9.1. Features of a design

Fig. 9.1. Scheme of a hydraulic actuator of brakes: 1 – brake mechanism of a forward wheel; 2 – flexible hose of a forward brake; 3 – the contour pipeline left forward – right back brakes; 4 – main cylinder of a hydraulic actuator of brakes; 5 – the contour pipeline right forward – left back brakes; 6 – tank of the main cylinder; 7 – vacuum amplifier; 8 – brake mechanism of a back wheel; 9 – flexible hose of a back brake; 10 – pressure regulator; 11 – brake pedal

The car is equipped with the double-circuit working brake system with diagonal division of contours (fig. 9.1) that considerably increases safety of driving of the car. One contour of a hydraulic actuator ensures functioning right forward and left back brake mechanisms, another — left forward and right back.
At refusal of one of contours of the working brake system the second contour providing a car stop with sufficient efficiency is used.
The hydraulic drive switched on the vacuum amplifier 7 and the double-circuit regulator 10 of pressure of back brakes.
The parking brake system has the drive on brake mechanisms of back wheels.

The vacuum amplifier (fig. 9.2) of diaphragm type works by the principle of pressure difference in vacuum and atmospheric cameras owing to what when pressing a pedal of a brake the additional effort to the piston of the main brake cylinder is created. A rubber diaphragm 8 together with the case 17 of the valve divide a cavity of the vacuum amplifier into two cameras: vacuum And yes atmospheric Century. The camera A is connected to an inlet collector of the engine via the backpressure valve of a tip and a hose.
Valve case 17 plastic. At the exit from a cover it is condensed with a corrugated protective cover 11. The rod 2 drives of the main cylinder with the basic plug, the piston 10, the valve 15 assembled, returnable springs 13 and 14 according to a pusher and the valve, a pusher 12 is placed in the case of the valve.
By pressing a pedal the pusher 12, the piston 10, and after them and the valve 15 against the stop moves to a valve case saddle. At the same time cameras A and B are separated. At further movement of the piston its saddle departs from the valve and through the formed gap the camera B connects to the atmosphere. The air which arrived through a gap between the piston and the valve and also on channel D, creates pressure upon a diaphragm 8. At the expense of pressure difference in cameras A and B the case of the valve moves together with a rod 2 which affects the piston of the main cylinder.
At the released pedal the valve 15 departs from a saddle of the case and through the formed gap and the channel From the camera A and B are reported among themselves.
The regulator of pressure changes pressure in the hydraulic drive of brake mechanisms of back wheels depending on load of a back axis of the car. It is included in both contours of the brake system, through it brake fluid arrives to both back brake mechanisms.

Fig. 9.2. Vacuum amplifier: 1 – flange of fastening of a tip; 2 – rod; 3 – returnable spring of a diaphragm; 4 – sealing ring of a flange of the main cylinder; 5 – main cylinder; 6 – hairpin of the amplifier; 7 – case of the amplifier; 8 – diaphragm; 9 – cover of the case of the amplifier; 10 – piston; 11 – protective cover of the case of the valve; 12 – pusher; 13 – returnable spring of a pusher; 14 – valve spring; 15 – valve; 16 – rod buffer; 17 – valve case; And – the vacuum chamber; In – the atmospheric camera; With, D – channels

The regulator of pressure of 1 (fig. 9.3) is attached to an arm by 9 two bolts 2 and 16. At the same time the forward bolt 2 at the same time fixes also a bifurcate arm 3 levers 5 of the drive of the regulator of pressure. On a finger of this arm the pin 4 pivotally fixed the dvuplechy lever 5. His top shoulder is tied with the elastic lever 10 which other end through an earring 11 is pivotally connected to an arm of the lever of a back suspension bracket.
The arm 3 together with the lever 5 at the expense of oval openings under a bolt of fastening can be moved concerning pressure regulator and by that to regulate effort with which the lever 5 affects the regulator piston.

