Assembly Technology of NTN Bearing Inner Ring

Writer: Eric Bearing Limited

1. The shaft shoulder of the bearing is fixed

NTN bearing inner ring relies on shaft shoulder and interference to achieve axial fixation. Suitable for supporting structures with fixed ends. The structure is simple and the outline size is small.

2. The elastic ring of the bearing is fixed

The inner ring of the bearing is axially fixed by the shaft shoulder and the lock nut. Can bear small bidirectional axial load. The axial structure size is small.

3. The lock nut of the bearing is fixed

The inner ring of the NTN bearing is axially fixed by the shaft shoulder and the lock nut. And it has anti-loosening stop washers, safe and reliable, suitable for high speed and heavy load occasions.

4. The bearing end thrust washer is fixed

The inner ring of the NTN bearing is axially fixed by the shaft shoulder and the shaft end retaining ring. The shaft end retaining ring is fixed to the shaft end with screws. The fixing screw should have anti-loosening device.

It is suitable for occasions where the shaft end is not suitable for thread cutting or space is limited.

5. The bearing sleeve is fixed

Relying on the radial size of the inner hole of the adapter sleeve is compressed and clamped on the shaft to achieve the axial fixation of the inner ring of the bearing.

6. The bearing's withdrawal sleeve is fixed

The clamping method of the withdrawal sleeve is the same as that of the adapter sleeve. However, due to the special nut, the withdrawal sleeve is easy to install and remove. It is suitable for the fixation of the double-row spherical bearing on the optical axis with large radial load and small axial load.

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Bearing assembly process

The ground parts are stored in the assembly library after passing the inspection. If the production is properly organized, the parts can also be directly entered into the assembly room for sorting and assembly. The bearings are not stored in the warehouse, and the NTN bearings reduce the production cycle. The assembly librarian must not only keep the bearing parts well, but also grasp the status of the ring rolling tolerance and rolling element tolerance. Make good statistics, issue parts tolerance order form, organize supplementary parts, so as to assemble the assembly process.

For small batch suction production. Especially in the case of large dispersion of rolling element and raceway size, the bearing is often organized by grinding a ferrule and sorting the dimensional tolerance of the ferrule first, and then the size of the rolling element In the deviation state, the deviation range of the raceway size grinding of the other ring of the bearing is formulated to obtain a higher ratio of the sleeve. Under normal circumstances, the final grinding outer raceway is close to the final process of the outer ring grinding process, and the customized tolerance is better placed on the outer ring.

Analysis of the importance of lubrication of NTN bearings after installation

(1) When cleaning a large number of NTN bearings, first use hot engine oil with a temperature of 90 to 100 degrees Celsius to drench the package oil, at the same time dig out all the old oil with a seamless and non-chip tool, and then drench it for a few minutes. Then rinse off the engine oil with kerosene, and finally clean it again with gasoline. After cleaning, wear film gloves and put the bearing on a clean cloth or paper on the work table to dry.

(2) Before the NTN bearing is installed, the processing quality of the shaft and the seat hole and related parts (such as dimensional accuracy, shape accuracy and surface roughness, etc.) should be checked according to the technical requirements on the design drawings using appropriate measuring tools.

(3) Open the bearing package at the time of installation, immerse it in the above-mentioned gasoline and other liquids and slowly turn it by hand, to ensure that the packaging oil on the surface of the cage, rolling elements and raceway is thoroughly cleaned.

(4) The assembly surface should be cleaned with clean gasoline, kerosene, toluene or xylene solutions, and dried with a clean rag, and then coated with a thin layer of lubricating oil, so that the installation operation is more convenient.

(5) Note that bearings with seals cannot be cleaned by this method, and the inside of the seal should be kept as it is and cannot be cleaned.

(6) If there are bruises, burrs, rust spots or solid particles (such as abrasive debris, sand, mud) on the assembly surface of the shaft and bearing housing holes, not only will the bearing installation be difficult and the installation position is incorrect, but also solid If the particles fall into the bearing, they will be abrasive. When the bearing rotates, it will abrade or scratch the working surface of the bearing, so it must be carefully checked before installation. If any of the above defects are found, they should be corrected.

For example, use an oil file to remove burrs, bumps, rust spots, and polish with a fine emery cloth, such as cleaning solid particles and dirt.

The influence of lubrication on the performance of NTN bearings can be divided into the following aspects:

1. The first is to lubricate the various parts of the bearing to reduce the friction and wear of the bearing;

2. Make the rolling contact surface of the bearing often form an appropriate oil film to extend the fatigue life of the bearing;

3. The heat generated inside the bearing due to friction or other reasons is taken away by lubrication;

4. Lubrication can achieve anti-rust and dust-proof effect on the bearing.

The two main lubrication methods of NTN bearings are grease lubrication and oil lubrication

Grease lubrication has a sealing method in which sealed bearings are filled with grease in advance, and a proper amount of grease is filled in the inside of the housing and refilled or replaced at regular intervals. In addition, for machines with multiple NTN bearings that require lubrication, a centralized grease supply method with pipes connected to each lubrication point is also used.

Grease lubrication can achieve a long time without replenishing after filling grease, and the structure of its sealing device is relatively simple, so it is widely used. Oil lubrication is relatively simple. Regular lubrication can increase the service life of bearings.