Method of calculating the design parameters of the modulator anti-lock braking system with a high flow of working fluid

Abstract

The design dimensions of the executive hydraulic cylinders of the brake system of heavy-duty mining dump trucks cause high fluid flow during the braking process. Therefore, dimensions of the anti-blocking system modulator spool pair require unique electromagnets or hydraulic amplifiers to control. These solutions do not allow required modulator performance. A modulator scheme with division of the flow of fluid from the source to the brake cylinders was developed. This scheme allows during emergency braking passing an additional amount of fluid to cylinders through the valve, installed parallel to the main valve upon pressure increase phase and controlled by the pressure difference. The task is to develop a method for calculating the main structural dimensions of a modulator. The calculation of the valve of the second cascade, installed in parallel to the main stage, is carry out for the emergency braking mode with the maximum flow rate to ensure required performance of braking system. The balance of fluid flows equations are compile at the key points. The flow rate of the fluid through each of the valves is determine by the Torricelli formula, and the pressure difference across the valves is assume equals. The obtained relations allows to build a family of Q-p curves, which can be used to select the diameter and stroke of the additional valve depending on the flow rate in the brake system.