ANALYSIS OF BRAKE SYSTEMS IN MOTOR VEHICLES USING PRACTICAL EXAMPLES FROM THE ASPECT OF THEIR DIAGNOSTICS

Abstract

The part of the braking system that has the task of transmitting the command activated by the driver to the
brakes is called the transmission mechanism. The transmission mechanism itself can be different depending on how
it is constructed and conceptually executed. As for the conceptual solution, the question arises as to whether the
transmission method itself must be such that the driver's command is only transmitted to the brakes or the driver's
command itself is handed over to a separate energy system. The energy system itself can be such that it additionally
helps 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 servo
action. Today we have the following transmission mechanisms in use: Mechanical transmission, hydraulic with or
without servo amplification, hydraulic with full servo action, pneumatic with full servo action, hydro-pneumatic
with servo amplification or with full servo action. The very choice of these systems depends on a large number of
factors, but the main one is - how much energy must be delivered to the brakes. Each of these systems is explained
separately in the paper. A mechanical transmission mechanism is a system that does not have any additional servo
amplification, but the command of the driver or the person operating the machine is directly transmitted to the
brakes. Based on this, we can conclude that the application of this transmission mechanism in brake systems is quite
limited. Today, this transmission mechanism is only used as a service brake on some slower trucks and tractors. The
hydraulic transmission mechanism is the system that is most common in brake systems of passenger, light cargo and
delivery vehicles. In the case of vehicles weighing up to 1000 kg, the driver alone is sufficient to develop the
necessary energy for braking, so it is not necessary to additionally support the braking force with servo boosters. But
that's why smaller trucks and delivery vehicles need additional help from a servo booster to activate the braking
force. Servo amplifiers have become an integral part of the equipment in passenger vehicles primarily due to the
safety, security and comfort of passengers. In contrast to the mechanical transmission, this system is more
complicated in terms of performance and its operation is based on the transmission of pressure through the brake
fluid from the main brake cylinder to the brake cylinder in the brakes. The pressure created by the brake fluid acts
on the pistons in the cylinder itself and in this way force is created and the brakes are activated. The main advantage
of this system is the very safety and safer braking, because with the hydraulic system it is possible to make a
distribution in several independent branches to the cylinders on the brakes, and this is one of the basic satisfactory
requirements in the ECE regulation that the brakes must also have an auxiliary braking system in case dismissal of
the principal. The system itself consists of: the pedal, which is activated by pressing the foot on the pedal itself, the
main brake cylinder, the distribution system, the working brake cylinders in the brakes and the brake itself.