How to repair the sealing part of the small crane joint


The phenomenon of hydraulic oil leakage from the periphery of the slewing bearing occurred during the operation of the small crane. The oil leakage was not very serious at first. After about half a year of continuous use, the oil leakage became more and more serious, and finally developed to the level of several kilograms of hydraulic oil every day.

The slewing bearing part of the crane is a closed structure for getting on and off, and the leakage point cannot be directly observed. After eliminating the possibility of oil leakage from each pipe joint, the problem is concentrated on the rotary reducer and the central rotary joint.

If the shaft end seal of the rotary motor and the output shaft end of the reversing reducer leak, or the central rotary joint leaks oil, the annular groove formed by the slewing bearing and the lowering channel of the small crane may be filled with hydraulic oil.

Eventually, oil leaks from the joint gap between the slewing bearing and the upper vehicle.

Check the lubricating oil in the rotary reducer first, and there is no increase or decrease. After explaining the fault location, remove the central rotary joint.

After disintegration, it was found that the uppermost sealing part was corroded and worn. After testing, the depth of wear reached 0.4~0.5mm, and the appearance was uneven, which could not guarantee normal sealing.

If the central rotary joint assembly of the small crane is replaced, the economic cost is obviously high. After research, it is decided to adopt a concise and feasible correction plan.

Press the worn part of the core of the central rotary joint to the car, and process another inlaid sleeve to weld it. When welding, ensure that the welding seam is tightly sealed and no leakage occurs.

Grind the surface of the sealing part of the inlaid sleeve to the original size. In order to meet the surface hardness and anti-corrosion requirements, it is best to chrome-plated after fine grinding.

Replace all worn seals during installation. Test the machine after installation, and the oil leakage is eliminated.