漸開線插槽刮齒刀之刃部剛性研究

Abstract

刮齒法廣泛的運用在齒輪精加工製程上，刮齒後常發生齒型不良或是刮齒刀加工壽命不長等問題，這些問題往往歸咎於刮齒刀剛性不足所造成。現今常見的直線插槽刮齒刀的齒面與插槽槽底並非平行，因此沿著齒面的刃部端面至其根部長度皆不相同。本研究提出的漸開線插槽槽底構造，其槽底每一點皆與齒面平行，即刃部長度皆相同。期望透過幾何形狀的差異，以改善刃部剛性的穩定度。 本研究使用應變規在插槽刃部上進行應變測量，並與有限元素法分析結果比對驗證，將漸開線與直線的插槽刃部進行剛性的分析與比較。 實驗結果顯示，漸開線插槽刃部在受到相同的負載條件下，其平均應變為1.71E-4，直線插槽刃部的平均應變為2.15E-4，漸開線插槽刃部各測定點平均應變小於直線插槽刃部，與有限元素法分析結果一致。直線插槽刃部在節圓處測定點之應變量明顯高於其齒頂測定點，對於刮齒加工精度以及刮齒刀壽命有著較大的變數；而漸開線插槽刃部各點的應變值較為穩定，凸顯其漸開線插槽刃部剛性強度較佳，對於齒型加工精度以及刮齒刀壽命提升有較大的正面效果。

Shaving cutting is widely used in the gear manufacturing. However, due to the low stiffness of the shaving cutter, there are several quality issues, such as the poor gear profile or short life cycles. Nowadays, serration is made by straight type process on shaving cutter. The surfaces of the gear profile edge and the serration bottom face are not parallel. There are different lengths on each point of the serration. In this study, we modified the shaving cutter shape from the straight line to the involute line. The surfaces of the gear profile edge and the serration bottom face are parallel, so that each point of the serration has the same length. Through changing the shape of the shaving cutter, we expect it will have lower stree concentration and longer life cycle. In this study, we used the strain gauge to measure the strain around the serration. On the other hand, the CAE simulation was also used to compare the stiffness of the serration between the straight line and the involute line. According to the experiment and simulation results, the average strain value around the serration is 1.71E-4 in involute-line case and 2.15E-4 in straight-line case. The strain value around the serration in the involute-line case is smaller than that in the straight-line case. In the straight-line serration analysis case, the strain on the testing point close to the pitch circle is obviously higher than that on the other testing points. It will be tremendously affect the gear profile and cutter life. In the involute-line serration analysis case, the strain is more stable on each testing point. That means the involute-line structure would increase the stiffness of serration and improve the gear profile.