11 ways to lubricate bearings

The purpose of bearing lubrication is to enable the bearing to operate normally, avoid direct contact between the raceway and the rolling element surface, reduce friction and wear inside the bearing, extend the service life of the bearing, enhance the performance of the bearing, and also prevent the intrusion of foreign matter into the bearing. internally causing rust and corrosion.

1. Manual lubrication

   This is the most primitive method. When the bearing's lubricating oil is insufficient, use an oiler to supply oil. However, this method is difficult to maintain a constant amount of oil. There is a greater risk of forgetting to refuel due to negligence. It is usually only used in light load, low speed or intermittent motion situations. It is best to install a dust cover or ball valve on the refueling hole during operation. And use felt, cotton, wool, etc. as filter devices.

2. Dropping point lubrication

   Usually used for light-load and medium-load bearings with a circumferential speed less than 4 to 5 m/s. A roughly quantitative amount of lubricating oil is supplied from the container through holes, needles, valves, etc. The most classic one is the dripping oil cup. The amount of dripping oil varies with the lubrication. Oil viscosity, bearing clearance and oil supply hole location vary significantly.

3. Oil ring lubrication

   The lubricating oil from the oil pool is brought to the bearing by a ring that is hung on the shaft and can rotate (can only be used for horizontal shaft lubrication). It is suitable for medium-speed and high-speed bearings with a shaft diameter greater than 50mm. The oil ring is preferably Seamless, when the bearing width-to-diameter ratio is less than 2, only one oil ring can be used, otherwise two oil rings are required.

4. Oil rope lubrication

   Relying on the capillary and siphon action of the oil rope, the lubricating oil in the oil cup is introduced into the bearing. It is mainly used for light-load and medium-load bearings with a peripheral speed of less than 4 to 5 m/s. In addition, the oil rope can filter during the entire process. role.

5. Oil pad lubrication

   The capillary action of the oil pad is used to apply the lubricating oil in the oil pool to the surface of the shaft diameter. This method can keep the friction surface clean at all times, but dust will also block the capillary holes and cause insufficient oil supply. The oil supply amount of oil pad lubrication is usually only 1/20 of that of oil lubrication.

6. oil bath lubrication

   This lubrication method is to immerse part of the bearing in lubricating oil. It is often used for thrust bearings of vertical shafts, but is not suitable for radial bearings of horizontal shafts.
   

7. splash lubrication

   The lubricating oil splashed by the beating of the rotating parts in the oil tank is supplied to the bearings, and is suitable for higher speed bearings.

8. spray lubrication

   The lubrication method of atomizing lubricating oil and spraying it on the friction surface is suitable for high-speed bearings.

9. Pressure oil supply lubrication

   The pressure of the lubrication pump supplies oil to the bearings, and the lubricating oil flowing out of the bearings is recovered into the oil pool for recycling. It is the most stable lubrication method with the largest oil supply, and is suitable for high-speed, heavy-loaded, and important sliding bearings.

10. Circulating oil lubrication

    Use an oil pump to transport the filtered oil to the bearing components. The lubricating oil after passing through the bearing is filtered and cooled before use. Since the circulating oil can take away a certain amount of heat and cool down the bearing, this method is suitable for bearing parts with higher rotating speeds.
    

11. Jet lubrication

    Use an oil pump to inject high-pressure oil into the bearing through the nozzle, and the oil injected into the bearing flows into the oil groove through the other end of the bearing. When the bearing rotates at high speed, the rolling elements and cage also rotate at a very high speed to form an airflow in the surrounding air. It is difficult to send lubricating oil to the bearing using general lubrication methods. At this time, the lubricating oil must be sprayed with high-pressure injection. In the bearing, the position of the nozzle should be between the inner ring and the center of the cage.

    Bearing lubrication is a continuous task, and the lubricating oil replacement cycle is based on the use conditions of the bearing and the amount of oil. Under normal circumstances, when used in a good environment with an operating temperature below 50°C and little dust, it should be replaced once a year. When the oil temperature reaches 100°C, it should be replaced once every 3 months or less.