Keyed connections are the traditional method for securing rotating shafts to power transmission components, such as gears, sprockets, and lever arms. The basic principle behind a keyed connection is the use of a key, a small, metal component that fits into a keyway in both the shaft and the hub of the connected parts. The key locks the two parts together, preventing them from slipping or rotating independently of each other. 

In contrast to keyed connections, keyless connections use friction or other methods to secure the shaft and hub together without the need for a key. Instead of relying on a key to transmit torque, keyless connections use an interference fit, where the components are tightly pressed together using mechanical force, to handle applications with inconsistent power. This can be achieved through various mechanisms, such as split hubs, clamping rings, or bushing-type connections.

When to use keyed vs. keyless connections

The choice between keyed and keyless connections depends on several factors, including the specific needs of the application:

• Keyed connections are often the best choice for standard or lower-torque applications where cost-effectiveness and ease of maintenance are important. They are suitable for many industrial machines, where the torque requirements are moderate, and where ease of repair and replacement is a priority.
• Keyless connections are ideal for high-torque, high-performance applications, such as in motors, turbines, or aerospace components, where precision, reliability, and longevity are critical. They provide superior torque transfer, reduced wear, and improved alignment, making them worth the extra cost in demanding environments.

Both keyed and keyless connections offer advantages when applied in the power transmission world. Understanding the trade-offs in terms of cost, performance, and long-term reliability is key to making the right choice for your system. While keyed connections remain a trusted, cost-effective solution for many applications, keyless connections offer superior performance and durability in demanding, high-torque environments.

By carefully considering the specific needs of your application, you can make an informed decision about whether keyed versus keyless connection is the right choice for your application.

Download our eBook about gearbox selection to learn more or contact us at (888) 786-2371 or email sales@stober.com for help determining what gearbox is most appropriate for your application.