Research On Cushioning Mechanism Of A New Type Hydraulic Shock Absorber

In modern industry，the application of more and more automatic machinescauses much impact between moving parts. In order to ensure the smooth movementand extend the life of mechanism, shock absorbers have been widely used. Amongvarious types of shock absorbers, the hydraulic shock absorbers gradually get thefavor, because of its advantages, such as smooth deceleration, large buffer capacity,high buffering efficiency and long life. Compared to other countries, domesticresearches on hydraulic shock absorber are late, immature and not clear. So, thispaper studies the core shaft hydraulic shock absorber. The main work of the paper isbelow:(1) Analyzed main structures, proposed key performance parameters of coreshaft hydraulic shock absorber and the design requirements of structures. Based onthe ideal model of hydraulic shock absorbers, researched the function of dampingforce and stroke, the function of the throttle area with other structural parameters.Analyzed the clearance flow and fitting accuracy between inside and outside cylinderbarrels. Obtained calculating method for offset spring to choose metal spring andcompressed gas spring. Showed the choice principle of hydraulic oil, includingqualifications that hydraulic oil should have and characters of various hydraulic oil.(2) Detailed analyzed the forces of moving parts, including impact confined part,cylinders and isolating piston. Established the math model of core shaft hydraulicshock absorber by the application of Newton’s laws and hydrodynamic equations.Used the software of MATLAB to achieve numerical simulation of shock absorbers,obtained the buffer characteristic curves under different situations, which providebasics of the design of the buffer’s key parameters and critical structures.(3) Achieved simulation of throttle, which is determined factor of hydraulicshock absorber, the simulation objects consist3kinds throttles, including rectangle,triangular and semicircular. By the application of FLUENT, consists of preprocessor,solver and postprocessor, established the model of3throttles, completed simulationunder same conditions, which provided data about oil pressure, oil velocity and oiltemperature. According the simulation, chose the best kind of throttles. (4) Established the3D model of hydraulic shock absorber, achieved thesimulation of internal flow field with FLUENT dynamic mesh, and gain theconclusion of internal flow of the hydraulic shock absorber, include: the form of fluidflow, the regulation of pressure in the working chamber, the interaction relationshipbetween the highest pressure, oil velocity and throttling core shaft diameter, thedistribution of throttles, finally find out the optimal solution.