| 摘要: | 二階行星齒輪機構根據其連接關係及邊界條件的設定不同，會具有多樣性機構型態。而不同機構變體所具有之特性需透過計算才能得知。一般而言，個別機構的分析通常要有特定的計算模型，使一般設計人員在進行機構設計時，並不容易選擇合適機構變體與決定合適的齒輪設計參數。同時，在進行3D CAD圖檔繪製時，通常需在不同程式之間進行操作，如在繪圖軟體中將已經設計好之零件外型參數建立實體模型。然而二階行星齒輪機構所需要繪製出之零件變化型式眾多，因此容易產生參數誤植的問題。所以若能透過電腦程式的協助，讓設計者快速進行二階行星齒輪機構之分析及設計，並僅需在一整合介面輸入所有零件外型參數，再由電腦程式控制繪圖軟體自動完成3D模型之建立，便可以縮短二階行星齒輪之設計時間、提升開發效率。
本研究之目的主要在開發一個具有二階行星齒輪機構設計分析功能及3D CAD圖檔自動產生機制的電腦輔助設計系統。此系統可藉由程式介面引導設計者決定齒輪機構變體結構與設定對應機構參數，並藉此快速完成此變體之扭矩分配、機構速比範圍計算；再透過承載能力分析及受載齒面接觸分析確認齒輪基本參數符合需求；最後則可由系統產生連接元件之3D CAD圖檔。
為能進行二階行星齒輪機構之變體設計，本研究以外接元件屬性將變體機構分類並建立編碼原則。其中根據外接元件屬性可將變體機構分為並聯式機構、串聯式機構以及一進二出差速機構等三類。此三類機構之功率流動特性不同，而各階基本速比的設計又與其相關，因此藉由此分類可讓系統協助設計者了解變體機構之特性，並採用對應之基本速比設計方法。
為進行齒輪參數分析，則根據ISO6336建立標準化之齒輪承載能力計算程式模組及並將已發展之受載齒面接觸分析模型納入系統中，以便可以應用此系統快速進行齒輪基本參數分析確認其符合需求。
為能使選定變體能自動產生CAD實體模型，此系統以CAD樣板檔做為基礎，建立參數置換程式及開放式參數資料庫。系統根據所設定之變體，從參數資料庫讀入對並變數名稱，以及由計算結果與使用者自行決定來設定變數之數值，再利用參數置換程式讀入模型變數取，更新CAD樣板檔之參數。而設計者更可以依資料庫之參數記錄格式在開放式參數資料庫中新增自訂樣板檔對應參數，且可由同一套參數置換程式讀取並置換樣板檔中之參數。
;The two-stage planetary gear drives have various types of structure according to the different given coupling and boundary conditions. The characteristics of each variant can only be known through calculations, so it is necessary to establish specific formulaes. In general, it is not easy for designers to determine the appropriate mechanism variants and gearing design parameters while designing a two-stage planetary gear drive. Meanwhile the process of creating drawings for gear boxes often requires operations across different software, e.g., the parameters of designed parts need to be given into the drawing software to generate the CAD solid models. However, the planetary gear mechanism involves various types of parts, which can lead to parameter input errors. Therefore, with aid of computer programs, designers can quickly analyz and design a two-stage planetary gear drive, and if the design parameters for complex parts can be given through an integrated interface, allowing the program to control the drawing software and create the drawing automatically, it would greatly reduce the design time and enhance the development efficiency of two-stage planetary gear drives.
The aim of this study is to develop a computer-aided design (CAD) system that can be used to design and analyz a two-stage planetary gear drive and is capable of generating drawings automatically. The system can guide the designer to decide the structure of the variant and set the corresponding parameters of the mechanism through the program interface, and then quickly complete the calculation of torque distribution and the speed ratio of the mechanism. The designers can then confirm if the gearing parameters meet the requirements through the load capacity analysis and loaded tooth contact analysis; at last, designers can obtain the drawings of the connected components generated by the system.
In order to design the variant of two-stage planetary gear drive, this study classifies the variants by the properties of the external componet and establishes a coding principle. The properties of the external components can be used to classify the variants into three types of mechanisms: parallel mechanism, serial mechanism, and differnetial mechanism. The power flow characteristics of these three types of mechanisms are different, and the design of the basic speed ratios for each stage is related to tehm. So, this classification allows the system to provide the information to designers, and assit them to adopt the appropriate design method for the basic speed ratios.
In order to carry out the analysis of the gearing parameters, a standardized calculation module of the gear load capacity according to ISO 6336 is created and the developed model of the loaded tooth contact analysis is incorporated into the system, so that the basic parameters of the gearing can be analysed quickly with the help of this system to confirm that it meets the requirements.
Finally, for the automatic generation of CAD models, the system is designed on the basis of CAD template files. A parameter substitution program module and an open database of parameters are set up to substitute and record the parameters of the CAD sample files. According to the set variables, the system reads the corresponding variable names from the parameter database, and sets the values of the variables by calculation results and user′s own decisions, and then uses the parameter substitution program to read in the model variables and update the parameters of the CAD template file. The designer can also add the corresponding parameters of the customized template file into the open parameter database according to the parameter record format of the database, and the parameters of the template file can be read and replaced by the same parameter replacement program. |
