What type of bearings are used in wind turbines?

Update time : 2026-01-30 09:24:03

What are the key bearings hidden inside a wind turbine?

When a wind turbine slowly rotates hundreds of meters in the air, it appears elegant and quiet.

But inside, every rotation, every yaw, and every gust of strong wind tests the limits of the bearings.

It's no exaggeration to say that:

Bearings are one of the most critical and "uncompromising" components in a wind turbine.

So the question arises: What types of bearings are used in wind turbines? And why must they be selected in this way?

First, let's understand: How demanding are wind turbine bearings?

Before delving into specific bearing types, let's recognize one fact: Wind power operation is on a completely different level of difficulty than ordinary industrial equipment.

Wind turbine bearings typically face the following challenges:

1.Extremely large size (often 1-3 meters in diameter)

2.Extremely low speed + extremely high load

3.Coexistence of alternating and impact loads

4.Continuous operation for 20-25 years

5.Almost impossible to maintain after installation

6.Extreme environments: low temperature, high humidity, salt spray, dust storms

This means: Ordinary bearings that simply "just need to rotate" won't last more than a few years in wind power.

II. Key Components of Wind Turbines & Corresponding Bearing Types

A wind turbine doesn't use just one type of bearing; multiple bearings work together. Let's look at them by component.

III. Main Shaft Bearing

Common Types

1.Spherical Roller Bearing

2.Tapered Roller Bearing (used in double rows or pairs)

Why must the main shaft use "them"?

The main shaft bearing bears the load of:

1.The entire weight of the impeller

2.The enormous radial force caused by wind load

3.The simultaneous axial force

4.Shaft deflection and misalignment

This is precisely where self-aligning roller bearings excel:

1.Strong self-aligning capability

2.Excellent shock resistance

3.Particularly suitable for low-speed, heavy-load applications

In some direct-drive or semi-direct-drive structures,

double-row tapered roller bearings are also used to provide higher axial rigidity.

IV. Gearbox Bearings

If the main shaft bearing is about "resistance,"

then gearbox bearings test precision + lifespan + stability.

Common Bearing Types

1.Cylindrical Roller Bearing

2.Tapered Roller Bearing

3.Deep Groove Ball Bearing (Auxiliary Position)

Why are gearbox bearings most prone to problems?

Because they face:

1.High contact stress

2.Micropitting

3.Off-center loading

4.Vibration

5.Complex lubrication conditions

Especially for high-speed bearings, failure results in extremely high repair costs, often meaning the entire turbine unit will be shut down.

This is why wind turbine gearbox bearings have much higher requirements in terms of materials, heat treatment, and internal geometry design than ordinary industrial bearings.

V. Yaw Bearing

Common Types

1.Four-point contact ball bearing

2.Crossed roller bearing

3.Large slewing bearing

What is its task?

Yaw bearings are responsible for:

1.Maintaining the rotation of the entire nacelle with the wind direction

2.Bearing the weight of the entire turbine

3.Resisting the overturning moment generated by wind loads

The defining characteristic is: "Large"

1.Large diameter

2.High torque

3.Low speed, intermittent motion

These bearings may seem to rotate little, but once they jam or wear, the consequences are extremely serious.

VI. Pitch Bearings

Common Types

1.Four-point contact ball bearings

2.Double-row ball slewing bearings

Why are pitch bearings so critical?

They directly control:

1.Blade angle

2.Power generation

3.Overspeed protection

If a pitch bearing fails,

the wind turbine either won't generate electricity or will be forced to shut down.

Therefore, it must not only bear the load but also:

1.Low starting resistance

2.High positioning accuracy

3.Strong fatigue resistance

VII. Generator Bearings

Common Types

1.Deep groove ball bearings

2.Cylindrical roller bearings (insulated type)

Special Concern: Electrolytic corrosion

In generators, bearings are not only mechanical components,

but also face a "hidden killer"—current passing through the bearings.

This is why:

1.Insulated bearings

2.Hybrid ceramic bearings

are becoming increasingly common in wind turbines.

VIII. Why do wind turbine bearings "look similar but have such different prices"?

The key isn't the "type," but the details:

1.Material purity

2.Racetrack geometry modification

3.Surface roughness

4.Heat treatment depth

5.Coating and anti-corrosion design

6.Lubrication scheme matching

Even though they're both called "self-aligning roller bearings,"
the lifespan design of wind turbine-grade and ordinary industrial-grade bearings can differ by an order of magnitude.

IX. Trends: Where are wind turbine bearings headed in the future?

1.Larger size

2.Higher load density

3.Longer maintenance-free cycle

4.More intelligent (condition monitoring)

5.Stronger resistance to electrolytic corrosion and micropitting corrosion

As wind turbine power increases from 3MW → 10MW → 15MW,
bearings are no longer just "standard parts," but part of a system-level engineering project.

X. Conclusion: Wind turbines can operate for 20 years, and it's not just about the wind.

Many people only see the blades and towers,
but ignore the bearings hidden inside, silently bearing everything.

They don't generate electricity or make noise,
but once they fail, the entire wind turbine stops.

So, the next time you see a wind turbine spinning in the distance,

remember this:

What truly turns wind into electricity is not just the wind itself, but also the bearings.

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