Fig. 9.3. Pressure regulator drive: 1 – pressure regulator; 2, 16 – bolts of fastening of the regulator of pressure; 3 – pressure regulator drive lever arm; 4 – pin; 5 – pressure regulator drive lever; 6 – pressure regulator drive lever axis; 7 – lever spring; 8 – body arm; 9 – arm of fastening of the regulator of pressure; 10 – elastic lever of the drive of the regulator of pressure; 11 – earring; 12 – earring bracket; 13 – washer; 14 – lock ring; 15 – arm finger; And, In, With – openings

Fig. 9.4. Pressure regulator: 1 – pressure regulator case; 2 – piston; 3 – protective cap; 4, 8 – lock rings; 5 – piston plug; 6 – piston spring; 7 – case plug; 9, 22 – basic washers; 10 – sealing rings of a pusher; 11 – basic plate; 12 – pusher plug spring; 13 – ring sealing valve saddles; 14 – valve saddle; 15 – sealing laying; 16 – stopper; 17 – valve spring; 18 – valve; 19 – pusher plug; 20 – pusher; 21 – piston head sealant; 23 – piston rod sealant; 24 – cap; And, D – the cameras connected to the main cylinder; In, With – the cameras connected to wheel cylinders of back brakes; Е – channel of a supply of brake fluid; To, M, N – gaps

In the regulator there are four cameras: And yes D (fig. 9.4) are connected to the main cylinder, In — to the left wheel cylinder of back brakes, With — with right.
In a starting position of a pedal of a brake the piston 2 is drawn in by the lever 5 (see fig. 9.3) through a lamellar spring 7 to a pusher 20 (see fig. 9.4) which under the influence of this effort is drawn in to a saddle of the 14th valve 18. The valve 18 is wrung out from a saddle, gaps To (between a head of the piston and a sealant 21) and N are as a result formed. Through these gaps of the camera A and D are reported with cameras B and C.
By pressing a brake pedal liquid through gaps To and the N and cameras B and C comes to wheel cylinders of brake mechanisms. At increase in pressure of liquid the effort on the piston seeking to nominate him from the case increases. When the effort from pressure of liquid exceeds effort from the elastic lever, the piston will begin to start from the case, and after it under the influence of springs 12 and 17 the pusher 20 together with the plug 19 and rings 10 will begin to move. At the same time the gap of M increases, and gaps of N and To decrease. When the gap of N is chosen completely and the valve 18 isolates the camera D from the camera C, the pusher 20 together with the details located on it ceases to move after the piston. Now pressure in the camera C will change depending on pressure in the camera B. At further increase in effort to brake pedals pressure increases in the D, V and A cameras, the piston 2 continues to start from the case, and the plug 19 together with sealing rings 10 and a plate 11 under the amplifying pressure in the camera B moves towards a stopper 16. At the same time the gap of M will begin to decrease. Due to reduction of volume of the camera About pressure in it, so, and in the drive of a brake accrues and it will be almost equal to pressure in the camera B. When the gap To becomes equal to zero, pressure in the camera B, so, and in the camera C pressure will grow in the camera A at the expense of a liquid drosselirovaniye between a head of the piston and a sealant 21 to a lesser extent, than. Dependence between values of pressure in cameras B and A is defined by the relation of a difference of the areas of a head and a rod of the piston to the area of a head.
At increase in loading of the car the elastic lever 10 (see fig. 9.3) is loaded more and the effort from the lever 5 increases by the piston, i.e. the moment of a contact of a head of the piston and a sealant 21 (see fig. 9.4) is reached with a bigger pressure in the main brake cylinder. Thus, efficiency of back brakes with increase in loading increases.
At refusal of a contour of brakes the left forward — right back sealing rings 10 and the plug 19 under the influence of liquid pressure in the camera B will be displaced towards a stopper 16 against the stop of a plate 11 in a saddle 14. Pressure in a back brake will be regulated by a part of the regulator which includes the piston 2 with a sealant 21 and the plug 7. Work of this part of the regulator, at refusal of the called contour, is similar to work at serviceable system. The nature of change of pressure at the exit of the regulator same, as well as at serviceable system.
At refusal of a contour of brakes the right forward — the left back pusher 20 with the plug 19, sealing rings 10 under the influence of pressure of brake fluid is displaced towards the piston, nominating him from the case. The gap of M increases, and the gap of N decreases. When the valve 18 concerns a saddle 14, growth of pressure in the camera C stops, that is the regulator in this case works as pressure limiter. However the reached value of pressure is enough for reliable work of a back brake.
In the case of 1 regulator of pressure the opening closed by a cap 24 is executed. The liquid leak from under a cap at its expression testifies to leakage of rings 10.

Fig. 9.5. Main cylinder: 1 – cylinder case; 2, 3 – pistons of the drive of contours of brakes; 4 – expansion washer; 5 – pusher

The main cylinder two-section, with a consecutive arrangement of pistons (fig. 9.5). On the case of the main cylinder the tank 6 (see fig. 9.1) is fixed in which bulk mouth the sensor of emergency level of brake fluid is installed. Sealing rings of high pressure and a ring of the back wheel cylinder are interchanged.

