傾斜式液壓升降平臺車設計
傾斜式液壓升降平臺車設計,傾斜式液壓升降平臺車設計,傾斜,歪斜,液壓,升降,平臺,設計
黑龍江工程學院本科生畢業(yè)設計
附 錄
附錄A
Modified Car Lifting Platform Based on CATIA Modeling and Application of Digital Prototyping
Describes the use of CATIA V5 mechanical parts i and zero-dimensional modeling, virtual assembly of the basic process components and steps, and worm assembly, for example in detail. The effect of improving the mechanical design to improve design efficiency and shorten the design cycle time, has some practical significance
1 Overview
CATIA software from IBM and Dassault company to launch high-end CAD / CAM software, has become the international aviation industry preferred design software. With its strong surface design features in the machinery, aircraft, automobile, shipbuilding and other widely used design, CATIA surface modeling capabilities is reflected in the features and advantages it provides a very rich modeling tools to support the user modeling needs. As its unique high-order Bezier curve and surface features, the number can reach 15, can well meet specific industry demanding requirements of surface smoothness. Application CATlA constructed solid model can be directly applied to other analysis software ANSYS finite element analysis CATIA software with three-dimensional CAD software and other standard data interface for easy data conversion model.
CATIA V5 is based on the Windows platform, and to fully parametric feature modeling technology as the core feature-based modeling software, which is consistent with the Windows-style menu bar, standard shortcuts, contextual menus, multi-document interface, you can make the difference Windows applications to share data, OLE integration, so work quickly and efficiently, can significantly reduce training time. CATIA parts assembly is basic, but also the most advantages and features function modules, including the creation of an assembly, add the specified components or parts to the assembly, the assembly relationship between components to create, move and layout of the assembly members, generated an explosion of products diagram, assembly interference and gap analysis and other major features?.
2 three-dimensional modeling based on CATIA and assembly
2.1 Design sketches
Sketch design is the starting point of three-dimensional design, and its essence is a two-dimensional line, surface design, software design with a traditional two-dimensional functions. Parametric design of the basic approach is to start from scratch design, size and geometric constraints imposed by creating a sketch feature, then apply the size-driven technology to automatically generate parts of the three-dimensional solid model, in the use of technology to generate two-dimensional contour sketches do not have to outline the exact size of the input , the parameters in the future to get the design process. Thus, during the product design, you can always adjust the design size, without a clear early in the design of the design size, enhance the ease of CAD software, to better achieve a user-friendly design, but also for the design of series improvement of products and original products and parts "borrowed" are convenient.
2.2 to generate three-dimensional part blank
CATIA has a strong three-dimensional solid modeling functionality, the user plane in the sketch, after drawing two-dimensional graphics, into the part design (Part Design) modules, you can rotate, stretch, lofting, stiffened, and other methods to generate the draft three-dimensional parts to be rough. Constraints can also use parameterized functions to be modified according to need. Designers can change for the body part blank to achieve the design process by "drawing" to "design" changes, and CATIA V5 provides three-dimensional model of the specific features make the design more similar to the production process, better to achieve a combination of design and processing.
2.3 complete the three-dimensional modeling
CATIA V5 provides feature-based design, will feature as a design element, the characteristics of the product as a combination, through the object from the class to be achieved step by step description of the specific shape of the design. After generating the rough three-dimensional parts can be used to drilling, slotting, shells, chamfer, plus convex sets, such as T with internal and external threads on the "rough" to "processing", the final completion of mechanical parts solid modeling.
2.4 complete the virtual assembly
Virtual assembly is using virtual assembly technology, three-dimensional computer model will be assembled together, it can avoid the application of physical prototypes, but also for parts for clearance and interference testing, reduce the sample error rate. In the product design process can use various techniques such as analysis, evaluation, simulation, and give full consideration to the assembly areas and related products during the various possible factors. Product performance and functionality to meet the conditions to improve the product assembly structure, the design of the product not only assembly, and minimize assembly cost and total product costs, shorten design cycles.
CATIA-based virtual assembly model has parallel, bottom-up and top-down approach to product development, this article focuses on bottom-up design. Construct the first module in the parts of parts of the three-dimensional model, then components in the assembly module to create constraints between the position, orientation relationships, about the relationship between parts to quantify the actual with the virtual assembly process between the various components entities location constraint relationship. In this way, parts of the geometry is being used in the assembly process, and not simply be copied to the assembly, to truly realize the part of the "virtual" assembly.
