Double row tapered roller bearings require maintenance. As a key component with high precision and load-bearing capacity, its maintenance is directly related to the stability, lifespan, and safety of equipment operation. The following is a detailed analysis:
1. The necessity of maintenance for double row tapered roller bearings
The structural characteristics determine the maintenance requirements. Double row tapered roller bearings consist of an inner ring, an outer ring, two rows of rollers, a cage, and a sealing device (if any). The rollers are in line contact with the raceway and have a high load-bearing capacity but relatively high friction.
. If the lubrication is insufficient or impurities invade, it can easily lead to wear of the raceway, breakage of the retaining frame, or abnormal temperature rise, thereby causing equipment failure.The influence of operating environment: High temperature environment: Lubricating grease is prone to oxidation and deterioration, losing its lubrication performance.
.Wet or corrosive environment: Bearing materials may rust, and seal aging may accelerate.
. Heavy load or impact load: The raceway and rollers are prone to fatigue peeling and require maintenance to extend their lifespan.Due to economic considerations, the cost of regular maintenance is much lower than the replacement of damaged bearings and equipment downtime losses.
. For example, in wind turbine gearboxes, bearing failures can result in repair costs ranging from tens of thousands to hundreds of thousands of yuan.II. Maintenance content of double row tapered roller bearings
1. Lubrication management
Lubrication method selection: grease lubrication: suitable for medium and low speed, medium and low temperature environments (such as machine tool spindles), extreme pressure lithium based grease or synthetic grease (such as polyurea based grease) should be selected.
.Oil lubrication: Suitable for high-speed and high-temperature environments (such as car transmissions), it needs to be supplied through oil baths, fuel injection, or circulating oil systems.
. Lubrication cycle and amount: Lubricate with grease: replenish every 500-1000 hours of operation, with a replenishment amount of 1/3-1/2 of the bearing cavity.Oil lubrication: Replace regularly based on oil analysis results, usually every 2000-5000 hours.
. Lubrication effect inspection: By analyzing the oil sample to detect the content of metal particles, the degree of wear can be determined.When touching the outer ring temperature of the bearing, it should normally be lower than the ambient temperature by+30 ℃. If it rises abnormally, it may be due to insufficient lubrication.
.2. Cleaning and Dust Prevention
Pre installation Cleaning: Clean the bearings and installation areas with anhydrous ethanol or specialized cleaning agents to avoid cotton yarn residue fibers.
.Protection during operation: Install dust covers or sealing rings to prevent dust and metal shavings from entering.
. Regularly clean the environment around the equipment to reduce the source of impurities. Shutdown maintenance: If the bearing is not used for a long time, it should be coated with anti rust oil and wrapped in moisture-proof paper, and stored in a dry environment (humidity ≤ 60%).3. Temperature and vibration monitoring
Temperature monitoring: Use an infrared thermometer or built-in temperature sensor to monitor the bearing temperature in real time.
. A sudden temperature rise (such as exceeding 80 ℃) may indicate lubrication failure or overload, and immediate shutdown inspection is required. Vibration analysis: Detecting bearing fault characteristic frequencies (such as inner ring, outer ring, and roller fault frequencies) through vibration spectrum analysis. When the vibration value exceeds the ISO 10816 standard, further inspection of the bearing condition is required.4. Pre tightening force adjustment
Pre tightening purpose: to eliminate axial clearance, improve rotation accuracy and stiffness, reduce vibration and noise.
.Adjustment method: Adjust the axial clearance with a nut or spring, and measure the displacement with a dial gauge.
.Excessive pre tension can easily cause overheating, while insufficient pre tension may cause vibration, and should be adjusted according to the manufacturer's recommended values.
.5. Alignment and installation inspection
Alignment accuracy: The alignment error between the shaft and the bearing seat should be ≤ 0.05mm, otherwise it will cause additional load and early failure.
.Installation tool: Use a hydraulic press or induction heater for installation, avoid directly tapping the inner or outer ring of the bearing.
.Fit tolerance: The inner ring has an interference fit with the shaft (such as H7/p6), and the outer ring has a clearance fit with the seat hole (such as H7/h6), and the fit tightness needs to be checked regularly.