The vibration value does not exceed the standard, but there is obvious shaking phenomenon in the gearbox body. What is the reason for this

1. Structural resonance and box stiffness issues

This is a common hidden factor that leads to "normal values but significant jitter". When the excitation frequency (such as gear meshing frequency) of the reducer during operation approaches the natural frequency of the casing or installation foundation, it will cause structural resonance, leading to a sharp amplification of noise and vibration. In addition, if the installation foundation of the reducer has insufficient dynamic stiffness, or if the box structure design is unreasonable or the rib plate layout is poor, it will weaken the overall rigidity, causing slight vibrations to show obvious shaking sensation on the box.

2. Loose external connections and installation deviations

Minor looseness of external connectors may not cause a significant increase in overall vibration values in the initial stage, but it is sufficient to cause significant shaking in the local area of the box. For example, loose anchor bolts, motor screws, or coupling bolts can cause instability in the supporting structure. At the same time, if the alignment accuracy between the reducer and the drive motor is insufficient (such as coupling alignment error, input/output shaft misalignment), additional radial and axial forces will be generated, causing the box to shake.

3. Early wear and tear of internal mechanical components

In the early stages of gear and bearing failures, the vibration values may not have reached the alarm limit, but physical shaking has already appeared:

Gear problem: Slight wear and pitting on the gear tooth surface, or excessive gear mesh clearance, can cause impact during power transmission, leading to periodic vibrations within a specific speed range.

Bearing issues: Early wear, damaged retainers, or inappropriate clearances inside the bearing can cause uneven rotational resistance and result in regular slight vibrations.

4. Abnormal lubrication system

The condition of lubricating oil directly affects the smoothness of operation. If the lubricating grease ages, dries up, or the filling amount is insufficient, or if the oil circuit/injection hole is blocked, resulting in poor local lubrication, it will increase the frictional resistance between the gear and the bearing, causing joint or transmission components to become stuck and shake during movement.

5. Unbalanced quality and load issues

If the rotating components inside the reducer (such as gears and shafts) have uneven mass distribution due to manufacturing errors, accidental impacts, or uneven wear, they will generate centrifugal force and induce periodic shaking during rotation. In addition, if the working machine load is unbalanced or the gearbox is in an overloaded operating state, it can also cause abnormal shaking of the box.