连续分度冷滚打机床滚打头结构改进

采用连续分度方式冷滚打花键时滚打轮和工件间存在一个干涉运动，实际生产中将机床滚打头部分整体倾斜一个安装角以减小干涉量。在安装角作用下，滚打轮成形轮廓发生变化，带来新的成形误差。分析了干涉现象产生的原理，设计了改进的滚打头结构，利用斜铜套将滚打轮自转轴反向倾斜一个安装角，使滚打轮成形轮廓不变。建立了计算滚打轮在键槽截面上成形曲线的数学模型，利用键槽宽度误差对冷滚打成形误差进行了表征。当冷滚打机床采用现有滚打头结构时，设置安装角虽然提高了成形精度，仍存在较大的成形误差；采用改进的滚打头结构时，安装角在一定范围内取值，干涉量和滚打头倾斜带来的成形误差均减小为0 mm. 改造机床滚打头部分进行冷滚打实验，精确测量了试样键槽轮廓，结果表明：不设置安装角时，键槽宽度误差的实测值与理论计算相符；设置安装角时，键槽宽度误差的实测值及其相对变化量都很小。实验验证了改进的滚打头结构的合理性。

Structure Improvement of Roll-beating Head for Continuous Indexing Cold Roll-beating Machine

Movement interference between roller and workpiece appears during continuous indexing cold roll-beating of involute spline. The rotary shaft of roller can be tilted at a setting-angle to reduce the interference. The forming profile of roller changes to cause new forming errors under the action of setting-angle. The principle of interference is analyzed, and the improved structure of roll-beating head is designed. The roller is inclined in the opposite direction at a setting-angle by an inclined copper bearing, which ensures the forming profile of roller. A mathematic model is established for calculating the forming profile curves of roller on the keyway section , and the forming errors are characterized by keyway width errors. The forming errors are still large when the existing structure of roll-beating head is used, although the forming accuracy is improved under the action of setting-angle. The interference and the forming errors brought by the inclination of roll-beating head are eliminated in a suitable range of setting-angles when the improved structure of roll-beating head is used. The roll-beating head is improved for cold roll-beating experiment. The keyway profiles of samples are precisely measured. The result indicates that the measured values of keyway width errors are consistent with the theoretical values without the action of setting-angle, and the measured values of keyway width errors and their relative variations are both very small under the action of setting-angle.