A single row four point angular contact ball bearing (such as QJ type, with a contact angle usually of 35 ° or 45 °) is a specially designed separated single row angular contact ball bearing that can withstand bidirectional axial loads and smaller radial loads, suitable for high axial loads, high-speed operation, or space limited scenarios. Here are its specific usage methods:
1. Preparation before installation
Cleaning and inspection
Use gasoline or kerosene to clean bearings and fittings (such as shafts and bearing seats), remove oil stains, impurities, and rust inhibitors. Check the appearance of the bearing for cracks, rust, or wear, and confirm that the raceway and rolling elements are not damaged. Measure the dimensions of the shaft and bearing seat to ensure that the tolerances meet the requirements (e.g. shaft h5-h7, bearing seat J6-J7).
Lubrication selection
Choose lubrication method according to working conditions:
Lubricating grease: suitable for medium and low-speed applications, choose non impurity, anti-oxidation, and rust proof lubricating grease (such as lithium based grease), with a filling amount of 30% -60% of the bearing cavity.
.Oil lubrication: suitable for high-speed or high-temperature environments, viscosity grade should be selected according to the working temperature (such as ISO VG 32-68). Sealed bearings (such as those with dust covers or sealing rings) have been filled with lubricating grease and do not require additional addition.
2. Installation Method
Conventional installation (with small interference)
Press the inner or outer end face of the bearing with a sleeve at room temperature, tap the sleeve with a hammer, and evenly press the ring through the sleeve.
. It is recommended to use a hydraulic press during batch installation to ensure even pressing force and avoid damaging the bearings.Heating installation (large interference fit)
Oil bath heating (80-100 ℃) or sensor heating of bearings should be used, and the temperature should not exceed 120 ℃.
.Install quickly after heating and tighten with nuts or other methods to prevent gaps between the sleeve and the shaft shoulder after cooling.
.Installation precautions
Separate structure: The inner ring of a four point contact ball bearing is usually designed as a double half inner ring. During installation, the outer ring, cage, and steel ball assembly need to be installed separately from the double half inner ring.
.Directionality: Ensure that the contact angle direction of the bearing is consistent with the direction of force, and avoid reverse installation that may cause a decrease in load-bearing capacity.
. Pre tightening force: Adjust the pre tightening force according to the working conditions to eliminate gaps and improve rigidity, but avoid excessive pre tightening that may cause heating or wear.III. Use and Maintenance
Operation Monitoring
Temperature: The bearing temperature should be below 80 ℃. If the temperature is too high, the machine should be stopped to check for lubrication or installation issues.
.Vibration and noise: Use a vibration meter to detect the vibration value of the bearing. If it exceeds the reference value (such as ISO 10816 standard), further analysis of the cause is required.
. Clearance adjustment: Regularly check the bearing clearance to ensure it meets the design requirements (usually 0.05-0.15mm).Lubrication and maintenance
Lubricating grease: Supplement lubricating grease according to the working conditions, and the replenishment cycle is generally 3-6 months.
. Oil lubrication: Regularly replace the lubricating oil and clean the oil circuit and filter.Regular inspection
Appearance inspection: Check whether the bearings have cracks, wear, or rust, and whether the cage is loose or damaged.
.Clearance inspection: Use a feeler gauge or dial gauge to measure the axial and radial clearance of the bearing. If it exceeds the standard value, the bearing needs to be replaced.
.4. Disassembly and Replacement
Disassembly Method
Use a specialized puller to disassemble the bearing, avoiding direct hammering with a hammer to prevent damage to the shaft or bearing seat.
. After disassembly, check the wear of the bearings and fittings, and repair or replace them if necessary. Replacement CriteriaWhen the following situations occur, the bearing needs to be replaced:
The rolling elements or raceways have severe wear, jamming, or cracks.
. The holder is severely deformed or damaged. The bearing clearance exceeds the standard value. Abnormal noise or vibration is generated during operation.Fifth, Application Scenario Example
Engine: withstands bidirectional axial and radial loads at high speeds.
.Lifting machinery: withstand alternating axial forces during lifting and lowering.
. Robot joints: In situations where compact structure and high rigidity are required, while also bearing multi-directional loads. Machine tool spindle: Used in combination with cylindrical roller bearings to optimize lubrication and improve load-bearing capacity.