Bearing lubrication:- We know, Friction is always present in the moving parts of the machine so we should minimize the friction by lubricating the bearings. Lubrication provides a thin film between the contact areas of bearing to reduce friction, dissipate heat and reduce the corrosion of balls and raceways. The bearings are lubricated by using oil or grease. Oil is used in such cases where speed and temperature are high. At high temperatures, oil can be circulated in the bearings to cool the unit. Oil is subjected to evaporation loss after taking the heat from bearings. Grease is preferred where speed is moderate and the temperature is not excessively high. Grease is made up of oil and thickener. It has 85% oil and 15% of thickener. Grease tends to create resistance in the rotating part because it has higher viscosity as compared with oil. If we are doing over greasing of bearings, it causes more resistance in the unit and increases the temperature of bearing. Due to the increased temperature of grease, the thickeners and oil get separated and grease life also decreases, so it is important to grease bearings properly.
Ok, now we will see the care to be taken of a bearing.
1.Bearing should be placed horizontally in a clean and dry environment. The atmospheric dirt or foreign particles should not enter in the bearings, otherwise, it would damage the balls or raceways and causes to bearing failure.
2.Never heat a bearing using direct flame. Heating a bearing above its permitted temperature causes the bearing to fail. Overheating of bearing results in reducing load carrying capacity and leading to eventual failure.
3.Proper lubrication is very important if we want to use bearings for a long time. The proper lubricant must be used as per temperature, load, and speed.
4.Always use proper tools for mounting and dismounting the bearings. Different types of bearing pullers, bearing fitting tool kits and induction heaters are available in the market. Never use the hammer for bearing fitting.
Now at the last, we will discuss the meaning of bearing number and we will finish this video.
Every bearing has its own unique number. This number has a meaning. Let us take an example of 6307 bearing. The first digit indicates the type of bearing. 6 means it is a single row deep groove ball bearing. The second digit indicates a series of bearing. Here, in our example, this is a series 3 bearing. Bearing series tells about the toughness of bearing. Series 3 means it has medium toughness. And the last two digits of bearing number indicates the bore size or internal diameter of bearing. In this case, the last two digits are 0 and 7. It means the bore diameter is not 7mm. But if we multiply 07 by 5 then we will get the bore size, means, 6307 bearing has 35 mm bore size. Remember if we multiply the last two digits by 5 then we will get the bore diameter of bearing. If the bearing number is 6208 then the bearing has 08X05 which equals 40mm of internal diameter.
Thanks and regards,
Basic Engineering
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