Application of the hottest catiav5 on Yutong Bus C

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The application of CATIA V5 in Yutong Bus Chassis

Zhengzhou Yutong Bus Co., Ltd. introduced CATIA to complete the design of an electronic sample car of a certain model in order to improve the design quality of products and the success rate of one-time design, reduce the design cost and reduce the design changes caused by design errors. In the chassis design, the main model design, structural design, DMU and other key technologies were discussed and adopted for the first time, and the frame of self-made chassis was completed The design of suspension, engine mount and other models also fully reflects the application value of CATIA V5 as a computer-aided design software

I. overview

the application technology of computer-aided design of domestic two-dimensional drawing board has indeed increased a lot of profits for enterprises in existing labor-intensive enterprises, and also accelerated the speed of product development. However, in terms of verification of product design quality and rationality of product structure, it still needs to rely on many times of physical trial production of new products, and the one-time success rate of design is not ideal

after a year and a half of research, the company decided to cooperate with Xi'an Jiangda technology/ibm PLM department, take CATIA as the platform for technical means improvement, and take the project development of a certain model as the starting point to jointly complete the design task of the electronic prototype, in order to lay a good foundation for its next implementation in the company, and cultivate a number of CATIA technology application backbones at the same time

in the chassis design process of the electronic prototype, according to the structural characteristics of the chassis, the design process was clarified, and the main model design method, structural design technology, DMU navigation and spatial analysis technology were decided to complete the chassis design of the electronic prototype

II. Key application technologies

1 The establishment of the main model of the chassis

when using CATIA to design the main model of the chassis, it is necessary to comprehensively consider the structural form of the frame, the layout of the engine and chassis assemblies, the structural form of the suspension, etc., to determine the main dimensions and parameters of the vehicle, as well as whether the assemblies interfere with each other, whether it is easy to install and maintain, etc

simply speaking, the main model is the skeleton or torso of a model composed of some simple points, lines and surfaces. In the modeling process of each assembly of the chassis, only some points, lines and surfaces in the main model are cited as reference elements for the modeling of each assembly. Of course, the "reference" here can be published or the relationship of element level copy link can be used to further expand its utilization range of biological sample transmission

in the process of establishing the chassis main model, the following three points need to be considered:

(1) simplification of the main model

the less points, lines, planes and other elements that the main model can control, the better, which is conducive to the realization of variant design of products. For example, in the chassis design, the parameterization of the whole chassis can be achieved by changing the parameters of front suspension, rear suspension and wheelbase, so as to meet the requirements of developing a new chassis

(2) management of main model

when establishing the main model, many points, lines and surfaces will be generated. If the tree is not organized and managed, the position of these elements in the tree must be very messy. If so, the references of these elements in the later assembly or component design are also easy to be confused. The maintenance of main model elements can superimpose and compare multiple experimental curves in a group; It will also be a headache

therefore, in the process of establishing the main model, some key points, lines and surfaces should be stored under different open bodies in an orderly manner, and the open body should be named according to its specific meaning

for example, in the process of establishing the main model of the frame design, several open bodies such as the main reference plane, the front assembly reference frame, the rear assembly reference frame and the middle assembly reference frame were used successively

(3) elements and references between chassis assemblies

after the chassis main model is established, when each major assembly references the elements on the main model, it must reference the elements that are crucial to itself. On the basis of the referenced elements, the referenced elements establish its own sub model of each assembly

for example, by referencing the absolute origin, three coordinate planes, front axle center plane and rear axle center plane on the main model of the chassis, and taking these elements as references, the sub model of the frame can be established. After the establishment of the frame model, then establish the sub model structures of the assemblies on the frame, such as the front and rear frame, the assembly beam, the main truss assembly, the side beam assembly and so on, so as to realize the overall preassembly of the frame structure. Figure 1 shows the main model architecture of a vehicle chassis

