Research On The Theory And Method Of Spiral Bevel & Hypoid Gears CNC Machining Simulation Based On VR Technology

Spiral bevel and hypoid gear is widely used as a basiccomponent in mechanical products. Its complicated tooth surfacesmake its 3-D modeling difficult. Though there is much CAD softwarein the market, it is difficult to model accurately for spiral bevel andhypoid gear. If the 3-D model of the gear is created using CADsoftware with the help of the numerical calculation, there are a lot ofwork to do and the great disadvantage is that the model cannot bereused. When its parameters are changed, the model has to be recreated.Besides, trial cut is needed to adjust designing and manufacturingparameters in gearing in order to manufacture desirable tooth surfaces.The process of trial cut that sinks money and wastes time is hard tomeet the needs of the present market for the development of theproducts. Therefore, it is necessary to develop the special simulationsystem. According to the manufacturing characteristic of spiral beveland hypoid gear, the dissertation studies on CNC machining simulationof spiral bevel and hypoid gear by means of computer graphics,differential geometry, spatial kinematics, object oriented technologyand virtual realistic technology etc. And realistic simulation system hasbeen built. The theory and method of simulation are proved valid andreliable through practical manufacture.The principle of the kinematic transformation from traditionalmachine to CNC gear generator is introduced. The accurate formulasfor transformation are deduced based on the principle. In comparisonwith other methods, this principle has the advantages of clear inprinciple and the formulas are simpler.From the point of view of spatial kinematics,velocity-differentiating method is developed considering the movementof the former and latter transformation through resultant movementformed by transport movement and relative movement. The precisionof the method that solves coefficients of expansion of every axis ishigher than that of direct difference method. Besides, the method thatbreaks a new path for analyzing the complicated system is of universalmeaning in analytical methodology.That the program of the coefficients of expansion written moreconcisely and efficiently by Matlab is embedded the main program inVC solves the problem that VC is not good at dealing with the complexmathematical models and the problem that machining setting parametercannot be transmitted in time.By means of technology of 3-D realistic graphics, a simplifiedglobal illumination model is proposed to build the virtual environmentthat can simulate the NC machining environment more accurately.The process of metal cutting is analyzed from the aspect ofdimension position of workpiece and cutter, controlling the relativelocations of the bodies of cutter and workpiece drives the machine tool.The metal cutting process is simulated through subtraction Booleanoperation of two 3-D bodies in every period of time divided asuccessive cutting process into some finite period of time.According to the practical manufacture, the simplified principleof the entities of cutter and workpiece is brought forward. In the sametime, the open solid database of them is constructed. It makes thesystem more open and expansive that the object-oriented ideology hasinfiltrated into every module of the system. Hence it is accessible toupgrading the system.