Eaton Airflex DBB User manual

DBB 8104
Installation, Operation and Maintenance of
Airflex® DBB Brake Assembly with
Corrosion Protection
May, 1997
(Revised: January, 1998) PDF format
204138
 Copyright Eaton Corp., 1998, All rights reserved.
Caution:
Use Only Genuine AirflexReplacement Parts
The Airflex Division of Eaton Corporation recommends the use
of genuine Airflex replacement parts. The use of non-genuine
Airflex replacement parts could result in substandard product
performance, and may void your Eaton warranty. For optimum
performance, contact Airflex:
In Ohio: 800-233-5903
Outside Ohio: 800-233-5890
Warning
Forward this manual to the person responsible
for Installation, Operation and Maintenance of
the product described herein. Without access
to this information, faulty Installation, Operation
or Maintenance may result in personal injury or
equipment damage.

Table of Contents
1.0 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.2 How it Works . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2.0 INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.1 Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.2 Mounting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.3 Air Supply System . . . . . . . . . . . . . . . . . . . . . . . . . 4
3.0 OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
3.1 Pressure and Speed Limits . . . . . . . . . . . . . . . . . . . . . 5
3.2 Initial Operation . . . . . . . . . . . . . . . . . . . . . . . . . . 5
3.3 Periodic Maintenance . . . . . . . . . . . . . . . . . . . . . . . . 6
4.0 MAINTENANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
4.1 Wear Limits . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
4.2 Wear Adjustment & Disassembly . . . . . . . . . . . . . . . . . . 8
4.3 Friction Disc Replacement . . . . . . . . . . . . . . . . . . . . . 8
4.4 Cylinder Seal Replacement . . . . . . . . . . . . . . . . . . . . . 10
4.5 Spring Replacement . . . . . . . . . . . . . . . . . . . . . . . . 10
4.6 Bushing Replacement . . . . . . . . . . . . . . . . . . . . . . . 11
4.7 Assembly Procedures . . . . . . . . . . . . . . . . . . . . . . . 12
4.8 Corrosion Protection . . . . . . . . . . . . . . . . . . . . . . . . 12
5.0 ORDERING INFORMATION/TECHNICAL ASSISTANCE . . . . . . . . . . 13
6.0 PARTS LISTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
7.0 REVISIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
DBB8104 PDFformat ©Copyright Eaton Corp., 1998. All rights reserved.
(Revised: January, 1998)

Figure 1
TABLE 1
Item Description Item Description
2 Mounting Flange 24 Warning Decal
6 Stud 25 Name Plate
12 Clamp Tube 26 Drive Screw
14 Pressure Plate Sub-assembly 27 Spacer Tube
16 Spring Housing 28 Gear
17 Flat Washer 29 Wear Spacer
18 Lock Nut 31 Reaction Plate Sub-assembly
19 Cylinder 32 Decal Plate
20 Hex head Screw 34 Release Spring
21 Polypak seal 36 Hex Head Screw
22 Spring 53 Spring Retainer
23 Polypak Seal 101 Friction disc and ring gear sub-assembly
DBB8104 PDFformat 1© Copyright Eaton Corp., 1998. All rights reserved.
(Revised:January,1998)