CATIA assembly workbench provides a flexible and intuitive tool to determine the relationship between parts. Workbench allows users to assemble the component parts and various sub-assemblies combined together to form the final assembly in the assembly environment, according to the defined constraints, parts can be modified, analysis, and relocation HJ. CATIA features with a single database, regardless of how editors edit parts and components where the whole assembly of parts to maintain the consistency of association, if you modify the components, assemblies that reference it automatically updated, real-time components reflect the latest change. Virtual assembly steps: the assembly provided in CArllA bench, leaders need to assemble the parts and components (CATIA provides the main method of inserting parts into parts, into the products, parts and insert new components into existing, etc.) . Then, the constraints on the components and the establishment of appropriate assembly relationship, according to the requirements of the different parts of the assembly, use a different constraint relations, and finally get a complete assembly model.
And Pro / E compared to the assembly process using CATIA has automatically created two parts to be assembled their design basis points of overlap between components to facilitate the designer a clear design basis between the assembly and parts between the base difference.
3 Design Example
The worm drive, for example, the use of CATIA modeling and assembly process and methods described.
3.1 to create three-dimensional model worm
Analysis of the structure of the worm part, clearly the main features of the structure to determine the modeling steps. By rotating the worm body, composed of the alveolar and keyway parts, the basic characteristics of a rotating body.
3.1.1 Create three-dimensional model of the worm part
(1) in draft mode to draw shapes according to the rough shape of the worm rough sketches, the establishment of size constraints, such as size changes, chamfer, etc. (of course, also in the formation of rough chamfer after the entity).
(2) In the design mode, the use of rotating parts (Shaft) tool to generate worm blank.
(3) According to the worm's parameters, to calculate the alveolar pitch worm and the worm screw according to the mode of curves and surfaces generated a worm wrapped around the spiral, as the slot scanning wire.
(4) Since the end of cylindrical worm Archimedes Archimedes spiral, oblique axial plane to a straight line ∞], so the worm shaft can choose almost plane, in draft mode, draw a trapezoid (must be a closed curve), its distance from the axis of the bottom margin is just the worm tooth root radius, both sides of the edge and face angle of 20. (Note: The pitch at both sides of the edge distance should be the pitch circle space width).
(5) in the part design mode using the narrow slot (Slot) tool to generate an alveolar; use the whole array of tools to worm out of the alveolar process.
(6) in draft mode to draw shapes keyway, the use of stretch cutting (Pocket) tool to generate key slot, to complete the three-dimensional construction of the worm
Mode.
3.1.2 create three-dimensional model worm parts
Analysis of worm parts of the structure, clearly a major component characteristics to determine the modeling steps. As the worm gear and ring gear teeth by the core 2 parts, so the ring gear and the tooth should be separated from the core model, and then assembled.
Parts using CATIA modeling platform provided by the ring gear and the worm were generated tooth core.
3.2 parts of the assembly
3.2.1 Import Parts
Assembly in CATIA provides the product structure workbench tool bar, use of existing parts into the function of the prior conductivity has been designed worm and worm parts.
3.2.2 the establishment of binding
As part of the import process CAITA has established a worm in the worm and the axial profile width of 1 / 2 of the face overlap constraint relations, has pledged its profile in the worm drive of the main (center section) on the alignment, in The only other two to determine the direction of the constraint relationship. Center distance worm gear in accordance with requirements (center distance worm and worm gear during physical modeling, based on the geometric parameters of worm and worm calculated), the establishment of the worm and worm wheel axis offset between the axis of restraint to ensure that the difference between the distance to meet the design requirements.
Along the axis of the worm to establish worm constraint relation, which is to ensure "in the middle of the worm and worm gear worm side of the axis of symmetry perpendicular to the plane" and "worm width 1 / 2 symmetry on the alveolar surface profile" coincidence (Note: during the worm and worm wheel solid modeling calculations must be accurate, otherwise it will not be accurate worm and worm wheel working position) to ensure that the worm and worm gear installed in the corresponding position. Generated as shown in Figure 1 worm drive assembly model.
