在伞齿轮中(图2-22) ,大圆(节圆锥的底圆)上的周节称为伞齿轮的周节,而在大圆上所画的齿形与通过大圆上的节点而正交于节圆锥的圆锥(图中,以垂直于母线 OA 的 O_1A 为母线的圆锥,称为背锥)上所画的正齿轮的齿形相 In the bevel gear (Figure 2-22), the circumference of a large circle (the bottom circle of a pitch cone) is called the circumference of a bevel gear and the shape of a tooth drawn on a large circle is orthogonal to the point passing through a node on a large circle Section conical cone (in the figure, perpendicular to the bus OA O_1A for the bus cone, known as the back cone) on the painted spur gear tooth phase