Induction Heat Treatment Analysis of the Rack in a Ball Screw for Vehicle Power Steering Systems

本文進行高週波感應技術用於車輛動力轉向系統之齒條部位熱處理之研究分析，針對非對稱硬化深度的要求，透過軟體模擬分析的方法，以了解線圈設計與感應加熱條件設定是否滿足設計之需求，而達到加速線圈修正的效率，減少製作錯誤線圈的可能性，進而縮短驗證的週期、降低失敗成本。 研究中，設計三種不同形式的線圈(圓形、切圓形、馬蹄形)搭配三種感應加熱的條件(10 KHz、500A/ 3 KHz、500A/ 10 KHz、1500A)及時間參數對於齒條進行電腦模擬，了解感應線圈對於齒條感應加熱的情形，進而從模擬結果得知頻率大小、電流大小、線圈形式、線圈位置等參數，皆會影響溫升狀況與溫度分布，當頻率較高時，齒條表面溫度可以達到要求，但其滲透深度不足；當頻率較低時，同時功率亦不足時，則所需要之加熱時間會過長，此導致熱傳導影響到心部區域，形成全硬化熱處理的現象；以低頻率、高功率，可以滿足設計的需求。以線圈形狀的設計而言，因馬蹄形形式與齒條的距離適中，使溫度滲透深度達到要求，搭配3 KHz與1500A的設定參數，可以作為未來線圈製作的參考依據。This paper deals with a computer analysis of the induction heat treatment of a rack for vehicle power steering system. Through the analysis, the appropriate coiler type and the setting of the induction heating conditions to meet the requirement. This can reduce the mistakes in design and processing of an asymmetric hardening depth can be known, thereby shortening the cycle on validation and reducing the cost due to failure. In the study, three different types of the coiler (round, cut-round, horseshoe) individually exerted with three induction heating conditions (10 KHz, 500A/ 3 KHz, 500A/ 10 KHz, 1500A) and various processing times are used to analyze the heat treatment of the rack. From the simulation results, the effects of electric frequency, electric current, coiler type and coiler position on the temperature distribution in the rack and obtained. When the electric frequency is high, the surface temperature on the rack fulfills the requirement. But the penetration depth is insufficient. When the electric frequency is low, a low electric power would need a long heating time. This leads the input heat to affect the core of the rack through heat conduction and causes the entire rack being hardened. At a low electric frequency and a high power, the result of the heat treatment meets the requirement. The horseshoe shape of the coiler provides a rather uniform distance between the rack and the coiler, which makes the penetration of the temperature reach the demand. Incorporating an electric frequency of 3 KHz and an electric current of 1500A, the combination can be treatment as a basis in the design of the coil for the heat treatment of the rack in the future.摘要 i ABSTRACT ii 目錄 iii 表目錄 v 圖目錄 vi 1、 緒論 1 1.1 前言 1 1.1.1 車輛轉向元件之應用與重要性 1 1.1.2 熱處理之方法種類 2 1.1.3 採用高週波熱處理之原因與產品之優點 2 1.2 文獻回顧 3 1.3 研究目的 4 1.3.1 研究之內容大綱 4 1.3.2 研究方向與內容之簡介 4 2、 感應加熱的原理 6 2.1 焦耳效應 8 2.1.1 磁滯損失 8 2.1.2 渦電流損失 9 2.2 集膚效應 10 2.3 鄰近效應 12 2.4 尖角效應 12 2.5 感應加熱之優點 12 3、 加工件的物理特性 14 3.1 電阻係數 14 3.2 相對導磁率 14 4、 ANSYS Multiphysics之電磁熱耦合分析 16 4.1 感應加熱理論架構 16 4.1.1 電磁場方程式 16 4.1.2 溫度場方程式 18 4.2 設計的目標 19 4.3 分析的規劃與模擬的流程 19 4.3.1 分析的規劃 19 4.3.2 模擬的流程 20 4.4 分析結果 31 4.4.1 線圈A的模擬分析 31 4.4.2 線圈B的模擬分析 35 4.4.3 線圈C模擬的分析 38 4.5 導R角對尖角效應的影響 43 5、 結論與未來研究 44 5.1 結論 44 5.2 未來研究 45 文獻參考 4