U.S. patent application number 10/353897 was filed with the patent office on 2004-07-29 for pure iron fiber based friction material product.
Invention is credited to Hayashi, Hajime, Shao, Xinming.
Application Number | 20040146702 10/353897 |
Document ID | / |
Family ID | 32655535 |
Filed Date | 2004-07-29 |
United States Patent
Application |
20040146702 |
Kind Code |
A1 |
Shao, Xinming ; et
al. |
July 29, 2004 |
Pure iron fiber based friction material product
Abstract
A friction material having a reinforcement material that
includes mineral fibers, metal fibers, aramid fibers, cellulose
fibers and combinations thereof but does not include carbon steel.
The friction material has a relatively uniform coefficient of
friction and causes relatively less wear of braking components.
Inventors: |
Shao, Xinming; (Rochester
Hills, MI) ; Hayashi, Hajime; (Novi, MI) |
Correspondence
Address: |
HARNESS, DICKEY & PIERCE, P.L.C.
P.O. BOX 828
BLOOMFIELD HILLS
MI
48303
US
|
Family ID: |
32655535 |
Appl. No.: |
10/353897 |
Filed: |
January 29, 2003 |
Current U.S.
Class: |
428/292.1 |
Current CPC
Class: |
F16D 2200/0065 20130101;
F16D 69/026 20130101; Y10T 428/249924 20150401 |
Class at
Publication: |
428/292.1 |
International
Class: |
D04H 001/00 |
Claims
What is claimed is:
1. A braking element comprising a friction material, the friction
material being entirely devoid of carbon steel and including: a
reinforcement material selected from a group consisting essentially
of mineral fibers, non-carbon steel metal fibers, aramid fibers,
cellulose fibers, and combinations thereof.
2. The braking element of claim 1, wherein the metal fibers are
iron fibers.
3. The braking element of claim 2, wherein the iron fibers are
annealed.
4. The braking element of claim 2, wherein a length of the iron
fibers is in a range of about 0.5 millimeters to about 6
millimeters.
5. The braking element of claim 4, wherein the length of the iron
fibers is in a range of about 2.2 millimeters to about 3.2
millimeters.
6. The braking element of claim 2, wherein a width of the iron
fibers is in a range of about 25 micrometers to about 200
micrometers.
7. The braking element of claim 6, wherein the width of the iron
fibers is in a range of about 60 micrometers to about 90
micrometers.
8. The braking element of claim 2, wherein a length-to-width ratio
of the iron fibers ranges between about 2.5 to 1 to about 240 to
1.
9. The braking element of claim 2, wherein an amount of the iron
fibers in the friction material ranges between about 0.5 v % to
about 40 v %.
10. The braking element of claim 9, wherein the amount of the iron
fibers in the friction material ranges between about 2 v % to about
28 v %.
11. The braking element of claim 1, wherein the non-carbon steel
metal fibers are selected from a group consisting of brass fibers,
copper fibers, bronze fibers, iron fibers and combinations
thereof.
12. A friction material being entirely devoid of carbon steel and
including: a reinforcement material selected from a group
consisting essentially of mineral fibers, non-carbon steel metal
fibers, aramid fibers, cellulose fibers, and combinations
thereof.
13. The friction material of claim 12, wherein the metal fibers are
iron fibers.
14. The friction material of claim 13, wherein the iron fibers are
annealed.
15. The friction material of claim 13, wherein a length of the iron
fibers is in a range of about 0.5 millimeters to about 6
millimeters.
16. The friction material of claim 15, wherein the length of the
iron fibers is in a range of about 2.2 millimeters to about 3.2
millimeters.
17. The friction material of claim 13, wherein a width of the iron
fibers is in a range of about 25 micrometers to about 200
micrometers.
18. The friction material of claim 17, wherein the width of the
iron fibers is preferably in a range of about 60 micrometers to
about 90 micrometers.
19. The friction material of claim 13, wherein a length-to-width
ratio of the iron fibers ranges between about 2.5 to 1 to about 240
to 1.
20. The friction material of claim 13, wherein an amount of the
iron fibers in the friction material ranges between about 0.5 v %
to about 40 v %.
21. The friction material of claim 20, wherein the amount of the
iron fibers in the friction material ranges between about 2 v % to
about 28 v %.
