7.3.1 Description of the circuits of the brake system
What to do in case if the hydraulic drive of the brake system is depressurized and the brake fluid starts leaking under pressure? This is a very dangerous situation: you press the brake pedal, and it falls through, the car does not even start stopping. In order to protect the driver from such an unpleasant situation and to preserve the ability to brake, even with a partial loss of efficiency, the hydraulic drive was divided into contours, thus creating a spare braking system, which is often called emergency.
Note
In case of a leak and, as a consequence, depressurization of a single circuit, which is fed, for example, through the left hole in the master cylinder, the left piston, having pushed out liquid through a break of the line, will rest the extension cord on the bottom of the cylinder, thus creating a fictitious bottom in the right working cavity. In case if the depressurization occurs in the circuit, which is fed from the right cavity, the right piston, displacing the fluid, will rest the extension cord on the left piston, transmitting force to it from the rod.
There are several layouts for dividing the hydraulic drive of brakes into circuits. All of them are shown in Figure 7.13. The most common are shown in Figures A and B. The figure indicates that the front (1) and rear (2) cavities of the master brake cylinder are each responsible for their own circuit, separating or duplicating the hydraulic drives of the front and rear brakes.
Figure 7.13 Different layouts of dividing the hydraulic drive into circuits.
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