Modeling Of Multiple-arcs Gear And Process Based On Form Grinding

Arc gear has larger carrying capacity, longer work life, easier to form the dynamic pressure oil film and lower sensitivity to the installation error and distortion than involute gear. But such superior performance gear is used with soft tooth surface technology status in industry currently, which greatly limits the its application scope. The reason is the process method (mainly grinding) of high precision hard tooth face of arc gear has not been solved. In recent years, with mature application of CNC form grinding technology in involute gear, the solution becomes more and more clear. A brief introduction of the work done by this paper is as follows:1The form grinding principle of Circular arc gearForm grinding has strong adaptability to tooth profile, so it breaks the thinking restriction of generating method grinding and gets rid of the dependence on generating method cutting tools, which provides the conditions for mature application of high precision hard tooth face of arc gear. Beginning from the form grinding principle this paper studies the features of form grinding and the choice of grinding wheel and trim preliminary.2The heat treatment technology of arc gearAmong the heat treatment technologies, tooth surface carburizing quenching is the most efficient way in improving tooth surface hardness and bearing capacity. Beginning from of involute carburizing gear, the general rule of Settings are sought, and the method is discussed to determine the effective case depth of carburizing arc gear.3The design of arc tooth profile and grinding wheel section shape adapting to form grindingThe geometric modeling method of high precision hard tooth face of arc gear are studied which conforms to the conjugate principle, then the accuracy of the model is verified by comparing the tooth profile to the one from simulation of machining. The final shape of tooth is determine by the shape of the grinding wheel’section in form grinding. The calculation method of the shape of grinding wheel’ section are analysed, which can provide theory basis for arc gear form grinding and create conditions for generating NC code in subsequent processing. Front point in basic tooth profile of double and four arc gear are modified to improve the strength of grinding wheel which can adapt to the form grinding technology. It make sure the tooth bending strength don’t reduce after modifying by using FEA software.4Some problems in the experiment of arc gearThe general issues on design of arc gear transmission are studied. It is pointed that the loading method of pulse fatigue test commonly used by academia now is not sensitive to the change of tooth shape in view of the situation of gear bending fatigue strength test which has a greater difference with the actual working situation. It results in the result reliability is difficult to guarantee, so it isn’t the same with bending fatigue strength test of multi-arc gear.