Cylindrical Roller Bearing Introduction

3 month ago

11 0 

Dalian Redmay bearing import & Export Co., Ltd.

5 month

Product details

1. Core Advantages

Ultimate Load-Carrying Capacity: Adopting a full-complement roller structure (without cage or with guiding cage), the number of rollers is over 30% more than that of ordinary cylindrical roller bearings. The radial rated dynamic load is increased by 40%-60%, enabling it to bear extremely high radial impact loads and heavy loads.

Compact and Efficient Structure: Under the same radial dimension, it provides higher load density, which can adapt to heavy-duty equipment without increasing the bearing installation space, especially suitable for heavy machinery with limited structure.

Strong Operational Stability: Rollers are evenly distributed on the raceway, enabling more balanced force transmission. Combined with high-precision raceway design, its rotational stability under low-speed and heavy-load working conditions is superior to that of similar bearings with cages.

Controllable Maintenance Cost: Some models integrate a sealing structure and are pre-filled with long-acting grease. Combined with the wear-resistant roller and ring design, it reduces the frequency of lubrication and maintenance, lowering the equipment operation and maintenance cost.

2. Key Features

Structural Form: Mainly composed of outer ring, inner ring, full-complement cylindrical rollers, and guides (some with intermediate rings or lightweight cages). Rollers of cage-free models are arranged in direct contact, while models with guides can optimize the roller movement trajectory.

Roller Characteristics: Cylindrical rollers have a diameter of 5-25mm, and the length-to-diameter ratio is usually 1-2.5. The surface is super-finished with roughness Ra ≤ 0.05μm and hardness reaching HRC 60-64, featuring excellent deformation resistance and wear resistance.

Guidance and Limitation: Cage-free models rely on ring flanges to guide rollers; models with intermediate rings can separate rollers and reduce friction; some large bearings are equipped with guide rings to ensure rollers do not skew during relatively high-speed operation (compared to full-complement structures).

Sealing and Lubrication: Models below medium size are often equipped with double-sided contact seals (such as nitrile rubber seal rings), while large models are mostly open-type and require regular grease replenishment. Some special models adopt an oil bath lubrication design.

3. Core Manufacturing Processes

Roller Manufacturing: High-purity bearing steel (SUJ2) or carburized steel (SAE8620H) is used, undergoing cold heading forming → heat treatment (integral quenching or carburizing quenching) → centerless grinding → end face grinding → super-finishing, ensuring the cylindricity error ≤ 0.0015mm.

Ring Processing: Outer/inner rings go through forging blanking → turning rough machining → heat treatment (quenching + tempering) → raceway grinding → flange grinding → super-finishing. The raceway generatrix straightness error ≤ 0.002mm, and the perpendicularity to the flange ≤ 0.003mm.

Assembly Process: Cage-free models adopt the process of "roller sorting → directional arrangement → pressure fitting", ensuring uniform roller distribution through special tooling; models with intermediate rings need to assemble the spacer first, then install rollers in sequence, and finally detect radial clearance.

Quality Inspection: Covers dimensional accuracy (coordinate measuring machine, raceway profiler), hardness testing (Vickers hardness tester), radial clearance detection (clearance gauge), rotational flexibility testing (low-speed rotation tester), and fatigue life testing.

Full Complement Cylindrical Roller Bearing

4. Usage Method

Pre-Installation Preparation:

Thoroughly clean the journal, bearing housing bore, and bearing surface to remove burrs, iron filings, and oil stains. The surface roughness of the mounting surface should be ≤ Ra 1.6μm.

Check the fitting dimensions: The fit tolerance between the journal and inner ring is usually m6/k6, and the fit between the bearing housing bore and outer ring is H7, ensuring the interference fits the design requirements.

Prepare suitable grease (such as extreme pressure lithium-based grease) in advance for open-type bearings, and check the integrity of the seal lip for sealed models.

Installation Operation:

Small and medium-sized bearings: The inner ring is installed by hot fitting (heating temperature 90-110℃, not exceeding 120℃), and the outer ring is cold-pressed into the bearing housing with a pressure sleeve. Direct tapping on the ring end face is prohibited.

Large bearings: Adopt the hydraulic fitting process. The inner ring is expanded by oil pressure and then fitted on the journal, and the outer ring is treated similarly. After assembly, release the oil pressure to achieve a tight fit.

