- 學位論文
滾珠螺桿之熱效應分析與實驗印證
The Thermal Effects Analysis and Experimental Verification for Ball Screw
摘要
滾珠螺桿為精密線性傳動元件，由於滾珠與軌道之摩擦效應使螺桿在高轉速下會產生比低轉速時更劇烈之熱效應，而摩擦熱會使滾珠螺桿元件產生不同程度之熱膨脹，是影響定位精度之主要原因。本文以有限元素分析軟體，探討摩擦熱效應對於螺帽之影響，並藉由滾珠螺桿運動學之理論分析，計算出接觸角範圍、平均熱通量，將滾珠接觸角之變化頻率考慮為一個常態分佈曲線等。邊界條件則考量螺帽往復運動過程中所受到的對流效應來設定，以建立螺帽熱分析模型。分別分析螺桿螺帽之熱變形對於內部接觸幾何之變化，探討不同溫昇時之熱效應所產生的變形量。 實驗部分，以斜背式滾珠螺桿試驗機對滾珠螺桿進行實機測試，在螺帽適當位置設置熱電偶，及時量測螺桿與螺帽之溫度變化曲線，並與模擬結果相互驗證，確認模擬可信度。因此本文的熱模型可以應用在滾珠螺桿熱效應抑制使用建議及螺帽溫控設計上。
並列摘要
Ball screw is a kind of accuracy linear transmission component. But with high rotational speed will cause more thermal displacement effects than low rotational speed. It produces different degrees of thermal expansion and a principal affecting reason of the positioning errors. A Finite element method (FEM) is used to construct a thermal analyzing model of nuts under frictional heating effects. The heat source model used ball screw kinematics to calculate a range of contact angle and average heat flux, the ball contact angle is considered as a normal distribution conditions. Boundary conditions of the analysis model have considered reciprocation by air convection effect. Thermal deformation analysis of the screw and nut were considered with internal contact geometry and temperature rise thermal effects, respectively. In the experiments, In-situ testing is held in hatchback machine of a ball screw system. This work puts the thermal couples inside the nut in order to instantaneously measure the variation of temperature, then it is can be used in the comparing with the simulation and experiment. Finally, results from experiment and simulation were confirmed for verification. Using the proposed model incorporating thermal is placement is easy applied in analysis of temperature rise control system.