How to choose pulley bearing lubricant?

A. Types of Lubricants
Lubricants for pulley bearings are mainly of the following types:
1. Lubricating oil:
Liquid form: Widely used, with good fluidity and cooling properties.
Performance characteristics: Good fluid dynamic lubricity, excellent cooling performance, suitable for high speed, high precision, and high load occasions.
2. Grease:
Semi-solid: Commonly used in medium and low speed scenes, with excellent boundary lubricity and sealing.
Performance characteristics: Not easy to lose, long maintenance cycle, suitable for occasions where it is not easy to refuel, complex environment or dusty.
3. Solid lubricant:
Powder or film: Usually used as an additive for oil and grease, and can also be used independently.
Performance characteristics: Has a wide range of application temperature and strong load-bearing capacity, but has a high friction coefficient and large energy loss.
B. Selection principles
When selecting lubricants for pulley bearings, the following factors need to be considered comprehensively:
1. Operating temperature:
Under high temperature conditions, high viscosity lubricating oil or high temperature resistant grease should be selected.
Under low temperature conditions, low viscosity lubricating oil or low temperature grease should be selected.
2. Load:
Equipment with medium and high loads should use extreme pressure grease lubrication to withstand greater pressure.
Low-load equipment can use ordinary lubricating oil or grease.
3. Speed:
High-speed bearings are suitable for oil lubrication because lubricating oil has better fluid dynamic lubricity.
Low-speed bearings are suitable for grease lubrication because grease has excellent boundary lubricity and sealing.
4. Working environment:
If there are impurities, high temperature, corrosion or conductivity in the environment, grease should be selected.
If the environment is clean and maintenance is simple, lubricating oil can be selected.
5. Equipment structure and precision:
The smaller the effective space or clearance inside the bearing, the higher the machining precision of the working surface, and low-viscosity grease should be selected to reduce energy loss.
The rough surface should increase the viscosity of the grease to enhance the formation of the oil film.
C. Specific selection method
1. Select according to dn value:
When the dn value (bearing inner diameter × speed) is less than (1.5~2)×10^5, grease should be selected.
When the dn value is greater than (1.5~2)×10^5, select lubricating oil.
2. Consider lubricant performance:
Lubricating oil has good fluid dynamic lubricity, cooling and bearing supply ability, and is suitable for high speed and high precision occasions.
Grease has good boundary lubricity, sealing and corrosion resistance, and is suitable for medium and low speed and complex environment occasions.
3. Comprehensive consideration:
When selecting lubricants, factors such as mechanical structure, lubrication method, maintenance and economy should also be considered.

D. Addition and maintenance of lubricants
1. Lubrication method:
Select a suitable lubrication method according to the specific situation of the equipment, such as oil bath lubrication, splash lubrication, circulating oil lubrication, etc.
Lubricate the pulley nnground ball bearing regularly to ensure that the lubricant is sufficient and clean.
2. Maintenance and replacement:
Check the quality and quantity of lubricants regularly, and replace aging and contaminated lubricants in time.
Clean the bearings and lubrication system to keep them clean and dry.