加工弧齿锥齿轮的精确双重螺旋法（Ⅳ）──弧齿锥齿轮副小轮理论齿面计算点及曲率的确定

The Exact Duplex Helical Generation of the Spirial Bevel Gears(Ⅳ)──The determination of the calculating point and its curvature of the pinion surface of the spirial bevel gears

根据啮合原理，确定出与已加工的弧齿锥齿轮副大轮作共轭接触的小轮理论齿面及与大轮齿面计算点相对应的小轮理论齿面计算点的位置。在加工小轮时，并不要求切出这个理论齿面。其原因有两点：一是小轮理论齿面无法精确加工出来；二是小轮理论齿面与大轮啮合情况不理想，因为它对制造、装配中的误差及变形过于敏感。为此，采用理论齿面的二阶近似齿面来代替，即计算出理论齿面在计算，点的各个方向法曲率，得到局部的接触，对它作一定的修正。最后确定出大轮和小轮的测量尺寸。

This paper confirmed the theoretical tooth surface of the pinion making a conjugation contact with the generated gear of the spirial bevel gears and its calculating point position contrary tothat of the gear. This theoretical tooth surface did’t need generating while generating the pinion. Therewere two causes: first,the theoretical tooth surface of the pinion wasn’t generated exactly,second,theengagement between the theoretical tooth surface of the pinion and the gear was not very good,for it wasverv sensitive to the errors and deformation in its manufacture and assemble. So the tooth surface of thepinion was replaced by the second-order approximate surface of the theoretical tooth surface. The curva-ture of all directions of the calculating point were calculated,and made it correct in orde to require partcontact, This paper also confirmed the measuring sizes of the gear and pinion.