1.Why one ring decides the uptime of a whole turbine

GWEC expects annual offshore wind installations to double in 2026, with roughly 129 GW of new offshore capacity added between 2026 and 2030. Bigger turbines mean heavier rotors, longer blades and higher tilting moments at the top of the tower — all of it passing through one component: the slewing bearing.

A wind turbine uses very few of them. But when a slewing ring fails, the machine stops. That is why specification decisions made at the quotation stage matter far more than the price difference between two suppliers.

Position 1: the yaw bearing, between nacelle and tower

The yaw bearing sits between the nacelle bedplate and the tower top flange. It is a large-diameter, flat external gear slewing ring.

It does two jobs at once. It carries the full weight of nacelle, hub and blades — often well over a hundred tonnes — and it lets the whole nacelle rotate slowly around the tower axis. The rotation comes from several vertical yaw drives whose pinions mesh with the gear teeth on the outer ring, nudging the nacelle into the wind.

Position 2: the pitch bearing, at each blade root

The pitch bearing hides inside the hub, mounted between the hub casting and the root of each blade — three blades, three bearings. It lets each blade rotate about its own axis to change the angle of attack: feather in high wind, open up in low wind.

Pitch motion is frequent, the angles are small, and the accuracy requirement is high. On a wind turbine slewing bearing, starting torque and smooth rotation matter far more than the ability to simply turn.

2.What wind duty does to a slewing ring

It never stops loading. The bearing carries the entire rotor mass plus constantly changing aerodynamic loads, including tilting moments that reverse direction as the wind shifts.

It moves slowly but often. Yaw and pitch are low-speed, intermittent motions. The hardest moment is not continuous running — it is breaking away from standstill after a long dwell.

It has to last 20 years. OEMs typically specify a 20-year design life, which means raceway fatigue, gear tooth wear and seal ageing all have to be engineered in, not discovered later.

It sits in weather, not in a workshop. Temperature swings, humidity, salt spray and dust attack the seal first. Once the seal fails and grease escapes, raceway damage follows quickly.

3.How Xuzhou Wanda Slewing Bearing builds for this duty

a. Fifteen years on one product line. Founded in 2011, Xuzhou Wanda Slewing Bearing Co., Ltd. operates a site of about 7.9 hectares with 60,000 m² of buildings and a RMB 250 million factory investment. Annual capacity reaches 160,000+ slewing bearings and 60,000+ slewing drives.

b. The three core processes are in-house. Production runs through 15 process steps with full equipment coverage. Raceway heat treatment, gear heat treatment and raceway precision machining are handled with dedicated heat-treatment equipment, high-speed gear hobbing machines and precision finishing equipment — the variables that decide gear noise and service life on an external gear slewing ring.

c. Inspection is 100%, not sampled. From incoming raw material to finished goods, every unit passes self-check, cross-check, patrol inspection and a 100% final inspection. Material is 50Mn or 42CrMo, verified by spectrometer; metallography, case depth and hardness are checked on sectioned samples.

d. It is tested, not just calculated. A T850 slewing bearing type-test rig applies axial load, radial load and tilting moment to simulate real duty and run life tests. The plant also runs slewing drive life and impact rigs plus a solar reducer test bench.

e. Marine and heavy-equipment approvals are already in place. The company holds CCS type approval — the only slewing bearing manufacturer in Xuzhou to do so — and can also supply ABS and NK certified products. Quality management is certified to ISO9001, ISO14001 and ISO45001, alongside national High-Tech Enterprise status and Jiangsu provincial recognition as a Specialized and Sophisticated SME, a Gazelle Enterprise and a Green Factory.

f. Export customers have already stress-tested the process. International business accounts for more than 45% of sales, with products shipped to over 70 countries; Europe and the Americas make up 67% of exports. Long-term customers include XCMG, Sunward, Terex (USA) and CSSC Luzhou — buyers whose requirements push both hardware and process discipline.

g. R&D is a standing function. The company runs a Jiangsu Provincial Engineering Technology Research Center and a provincial postdoctoral innovation base, working with China University of Mining and Technology and Northwestern Polytechnical University on gear finishing, raceway heat treatment and automated production lines.

4.FAQ

Can a yaw bearing be used as a pitch bearing? No. Load direction, motion frequency and mounting interface all differ; substituting one for the other shortens life.

External gear or internal gear? It depends on the drivetrain layout. Yaw systems usually use an external gear; pitch bearings come in both, decided by hub space and drive position.

What do you need for a quotation? Bearing type, outer diameter and mounting holes, gear data (module and tooth count), load case or duty description, quantity and delivery target. The more complete the data, the faster and more accurate the quote.

Talk to the manufacturer

Wind reliability starts at one slewing bearing. Choose the right structure, control the gear process, and hold the inspection — then the next twenty years of O&M stay simple.

If you are sourcing a wind turbine slewing bearing, or need a large diameter slewing bearing for cranes, excavators, marine equipment or solar trackers, contact Xuzhou Wanda Slewing Bearing Co., Ltd. and we will work from your actual duty conditions.

If you have any requirement for slewing bearings, please contact Xuzhou Wanda Slewing Bearing Co., Ltd.