Sealed models: Ensure the seal lip faces the inside of the bearing during installation (the dust-proof side can face outward) to avoid damaging the seal lip during assembly.

Lubrication and Maintenance:

Open-type bearings: Fill with grease immediately after installation. The filling amount should be 2/3-3/4 of the internal space of the bearing, and reduced to 1/2 for high-speed operation (>1500r/min).

Regular maintenance: Replenish grease every 2000-3000 hours under normal working conditions, and shorten to 500-1000 hours in dusty/humid conditions. Old grease must be removed before replenishment.

Oil bath lubrication models: Ensure the lubricating oil level reaches the center of the lowest roller. Regularly check the oil quality and replace it in time if contaminated.

5. Application Scope

Metallurgical Machinery: Work rolls of rolling mills, main shafts of coiling machines, and conveyor rolls of continuous casting machines, which bear the combined working conditions of high temperature and heavy load.

Mining Equipment: Main shafts of crushers, bearing housings of ball mills, and drums of hoists, adapting to impact heavy loads and dusty environments.

Heavy Machine Tools: Spindles of vertical lathes and worktables of gantry milling machines, suitable for precision heavy-load scenarios requiring high rigidity and load-carrying capacity.

Port Machinery: Drums of cranes and rotating shafts of loaders, coping with intermittent heavy loads and complex outdoor environments.

Energy Equipment: Main shafts of water turbines and gearboxes of wind turbines, adapting to low-speed heavy-load and long-term operation requirements.

6. Precautions

Installation Taboos: It is strictly prohibited to directly tap the bearing rings or rollers with a hammer to avoid plastic deformation; the bearing is not allowed to bear axial load (unless with flange design), otherwise it will lead to increased wear on the roller end faces.

Load Limitation: Only applicable to occasions with pure radial load or radial load as the main load. The axial load shall not exceed 5% of the rated radial load. If axial force needs to be borne, it should be used in combination with thrust bearings.

Speed Limitation: Cage-free models have a low limiting speed (usually ≤1500r/min). Over-speed operation is strictly prohibited, otherwise high temperature generated by roller friction will burn the bearing; models with guiding cages can increase the speed appropriately, but refer to the product manual.

Environmental Protection: Protective covers must be installed in dusty, humid, and corrosive medium environments. For sealed models, regularly check the sealing performance and replace immediately if damaged.

Fault Warning: If there is a sudden temperature rise (exceeding the ambient temperature by 50℃), abnormal vibration (amplitude >0.1mm) or abnormal noise during operation, stop the machine immediately for disassembly and inspection, and prohibit operation with faults.

7. Packaging and Transportation

Packaging Methods:

Individual Packaging: Small and medium-sized bearings are packed in plastic sealed boxes, wrapped with anti-rust paper inside, and filled with buffer foam; large bearings are individually fixed with wooden pallets, with anti-rust oil applied on the bearing surface and wrapped with rainproof cloth.

Bulk Packaging: Put individual packages into high-strength corrugated cartons, separated by EPE foam or corrugated partitions inside. Each carton weighs ≤30kg, with marks such as model, quantity, gross weight, "Handle with Care" and "Moisture-Proof" on the outside.

Export Packaging: Adopt fumigated wooden pallets, bearings are sealed with plastic bags, the pallets are wrapped with multiple layers of stretch film for moisture protection, metal corner protectors are installed at the four corners, and attached with commodity inspection certificates conforming to international standards.

Transportation Requirements:

Use forklifts or cranes for handling, avoid manual handling of large bearings to prevent damage; the stacking height shall not exceed 2 layers, and the bottom pallet shall be stably loaded.

Transport vehicles shall be dry and clean, protected from freezing in winter and sun exposure in summer. The temperature shall be controlled at -25℃~+45℃, avoiding severe bumps.

For sea transportation, fix in the container and keep away from the bulkhead and humid areas; for land transportation, fasten the goods with ropes to prevent displacement and collision during transportation.

Storage Conditions:

Store in a dry and ventilated closed warehouse, with moisture-proof pads laid on the ground. Bearings should be ≥10cm away from the ground and ≥60cm away from the wall; avoid storing with corrosive items such as acids, alkalis, and salts. The storage period shall not exceed 18 months, and check the anti-rust condition by turning every 6 months.