Study On Molding Theory And Method Of Calculating Screw Holding Capability Of Micron Wood Fiber Molded Products For Cars

With the fast development of society,demand for luxurious car increases gradually. Wooden decorations in luxurious car,such as wooden panel,joy stick,doorknob,steering wheel and so on,are more and more popular.But lack of raw materials and complicated processing technology made wooden decorations very expensive.Ordinarily families and consumers can't afford to it.The micron wood fiber molded products proposed by this dissertation are workable replacements of wood parts in luxurious cars.It will solve the problems of material shortage,molding technology,and high cost.It will enhance the usage of wooden products in car industry and improve the consumption of luxurious car.Firstly,the dissertation studied the design theory of equipment processing micron wood fiber molded products for cars,analyzed the function,worked out an overall design plan, studied component system of the equipment,designed the structure and strength,and developed the experimental equipment of micron wood fiber molded products for cars.The designed structure of the experimental equipment is simple and rational.The speed of molding is high.It provided people a new experimental equipment of molding micron wood fiber products.With the equipment,plenty of experiments had been done and many samples of micron wood fiber molded products for cars were produced.We've got the molding technological method,route,key technological parameters and firsthand data for industrialized production.Meanwhile we studied the thread strength and control of veins tending of micron wood fiber molded products for ears.According to the experimental results,the correlative equation of screw holding capability and molding density is put forward,and the molding press curve is given.The study above forms the molding theory of micron wood fiber molded products for cars.Secondly,the method of calculating screw holding capability and the strength design of screw joints of micron wood fiber molded products according to molding process parameters and compound material mechanics were put forward.The mechanical model of screw thread of micron wood fiber molded products for cars was established.The load distributing curve and strength calculating equations of screw thread were deduced.The precise percentage of force in the threads was calculated.The equation of calculating screw holding capability of micron wood fiber molded produts was proposed.The computer program was edited so that the screw holding capability can be obtain rapidly.Experiments has validated that the strength of micron wood fiber molded products is higher than the products made of the same materials of natural woods.The design of micron wood fiber molded parts was proved to be successful.Further more,the relationship of forces,deformation of threads and the geometrical parameters of micron wood fiber molded products were analyzed in detail.The load distributing coefficient was deduced.The load distributing equation of the screw holding binding site of micron wood fiber molded products was established.Besides,the optimal design of strength of screw joints for micron wood fiber molded products with reliability was put forward.Thirdly,the questions and solutions of molding process of micron wood fiber molded products were analyzed.The calculating equations of screw holding capability of micron wood fiber molded products were proved by test.The error and reasons of the results of theory and test were analyzed too.The molding theory of micron wood fiber molded products for cars studied by this dissertation offered the molding equipment and technology.It applied the fundamental theory of micron wood fiber to car industry.The calculating method of screw holding capability of this dissertation is deep study of intersecting subjects of wood science and mechanics.Using computer,we can calculate the screw holding capability of various screw rapidly.The state that the screw holding capability of wood depends on experiments only will be changed.It will raise the working efficiency greatly.