Desing and optimization of torsional rigid fan couplings

In applications requiring high flow rate in terms of capacity, safe powertrains are required to transmit high engine power to the fan mechanism. Torsional Rigid Fan Couplings must provide the necessary features in terms of environmental conditions, boundary conditions and service needs. In addition, the assembly and disassembly procedure of these fans during maintenance work is important in terms of service conditions. There are conical pulling exercises between the motor shaft and the coupling connection in the system without a wedge connection. The press power or heating operations required to apply wedge systems are not suitable for environmental conditions. For assembly and disassembly, precise tolerance lapping is applied by pulling the bolts on a conical plane. Torsional Rigid Fan Coupling elements are exposed to critical stresses during assembly and disassembly. It consists of two elements: clamping nut and flange. The clamping nut is made of AISI 4140 quality and the flange is made of S355 quality steel raw material. The choice of quality is that the tightening nut material is hard and the tightened flange material is less hard. The stresses resulting from precision lapping on the conical plane must be at the appropriate safety factor according to the yield strength for the S355 quality flange. In this thesis study, analysis and optimization studies were carried out on a coupling that was produced and in service with a reverse engineering approach. According to Taguchi parameter design method; Two different taper sizes, raw material quality, sharp corner radius and inner diameter dimensions were determined as parameters. Lubrication during assembly affects the coefficient of friction, which affects both good and bad conditions. Finite element analysis was performed for the flange element with eight different fitting tolerances and the optimum safety coefficient was determined according to the biggest, best approach. The optimum contraction result has been verified with precise running-in measurements calculated mechanically to ensure that the drivetrain transmits the nominal torque value.