Automatic brake control apparatus and a brake pressure control valve

摘要

An automatic brake control apparatus includes a pressure intensifying solenoid valve in a hydraulic brake line connecting a source of hydraulic pressure with a brake, as well as a pressure reducing solenoid valve in a relief line branched from the brake line and connected to a low pressure reservoir. A pressure sensor is positioned to sense a hydraulic pressure in the brake line at a position downstream of a point where the relief line branches from the brake line. A controller receives a signal from the pressure sensor and determines desired brake pressure for producing a desired speed reduction rate. The controller outputs control signals to the pressure intensifying solenoid valve and the pressure reducing solenoid valve such that the detected brake pressure corresponds to the desired brake pressure. The apparatus may be incorporated into a brake pressure control valve having first and second stages.