Precise forming of teeth step on screw rotor by cross rolling

DOI:	10.11809/bqzbgcxb2023.08.038
Keywords:	screw rotor; cross rolling; teeth step; precise forming; finite element simulation
Abstract:	Screw compressor has been widely used in various industries such as air compressors and heat pumps due to its high work efficiency and easy realization of high rotate speed. Screw rotors are the key parts of screw compressors. Screw rotor has a complex spiral teeth step which causes a difficulty in manufacture. Traditionally, a round bar is milled to a blank for the screw rotor at first and then grinded to the final dimensions. The milling step is of low material utilization and time consuming. In this paper, a new precise forming technology of cross rolling for teeth step was proposed to produce the blank for screw rotor. The new method has higher productivity, higher material utilization and less machining afterward. In this paper, the mechanism of the cross rolling teeth step was revealed using numerical simulation and experiment. The stress and strain distributions in the forming process were analyzed and the rolling force was discussed. Experiment has been conducted to verify the possibility of the new method. Results showed that the rolled teeth profile well matched the design profile, and all the errors measured were between -0.71 mm and 1.2 mm. The rolled teeth were with high accuracy and precise forming of teeth step by cross rolling was feasible.
Published:	2023-08-28
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