URAL Motorcycles 4320M, Руководство по эксплуатации, Страница: 64 / 321

63
1-hydraulic body; 2-hydraulic piston; 3-hydraulic seal; 4-lining wear indicator; 5-wear indicator washer; 6-
indicator housing; 7,10-contact springs; 8-air piston; 9-air cylinder; 11-casing; 12-rod; 13-drain tube; A-
clearance when linings are worn; I-booster servo system
Figure 47 - Wabco Air-Over Hydraulic Booster
When pressing the clutch pedal liquid pressure from the master cylinder is transferred
through the pipelines to the air-over hydraulic booster, where it impacts the hydraulic piston 2,
air-over hydraulic booster and the piston 1 (see figure 48) of the servo system.
Under the servo system piston the air piston 2 (see figure 48) moves and impacts the ser-
vo system valve 5. The valve opens air feed to the air cylinder 9 (see figure 13), the air-over hy-
draulic booster increasing booster rod 12 force to the clutch release fork. Incoming air pressure is
changed with the servo device automatically depending on the force applied by the driver to the
clutch pedal.
After pedal release booster liquid pressure falls down, servo system air valve closes, air-
over hydraulic booster piston returns to its initial position.
Through the contact spring the piston 8 (see figure 47), booster with the rod 12 are always
connected backlash-free with clutch fork, with the coupling, the diaphragm spring and contact
clutch plate. When clutch linings are worn out backlash-free connection provides following of lin-
ing wear by the booster piston - when wearing the piston goes deeper inside the booster and im-
pacts the lining wear indicator.
Wear indicator 4 is extending more and more under the piston impact, the indicator wash-
er 5 extends away from the indicator body 6, and when the clearance between the washer and the
body becomes 23 mm, lining wear is critical and it is necessary to replace the linings urgently or
to replace the driven disc assembly.