行程速比系数达到最大的曲柄滑块机构设计分析

Design and Study on Crank Slider Mechanism With Maximum Coefficient of Travel Speed Variation

曲柄滑块机构在函数生成、轨迹再现与刚体导引等领域得到了广泛应用,尤其在转动与移动的相互变换方面应用更多,在从转动到移动的变换中传动角最大化得到深入的研究,事实上,行程速比系数最大化也具有现实意义,基于机构的极限位置与最小传动角位置的几何关系,利用函数取得极值的必要条件,建立了许用传动角约束下的行程速比系数达到最大的曲柄滑块机构的六次代数设计方程,通过变量代换降为三次方程获得了解析解,设计实例表明了该方法的简明性与正确性。

Crank slider mechanism gets extensive use in function generation, path generation and rigid body guidance and so on, and used more especially in the mutual transformation aspect of revolution and translation. In transformation aspect from revolution to translation, maximum transmission angle is studied in depth. In fact, maximum coefficient of travel speed variation has practical significance too. Based on the geometric relations in limit positions and minimal transmission angle position of the mechanism, made use of necessary condition of function reaching extreme value, an algebraic design equation with sixth power is set up, it has maximum coefficient of travel speed variation and satisfies allowable transmission angle condition. An analytic solution is obtained by variable substitution reduced to third power algebraic equation. A design example shows its simplicity and exactness of the design method.