Solar Pile Driver Rotary Mechanism: Common Faults and Troubleshooting

The rotary mechanism of a solar pile driver is mounted on the pressurizing carriage and consists of a rotary motor, rotary gearbox, and other components. According to statistical data, faults in the rotary mechanism account for approximately 30% of all drilling rig failures. Moreover, the rotary mechanism has a complex structure with high technical specifications and precision requirements, which increases the difficulty of repair work.

Common Faults and Diagnosis

1. Bearing Breakage

The rotary mechanism of the photovoltaic pile driver is equipped with eight sets of bearings. Bearing breakage accounts for over 70% of rotary mechanism failures.

The main causes of bearing breakage are poor lubrication and poor bearing material quality. This is particularly true for the four bearings installed at the upper end of the gearbox. If the gears inside the gearbox cannot splash lubricating oil in time to provide adequate lubrication, the probability of breakage increases significantly—especially during cold winter conditions. Additionally, breakage of the 9069434 tapered thrust bearing installed at the lower end of the hollow shaft of the rotary mechanism is mainly caused by excessive axial pressure and intense vibration.

2. Water Ingress into the Gearbox

This fault is primarily caused by excessive wear of the waterproof sealing ring (static ring) installed at the upper end of the main shaft. Water then enters the gearbox through the bearing clearance along the hollow shaft, causing the lubricating oil to deteriorate and leading to corrosion on the bearing surfaces.

3. Oil Leakage from the Rotary Gearbox

There are two causes of oil leakage from the rotary gearbox. One is wear or installation damage to the oil-resistant sealing ring at the lower part of the main shaft; the other is loosening of the screws that secure the sealing ring housing. Oil leakage not only results in unnecessary waste but also lowers the oil level inside the gearbox, affecting the service life of the bearings and gears inside.

Troubleshooting

1. Addressing Bearing Breakage

After bearings in the rotary gearbox break, while replacing the bearings, it is essential to carefully inspect and clean the gearbox to remove metal debris generated by bearing or gear wear. When replacing bearings at the upper end of the gearbox, an appropriate amount of lubricating oil should be pre-applied to the bearings to prevent damage to the bearing surfaces during initial operation before the oil inside the gearbox begins splashing, which could affect service life. This is especially important for the 9069326 tapered bearing located at the upper end of the hollow shaft. Because it is blocked by the 3003126 double-row bearing installed below it, the oil in the gearbox can hardly lubricate it, making it more prone to failure. Therefore, pre-lubrication during installation is necessary.

When replacing the four bearings on the main shaft, the main shaft must be withdrawn from the gearbox. During the process of withdrawing and reinserting the shaft, care must be taken to protect the threads at the upper end of the hollow shaft.

2. Addressing Water Ingress into the Gearbox

If water enters the rotary gearbox, stop operation immediately. Remove the air connection joint at the top of the hollow shaft, inspect and replace the waterproof sealing ring and the 100x5mm O-ring fitted on the shaft, and check the tension of the pressure spring. Drain all waste oil and water from the gearbox, then refill with lubricating oil before resuming operation.

3. Addressing Oil Leakage from the Rotary Gearbox

For oil leakage from the rotary gearbox, appropriate corrective measures should be taken based on the leakage location. If oil leaks from the lower end of the hollow shaft, the rotary joint and drill pipe at the lower end of the hollow shaft must be disconnected, the sealing ring housing fitted over the lower end of the hollow shaft removed, and the sealing ring replaced. At the same time, check whether the surface of the hollow shaft is smooth to prevent the sealing ring from being damaged again. When installing the sealing housing at the lower end of the hollow shaft, it is recommended to roll a thin copper sheet inside the sealing ring to form a flared opening slightly larger than the diameter of the hollow shaft. After inserting the shaft, remove the copper sheet—this helps protect the sealing ring from damage.