4-2
FULL POWER HYDRAULIC BRAKE
FULL POWER HYDRAULIC BRAKE
SYSTEM
SYSTEM
ADVANTAGES
ADVANTAGES - The full power hydraulic
brake system has several advantages over
traditional brake actuation systems. These
systems are capable of supplying fluid to a
range of very small and large volume
service brakes with actuation that is faster
than air brake systems. Figure represents
a time comparison between a typical air/
hydraulic and full power hydraulic brake
actuation system.
Full power systems can supply significantly
higher brake pressures with relatively low
reactive pedal forces. The reactive pedal
force felt by the operator will be proportional
to the brake line pressure being generated.
This is referred to as brake pressure
modulation.
Another key design feature of full power
systems is the ability to control maximum
brake line pressure. In addition, because
these systems operate with hydraulic oil,
filtration can be utilized to provide long
component life and low maintenance
operation.
Because these systems are closed center,
by using a properly sized accumulator,
emergency power-off braking that is
identical to power-on braking can be
achieved. These systems can be either
dedicated, where the brake system pump
supplies only the demands of the brake
system or non-dedicated, where the pump
supplies the demands of the brake system
as well as some secondary down stream
hydraulic device.
Another important note is that all seals
within these system must be compatible
with the fluid medium being used.
Response time
Response time
Full power brake actuation VS
Full power brake actuation VS
Air/Hydraulic brake actuation
Air/Hydraulic brake actuation
Br
ak
e torque(lb
·
in)
1000
900
800
700
600
500
400
300
200
100
Time(seconds)
Brake torque
(Full power)
Brake torque
(Air/hydraulic)
Brake pressure
(Full power)
Brake pressure
(Air/hydraulic)
0
1
2
3
4
Summary of Contents for HL955
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