1. Core Advantages
Ultra-Compact Radial Dimension: The rolling elements adopt slender needles (aspect ratio usually ＞3), enabling high load capacity without large-diameter rolling elements. The radial structural dimension is over 30% smaller than that of
Ball Bearings of the same specification, making it suitable for precision equipment with limited space.
High Load-Carrying Capacity: The large contact area between needles and raceways ensures uniform load distribution per unit area. The radial rated dynamic load is much higher than that of ball bearings and ordinary roller bearings of the same volume, adapting to heavy-load working conditions.
Dual Advantages of Precision and Rigidity: Needles undergo precision
Grinding, and combined with high-precision raceway design, the rotational accuracy can reach above P5 class. Meanwhile, the compact structure provides excellent radial rigidity, reducing operational deformation.
Balanced Cost and Energy Efficiency: Compared with other bearings of the same load-carrying capacity, it uses less material and has lower manufacturing costs. With a small rolling friction coefficient (usually ＜0.0015), it can reduce equipment energy consumption.
2. Key Features
Structural Form: Composed of outer ring, inner ring (or without inner ring, directly matching with journal), needles, cage (or full-complement structure). Some models are equipped with seals (e.g., double-sided rubber seals).
Rolling Element Characteristics: Needles typically have a diameter of 2-10mm and length of 5-50mm, with surface roughness Ra ≤ 0.1μm and hardness reaching HRC 60-65, ensuring wear resistance and impact resistance.
Adaptation Flexibility: Classified into types with inner ring, without inner ring, drawn cup, solid outer ring, etc. Models without inner ring can directly use the journal as the raceway, further saving space.
Sealing and Lubrication: Some models integrate rubber seals or metal dust covers to effectively block impurities; full-complement types are usually pre-filled with grease, extending maintenance intervals.
3. Core Manufacturing Processes
Needle Manufacturing: High-purity
Bearing steel (SUJ2) undergoes cold heading forming → heat treatment (quenching + low-temperature tempering) → precision grinding → surface polishing to ensure dimensional accuracy and mechanical properties.
Raceway Processing: Outer/inner rings go through
Forging blanking →
Turning rough
Machining → heat treatment (integral quenching) → grinding (inner raceway, outer circle) → superfinishing, with raceway roundness error ≤ 0.002mm.
Assembly Process: Cage-type adopts assembly line of "needle sorting → automatic needle loading → clearance inspection"; full-complement type requires special tooling for orderly needle arrangement, followed by rotational flexibility testing after assembly.
Quality Inspection: Covers dimensional accuracy (tested with micrometer, projector), hardness testing (Rockwell hardness tester), rotational accuracy (bearing rotational accuracy tester), and life testing (simulated working condition tester).
4. Usage Method
Pre-Installation Preparation:
Clean mounting surfaces (journal, bearing housing bore) to remove oil stains, iron filings and other impurities; surface roughness should be ≤ Ra 0.8μm.
Check dimensional tolerances of shaft and bearing housing: journal fit tolerance is usually g5/g6, bearing housing bore is H7.
Installation Operation:
Models with inner ring: Heat-mount the inner ring on the journal first (heating temperature 80-100℃), then press the outer ring into the bearing housing bore (apply uniform force with special pressure sleeve, avoid direct tapping).
Models without inner ring: Ensure journal hardness ≥ HRC 58, press-fit the outer ring directly, then insert the shaft into the needle assembly.
Sealed models: Pay attention to the direction of the sealing lip to avoid reverse installation causing seal failure.
Lubrication Supplement:
Non-pre-lubricated models: Fill with corresponding brand grease (e.g., lithium-based grease) after installation, with filling amount accounting for 1/3-1/2 of the internal space of the bearing.
Regular maintenance: Supplement grease every 3-6 months according to working conditions; shorten to 1-2 months in harsh environments.
5. Application Scope
Automotive Industry: Transmissions, clutches, differentials, steering systems, such as synchronizer bearings in manual transmissions.
Machine Tool Equipment: Spindle boxes, feed mechanisms, tool turrets, adapting to the compact structure needs of precision lathes and machining centers.
Construction Machinery: Hydraulic pumps, excavator
Slewing Bearings, loader transmissions, bearing heavy loads and impact loads.
Home Appliances and Office Equipment: Washing machine spindles, printer paper feeding mechanisms, air conditioning compressors, balancing space and performance requirements.
Precision Instruments: Robot joints, medical equipment (e.g., CT machine rotating shafts), scenarios requiring high precision and low noise.
6. Precautions
Installation Taboos: Do not directly tap bearing rings or needles with a hammer to avoid cracks; do not install the bearing at an angle, otherwise it will cause needle jamming.
Load Limitation: Can only bear radial loads; axial loads are strictly prohibited (unless used in combination with
Thrust Bearings), otherwise service life will be significantly shortened.
Environmental Requirements: Avoid unprotected use in dusty, humid (relative humidity ＞85%) and corrosive medium environments; install protective covers if necessary.
Maintenance Points: Clean old grease before supplementing new grease; do not mix greases of different brands; use special pullers for disassembly, prohibit forced prying.
Service Life Warning: Immediately stop the machine for inspection when abnormal noise (＞65dB), temperature rise (exceeding ambient temperature by 40℃) or increased vibration occurs during operation.
7. Packaging and Transportation
Packaging Methods:
Individual Packaging: Plastic blister boxes or paper tubes with buffer materials (e.g., foam) inside to prevent collision;
Bulk Packaging: Put individual packages into corrugated cartons, separated by EPE foam inside; each carton weighs ≤25kg, with model, quantity, gross weight and other information marked outside;
Export Packaging: Cover with wooden pallets, wrapped with stretch film for moisture protection; install corner protectors at pallet corners, complying with ISTA transportation standards.
Transportation Requirements:
Handle with care during transportation, prohibit throwing; stacking height shall not exceed 3 layers;
Transport vehicles shall be dry and clean, avoiding rain and sun exposure; temperature controlled at -20℃~+40℃;
Add rainproof cloth for sea transportation to prevent seawater erosion; fix goods for land transportation to avoid shaking and collision during transit.
Storage Conditions:
Store in a dry and ventilated warehouse; place moisture-proof boards on the ground; keep a distance of ≥50cm from the wall; do not store with corrosive goods; storage period generally does not exceed 12 months (regular turning and inspection required).
Dalian Redmay bearing import & Export Co., Ltd.
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