Development process and application of new product

  • Detail

With the rapid development of the automotive industry and the widespread application of computer technology in the automotive industry, the design means of passenger cars in China has also changed from the original manual drawing to computer-aided CAD, and has gradually been replaced by three-dimensional design. The following is a brief description of the two common basic processes in the development of new passenger cars and the specific application of Unigraphics (hereinafter referred to as UG) in the development of new products

1 two basic processes

two common basic processes in the development of new passenger car products are shown in Figure 1 and Figure 2

the author takes the ck6580 product of his company as an example to discuss the specific scheme

2 application of two processes

2.1 scheme 1

1) through a large number of market research, and under the influence of the government's policy of vigorously promoting the process of connecting villages and villages, it is found that the passenger transport market urgently needs a light bus that is flexible and convenient for medium and short distance transportation between urban and rural areas, and has good economy, so the ck6580 bus of the company came into being. Its main technical parameters are as follows:

overall dimensions (mm)

length x width x height 5760x 1990x2560

front suspension/rear suspension/wheelbase 850/1710/3200

front wheelbase/rear wheelbase 1600/1480

Interior height 1850

mass (kg)

curb weight of the whole vehicle 3000

front axle load capacity, rear axle load capacity 1200/1800

maximum load capacity.T.4490

front axle bearing capacity, Rear axle load 1910/2580

basic performance parameters

maximum speed (km/h) 90

maximum climbing gradient (%) 30

approach angle decay angle (.) 24/16

fuel consumption (U100 km) ≤ 12

approved passenger capacity (person) 10-17

2) chassis selection or self-development according to the determined technical parameters. In order to make this model more competitive in the market and in combination with the main operating road conditions, the company has developed a ck6560d3 Lusheng chassis to adapt to it. The chassis adopts 4dw93-84e3 diesel engine, with a rated power of 67 kW, a fuel tank volume of 70 L, and a maximum driving range of 600 km. The main assemblies and parts adopt the existing accessories in the market with a large amount of stock, which can not only make the products relatively reliable, but also have great cost advantages

3) draw product effect drawing. Fully reflect the distinctive, personalized and innovative modeling style, and according to the main technical parameters, professional designers draw several 1:5 or 1:10 renderings, including front view, rear view, left view, right view, left front 45. Etc., as shown in Figure 3

① description of overall modeling style. The style of the whole vehicle is round, full, avant-garde and influential

② description of the elements considered in the front wall modeling:

a. the round lamp combination is integrated into the exaggerated modeling to make the front face more avant-garde

b. the bumper and medium styling elements are derived from off-road vehicles, which are not only filled with (3) good chemical stability, full of wildness, but also give people a sense of security

c. the highly inclined front wall curve can effectively reduce the wind resistance coefficient and improve the use economy of the whole vehicle

③ description of side wall modeling style:

a. the side window modeling meets the needs of front wall modeling. 10. One Lenovo brand computer, which gives people a sense of speed; The side windows are arranged symmetrically left and right, which is conducive to deformation combination

b. an outward protruding curved surface is added at the lower part of the side wall, which not only makes the whole vehicle look long, but also gives a sense of stability

c. the car like outer skin of the wheel housing makes the shape of the whole vehicle more fashionable

④ description of the elements considered in the rear wall modeling:

a. the combination of rear wall round lights echoes the front and rear, which can not only effectively reduce costs, but also facilitate maintenance

b. the design of double rear windshield mainly considers the deformation combination of passenger and freight vehicles

4) scanning effect diagram. Use a professional scanner to scan the renderings. Due to the limited space, I will not elaborate here

5) reverse 3D model:

① open the industrial design module of UG, and import the scanned image into the UG working interface in the format of TIFF file, and enlarge the corresponding proportion to 1:1

② adjust the position of each picture to the correct position, and set the absolute coordinate origin as the vehicle coordinate origin

③ draw the contour line and smooth it. For the contour lines that are symmetrical on the left and right, the method of smoothing one half, copying one mirror image, merging one smoothing is adopted

④ scan or stretch each contour line into a face, and use the face to cut the entity to preliminarily complete the prototype of the model

⑤ then make the rest of the model carefully according to the effect drawing, simulate the wind tunnel test in the computer, analyze the results, and then optimize the modeling

⑥ complete the design of the basic six sided skeleton of the bus, and optimize the design by using finite element analysis. Finally, divide the front and rear windshield glass, front and rear headlights and other components, and finally make the shape achieve the overall effect drawn in the effect drawing, as shown in Figure 4

6) export 2D engineering drawings. Each department selects materials, prepares materials, and makes samples according to the engineering drawing to prepare for trial production

7) for trial production. In the trial production process, the production and inspection shall be carried out in strict accordance with the drawings to ensure the accuracy in the trial production process. If any unreasonable place is found, the drawings shall be checked and revised in time, and the trial production records shall be made to prepare for the later product improvement

8) the retention life of the ball screw is much higher than that of the trapezoidal screw. After trial production, modification and trial production for one or several times, when there is no problem, the whole vehicle product identification test can be carried out, and finally the batch production can be carried out

2.2 scheme II

1), 2), 3) steps refer to 1), 2), 3) steps in scheme I

4) making 1:2, 1:5 or 1:10 sludge models (see Figure 5) the production of reduced scale sludge models has become a crucial step in today's design frontier. Its purpose is to reproduce the idea of modeling design with real objects, verify the three-dimensional effect of the effect drawing, carry out optimization and scheme demonstration, and can also be used to compare the effect of wind tunnel tests

Figure 5 sludge model

5) qualified units can send the completed sludge model to the wind tunnel laboratory for testing, analyze what is unreasonable, and then optimize the modeling and wind resistance coefficient

6) the coordinate data of the modeling surface can be obtained efficiently and accurately by measuring the three-dimensional coordinates and processing the point cloud of the passenger car sludge model verified by analysis

7) use Imageware, the three-dimensional reverse software of UGS company, to carry out reverse modeling, and finally complete the establishment of three-dimensional computer model

8) next, it can be completed step by step according to 6), 7) and 8) of scheme 1

3 conclusion

scheme 2 requires automobile manufacturing enterprises to have wind tunnel laboratories, three-dimensional scanners or coordinate measuring instruments in order to calculate the results more accurately. At present, only a few large enterprises with strong strength have them. Therefore, scheme 1 is more suitable for most enterprises, especially small and medium-sized enterprises. (end)

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