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How To Test The Rolling Bearings And Coil Springs Of Diesel Generators

Aug. 21, 2023

The rolling bearings used in the internal combustion engine of diesel generators include ball, roller (cone) and needle roller bearings. They are often operated at high speeds and under heavy loads, and after prolonged use, the raceways and rolling elements experience breakage, burnout, cracking, fatigue spalling and black spots. The inspection of rolling bearings is generally not dismantled. Through the appearance inspection after cleaning, the idling test detection and the measurement of the internal clearance if necessary, the quality can be judged whether it is qualified or not.


1. External inspection. When the following damages are found in the rolling bearing, it should be repaired or replaced.

(1) The raceways and rolling elements are discolored due to burnout.

(2) There are hit marks, scratch marks and scratches on the raceway.

(3) There are cracks, delamination, peeling and a lot of black spots on the raceway and rolling elements.

(4) There are penetrating cracks and missing or loose rivets on the isolation ring.

(5) The notch of the roller on the isolation ring is too damaged, and the roller can fall out in vain.

(6) The end face of the ball bearing isolation ring is damaged, and the depth exceeds 0.3mm.

(7) The tapered ball is damaged, and the small end working face protrudes from the end face of the outer race of the bearing.

(8) Gap on the inner end face of the big end of the tapered roller bearing and metal spalling.


After external inspection of the rolling bearing, if it is found that there are slight corrosive black spots on the bearing and slight defects of the spacer ring without interfering with the rotation of the bearing, and that the circumference of the small end flange surface of the inner ring of the roller cone bearing has no more than four broken notches. The total radian is not more than 30, and there is a certain distance between the two adjacent gaps (not less than 30 degrees), etc., it can generally continue to be used.


600KW Shangchai Power Generator Set

2. Idling test detection. Rotate the bearing to see if the bearing spins freely, is noisy, stalls and seizes. The uneven rotation of the bearing can be judged from the feeling in the hand.


3. Gap measurement. The damage of the ball bearing can be judged by measuring its radial clearance and axial clearance. Clamp the inner ring of the bearing with one hand, and push the outer ring with the other hand to check the radial clearance of the ball bearing of the diesel generator. The value of the needle change is the bearing radial clearance, when detecting the bearing axial clearance, the inner race should be pushed up and down. The maximum and minimum values of the hands are the axial clearance of the bearing.


When using a diesel generator coil spring, due to thermal annealing or fatigue, residual deformation will occur, weaken the elasticity, and damage the free length change, deformation and fracture of the spring. The free length of the spring can be measured with a ruler or a vernier caliper, or a new spring can be used for comparison and verification. The inspection methods for diesel generator coil springs and other parts are as follows:


Since the change of spring elasticity follows Hooke's law, when testing the elasticity of the spring, the spring should be compressed to a certain length to observe whether the elasticity meets the requirements. If the load is lower than the specified value, the elasticity of the spring does not meet the requirements. Whether the spring is broken is generally judged by just inspection. Whether the spring is skewed, it can be detected with a square ruler, and it should be replaced if the skew exceeds 2 degrees. The rotation plane of the disc-shaped part needs to measure the runout of the end face. Rotate part 1, the reading on the differential meter is the amount of runout. The radius of the measuring point has a great influence on the beating. Therefore, different measuring point radii are stipulated for different parts in inspection technology. For rod-shaped parts (such as connecting rods, etc.) and parts with special shapes such as I-beams and frames, inspections such as deformation and breakage should be carried out, which will be discussed in related articles later.


In addition, for special bolts, studs, nuts and washers, etc., the technical status can be judged by inspection method. Bolts and studs should not be bent or elongated, and the threaded part should not be flattened, ground, or slipped. Flat washers and lock washers should be flat and free of cracks, and spring washers should not lose elasticity.


Guangxi Dingbo Generator Set Manufacturing Co.,Ltd. is one of the earliest manufacturers of generators and diesel generator sets in China. The company was established in 2006 and the company occupies an area. It has service departments across the country to provide users with one-stop service of design, supply, debugging and maintenance at any time. Welcome customers to come to consult and visit. Looking forward to your inquiry, please send email to us for details sales@dieselgeneratortech.com

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