Slewing rings: without gearing, with internal or external gear, and how to select them

A slewing ring is a large-diameter bearing designed to support axial, radial loads and tilting moments simultaneously. Unlike conventional bearings, it is mounted directly between two structures and allows one to rotate relative to the other with high precision and rigidity.

It is used in applications requiring slow rotation or positioning, such as cranes, excavators, rotary tables, solar trackers, wind turbines, and medical equipment. Its compact design integrates gearing and mounting holes, simplifying assembly.

At MR Accesorios Industriales we distribute TECMA DRIVE slewing rings, with 186 references available for different configurations and sizes. If you need advice, we help you choose the right slewing ring for your application.

Slewing rings are classified according to the location of the gearing. The three main types are: without gearing, with internal gearing, and with external gearing. Each has advantages depending on the equipment design and the method of motion transmission.

Slewing rings without gearing are used when rotation is transmitted by other means, such as friction drives or cylinders. They are simpler and more economical, but require an external system to generate rotation.

Slewing rings with internal gearing have teeth on the inner diameter. They are ideal when the drive pinion must be located inside the central space, which protects the gearing and reduces overall size. Those with external gearing have teeth on the outer diameter, facilitating access to the pinion and allowing higher transmission ratios.

The ungeared slewing ring is a large-diameter bearing that does not include teeth on its rings. It is used in applications where rotation is achieved by other mechanisms, such as friction drives, hydraulic cylinders, or manual positioning systems.

This type is common in low-speed rotary tables, work platforms, and equipment where movement does not require gear transmission. Without gearing, its manufacturing is simpler and its cost can be lower.

An example code for an ungeared slewing ring is TD-W9-RA, which corresponds to a specific TECMA DRIVE series. If your application does not need gearing, this can be an efficient option.

In slewing rings with internal gearing, the teeth are machined on the inner diameter of the ring. This configuration allows the drive pinion to be placed inside the central space, which protects the gearing from contamination and reduces the overall size of the assembly.

They are widely used in cranes, excavators, and rotary tables where space is limited and a compact solution is sought. Additionally, with the gearing on the inside, better load distribution can be achieved in certain applications.

An example code is TD-R7-RL, which identifies a TECMA DRIVE slewing ring with internal gearing. When selecting, it is important to verify the module and number of teeth to ensure compatibility with the pinion.

Slewing rings with external gearing have teeth on the outer diameter of the ring. This is the most common configuration, as it facilitates access to the drive pinion and allows simpler assembly of the transmission system.

They are used in applications such as truck-mounted cranes, aerial work platforms, solar trackers, and road machinery. External gearing allows larger pinion diameters and, in general, better heat dissipation.

When choosing a slewing ring with external gearing, consider the module, number of teeth, and gearing quality. At MR Accesorios Industriales we quote TECMA DRIVE slewing rings with external gearing according to your needs.

Selecting a slewing ring requires analyzing the loads it will support: axial, radial, and tilting moment. These values are combined to calculate the equivalent load, which must be less than the dynamic or static load capacity of the bearing, depending on the application.

You also need to define the type of gearing (without gearing, internal, or external), the module and number of teeth, and the mounting dimensions (hole diameter, bolt circle, height). The working environment influences the choice of seals and lubrication.

At MR Accesorios Industriales we work with TECMA DRIVE slewing rings and help you select the right one. Send us the load data, dimensions, and type of gearing, and we will indicate the appropriate alternative.

Below we answer some common questions from buyers and maintenance managers. If you have specific doubts, contact us via WhatsApp or email and we will advise you promptly.

Remember that you can send us the code of the slewing ring you need to replace, the measurements, or a photo of the part. With that information we will quote the appropriate slewing ring for your equipment.