Key Technology Research Of ZPU Grease Pump

Nowadays, centralized lubrication system plays an increasingly significant role withthe tendency of large-size and intelligentization of mechanical equipment. The lubricatingproperty is in direct relation to the efficiency of the mechanical equipment. As a majorelement of the lubricating system, the grease pump also determines the performance andlife of the lubricating system. In engineering applications, abrasion failure often happenedin the contact area between shaft sleeve and the chute. And this article mainly aims at thisproblem.Firstly, the dynamic characteristics of the ZPU grease pump is analyzed, which tellsus the motion principle of the pump. Secondly, the stress of the bushing and the chute iscalculated by means of the Hertz formula. Also, to verify the accuracy of the theoreticalresults, finite elements analysis is ran to solve the same problem by using software AnsysWorkbench. It shows that the theoretical results and the simulation results have highlyconsistence. The conclusion is, under the precondition of existing materials and structuresize, when the pressure of the pump reached to30MPa, the maximum equivalent stress onthe chute surface exceeds the allowable contact stress. Meanwhile, the simulation resultshows that the hardness of the substrate is not enough, so extra heat-treatment is needed tostrengthen the hardness of the substrate. The lubricating condition is analyzed by using theelastohydrodynamic lubrication theory, and the minimum film thickness is calculated, theresult shows proved that the frictional pair is in boundary lubrication condition.According to the Hertz formula, the increasing of the radius of the collar can producepositive effect to reduce the contact effective. Thus, theoretical calculation and finiteelement simulation are carried out again, which proves that the method is reasonable. Inaddition, analyses of frictional stress shows that the frictional stress under rollingcondition is much less than it under sliding condition. So, in case of not ensuring themovement between the shaft sleeve and the chute, it is necessary to replace the shaftsleeve with a rolling bearing.