rings, also known as circlips, feature a tapered design where the radial width of the cross-section decreases from opposite the gap down towards the lugs. This profile allows the ring greater radial flex to tightly grip the bottom of the groove, equipping it to withstand significant thrust loads. Functioning as a lightweight alternative to traditional fasteners such as screws, nuts, and bolts, these rings can handle substantial forces in a properly designed application.

In applications where factors such as vibration, movement or noise necessitate attention, alternative tapered section ring designs can alleviate these concerns. Bowed and beveled retaining rings utilise the spring properties of the ring to effectively counteract the impact of accumulated tolerances, assembly wear, and endplay.

Most axial assembled retaining rings feature lugs and lug holes, offering ease of installation and removal. Simple automation allows for the ring to be expanded over a mandrel for positioning in the groove and is recommended for high volumes or when repeatability of installation is important. This streamlined process simplifies assembly procedures, reducing production timelines and ultimately yielding a reduction in labour costs.

This ring is a versatile option that can be used in both internal and external applications, meeting functional, safety and reliability requirements across diverse industries and applications.

Tapered Section Rings – Radial

Radial retaining rings combine simplicity, choice of configurations and functional design into one solution. Engineered for applications requiring low thrust loads, they are designed for when radial installation is imperative due to interference from other components.

Radially installed rings are available in various styles including e-rings, c-rings and poodle rings, in configurations to suit a variety of assembly requirements. The added benefit is that radial retaining rings are often considered a cost-effective alternative to their axial counterpart.  Since radial rings do not need to flex as much as an axial ring during installation, they can also offer greater contact with a retained part when designing smaller assemblies.

Similar to axial rings, there are options for bowed configurations that effectively counteract vibration and shock impact. The spring-like nature of the rings enables them to absorb movement, reducing the transmission of these forces to the rest of the assembly.

Installation is simple as radial retaining rings can be conveniently snapped into place using specialised applicators which can be mated in automated installation lines. This streamlined process adds to their appeal, ensuring efficient integration into any assembly.

Constant Section Rings/Snap Rings

Constant section rings, commonly known as snap rings, exhibit a consistent width (or radial wall) along their entire circumference, typically establishing three points of contact within the groove. This uniformity guarantees a steady, unvarying interface that serves as a shoulder, firmly anchoring an assembly in position. These rings excel in scenarios with restricted clearances or confined spaces, thanks to their lug-free design.

Constant section/snap rings are frequently chosen for their robust cross-section, bolstering their capacity to effectively withstand impact loads, making them a preferred choice in applications where strength and durability is paramount.

Self-Locking/Push-On Rings

Self-locking/push-on retaining rings offer a comprehensive solution combining small size, ease of installation and security.

These rings incorporate notches or indentations around the inner or outer diameter, ensuring the ring remains securely in place, even when vibrations or dynamic loads are present, maintaining the integrity of the assembly.

Self-Locking/push-on rings can operate without the need for grooves or complex machining in the mating components. This simplifies design and manufacturing process, making them an efficient choice for applications that demand simplicity without compromising on performance.

suitable for applications with very low thrust loads, they are available in several configurations making them adaptable and versatile.

Spiral Retaining Rings

Much like their more conventional counterparts, spiral rings serve as an artificial shoulder seated within a groove on a shaft or contained within a housing. This design ensures precision and stability in mechanical assemblies.

What sets spiral rings apart is their coiled structure, which grants them an exceptional degree of flexibility when it comes to sizing and material selection. In multiple turn construction, the ring provides 360° contact with the groove. Spiral rings provide comprehensive retention capabilities without the need for assembly lugs.

Spiral rings are easy to install and remove, requiring no specialised tools. They can be smoothly wound into the groove by hand. For high-speed automated assembly, simple tooling can be employed to streamline production processes. For removal, spiral rings come equipped with a convenient removal notch or scallop, accessible with a basic screwdriver.

Notably, the efficiency of spiral rings also extends to minimising waste in manufacturing and assembly processes. Their coiled design can result in efficient scrap minimisation techniques, saving cost and environmental concerns.