The selection of lubricating grease for single row tapered roller bearings should focus on six core factors: speed, temperature, load, sealing performance, environmental conditions, and economy. Specific precautions are as follows:
1. Speed matching: Select the cone penetration degree according to the speed
Low speed and heavy load: Choose lubricating grease with low cone penetration degree (high viscosity), such as 0 or 1 grease, to provide sufficient oil film strength and anti extrusion performance.
High speed: Priority should be given to lubricating grease with high cone penetration and good mechanical stability (such as No.2 or No.3 grease). The viscosity of the base oil should be low to reduce operating resistance.
. For example, lithium based grease is often used for high-speed motor bearings, which has excellent mechanical stability and can effectively reduce temperature rise.2. Temperature adaptability: Ensure that the working temperature is within the allowable range of the lubricating grease
High temperature conditions: Select lubricating grease with a drip point 10-20 ℃ higher than the actual maximum working temperature (synthetic lubricating grease needs to be 20-30 ℃ higher).
. For example, in environments above 100 ℃, fluorocarbon grease or composite lithium based grease should be used to avoid lubrication failure due to insufficient drip points. Low temperature environment: In extremely cold regions (below -20 ℃), lithium based low-temperature grease should be used to ensure fluidity at low temperatures and prevent dry friction during start-up.3. Load characteristics: Lubrication performance needs to be strengthened for heavy loads or impact loads
Heavy loads: Use lubricating grease with small cone penetration and containing extreme pressure additives (such as molybdenum disulfide) to enhance oil film strength and wear resistance.
. For example, mining machinery bearings often use lithium grease containing EP additives to withstand high impact loads. Vibration condition: Avoid using lubricating grease with poor mechanical stability to prevent vibration from causing soap fiber structure collapse and lubrication failure.4. Sealing performance: Choose the type of lubricating grease according to the sealing design.
Open type bearings: Regularly replenish lubricating grease, choose grease with good water resistance and strong adhesion (such as calcium based or lithium based grease) to prevent impurities from entering.
. Sealed bearings: After initial filling, there is no need to replenish frequently, but it is necessary to ensure that the seals are intact to avoid grease leakage or external contamination.5. Environmental conditions: Targeted response to humidity, corrosive media, etc.
Wet environment: Choose calcium based or composite calcium sulfonate lubricating grease with excellent water resistance to prevent moisture from entering and causing rust.
.Corrosive media: In chemical, marine and other environments, use synthetic lubricating grease that is resistant to chemical media (such as fluorocarbon grease) to avoid grease decomposition and failure.
.Dusty environment: Choose lubricating grease with strong adhesion and good dustproof performance to reduce dust entering the bearing interior.
.6. Economy and maintenance cycle: Balance cost and efficiency
Long life requirement: Choose lubricating grease with good high-temperature stability and strong oxidation stability (such as perfluoropolyether grease) to extend the grease replacement cycle and reduce maintenance costs.
.Cost sensitive scenario: While meeting performance requirements, prioritize the use of cost-effective general-purpose lubricants (such as lithium based grease) to avoid excessive use of high-end products.
.7. Compatibility: Avoid mixing different types of lubricating grease
When replacing lubricating grease, it is necessary to thoroughly remove the old grease to prevent chemical reactions between different components, which can lead to decreased lubrication performance or bearing damage.
. For example, mixing sodium based grease with lithium based grease may result in precipitation and loss of lubrication.8. Filling amount control: Avoid excessive or insufficient
Filling amount principle: The less filling amount, the better, while ensuring sufficient lubrication.
. Overfilling can lead to an increase in rolling element resistance and excessive temperature rise; Insufficient conditions may cause dry friction and accelerate wear.Empirical formula: For open type bearings, the filling amount can refer to 1/3 to 1/2 of the bearing chamber cavity volume; High speed bearings need to further reduce the filling amount.