Ship cranes, windlasses, mooring winches and towing machines are core lifting and mooring equipment for ocean-going and inland vessels. Slewing and luffing supports of ship cranes, main shafts of windlasses and drum supports of winches operate under harsh working conditions: ultra-large continuous combined impact loads, erosion by marine salt-laden sea wind, continuous scouring by splashing seawater, instantaneous impact during cargo handling, drastic open-air temperature variation on decks, alternating wet and dry cycles inside and outside cabins and standby operation throughout ocean voyages. Ship navigation has extremely low fault tolerance. Far away from ports at sea, bearing failure will disable ship cranes for cargo loading/unloading, and malfunction of windlasses and winches will directly threaten anchoring and mooring safety. Offshore repair is extremely difficult and spare parts supply takes a long time, easily leading to shipping schedule delays, heavy demurrage charges and even potential navigation hazards. Ordinary tapered roller bearings cannot adapt to harsh marine environments with heavy salt mist and splashing seawater on decks, becoming a common pain point for marine equipment manufacturers and shipping operation teams. Cargo hoisting and chain hauling continuously generate fluctuating loads and axial thrust. Frequent alternating loads arise from swinging heavy goods and anchor chain impacts. Ordinary bearings lack sufficient impact toughness and tend to form raceway indentation and rolling element surface peeling under long-term cyclic loads, triggering mechanism shaking and operation jamming. Marine air contains abundant chloride ions. Salt-laden vapor carried by splashes and rainwater easily penetrates into bearings along shafts, emulsifies grease and induces severe electrochemical corrosion. Deck dust mixed with sea salt particles abrades simple seals, and continuous ingress of seawater vapor accelerates corrosion and wear of internal components. Alternating sunshine, rain and temperature changes continuously harden sealing materials and cause loss of elasticity. Vessels only undergo docking maintenance periodically, and large-scale disassembly cannot be carried out at sea. Frequent bearing replacement continuously increases shipping costs and navigation risks.

Focusing on transmission supporting field for marine lifting and mooring equipment, Japan NMT specially develops salt-spray waterproof impact heavy-duty tapered roller bearings dedicated for ship cranes, windlasses and winches for ocean vessels to solve industry pain points of ordinary marine bearings such as insufficient seawater corrosion resistance, easy ingress of splash vapor, fatigue spalling induced by lifting impact, susceptibility to rust under alternating wet and dry conditions and limited service life during long ocean voyages. Taking advantage of bidirectional linear load-bearing structure of tapered rollers, combined with five core upgrades including chloride-resistant high-toughness bearing alloy steel, multi-layer labyrinth salt mist splash-proof waterproof composite sealing, deep-hardening super-finishing strengthening technology for raceways, seawater hydrolysis-resistant long-life lubrication and precise clearance matching for fluctuating marine lifting loads, it fully adapts to harsh deck conditions with salt mist erosion, splash scouring and alternating wide-range temperature. It fundamentally solves problems including seawater-induced rust of bearings, abrasive wear by vapor, impact fatigue spalling and grease emulsification, stabilizes rotation precision of slewing mechanisms and drums and guarantees long-term reliable operation of marine lifting, anchoring and mooring equipment on ocean-going vessels.

Core Product Advantages

1. Bidirectional ultra-large combined impact load bearing withstands lifting impact and dynamic axial thrust: Adopting tapered roller linear contact structure, it bears high-strength radial heavy loads and continuous axial thrust simultaneously with uniform load distribution in contact zones. It effectively buffers alternating impact generated during cargo handling and anchor chain retrieval, balances eccentric loads during operation of ship cranes and winches, restrains local overload wear on unilateral raceways and stably controls axial play of shaft systems to ensure smooth operation of lifting and mooring mechanisms and reduce jamming and shutdown risks.

