How to select lubricating oil when using bearings

Due to friction conditions (load, speed, temperature), working conditions (continuous operation, intermittent operation, vibration, impact, etc.), and working environment (humidity, temperature, air pollution, etc.), the selection of lubricating grease can also be caused. However, there are many types of lubricating greases, how to choose lubricating greases correctly and reasonably?

Lubricating oil has an extremely important impact on the operation and service life of bearings. Here is a brief introduction to the general principles of selecting grease. Lubricating grease consists of base oil, thickener, and additives. The performance of different types, types, and brands of greases varies greatly, and the allowable rotational limits vary. Be careful when choosing. The performance of lubricating grease mainly depends on the base oil. Generally, low viscosity base oil is suitable for low temperature, high speed, and high viscosity lubricating grease is suitable for high temperature and high load. Viscosity also affects lubrication performance, and the water resistance of thickeners determines the water resistance of lubricating greases. In principle, different brands of grease cannot be mixed, and even greases with the same thickening agent can have adverse effects due to different additives.

Manual lubrication of non-standard bearings: This is a relatively primitive method. When the smooth oil of non-standard bearings is insufficient, use a oiler to supply oil. However, this method is difficult to maintain a certain amount of oil because of the high risk of refueling, which is generally only used in situations of light load, low speed, or intermittent movement. A better operation method for heavy bearing seats is to install a dust cap or ball valve at the refueling port, and use felt, cotton wool, etc. as filtering equipment.

Non standard bearing drop point lubrication: generally used for light and medium load non standard bearings with a circumferential speed of less than 4~5m/s, providing approximately a quantitative amount of smooth oil from containers through holes, needles, valves, etc. The classic is an oil drip cup, where the amount of oil drops varies significantly with the viscosity of the smooth oil, non-standard bearing clearance, and the direction of the oil supply hole.

Non standard bearing oil ring lubrication: The smooth oil from the oil pool is brought into the non standard bearing through a ring that is suspended on the shaft and rotated (only for horizontal shaft smoothing methods). Suitable for medium and high speed non-standard bearings with a shaft diameter greater than 50mm. The oil ring is seamless. When the non-standard bearing width ratio is less than 2, only one oil ring can be used, otherwise two oil rings need to be used.

Non standard bearing oil rope lubrication: Relying on the capillary and siphon action of the oil rope, the smooth oil in the oil cup is introduced into non standard bearings, mainly used for light and medium load non standard bearings, with a circumferential speed of less than 4~5m/s. In addition, the oil rope can also filter the entire process.

The use temperature of lubricating grease should be at least 20 to 30 degrees lower than its drop point, which is related to the use speed, load, environmental conditions, grease supply method, working state of the friction pair, and working state of the friction pair. The variety of lipids should be minimized to improve economic benefits.