9.1. Features of a design
Cars Chevrolet/Daewoo Lanos are equipped by two independent brake systems: working and lay. The first, equipped with a hydraulic drive, provides braking at the car movement, the second затормаживает the car on parking. Working system two-planimetric, with diagonal connection of brake mechanisms of forward and back wheels. One contour of a hydrodrive ensures functioning right forward and left back of brake mechanisms, another — left forward and right back.
At refusal of one of contours of working brake system other contour providing a stop of the car with sufficient efficiency is used.
The vacuum amplifier and pressure regulators are included in a hydraulic drive in hydrodrives of back brakes.
The lay brake system has тросовый a drive on brake mechanisms of back wheels.
|Fig. 9.1. The brake mechanism of a forward wheel: 1 – brake колодки; 2 – a support of the brake mechanism; 3 – directing колодок; 4 – a brake disk; 5 – a directing finger of a support; 6 – the valve of release of air; 7 – a brake hose
The brake mechanism of forward wheels disk, with automatic adjustment of a backlash between колодками
1 (fig. 9.1
) and a disk 4, with floating скобой
. Mobile скоба
it is formed by a support 2 c the one-piston working cylinder. Directing 3 колодок
it is attached by bolts to a rotary fist. Mobile скоба
it is attached by bolts to the directing fingers 5 established in apertures directing колодок
. Directing fingers are greased консистентной
by greasing and protected by rubber covers. In a cavity of the wheel cylinder the piston with a sealing ring is established. At the expense of elasticity of this ring the optimum backlash between колодками
and the ventilated disk which surface is protected by a brake board is supported. At braking the piston under the influence of pressure of a liquid presses internal pad
to a disk, as a result of force of reaction the support moves on fingers and external колодка
too nestles on a disk, thus force of pressing колодок
appears identical. At растормаживании the
piston at the expense of elasticity of a sealing ring is taken away from колодки
, between колодками
and a disk the small backlash is formed.
The main brake cylinder
|Fig. 9.2. The main brake cylinder with pressure regulators in hydrodrives of brake mechanisms of back wheels and a tank: 1 – the main brake cylinder; 2 – a tank of the main brake cylinder; 3 – a stopper of a tank with the gauge of level of a brake liquid; 4 – connecting plugs; 5 – pressure regulators in hydrodrives of brake mechanisms of back wheels
1 (fig. 9.2
) type "tandem" of a hydraulic drive of brakes consists of two separate chambers connected to independent hydraulic contours. The first chamber is connected with right forward and left back the brake mechanisms, the second — with left forward and right back.
On the main cylinder through rubber connecting plugs 4 the tank 2 which internal cavity is divided by partitions into three compartments is established. Each compartment feeds one of chambers of the main brake cylinder and the main cylinder of a drive of deenergizing of coupling.
By pressing a pedal of a brake pistons of the main brake cylinder start to move, working edges of cuffs block compensatory apertures, chambers and a tank are separated and replacement of a brake liquid begins.
In a stopper 3 tanks the gauge of level of a brake liquid is established. At falling of level of a liquid below admissible in a combination of devices the alarm lamp of failure condition of brake system lights up.
The vacuum amplifier
), established between the mechanism of a pedal and the main brake cylinder, at braking at the expense of depression in an inlet pipe of the engine through a rod and the piston of the first chamber of the main cylinder creates the additional effort proportional to effort from a pedal.
In a hose connecting the vacuum amplifier with an inlet pipe, the return valve is established. It keeps in the amplifier depression at its falling in an inlet pipe and interferes with hit топливовоздушной to a mix in the vacuum amplifier.
Regulators of pressure
5 (fig. 9.2
), established on the main brake cylinder, correct at braking pressure of a brake liquid in back brake mechanisms, excepting possibility of advancing blocking of back wheels. It is reached by proportional reduction of pressure in a hydrodrive of brake mechanisms of back wheels in relation to pressure in a hydrodrive of brake mechanisms of forward wheels. The parity of values of pressure in forward and back working cylinders at various values of effort to pedals is resulted in tab. 9.1.
Table 9.1 the Parity of values of pressure in contours of a hydrodrive of the brakes, supported by pressure regulators
The brake mechanism of back wheels
drum-type, with automatic adjustment of a backlash between колодками
and a drum. Brake колодки
1 and 11 (fig. 9.4
) are put in action by one hydraulic working cylinder 8 with two pistons. The optimum backlash between a drum and колодками
is supported by the mechanical regulator 6 established on распорной
to a lath 9.
|Fig. 9.4. The brake mechanism of a back wheel: 1 – a lobby brake колодка; 2 – a board of the brake mechanism; 3 – a spring of the lever of a regulator of backlashes; 4 – basic racks; 5 – the lever of a regulator of backlashes; 6 – a regulator of backlashes; 7 – the top coupling spring; 8 – the working cylinder; 9 – распорная a lath; 10 – разжимной the lever of a drive of a lay brake; 11 – back brake колодка; 12 – a cable of a drive of a lay brake; 13 – the bottom coupling spring
The lay brake
put in action mechanically, consists of the lever established on the basis of a body between forward seats, a forward cable with the adjusting device and the equalizer to which two back cables are attached, and also разжимных
levers 10 (fig. 9.4
), the back wheels established in brake mechanisms.
The lay brake does not demand special leaving. At operating repair check up degree of deterioration of teeths of sector and the doggie. Excessively worn out details replace.
At detection of breakage of covers or delays of cables it is necessary to replace their new.
The working course of a pedal of a brake at the working engine should be about 60–65 mm. Too small working course testifies to wrong initial installation of a pedal of a brake, infringement of adjustment of the vacuum amplifier of brakes or jamming of the working cylinder, causes the raised expense of fuel and the accelerated deterioration brake колодок. Too big working course — a sign of backlashes above permitted standard in the mechanism of a pedal or infringement of tightness of a hydrodrive of brake system. If the working course decreases by numerous pressing a pedal, i.e. it becomes more rigid", in system air. If the pedal full speed starts to increase, system негерметична.
If at braking the brake pedal always starts to vibrate, most likely, brake disks are jarred on. Unfortunately, in their such situation it is necessary to change only, and at once both.
If at braking the car starts to pull aside, check up working cylinders: probably, their replacement is required.
If in a forward suspension bracket there was a knock vanishing at braking, check up an inhaling of bolts of fastening of a support.
After replacement brake колодок prior to the beginning of movement necessarily some times press a brake pedal — pistons in working cylinders should rise into place.