TI worm gearing, namely toroidal involute worm gearing, consists of involutehelical gear and hourglass worm enveloped by the gear.

• TI 蜗杆传动,全称渐开面包络环面蜗杆传动,由渐开线斜齿圆柱齿轮及其包络的环面蜗杆组成。