How to choose a rod end: A technical guide for design engineers

Rod ends are precision components designed to enable multidirectional angular and rotational movements between two parts. Thanks to their structure – comprising an inner spherical ring housed in an outer casing – they can handle a wide range of application challenges, from heavy loads to constant vibrations.

Rod ends are used in a variety of sectors, from industrial automation to mechanical handling. However, not all rod ends are created equal: selecting the right one is essential to ensure reliability, service life, and optimal mechanical performance.

Each application requires a thorough technical analysis to identify the most suitable product based on operating conditions, environment, and maintenance needs.

Below is a technical guide to help you navigate the various options available, with practical information on the key parameters to consider when making your selection.

Speed and load

Two of the most critical factors are rotational speed and applied load. Not all rod ends can handle both effectively, so it’s important to define the application’s dynamic profile early on.

• For high rotational speeds with moderate loads, rod ends with ball bearings are preferred, as they ensure smooth and precise operation.
• When speed is high and loads are heavy, rod ends with roller bearings should be used, as they distribute the load over a larger contact area.
• For very heavy loads at low speeds, sliding-type rod ends are ideal. They can withstand static stress and maintain a long service life, even in slow cycles.

Rollon Group’s offering includes the Premium line (with ball or roller bearings) and the Tescubal® series, both compliant with DIN ISO 12240-4, suited for high-speed dynamic applications. The Classic series is ideal for high loads, while the Basic and Tesno® lines are designed for medium loads and lower speeds.

Type of motion

Rod ends may be subject to continuous rotation, swivelling motion, or both.

• For full rotary movements and large swivelling angles, designs with geometries that minimise friction and extend service life are recommended.
• For limited swivelling motion, sliding-type rod ends are suitable, as they are optimised for low-amplitude alternating movements.

The Premium and Tescubal® lines stand out for their wide range of motion and ability to support large turning angles. The Classic series is well-suited to more restricted movement, while the Basic and Tesno® lines are designed for smaller oscillations.

Maintenance and lubrication

During the design phase, it’s essential to evaluate whether regular maintenance will be feasible:

• If periodic lubrication is possible, rod ends with integrated lubrication systems are recommended, as they allow the use of specific technical greases.
• In maintenance-free systems, self-lubricating materials or lubrication-free technologies are the better choice.

Premium rod ends feature an integrated lubrication system for easy upkeep.

The Classic line uses a maintenance-free plastic polymer.

Tescubal® rod ends employ sintered bronze – a porous material infused with oil –ideal for maintenance-free operation.

The Tesno® and Basic series use a PTFE layer between the ball and the housing, providing a good balance between cost and performance in maintenance-free applications.

Operating environment and durability

Factors such as materials, surface contact, working environment, cycle frequency, and backlash directly affect long-term performance. Key considerations include:

• In dusty or contaminated environments, choose a system that tolerates particle ingress without compromising functionality.
• In corrosive or humid environments, opt for corrosion-resistant materials that maintain stable performance over time.
• For long service life, consider how internal backlash will evolve over time.

The Classic series performs well in contaminated environments, while the Tescubal® series – with a bronze bushing and steel body – is more suitable for corrosive conditions. Both are also available in stainless steel for enhanced resistance.

Working temperature

Operating temperature significantly impacts rod end performance and durability.

• Standard solutions typically operate between 60°C and 120°C.
• For applications with peaks up to 200°C, special versions should be used.

The Tesno® and Basic series operate effectively up to 200°C.

The Premium and Tescubal® lines are designed for moderate temperatures up to 120°C, while the Classic line is suitable up to 60°C.