ANALYSIS OF BRAKE SYSTEMS IN MOTOR VEHICLES USING PRACTICAL EXAMPLES FROM THE ASPECT OF THEIR DIAGNOSTICS
Authors: Stefanovic Slobodan , Mladenovic Stefan 
Published: November 2022

The part of the braking system that has the task of transmitting the command activated by the driver to thebrakes is called the transmission mechanism. The transmission mechanism itself can be different depending on howit is constructed and conceptually executed. As for the conceptual solution, the question arises as to whether thetransmission method itself must be such that the driver's command is only transmitted to the brakes or the driver'scommand itself is handed over to a separate energy system. The energy system itself can be such that it additionallyhelps the activation of the brakes (servo brake force boosters) or completely takes over the activation of the brakes,with the creation of a certain braking force on the wheels, and these are the so-called mechanisms with full servoaction. Today we have the following transmission mechanisms in use: Mechanical transmission, hydraulic with orwithout servo amplification, hydraulic with full servo action, pneumatic with full servo action, hydro-pneumaticwith servo amplification or with full servo action. The very choice of these systems depends on a large number offactors, but the main one is - how much energy must be delivered to the brakes. Each of these systems is explainedseparately in the paper. A mechanical transmission mechanism is a system that does not have any additional servoamplification, but the command of the driver or the person operating the machine is directly transmitted to thebrakes. Based on this, we can conclude that the application of this transmission mechanism in brake systems is quitelimited. Today, this transmission mechanism is only used as a service brake on some slower trucks and tractors. Thehydraulic transmission mechanism is the system that is most common in brake systems of passenger, light cargo anddelivery vehicles. In the case of vehicles weighing up to 1000 kg, the driver alone is sufficient to develop thenecessary energy for braking, so it is not necessary to additionally support the braking force with servo boosters. Butthat's why smaller trucks and delivery vehicles need additional help from a servo booster to activate the brakingforce. Servo amplifiers have become an integral part of the equipment in passenger vehicles primarily due to thesafety, security and comfort of passengers. In contrast to the mechanical transmission, this system is morecomplicated in terms of performance and its operation is based on the transmission of pressure through the brakefluid from the main brake cylinder to the brake cylinder in the brakes. The pressure created by the brake fluid actson the pistons in the cylinder itself and in this way force is created and the brakes are activated. The main advantageof this system is the very safety and safer braking, because with the hydraulic system it is possible to make adistribution in several independent branches to the cylinders on the brakes, and this is one of the basic satisfactoryrequirements in the ECE regulation that the brakes must also have an auxiliary braking system in case dismissal ofthe principal. The system itself consists of: the pedal, which is activated by pressing the foot on the pedal itself, themain brake cylinder, the distribution system, the working brake cylinders in the brakes and the brake itself.