Brake system diagram
1 – a protective casing of a forward brake; 2, 18 - pipelines connecting two front brake caliper cylinders; 3 - support; 4 – hydraulic drive reservoir; 5 - stoplight switch; 6 – parking brake lever; 7 - adjusting eccentrics of the right rear brake; 8 - fitting for bleeding the hydraulic drive of the rear brakes; 9 - pressure regulator; 10 - stop signal; 11 - rear brake wheel cylinder; 12 - the lever of the manual drive of the pads and the expansion bar; 13 - adjusting eccentric of the left rear brake; 14 - brake shoe; 15 - rear cable guide; 16 - guide roller; 17 - brake pedal; 19 - fitting for bleeding the hydraulic drive of the front brakes; 20 - brake disc; 21 - master cylinder
This brake system has two circuits that provide independent drive of the front and rear wheel brakes. Both circuits are powered by the same pedal 17 (see fig. Brake system diagram), which, using a bracket, is attached together with the clutch pedal to the front panel of the body.
In addition to the brake pedal, the hydraulic drive includes, in addition to the brake pedal, the main brake cylinder 21, the reservoir 4 of the master cylinder, the rear brake pressure regulator 9, the brake mechanisms of the front and rear wheels together with the working cylinders and pipelines.
Master brake cylinder
The brake master cylinder is attached to the clutch and brake pedal bracket. Pistons 3 and 5 (see fig. Hydraulic brake master cylinder) activate different circuits. Both pistons take their initial position under the action of springs 8, which press the pistons all the way into the screws 7. The tightness of the pistons in the cylinder is ensured by four sealing rings 6. The body is closed with a plug 1 in front.
Pedal assembly
Pedals 6 (see fig. Clutch and brake pedal bracket parts) and 19 are suspended on the bracket 1 by means of an axle made in the form of a bolt.
Axis 18 is fixed with nut 2 in the holes of the cheeks of the bracket. On the axis between the cheeks of the bracket and the distance sleeve 7, the inner sleeves 4 and 14 of the clutch and brake pedals are clamped. Pedals are pivotally mounted on these bushings, in the hubs of which outer bushings 5 and 9 are pressed in. Pushers 20 are pivotally attached to both pedals, acting on the pistons of the hydraulic cylinders. The reverse travel of the clutch pedal is limited by the buffer 11 mounted on the head of the bolt 12. The main cylinders of the clutch release drive and the brake drive are attached to the bracket shelf.
Pressure regulator
Regulator 9 is connected to the rear brake drive circuit (see fig. Brake system diagram) pressure, which corrects the pressure in the rear brake drive depending on the position of the body relative to the rear axle beam, i.e. depending on vehicle load. It acts as a restrictor valve, automatically cutting off the flow of brake fluid to the rear brakes, reducing the chance of rear wheel skidding when braking.
The regulator is mounted on the body bracket and connected to the rear axle beam through the torsion lever 12 (see fig. Pressure Regulator Drive Parts) and thrust 7. The other end of the torsion lever acts on the piston 10 (see fig. Rear brake pressure regulator in non-working position).
Fluid enters cavity A from the master cylinder, and from cavity B it exits into the wheel cylinders of the rear brake drive.
The force P acting on the piston from the torsion lever increases as the body approaches the axle beam and decreases as the body moves away from the rear axle beam.
Before the pressure regulator begins to act, piston 10 abuts against plug 6 under the action of force P and spring 9. In this case, gaps are formed through which cavities A and B communicate, i.e. the pressure in them will be the same and equal to the pressure in the hydraulic brake drive.
When the brakes are applied, the rear of the car rises by inertia and, consequently, the pressure on the piston from lever 1 decreases. The force of fluid pressure on the upper end of the piston with a larger surface area at some point exceeds the pressure force of the fluid acting on the piston from below, and the piston will go down until it stops in the seal 7. At the same time, the cavities A and B will be separated, and different pressures will be created in them: in the cavity A, the pressure Pa will be equal to the pressure in the master cylinder, and in the cavity B, the pressure Pv will be less by the value that determines the balance of the piston, which is under the action of pressure Pa and Pb, spring 9 and the force of the torsion lever. Thus, partial or complete separation of cavities A and B by piston 10 regulates the braking torque on the rear wheels.
Front wheel brake
The brake mechanism of a forward wheel is disk. It consists of the ones shown in Fig. Front wheel brake (Front wheel brake caliper parts) calipers 12 (4) complete with working cylinders 17, brake disc 18, two brake shoes 16 (11), connecting fingers 8 (8) and pipelines.
The caliper is attached to the bracket 11 with two bolts 9, which are locked by bending the bolts of the locking plates to the edge. The bracket 11, in turn, is attached to the flange of the steering knuckle 10 together with the protective cover 13 and the rotary lever. The caliper has a radial groove through which the brake disc 18 passes and two transverse grooves for accommodating brake pads 16. The lugs of the caliper have two windows with guide grooves in which two opposite cylinders 17 are installed. To fix the cylinders relative to the caliper, a spring lock is installed in the cylinder 4, included in the side groove of the caliper.
Each cylinder has a piston 3 (1), which is sealed with an elastic rubber ring 6 (3). It is located in the groove of the cylinder and tightly compresses the surface of the piston. The cylinder cavity is protected from contamination by a rubber cap 7 (2).
The working cavities of the cylinders are interconnected by a pipeline 2 (5). Fitting 1 is screwed into the outer cylinder (6) for bleeding the front brake drive circuit, to the inner one - a hose fitting for supplying brake fluid.
The piston 3 rests against the brake pads 16, on which the pads 5 are glued. The pads are mounted on the fingers 8 and are pressed against them by springs 15 (7). Pins 8 are held in the cylinder by cotter pins 14 (9).
The brake disc 18 is attached to the wheel hub with two dowel pins.
Rear wheel brake
The brake mechanism of a back wheel of drum type, with self-adjusting pads. Brake pads 3 with lining 7 (see fig. Rear wheel brake), wheel cylinder 1 and other parts are mounted on the brake shield, which is attached to the flange of the rear axle beam. A package of plates is attached to the bottom of the shield with two rivets, one of which is a support for the lower ends of the brake pads. To regulate the gap between the shoes and the drum, eccentrics 8 are used, on which the shoes rest under the action of the coupling springs 5 and 10.
In building 4 (see fig. Wheel cylinder parts) wheel cylinder, there are two pistons 2, which are bursting by spring 7 with support cups 5. Seals 3 are pressed against the end of the pistons by the same spring.
Stops are pressed into the pistons, into the grooves of which the upper ends of the brake pads rest. The outlet of the pistons from the cylinders is sealed with rubber caps 1. To bleed the rear brake drive, a fitting 6 is screwed into the cylinder.