Spherical Roller Bearing 21313RZW33 KOYO

The KOYO 21313RZW33 is a high-performance self-aligning roller bearing, specifically engineered for heavy radial loads and scenarios requiring self-alignment to compensate for shaft deflection and installation misalignment. It fully complies with ISO 355 and DIN 628 standards, with suffixes denoting key configurations: R for no separable inner ring, Z for single-sided metal shield, W33 for outer ring with oil groove and three oil holes, ensuring efficient lubrication and heat dissipation. Its unique design combines strong load-bearing capacity, excellent self-alignment performance and convenient lubrication, distinguishing itself from ordinary bearings in harsh industrial environments.

1. Detailed Dimensional Parameters: Conforming to international bearing standards, the bearing has an inner diameter (d) of 65mm, outer diameter (D) of 140mm, and width (B) of 33mm. The minimum chamfer size (rₘᵢₙ) is 2.1mm, single weight is 2.2kg. Its tolerance grade is P0 (ISO 492), with inner/outer diameter tolerance of IT6 and width tolerance of IT7. The basic dynamic load rating is 195kN, basic static load rating is 218kN, reference speed (grease lubrication) is 3200r/min, and limiting speed (oil lubrication) is 4300r/min. The W33 oil groove and oil holes enable continuous lubrication, adapting to long-term heavy-duty operation.

2. Specific Material Description: Inner ring, outer ring and cylindrical rollers are made of high-carbon chromium bearing steel (AISI 52100/SUJ2, equivalent to GCr15), refined by vacuum degassing technology to reduce non-metallic inclusions. After precision heat treatment, it reaches a hardness of 61-65 HRC, featuring excellent wear resistance, high fatigue strength and stable dimensional accuracy under cyclic loading. The retainer is made of pressed steel (SPCC), with good impact resistance and wear resistance, ensuring stable roller guidance. The Z-type metal shield is made of carbon steel, providing effective dust protection, while the W33 oil groove structure enhances lubrication efficiency.

3. Core Processing Technology: Key manufacturing processes follow KOYO’s stringent quality standards: closed-die forging, CNC turning, controlled atmosphere heat treatment, precision grinding and superfinishing. Closed-die forging ensures dense internal structure and continuous metal fibers, enhancing bearing rigidity. CNC turning achieves Ra ≤ 0.3μm surface roughness, ensuring precise dimensional control. Heat treatment adopts nitrogen-hydrogen atmosphere to avoid oxidation and decarburization. Precision grinding with CBN砂轮 and superfinishing reduce raceway roughness to Ra ≤ 0.04μm, minimizing friction. The W33 oil groove and oil holes are precision machined to ensure smooth lubricant circulation, extending service life.

4. Service Life: Under standard working conditions (2800r/min, radial load 70kN, proper lubrication and clean environment), the L₁₀ basic rated life (90% reliability) is 22,000 operating hours, calculated in accordance with ISO 281:2007 standard and KOYO’s life prediction model. Key influencing factors include lubrication quality, contamination level, installation accuracy and load magnitude; insufficient lubrication or excessive contamination can reduce service life by 30-50%.

5. Application Scenarios and Industries: Widely used in machinery manufacturing, mining, engineering machinery, rolling mills and power generation industries. Typical applications include rolling mill equipment, crushers, conveyor systems, centrifugal pumps and heavy-duty gearboxes. It is suitable for these scenarios due to its excellent self-alignment performance (compensating for shaft deflection), W33 lubrication structure (continuous lubrication), and high load-bearing capacity, adapting to heavy-duty, high-temperature and dusty working conditions.

6. Basic Maintenance Requirements: Maintenance cycle is 2000 operating hours. Lubrication: Lithium-based grease (NLGI 2) or extreme pressure gear oil (ISO VG 68), filling amount 15-30% of bearing free space; re-lubricate every 1500-2000 hours via W33 oil holes. Cleaning: Clean surface and shield with clean kerosene; avoid corrosive cleaners. Regular inspection: Check for abnormal noise, temperature rise and grease leakage; replace lubricant if deteriorated.

7. Installation Precautions: Pre-installation: Keep area clean, remove burrs from shaft/housing, check fitting surface roughness (Ra ≤ 0.8μm). Installation: Apply thin oil film, press evenly on inner ring (no tapping), ensure coaxiality tolerance ≤ 0.02mm. Fastening torque: 120-150N·m for bearing seat bolts. Post-installation: Rotate manually to check jamming; measure temperature after 30 minutes (normal ≤ 72℃). Safety: Wear protective gloves/goggles, use specialized lifting tools.