Common Problems and Treatment of Gearbox (Part 1)

Gear box abnormal sound

1 There is knocking on the gear tooth surface causing noise

Situation: This problem is mainly reflected in the test stand of the assembly plant of the complete machine manufacturer. The characteristics of this kind of abnormal sound: the sound frequency is stable, there is abnormal noise in one direction, and there is no abnormal noise in reverse rotation. You can calculate the speed and abnormality of the low-speed shaft by calculating the Frequency relationship to determine the specific location of the abnormal sound.

Reason: bumps occurred during the assembly process. Due to flaws in the company's test quality control, such problems may occur in a very small number of gearboxes.

Treatment: According to the analysis results, carefully search for the bruises on the tooth surface of the relevant gear. When searching, the oil on the tooth surface should be wiped clean to avoid affecting the feel. The bruises mainly exist on the top and sides of the tooth profile.

2 Abnormal noise caused by excessive gear pitch error

Situation: This problem is also reflected in the assembly plant of the complete machine manufacturer. The characteristics of this kind of abnormal sound: the frequency of the sound is stable, and the two-way rotation is abnormal.

Reason: The abnormal noise caused by the excessive change of the adjacent tooth cycle caused by gear processing. The gear test report of the problem gear can be found through the speed ratio relationship.

Treatment: Except for the high-speed shaft that can be taken out, it cannot be handled on-site, and can only be returned to the company for replacement and repair.

3 Abnormal noise of friction interference

Situation: There is a high probability of the problem appearing in the repair shop. The reason for the wind field is generally the interference of the oil rejection ring and the end cover, which is accompanied by abnormal heating phenomena in the relevant parts.

Treatment: Identify the components that interfere with friction, rework, or tighten the parts.

4 Abnormal noise caused by bearing problems

Situation: When the noise is a hum and the frequency is relatively fast, the tooth surface inspection is normal, and the speed ratio relationship is used to calculate that it is not a gear problem, then it is most likely that there is a problem with the bearing.

Cause: The dents on the inner raceway or roller surface of the bearing will cause the bearing to run unsteadily and cause abnormal noise.

Treatment: Carefully check the bearing raceways and rollers and find that there is a problem to replace the bearing.

Gear box

5 Abnormal noise caused by long-term parking corrosion

Situation: One tooth on each of the two gears of a pair of gear pairs has long strips of rust marks, and the remaining teeth are intact.

Reason: The gearbox is parked for a long time, which causes the tooth surface to rust, and the unstable operation produces abnormal noise.

Treatment: The rust can not be completely eliminated, it can only be polished with a whetstone, and then followed up.

6 Abnormal noise caused by non-gearbox itself

Situation: The noise appears near the low-speed end spindle or the high-speed end brake disc. After checking that the parts of the gearbox are intact, there is still an abnormal noise, or the frequency of the noise is not directly proportional to the speed.

Reason: The low-speed end may be a problem with the hub or the main shaft bearing, and the high-speed section may be caused by the coupling or the motor to find the correct deviation.

Remedy: After repeatedly searching the cast iron gear box and confirming that there is no problem with the gearbox, it can be judged that there is a problem with other parts, and you can ask the machine manufacturer to search for the parts that may have problems.