Brake mechanisms of forward wheels

Fig. 9.6. Brake mechanism of a forward wheel: 1 – brake disk; 2 – guide of blocks; 3 – support; 4 – protection cover; 5 – working cylinder; 6 – brake hose; 7 – valve of production of air; 8 – the directing finger; 9 – a protective cover of the directing finger; 10 – brake shoes
disk, with automatic adjustment of a gap between blocks and a disk, with a floating bracket. The bracket is formed by a support of 3 (fig. 9.6) and the wheel cylinder 5 which are pulled together with bolts. The mobile bracket is attached by bolts to fingers 8 which are established in openings of a guide of 2 blocks. In these openings lubricant is put, between fingers and a guide of blocks rubber covers 9 are established. To grooves of a guide brake shoes 10 are drawn in by springs.
In a cavity of the cylinder 5 the piston with a sealing ring is installed. Due to elasticity of this ring the optimum gap between blocks and a disk is supported.

The brake mechanism of a back wheel (fig. 9.7) drum, with automatic control of a gap between blocks and a drum. Brake shoes 1 and 6 are put in action by one hydraulic working cylinder 9 with two pistons.

Fig. 9.7. Brake mechanism of a back wheel: 1 – brake shoe back; 2 – lever of the drive of the parking brake; 3 – lower coupling spring of blocks; 4 – board of the brake mechanism; 5 – cable of the drive of the parking brake; 6 – brake shoe forward; 7 – the directing spring; 8 – razzhimny level; 9 – working cylinder; 10 – top coupling spring of blocks; 11 – finger of the lever of the drive of the parking brake

Fig. 9.8. Working cylinder: 1 – block emphasis; 2 – protective cap; 3 – cylinder case; 4 – piston; 5 – sealant; 6 – basic plate; 7 – spring; 8 – crackers; 9 – persistent ring; 10 – persistent screw; 11 – union; And – a cut on a persistent ring

The device of automatic control of a gap is located in the working cylinder. Its basic element is the cutting persistent ring of 9 (fig. 9.8) established on the piston 4 between a fillet of the persistent screw 10 and two crackers 8 with a gap of 1,25-1,65 mm.
Persistent rings 9 are inserted into the cylinder with the tightness providing effort of movement of a ring on a cylinder mirror not less than 343 N (35 kgfs) that exceeds effort on the piston from coupling springs 3 and 10 (see fig. 9.7) brake shoes.
When because of wear of slips the gap of 1,25-1,65 mm completely is chosen, a fillet on the persistent screw 10 (see fig. 9.8) nestles on a fillet of a ring 9 owing to what the persistent ring moves after the piston at a wear size. With the braking termination pistons by effort of coupling springs move against the stop crackers in a fillet of a persistent ring. Thus, the optimum gap between blocks and a drum is automatically supported.

The parking brake system with the mechanical drive affects brake mechanisms of back wheels. The drive of the parking brake consists of the lever 2 (fig. 9.9), adjusting draft 4, the equalizer 5, a cable 8, the lever 2 of the manual drive of blocks and a razzhimny level 8 (see fig. 9.7).

Fig. 9.9. Drive of the parking brake system: 1 – button of fixing of the lever; 2 – lever of the drive of the parking brake; 3 – protective cover; 4 – draft; 5 – cable equalizer; 6 – adjusting nut; 7 – lock-nut; 8 – cable; 9 – cable cover

Sensor of emergency level of brake fluid of mechanical type. The case 2 (fig. 9.10) of the sensor with a sealant 4 and the basis 3 with a reflector 6 are drawn in by a tightening ring 5 to a tank mouth end face.
Through an opening of the basis there passes the pusher 7 connected to a float 9 by means of the plug 8. On a pusher the mobile contact 11 is located, and on the case of the sensor there are motionless contacts 10. The cavity of contacts is pressurized by a protective cap 1.
At decrease in level of brake fluid in a tank to maximum permissible the mobile contact falls by motionless contacts and closes a chain of a lamp of the alarm system in a combination of devices.

Fig. 9.10. Sensor of emergency level of brake fluid: 1 – protective cap; 2 – sensor case; 3 – sensor basis; 4 – sealing ring; 5 – tightening ring; 6 – reflector; 7 – pusher; 8 – plug; 9 – float; 10 – motionless contacts; 11 – mobile contact