平面二次包络环面蜗杆减速机其蜗杆齿面是以一个平面为母面，通过相对圆周运动，包络出环面蜗杆的齿面，再以蜗杆的齿面为母线，通过相对运动包络出蜗轮的齿面，称为平面二次包络环面蜗杆副。平面二次包括以下三种PWU，PWO，PWS型三种形式，此产品适用于冶金，矿山，钢铁，起重，运输，石油，化工，建筑等行业机械设备的减速传动。
The worm tooth surface of the plane double enveloping toroidal worm reducer is formed by a straight line oblique to the worm as a generatrix and a circular arc spiral motion relative to the worm. It is a non-developable curved surface and cannot be used for worm grinding with normal processing technology. In order to achieve a certain hardness of the worm tooth surface, the worm is generally hardened and tempered first, and then processed with a special turning tool. The worm must also be modified to achieve a contact surface of more than 95% of the worm wheel and the worm.
Therefore, the output torque of the plane double-envelope reducer is much larger than that of ordinary arc gear, arc cylindrical worm reducer, cylindrical worm reducer and other reducer products.
