Spherical plain bearings are sliding hinge bearings composed of an inner spherical ring and an outer spherical ring with circular arc sliding fit between spherical surfaces. They support multi-angle deflection, swinging motion and combined radial & axial displacement. Outstanding advantages include large-angle self-alignment, strong impact load resistance and remarkable durability under low-speed swinging conditions. Different from point/line contact of rolling bearings, the overall spherical surface contact disperses impact force, perfectly matching reciprocating swing, eccentric load and impact conditions such as construction machinery hinge points, hydraulic cylinder trunnions, connecting rod hinges and lifting lug joints.

Main product categories cover four core types: GE standard steel-on-steel spherical plain bearings, GEG self-lubricating bronze liner bearings, GX thrust spherical plain bearings, SI/SA rod end spherical bearings. Three structural types: open non-sealed, double-sided rubber dust-proof sealed and metal dust cover protection. Steel-on-steel bearings suit regular grease replenishment maintenance, while self-lubricating models with built-in solid lubricating film operate for a long time without grease supply in dusty and muddy environments. Widely applied to boom hinges of excavators, lift cylinders of loaders, crane lifting lugs, hinged supports of dump trucks, metallurgical connecting rods and hinge fulcrums of agricultural machinery.

Main model classification: GE general radial spherical plain bearings, GEG maintenance-free self-lubricating spherical plain bearings, GX thrust spherical plain bearings, SI female thread rod end bearings, SA male thread rod end bearings; Precision grade: P0 heavy-duty industrial grade; Lubrication types: oil-grease lubrication for steel-steel friction, bronze-backed solid self-lubrication; Sealing options: open type, double-sided rubber seal, stamped steel dust cover; Motion adaptation: reciprocating swing, angular deflection, static hinge positioning.

Performance comparison: Compared with spherical roller bearings, it allows larger swing angles and bears strong instantaneous impact loads, designed for low-speed swing rather than continuous high-speed rotation. Compared with housed insert bearings, its load capacity increases several times with powerful anti-extrusion deformation performance for heavy-load hinges instead of roller rotation. Compared with tapered roller bearings, it adapts to severe shaft deflection without jamming, while the disadvantage is obvious heat generation under high-speed rotation, prohibiting continuous high-speed operation. Positioned as core hinge components for low-speed heavy-load swing applications.

Construction machinery operates in mines, construction sites and muck yards year-round, enduring continuous rock impact, mud immersion, sand and dust intrusion, high-frequency reciprocating swing of oil cylinders and alternating impact from vehicle bumping. Inferior spherical plain bearings suffer from insufficient quenching hardness on spherical surfaces, leading to rapid indentation under impact load. Out-of-control fitting clearance causes excessive play at hinge points, shaking booms and poor operation precision. Lack of effective sealing allows sediment to abrade spherical fitting surfaces directly, leading to rapid grease failure and dry friction, triggering abnormal hinge noise, jamming and spherical seizure. In severe cases, cylinder trunnion deformation and hinge tear of mechanical booms occur, resulting in construction machinery shutdown and high emergency repair costs.

NMT spherical plain bearings fully cover GE, GEG, GX, SI and SA series with sufficient stock for steel-on-steel greased models for construction machinery, maintenance-free self-lubricating models for mines and rod end spherical bearings. Inner and outer rings are made of high-carbon carburized bearing steel with integral quenching and spherical superfinishing honing for uniform spherical contour, smooth swinging without jamming and maximum 30° multi-angle deflection to adapt to axis offset caused by cylinder swing. Steel-on-steel models are equipped with annular oil grooves and grease nipples for even grease coverage on friction spherical surfaces to buffer impact for a long time. GEG self-lubricating bearings adopt sintered bronze alloy and molybdenum disulfide solid lubricating layer on inner fitting surfaces, maintaining smooth sliding under oil cutoff, water immersion and dusty conditions to eliminate dry friction seizure.

Full-size models are equipped with thickened rubber sealing rings or steel dust covers to block muck, mud and gravel from entering spherical friction pairs and extend spherical wear life. Overall dimensions comply with national standard specifications for direct replacement of old and new oil cylinders and hinged supports without reaming modification. Finished bearings pass spherical fitting inspection, impact load durability test and dust-proof sealing spray test to eliminate defective products with spherical damage, excessive clearance and lubricating layer peeling.