22. The friction material of claim 12, wherein the non-carbon steel
metal fibers are selected from a group consisting of brass fibers,
copper fibers, bronze fibers, iron fibers, and combinations
thereof.
23. A clutch comprising a friction material, the friction material
being entirely devoid of carbon steel and including: a
reinforcement material selected from a group consisting essentially
of mineral fibers, non-carbon steel metal fibers, aramid fibers,
cellulose fibers, and combinations thereof.
24. The clutch of claim 23, wherein the metal fibers are annealed
iron fibers.
25. The clutch of claim 24, wherein a length-to-width ratio of the
annealed iron fibers ranges between about 2.5 to 1 to about 240 to
1.
26. The clutch of claim 24, wherein an amount of the annealed iron
fibers in the friction material ranges between about 0.5 v % to
about 40 v %.
27. The clutch of claim 24, wherein an amount of the annealed iron
fibers in the friction material ranges between about 2 v % to about
28 v %.
28. A braking element comprising a friction material, the friction
material comprising iron fibers and not carbon steel.
29. The braking element of claim 28, wherein an amount of the iron
fibers in the friction material ranges between about 0.5 v % to
about 40 v %.
30. The braking element of claim 29, wherein the amount of the iron
fibers in the friction material ranges between about 2 v % to about
28 v %.
31. The braking element of claim 29, wherein a length-to-width
ratio of the iron fibers ranges between about 2.5 to 1 to about 240
to 1.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] Other features of the present invention are discussed and
claimed in commonly assigned copending U.S. application Ser. No.
______ entitled Brake Friction Material including Titanium Dioxide
Particles, filed on ______.
FIELD OF THE INVENTION
[0002] The present invention relates to a friction material, and
more particularly relates to a reinforcement in the friction
material for particular use in an industrial machine, a railway
vehicle, a baggage car, a passenger car, a freight truck, or the
like wherein a brake pad, a brake lining, a clutch facing, or the
like, is used in the above-mentioned applications
BACKGROUND OF THE INVENTION
[0003] Automotive brake systems must satisfy a certain set of
consumer expectations, such as comfort, durability, and reasonable
cost. These expectations are translated into a set of specific
requirements for the brake system such as a high and stable
friction coefficient, vibration and noise characteristics within a
predetermined limit, and low wear rates for the friction material
and rotor mating surfaces. All of the aforesaid requirements have
to be achieved simultaneously at a reasonable cost. Particularly,
the performance has to be stable under varying application
conditions, over extremes in temperature, humidity, speed, and
deceleration rate for occasional or many consecutive stops.
[0004] Friction materials serve in a variety of ways to control the
acceleration and deceleration of vehicles and machines. The
friction materials may be resin- or rubber-bound composites based
on asbestos, metallic fibers, or a combination of other fibers. The
friction material is generally composed of binders, reinforcements,
and fillers.
[0005] Brake linings and clutch facings consist of friction
materials, which are employed to convert the kinetic energy of the
moving vehicle or machine part into heat to thereby remove the
kinetic energy and halt the movement of the vehicle or machine
part. Typically, the friction material absorbs the heat and
gradually dissipates it into the atmosphere. The friction material
is considered to be the expendable portion of the brake couple
which, over a long period of use, is converted to wear debris and
gases.
[0006] Reinforcement materials are frequently employed in friction
materials for enhancing a predetermined characteristic such as
increasing the strength of the friction material, providing varying
degrees of wear resistance, heat dissipation, temperature
stabilization, and/or high and low temperature friction
performance.
[0007] Reinforcement materials are also used to provide an abrasive
attribute to the friction material. The magnitude of abrasiveness
of the filler dictates many performance and wear characteristics of
the braking system. To that end, extreme abrasiveness may lead to
excellent performance but contribute to excessive wear of braking
components. Insufficient abrasiveness may protect the braking
components but provide relatively poor braking characteristics.
SUMMARY OF THE INVENTION
[0008] In one preferred form, the present invention provides a
braking element comprising a friction material, which is comprised
of a binder, a filler, and a reinforcement material. The
reinforcement material essentially consists of mineral fibers,
metal fibers, aramid fibers, cellulose fibers, and combinations
thereof. The metal fibers are an annealed iron fiber with a length
in range of about 0.5 to about 6 millimeters and a width in a range
of about 25 micrometers to about 200 micrometers. The iron fiber
content in the friction material is in a range between about 0.5 v
% to about 40 v %.
