Ship propulsion shafting, steering gear equipment, deck winches, ship cranes and anchor machines are core power and operation equipment for ocean-going vessels and inland engineering ships. Shaft supports and rotary transmission parts operate under harsh working conditions: ultra-large alternating combined loads, continuous impact and vibration caused by wave undulation, splashing seawater on decks, persistent corrosion by high-concentration salt spray on sea surface, obvious temperature difference between day and night, heavy damp condensation and uninterrupted long-distance transoceanic navigation. Maintenance conditions are extremely limited during long voyages; offshore hoisting and overhaul are extremely difficult and costly. Once bearings fail, they easily lead to steering gear jamming, abnormal operation of propulsion systems and shutdown of deck lifting equipment, directly threatening navigation safety, delaying shipping schedules and incurring heavy demurrage losses. Ordinary tapered roller bearings cannot adapt to harsh marine environments with high salinity and high humidity, becoming a common pain point for ship supporting industries. Ships bear alternating wave loads continuously during navigation, and obvious axial thrust occurs during steering and lifting operations. Bidirectional alternating stress acts for a long time. Ordinary bearings have insufficient fatigue resistance and tend to form raceway indentation and rolling element surface peeling. Marine atmosphere contains high salt content; sea spray and cabin condensed water easily penetrate into bearings and rapidly induce metal pitting and rust. Salt spray together with fine sea sand continuously scours sealing structures, and simple seals quickly age and break. Seawater ingress causes emulsification and failure of lubricating grease. Large temperature difference inside and outside cabins leads to repeated vapor condensation and accelerates internal corrosion. Dry-docking overhaul cycles of vessels are long, and frequent bearing replacement greatly increases operating costs of shipping enterprises.

Focusing on transmission supporting field for marine vessels, Japan NMT specially develops seawater & salt spray resistant heavy-duty tapered roller bearings dedicated for marine shipping equipment to solve industry pain points of ordinary marine bearings such as insufficient salt spray resistance, easy seawater ingress, fatigue vulnerability under wave impact, susceptibility to rust in humid environments and insufficient service life under long voyage conditions. Taking advantage of bidirectional linear load-bearing structure of tapered rollers, combined with five core upgrades including marine-grade high-toughness corrosion-resistant bearing alloy steel, multi-layer labyrinth fully enclosed seawater-proof composite sealing, anti-corrosion super-finishing strengthening technology for raceways, seawater hydrolysis resistant long-life lubrication and precise clearance matching for marine working conditions, it fully adapts to harsh conditions of wave impact, salt spray corrosion and seawater splashing for propulsion systems, steering gears and deck machinery of all types of ships. It fundamentally solves problems including seawater rust of bearings, abrasive wear by sea sand, alternating fatigue and seal leakage, stabilizes rotation precision of ship shafting and deck equipment, and guarantees safe and stable ocean navigation.

Core Product Advantages

1. Bidirectional ultra-large combined load bearing withstands wave impact and operational axial thrust: Adopting tapered roller linear contact structure, it bears high-strength radial loads and persistent axial thrust simultaneously with uniform load distribution in contact zones. It buffers continuous impact brought by wave undulation during navigation, balances axial force generated by steering gear turning and deck lifting operations, restrains excessive unilateral raceway wear and stably controls axial play of shaft systems.

2. Marine-grade corrosion-resistant high-toughness bearing steel matrix resists seawater pitting and long-term fatigue: Selected high-purity corrosion-resistant bearing alloy steel specially for marine equipment undergoes quenching & tempering and surface anti-corrosion strengthening treatment to optimize metallographic structure, balancing toughness, surface hardness and seawater corrosion resistance. It withstands long-term alternating impact loads during navigation and lowers risks of raceway fatigue damage, rolling element peeling and pitting corrosion in marine environments.

3. Multi-layer labyrinth fully enclosed seawater-proof composite sealing blocks ingress of seawater, salt spray and sea sand: Equipped with exclusive thickened seawater-resistant wear lip & multi-labyrinth sealing structure for marine conditions. It resists seawater scouring and salt spray aging, not easy to be worn and torn by sea sand. It intercepts splashing seawater, salt spray moisture and fine marine sand layer by layer, prevents grease emulsification and deterioration caused by seawater penetration and avoids abrasive wear induced by hard sea sand particles.

4. Anti-corrosion super-finished strengthening technology for raceways ensures stable operation and slows corrosion loss: Micron-level super-finishing grinding together with anti-corrosion surface treatment is applied on contact surfaces of raceways and rollers to optimize contact profile, improve protective oil film performance in humid marine environments, reduce frictional temperature rise under continuous vibration operation, slow precision attenuation during long voyages and cut equipment vibration and abnormal noise.

5. Marine customized clearance & seawater hydrolysis resistant long-life lubrication system: Internal clearance is precisely matched according to different load characteristics of propulsion shafting, steering gears and deck machinery to avoid seizure caused by condensation at low temperature and thermal expansion seizure under continuous heavy loads. Matched with special lubrication formula resisting seawater hydrolysis and salt pollution, it adapts to variable temperature and humidity environments inside and outside cabins and extends lubrication maintenance intervals between ship dry-docking cycles.

Application Scenarios

Main propulsion shaft support bearings for ships, rotary mechanism bearings for steering gears, transmission bearings for anchor machines and winches, support bearings for deck cranes, operating mechanism bearings for dredgers and engineering vessels, heavy-duty transmission supporting positions for power systems and deck equipment of all ocean-going cargo ships, container ships and inland waterway vessels.

Precision Quality Assurance

NMT tapered roller bearings for marine shipping are manufactured strictly in accordance with Japanese marine equipment component manufacturing standards. Selected special bearing steel with high toughness, impact resistance and seawater & salt spray resistance undergoes alternating impact durability test, long-term neutral salt spray anti-corrosion test, seawater spray sealing test, high-low temperature humid cycle aging test and continuous heavy-load fatigue test. The products feature excellent bidirectional load capacity, outstanding stability against wave impact and durable reliable seawater-resistant sealing performance, fully adapting to long-voyage conditions with heavy salt spray, high humidity and continuous vibration for ocean-going and inland ships.

Product Range

Heavy-duty tapered roller bearings for ship propulsion shafting, long-life salt-spray resistant bearings for steering gears, wear-resistant bearings for deck winches and cranes, seawater-resistant bearings for engineering dredgers, customized large-size non-standard tapered roller bearings for large marine equipment.

Brand Strength

Japan NMT focuses on R&D and manufacturing of bearings for heavy-duty marine vessels under working conditions of ultra-large alternating combined loads, continuous wave impact, splashing seawater, marine salt spray corrosion, damp condensation in cabins and long-cycle voyages, specializing in core technologies of bidirectional load balance, seawater anti-corrosion protection, fully enclosed erosion-resistant sealing and vibration fatigue wear prevention. With Japanese marine-grade corrosion-resistant steel heat treatment technology, exclusive seawater-proof sealing technology for marine equipment and strict marine condition simulation durability testing system, it accurately solves industry pain points of marine bearings such as seawater pitting corrosion, abrasive wear failure by sea sand, alternating fatigue spalling, seal leakage and difficulties in offshore maintenance, supplying high-load, impact-resistant and seawater & salt spray resistant long-life core transmission bearing components for global manufacturers of ship power and deck machinery.