Abstract:In order to test the durability of rotary joints, a constitution scheme of the full automatic durability test system was studied out. By using automatic doubleacting pressurized cylinders at a hydraulic loading section of the test system, the circuit working pressure was up to 42 MPa. A servo motor was decelerated by a planetary reducer to drive the rotary shaft of rotary joint and the rotation of the case relatively. Automatically adjusting the speed of rotary joint, steering and angle were implemented, with the benefits of a compact structure, small volume and smooth operation. The gain and loss of electricity in electromagnetic vale, rotate speed of the servo motor, steering and angle were controlled by the program logic controller (PLC). The data of oil temperature, flow, pressure, driven torque and speed of the rotary joint were collected and displayed on a computer, allowing for the generation of curves of changs in pressure, flow and temperature. Thereby it is the first time in our country where automatic detection of the rotary joint performance parameters and realtime display has been achieved.