[0009] Further areas of applicability of the present invention will
become apparent from the drawings and detailed description provided
hereinafter. It should be understood that the detailed description
and specific examples, while indicating the preferred embodiment of
the invention, are intended for purposes of illustration and
example only and are not intended to limit the scope of the
invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The present invention will become more fully understood from
the detailed description and the accompanying drawings,
wherein:
[0011] FIG. 1 is a cross-sectional view of a disc brake system.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0012] In FIG. 1, a preferred embodiment of the present invention
is shown with reference to a simplified and exemplary vehicle disc
brake system 10. The disc brake system 10 includes a rotor 12, a
caliper 14, and a hub 16. The disc brake system 10 also includes a
pair of outboard and inboard brake elements 18a and 18b,
respectively, referred to hereinafter as brake elements 18. The
brake elements 18 are mounted to the caliper 14 using conventional
methods well known to one of ordinary skill in the art. One of
ordinary skill in the art will readily appreciate the brake system
10 is shown in an simplified fashion; a more detailed explanation
of an exemplary disc brake system is shown in commonly assigned
U.S. Pat. No. 4,351,421, which is hereby incorporated by reference
in its entirety as if fully set forth herein.
[0013] The brake elements 18 include a structural backing 20 and a
friction material 22. The friction material 22 is mounted to the
structural backing 20 in a conventional way, well-known to one of
ordinary skill in the art. An example of one such mounting method
is disclosed in commonly assigned U.S. Pat. No. 5,073,099, which is
hereby incorporated by reference in its entirety as if fully set
forth herein.
[0014] The brake elements 18 squeeze against rotor 12 to slow the
rotation of the rotor 12 to thereby slow the vehicle (not shown) to
a desired speed. As noted above, friction is produced when the
brake elements 18 come into contact with the rotor 12; this in
turn, causes the brake elements 18 to heat up and ultimately
wear.
[0015] The friction material 22 is comprised of a binder, a filler,
and a reinforcement, which may be combined in a slurry form, for
example, and pressed or molded into a desired shape. The
reinforcement is comprised of iron fibers but neither the
reinforcement, the binder, nor the filler includes low-carbon
steel. The formulation of the friction material in this manner
provides many advantages in performance and durability; the
benefits of which will be discussed further. Additionally, iron
fibers without low-carbon steel provide a low cost and advantageous
composition of the friction material. As those of ordinary skill in
the art will appreciate, low-carbon steel is used in a friction
material for purposes that include reinforcement. Accordingly, it
will be understood that no carbon steel will be included in the
friction material when it is stated that the reinforcement lacks a
low-carbon steel component.
[0016] In the preferred embodiment of the present invention, the
reinforcement of the friction material comprises an annealed iron
fiber but is devoid of low-carbon steel. The iron fibers are
commercially available from many vendors. One such exemplary
supplier is Sunny Metal Inc. 01, Jinxin Road, Nancun-Yuangang,
Panyu, Guangzhou, China, 511442, under the product name Annealed
Vibration Cutting Iron Fiber. One of ordinary skill in art will
readily appreciate that iron fibers of the requisite type and
dimension can be acquired from many vendors.
[0017] In the preferred embodiment of the present invention, the
length of the iron fibers is in a range of about 0.5 millimeter to
about 6 millimeters, with a preferred range of about 2.2
millimeters to about 3.2 millimeters providing optimal performance.
The width of the irons fibers is in a range of about 25 micrometers
to about 200 micrometers, with a preferred range of about 60
micrometers to about 90 micrometers providing optimal performance.
To maintain desired performance characteristics of the friction
material, the length-to-width ratio of iron fibers ranges between
about 2.5 to 1 to about 240 to 1. One skilled in the art will
readily appreciate that deviation from the exact sizes of the iron
fibers will not render the invention inoperable but may only reduce
performance.
[0018] Experimental results have shown that use of iron fibers
without any low-carbon steel in the remainder of the friction
material produces less disc thickness variation and overall wear of
the braking components than friction materials containing
low-carbon steel. Disc thickness variation or DTV refers to
non-uniform thickness of the disc rotor. Disc thickness variation
can be caused by many different things, one of which includes
intermittent rubbing between the friction material and the rotor
when the caliper is not engaged (brake pedal is not pressed)
because the braking element has not fully disengaged the rotor. A
rotor with disc thickness variation will transmit a pulsing
sensation as the braking element intermittently makes contact with
the rotor. Tests measuring disc thickness variation show that
friction materials with iron fibers that are devoid of low-carbon
steel as compared to friction materials with low-carbon steel show
a reduction of disc thickness variation of approximately 60%.
