6.1.5. Brake mechanism of a back wheel

Fig. 6.7. Brake mechanism of a back wheel: 1 – nut of fastening of a nave; 2 – wheel nave; 3 – lower coupling spring of blocks; 4 – brake shoe; 5 – the directing spring; 6 – wheel cylinder; 7 – top coupling spring; 8 – razzhimny level; 9 – finger of the lever of the drive of the parking brake; 10 – lever of the drive of the parking brake; 11 – board of the brake mechanism

Fig. 6.8. Wheel 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

Drum, with automatic control of a gap between blocks and a drum (fig. 6.7). The device of automatic control of a gap is located in the wheel cylinder. Its basic element is the cutting persistent ring of 9 (fig. 6.8) 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 shift 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 7 (see fig. 6.7) 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. 6.8) 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.