4 Conclusion
CATIA 3D design software design tools provide a complete and convenient user interface, the interface and options designed with a consistent style with Microsoft products, greatly reducing the user for the software to learn and adapt to the cycle, to a large extent improved the operation of complex 3D modeling software defects. Meanwhile, CATIA feature-based 3D modeling functions it has the following advantages:
(1) inherited the use of solid modeling software for product design, the user can directly see on the screen the true three-dimensional model of the product characteristics, to model their ideas closer to the body composition, more intuitive design.
(2) parametric design changes to facilitate the graphic size, quickly plotted, relative to the two-dimensional graphics methods, designed to greatly reduce the workload, especially in the subsequent parametric design for the technical staff provides an easy design, easy to modify the platform, facilitating product serial design.
(3) The feature-based modeling idea, the use of Boolean operators seeking intersecting lines, intersecting lines, the engineering drawing speed faster, more accurate line.
(4) assembly method using a virtual machine, you can directly check the product design space mechanical system components and assembly of interference and to further visualize the design and analysis, concurrent engineering has a certain significance.
附錄B
基于CATIA的汽車改裝式升降臺數(shù)字樣機建模及應用研究
介紹了利用CATIA V5進行機械零件i維造型以及零、部件虛擬裝配的基本過程與步驟，并以蝸輪蝸桿裝配為例進行詳細說明。對于改善機械設計的效果、提升設計效率、縮短設計加工周期，具有一定的現(xiàn)實意義
1 概述
??? CATIA軟件是IBM公司和Dassault公司合作推出的高端CAD／CAM軟件，現(xiàn)已成為國際航空工業(yè)首選的設計軟件。它以其強大的曲面設計功能在機械、飛機、汽車、造船等設計領域得到廣泛應用，CATIA的曲面造型功能的特點和優(yōu)勢體現(xiàn)在它提供了極豐富的造型工具來支持用戶的造型需求。如其特有的高次Bezier曲線曲面功能，次數(shù)能達到15，能很好地滿足特殊行業(yè)對曲面光滑性的苛刻要求。應用CATlA構(gòu)造的實體模型可直接應用于ANSYS等分析軟件中進行有限元分析。CATIA軟件具有與其他三維CAD軟件標準的數(shù)據(jù)接口，方便模型數(shù)據(jù)的轉(zhuǎn)換。
