Design of four shaft misaligned semi-automatic transmissions for agriculture tractors

When designing semi-automatic transmissions for tractors and automobiles the engineers of machine-building enterprises face the lack of techniques that allow uniquely identifying their design parameters. In particular, when determining the shaft layout in four shaft semi-automatic transmissions with shaft misalignment design with the need to respect the minimum width the mutual influence arises of geometry parameters and design of gears to each other and to the overall width the same time. In solving this problem it is necessary to resort to the use of graphic-analytical method with a large number of iterations that is time-consuming and does not provide a guarantee of repeatability of result. The article describes a technique that allows choosing rational parameters of the basic kinematic units to ensure minimal overall width, and uniquely identify its position in space. Sequence of design of semi-automatic transmission is reduced to the choice of gear ratios and the formation of a rational layout of shafts through which minimizing of its overall width is achieved. It was established that, on the basis of the kinematic parameters of the units it is possible to build a rhombus which completely determines the location of the shafts in semi-automatic transmission. For a complete description of the geometry of the rhombus and its position in space were obtained the corresponding analytical dependences allowing to determine the dimensions of semi-automatic transmission and the distance between the input and output shafts without the use of graphic-analytical method with a large number of iterations. The developed method of design of semi-automatic transmissions can be used to create similar assemblies for automobiles.