Research On Hydro-viscous Soft Braking Device In High-power Downward Belt Conveyor

Through analyzing the braking process of high-power downward belt conveyor , this paper designs a new type of hydro-viscous soft braking device by use of the oil-film's shearing force between friction discs to transfer braking torque, according to the concrete requirement of this belt conveyor to braking device.The theoretical basis of hydro-viscous soft braking device is the technology on hydro-viscous drive (HVD); this article constructs a transmissible braking torque model at different frictional statuses of friction discs by the transmission mechanism. By studying the braking characteristics it comes to the conclusion that the system has better characteristic for speed when the change of friction discs' gap uses the changeable law of positive conic. This text gives some reduction measures according to the harm caused by towing torque, the calculation formula on oil-film's force condition between friction discs and the analysis of heat coming from the braking process of belt conveyor and heated situation of friction discs. After the comprehensive study on structure and material of friction discs of core components it presents the calculation method on the number of friction discs and its combination mode. Hydraulic system is divided into the controlling oil supply system and the lubrication and cooling system. Oil pressure and rotating speed use the closed loop control system taking on electrohydraulic proportional flooding valve as core. As the belt conveyor transfers energy into large of heat during the braking process inevitably, the paper gives the calculation formula of quantity of cooling oil.Finally, the paper designs a mechanical electrical and hydraulic control system containing belt conveyor, hydro-viscous soft braking device and all kinds of protection devices. It gives the flow diagram of control system at different conditions and puts up a test-bed for hydro-viscous soft braking device.