U.S. patent application number 12/196511 was filed with the patent office on 2010-02-25 for reactive sintering to eliminate metal inserts in carbon-carbon brake discs.
Invention is credited to Mark L. La Forest, Alexander Mukasyan, Allen H. Simpson, Gregory Vanderheyden.
Application Number | 20100044170 12/196511 |
Document ID | / |
Family ID | 41163744 |
Filed Date | 2010-02-25 |
United States Patent
Application |
20100044170 |
Kind Code |
A1 |
Simpson; Allen H. ; et
al. |
February 25, 2010 |
REACTIVE SINTERING TO ELIMINATE METAL INSERTS IN CARBON-CARBON
BRAKE DISCS
Abstract
A brake disc rotor or stator is manufactured with slots in the
interior face of the disc. A paste comprised of a fine powder of a
carbide-forming metal along with fine carbon powder, suspended in
an organic binder, is applied to the force-bearing areas in the
rotor slot faces or the stator slot faces. The disc is then placed
into a furnace in a nitrogen atmosphere and heated to the ignition
temperature. When the furnace reaches the ignition temperature, a
combustion reaction begins that creates a molten liquid ceramic
material on the slot face. Upon cooling, the resulting brake disc
has a tough, hard, abrasion-resistant ceramic surface on the
portion of the brake disc slot that bears pressure.
Inventors: |
Simpson; Allen H.;
(Buchanan, MI) ; La Forest; Mark L.; (Granger,
IN) ; Vanderheyden; Gregory; (South Ben, IN) ;
Mukasyan; Alexander; (Granger, IN) |
Correspondence
Address: |
HONEYWELL INTERNATIONAL INC.
Law Department AB 2, P.O. Box 2245
Morristown
NJ
07962-9806
US
|
Family ID: |
41163744 |
Appl. No.: |
12/196511 |
Filed: |
August 22, 2008 |
Current U.S.
Class: |
188/218XL ;
419/9 |
Current CPC
Class: |
F16D 69/025 20130101;
F16D 2250/0053 20130101; F16D 2200/0039 20130101; F16D 65/126
20130101; F16D 65/127 20130101; F16D 65/125 20130101 |
Class at
Publication: |
188/218XL ;
419/9 |
International
Class: |
F16D 65/12 20060101
F16D065/12; B22F 7/04 20060101 B22F007/04 |
Claims
1. A method of manufacturing a slotted brake disc rotor or stator
that has a tough, hard, abrasion-resistant ceramic surface on the
portion of the brake disc slot that bears pressure, which method
comprises: i.) providing a carbon-carbon composite brake disc rotor
or stator having slot slots in the interior face of said brake
disc; ii.) applying a paste, comprised of a fine powder of
titanium, zirconium, hafnium, and/or vanadium along with fine
carbon powder suspended in an organic binder, to the areas where
force will be applied to the rotor or stator slot faces; iii.)
placing the disc into a furnace having a nitrogen-containing
atmosphere, and heating the disc to the ignition temperature; and
iv.) cooling the brake disc to ambient temperature.
2. The method of claim 1, wherein the metal powder is titanium
powder.
3. The method of claim 1, wherein the average diameter of the
titanium powder particles ranges from 25 to 250 microns.
4. The method of claim 3, wherein the average diameter of the
titanium powder particles is about 45 microns.
5. The method of claim 1, wherein the carbon powder is powdered
graphite and the average diameter of the graphite particles ranges
from 1 to 10 microns.
6. The method of claim 5, wherein the average diameter of the
graphite particles is about 2 microns.
7. The method of claim 1, wherein the mole ratio of metal powder to
carbon powder ranges from 3:1 to 0.5:1.
8. The method of claim 1, wherein the binder is a phenolic binder,
an epoxy binder, or an alginate binder.
9. The method of claim 1, wherein the paste is applied in a
thickness ranging from 30 microns to 1/4 inch.
10. The method of claim 9, wherein the paste is a layer of titanium
powder and carbon powder about 1/16 inch in thickness.
11. The method of claim 1, wherein the furnace in step iii.) is
provided with an atmosphere containing nitrogen at a pressure
ranging from 0.2 to 20 atmospheres.
