Rotor Dynamic Design Optimization of 8 Lobe Camshaft for High Pressure Fluid Pump Applications

Rotor dynamic plays exceptionally imperative part in the structural stability. The high speed alongside damping in the structure causes the system should wobble and brings about wear of the cam bearings. Resonance is those generally undesirable characteristic of dynamic problems. Resonance happens in the problem because of matching from claiming operational frequency and natural frequency of a system. In this work, 2 station 8 lobe cam shaft will make analyzed for rotor dynamic states to avoid wear out of the bearing because of higher vibrations. Initially analytical calculations are carried out to find the load acting on the cam system. Plunger diameter and pressure inside the fuel pump are the major parameters for calculation of loads. Using simple mechanics of material concepts, the validation of theoretical results with finite element results are carried out and stress calculations shows considered diameter of 38mm is higher the required diameter of 34mm. Self-weight analysis and external load analysis are carried out to check the structural safety of the problem. Assembly is meshed with three dimensional solid elements and later fatigue analysis is carried out with 16 load cases. The results shows fatigue life is only 50% of permanent life Rotor dynamic analysis is carried out to find the unstable speeds in the operational range of 0 to 2000 rpm. The results shows unstable configuration in the problem. So an intermediate bearing is introduced to avoid the unstable speed along better fatigue life. The natural frequencies and stress generation mainly depends on support condition. So providing intermediate bearing helps in increasing the load carrying capacity along with dynamic stability for the problem.