Answers to Common Questions About INA Bearing Installation

Writer: Eric Bearing Limited

Question 1:How to choose grease?

Lubrication has a very important effect on the operation and life of INA bearings. Here is a brief introduction to the general principles of grease selection. Lubricating grease is made of base oil, thickener and additives. The performance of different types and different types of lubricating grease of the same type is very different. The allowable rotation limit is different. Please pay attention when choosing. The performance of the grease is mainly determined by the base oil. Generally, low viscosity base oil is suitable for low temperature and high speed, and high viscosity is suitable for high temperature and high load. Thickener is also related to lubricating performance. The water resistance of the thickener determines the water resistance of the grease. In principle, greases of different brands cannot be mixed, and even greases of the same thickener can have bad effects on each other due to different additives.

Question 2:Must the bearings be cleaned before installation? 　

The bearing surface is coated with anti-rust oil, you must carefully clean with clean gasoline or kerosene, and then apply clean high-quality or high-speed high-temperature lubricating grease before installation and use. The effect of cleanliness on rolling bearing life and vibration noise is very large. But we have to remind you in particular that the fully enclosed bearings do not need to be cleaned and refueled.

Question 3:How to install and disassemble?

Do not directly hammer the INA bearing end face and non-stressed surface during installation. Use a pressure block, sleeve or other installation tools (tooling) to make the bearing evenly stressed, and do not install it through the driving force of the rolling element. If the installation surface is coated with lubricating oil, the installation will be smoother. If the interference is large, the bearing should be placed in mineral oil and heated to 80~90℃ as soon as possible. The oil temperature should be strictly controlled not to exceed 100℃ to prevent the tempering effect from reducing the hardness and affecting the size recovery. When it is difficult to disassemble, it is recommended that you use the disassembly tool to pull out and carefully spray hot oil on the inner ring. The heat will expand the inner ring of the rolling bearing, making it easier to fall off.

Question 4:Are the requirements on the installation surface and installation site?

Yes. If foreign materials such as iron filings, burrs, and dust enter the INA bearing, it will cause noise and vibration during the operation of the bearing, and may even damage the raceway and rolling elements. Therefore, before installing the bearing, you must ensure that the installation surface and the installation environment are clean.

Question 5:When lubricating bearings, the more grease applied, the better?

When lubricating INA bearings, the more grease is applied, the better. This is a common misconception. Excessive grease in the bearing and bearing chamber will cause excessive stirring of the grease, resulting in extremely high temperatures. The quantity of rolling bearing filled with lubricant should be filled with 1/2 to 1/3 of the internal space of the bearing, and should be reduced to 1/3 at high speed.

Question 6:The smaller the radial clearance of the bearing, the better?

Not all INA bearings require a minimum working clearance, you must choose the appropriate clearance according to the conditions. In the national standard 4604-93, the radial clearance of rolling bearings is divided into five groups -2 groups, 0 groups, 3 groups, 4 groups, and 5 groups. The clearance values ​​are in order from small to large, and group 0 is the standard clearance. The basic radial clearance group is suitable for general operating conditions, normal temperatures and commonly used interference fits; for rolling bearings working under special conditions such as high temperature, high speed, low noise and low friction, it is better to use large radial clearance; Bearings for precision spindles, machine tool spindles, etc. should use a small radial clearance; for roller bearings, a small amount of working clearance can be maintained. In addition, there is no clearance for separate bearings; finally, the working clearance after the bearing is installed is smaller than the original clearance before installation, because the bearing must withstand a certain load of rotation, and there are INA bearing coordination and load. The amount of elastic deformation.

After the bearing installation is completed, in order to check whether the installation is correct, a running inspection is required. Small machinery can be rotated by hand to confirm whether it rotates smoothly. The inspection items include poor operation due to foreign objects, scratches, and indentations, unstable torque due to poor installation, poor processing of the mounting seat, excessive torque due to too small clearance, installation errors, and seal friction, etc. Wait. If there is no abnormality, power operation can be started.

The power operation starts from the no-load low speed and gradually increases to the rated operation under the specified conditions. The items to be checked during the trial operation are whether there are abnormal sounds, changes in INA bearing temperature, leakage or discoloration of lubricant, etc. If an abnormality is found, the operation should be stopped immediately, the machine should be inspected, and the bearing should be removed for inspection if necessary. INA RAE30-NPP bearings online , pls click here : 

Bearing temperature can generally be estimated based on the external temperature of the bearing housing. However, it is more accurate to use the oil hole to directly measure the temperature of the outer ring of the bearing. The rolling bearing temperature gradually increases from the beginning of operation, and the temperature is usually stable after 1 to 2 hours. If the bearings are not properly installed, the temperature will rise sharply and abnormally high temperatures will appear. The reasons are too much lubricant, INA bearing clearance is too small, poor installation, excessive friction of the sealing device, etc.

The rotating sound of the INA bearing is checked with a stethoscope, etc. There are strong metal noises, abnormal sounds, irregular sounds, etc., indicating abnormalities. The reasons are poor lubrication, poor precision of the shaft or bearing housing, bearing damage, foreign matter intrusion, etc.