| Popis: |
Gears are machine parts used to transfer torque from one shaft to another. Gears are widespread and their application is indispensable in all industries that produce different drive mechanisms. Each pair of gears makes one transmission, so the transmission can be singlestage or multi-stage. Like other mechanical transmissions, they are usually used to reduce the speed from the drive shaft to the driven shaft. The shape of the gears depends on the relative position of the drive shaft and driven shaft. During rotation, gear teeth are periodically in mesh, and the magnitude of the forces acting on them is constantly changing. Except of the basis on certain norms, the gear calculation is also based on experimentally determined coefficients, but lately, experimental determination is increasingly being replaced by computer numerical analyses, which are cheaper and faster methods. In order to obtain accurate and reliable results of numerical analyzes, it is necessary to have the most accurate three-dimensional gear geometry. The tooth profile is determined by mathematical curves whose final shape depends on several input parameters. The change of each parameter implies a series of computational operations that recalculate the point coordinates of the curves in order to describe the tooth geometry. By parameterization, this process is automated and significantly accelerated, and the obtained gear geometry satisfies all the requirements related to precision and accuracy. CATIA software does not contain a library of gears, so they need to be modeled from scratch each time, which is time consuming and tedious. Often 3D gear models are simplified or approximated, which is why their precision and accuracy are no longer sufficient to generate reliable results from the performed numerical analyzes. This paper presents a procedure of parametric design of spur gears using the CAD software application CATIA V5 |