1.0 INTRODUCTION
Throughout this manual there are a number
of HAZARD WARNINGS that must be read
and adhered to in order to prevent possible
personal injury and/or damage to the equipment.
Three signal words "DANGER", "WARNING",
and "CAUTION" are used to indicate the
severity of the hazard, and are preceded by
the safety alert symbol .
Denotes the most serious hazard,
and is used when serious injury or
death WILL result from misuse or
failure to follow specific instructions.
When serious injury or death
MAY result from misuse or failure to
follow specific instructions.
When injury or product/equipment
damage may result from misuse or
failure to follow specific instructions.
It is the responsibility and the duty of all
personnel involved in the installation, opera-
tion and maintenance of the equiment on
which this device is used to fully understand
the , and
procedures by which hazards are to be
avoided.
1.1 Description
1.1.1 The Airflex Model DBB brakes were
designed for heavy duty industrial
applications where spring set (power off)
braking is required.
1.1.2 All Airflex DBB brakes are supplied with long
wearing, NON-ASBESTOS friction material.
1.1.3 The spring housing (16) piston and cylinder
(19) are Nituff®coated, which is Teflon pene-
trated hard coat anodizing. The friction disc
assembly (101) is made out of steel and is
specially nitrided with a quench-polish-
quench system. The release springs (34) are
made from stainless steel and have flexible
polyurethane coating. The exposed cast sur-
faces are painted with multiple coats of
corrosion resistant paint. Bronze bushings
are provided in the reaction plate and pres-
sure plates to facilitate axial movement. The
clamp tubes (12) are made from aluminum-
bronze which provides high resistance to
wear and corrosion.
1.1.4 The rugged construction ensures long,
trouble free service. The corrosion protection
provided with these units will help prevent
premature failure when using in marine
environments. The iron components are
painted with a marine,two coat, epoxy coat-
ing. All other components are either coated
or manufactured with corrosion resistant
alloys.
1.2 How it Works
1.2.1 Referring to Figure 1, the gear (28) is
mounted on the shaft which is to be stopped
and the brake assembly is attached to the
machine frame or a reaction bracket. As air
pressure is applied through the ports in the
cylinder (19), the cylinder and pressure plate
(13), which are attached to each other with
screws (20), flat washers (17) and spacer
tubes (27), move away from the mounting
flange (1), which is connected to the
machine frame or reaction bracket. The
pressure plate compresses the springs (22)
against the stationary spring housing (16)
and the clamp force is removed from the
friction disc assembly (7) which rides on the
gear. The shaft is then free to rotate. As air
pressure is exhausted, the springs force the
pressure plate toward the mounting flange,
clamping the friction disc assembly between
the two members. On dual disc models, an
additional friction disc assembly and a
reaction plate (30) are clamped between the
pressure plate and mounting flange.
DBB8104 PDFformat 2© Copyright Eaton Corp., 1998. All rights reserved.
(Revised:January,1998)

Figure 3
Correct Track Incorrect Track
2.0 INSTALLATION
Use of commercial grade (Grade 2)
fasteners where Grade 8 fasteners
are specified may result in failure of
the fasteners and a sudden and
drastic reduction in brake torque.
Only qualified maintenance person-
nel should install, adjust or repair
these units. Faulty workmanship
will result in unreasonable expo-
sure to hazardous conditions or
personal injury.
Read these instructions thoroughly
and review until you fully under-
stand the installation sequence
before proceeding with the work
described in this section. Failure to
follow these instructions will result
in unreasonable exposure to hazard-
ous conditions or personal injury.
Do not paint the clamp tubes (12) or
the springs (34) as shown on Figure
1, as this may hinder the engage-
ment or disengagement of the brake.
NOTE: Airflex recommends guarding the
brake application. The guard should cover
the face and the entire outer diameter of the
unit.
2.1 Preparation
2.1.1 Figure 1 shows the relationship between the
brake mounting surface and the end of the
gear (dimension ".38" on Figure 1). The gear
is bored and keyed for a resulting Class
FN2S interference fit for inch shafting and
ISO System S7h6 for metric shafting.
2.1.2 Figure 2 show the mounting dimensions for
the brake to the machine frame or reaction
bracket.
20 DBB
(12) 0.656" (16.7)Ø
Mounting holes equally
spaced as shown on
22.000" (558.8) bolt circle.
Figure 2
5°
TABLE 2
Alignment Requirements
Brake
Size
Concentricity of
Shaft and Brake
in. (mm)
Perpendiculari
ty of
Mounting
Flange (1)
to Shaft in.
(mm)
20DBB 0.010 (0.25) 0.010 (0.25)
Perpendicularity referenced to outside diameter of
mounting flange from shaft center line (TIR).
DBB8104 PDFformat 3© Copyright Eaton Corp., 1998. All rights reserved.
(Revised:January,1998)