[0019] The exclusion of low-carbon steel fibers in the friction
material allows the characteristics of the iron fiber to
predominate the reinforcement component of the friction material.
To that end, the iron fibers are a softer metallic fiber when
compared to low-carbon steel fibers. Using the softer iron fibers
produces less disc thickness variation as mentioned above. Further,
it produces less judder and other forms of vibration that for
example wear suspension components.
[0020] The iron fibers are softer and produce less brake component
wear but the exclusion of low-carbon steel also produces a friction
coefficient of less magnitude, generally in the range of about 3.5
to about 4. Notwithstanding the reduction in magnitude of the
friction coefficient, the breaking elements can easily produce
enough frictional force to stop a vehicle. The slight change in the
magnitude of the friction coefficient of the friction material
relative to friction materials containing low-carbon steel may
provide minor changes in the duty cycle of the friction material
depending on the application. Accordingly, graphite lubricants,
coarser graphite, or other conventional components of the friction
material may be adjusted as necessary to maintain the robustness
and overall durability of the friction material.
[0021] In the preferred embodiment, annealed iron fibers are mixed
into the friction material as a percentage of total volume of the
friction material, such that a range is about five-tenths of one
percent by volume (0.5 v %) up to about forty percent by volume (40
v %). A preferred range is about two percent by volume (2 v %) up
to about twenty-eight percent by volume (28 v %), with the
preferred range providing optimal performance characteristics. One
skilled in the art will readily appreciate that adherence to the
exact percentage of total volume per component is not required to
maintain operability of the invention, but the deviation from the
exact percentages may reduce performance of the friction
material.
[0022] Table 1 shows the preferred ranges of a first exemplary
composition of the friction material where the values found in the
column labeled "Preferred Example Ranges" represents preferred
ranges of the components within the friction material.
1 TABLE 1 Preferred Example Ranges Exemplary Components of
(percentage of the Friction Material total volume) Phenolic Resin
about 5 to 23 Mineral Fiber about 0 to 12 Iron Fiber about 2 to 28
Brass Fiber about 0 to 10 Copper Fiber about 0 to 10 Bronze Fiber
about 0 to 10 Cellulose Fiber about 0 to 8 Aramid Fiber about 0 to
5 Barium Sulfate about 3 to 15 Coke/Graphite about 1 to 30 Metal
Sulfides about 0 to 15 Metal Powders about 1 to 35 Reground rubber
tire tread dust about 1 to 9 Cashew Nut Shell Friction Dust about 2
to 20 Titanium Dioxide Particles about 2 to 20 Other metals of
metal oxides about 0 to 10
[0023] Table 2 shows the preferred values of a second exemplary
composition of the friction material where the values found in the
column labeled "Preferred Example Values" are preferred values for
the friction material. One skilled and the art will readily
appreciate that the values outlined below in Table 1 and Table 2
are exemplary ranges and values and, as such, do not limit the
scope of the present invention.
2 TABLE 2 Preferred Example Values Components of the (percentage of
Friction Material total volume) Phenolic Resin about 14 Iron Fiber
about 25 Aramid Fiber about 2 Barium Sulfate about 12 Synthetic
Graphite about 30 Reground rubber tire tread dust about 3 Cashew
Nut Shell Friction Dust about 4 Titanium Dioxide Particles about 8
Zinc Powder about 2
[0024] One of ordinary skill in art will readily appreciate that
many vendors supply multiple commercially available mineral fibers
suitable for use in the friction material. In the preferred
embodiment of the present invention, one such exemplary mineral
fiber is Lapinus.RTM. Fiber, which is commercially available from
Lapinus Fibres B.V., 6040 KD Roermond, The Netherlands, under the
trade name Roxul.RTM. 1000. Roxul.RTM. 1000, for example, is a gray
and/or green fibrous mineral wool batting or board.
[0025] One of ordinary skill in art will readily appreciate that
many vendors supply multiple commercially available ceramic fibers
suitable for use in the friction material. In the preferred
embodiment of the present invention, one such exemplary ceramic
fiber is Superwool.RTM. Fiber, which is commercially available from
Thermal Ceramics, P.O. Box 923, Dept. 167, Augusta, Ga. 30903.
