construction of the brake disc - indian railway · between brake disc and brake pads not parallel....
TRANSCRIPT
INTRODUCTION
The Axle Mounted Disc Brake System has been provided in LHB design
Mainline Passenger Stock for Indian Railways.
The brake system equipment provided on the LHB design coaches meet the
requirement for high-speed trains hauled by locomotives and permits the
emergency braking for such trains to be within the stipulated limits when
brakes are applied on a straight trac at a speed of 160 kmph with loco brakes.
DESIGN
The axle mounted brake disc consists of a friction ring and a hub that
are connected together and secured in place by nine screw connections.
FUNCTION
The brake caliper closes when the brake cylinder is actuated with
compressed air. The brake pads come into contact with the brake
disc, the braking effect begins.
The axle-mounted brake disc which rotates with the wheelset axle
is braked according to the pad
SPECIFICATION:
Dimension - 640 mm x 110 mm;
Brake Radius 247 mm
Type - Axle shaft mounted
concentrically split,
Material - Grey cast iron
Friction ring
wear (allowed) = 7 mm max.
Weight = 126 kg
.
ABOUT BRAKE DISC:
Internally vented axle mounted brake disc
Good heat dissipation and high braking performance
No maintenance required
Wear checks/limits:
No hair, incipient crack or through cracks permitted on
Hub/connected flange:
Incipient cracks on Disc:
<72.5 mm, apart by 50 mm min. permitted propagating
between two edges.
<70 mm, apart by 50 mm min permitted propagating
from the edges.
Scoring upto 1mm allowed.
Concave wear up to 2 mm allowed.
Residual thickness up to 14 mm of disc friction surface.
Slanting wear up to 2mm allowed.
Permitted for breakage of 4 fins max. alternatively.
Construction of the brake disc The below two picture depicts the cross section of the brake disc for
better understanding.
Checking procedure
Safety and operational safety regulations
The axle-mounted brake disc has been built according to the state of-
the-art and recognized safety regulations. Nevertheless during its use it
may constitute a risk to the health and life of the user or third parties
and/or damage the device and other physical resources. The axle-mounted brake disc may only be used in a technically perfect
condition and for its intended purpose, paying attention to safety, risks
and the operating manual In addition to this instruction, you must observe and apply the binding
general statutory and other regulations on accident prevention and
environmental protection. The personnel commissioned to work with the axle-mounted brake disc
must read the maintenance instructions and particularly chapter with
safety instructions before starting work. Use personal safety equipment. Ensure that brakes (Service or Parking) are off before any operation
and the vehicle is over the pit for ease of checking.
Traceability
Before taking up any checking activity, ensure that the following
traceability data are collected and noted.
1. Zonal railway
2. Coach no.
3. Coach type
4. Commissioning date
5. POH date
6. Wheel Sl.no. (if visible)
7. Axe Sl.no. (if visible)
8. Axle position no. (Starting from Non Power Pack end)
9. Disc position - LHS (or) RHS of axle (LHS on Non Power Pack
side)
10. Disc Serial no. (if visible)
11. Photos of the Disc in case of abnormalities found
12. Caliper + Actuator assembly - FT/KB
13. Checked by
14. Any other observations
To be used Tools
Calibrated Torque wrench (20 - 100 Nm range)
Socket for M12 nut (suitable for use in torque wrench)
Torch Light for better visibility
Hand held mirror (for clear view of disc closer to wheel)
Wiping cloth
Steel brush (to be profiled suitable for better accessibility)
Orientation of fixing numbers
Cracks in Lugs of friction pair
Clean all sides of lug area (both nut and bolt head sides)
thoroughly to remove dirt particles.
Visual check for cracks / incipient cracks of lugs of the friction ring on
both sides of the disc (nut and bolt head side)
Note: If cracks are detected in any of the lug, the disc has to be taken
out of service immediately
Check for Wheel shelling (deep pit / shelling marks)
Visually check for any pitting marks all around the wheel tread.
In case deep pit / shelling marks are found, make a note of the same and inform to
Shed authorities to replace the axles.
Check for Tightening torque
To be carried out only if there is a visible loosening of nut is observed.
If any such cases are witnessed, the below mentioned procedure is to
be followed.
Warning: Brake disc must have cooled down. Risk of injury from
burns when touching the hot brake disc.
> If parts are missing, replace parts according to part list.
> Maximum two non — complete fixings permitted. If more
detected the disc must be replaced.
> Set torque wrench at 50Nm.
> Tighten M12 nuts using torque wrench (diagonally
opposite).
> Stop when you hear the "Click" sound. Do not over
tighten anymore.
> Make torque marking (on each nut, washer and segment).
Ensure that the torque mark color is different from the
existing one.
Part list fixing parts:
Part name Part no.
Segment D 128332-400
Bolt D 128599-200
Lock nut D 001754-101
Spring washer D 002651-101
TYPE OF DEFECTS
Penetrating crack, one-sided
Penetrating crack, both sides
Incipient cracks
Surface cracks
Scoring
Hollow wear
Splintering
Hot spots
Definition of Cracks
Type of Crack Defintion Figure Penetrating
cracks
Penetrating cracks are
cracks (fractures) that
reach from the inner to the
outer diameter of a
frictional ring side and
penetrate this over the
entire cross-section.
