Strength And Fatigue Research Of Key Parts In A High Power Marine Gearbox

As a key component in marine power system, gearbox has higher comprehensive technical indicator because of the high precision, the complicated structure, the severe working environment and the heavy load operation condition, etc. Therefore, the research of strength and fatigue life of key components in a high power marine gearbox have extremely significant in improving the product quality、guaranteeing the safety and reducing the accidents rate.In this dissertation the helical gears and articulation hole bolt are studied and the aims is to master the information of impact stress, stress distribution and the gear tooth’s deformation accurately in the gear meshing process. Then, based on the achievements, the effect of tooth profile modification of the involute helical gears and fatigue life of articulation hole bolt are studied. The results show an important practical application in design、optimization、 employment and maintenance of gearbox’s transmission system. The work can be summarized as follows:Firstly, the tooth profile 3D model of the involute helical gears are built accurately, applying by applying parameterization technique and Pro/E software. A new method is presented for achieving virtual assembly at random position without interference by the gear meshing surface and then a precise FEM is constructed.Secondly, the regularity of impact stress, stress distribution and tooth deformation in double or three helical gear teeth meshing process are calculated by the finite element software ANSYS Workbench respectively, and comprehensive influence of friction and tooth root fillet are considered.Thirdly, according to the deformation of gear tooth obtained in the static contact analysis, two schemes of helical gear tooth profile modification are proposed. Then using the finite element software ANSYS/LS-DYNA the dynamic contact is studied for a pair of involute helical gears with different profile modification. The results show that profile modification can reduce the stress concentration and improve the contact pressure distribution effectively.Finally, based on the fact that articulation hole bolt of the gear in higher power gearbox is always snipped abnormally, the fatigue life of articulation hole bolts are studied by the FEM software ANSYS Workbench, and the influence of profile modification on fatigue life is done too.