Failure Analysis of NTN Bearing on Transmission

Writer: Eric Bearing Limited

The fault phenomenon of the NTN bearing on the transmission: the noise of the transmission gear meshing, the operation noise of the NTN bearing is too loud; the transmission makes abnormal noises such as dry grinding impact.

NTN bearing failure reason:

Rolling NTN bearing lacks oil (such as the first shaft front NTN bearing), the steel ball mill loses roundness, the raceway has pitting, delamination, and scratches. The inner and outer raceways rotate on the shaft or in the housing, or the NTN bearing clearance is too large. The elimination method is: add oil and replace damaged NTN bearings;

Gear machining accuracy or improper heat treatment process causes gear sway or tooth shape change. The elimination method is: replace the damaged gear;

Tooth gap is too large or the spline fit gap is too large. The elimination method is: replace the damaged synchronizer hub and shaft;

The repaired tooth surface is not trimmed with burrs, bumps, etc. The elimination method is: repair tooth surface;

The tooth surface is peeled off, delaminated, damaged, worn or even repaired. The gears are not replaced in pairs. The elimination method is: replace the damaged gear;

The first axis and the second axis are bent and deformed. The elimination method is: replace the deformed shaft;

After repairing the NTN bearing hole boring bushing in the shell, the center distance between the two holes will change or the two axes will not be parallel. The elimination method is: replace the damaged shell;

After the repair, the shift fork is not right or the single side surfacing is too thick after the shift fork is worn, which makes the position of the related gears inaccurate. The elimination method is: replace the fork;

The fastening nut of the second shaft is loose or the axial positioning of other shafts is out of alignment. The method of elimination is: reassembly;

The groove of the self-locking device, the steel ball is worn too much, or the self-locking spring is fatigued or broken, causing the off-position when the gear is shifted. The elimination method is: replace the fork shaft, steel ball or spring;  If you are looking for NTN bearings , ERIC BEARING LTD can supply , pls click here . 

 

Individual gear teeth are broken. The elimination method is: replace the damaged gear;

The gear oil is insufficient, deteriorated, the specifications do not meet the requirements, or there is debris in the oil. The exclusion method is: add or replace the oil that meets the requirements.

1.The capacity of NTN bearing to bear load is much smaller than the sliding NTN bearing of the same volume, therefore, the radial size of NTN bearing is large. Therefore, in the occasions of high load and the requirements of small radial size and compact structure (such as internal combustion engine crankshaft NTN bearings), sliding NTN bearings are mostly used;

2.NTN bearings are relatively vibrating and noisy, especially in the later stages of use.Therefore, NTN bearings are difficult to handle in situations where high precision is required and vibration is not allowed.Generally, sliding NTN bearings are better.

3.NTN bearings are particularly sensitive to foreign objects such as metal shavings. Once foreign objects enter the NTN bearings, intermittently large vibrations and noises will occur, which will also cause early damage. In addition, NTN bearings are also prone to early damage due to impurities such as metal clamps. Even if there is no early damage, the service life of NTN bearings has a certain limit. In short, the service life of NTN bearings is shorter than that of sliding NTN bearings.

However, compared with sliding NTN bearings, NTN bearings have their own advantages and disadvantages, and each occupies a certain application occasion. Therefore, the two cannot completely replace each other.

However, due to the outstanding advantages of NTN bearings, at present, NTN bearings have developed into mechanical The main support type is more and more widely used.