Handrail belt drive shaft repair must be performed according to standardized procedures. Core techniques include safe disassembly, precise replacement, troubleshooting, and testing/adjustment. Specific steps are as follows:
Disassembly and Replacement Procedure
Safety Preparation: Turn off the escalator power, hang warning signs, and ensure the operating environment is free of electrical hazards.
Component Removal:
Remove the upper comb plate, lower comb plate, and steps/treads to create operating space;
Remove the inner and outer cover plates of the handrail belt and guide wheels to expose the drive shaft;
Use a wrench to loosen the drive bearing fasteners (such as bolts and nuts), and gently remove the drive shaft, avoiding forced prying that could deform the shaft.
Parts Inspection and Replacement:
Inspect the drive shaft surface for wear, cracks, and damage to bearings, gears, and other accessories;
If the bearing inner ring is loose and the journal is loose, or if the gear teeth are pitted, replace them simultaneously;
When installing a new drive shaft, compare its specifications (diameter, length, material) with the original shaft to ensure it matches the escalator model.
Reassembly: Align the new drive shaft with the mounting hole, slowly push it in until positioned, and tighten the fasteners.
Reinstall the guide wheels, cover plate, and steps/pedals in sequence to restore the escalator's structural integrity.
Drive Shaft Fault Related Handling: Handrail Belt Elongation Adjustment: If the handrail belt elongates due to a drive shaft problem, use the adjustment mechanism at the bottom of the escalator (such as a tensioning screw) to absorb the excess length and prevent slippage between the handrail belt and the drive shaft.
When replacing damaged bearings, prioritize bearings of the same model as the original (such as 6204-2RS deep groove ball bearings) to ensure radial clearance meets the standard (0.05-0.1mm).
Operational Abnormality Repair: A hissing sound at the curved end may indicate improper drive chain tension. Adjust the linear pressure belt spring (pressure 0.5-1.0kN) or the curved pressure belt slack (gap 2-3mm).
An overly tight drive chain will accelerate bearing wear, while an overly loose chain will cause tooth skipping. Use a tension gauge to measure and adjust to the specified value.
Testing and Adjustment Points
Trial Run Inspection: After powering on, run the escalator unloaded for 10-15 minutes and observe the synchronization between the handrail belt and the drive shaft.
Listen for abnormal sounds (such as metallic friction sounds or periodic impact sounds) and check the vibration amplitude (≤2mm/s²).
Dynamic Adjustment: If the handrail belt is misaligned, correct it by adjusting the guide wheel angle (±5°) or the drive shaft level (≤0.1mm/m).
If fasteners are loose, retighten them using a torque wrench to the standard value (e.g., 50-60 N·m for M12 bolts).
After maintenance, record the drive shaft replacement time, bearing model, and adjustment parameters. Regularly check the lubrication status (using lithium-based grease) every 3 months to extend component life.