Case Study: engineering and industrialization of an accordion-type spring for a one-way roller clutch

By Santiago Galindo, R&D at RPK Technological Center

We focus on designing and industrializing high-precision springs for automotive use. For this project, our team worked closely with a global automotive and bearing company to develop a custom accordion spring for a one-way clutch. These clutches transmit torque in one direction and spin freely in the other. Here, we’ll walk through how we used advanced simulation, in-house tooling, and fast manufacturing to meet the challenge.

The Challenge: Designing an optimal spring for a One-Way Clutch

Our customer needed a spring for a one-way clutch that could withstand demanding performance conditions. It had to transmit high torque, withstand frequent engagement, and maintain low resistance during free rotation. The main requirements were:

• High torque and frequent engagement: The spring had to reliably handle strong torque and quick, repeated cycles.
• Low-drag torque and reduced inertia: Our goal was to minimize friction during free rotation by using a low-mass spring to keep inertia low and ensure a fast response.
• Precision and durability: The spring needed to keep its force and accuracy over its whole life, with almost no load loss even after 10,000 cycles.
• Scalable manufacturing: We also had to make sure the accordion spring, with its loops and eyelets, could be made in large volumes while keeping quality and tolerances tight.

FEA Simulation to validate the design

We used advanced Finite Element Analysis (FEA) to check and improve the spring design before making any parts. Our team simulated real working conditions for the clutch, examining stress distributions and local stress concentrations, especially in bends and corners. This let us fine-tune the shape and material use before we started cutting steel.

After several FEA rounds, we ensured the spring remained within the steel's elastic range so it would not deform. With the design validated in simulation, we moved to prototyping, confident that the spring would hit our targets for torque, fatigue, and deflection.

In-House tooling and high-speed forming

Moving from prototype to mass production was a real challenge due to the spring’s complex shape and stringent requirements. Our tooling workshop and Technological Center teamed up to build a custom multislide forming tool capable of producing the accordion shape with high precision. The spring’s loops and eyelets were made possible by our experience with multislide technology and precision bending.

Initially, we produced approximately 1,000 parts per hour. After optimizing tooling and process parameters, we increased output to 3,500 parts per hour. Strict quality control was maintained, including 100% camera inspection to ensure compliance with specifications. Our ability to design tooling in-house and control every stage of manufacturing was key to achieving both the required part complexity and production efficiency.

Conclusion: a high-performance spring

By bringing together advanced simulation, smart tooling, and precise manufacturing, we designed and produced a high-performance accordion spring for this key one-way clutch. The spring delivers high torque with low friction, helping our customers boost energy efficiency and ensure reliable engagement. This project demonstrates how RPK Group can deliver custom spring solutions for even the most demanding industry needs.