??? CATIA V5是基于Windows平臺的全參數(shù)化和以特征建模技術為核心的特征造型軟件，它與Windows保持一致風格的菜單條、標準的快捷鍵、上下關聯(lián)的菜單、多文檔界面、可以使不同的Windows應用程序共享數(shù)據(jù)的OLE集成，使工作快速高效，可顯著減少培訓時間。零件裝配是CATIA基本的、也是最具優(yōu)勢和特色的功能模塊，包括創(chuàng)建裝配體、添加指定的部件或零件到裝配體、創(chuàng)建部件之間的裝配關系、移動和布置裝配成員、生成產(chǎn)品的爆炸圖、裝配干涉和間隙分析等主要功能?。
??? 2 基于CATIA的三維造型與裝配
??? 2．1 草圖設計
??? 草圖設計是三維設計的起點，其實質(zhì)是二維線、面設計，具有傳統(tǒng)二維軟件設計的功能。參數(shù)化設計的基本方法是從草圖設計開始，通過施加尺寸和幾何約束生成草圖特征，再應用尺寸驅(qū)動技術自動生成零件的三維實體模型，在利用草圖技術生成二維輪廓時不必輸入輪廓的準確尺寸，可以在以后的參數(shù)設計過程中得到。這樣，在進行產(chǎn)品設計時，可以隨時根據(jù)需要調(diào)整設計尺寸，而不必在設計之初就明確各設計尺寸，增強了CAD軟件的易操作性，更好地實現(xiàn)了人性化設計，而且對于設計系列產(chǎn)品及原產(chǎn)品的改進和零部件的"借用"都方便。
??? 2．2 生成三維零件毛坯
??? CATIA具有很強的三維實體建模的功能，當用戶在草圖平面繪制二維圖形后，進入零件設計(Part Design)模塊，可以通過旋轉(zhuǎn)、拉伸、放樣、加肋、拔模等方法生成所需的三維零件毛坯。同時還可利用參數(shù)化約束功能，根據(jù)需要隨時進行修改。設計者可以直接針對零件毛坯進行形體改變，實現(xiàn)了設計過程由"繪圖"向"設計"的轉(zhuǎn)變，而且CATIA V5提供的各項具體功能使三維模型的設計更類似于生產(chǎn)加工過程，較好地實現(xiàn)設計與加工的結(jié)合。
?? 2．3 完成三維造型
??? CATIA V5提供基于特征的設計，即將特征作為設計的單元，將產(chǎn)品視為特征的有機結(jié)合，通過由類到對象的逐步描述來實現(xiàn)具體的形狀設計。在生成三維零件毛坯后，可利用打孔、開槽、抽殼、倒角、加凸臺、內(nèi)外螺紋等T具對"毛坯"進行"加工"，最終完成機械零件實體造型。
??? 2．4 完成虛擬裝配
??? 虛擬裝配是利用虛擬裝配技術，在計算機上將三維模型裝配到一起，這樣可避免物理原型的應用，也可對零部件進行間隙和干涉檢驗，減少樣品差錯率。能在產(chǎn)品設計過程中利用各種技術手段如分析、評價、仿真等，并充分考慮產(chǎn)品的裝配環(huán)節(jié)及其相關過程中各種可能因素的影響。在滿足產(chǎn)品性能與功能的條件下改進產(chǎn)品的裝配結(jié)構(gòu)，使設計出的產(chǎn)品不但可以裝配，并盡可能降低裝配成本和產(chǎn)品總成本，大大縮短設計周期。
??? 基于CATIA的虛擬裝配模式有并行、自下而上和自上而下的產(chǎn)品開發(fā)方法，本文重點介紹自下而上的設計方法。先在零件模塊中構(gòu)造各零件的三維模型，然后在裝配模塊中建立零部件之間的位置約束、定位關系，即將零件間的實際配合關系量化為虛擬裝配過程中的各零部件實體之間的位置約束關系。這樣，零部件的幾何體是在裝配過程中被利用，而并不是簡單地被復制到裝配中，真正地實現(xiàn)了零件的"虛擬"裝配。
??? CATIA的裝配工作臺提供靈活、直觀的工具，用來確定各零件間的關系。裝配工作臺允許用戶將各個組成零件和各種子裝配件組合到一起形成最終的裝配體，在裝配環(huán)境中，根據(jù)定義的約束，零件可以被修改、分析以及重定位HJ。CATIA具有單一數(shù)據(jù)庫的特性，不管如何編輯零部件和在何處編輯零部件，整個裝配部件保持關聯(lián)的一致性，如果修改整個零部件，則引用它的裝配件自動更新，實時反映零部件的最新變化。虛擬裝配的步驟：在CArllA所提供的裝配工作臺上，導人需裝配的零、部件(CATIA提供的插入部件的方法主要有插入部件、插入產(chǎn)品、插入新部件和插入已存在的部件等)。然后，對零部件進行適當?shù)募s束并建立裝配關系，根據(jù)不同零件的裝配要求，選用不同的約束關系，最后得到完整裝配模型。
