槽轮机构一种新曲线槽的设计

Design of a new kind of curved groove on geneva mechanism

针对常用直槽槽轮机构在销轴进、出槽轮槽口时产生冲击的问题,采用圆向量函数的矢量回转和坐标变换的方法,在保证槽轮和销轮转动角度关系不变,并将压力角控制在可用范围的前提下,设计了一种新的槽轮曲线槽,并给出了其数控铣床加工的刀具轴线轨迹。以槽数4、销轮和槽轮中心距33 mm、销轴半径2 mm、铣刀半径2mm为例,设计曲线槽槽轮机构;用槽轮角加速度与销轮角速度平方的比值表示冲击大小,结果为:销轴进入槽轮槽口时该比值为0.00,但销轴出槽口时相对直槽冲击有所增大,该比值约为-1.96,最大压力角增为12.19°;而对于同样尺寸的直槽槽轮机构,销轴进出槽轮槽口时比值分别为1.00和-1.00,最大压力角约11.69°。所设计的槽轮机构可消除销轴进入槽轮槽口时的冲击,并可用于工程实际中。

To abate the impact of a pin wheel and groove in a conventional geneva mechanism during entering and exiting of the pin wheel, a new kind of curve groove was designed by the methods of vector gyration and coordinate transform of circle vector functions under the conditions of an unvaried rotary relation of the pin wheel and the groove and an useable range of maximal pressure angle, And the axial track of the grooving cutter on the NC-machine tool was given. The impacting magnitude, expressed by the ratio of the angular acceleration of the groove and the square of the angular velocity of the pin wheel, in a such designed mechanism indicates that the ratio is 0 when the pin wheel enters the groove; while is about - 1.96 when exits and the maximal pressure angle is about 12.19°. For the same magnitude in conventional geneva mechanism the ratios will be 1.00 and - 1.00 respectively and the maximal pressure angle will be about 11.69°,