It consists of an inner ring, an outer ring, steel balls and a cage. The ratio of raceway depth to steel ball diameter has been optimized and designed. Commonly used materials are GCr15 bearing steel (containing 1.0% carbon, 1.5% chromium), with high-end models using ceramic balls (such as Si3N4) or stainless steel (AISI 440C). Surface treatment includes carburizing and quenching (hardness up to HRC60-65), anti-rust coating (such as DLC diamond-like coating), and raceway accuracy is classified according to ISO (P0/P6/P5/P4/P2).
- : Under pure radial load, the rated dynamic load C value can reach 20-200kN (such as 6208 model C=19.1kN), which is suitable for motors, pumps and other uniform-speed running equipment;
- : Can withstand small axial loads in both directions (≤10% radial load), and adapt to temperature deformation through clearance adjustment (C0/C1/C2/C3/C4);
- : The limit speed of P0 grade 6205 bearings under grease lubrication reaches 13,000 rpm, and can be increased by 30% under oil lubrication (needs to be matched with a low-resistance cage).
- : Motor rotor supports in general machinery (such as three-phase asynchronous motor end cover bearings), conveyor belt rollers;
- : CNC machine tool spindle (requires P4 level accuracy, radial runout ≤5μm), industrial robot joints;
- : In high temperature environments (-40℃~120℃), fluororubber sealing rings are optional, and in dusty scenes, a labyrinth dust cover is required (such as mine conveyors).
- General scenario: 6200 series (inner diameter 10-50mm), clearance level C3 suitable for medium loads;
- High-speed working conditions: 7000 series angular contact ball bearings (contact angle 15°/25°), with oil mist lubrication;
- Entry-level solution: NSK 6000 series (high cost performance), or domestic HRB brand (accuracy up to P6 level)
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It consists of a tapered inner ring (tapered roller assembly), a tapered outer ring and a stamped cage. The contact angle is designed to be 10°-30° (light-load type 10°-16°, heavy-duty type 25°-30°). The material is made of high-carbon chromium bearing steel (G20CrNiMo), the rollers and raceways are super-finished (surface roughness Ra≤0.2μm), and high-end models use carburizing and quenching processes (effective hardened layer depth 0.8-1.5mm).
- : Can bear radial load and one-way axial load at the same time, and the radial load-bearing capacity is 1.5-3 times that of deep groove ball bearings of the same size (such as 30207 model radial dynamic load rating C=55.8kN, axial C0a=63kN);
- : Internal clearance is eliminated through axial preloading (such as paired installation), and the rigidity is increased by 40% (suitable for spindle positioning);
- : The rolling friction coefficient is 0.0015-0.003, which is 80% lower than that of sliding bearings. However, oil lubrication is required when heating at high speeds (the limit speed is 60-70% of that of deep groove ball bearings).
- : Excavator slewing support, truck drive axle (need to withstand wheel axial thrust and road impact);
- : Lathe spindle rear support (paired installation, contact angle 25°, axial stiffness up to 15N/μm);
- : Rolling mill work roll bearings (heavy-duty 35° contact angle, impact load resistance up to 2.5 times rated value).
- Light load precision: 32000 series (single row, contact angle 15°), suitable for printing press rollers;
- Heavy-duty impact: 31300 series (reinforced rollers, crown modification design), used in mining crushers;
- Entry-level solution: NTN 30300 series (price-performance ratio is better than domestic, life coefficient Z=1.3), the axial preload needs to be controlled during installation (it is recommended to use a torque wrench to calculate based on 0.01-0.03D·N·m, D is the bearing inner diameter mm).
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