Research And Development Of Static Balance Measuring System On Huge Marine Propeller

Marine propeller is the core component of the ship, which is the large rotating machinery, its static balance characteristics directly affect the stability, the safety and the reliability of the ship. Due to the unreasonable design, the installation errors and the other reasons in the manufacturing process, the unbalance magnitude affects the overall performance of the propeller ultimately. The rolling method by balance shaft is used to test propeller static balance, but the traditional method has some shortcomings, such as the heavy central axis, the flexible core shaft and the inconvenient disassembly, etc.The method can not meet the current enterprise's the requirements of high measuring precision and measuring convenience. Considering the requirement of Zhenjiang Ship Propeller Factory and the theory of static balance detection for rotating machinery, the main research contents are as follows:(1) By analyzing the present situation of the marine propeller static balance testing and the existing problems of the traditional method, an approach based on the principle and detection theory of static balance for propeller was designed, which can meet the operation requirements properly.The project realized the automation of static balance testing process and increased the security of the system.(2) The model of the suspending system,the centering system, the control system and the software system that were the main parts of the static balancing system had been set up. The function of the main parts have been analyzed.The suspending system was designed to achieve low friction and improve test accuracy; the control system was designed for alignment between the hole of the propeller and the worktable; the software system was designed to deal with data and reduce the errors caused by artificial experience.(3) By using the theory of fluid dynamics and the theory of oil film, the friction and static characteristics of the suspending system was done. The suitable structure parameters of the spherical pair were chosen through the performance characteristic of hydrostatic bearing and leakage rate. At the same time, the oil film stiffness, oil thickness and work characteristics were calculated. Finally, considering the performance, production process and the cost of production, the designing strategy was given out.(4) According to the need of detection system, the system which included software and hardware was established. In order to achieve the accurate data, the sensor, isolating amplifier and analog quantity acquisition module must be selected properly. The software system was designed in modular and interface was friendly. I n order to achieve the detection of data management, the VB language and Access database knowledge was studied.The soft system was convenient for users to check historical data and output the test report.