감속기를 고려한 500톤급 고속정의 축계 정렬 해석에 관한 연구

Abstract

Generally, the shaft alignment calculation is required as mandatory according to classification societies rule requirement in case the propulsion shaft diameter is greater than 300mm or 400mm depending on classification societies. The shaft alignment calculation is therefore not required for patrol ships whose propulsion shaft is lower than 300mm in diameter. According to the manufacturer guideline, the reduction gear bearings of the patrol ships, however, should be reviewed to avoid any quality cases due to misalignment during the design stage if the reduction gear is installed to the patrol ship. In this study, the necessity of shaft alignment analysis of the propulsion shafting system in the 500ton class patrol ship was evaluated. First, all bearing loads are evaluated depending on the application of shaft alignment analysis and bearing s tiffness such a s infinite o r e stimate v alues. S econd, in o rder to e valuate the e ffect o f the propeller shaft bearing types on the reduction gear bearings, it was studied how the loads of the reduction gear bearings change with the bearing types of rubber and thordon bearings as strut, aft and forward stern tube bearings. As a result, in case of the shaft system alignment analysis was not carried out, it was verified that the analyzed reduction gear bearing loads are not within permissible load range given by the manufacturer regardless of the bearing types. Conclusively, it was confirmed that the 500ton class patrol ship hav ing the reduction gear i s able to secure the reliability, s tability of the gear bearings only when the shaft alignment analysis is carried accurately considering the stiffness of the strut bearing and the stern tube bearings.