12. The method of claim 11, wherein said nitrogen-containing
atmosphere is air.
13. The method of claim 11, wherein said nitrogen-containing
atmosphere is pure nitrogen gas.
14. The method of claim 11, wherein heating step iii.) is conducted
at a temperature of from 400-600.degree. C.
15. A brake disc rotor or stator that has a tough, hard,
abrasion-resistant ceramic surface on the portion of the brake disc
slot that bears pressure, manufactured by the method of claim 1.
Description
FIELD OF THE INVENTION
[0001] This invention relates to carbon-carbon composite brake
discs, and more particularly, to brake disc drive insert slots in
carbon-carbon composite brake discs. The present invention provides
an improved surface within the brake disc drive insert slots.
BACKGROUND OF THE INVENTION
[0002] Carbon-carbon composite brake discs used in the aerospace
industry typically have metal inserts attached to them.
Specifically, the metal inserts are attached to slots in the
interior faces of the brake discs (rotors or stators). Those slots
function to facilitate the transmission of torque to the brake
discs. The metal inserts for stators serve to provide a surface
that will transmit torque from the torque tube of the axle to the
brake disc without crushing the face of the carbon-carbon composite
material. Rotor inserts are used as the media to transmit torque
form the wheel drive key interface to the brake discs. The metal
inserts--typically held in place by rivets, adhesive, etc.--serve
this purpose. However, they are relatively expensive additions to
the brake discs. Labor is expended drilling holes for and attaching
the inserts. Damage sometimes occurs to the carbon-carbon brake
disc during installation or removal of rivets. Also, the inserts
add significant weight to the brake assembly.
[0003] U.S. Pat. No. 5,273,140 describes a brake disc annular drive
insert which comprises a generally cylindrical member with radially
extending flanges at opposite axial ends thereof. The drive insert
includes a generally cylindrical body having an opening at one side
thereof which extends diametrically into the body and terminates at
a point between the center of revolution of the body and an outer
surface of the body. The opening in the body extends to an inner
surface of the body to provide a generally rectangular opening for
receiving a spline of a torque tube. The drive insert is typically
made of steel. The flanges of the drive insert may comprise either
generally annular flanges shaped complementary with the generally
cylindrical body and or may be truncated at a side opposite the
opening in the body.
[0004] US 2007/0175709 describes brake disc drive inserts for use
in carbon-carbon composite brake discs. A rotatable brake disc
annular drive insert includes a cylindrical steel body having one
side of the body truncated to provide an insert opening which
extends axially through the body. The insert opening extends into
the body along a diameter of the body and the insert opening
terminates at a radially extending surface located between the
revolutional center of the body and an outer surface of the body.
End flanges extend radially outwardly from the outer surface of the
body to provide for axial positioning of the drive insert relative
to a brake disc. The insert opening has a lining comprising
carbon-carbon composite material. This low friction carbon-carbon
composite material bed that is positioned between the steel insert
component and the torque tube spline location provides
significantly lower friction and enables significantly greater disc
clamping and brake torque.
[0005] Other prior art of interest includes: US 2007/0235126 A1,
entitled BONDING OF CARBON-CARBON COMPOSITES USING TITANIUM
CARBIDE; US 2007/0235123 A1, entitled APPARATUS AND METHODS FOR
BONDING CARBON-CARBON COMPOSITES THROUGH A REACTANT LAYER;
copending application Ser. No. 11/730,373, entitled BONDING OF
CARBON FIBERS TO METAL INSERTS FOR USE IN COMPOSITES; and US
2007/0193836 A1, entitled METHOD AND BRAKE DISC WITH COMPOSITE
INSERT MEMBER.
SUMMARY OF THE INVENTION
[0006] The present invention eliminates the need for inserts, and
the drilling of rivet holes. Instead, the present invention
toughens the face of the carbon-carbon composite material so that
it will not crush under pressure.
