Abnormal vibrations in excavators not only affect the comfort of operators but can also lead to premature fatigue and ageing of components over time, resulting in unnecessary losses. What are the causes of abnormal vibrations in excavators, and how can they be addressed?

1. Engine vibration

The engine is the primary source of vibration in an excavator. Excavator engines typically have large displacement, and normal operation generates significant vibration. Therefore, the engine and chassis are connected via a flexible coupling. Under the influence of the vibration damping mechanism, the vibration transmitted from the engine to the chassis is greatly reduced, keeping chassis vibration within reasonable limits.

If the mounting bolts of the engine mount pads are loose or the buffer blocks are fatigued and damaged, the connection between the engine and the machine body becomes loose, and the buffer mechanism loses its function. This causes the engine to shake violently during operation, leading to abnormal vibration of the excavator's machine body.

Solution: Tighten the mounting bolts or replace the buffer blocks.

2. Rotation Mechanism Vibration

If vibration, stuttering, and a ‘clunking’ sound occur when the upper structure rotates, it can be determined that the rotation mechanism is malfunctioning. Since the excavator's rotation mechanism is primarily composed of a set of planetary gear sets, if there are contaminants between the gears or the gears are excessively worn, abnormal meshing between the gears will cause the entire gear set to operate inefficiently, ultimately resulting in abnormal vibration during upper structure rotation.

Solution: Inspect and clean any contaminants from the planetary gear set. If any gears are damaged, replace them promptly.

3. Boom Vibration

If abnormal vibrations occur during the lifting or lowering of the boom, and the movement is not smooth, it is generally determined that the hydraulic system is malfunctioning. Abnormal wear of the one-way valve in the boom hydraulic cylinder or contaminants in the hydraulic oil can cause the valve core to switch improperly, resulting in discontinuous hydraulic oil flow, causing the hydraulic cylinder to operate jerkily, and ultimately leading to abnormal vibrations in the boom.

Solution: Inspect and clean the one-way valve in the hydraulic cylinder. If the one-way valve is excessively worn, replace it promptly.

4. Cab Vibration

Abnormal vibrations in the cab are the most noticeable to the operator. When the screws connecting the cab to the machine body become loose, the cab will shake more than the machine body. Due to resonance principles, when the engine is at a specific RPM, the cab vibrations become particularly intense.

Solution: Inspect and tighten the mounting screws of the cab base.

5. Hydraulic Pump Vibration

Vibration from the hydraulic main pump can also cause abnormal vibration throughout the machine. Hydraulic pump vibration is primarily caused by irregular fluid flow within the pump. Since the hydraulic pump generates high-pressure oil, any fluctuations in the fluid flow will inevitably cause pump body vibration. If gas is mixed into the fluid, causing cavitation, or if the fluid contains excessive iron particles or other contaminants, or if the piston is excessively worn, leading to poor piston operation, these factors can all cause pump body vibration. Additionally, blockages in the hydraulic pump's oil supply lines or insufficient oil supply to the pump body can also cause vibration.

Solution: Inspect the internal components of the pump body for normal operation, replace the hydraulic oil with clean oil, and ensure the sealing performance of the hydraulic system.