Substantiation of the design of the magnetorheological damper of the motorcycle fork shock absorber
Students Name: Kovalchuk Ruslan-Andrian Bohdanovych
Qualification Level: magister
Speciality: Computer Engineering in Mechanical Engineering
Institute: Institute of Mechanical Engineering and Transport
Mode of Study: full
Academic Year: 2024-2025 н.р.
Language of Defence: ukrainian
Abstract: In cars, shock absorbers are a vital element of the entire suspension. Modern shock absorber designs use manual damping adjustment using manual switches. Thus, the suspension can be adjusted for a specific driver before the trip. However, these properties can no longer be changed while driving. In recent years, suspension designs have appeared that are able to change the damping even while driving. This is the Live Valve system from FOX. This system works on the basis of fast solenoid valves, it is not MR technology, but a passive electronically controlled suspension that adapts to the current situation. The system uses sensors to determine the current driving conditions, and then the control system decides whether the suspension should remain in hard mode or switch to soft mode. The control system can recognize four driving conditions: flat, uphill, downhill and free fall. Therefore, the development of a design of a magnetorheological damper of a motorcycle fork electric shock absorber is an urgent task of designing and modeling the parameters of a structure that would respond in real time to what is happening on the track and adapt almost instantly. The object of the research: force action on the elements of a magnetorheological damper of a motorcycle fork electric shock absorber. The subject of research: geometric and force parameters of the interaction of the elements of the magnetorheological damper of an electric shock absorber. The purpose of the research: development of a single-body magnetorheological electric shock absorber with a short response time, which is suitable for installation in a serially available front fork of a motorcycle. Passive damper, MR damper designs for single-track vehicles are considered. Existing methods of semi-active control of MR dampers are reviewed. Variants of modeling the characteristics of dampers and shock absorbers are considered. Research tasks are formulated. In the second section, the requirements that the magnetorheological damper of the electric shock absorber must meet are formulated. A technical functional analysis is carried out. The proposed MR shock absorber is single-body with a floating piston and a gas chamber. The conceptual design of the MR damper assembly consists of three structural assemblies of the MR valve: a magnetic core and a piston shell, a spool, a piston cover and a slot. The choice of the shock absorber concept was made for a shock absorber with a Hiperco 50 magnetic core, an all-steel 11SMn30 shell, a single coil and a slot, as well as curved grooves on the cover. This concept has the highest dynamic range and is cheap and easy to manufacture. The third section presents the designs of the 1st generation shock absorber, which will help to verify the mathematical models used and get feedback on individual structural components. The results and conclusions of the tests of the 1st generation shock absorber were used in the development of the final design solution of the 2nd generation lightweight shock absorber. In the first part, the MR valve of the shock absorber itself is designed, after which the design of the entire shock absorber, test results and design evaluation are described. The simulation of the F-v characteristic of the MR damper was carried out in its entire dynamic range from zero piston speed to high speed mode. The MRF 122EG fluid was selected for the MR valve. This MR fluid was chosen because of its low dynamic viscosity, since viscosity increases the damping force in the inactive state. Stress and strain simulations were performed. In the fourth section, an analysis of the strength of the MCE is carried out in the Autodesk Inventor program for components loaded with labor, for different materials for manufacturing elements. Low damping force in the off state is also important for semi-active steering. This is also affected by high passive resistances in the damper, so it exceeds the required value of 30 N. The damping force at a piston speed of 0.25 m/s is 43.3 N. The design solutions and relevant studies obtained in the work indicate their feasibility and practical use. Key words: magnetorheological fluid, damper, shock absorber, CAD system, maximum stress, maximum deformation.