Superwool.RTM. Fiber, for example, is an alkaline earth silicate
wool batting or board.
[0026] One of ordinary skill in art will readily appreciate that
many vendors supply multiple commercially available cellulose
fibers suitable for use in the friction material. In the preferred
embodiment of the present invention, one such exemplary cellulose
fiber is Interfiber.RTM., which is commercially available from
Vanco Manufacturing, Inc., 1615 Vanderbilt Road, Portage, Mich.
49002. Interfiber.RTM., for example, is a polyoxypropylene
powder.
[0027] One of ordinary skill in art will readily appreciate that
many vendors supply multiple commercially available metal sulfides
suitable for use in the friction material. In the preferred
embodiment of the present invention, possible exemplary metal
sulfides are antimony tri-sulfide, copper sulfide, stannic sulfide,
and stannous sulfide all of which are commercially available.
[0028] One of ordinary skill in art will readily appreciate that
many vendors supply multiple commercially available forms of
graphite suitable for use in the friction material. In the
preferred embodiment of the present invention, one such exemplary
source of suitable commercially available graphite is from Asbury
Carbons, Inc., 405 Old Main Street, Asbury, N.J., 08802.
[0029] One of ordinary skill in art will readily appreciate that
many vendors supply multiple commercially available aramid fibers
suitable for use in the friction material. In the preferred
embodiment of the present invention, one such exemplary mineral
fiber is Kevlar.RTM. Fiber, which is commercially available from
DuPont, 5401 Jefferson Davis Hwy, Richmond, Va. 23234 among
others.
[0030] The titanium dioxide particles mentioned above are discussed
in greater detail in commonly assigned copending U.S. application
Ser. No. ______ entitled Brake Friction Material including Titanium
Dioxide Particles, filed on ______, which is hereby incorporated by
reference in its entirety as if fully set forth herein.
[0031] Another component of the friction material is the filler.
Exemplary fillers include anti-oxidants, asbestos, barium sulfate,
calcium carbonate, cashew nut oil, cotton, fiber of mixed oxides,
lime, potassium titanate, diene rubber, nitrile rubber, scrap
rubber, sea coal, and zinc oxide among others. One skilled in the
art will readily appreciate the wide ranging the availability of
other filler materials. A more detailed list of possible and
exemplary fillers is disclosed in Compositions, Fucntions, and
Testing of Friction Brake Materials and their Additives by Peter J.
Blau (prepared by the Oak Ridge National Laboratory, Document
Number ORNL/TM-2001.64), which is incorporated by reference in its
entirety as if fully set forth herein.
[0032] In the preferred embodiment, the use of iron fibers while
excluding any low-carbon steel fibers in the reinforcement of the
friction material in no way alters the applicability of the
friction material. While the percent of total volume or size of
other components in the friction material may need to be adjusted
to compensate for the specific needs of certain applications, the
iron fibers provide benefits across many friction material
applications. One skilled in art will readily appreciate that
components in a friction material can be adjusted to tailor the
friction material to the wide range of applications without
deviating from the scope of the present invention. Further, the
ability to dissipate heat is not hindered with use of iron fibers
without low-carbon steel fibers, as reinforcement composition
provides equal or better heat dissipation characteristics when
compared to other reinforcement compositions.
[0033] In the preferred embodiment of the present invention, the
binder is a phenolic resin. The friction material components are
subjected to a surface treatment with a phenolic resin. The
substances subjected to such a surface treatment have an advantage
that they can be easily mixed with other materials when a friction
material is manufactured. The mixture by volume of the phenolic
resin is preferably in a range of nine percent by volume (9 v %) to
twenty five percent by volume (25 v %).
[0034] In alternative embodiment, a silane coupling agent can be
used in lieu of the phenolic resin. Further detail as to use and
substitution of the phenolic resin, the silane coupling agent or
other binders, is more fully discussed in commonly assigned pending
U.S. patent application Ser. No. 09/735,625, which is hereby
incorporated by reference in its entirety as if fully set forth
herein.
[0035] The foregoing description of the invention is merely
exemplary in nature and, thus, variations that do not depart from
the gist of the invention are intended to be within the scope of
the invention. Such variations are not to be regarded as a
departure from the spirit and scope of the invention.
* * * * *