TY - JOUR N2 - This study describes the methodology for modelling a worm and worm wheel of a double enveloping worm gear with the use of a CAD system. An algorithm for generating a globoid helix is described. In addition, the methodology for modelling an hourglass worm thread with a straight axial tooth profile is presented. The shape of the hourglass worm tooth end with and without a trace modification is proposed. Moreover, a method for achieving a geometric modification of the tooth trace was developed. Next, the method for modelling the worm wheel teeth is described. A solid model of using a machining worm as a hob is applied. Owing to the limitations of a CAD system, which prevents the use of a direct machining simulation, an indirect modelling method is introduced. In the present study, different CAD techniques, both solid and surface, are applied. Knowledge of the correct modelling of the hourglass worm and worm wheel facilitates their generation and conducting various analyses, including a tooth contact analysis. CAD models are utilised to analyse the geometrical contact pattern in a CAD environment, to carry out FEM analysis, to manufacture real parts or to prototype models using the technique of rapid prototyping. They can be also used as master models for measurement, e.g. in optical technics. L1 - http://www.czasopisma.pan.pl/Content/119420/PDF/27_01950_Bpast.No.69(2)_26.04.21_K2_G_OK.pdf L2 - http://www.czasopisma.pan.pl/Content/119420 PY - 2021 IS - 2 EP - e136736 DO - 10.24425/bpasts.2021.136736 KW - globoid surface KW - CAD modelling KW - double enveloping worm gear KW - globoid helix KW - hybrid modelling KW - tooth trace modification A1 - Połowniak, Piotr A1 - Sobolak, Mariusz A1 - Marciniec, Adam VL - 69 DA - 09.03.2021 T1 - Double enveloping worm gear modelling using CAD environment SP - e136736 UR - http://www.czasopisma.pan.pl/dlibra/publication/edition/119420 T2 - Bulletin of the Polish Academy of Sciences Technical Sciences ER -