2. Salt-fog resistant high-toughness bearing steel matrix delivers long-term fatigue and corrosion resistance under marine deck conditions: Selected high-purity chloride-resistant bearing alloy steel specially for heavy marine lifting equipment undergoes multiple quenching & tempering heat treatments to optimize metallographic structure under humid salt-mist marine environments, greatly improve resistance to seawater pitting corrosion while maintaining excellent impact toughness. It withstands long-term alternating lifting loads, delays raceway fatigue damage and surface peeling of rolling elements, and lowers risks of failure caused by persistent seawater salt mist corrosion.

3. Multi-layer labyrinth salt mist splash-proof waterproof composite sealing blocks continuous ingress of salt mist vapor and seawater: Equipped with exclusive thickened seawater-resistant wear-resistant seal lip & multi-labyrinth protective structure for deck conditions. It resists continuous scouring by splashes, maintains elasticity under alternating high and low temperatures, intercepts salt-laden vapor, splashing seawater and sea salt dust layer by layer, prevents seawater media from entering housings and contaminating grease, and avoids persistent corrosion and particle abrasion induced by seawater.

4. Deep-hardening super-finishing grinding technology for raceways reduces frictional temperature rise and suppresses mechanism vibration: Deep hardening treatment plus micron-level super-finishing grinding is applied on contact surfaces of raceways and rollers to optimize contact profile, improve oil film stability under alternating marine wet and dry conditions, reduce heat accumulation under intermittent impact loads, slow precision attenuation after years of ocean navigation and lower vibration and abnormal noise of ship cranes and windlasses.

5. Customized clearance for marine lifting equipment & seawater hydrolysis-resistant long-life lubrication system: Internal clearance is precisely matched according to different operating temperature and load of crane slewing supports, windlass main shafts and winch drums to avoid seizure under low temperature and thermal expansion seizure under sustained high temperature. Matched with special lubrication formula resistant to seawater and salt mist hydrolysis, it adapts to changeable open-air wet and dry environments on decks and extends on-vessel lubrication maintenance intervals during voyage.

Application Scenarios

Slewing and luffing mechanism support bearings for ship cranes, main shaft and drum bearings for windlasses and winches, transmission bearings for towing machines, drive bearings for hatch covers, heavy-duty transmission supporting positions of deck lifting and mooring equipment on all ocean-going cargo ships, container ships, bulk carriers and engineering vessels.

Precision Quality Assurance

NMT tapered roller bearings for marine and port lifting machinery are manufactured strictly in accordance with Japanese heavy marine equipment component manufacturing standards. Selected special bearing steel with high toughness, seawater salt spray corrosion resistance and water abrasion resistance undergoes alternating impact durability test, long-duration neutral salt spray corrosion test, splash spraying sealing durability test, high-low temperature wet-dry cycle aging test and long-duration fluctuating load operation test. The products feature powerful bidirectional load capacity, outstanding impact resistance and robust reliable seawater-proof sealing performance, fully adapting to 24-hour ocean voyage conditions with floating salt mist and splashing seawater on ship decks.

Product Range

Heavy-duty impact-resistant tapered roller bearings for ship cranes, long-life salt mist & waterproof bearings for windlasses and winches, low-vibration transmission bearings for towing machines, wear-resistant drive bearings for hatch covers, customized large-size non-standard tapered roller bearings for complete large marine lifting equipment.

Brand Strength

Japan NMT focuses on R&D and manufacturing of bearings for heavy marine lifting and mooring equipment under working conditions of dynamic combined impact loads, instantaneous cargo lifting impact, seawater & salt mist corrosion, continuous splash scouring, wide open-air temperature range on decks and long-term ocean navigation, specializing in core technologies of bidirectional load balance optimization, marine anti-corrosion rust prevention, multi-layer salt mist waterproof sealing protection and alternating fatigue wear prevention. With Japanese heat treatment technology for marine-grade high-toughness chloride-resistant steel, exclusive seawater-proof sealing technology for deck lifting machinery and strict marine salt mist condition simulation durability testing system, it accurately solves industry pain points of marine bearings such as seawater rust, abrasive wear failure by vapor, impact fatigue spalling, difficult offshore repair and shipping schedule delays, supplying high-load, impact-resistant, salt mist & waterproof long-life core transmission bearing components for global marine machinery manufacturers.