TABLE 3
Fastener Description and Assembly Torque ft-
lb (Nm) [Lubed]
Fastener 20DBB
Item #18 Description 3/4-10NC-3
Torque 150 (203)
Item #20 Description 3/4-10NC-2 Gr.
8
Torque 150 (203)
Item #36 Description 3/8-16NC-2 Gr.
8
Torque 40 (54)
Mounting
Screw Description 5/8-11NC-2 Gr.
8
Torque 138 (187)
2.1.3 Alignment
2.1.3.1 For proper operation and service life, the
brake reaction member must be aligned
to the shaft within the limits shown on
Table 2.
Proper alignment is necessary to
assure the friction discs track prop-
erly. Improper alignment will result
in excessive wear to the friction
material and its mating surfaces,
gear and ring gear. See Figure 3.
2.2 Mounting
NOTE: Prior to installing the brake, apply
100 psi air pressure releasing the spring
tension and slide the gear into the brake
assembly aligning the disc sub-assemblies,
exhaust the air to clamp them into position
and remove the gear.
Maximum allowable air pressure is
120 psig (8.2 bar). Application of
pressure exceeding maximum
allowable may result in damage to
the brake.
2.2.1 Ensure the shaft is free of nicks or burrs and
the ket fits properly in the shaft and gear.
Tap the key into the shaft keyway.
2.2.2 Apply a light coat of anti-seizing
compound to the shaft and key.
2.2.3 Press the gear onto the shaft, making sure
the dimension between the gear and the
brake mounting surface (".38") is main-
tained. See Figure 1 and . Heating the gear
uniformly to approximately 250oF (121oC)
will expand the bore and ease assembly.
2.2.4 Apply a light coat of MOLUB-ALLOY®412
ES grease to the gear teeth and pre fill the
groove in the friction disc splines as shown
on figure 4.Slide the brake assembly onto
the gear.
2.2.5 While supporting the brake, connect an
air supply and apply enough pressure to
release the brake. Attach the mounting
flange (1) to the brake mounting surface
using the appropriate fasteners. Torque the
fasteners to the specified value. See Table 3.
Use only the proper number and
grade fasteners shown in Table 4.
Use of commercial grade (Grade 2)
fasteners where Grade 8 fasteners
are specified may result in failure of
the fasteners and a sudden and
drastic reduction in brake torque.
Figure 4
DBB8104 PDFformat 4© Copyright Eaton Corp., 1998. All rights reserved.
(Revised:January,1998)

2.3 Air Supply System
Maximum allowable air pressure is
120 psig (8.2 bar). Operation of the
DBB at pressures exceeding 120
psig may result in damage to the
brake components.
Minimum releasing pressure for low
pressure brakes is 60 psig (4.1 bar)
and for high pressure brakes is 90
psig (6.1 bar). Operation at pres-
sures below minimum will result in
brake drag and excessive heat and
wear.
2.3.1 Since the air control arrangement will vary
from one application to the next, a specific
description cannot be presented here.
Following are some general guidelines for
installing the air control components.
2.3.1.1 Use full size piping consistent with the
control valve.
2.3.1.2 Keep the number of elbows to a minimum to
ensure consistent brake response.
2.3.1.3 Spool type solenoid valves are not
recommended. Use poppet type valves and
locate as close as possible to the brake.
If the DBB brake is being used on a
mechanical power press, special
valving may be required.
2.3.1.4 If the DBB brake is being used on a cyclic
application, an air receiver tank should be
installed in the air supply line and isolated
(check valve) from other air consuming
equipment.
2.3.1.5 The final connection to the brake inlet ports
must be made with flexible hose.
2.3.1.6 The DBB brake does not require lubricated
air; however the solenoid valve may.
Consult the valve manufacturer.
2.3.1.7 A pressure switch should be located in
the air supply line to the brake and
interlocked with the equipment electrical
controls.
3.0 OPERATION
3.1 Pressure and Speed Limits
3.1.1 Maximum applied pressure is 120 psig (8.2
bar). Minimum releasing pressure for low
pressure brakes is 60 PSIG (4.1 bar).
Minimum releasing pressure for high
pressure brakes is 90 psig (6.1 bar).
3.1.2 Maximum disc speed is 1800 RPM.
Operation at disc speeds exceeding
the maximum allowable, as shown
on Table 6, may result in exposure
to personal injury or product/equip-
ment damage.
3.2 Initial Operation
3.2.1 The non-asbestos friction material used on
DBB brakes may not develop rated torque,
as a short wear in period is required.
The non-asbestos friction material
used on Airflex DBB brakes may not
develop rated torque initially, as a
short wear in period is required.
Machine operation should therefore
be monitored closely until the
friction material wears in.
3.2.2 If the brake engagement appears harsh, a
flow control valve may be installed in the
brake air supply line. When using a flow
control valve, install so free flow is to the
brake and restricted flow is away from the
brake.
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(Revised:January,1998)

