Analysis And Study Of Mechanical Properties On The Key Structure Of Hydraulic Damper

Hydraulic shock absorber is an important constituent of railway vehicle suspension system. Its damping characteristic plays a very important role in the steadiness and comfort of running train. Foreign hydraulic shock absorbers are more mature in production and application, and they have the proper structure size for different kinds of shock absorbers. Foreign hydraulic shock absorbers hold most market of high-speed train hydraulic shock absorbers in our country by their superior performance. While native shock absorber industry started late and our products perform shoddily when compared with foreign products. Structural strength shortage is a very important reason. Therefore, reliability analysis of the key parts of shock absorber has important meaning to enhancing quality of our native hydraulic shock absorbers.This dissertation introduces working principle and structure of hydraulic shock absorber firstly, and takes the product of Lince Group Hydraulic Damper Co.Ltd as research object. It analyses the key parts of the shock absorber structure and takes preliminary calculation of structure size. On this basis, focused on the following aspects:(1)Analyses and simulates stress distribution and section deformation of thick wall annulus which suffering radial concentrated force, and analyzes stress distribution of two common structures and the influence of dimensions on stress and deformation. The result shows that the stress of annulus with pull of press has certain relation, and the radial section deforms uneven with concentrated force, the first place where plastic deformation happened may change with the of the size of the circle fittings.(2)Analyzes the force that connection joint sleeve suffered, establishes model of sleeve and analyses the influence of different force with finite element based on ANSYS Workbench. Deduces the reason of plastic deformation of sleeve, offers proper opinions of structure of sleeve, and compares the effects of different schemes. The simulation results show that the damping force and welding residual stress effects reliability of sleeve mostly and the increase of radial dimensions improves better than the increase of axial dimensions.(3)Summarize the pretightening force calculation formula of piston rod thread connection in elastic or plastic fastening and calculation formula of pretightening moment to provide a reference for pratical production, analyses stress distribution of thread connection, analyses the influence of structure factors on connection strength and the reason why the thread looses. The results show that the relief groove is dangerous section of shock absorber thread connection, pitch and groove depth will affect the scope of preloaded force which thread can get, the increase of the groove width can reduce stress concentration, the bigger the preloaded force works in elastic deformation range the better, the smaller the preloaded force work in plastic deformation range the more reliable and the former shows better characters of loose than the latter.