Rotor clearance is necessary for the safe operation of twin-screw compressors, and it has a major impact on the performance of twin-screw compressors. The purpose of this study was to obtain a rotor tooth profile with reasonable meshing clearance on the rotor end surface, so that the clearance on the rotor contact line would be uniform and the rotor could be smoothly meshed. Under ideal conditions, the rotor of a screw compressor should have no clearance or interference. However, owing to assembly errors, thermal compression, stress deformation, and other factors, a rotor without backlash modification will inevitably produce interference during operation. A new design method based on the Alpha shape solution was proposed to achieve an efficient and high-precision design of the clearance of the twin-screw rotor profile. This method avoids the complex analytical calculations in the traditional envelope principle. The best approximation of the points on the rotor conjugate motion sweeping surface in the points is illuminated using a specific color. The sweeping surface of the screw rotor single-tooth profile is roughly scanned to capture the base point set of the sweeping surface boundary points. The chord length and tilt angle of each interval are calculated using the value of the base point set to adjust the position, phase, and magnification of each interval sweeping surface. Finally, the data point set is converted to the same coordinate system to generate the conjugated rotor profile. An example was used to verify the feasibility and adaptability of this method. Based on the equidistant profile method, the clearance between male and female rotors of a screw compressor was obtained under actual operation conditions. Therefore, this study provides a basis for the meshing clearance design in the machining of twin-screw compressor rotors.
YANG Jian, ∗ (杨 剑), XU Mingzhao (徐明照), LU Zheng (陆 征)
. Design of Twin-Screw Compressor Rotor Tooth Profile with Meshing Clearance Based on Graphic Method and Alpha Shape Algorithm[J]. Journal of Shanghai Jiaotong University(Science), 2023
, 28(2)
: 243
-254
.
DOI: 10.1007/s12204-021-2396-z
[1] TANG Y, FLEMING J S. Computer aided geometrical analysis of the geometrical characteristics of a helical screw compressor [C]//1st International Compressor Technique Conference. Xi’an: International Institute of Refrigeration, 1993: 400-408.
[2] STOSIC N, SMITH L K, KOVACEVIC A. Calculation of rotor interference in screw compressor [C]//3rd International Compressor Technique Conference. Wuxi: International Institute of Refrigeration, 2001: 134-142.
[3] STOSIC N, SMITH L K, KOVACEVIC A. Rotor interference as a criterion for screw compressor design [J]. Journal of Engineering Design, 2003, 14(2): 209-220.
[4] XIONG W, FENG Q K. Calculation to inter-lobe clearance distribution of twin-screw compressor [J]. Journal of Xi’an Jiaotong University, 2004, 38(7): 682-685 (in Chinese).
[5] XIONG W, FENG Q K. Study of rotor interference in screw compressors based on three dimensions [J]. Chinese Journal of Mechanical Engineering, 2005, 41(6): 55-59 (in Chinese).
[6] LITVIN F L, FUENTES A. Gear geometry and applied theory [M]. Cambridge: Cambridge University Press, 2004.
[7] STO?I? N. On gearing of helical screw compressor rotors [J]. Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, 1998, 212(7): 587-594.
[8] L?CR?MIOARA P C, VIOREL P. Profiling disk tool for generating female rotor screw compressor component by meaning of graphical method [J]. Procedia Manufacturing, 2018, 22: 85-92.
[9] HE K, LI G L, DU Y B, et al. A digital method for calculation the forming cutter profile in machining helical surface [J]. International Journal of Mechanical Sciences, 2019, 155: 370-380.
[10] WU Y R, CHI J W. A numerical method for the evaluation of the meshing clearance for twin screw rotors with discrete tooth profile points [J]. Mechanism and Machine Theory, 2013, 70: 62-73.
[11] LAI J Y, HUANG Y C, LIN F Y, et al. Meshing simulation and clearance evaluation of real screw rotors [J]. Journal of the Chinese Institute of Engineers, 2012, 35(7): 887-900.
