9 Common Misconceptions About Bearing Lubrication - Part 1
No equipment can operate without lubrication. However, in actual production, people often fall into lubrication misconceptions due to various reasons. For example, believing that any oil can provide lubrication, or that higher viscosity oil means better performance. Below are 9 common lubrication misconceptions for reference.
1. Believing the sole purpose of lubrication is to make machines run faster
Friction and wear occur on the contact surfaces of relatively moving parts in machines. Statistics show that more than one-third of the world's energy is consumed by frictional losses. When wear exceeds the allowable limit, it directly affects the normal operation and service life of machines. Therefore, lubricants are added between relatively moving parts to form an oil film, which reduces friction and wear. They also serve functions such as cooling, shock absorption, and sealing.The purpose of lubrication is not only to make machines run faster, but more importantly to ensure their normal operation and extend service life.
2. Mistakenly thinking any oil can provide lubrication
Lubricating oils come in different types with varying operating properties. Additives are often incorporated to enhance specific performance aspects of the oil.To achieve proper machine lubrication, different types of lubricating oils and additives should be selected based on factors such as machine type, operating conditions, and oil supply method.
3. Assuming more lubricant means better lubrication
For grease lubrication, excessive grease increases resistance, causes bearing overheating, and leads to grease leakage—especially in high-speed, heavy-load machines.For oil lubrication, oil level indicators are typically used to monitor the oil level. For example, the oil immersion depth of high-speed large gears in gearboxes should ideally be 1-2 tooth heights. This prevents insufficient lubrication of high-speed gears while reducing gear resistance and oil temperature rise. The grease filling amount for rolling bearings generally should not exceed 1/3 to 1/2 of the bearing internal space.
4. Believing higher viscosity oil delivers better lubrication
Viscosity is a key indicator of lubricating oil. Its standard is usually determined at 100°C to classify oil grades. Higher-grade oils form thicker oil films, which reduce friction between contact surfaces but increase resistance. This leads to greater power loss and energy waste.When machines start up, temperatures are low. After operating for a period, the lubricating oil on friction surfaces partially drains due to temperature rise, failing to form an effective oil film. High-viscosity oil flows slowly, making it difficult to quickly replenish the friction surfaces and resulting in increased component wear.Data shows that reducing lubricating oil viscosity by 1 mm²/s can save 15% of fuel. Viscosity selection should consider factors such as operating speed and temperature. Lower viscosity in lubricating oils is currently one of the measures for fuel conservation.
