Design Of Vibration Isolator With Variable Stiffness And High Damping For Vehicle Engine

The high-power diesel engine has large vibration impact during the working process.In addition to reducing the vibration through engine structure optimization and innovation,how to optimize the design and match the engine vibration isolator to absorb vibration energy and reduce vibration transmission is one of the jamming problems that restrict the development of national defense equipment.This thesis proposes a new type of variable-stiffness and large-damping vibration isolator and carries out research on the design and test verification of the vibration isolator prototype to sovle the problem that a diesel engine has excessive vibration.The main research work and innovation are as follows:First,combined with the engine vibration suppression requirements under a series of typical working conditions,the stiffness and damping parameter matching analysis of the engine damping device was carried out and the overall configuration of a new high-loadlow stiffness-large damping vibration isolator suitable for high-power diesel engines was proposed.Secondly,in order to ensure the low stiffness vibration reduction and variable stiffness stabilization performance,according to the requirements of the vertical high load of the vibration isolator and the three-way variable stiffness parameter matching requirements,this thesis proposed the parallel configuration of the preloaded low stiffness main support spring and the V-shaped wire mesh three-way variable stiffness and designed the main support spring,V-shaped wire mesh and main bearing structure.Then,in order to solve the problem how to achieve large damping under multi-degreeof-freedom vibration and tight space constraints,a new configuration of a motion decoupling unidirectional large damping mechanism was innovatively proposed.The ring structure enables the piston-type damping mechanism to not only ensure the small gap required for large axial damping,but also eliminate the motion interference and wear problems of the damping mechanism caused by normal vibration.According to the matching requirements of damping parameters,a vertical and horizontal movement decoupling type unidirectional large damping mechanism of the vibration isolator was designed.Finally,a prototype with variable stiffness and large damping vibration isolator was developed,and its stiffness and damping characteristics were tested.A series of vibration suppression performance tests under typical operating conditions were carried out on the engine test bench.The engine vibration intensity was reduced by 11.0 mm/s,and the engine vibration intensity decreases by an average of 10.2 mm/s in the 1700～2200 rpm speed range.The engine vibration intensity was better than the index requirements under the 1300～2200 rpm speed.