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About ProE ProE is a well-known 3D product modeling software from PTC Corporation of the United States. The modeling process takes the product features as the design unit and completes the design process through a combination of various features. The description of the various features is achieved by using different parameters, and the changes in the model can be achieved by changes in the parameters. All modules in ProE are related. Modifications to one feature can automatically change all relevant results through the internal parent-child relationship between features. At the same time, ProE uses a unified database to store all design materials during the design process, thus effectively ensuring the uniformity and correctness of the design.
The program module embedded in ProE records and builds the features of each part, records the establishment of its features, parameter settings, constraints and relationships, and through the program design in the Program module, can effectively realize human-computer interaction and complete Parametric modeling. At the same time, a series of sub-parts obtained by using the Program module can be automatically added to the part family table, and the design efficiency can be effectively improved by editing and managing the family table.
Analysis of three-dimensional modeling process of involute cylindrical gears By analyzing the characteristics of involute cylindrical gears [1], three-dimensional modeling of involute cylindrical gears needs to establish gear tooth profile surface features, gear wheel tooth profile and gear spoke structure. Features, the key of which is to generate the involute tooth profile surface features.
a. Establishing the gear involute profile curve feature The formation process of the involute [2] shows that the parameter equation of the involute in the Cartesian coordinate system is: x=rbsin(kk)-rb(kk)cos(kk ) y = rbcos (kk) rb (kk) sin (kk). (1) where the radius of the rb base circle; the pressure angle at the K point on the k involute; the spread angle at the K point on the k involute, k = tank-k.
In the ProE part solid design, choose to create a datum curve from the equation and input the parameter equation of the involute in the Cartesian coordinate system to generate an involute [3]. This involute creates a complete cogging in a mirror image. Or the teeth, you can create the corresponding tooth profile by stretching.
b. Establishing the structure characteristics of the gear spokes Firstly, the sketched section of the gear spoke structure is established, and then the cross section is rotated around the central axis to realize the structural characteristics of the gear spoke.
c. Establishing the gear tooth profile The above-mentioned involute profile curve features, through the array method, complete the establishment of all tooth profile surfaces on the entire circumference, and then apply the involute formation process to form the gear teeth. Body characteristics.
Three-dimensional parametric solid design of involute cylindrical gear In the three-dimensional modeling process of involute cylindrical gear, the main parameters used to determine the profile curve and spoke structure are: modulus m, number of teeth z, helix angle, pressure The angle, the tip height coefficient ha, the head clearance coefficient c, the tooth width B, the journal diameter D at the gear mounting, and the basic dimension bh of the key used for circumferentially fixing the gear. Among these parameters, the modulus m is obtained by the strength design. And should comply with national standards; the number of teeth z, the helix angle should meet the requirements of motion and strength; the pressure angle = 20, the height coefficient of the top of the tooth ha = 1, the coefficient of head clearance c = 0.25, are standard values; the tooth width B is designed for strength As a result, the journal diameter D at the gear mounting is determined by the shafting structure design; the basic dimension bh of the key used for circumferential gear fixing is available according to the journal diameter D of the gear mounting, and the strength requirement should be met. Under the premise that the above parameters are known, other dimensions used in the three-dimensional modeling process of the involute cylindrical gear can be calculated from these parameters [4].
In the ProE part entity design process, the program is designed using the Program module [5], the pressure angle, the tip height coefficient ha, and the head clearance coefficient c are given by parameters, as shown; application Notepad editing. Pls file (for the corresponding part model name), as shown, run the program, through the screen prompt, the user enters the modulus m, the number of teeth z, the tooth width B, the journal diameter D at the gear mounting, and the gear circumferential direction according to the design result. The basic size bh of the key used for fixing; other various feature sizes are calculated by relationship, as shown.
The three-dimensional parametric solid design of the involute cylindrical gear can be realized in two ways, such as the above process, by running the program, modifying the parameters, regenerating the model, and obtaining a new gear three-dimensional model; another way is by adding an illustration in the part A set of new design variables is generated in the family table to generate the corresponding derived parts, as shown.
The design example takes the involute spur gear as an example to complete the three-dimensional solid design of the gears with different parameters in the two groups. Applying ProE, the physical model of the gears 1, 2 is generated by changing the input parameters as shown.