Construction machinery and hydraulic equipment are upgraded toward large-tonnage heavy load, all-weather field operation and long-cycle maintenance-free operation. Low-grade spherical plain bearings feature thin wear-resistant spherical layers, simple sealing and unreasonable lubrication structure, resulting in loose hinge play, abnormal noise and seizure after short-term field operation and high equipment failure rate. The market is in urgent need of heavy-duty spherical plain bearings with high impact-resistant spherical surfaces, strong dust-proof sealing and optional dual-lubrication structures.

Relying on three core technologies: high-precision spherical honing forming, composite dust-proof sealing structure and dual lubrication process (grease lubrication + solid self-lubrication), NMT solves four major defects of ordinary spherical plain bearings: swing jamming, impact indentation, sediment abrasion and lubrication failure. It ensures long-term high-intensity operation of hinge points for excavation, loading and lifting equipment, reduces emergency on-site maintenance frequency and cuts spare parts costs for construction machinery maintenance.

Core Product Advantages

Spherical surface contact structure evenly disperses impact load, resisting indentation and depression under heavy extrusion for rigid and stable hinge structure.

Large-angle adaptive deflection adapts to axis offset from reciprocating cylinder swing to avoid bearing jamming and over-limiting stress.

Optional dual lubrication solutions: greased type for heavy-load regular maintenance conditions, bronze-lined self-lubricating type for low-maintenance harsh field conditions.

Multi-layer sealing protection with optional rubber seal and steel dust cover delivers powerful mud and sand blocking performance to protect spherical friction surfaces.

Integrally quenched high-strength bearing steel resists deformation, rolling and rock impact for harsh impact environments of mines and construction sites.

Complete thread specifications for rod end bearings enable easy connecting rod and pull rod assembly with high thread strength against vibration loosening and slipping.

Standard universal overall dimensions support direct replacement for construction machinery oil cylinders and hinged supports to save on-site maintenance time.

Special design for low-speed swing avoids high-speed heat generation defects and achieves far longer service life than rolling bearings under continuous reciprocating swing conditions.

Typical Application Scenarios

Construction machinery hinges: Bucket arm, boom and bucket hinge bearings for excavators, lift cylinder hinges for loaders, spherical plain bearings for crane lifting points; Hydraulic cylinder accessories: Trunnion bearings for dump truck cylinders, telescopic cylinder hinges for cranes, hinge fulcrums for metallurgical hydraulic cylinders; Connecting rod transmission parts: Heavy connecting rod hinges, swing fulcrums of agricultural machinery, movable supports for mine conveying equipment; General machinery rod end joints: Hydraulic pull rods, shock absorption hinges, mold movable fulcrums, lifting ring spherical joints.

Quality Assurance

NMT spherical plain bearings adopt deep quenching of carburized bearing steel with qualified spherical surface hardness for excellent wear resistance and anti-fatigue spalling performance. Grease-lubricated models are compatible with extreme pressure lithium grease for construction machinery, while self-lubricating models adapt to dry friction and water immersion. Operating temperature ranges from -35℃ to 130℃, adapting to harsh conditions including severe cold construction sites in winter, high-temperature open-air operation in summer, mud immersion, rock impact and 24-hour intermittent heavy-load swing. Threads of rod end bearings are strengthened by rolling for compact thread profile to prevent thread slipping and fracture under vibration and heavy load.

Product Range

GE radial steel-on-steel lubricated spherical plain bearing series, GEG bronze-backed maintenance-free self-lubricating spherical plain bearing series, GX thrust spherical plain bearing series, SI female thread rod end spherical bearings, SA male thread rod end spherical bearings; Lubrication modes: grease lubrication, solid self-lubrication; Sealing forms: open type, double-sided rubber seal, steel dust cover; Applicable conditions: low-speed reciprocating swing, heavy impact load, hinge points with dusty and humid field environment.

Brand Strength

NMT Japan focuses on R&D and manufacturing of heavy-duty hinged sliding bearings, solving typical drawbacks of conventional spherical plain bearings such as easy spherical indentation, water and sand ingress through seals, swing jamming and short lubrication service life. Benefiting from precision spherical honing, composite dust-proof sealing and dual-lubrication system, NMT develops heavy-duty spherical plain bearings specially for construction machinery oil cylinders. We supply products to construction machinery OEMs, cylinder manufacturers, mine equipment repair factories, construction machinery parts distributors and modification factories to enhance the stability of equipment hinge points, extend the replacement cycle of hinge bearings and reduce comprehensive operation and maintenance costs of engineering equipment.