Tapered roller bearing No.2610

axialstainless steelfor gearboxes

Overview
A leading European manufacturer of wind turbines will use NSK high-load-capacity tapered roller bearings in the gearboxes of its 15 MW class offshore wind turbines. Mass production and delivery of the newly developed high-performance bearings is due to start imminently.

Key benefits

• Approximately 25% increase in load capacity compared with the conventional product through optimisation of the roller crowning shape (a slight arc shape that avoids stress concentration at the roller ends).
• More than double the service life of the conventional product.
• Lighter weight enabling reduction of construction and maintenance costs for large wind turbines; weight reduction of more than 30% under the same usage conditions versus conventional bearings.
• Eliminates need for upsizing bearings in many high-load applications due to more uniform contact pressure.
• Designed and specified for gearboxes of 15 MW class offshore wind turbines; mass production imminent.

Technical details

• Optimised roller crowning shape to avoid stress concentration at roller ends and to equalise contact surface pressure between rollers and inner and outer rings.
• NSK used numerical simulation expertise to derive the roller crown shape and to equalise contact pressure, preventing excessive surface pressure at roller ends even under high loads.
• New high-productivity processing technique developed for manufacturing the intricate crowning shape.
• Outcomes: ~25% higher load capacity, >2x service life, >30% weight reduction under comparable conditions.

Image captions

• 1) The gearbox of a wind turbine and the NSK high-load tapered roller bearing (Inset)
• 2) NSK’s optimised roller crowning shape
• 3) The NSK bearings offer uniform contact pressure at the roller ends (below, bottom)

Technical specifications

• Application: Gearboxes for 15 MW class offshore wind turbines
• Load capacity: ~25% increase vs conventional product
• Service life: More than double vs conventional product
• Weight: >30% reduction under same usage conditions compared with conventional bearings
• Design feature: Optimised roller crowning shape (slight arc) to avoid end stress concentration and to equalise contact pressure
• Engineering: Numerical simulation used to derive shape and equalise contact pressure between rollers and rings
• Manufacturing: New high-productivity processing technique for roller crowning
• Production status: Mass production and delivery due to start imminently