Precautions for using grease in bearings


  Lubrication is an important part in the use of b […]


Lubrication is an important part in the use of bearings. Therefore, many people think that the more grease used, the better the bearing. In fact, the amount of grease actually has a limit.


The general grease filling amount in the bearing can refer to the following principles:
(1) Generally, the bearing should not be filled with grease, and it can be installed to 1/2-3/4 of the entire space of the bearing inner cavity;


(2) The horizontal bearing fills 2/3-3/4 of the inner cavity space;


(3) Vertically installed bearings fill 1/2 (upper side) and 3/4 (lower side) of the cavity space;


(4) In an environment that is prone to pollution, for low-speed or medium-speed bearings, the entire space in the bearing and bearing box should be filled;


(5) For high-speed bearings, put the bearings in high-quality lubricating oil before filling them with grease. Generally, they should be soaked in the base oil of the grease installed, so as to avoid the bearings from burning out due to insufficient grease on the friction surface during start-up.



Bearing grease is usually expressed by apparent viscosity or similar viscosity. When stating the viscosity of the grease, the temperature and shear rate must be specified. A similar viscosity index can be used to control its low temperature fluidity and pumpability.


One of the important indicators to measure the low-temperature performance of TIMKEN bearing grease is the low-temperature torque, that is, the degree to which the grease blocks the low-speed flow bearing rotation at low temperature (below -20°C). The low-temperature torque of the grease is determined by the starting torque and The average value of the torque after turning 60mm is indicated.


The evaporability (degree) of bearing grease indicates the degree of volatilization of the grease when the grease is used for a long time under high temperature conditions. The lower the evaporability, the better. The evaporation of fat mainly depends on the nature and fraction composition of lubricating oil.


Oxidation stability refers to the ability of a grease to resist the effects of heat and oxygen and maintain its properties without permanent changes when it is stored for a long time or used at a high temperature for a long time. Due to oxidation, the content of free bases decreases or the content of free organic acids increases, the dropping point decreases, the appearance color becomes darker, peculiar odor occurs, the consistency and strength limit, similar viscosity decreases, corrosive products are formed and the grease structure is destroyed. Substance, causing soap oil to separate. Therefore, in the long-term storage of lubricating grease, it should be stored in a dry and ventilated environment to prevent sun exposure, and the changes of free alkali or free organic acid, corrosion and other items should be checked regularly to ensure its quality and performance.

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