Research On Drag And Meshing Characteristic Of Wet Brake On Off-road Axle

Wet Multi Disc Brake(WMDB) on off-road axle is widely used in the construction machinery braking system, because of its long service life, anti-heat fading characteristic, strong anti-pollution ability, good heat dissipation and low cost of repair. But the wet brake system installation require high accuracy, system in the main structure and using parameters will have an important impact on the brake characteristics. In addition, during braking process, the brake will also produce oil temperature rise and the drag torque increase phenomenon, will seriously affect the performance of automobile, such as deteriorating the automobile braking stability, reducing the life of some parts. The research subject is based on the scientific and technological key project of Chongqing Dajiang Xinda Vehicle Corporation, “Research on the key technologies of the wet axle”. It is wet brake on off-road axle that have been taken as an object of study. With static and dynamic pressure lubrication theory of flow and Navier-Stokes equation, finally get the influence law of each critical parameter with drag and meshing characteristics of wet brake on off-road axle.The main research work of this paper are as follows:(1)In order to improve the braking meshing characteristics of wet multi disc brake on off-road axle, based on wet multi disc brake in the special condition of brake oil liquid, this paper built the engaging characteristics model of paper based friction material. According to the Patir-Cheng part of the flow dynamic pressure average flow model, this paper will use the paper base material permeability characteristics, the compressive strain and the asperity contact model into the brake engagement model. In addition, in the calculation of temperature conduction formula will also consider the process of cooling liquid drop viscosity, the influence law of the discussion and analysis of paper based friction material in wet brakes on permeability of off-road axle wet brake meshing characteristics.(2)Aiming at the characteristics of wet brake with drag phenomenon in non braking operation process, in order to study the drag characteristics of off-road axle wet multi disc brake operation and braking process, through the brake groove surface distribution characteristics and the oil film shrink phenomenon and laminar flow Navier-Stokes equation considering the into the new wet brake with drag characteristic prediction system. In addition to the new drag torque prediction system, the influence of volume flow rate, viscosity, the gap parameters to wet brakes drag torque and temperature change laws were studied.(3)Taking a certain type of off-road axle wet brake as the object and build test bench, the test bench for installation check test and load temperature detection, finally to different oil temperature and different speed of off-road axle wet brake torque measurement. Test through the calculation of the theoretical results and bench test data analysis, research methods for off-road axle wet brake with a drag and meshing characteristics of the proposed reliability verification.