pins of the self-adjusting mechanism, and rests against
the insulators installed in the outer ends of the brake
pistons. It is the component through which force is
directly transmitted during application and release of
the brakes. The wear plate is keyed to the torque tube to
prevent rotation of the complete subassembly, and
serves as the friction surface for the outer face of the
adjacent rotating disc. The wear plate insulator
prevents brake heat from being transferred to the
pressure plate and the brake pistons.
The brake pistons transmit hydraulic pressure
through the pressure plate subassembly to the brake
discs. Standard O-rings and backup rings around each
piston prevent hydraulic fluid leakage and entry of
contaminants. The pistons are further protected against
heat transfer from the pressure plate subassembly by
individual insulators installed in the ends of each
piston where it contacts the pressure plate.
1.
Bleeder valve
7.
Pressure plate subassembly
Self-adjusting mechanisms are located around the
2.
Rotating disc
8.
Brake inlet port
brake housing. They accomplish normal release of the
3.
Stationary disc
9.
Self-adjusting mechanism
brake and provide a continuing adjustment action to
4.
Housing backplate
10.
Brake housing subassembly
compensate for brake wear. Each mechanism consists
5.
Keyed torque tube
11.
Brake assembling bol
of a self-adjusting pin, a spring housing and bushing, a
6.
Torque tube spacer
return spring guide, a retaining ring, a grip and tube
subassembly, and a self-locking nut. The grip and tube
Figure 14-32.--Trimetallic brake assembly.
subassembly mounts over the self-locking pin, with the
grips being installed firmly on the tube. As disc wear
occurs, automatic adjustment is provided by
Description
movement of the adjusting pins through the split collar
The brake housing subassembly, keyed torque tube
grips. The retaining ring inside the spring housing
and spacer, and the housing backplate are bolted
serves as a stop and retainer for the spring guide,
together to form the basic brake assembly. The
which, in turn, holds the return spring in position. The
head of the self-adjusting pin engages the pressure
remaining components of the brake assembly are
plate subassembly to allow brake release when
mounted over the keyed torque tube and between the
pressure is removed.
brake housing and the housing backplate. The
metallic-faced rotating discs have keyways that engage
Operation
drive keys in the wheel so that they rotate with the
wheel.
When the landing gear wheel is rotating, the
The rotating discs are separated by the stationary
metallic-faced rotating discs of the brake assembly
discs, which are keyed to the torque tube. The mating
rotate freely between the stationary steel discs. When
surfaces of these rotating and stationary discs
pressure is applied to the brake assembly pistons, the
constitute the major friction-braking surfaces of the
rotating and stationary discs are forced together,
brake. Additional friction surfaces exist between the
creating friction between their surfaces. The amount
outer face of one rotating disc and the housing
of hydraulic pressure applied to the brake pistons is
backplate, and between the outer face of the rotating
controlled by the aircraft's brake metering system in
disc at the opposite end and the pressure plate
response to the operating of the brake pedals. Braking
subassembly.
action applied to the wheel brake is proportional to the
pressure exerted on the brake pedal.
The pressure plate subassembly consists of the
pressure plate, replaceable wear plate, and wear plate
Pressure applied to the brake actuates all of the
insulator. These three parts are riveted together. The
pistons within the brake housing. These pistons, in
pressure plate serves as a seat for the self-adjusting
turn, force the pressure plate subassembly laterally
14-34
