Tapered roller bearing No.2612

axialstainless steelfor mining and the metallurgical industry

Overview
NSK has developed reconditionable large-size tapered roller bearings (TRBs) for heavy-duty mining use. The bearings combine high load capacity and a separable structure to enable on-site reconditioning and reuse, reducing maintenance cycles and lifecycle CO₂ emissions.

Key points

• Intended for dump truck wheels, crushers, grinding rollers and other heavy mining equipment
• Separable design allows disassembly and reconditioning to lower replacement frequency
• Up to 2× life versus conventional TRBs enabled by NSK’s Micro-UT™ life prediction (patent pending)
• Detachable inner-ring small rib (removable bolts) for detailed internal inspection

Development background
Mining machines operate continuously at low speeds under heavy loads and strong vibration. Conventional large TRBs are often non-separable and discarded at maintenance, increasing waste and lifecycle cost. These reconditionable TRBs were developed to extend service life while enabling repeated inspections and repairs on site.

Features
NSK technologies integrate three principal features: extended service life (high load capacity), a separable inner-ring rib for internal inspection, and a staked-bolt design preventing bolt loosening under vibration.

1. Long life (High load capacity) for long-term use
Micro-UT™ ultrasonic material testing provides highly accurate fatigue-life prediction based on non-metallic inclusion statistics, enabling a design with higher dynamic load rating and up to twice the life of conventional products.

2. Separable structure for in-depth inspections
The inner-ring small rib is removable via bolts, allowing rollers, cage and inner ring to be separated for detailed inspections and maintenance at site, facilitating reconditioning and reuse.

3. Anti-vibration staked-bolt design
Bolt holes for the separable rib are staked/pressed to prevent bolt loosening or displacement in high-vibration mining environments, improving operational reliability.

Product benefits
Reconditionable TRBs reduce replacement counts and maintenance costs and contribute to lower CO₂ emissions over equipment lifecycles. Example reductions per maintenance cycle: dump truck bearings 8→4; crusher bearings 12→6. A CFP example estimates ~3,102 kg-CO₂ reduction for dump truck wheels in the described lifecycle scenario (usage 60,000 hours; assessment referenced by NSK).

Applications and commercialization
Target applications include dump truck wheels and grinding rollers (vertical grinding mill) plus crushers. NSK will provide samples to equipment manufacturers and aims to expand to cement and related industries, targeting annual sales of 2 billion yen by 2030.

Notes
Micro-UT™ is NSK’s ultrasonic material testing that quantifies non-metallic inclusions in bearing steel for accurate fatigue-life prediction (patent pending). Design details and securing methods are subject to pending patents.

Technical specifications

• Product type: Reconditionable large-size tapered roller bearing (TRB)
• Expected life: up to 2× conventional TRBs (based on Micro-UT™ prediction)
• High load capacity design (improved basic dynamic load rating)
• Separable inner-ring small rib (removable bolts) enabling full internal inspection and disassembly
• Staked/pressed-bolt design to prevent loosening under vibration
• Testing / life prediction: Micro-UT™ ultrasonic material testing (patent pending)
• Intended applications: dump truck wheels, crushers, grinding rollers (vertical grinding mill), other heavy mining equipment
• Reconditioning benefit: enables repair and reuse (example replacements reduced: dump truck 8→4; crusher 12→6)
• Estimated CO₂ reduction example: ~3,102 kg-CO₂ for dump truck wheels in the illustrated CFP scenario
• Commercial plans: sample provision to manufacturers; target sales 2 billion yen by 2030