Single row four point angular contact bearing is a specially designed rolling bearing, which is characterized by bearing radial and axial loads simultaneously through four contact points (two each between the inner ring and the ball, and two between the outer ring and the ball), with high rigidity, high load-bearing capacity, and bidirectional axial positioning function. The following is a detailed explanation of its usage:

1. Preparation before installation

Bearing selection verification

Load matching: Calculate the equivalent load (P=X · Fr+Y · Fa, X/Y is the load factor) based on the radial force (Fr) and axial force (Fa) borne by the equipment, ensuring that the rated dynamic load (C) of the bearing meets the requirements (C ≥ P · n ^ ε, n is the speed, ε is the life index).

Speed limit: Confirm that the maximum speed of the bearing (dn value, i.e. inner diameter x speed) does not exceed the standard value (usually 300000~500000 mm/min) to avoid high temperature failure.

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Pre tightening requirement: If you need to increase rigidity or reduce vibration, you need to choose pre tightening bearings (such as light pre tightening, medium pre tightening) and equip them with pre tightening springs or adjusting washers.

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Environmental inspection

Cleanliness: Before installation, wipe the shaft, bearing seat, and bearing surface with a dust-free cloth to prevent dust, metal shavings, and other impurities from entering and prevent early wear.

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Temperature matching: Ensure that the temperature of the bearing, shaft, and bearing seat is consistent (temperature difference ≤ 5 ℃) to avoid changes in fit interference caused by thermal expansion and contraction.

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Lubricant selection: Choose lubrication method according to working conditions:

Lubricating grease: Suitable for scenarios with medium and low speeds (n ≤ 5000rpm) and temperatures ≤ 80 ℃, lithium based grease (such as NLGI No.2) is recommended.

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Oil lubrication: suitable for high-speed (n>5000rpm) or high-temperature environments, can be lubricated with drip oil, oil bath or circulating oil.

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2. Installation steps and precautions

Shaft and bearing seat fit

Inner ring and shaft: Use interference fit (H7/k6 or H7/m6), and the interference fit should be determined according to the bearing inner diameter and speed (refer to ISO 286-2 standard).

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Outer ring and bearing seat: usually with clearance fit (J7/h6), easy to install and compensate for thermal expansion. Heating installation: For bearings with large interference, induction heaters (temperature ≤ 120 ℃) can be used to evenly heat the inner ring to avoid local overheating and annealing.

Bearing installation direction

The particularity of four point contact bearings: there are blocking edges on both sides of the inner ring, and there are no blocking edges on the outer ring. During installation, it is necessary to ensure:

Axial positioning: the outer ring is fixed by the bearing seat shoulder or locking nut, and the inner ring is positioned by the shaft shoulder or retaining ring to prevent axial movement.

. Contact angle alignment: During installation, maintain the original contact angle of the bearing (usually 35 °~45 °) to avoid uneven load distribution caused by tilting.

Pre tightening adjustment (if necessary)

Spring pre tightening: Install a wave spring or disc spring between the outer ring of the bearing and the bearing seat, and apply pre tightening force through elastic deformation.

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Adjusting gasket pre tightening: Install gaskets of different thicknesses on the shaft and achieve pre tightening by changing the axial position of the inner ring (using a dial gauge to measure the pre tightening amount, usually 0.02~0.05mm).

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Sealing and Protection

Dust Sealing: Install rubber sealing rings (such as RS type) or metal dust covers (such as ZZ type) on both sides of the bearing to prevent dust and moisture from entering.

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Shaft end seal: For the exposed shaft end, a labyrinth seal or oil slinger design is used to reduce lubricant leakage.

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III. Operation and Maintenance

Initial Operation

Low speed running in: After installation, run at low speed (30%~50% of rated speed) for 1-2 hours to fully distribute the lubricant and check for vibration and noise.

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Temperature monitoring: Use an infrared thermometer or temperature sensor to monitor the temperature of the outer ring of the bearing. The normal operating temperature should be ≤ 80 ℃, and any abnormal temperature rise should be immediately stopped for inspection.

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Regular maintenance

Lubrication supplement:

Lubricating grease: Supplement lubricating grease every 2000-5000 hours of operation (the replenishment amount is 1/3~1/2 of the initial filling amount).

. Oil lubrication: Regularly check the oil level (oil bath lubrication) or oil pressure (circulating oil lubrication), and the replacement cycle is determined based on the analysis results of the oil product.

Vibration analysis: By monitoring the vibration spectrum of the bearing through a vibration sensor, if there is a 1-fold (shaft frequency) or 2-fold vibration, it may indicate insufficient preload or damage to the raceway.

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Common troubleshooting

Abnormal noise:

Metal friction noise: Insufficient lubrication or damaged ball bearings, requiring additional lubrication or replacement of bearings.

. Periodic impact sound: If the cage breaks or the raceway is corroded, the machine should be stopped immediately for replacement.

Axial movement: If the preload fails or the seal is damaged, it is necessary to readjust the preload or replace the seal.

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High temperature: Poor lubrication, overload, or installation tilt. It is necessary to check the lubrication system, load distribution, and installation accuracy.

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IV. Application Scenarios and Advantages

Typical Applications

Machine Tool Spindle: Utilizing its high rigidity to achieve high-precision machining (such as CNC milling machines and grinders).

. Reducer: It can withstand the radial and axial forces generated by gear meshing, extending its service life.

Pumps and compressors: Maintain stable operation under high-speed rotating conditions, reducing vibration and noise.

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Core Advantages

Bi directional Axial Load Bearing: A single bearing can withstand bi-directional axial forces, simplifying structural design.

. High rigidity: The four point contact design reduces elastic deformation and improves system dynamic response.

Long life: Optimize contact angle distribution to reduce stress concentration and extend fatigue life.

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Fifth, Summary of Precautions

Do not directly strike: During installation, avoid using a hammer to directly strike the inner or outer ring of the bearing, and use a special pressing sleeve or heating method.

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Avoid mixing lubricants: Different brands of lubricants may undergo chemical reactions and need to be thoroughly cleaned before replacement.

. Regular calibration: For high-precision equipment, calibrate the bearing preload and axial clearance every 6-12 months to ensure stable performance. By standardized installation, reasonable lubrication, and regular maintenance, single row four point angular contact bearings can significantly improve the reliability and lifespan of equipment operation, and reduce the overall lifecycle cost.