[0007] In accordance with this invention, a brake disc rotor or
stator is manufactured by conventional methods through the final
machining process which provides slots in the interior face of the
brake disc. At that point, this invention applies a paste to the
areas where force is applied to the rotor slot faces or to the
stator slot faces. The paste is comprised of a fine powder of a
carbide-forming metal along with fine carbon powder. The metal and
carbon powders are suspended in an organic binder. The disc is then
placed into a furnace in a nitrogen atmosphere and heated to the
ignition temperature. When the furnace reaches the ignition
temperature, a combustion reaction begins that creates a molten
liquid ceramic material on the slot face. The ceramic created in
this way "cools" very quickly to the temperature of the
carbon-carbon composite. The brake disc is then cooled to ambient
temperature. The resulting brake disc has a tough, hard,
abrasion-resistant ceramic surface on the portion of the brake disc
slot that bears pressure. At this point, the discs are processed
through additional standard processes, such as application of
antioxidant.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The following drawings are illustrative only, and
non-limiting. They illustrate possible ways in which the present
invention, which toughens the face of the carbon-carbon compose
material, may be implemented. However, persons skilled in the art
will readily envision other ways in which the benefits of the
present invention may be obtained.
[0009] FIG. 1A is a top plan view of a known type of aircraft
carbon-carbon composite brake disc stator coupled with a torque
tube via annular drive inserts.
[0010] FIG. 1B is an enlarged view corresponding to the circled
section of FIG. 1A, but modified in accordance with the present
invention.
[0011] FIG. 2A is an isometric view of a known type of aircraft
carbon-carbon composite brake disc rotor.
[0012] FIG. 2B is an enlarged view corresponding to the circled
section of FIG. 2A, but modified in accordance with the present
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0013] This invention provides a method of manufacturing a brake
disc rotor or brake disc stator, wherein the rotor or stator has a
tough, hard, abrasion-resistant ceramic surface on the portion of
the brake disc slot that bears pressure. The method of the
invention includes the following four steps.
[0014] Step (1) contemplates providing a carbon-carbon composite
brake disc rotor or stator having slot slots in the interior face
of said brake disc. These brake disc rotors or stators are
manufactured by conventional methods through the final machining
process which provides slots in the interior faces of the brake
discs.
[0015] Step (2) contemplates applying a paste, comprised of a fine
powder of titanium, zirconium, hafnium, and/or vanadium along with
fine carbon powder suspended in an organic binder, to the areas
where force will be applied to the rotor or stator slot faces. In a
preferred embodiment, the fine powder is titanium powder having an
average particle diameter ranging from 25 to 250 microns. In a more
preferred embodiment, the average particle diameter of the titanium
powder is about 45 microns. In a preferred embodiment, the carbon
powder is powdered graphite and the average diameter of the
graphite particles ranges from 1 to 10 microns. In a more preferred
embodiment, the average particle diameter of the graphite particles
is about 2 microns. In a preferred embodiment, the mole ratio of
metal powder to carbon powder ranges from 3:1 to 0.5:1. In a
preferred embodiment, the organic binder is a phenolic binder, an
epoxy binder, or an alginate binder. In a preferred embodiment, the
paste is applied to the areas where force will be applied to the
rotor or stator slot faces in a thickness ranging from 30 microns
to 1/4 inch. In an especially preferred embodiment, the paste is a
layer of titanium powder and carbon powder about 1/16 inch in
thickness.
[0016] Step (3) contemplates placing the disc into a furnace having
a nitrogen-containing atmosphere, and heating the disc to the
ignition temperature. In a preferred embodiment, the furnace is
provided with an atmosphere containing nitrogen--for instance, air
or pure nitrogen gas--at a pressure ranging from 0.2 to 20
atmospheres. In a preferred embodiment, this heating step is
conducted at a temperature of from 400-600.degree. C.
[0017] Step (4) contemplates cooling the brake disc to ambient
temperature. When the furnace in step (3) reaches the ignition
temperature, a combustion reaction begins that creates a molten
liquid ceramic material on the slot faces in the brake discs. The
ceramic created in this way "cools" very quickly to the temperature
of the carbon-carbon composite. This initial rapid cooling is
followed by cooling the brake disc to ambient temperature,
generally by the application of cooling means such as refrigerants
and/or blowing air.
[0018] This invention also provides a slotted brake disc rotor or
slotted brake disc stator which has a tough, hard,
abrasion-resistant ceramic surface on the portion of the brake disc
slot that bears pressure, said rotor or stator being manufactured
by a method of described above.