??? 與Pro／E相比，使用CATIA進行裝配的過程中已經(jīng)自動建立了2個待裝配零件各自的設計基準點的重合關系，便于設計者明確零部件的設計基準與零部件間的裝配基準之間的差別。
??? 3 設計舉例
??? 以蝸桿傳動為例，對利用CATIA的建模及其裝配的過程和方法進行說明。
???? 3．1 創(chuàng)建蝸桿三維模型
??? 分析蝸桿零件的結(jié)構(gòu)，明確主要特征結(jié)構(gòu)，確定建模步驟。蝸桿是由旋轉(zhuǎn)體、齒槽及鍵槽組成的零件，其基本特征是一個旋轉(zhuǎn)體。
??? 3．1．1 創(chuàng)建蝸桿零件三維模型
??? (1)在草圖模式根據(jù)蝸桿毛坯形狀繪制毛坯形狀草圖，建立尺寸約束，諸如尺寸修改、進行倒角等(當然倒角亦可在形成毛坯實體后再進行)。
??? (2)在零件設計模式下利用旋轉(zhuǎn)(Shaft)工具生成蝸桿毛坯。
??? (3)根據(jù)蝸桿的參數(shù)，計算出蝸桿齒槽的螺距，并根據(jù)蝸桿的旋向在曲線曲面模式下生成1條纏繞在蝸桿上的螺旋線，作為開槽掃描導線。
??? (4)由于阿基米德圓柱蝸桿的端面為阿基米德螺旋線，軸面為斜直線∞]，所以可選擇蝸桿軸乎面，在草圖模式下，繪制一個梯形(必須是1條閉合曲線)，其底邊距軸線的距離正好是蝸桿的齒根圓半徑，兩側(cè)邊與端面的夾角為20。(注意：節(jié)圓處兩側(cè)邊的距離應為分度圓齒槽寬)。
??? (5)在零件設計模式下利用狹槽(Slot)工具生成1個齒槽；利用陣列工具加工出整個蝸桿齒槽。
??? (6)在草圖模式下繪制鍵槽形狀，利用拉伸切割(Pocket)工具生成鍵槽，完成蝸桿的三維建
??? 模。
??? 3．1．2 創(chuàng)建蝸輪零件三維模型
??? 分析蝸輪零件的結(jié)構(gòu)，明確主要組成特征，確定建模步驟。由于蝸輪是由齒圈和齒芯2部分組成，所以應將齒圈和齒芯分開建模，再進行裝配。
??? 利用CATIA所提供的零件建模平臺分別生成蝸桿的齒圈和齒芯。
???????? 3．2 零件的裝配
??? 3．2．1導入零部件
??? 在CATIA所提供的裝配工作臺上的產(chǎn)品結(jié)構(gòu)工具欄中，利用插入已有部件功能導人事先已經(jīng)設計好的蝸輪和蝸桿零件。????
3．2．2 建立約束
??? 由于在導入部件的過程中CAITA已建立了蝸桿軸向剖面和位于蝸輪寬度1／2處的端面重合的約束關系，已經(jīng)保證了其在蝸桿傳動的主剖面(中心剖面)上的對齊，在此只須確定另2個方向的約束關系。按照蝸桿傳動的中心距要求(中心距在進行蝸桿和蝸輪的實體建模時，根據(jù)蝸輪與蝸桿的幾何參數(shù)計算獲得)，建立蝸桿軸線與蝸輪軸線間的偏移約束，確保二者之間的距離滿足設計要求。
?????建立蝸輪沿蝸桿軸線的約束關系，即保證"位于蝸桿中部與蝸桿軸線垂直的蝸桿齒側(cè)對稱平面"與"蝸輪寬度1／2處剖面上齒槽對稱平面"重合(注意：在進行蝸桿和蝸輪的實體建模時必須計算準確，否則將得不到蝸桿和蝸輪的準確工作位置)，保證蝸桿和蝸輪安裝在對應的位置上。生成如圖1所示的蝸桿傳動裝配模型。
??? 4 結(jié)束語
??? CATIA三維設計軟件提供了完整的設計工具及方便的操作界面，其界面及選項的設計采用了與微軟產(chǎn)品一貫的風格，大大縮短使用者對于該軟件的學習和適應的周期，在很大程度上改善了3D造型軟件操作復雜的弊端。同時，CATIA基于特征的三維實體建模功能使其具有如下優(yōu)點：
??? (1)繼承了利用實體造型軟件進行產(chǎn)品設計時，使用者在屏幕上能夠直接看到產(chǎn)品的真實三維模型的特點，使其建模思路更加接近于形體本身的構(gòu)成，造型設計更加直觀。
??? (2)參數(shù)化設計便于圖形尺寸更改、迅速出圖，相對于二維繪圖方式，設計人員工作量大大減少，特別是其后參數(shù)化的設計為技術人員提供了1個便于設計、便于修改的平臺，有利于產(chǎn)品的系列化設計。
??? (3)采用基于特征的建模思想，利用布爾運算求截交線、相貫線，使工程圖繪制速度更快捷，線型精確度更高。
??? (4)采用虛擬機械裝配方法，可以在產(chǎn)品的設計階段直接檢查機械系統(tǒng)各零部件空間裝配情況和干涉情況，進一步實現(xiàn)可視化的設計和分析，對實現(xiàn)并行工程具有一定的意義。
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