Bendix Commercial Vehicle Systems SB-7 AIR DISC BRAKE - Manual (Page 11)

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3.2 Description of operation
(Floating Caliper principle)
3.2.1 Brake actuation
During actuation, the Push Rod of the Actuator (18/1
or 18/2) moves the Lever (19). The input forces are
transferred via the Eccentric Bearing (20) to the
Bridge (17). The force is then distributed by the
Bridge (17) and the two Threaded Tubes (16) to the
Tappets (13) and finally to the inboard Pad (12).
After overcoming the running clearance between the
Pads and the Rotor, the reaction forces are transmit-
ted to the outboard Pad (12). The clamping forces on
the Pads (12) and the Rotor (46) generate the braking
force for the wheel.
3.2.2. Brake release
After releasing the air pressure, the two Return
Springs (27/28) push the Bridge (17) and Lever (19)
back to the start position; this ensures a running
clearance between Pads and Disc is maintained.
3.2.3 Brake adjustment (automatic)
To ensure a constant running clearance between
Disc and Pads, the brake is equipped with a low
wearing, automatic adjuster mechanism.
The Adjuster (23) operates with every cycle of actua-
tion due to the mechanical connection with Lever
(19). As the Pads and Disc wear, the running clea-
rance increases. The Adjuster (23) and Turning
Device (24) turn the Threaded Tubes (16) by an amo-
unt necessary to compensate for this wear. The total
running clearance (sum of clearance both sides of
Disc) should be between 0.03 and 0.04 in. (0.6 and
0.9 mm.; smaller clearances may lead to overheating
problems.