[0019] Examples of the metals which may be used in this invention
are titanium, zirconium, hafnium, and/or vanadium. Titanium carbide
provides a ceramic with an especially high specific heat. These
metal powders typically ignite at around 450.degree. C. in a
nitrogen atmosphere. Reaction between nitrogen and metal provides
the low ignition temperature.
[0020] Examples of binders which may be used in this invention
include phenolic binders, epoxy binders, and alginates. However,
any organic binder which can provide a paste of the metal powder
being used can be employed.
[0021] With reference to FIG. 1A, an aircraft carbon-carbon
composite brake disc stator 10 is generally annular in shape and
includes a central generally annular opening 14. A plurality of
slot openings or recesses receiving therein brake disc annular
drive inserts 20 is located about the periphery of opening 14.
Recesses 16 of disc 10 are generally annularly shaped slots
extending radially outwardly from opening 14 of disc 10. Annular
drive inserts 20 couple torque tube 6 with disc 10. The torque tube
is non-rotatably coupled with an axle (not shown) of an
aircraft.
[0022] As illustrated in FIG. 1B, torque tube 6 includes radially
extending short spines 8 which extend within the respective annular
drive slots or openings 21. In accordance with the present
invention, each opening 21 (slot) is lined with an area of
toughened carbon-carbon composite material 19.
[0023] FIG. 2A shows an aircraft carbon-carbon composite brake disc
stator that is generally annular in shape and that includes a
central generally annular opening. A plurality of slot openings or
recesses is located about the outer periphery of the rotor.
[0024] As illustrated in FIG. 2B, in accordance with the present
invention, each opening 21 (slot) is lined with an area of
toughened carbon-carbon composite material 19.
EXAMPLES
Example 1
[0025] A paste is prepared from 1.0 mol of titanium powder and 0.8
mol of carbon powder in a liquid phenolic binder. This paste is
applied in a layer approximately 1/8 inch thick to the faces of
slot slots in a carbon-carbon composite brake disc stator. The
composite disc having the paste-lined slot slots is placed in a
furnace which has a pure nitrogen atmosphere at 1 atmosphere of
pressure. Ignition occurs at about 410.degree. C. The maximum
combustion temperature reached is 2340.degree. C. The resulting
ceramic layer on the faces of the slot slots comprises 0.9 mol TiC
and 0.1 mol TiN. This ceramic layer is a refractory material which
is stable up to about 3000.degree. C. and which has a Rockwell
Hardness, A scale, of about 80 HRA.
Example 2
[0026] A paste is prepared from 1.0 mol of zirconium powder and 1.0
mol of carbon powder in a liquid epoxy binder. This paste is
applied in a layer approximately 3/16 inch thick to the faces of
slot slots in a carbon-carbon composite brake disc rotor. The
composite disc having the paste-lined slot slots is placed in a
furnace which has an air (nitrogen, oxygen, etc.) atmosphere at 0.5
atmospheres of pressure. Ignition occurs at about 600.degree. C.
The maximum combustion temperature reached is 2500.degree. C. The
resulting ceramic layer on the faces of the slot slots comprises
1.0 mol ZrC and 0.2 mol ZrN. This ceramic layer is a refractory
material which is stable up to about 3200.degree. C. and which has
a Rockwell Hardness, A scale, of about 95 HRA.
Example 3
[0027] A paste is prepared from 1.0 mol of vanadium powder and 0.5
mol of carbon powder in a liquid alginate binder. This paste is
applied in a layer approximately 1/16 inch thick to the faces of
slot slots in a carbon-carbon composite brake disc stator. The
composite disc having the paste-lined slot slots is placed in a
furnace which contains pressurized nitrogen gas. Ignition occurs at
about 410.degree. C. The maximum combustion temperature reached is
2400.degree. C. The resulting ceramic layer on the faces of the
slot slots comprises 1.0 mol VC and 0.25 mol VN. This ceramic layer
is a refractory material which is stable up to about 3000.degree.
C. and which has a Rockwell Hardness, A scale, of about 90 HRA.
[0028] While the present invention has been described with respect
to detailed examples of its implementation, the invention is
capable of numerous modifications, rearrangements, and alterations,
and such are intended to be within the spirit and scope of the
foregoing disclosure and the appended claims.
* * * * *