The stable operation of the oil drilling rigs cardan shaft is inseparable from the reliable support of its internal key components. As a core component that transmits high torque and adapts to extreme working conditions, the quality and performance of key components of the cardan shaft, such as flange yokes, cross shafts, needle bearings, and spline pairs, directly determine the service life and operational stability of the cardan shaft, and even affect the safety of the entire oil drilling operation. Under the high-frequency impact, continuous heavy load, and complex corrosive environment of drilling operations, the wear of key components is inevitable. Therefore, strengthening the reliability improvement and full-process quality control of key components has become the core focus to ensure the long-term stable operation of the cardan shaft.
As the core force-bearing component of the cardan shaft, the cross shaft is the top priority for reliability improvement. During drilling operations, the cross shaft has to bear frequent impact loads and alternating torques, which is prone to failures such as wear, cracks, and fractures, leading to the failure of the cardan shaft. To improve the reliability of the cross shaft, domestic enterprises have continuously optimized material selection and processing technology, abandoning traditional ordinary alloy steel and adopting high-strength low-phosphorus alloy structural steel. After multiple heat treatment processes such as carburizing and quenching, and low-temperature tempering, the surface hardness of the cross shaft reaches HRC58-62, and the core hardness is maintained at HRC30-35, which not only ensures excellent wear resistance and fatigue resistance but also has good toughness, effectively resisting the impact load during drilling. At the same time, strict control is exercised over the processing accuracy of the cross shaft, and CNC grinding technology is adopted to ensure that the roundness and cylindricity errors of the cross shaft journal are controlled within 0.005mm, reducing wear during operation and extending the service life.
As key transmission components of the cardan shaft, the fit accuracy and sealing performance of needle bearings and spline pairs directly affect the power transmission efficiency and operational stability. The needle bearing undertakes the rotational support role between the cross shaft and the universal joint fork, and is prone to wear, jamming and other problems due to insufficient lubrication and impurity intrusion. To address this pain point, enterprises adopt high-precision needle bearings, made of high-quality bearing steel, which are subjected to precision grinding and surface strengthening treatment to improve the bearing capacity and wear resistance of the bearing; at the same time, the bearing sealing structure is optimized, adopting a double-lip seal design with high-temperature and wear-resistant sealing materials to effectively prevent lubricating grease leakage and external impurity intrusion, ensuring long-term stable operation of the bearing. The spline pair adopts an involute spline design, optimizing tooth profile parameters to improve tooth surface contact accuracy, reducing impact and vibration during transmission. At the same time, surface phosphating treatment is adopted to enhance the wear resistance and corrosion resistance of the spline pair, avoiding power transmission loss caused by spline wear.
Full-process quality control is an important guarantee for the reliability of key components, which needs to run through the entire links of design, production, testing, and assembly. In the design stage, finite element analysis, simulation and other technologies are used to optimize the structure of key components, reduce stress concentration, and improve the bearing capacity of components; in the production stage, the quality of raw material procurement is strictly controlled, and strict chemical composition testing and mechanical performance testing are carried out on raw materials such as steel and bearings, and unqualified raw materials are strictly prohibited from entering the warehouse; in the processing process, key process quality control points are established to monitor parameters such as heat treatment temperature and processing accuracy in real time to ensure that the processing quality meets the standards; in the testing stage, non-destructive testing technologies such as ultrasonic flaw detection and magnetic particle flaw detection are used to comprehensively detect key components, timely find defects such as cracks and inclusions, and prevent unqualified components from leaving the factory; in the assembly stage, precision assembly technology is adopted to control the fit clearance of components to ensure the smooth operation of the entire cardan shaft.
In addition, the maintenance and replacement of key components are also indispensable. During drilling operations, it is necessary to regularly inspect the key components of the cardan shaft, focusing on checking the wear of the cross shaft, the lubrication state of the needle bearing, and the meshing state of the spline pair, and handle abnormalities in a timely manner; for components that have reached the service life, they must be replaced in a timely manner to avoid cardan shaft failures caused by aging and failure of components, leading to unplanned shutdowns. At the same time, a traceability system for key components is established to record the production batch, test results, and usage of each batch of components, facilitating later maintenance and quality traceability, and further improving the operational reliability of the cardan shaft.