How does the main bearing contribute to the reliability and efficiency of wind turbines?

Wind energy is a central pillar of the energy transition and, at the same time, one of the most technically demanding technologies in the renewable energy sector. As turbines grow larger, towers become taller and rotor blades get longer, the power output per turbine increases. But so do the technical stresses on the drivetrain. As the component that bears the rotor loads and transmits forces and torques to the gearbox, the main bearing is critical to the availability, reliability and efficiency of the entire wind turbine.

Shorter development cycles and more condensed testing phases make failures of components such as the main bearing in wind turbines particularly critical, as they can lead to prolonged downtime, high maintenance costs and reputational damage.

When traditional bearings in wind turbines reach their limits

In many modern wind turbines, conventional roller bearings are reaching their limits: Frequent start-stop cycles, variable loads and high rotor torques lead to well-known failure mechanisms such as damage to rolling elements and raceways, fatigue and wear.

Repairs require complex crane operations and incur high costs, while long downtimes directly impact economic efficiency. Furthermore, the load capacity and maintenance requirements of roller bearings are limited by Hertzian contact. This is a clear weak point in larger, high-performance turbines.

Miba Segmented Journal Bearing (SJB^®) – The alternative for main bearings in wind turbines

The Miba Segmented Journal Bearing (SJB^®) addresses the key weaknesses of conventional bearings and offers scalable, low-maintenance main bearing solutions for modern wind turbines.

Thanks to segmented sliding surfaces, hydrodynamic load distribution and serviceability directly at the tower, the SJB^® reduces technical risks and significantly lowers the total cost of ownership (TCO).

Economic benefits of Miba SJB® – Reducing LCoE in wind turbines

The segmented hydrodynamic bearing optimizes the total cost of wind turbines through lower operating costs, a more compact system, scalable designs, and higher availability. It reduces failure rates, service costs, and the carbon footprint over the entire lifecycle.  Our main bearing is therefore ideal for new construction and repowering projects

• Optimized system costs (Capex):  The compact design allows for increased power output without raising system costs. Scalable for larger turbines.

• Increased energy yield (AEP) due to low failure rates, increased availability, and thus a more stable energy yield.

• Up-Tower maintenance eliminates the need for costly crane deployment, waiting times, and downtime.

• Scalable for larger turbines: enables higher power density and compact drives (15–20 MW+).

• Durability: Significantly longer service life thanks to the simple, robust design of our main bearings.

• Efficient condition monitoring: simple physical inspection. Real-time condition monitoring using conventional particle/temperature sensors, precise remaining life prediction using a methodology based on load collective data.

• Low noise level: quieter operation because the hydrodynamic bearing does not transmit structure-borne noise and the oil film acts as a noise barrier.

• Fully recyclable: low carbon footprint over the entire product lifecycle, as the entire component is manufactured without energy-intensive processes and can be fully recycled.

• Local availability of spare parts: minimizes logistics costs through segmented parts.

Your development partner for main bearings in wind turbines

Miba is your development partner for main bearings in wind turbines, offering unique testing and simulation expertise as well as application knowledge. From the initial concept phase onward, we support you with our experience to deliver robust plain bearing solutions for extreme operating conditions.

Our core competencies for your success:

• High-precision simulation: FEM, CFD, and tribological analyses predict oil film stability, thermal behavior and wear.

• Comprehensive testing expertise: Methods for optimizing development times through scaled validation. Technology demonstrated through full-scale tests.

• Application Engineering Know-how: Years of experience in wind power applications have optimized the design for functionality, ease of installation and serviceability.

Proven bearing technology for the wind energy sector

Since 2008, Miba has been developing specialized bearing solutions for wind turbines and successfully bringing them into series production. Building on nearly 100 years of experience in bearing technology, Miba is synonymous with the highest level of expertise in main bearings for wind turbines and demanding gearbox applications. Continuous investment in research and development, as well as numerous in-house patents, underscore this.

Through close collaboration with leading OEMs and gearbox manufacturers, we combine in-depth application knowledge with solid expertise in materials and design. This results in customized solutions that ensure maximum reliability, efficiency and service life.

As a globally active, family-run company, Miba combines long-term stability with technological innovation. We support our customers throughout the entire product lifecycle.