Figure 1 chassis main model architecture

2 The establishment of structural profile library

the frame is the foundation of the chassis, so the design structure of the frame must be considered when considering the configuration parameters of the chassis. Due to the advantages of CATIA structural design module, we adopted the method of combining this module with GSD and PDG when designing the frame. In the structural design (Sr1) module of CATIA, all profile libraries cannot meet the requirements of the company's original profile standards, so the enterprise must establish its own profile library before design

the general steps to establish a structural profile library are:

(1) use Sketcher to establish a profile section diagram. When building the section diagram, we should consider the parametric establishment and driving of the model, and then create a design table, as shown in Figure 2:

Figure 2 section parts

(2) change the design table and add some component features and parameters under part family

(3) open the catalog editor (Library), and create the enterprise's own library file, as shown in Figure 3:

Figure 3 section library

(4) change the structure file, find the project file in the installation path startupequipmentandsystems projectdata folder, modify the sections catalog and structure sections path paths, and specify them as the relevant paths of the catalog library file and sectionpart file just built above

(5) change the environment setting path, and use CATIA environmenter to modify it according to the red box in Figure 4

Figure 4 CATIA environment

(6) after entering tools project management under Sr1 module, specify the project file just modified, and you can directly use the customized profile library

3. Establishment of frame, suspension and engine mount models

as mentioned above, after establishing the sub model of the frame, considering the specific structure of the frame of this model, we use Sr1 module to design the frame. The frame adopts a three section structure: the middle section is designed as a truss structure, and the front and rear sections adopt a trough section beam structure. According to the characteristics of the frame itself, the frame assembly is divided into front and rear section assemblies and middle section assemblies during modeling, and the sub model of each assembly is formed by quoting elements from the frame model and expanding. When modeling, the structure of the frame can be established first, and then the assemblies can be expanded until a complete frame model is formed, as shown in Figure 5

Figure 5 frame model

when establishing the sub model structure of the front and rear suspension, reference elements such as the front axle center plane of the main model, the outer sides of the left and right girders of the frame, and the upper plane of the girders need to be referenced to generate the sub model of the suspension on this basis. Figure 6 and Figure 7 are the model diagrams of the front and rear suspension of the chassis respectively

Figure 6 front suspension model

Figure 7 rear suspension model

engine mounting system because of its own uniqueness, it is complex to establish its sub model. But it also refers to the outer side of the left and right rear longitudinal beams and the center plane of the rear axle in the shelf model as its key elements, and on this basis, it constructs its own sub model through complex GSD surfaces. In this way, when establishing the parts and assemblies of the engine mounting system, the constraints can be easily realized through its sub model architecture. Figure 8 shows the final pendulum impact tester. What should be paid attention to in use? The model diagram of engine mounting with longitudinal water tank

figure 8 engine mount model

in this way, the pre assembly of each assembly can be completed through the assembly design module, and the model of the whole chassis can be established, as shown in Figure 9

Figure 9 chassis assembly model

after the three-dimensional model of the chassis is established, in order to analyze whether there is interference between the chassis assemblies and the internal parts of each assembly, and whether the installation and maintenance of parts are convenient, we can use the DMU space analysis of CATIA V5 for DMU verification. It can check and calculate the interference such as collision, clearance and contact, and get more complex and detailed analysis results, so as to modify the chassis main model in turn

III. conclusion

we have completed the development of a vehicle chassis on CATIA V5 platform. Through the catalog editor (Library) of CATIA V5, the enterprise's standard structural profile library is established, which greatly shortens the design time of grid and format parts and improves the design efficiency. At the same time, some valuable explorations have been made on the concept of the main model, and the main model of the chassis of this model has been established. On the basis of the main model, the frame design, suspension design and engine mount design of the chassis have been completed by using the Sr1, GSD and PDG modules of CATIA V5, and the three-dimensional model of the chassis has been established. All these provide an excellent reference for the future vehicle design. (end)

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