| As an important part of automobile power transmission system,gear has the advantages of high transmission efficiency,reliable operation,long service life and stable transmission.When it comes to the traditional design methods,it is not only difficult to ensure the quality of gear design but also need a long design cycle.Therefore,it is of vital significance to efficiently design gear with high performance requirements.In this paper,the involute cylindrical gear is taken as the research object,and the parametric modeling method of gear structures,gears meshing transmission parameters design method and gears parametric modeling system are studied to provide evidence and guidance for the modern design methods of gear.The main contents are as follows:(1)Research on parametric modeling methods for gear structures.The parametric basic model of involute cylindrical gear structures is established and the mathematical models of gear structure parameters constraint are established by researching on the structural characteristics of different involute cylindrical gears.Using the fully programmed parameter modeling method,combined with the UG secondary development technology,the parametric program design of involute cylindrical gear shaft hole,hub,keyway,web plate and web plate hole are completed and the parametric modeling of involute cylindrical gear structures is realized.(2)Research on design methods of gears meshing and transmission parameters.Through in-depth research on the transmission principle of external cylindrical gears,and the geometric constraint mathematical models are established by analyzing the constraint conditions of gears correct meshing and transmission,which includes non-backlash meshing,avoiding undercut,not too thin tooth top,guarantee a certain coincidence degree and non-interference of tooth root transition curve.The mathematical models of tooth surface contact fatigue strength and tooth root bending fatigue strength are established by analyzing the constraint conditions of gear bearing capacity.Considering the geometric constraints and bearing capacity constraints of gears meshing and transmission parameters design,the mathematical models of gears meshing and transmission parameters design are established.(3)Research on the system for gears parametric modeling.In this paper,based on the mathematical models of gear structure parameters constraints and the mathematical models of gears meshing and transmission parameters design,taking UG 8.5 and Visual Studio 2010 software as the system development platform and combining VC++ object-oriented technology and UG secondary development technology,the gears meshing and transmission parameters design module,gears parametric modeling module and gears parameters data access module are established,and a special gears parametric modeling system is developed.Through setting system environment variables,customizing user menu,designing user dialog box,writing parameter design program and storing and reading data file,the rapid design and precise modeling of involute cylindrical gear structures are realized.The design system is tested with the data of external meshing gears design example,and the effectiveness of the system is verified.The gears parametric modeling system of this paper integrates gears meshing and transmission parameters design and gear structures parametric modeling,which can effectively shorten the research and development design cycle of cylindrical gear and improve the design and production efficiency.The system has certain engineering application value,and also has certain reference significance for the parametric design of other products. |
