Grease lubrication and oil lubrication of bearings

 

 

Abstract:

The main purpose of bearing lubrication is to use lubricant to form an isolating lubricating oil film on the friction surfaces between the rings, rolling elements and cages to reduce bearing friction and wear, prevent sintering, and extend the service life of the bearing. In addition, lubricants can also prevent bearing corrosion, reduce vibration and noise, provide cooling, and prevent the intrusion of external foreign matter.

 

Key words: Grease lubrication, oil lubrication, bearing lubrication, high-speed precision bearings, oil mist lubrication, oil-gas lubrication, oil injection lubrication.

The main purpose of bearing lubrication is to use lubricant to form an isolating lubricating oil film on the friction surfaces between the rings, rolling elements and cages to reduce bearing friction and wear, prevent sintering, and extend the service life of the bearing. In addition, lubricants can also prevent bearing corrosion, reduce vibration and noise, provide cooling, and prevent the intrusion of external foreign matter.

 

Grease lubrication

1. Grease lubrication has become the most commonly used lubrication method for bearings because of its ease of use and simple maintenance.

The most commonly used grease for rolling bearings is bonded grease with mineral oil as the base oil. This grease has good adhesion and has good lubrication effect in a wide temperature range and speed range. The applicable temperature range is -30°C~+110°C.

2. When high-speed precision bearings are lubricated with grease, the recommended filling amount of grease is 15% to 20% of the free space inside the bearing.
3. Grease-lubricated bearings must be run-in in the early stages of operation. After running-in, excess grease is forced into the bearing raceway, making the grease in the bearing evenly distributed and ensuring the lowest thermal balancetemperature when the bearing is operating normally.
4. Grease should be replenished and replaced within a certain period of time. When replenishing grease, it should be noted that different types and specifications of grease cannot be mixed, otherwise the performance of the grease will be reduced. In addition, the original grease should be cleaned when replacing the grease.

 

Oil lubrication

When grease lubrication cannot meet the high performance requirements of the machine tool, oil lubrication can be used. The most commonly used oil lubrication methods for machine tool spindle bearings include oil mist lubrication, oil-gas lubrication, and oil injection lubrication.

 

 

Lubrication method	Advantages
Oil mist lubrication	New lubricating oil is continuously injected, oil deterioration will not occur. Dust and cutting fluid are not easily infiltrated
Oil-gas lubrication	It can control the optimal amount of oil, with low bearing heating, good cooling effect and low temperature rise. Dust and cutting fluid are not easily immersed. No environmental pollution.
Oil injection lubrication	Due to the large flow rate, dust and cutting fluid will not enter the bearings and will not burn the bearings. The oil injection takes away the heat and the temperature rise of the bearing can be controlled.

 

 

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