Research On The Three-roll Cross Rolling Forming Laws Of The Duplex Gear Blank

Duplex gear is a kind of basic part, which is widely applied in engineering machinery, and its blank is a disk part with two steps in cross section. Traditionally, the manufacturing method for duplex gear blank is forging and cutting, and there exists some problems such as larger energy consumption, more materials wastage and lower efficiency.With the arrival of low carbon economic society, development requirements of various industries tend to be low-power, low-pollution and low-emissions. Therefore, a new specific rolling technique called three-roll cross rolling is first presented for the forming of duplex gear blank in this paper.The three-roll cross rolling technology belongs to continuous local plastic forming process and obviously has the advantages of effort-saving, energy-saving, material-saving, high efficiency, and good quality. Meanwhile, the three-roll cross rolling is also an unsteady and high nonlinear process with multi-factors coupling interactive effects. So, in order to put the technology into practice to play its advantages successfully, the basic study on it has made in terms of theory, numerical simulation and experiment. The content is mainly concentrated on the following points:1. Theoretic analysis. On the basis of reasonable mechanical model of biting groove, motion model in the rolling process and calculating displacement model of main roll, the biting condition of workpiece in three-roll cross rolling process, the expressions of sizes and rotation speed of workpiece in the rolling process and expression of feed amount of main roll required to complete the forming of workpiece are all obtained. Meanwhile, some influence parameters and influence laws are also analyzed.2. Numerical simulation. A 3D coupled thermo-mechanical FE model of three-roll cross rolling of a duplex gear blank is developed under the ABAQUS software environment, and its validity is verified. Base on the model, some basic forming laws of three-roll cross rolling for duplex gear blank is revealed. In addition, the effects of technological parameters on the uniformity of the plastic strain and temperature distributions, rolling force and rolling force moment are also investigated.3. Experiment. Simple modification scheme for exist machine in laboratory, which is a New-style vertical numerical control (nc) hot-rolled ring machine, is made to meet the demand of conducting the three-roll cross rolling experiment. Beside, the rolls, blank and technological parameters are designed.