渐开线齿形链机构的啮合机理

基于齿轮齿条机构的啮合理论，研究了渐开线齿形链机构的啮合机理．分析了渐开线齿形链轮和链条的啮合状态，得出了变位系数的求解公式，发现变位系数与齿数和节距有关，并给出了变位系数的变化曲线．对渐开线齿形链轮的根切状态进行了研究，求解了不发生根切的最小齿数．研究了渐开线链轮的最小变位系数和唯一变位系数，发现链轮节距为9．525mm时，最小齿数应为17．基于包络原理和坐标变换公式，确定了渐开线齿廓和齿根圆之间过渡曲线的方程．求解变位系数和最小齿数的方法可适用于所有节距的齿形链机构．

Engagement theory of silent chain mechanism with involute tooth profile

The engagement theory of the gear rack mechanism can be used to study the silent chain mechanism.The modification coefficient of involute sprocket is achieved by the engagement analysis between the silent chain and involute sprocket.The result shows that the variation of the modification coefficient is influenced by the tooth number and the pitch.The variation curve of modification coefficient is given.The undercut of the involute sprocket is investigated to derive the minimum tooth.The research on the minimum and unique modification coefficient proves that the minimum tooth value is 17 as the sproc-ket pitch is equal to 9.525 mm.Based on the envelope principle and the coordinate transformation,the function of the transition curve between the involute tooth profile and root circle is conformed.The approach presented to achieve the modification coefficient and the minimum tooth number is applicable to the silent chain mechanism with all kinds of pitches.