Excessive restriction of the brake
exhaust air will result in long stop-
ping times and inconsistent stop-
ping position.
3.2.3 If the DBB brake is used in combination with
a clutch, clutch/brake overlap may occur
which will result in excessive heat generation
and motor overload. Overlap may be
detected by monitoring the drive motor
current at the beginning and end of each
machine cycle. A current surge at the begin-
ning of the cycle usually indicates clutch
overlap which can be corrected by restricting
the air flow to the clutch or increasing the air
pressure to the brake. A current surge at the
end of the machine cycle usually indicates
brake overlap which can be corrected by
installing and adjusting a flow control valve
in the brake air supply line, as indicated in
3.2.2.
3.3 Periodic Inspection
3.3.1 As the friction material wears, the brake
torque will be reduced somewhat and
adjustment of the stopping position controls
(flow control or limit switch) will be neces-
sary. See table 4 for the friction material
wear limit.
3.3.2 Periodically check for air leakage in the area
of the cylinder seals (21,23). For
replacement, refer to the MAINTENANCE
section.
3.3.3 Periodically observe the friction disc
assembly(s) with the brake released.
Dragging friction discs may be caused by
wear or contamination at the gear/ring gear
contact areas.
3.3.4 Pneumatic and electrical control interlocks
should be periodically checked for correct
settings and operation.
3.3.5 Inspect for need for wear adjustment.
Refer to Section 4.2.
4.0 MAINTENANCE
Prior to performing any mainte-
nance on the DBB brake, make sure
the equipment is in, and will remain
in, a safe condition.
4.1 Wear Limits
4.1.1 Wear limits for the DBB components are
shown on Table 4. If any wear limit has been
reached or exceeded, that component must
be repaired or replaced.
4.2 Wear Adjustment & Disassembly
4.2.1 On both single and dual disc units, the
friction material must be replaced when worn
to the bottom of the groove on the friction
lining. See Figure 5. A wear adjustment is
required when the friction material is approxi-
mately one-half worn. To determine when
adjustment is required, measure the gap
between the spring housing (16) and the
pressure plate (13) with the brake engaged,
as shown on Figure 6. When this dimension
is .50" (12.7 mm) or greater, AND none of
the friction discs are worn to the bottom of
the wear groove, adjust per the following
procedure.
If a wear adjustment is not made,
the brake torque may deteriorate to
the point where the equipment will
not stop properly.
The Locknuts (18) must NOT be loos-
ened Unless air pressure is applied
tomrelieve spring pressure.
4.2.2 With 120 psi applied to the cylinder (19),
loosen and remove the locknuts (18) and
washers (17). Exhaust the air pressure.
NOTE: The socket size for locknuts (18) is
1 1/16" x 4" deep socket.
DBB8104 PDFformat 6© Copyright Eaton Corp., 1998. All rights reserved.
(Revised:January,1998)