Type
of
Crack
Defintion Figure
Incipi
ent
crack
s
Incipient cracks are cracks in the frictional
surface that begin at the inner
or outer diameter of the friction ring and
penetrate the friction ring
side locally.
Surfa
ce
crack
s
Surface cracks are cracks in the frictional
surface that do not penetrate
the friction ring side in an axial direction.
Checking Parameters
S No Determining the
actual condition
Evaluation/measures
1 Wear marks on
friction ring.
The wear marks must be visible .Pay
attention to hollow wear & scoring
2 Hollow wear and
scoring in the
frictional surfaces.
The permissible values for the hollow wear
are 1.0
mm and for the depth of scoring 1.0 mm.
3 Splintering in the
frictional surfaces.
Unacceptable; replace friction ring.
4 Cracks.
4.1 Cracks in the
hub
Unacceptable; replace axle-mounted brake
disc.
4.2 Cracks in the
connection &
screw
connection areas
of hub & friction
ring.
Unacceptable; replace axle-mounted brake
disc.
4.3 Cracks in the
frictional
surfaces.
Crack definitions
4.3.1 Penetrating
cracks.
Unacceptable; replace friction ring.
4.3.2 Incipient cracks. Unacceptable; replace friction ring.
4.3.3 Surface cracks. a) Permissible up to a length of 50 mm, when
the inner or outer edge is reached.
b) Permissible up to a length of half the friction
ring width if the gap to the inner or outer edge
is at least 10 mm. Surface cracks may not be
more than of 0.5 mm width.
4.4 Cracks in the
cooling fins.
Permissible on max. 2 cooling fins. Bet.
Cooling fins with permissible cracks there
must be at least 3 undamaged cooling fins
5 Foreign bodies
in cooling ducts.
Remove foreign bodies and clean cooling ducts
6 Hot spots Permissible.
7 Missing or loose
fastening, screws
and segments.
Unacceptable.
8 Loose friction
rings.
Unacceptable; check tight fit through visual
check
and shaking the friction ring. Tighten loose
friction ring.
Troubleshooting table The most common problems are listed in the following troubleshooting
table. Other combinations of faults are possible.
Fault Possible cause Remedy/measures
Development
of smoke
during
braking
(annoying
smell).
• Preservative not
removed before
commissioning.
• Frictional surfaces
dirtied by oil or the
like.
• None.
• Check the brake disc/pads;
determine the cause and
remedy
Air slot
between brake
disc
and brake pads
not parallel.
• Friction ring loose.
• Brake caliper stuck or
defective brake
cylinder
• Check: shake the friction
ring
• Check the fastening
elements, complete if
necessary. Tighten all
screws to the specified
tightening torque.
Scoring in the
frictional
surfaces
of the brake
disc.
• Foreign body or brake
disc abrasion has
gone into the brake
pad material.
• Non existence of
brake pads.
• Replace pads.
• Face friction rings if depth
of scoring unacceptable.
• Replace pads; check the pad
holder lock, replace the pad
holder if necessary.
Hot spots on
the frictional
surfaces of the
brake disc
(overheating).
• Pad material
unacceptable
• Unequal contact
pattern of brake pads.
• Driving with the brake
on.
• Overloading of
vehicle
• (axle load to high).
• unacceptable pressure
in
• brake cylinder.
• Check the pad type; fit
specified brake pads.
• Check hollow wear. Reduce
by overturning if necessary.
• Release the service and
spring applied brake. Check
brake control; repair if
necessary.
• Adjust the journey profile to
the permissible
specifications.
Above-
average
cracking.
• Overload on brake
disc.
• Check whether the journey
profile or design parameters
are still correct for the brake
(e.g. higher weights,
deceleration, etc..); correct if
necessary.
• Check whether the damage
was caused by a blocking
brake cylinder or if the
vehicle was driven with the
parking brake on; remedy the
cause.
• Overload on disc brakes by
train driver (disuse of
brakes).
Uneven wear
on the two
frictional
surfaces of a
brake
disc.
• Blocking brake caliper
• or defective brake
cylinder.
• Unequal energy input
• in brake disc.
• Different grades of
pads.
• Check the brake caliper, repair
if necessary.
• Check the operability of the
brake cylinder, replace if
necessary.
• Check the brake gap with the
brake released.
• Check hollow wear. Before
installing new brake pads
remove any unacceptable
hollow wear.
• Fit the specified pad material.
Disclaimer:
It is clarified that this pamphlet does not supersede any existing provisions laid down
by RDSO, Railway Board or Zonal Railways. The pamphlet is for guidance only and it is not a
statutory document.
If you have any suggestion or comment, please write to:
Director (Mech), CAMTECH, Maharajpur,Gwalior (M.P.) – 474 005
Ph.0751-2470890, Fax 0751-2470841
(For Official Use Only)
PAMPHLET on
Instruction for Axle Mounted Brake
Disc in LHB Coach (FTIL Type)
Hkkjr ljdkj GOVERNMENT OF INDIA
jsy ea=ky; MINISTRY OF RAILWAYS
CAMTECH/M/GWL/2014-15/Beake Disc/1.0
Sept 2014
egkjktiqj, Xokfy;j & 474 005
Maharajpur, GWALIOR - 474 005