Dynamics Research And Numerical Simulation Of Wet Multi Disc Brake

With increasing braking safety demands on engineering machinery in modern society, caliper disc brake and drum brake that are widely used on vehicles couldn’t meet the braking demands and there is a trend that they will be replaced by wet multi-disc brake. But wet multi-disc brakes don’t come for long, and the related theory is not complete. For the calculation of critical parameter, some are obtained by experience or equivalence, and the experimental research and actual measurement on its’actual value is not enough. The verification of wet multi-disc brakes is performed mainly by controlling temperature increase and pressure roughly meanwhile the application for controlling the distribution and size of temperature and stress in steel disc and braking disc is few. The corresponding works are done in this paper.The research object of this paper is a wet multi disc brake used on the underground LHD. Firstly, according to the underground LHD working conditions, the braking parameters for the wet multi disc brake are designed, and a three-dimension model is built in UG Then it is imported into ADAMS to build a virtual prototype model for dynamic analysis, then braking moment is obtained by defining a measuring function, it is close to the value that obtained by calculating. Secondly, a finite element model is constructed in ANSYS, which later is used for modal analysis on all parts of the wet multi disc brake, and the first12th modes are extracted to find its’natural frequencies and mode shapes, then it can be concluded that the working frequency is far more less than its’corresponding minimal frequency in all parts and resonance will not occur in all parts in working conditions. Later,a thermal coupling structure analysis for braking parts is conducted in ANSYS Workbench, only to find temperature and stress distribution in steel disc and braking disc are uneven, and that equivalent radius where higher stress and temperature exist is easiest part to craze. Finally, an analysis is conducted on temperature and stress distribution in steel disc and braking disc in repeated braking condition, it is concluded that temperature and stress in steel disc and braking will increase when a circulation is over and the D-value for maximal temperature and stress between two circulations is decreasing. The maximal stress will reach its’summit at166.35MPa and81.357MPa when the last circulation is over and maximal stress is within allowable stress for this material. Steel disc and braking disc can meet the demands in working time.The study in this paper provide reference for design of wet multi disc brakes and using wet multi disc brakes replacing caliper disc brakes and drum brakes, and it is of great value for practicability and engineering application.