The Design Of Unidirectional Continuous Flat Wedge CWR Machine

Continuous local plastic forming is an important aspect in the field of press working of metal, which has many merits, such as few equipment investment, fast fund transformation, high energy utilization ratio, stable production quality, realizing mechanization and automatizaion easily, saving material and so on, and which has been applied widely in rolling field.Cross wedge rolling belongs to continuous local plastic forming and is a new efficient process and technology for plastic forming of shaft products. As far as subject is concerned, cross wedge rolling is the intersection of metallurgic rolling and forging. Crossing wedge rolling and metallurgic rolling are both continuous rotary forming, i.e. they both belong to rolling category, but traditional metallurgic rolling produces products with constant section and usually provides semi-finished products, while cross wedge rolling produces products with variable section and it is the developement and deep processing of metallurgic rolling. Crossing wedge rolling and forging both belong to category of plastic forming, but being different from forging, crossing wedge rolling is continuous local forming. Cross wedge rolling has a high production ratio because of continuous forming and it also has other virtues because of local forming, such as low load, small equipment, long longevity of mould and so on.Cross wedge rolling machine can be mainly divided into cross wedge rolling machine and flat wedge cross wedge rolling machine. Cross wedge rolling machine has excellent rigidity, but its moulds are fan-shaped and have to be machined and heat-treated complexly, so the quality, precision and stability of forming is not good. The moulds of flat wedge cross wedge rolling machinecan be machined and heat-treated easily and the machine don't need guide plate when it works, so it can be applied to form workpieces with small radius and its precision and stability are good, but the overall rigidity of the machine is bad. In order to solve the problems in above machines, my tutor, Professor Song Yuquan, invited"plate-press rolling plastic finish shaping machine", which has been applied national patent. The machine in the patent utilized the high precision and simple mould of flat cross wedge rolling machine and excellent rigidigy of cross wedge rolling machine. As a plastic precise equipment applied to form multidiameter workpieces, plate-press rolling plastic finish shaping machine has synthetical merits of excellent rigidity, simple machining of moulds and high forming precision.Although plate-press rolling plastic finish shaping machine has many advantages, it still has some disadvantages. During the period of working of the machine, reciprocal engagement of gear ring and gear rack will inevitably cause error which will influence the precision of workpieces, and due to empty run existing in the course of working of the machine, Production ratio will be reduced, moreover, the machine hasn't solved the technological problem of forming large workpieces. Aiming at these problems, my tutor, professor Song Yuquan, thought repeatedly and pointed out unidirectional continuous flat wedge cross wedge rolling machine. Based on plate-press rolling plastic finish shaping machine, the machine applied unidirectional continuous transmission mechanism and realized unidirectional continuous engagement of gear ring and gear rack, which improved plate-press rolling plastic finish shaping machine further. Based on the patent of"plate-press rolling plastic finish shaping machine"and the idea of unidirectional continuous transmission, the paper designed unidirectional continuous flat wedge cross wedge rolling machine.According to the idea of unidirectional continuous transmission, the paper put forward the running scheme of unidirectional continuous flat wedge cross wedge rolling machine, and then analyzed the problems existing in this scheme and solved the difficulties among it. Finally, the paper made sure the running scheme and structure scheme of the overall machine.Integral structure of the machine mainly includes main machine part and unidirectional continuous transmission mechanism. Main machine part is the foundation of the machine, which is composed of frame, adjustable setup of central distance between upper and lower rollers, roller shafting. The design of unidirectional continuous transmission mechanism is emphasis as well as difficulty, including the design of upper and lower of toothed chain, level guide rail, tension mechanism and turning mechanism. Based on the demand of the patent of plate-press rolling plastic finish shaping machine, the diameter of gear ring is equal to that of gear rack. During the course of designing, the diameter of roller is determined firstly, then the diameter of graduated circle of gear ring is determined according to the diameter of roller, then modulus and tooth number of gear ring are detemined, finally the length of tooth chain is determined according to the dimension of the biggest workpiece and number of workpiece rolled by the machine after the tooth chain runs a circle. The turning mechanism is the mechanism that made racks turn. The tension mechanism made tooth chain tense properly and run stably in order to prolong its longevity.Using three-dimensional modeling software UG, the paper designed the integral machine and prepared numerical models for analysis with finite element method and dynamic analog simulation. Frame and roller are important parts, and the strength and rigidity of frame directly determine longevity and precision of the integral machine. Roller endures draught pressure and roll torque during the course of forming and it is in a complicated stress situation, so the strength and rigidity of frame and roller need to be checked. Because the shape of frame is complicated, there are more hypothesis when calculating its strength and rigidity by mean of material mechanics and elastic mechanics, so the process of calculation is troubled and the precision of calculation is low. In consideration of above factors, the paper applied finite element method to analyze the strength and rigidity of frame and roller. The numerical models of frame and roller are transmitted to the software of ANSYS, then their rigidity and deformation are analyzed and contour of equivalent stress and contour ofsum displacement are gained. And finally, the results are analyzed. Using UG motion modular, the paper simulated the overall operation of equipment and get the running locus of rack chain and the vertical direction displacement change of tension wheel. By analyzing the result, the feasibility of overall operation scheme was verified further.By analyzing innovation and features of unidirectional continuous flat wedge cross wedge rolling machine, its merits can be seen obviously, which include high production ratio, high forming precision, simple drive system, removing oxide skin easily and so on, moreover, the machine can be applied to form large multidiameter workpieces, for example, transimission shafts of heavy-duty truck and axle shafts of train. The success of research of the machine will enrich existing equipments of cross wedge rolling to meet practical demands of new processes, and as a result, it will promote the development of manufacturing of our country.