Reasons for leakage of hydraulic rotary joints

Hydraulic rotary joints are suitable for high torque working environments and are widely used in industries such as machine tool fixtures, automation, metallurgy, wind power, and construction machinery. Because of its high pressure, it is usually called a high-pressure rotary joint, and some special equipment can reach a maximum pressure of 45MPa.
The most concerning issue during the use of hydraulic rotary joints is the occurrence of leaks, which cannot maintain pressure and cause the equipment to malfunction. It has been found that a relatively large proportion of leaks are caused by internal wear of the rotating joint.

1. Bearing lubrication failure
Some hydraulic slip rings have relatively high rotational speeds and usually come with rolling bearings. After a long period of use of the joint, the lubricating grease in the bearing is insufficient, and the grease is not injected for a long time, resulting in the failure of bearing lubrication, causing dry friction between the rotating shaft and the housing of the rotating joint, which will inevitably accelerate the wear of the rotating joint.
2. The cleanliness of the components does not meet the standard
The hydraulic system where the hydraulic rotary joint is located requires high cleanliness. If the cleanliness is not up to standard, impurities can enter the interior of the rotary joint, damage the sealing surface, accelerate the wear of the sealing surface, and quickly cause damage to the rotary joint. Many industries connect hydraulic rotary joints to key hydraulic components such as hydraulic valves or motors. If the cleanliness of the hydraulic system is not up to standard, it may even damage these hydraulic components. Causing greater losses to the user unit.
3. Poor concentricity with the device
The coaxiality difference between the hydraulic rotary joint and the shaft head of the connecting equipment results in eccentricity. In this way, during the rotation process of the rotary joint, different parts of the rotor are subjected to uneven forces, which accelerates the wear of the rotating shaft. Severe wear and tear can lead to leakage of the rotary joint.
From the above, it can be seen that neglecting some details during use can lead to leakage. The general recommendation is to install a filter screen or other dust removal facilities before entering the oil circuit to prevent impurities from entering; Strictly follow the operating conditions of the equipment, select suitable operating conditions such as pressure, temperature, and speed, and do not blindly select; In addition, in order to effectively extend the service life, maintenance and upkeep should be carried out, and lubricating oil should be regularly added or bearings replaced according to the manufacturer’s requirements. Finally, hydraulic rotary joints may experience wear or deformation, resulting in leakage faults. The common problem is that the sealing surface wears out due to friction, and the sealing ring deforms due to long-term wear or aging, which can cause leakage in hydraulic rotary joints. Therefore, it is necessary to regularly inspect vulnerable parts. For slight wear on the sealing surface, it should be promptly returned to the manufacturer for repair. For severe wear, new vulnerable parts should be considered for replacement, and in severe cases, replacement is necessary.