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» Pneumatic Disc Brake SL7 - SM7
DESCRIPTION AND FUNCTION
3.2 Description of Operation
(Floating caliper principle)
During actuation, the push rod of the actuator (18) moves
the lever (19). The input forces are transferred via the
eccentric roller bearing (20) to the bridge (17). The force is
then distributed by the bridge (17) and the two threaded
tubes (16) to the tappet and boot assemblies (13) and finally
to the inboard pad (12¹).
After overcoming the running clearance between the
inboard pad (12¹) and the brake disc (46), the reaction forces
are transmitted by the caliper to the outboard pad (12²). The
clamping forces on the pads and the disc (46) generate the
braking force for the wheel.
Brake Actuation
Brake Release
After releasing the air pressure, the return spring (27) pushes
the bridge (17) with the threaded tubes and lever (19) back
to the start position.
Brake Adjustment
The so called running clearance of the disc brake is the air
gap between the brake pad (12) and the brake disc (46). This
distance is necessary to achieve a free running (and therefore
unbraked) disc when the brakes are in a ‘non applied’ state.
Too large a running clearance can lead to a greater braking
distance.
The designated running clearance is so designed to
compensate for changes under typical use such as:
- expansion of parts due to high temperatures.
- viscoelastic effect of the brake pads.
- finish and runout tolerances of a brake disc and possible
lip development.
To ensure a constant running clearance between pads and
disc, the brake is equipped with a non-wearing, automatic
adjuster mechanism. The adjuster (23) operates with every
cycle of actuation due to the mechanical connection with
lever (19).
As the pads and disc wear, the running clearance increases.
The adjuster (23) and turning device (24) turn the threaded
tubes (16) by an amount necessary to compensate for this
wear.