TABLE 6
Wear Limits for DBB Brake Components
Item Description Wear Limit Remarks
#7
Friction Disc
Assembly Friction Material
Fully worn at bottom of dust
groove. See Figure 6.
Friction material must also be
replaced when contaminated
with oil or grease.
Dual disc brakes have adjustment
provision. See 4.2.1.
#1
Mounting
Flange
Friction Wear
Surface
Maximum wear is .03 1in.
(.80mm). Wear will be in form of circular grooves on iron surface.
#13
Pressure Plate
Friction Wear
Surface Maximum wear is .031 in.
(.80mm). Wear wil be in the form of circular grooves on iron surface.
Reaction Holes Maximum wear is .031 in. (.80mm). Wear will be in the form of elongation ofthe holes. Original hole diameters are shown on
the table below.
#30
Reaction Plate
Friction Wear
Surfaces Maximum wear (each Side)
is .031 in. (.80 mm). Wear will be in form of circular grooves on iron surface.
Reaction Holes Maximum wear is .031 in. (.80mm). Wear will be in the form of elongation ofthe holes. Original hole diameter is 1.343"
(34.11mm) .
#12
Clamp Tube Reaction Area Maximum wear is .015 in.
(.38mm). Wear will be in the form of a notch or step on the side of the tube.
#19
Cylinder Seal Area Maximum wear is .005 in.
(.13mm). Wear will be in the form of grooves where the seals contact.
#22
Spring Spring Free Height Minimum free height is 4.25"
(108mm). Springs must be
replaced in complete sets.
Original free height is 4.44/4.56"
(113/116mm)
#34
Release
Spring Spring Free Height Minimum free height is 1.5"
(38.1mm) Original free height is 1.67" (42.4mm).
#28 & #37
Gear and Ring
Gear Gear Backlash Maximum allowable total
backlash is .040 in.
(1.0mm).
Replace ring gear and gear together.
If step is worn in gear, gear must be
replaced.
Figure 5
Wear
Grooves
Figure 6
Measure this gap with
brake engaged.
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(Revised:January,1998)

4.2.3 Disconnect the air supply lines from the
brake.
4.2.4 Rig the cylinder assembly. Slide the
cylinder (19), spring housing (16) and
pressure plate (13) (powerpak) off of the
studs as an assembly. Set aside in a clean
area making sure not to damage the
friction material wear surface on the
pressure plate.
Note: If a stud (6) should happen to come
loose, remove it completely, clean the
threads on the stud and the threads in the
mounting flange. Apply Loctite®Primer
Grade "T" to the stud threads. After the
threads have dried, assemble to the mount-
ing flange using Loctite®#262. The end of
the stud must not extend past the mounting
surface on the mounting flange.
Loctite® #262 must be shaken prior
to application.
Loctite® #262 may irritate sensitive
skin. Refer to the product label for
proper safety precautions.
4.2.5 Remove the friction disc assemblies, the
reaction plates (30) and the release springs
(34) and set aside.
4.2.6 Slide the clamp tubes (12) and wear
spacers (29) off of the studs.
4.2.7 Inspect the friction disc for wear. Refer to
Table 4 for wear limits. Repair per section
4.3.
4.2.8 Inspect the friction wear surfaces on the
mounting flange and reaction plate surfaces.
if the limits in Table 4 are reached or
exceeded replacement is required.
4.2.9 Inspect the pressure plate wear surface. If
the wear reaches or exceeds then limit in
Table 4 replacement is required. Refer to
section 4.5 for further dis-assembly
procedures.
4.2.10 See section 4.4 for cylinder seal
replacement.
4.2.11 Inspect the clamp tubes, springs (22) and
release springs (34) and compare to the
limits in Table 4. If any limit is reached,
replacement is required.
4.2.12 Refer to section 4.5 if spring (22) (34)
replacement is required.
4.2.13 Re-assemble the brake per section 4.7.
4.3 Friction Material Replacement
4.3.1 Disconnect the air supply lines and remove
the cylinder/spring housing/pressure plate
assembly (power pac) per 4.2.2 -4.2.4..
4.3.2 Remove the friction disc assembly,
reaction plate, seperator springs and
remaining friction disc assembly and
transport to a clean work area.
4.3.3 Remove the screws and washers attaching
the friction disc subassembly to the ring gear
and remove the friction disc subassembly.
4.3.4 Thoroughly clean the threaded holes in the
ring gear and the threads on the screws.
4.3.5 Attach a new friction disc subassembly to
the ring gear using Loctite®#262 on the
screw threads. Torque the screws to the
value shown on Table 3.
Use only the proper size and grade
screws to attach the friction disc
sub-assembly to the ring gear. Use
of commercial (Grade 2) screws
where Grade 8 screws are specified
may result in failure of the screws
and a sudden loss of brake torque.
4.3.6 Friction disc cores may be relined with
new friction material per the following
instructions. Refer to Table 5 for the
appropriate friction disc replacement kit
part number.
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(Revised:January,1998)