U.S. patent application number 10/043087 was filed with the patent office on 2002-12-05 for highly heat dissipative and abrasion resistant brake disk for bicycles.
Invention is credited to Huang, Chuan-Cheng, Weng, Wen-Pin.
Application Number | 20020179199 10/043087 |
Document ID | / |
Family ID | 21677702 |
Filed Date | 2002-12-05 |
United States Patent
Application |
20020179199 |
Kind Code |
A1 |
Weng, Wen-Pin ; et
al. |
December 5, 2002 |
Highly heat dissipative and abrasion resistant brake disk for
bicycles
Abstract
The present invention provides a highly heat dissipative and
abrasion resistant bicycle brake disk. The brake disk is of a
metal-based composite material, wherein the metal-based composite
material includes a metal-containing material and 5% to 40% by
volume of ceramic particles.
Inventors: |
Weng, Wen-Pin; (Chung-Ho
City, TW) ; Huang, Chuan-Cheng; (Taoyuan City,
TW) |
Correspondence
Address: |
Ross A. Schmitt
c/o LADAS & PARRY
Suite 2100
5670 Wilshire Boulevard
Los Angeles
CA
90036-5679
US
|
Family ID: |
21677702 |
Appl. No.: |
10/043087 |
Filed: |
January 8, 2002 |
Current U.S.
Class: |
148/437 |
Current CPC
Class: |
F16D 69/027 20130101;
F16D 65/00 20130101; F16D 2200/006 20130101; C22C 32/00 20130101;
F16D 2200/003 20130101; F16D 2200/0039 20130101; F16D 65/12
20130101 |
Class at
Publication: |
148/437 |
International
Class: |
C22C 021/08 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 21, 2001 |
TW |
90106578 |
Claims
What is claimed is:
1. A bicycle brake disk of a metal-based composite material,
wherein the metal-based composite material includes a
metal-containing material and 5% to 40% by volume of ceramic
particles.
2. The brake disk as claimed in claim 1, wherein the ceramic
particles are particles of a material selected from the group
consisting of Sic, Al.sub.2O.sub.3, TiB, and B.sub.4C.
3. The brake disk as claimed in claim 2, wherein the ceramic
particles are SiC particles or Al.sub.2O.sub.3 particles.
4. The brake disk as claimed in claim 3, wherein the ceramic
particles are SiC particles.
5. The brake disk as claimed in claim 1, wherein the ceramic
particles have a particle size of 5 to 100 .mu.m.
6. The brake disk as claimed in claim 1, wherein the
metal-containing material has a specific gravity of 1.7 to 4.6
g/cm.sup.3.
7. The brake disk as claimed in claim 1, wherein the
metal-containing material is selected from the group consisting of
aluminium, aluminium alloy, magnesium, magnesium alloy, titanium,
and titanium alloy.
8. The brake disk as claimed in claim 7, wherein the
metal-containing material is aluminum.
9. The brake disk as claimed in claim 7, wherein the
metal-containing material is aluminum alloy.
10. The brake disk as claimed in claim 9, wherein the aluminum
alloy is selected from the group consisting of AlSi, AlSiCu,
AlSiZn, AlSiMg, AlSiCuZn, AlZn, AlZnMg, AlGe, AlGeSi, AlCu, AlMn,
AlMg, AlLi, AlSn, and AlPb.
11. The brake disk as claimed in claim 10, wherein the aluminum
alloy is AlMgSi.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a bicycle brake disk, and
more particularly to a bicycle brake disk made of a metal-based
composite material.
[0003] 2. Description of the Prior Art
[0004] Stainless steel has high abrasion resistance therefore,
bicycle brake disks are generally made of stainless steel. However,
stainless steel disks' adherence is reduced when wet. This causes
slippage in the interface between the brake disk and brake block in
wet or rainy conditions, which in turn results in decreased braking
force In addition, stainless steel has inferior heat dissipation.
Thus, after several successive brakings, the temperature of
stainless steel brake disks becomes relatively high. For mechanical
braking, this high temperature causes the brake disk to become
pliable and deformed, also resulting in inadequate braking force.
For fluid pressure (fluid hydraulic) braking, this high temperature
causes the braking fluid to expand and degrade, which also results
in inadequate braking force
SUMMARY OF THE INVENTION
[0005] Therefore, the object of the present invention is to solve
the above-mentioned problems and to provide a bicycle brake disk
with high heat dissipation and good abrasion resistance.
[0006] To achieve the above object, the highly heat dissipative and
abrasion resistant bicycle brake disk of the present invention is
made of a metal-based composite material, wherein the metal-based
composite material includes a metal-containing material and 5% to
40% by volume of ceramic particles.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 shows a perspective view of a bicycle brake disk of a
metal-based composite material according to the present
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0008] The feature of the present invention is to use a metal-based
composite material to manufacture a bicycle brake disk different
from a conventional brake disk made of stainless steel.
[0009] Refer to FIG. 1, showing a perspective view of a bicycle
brake disk of a metal-based composite material according to the
present invention, The metal-based composite material includes a
metal containing material and 5% to 40%, preferably 5% to 15% by
volume, of ceramic particles. Suitable ceramic particles can be
particles of SiC, Al.sub.2O.sub.3, TiB, or B.sub.4C, preferably SiC
particles or Al.sub.2O.sub.3 particles. Preferably, the ceramic
particles have a particle size of 5 to 100 .mu.m.
[0010] The metal-containing material suitable for use in the
present invention can be aluminium, aluminium alloy, magnesium,
magnesium alloy, titanium, or titanium alloy, preferably aluminum
or aluminum alloy. Representative examples of the aluminum alloy
include AlSi, AlSiCu, AlSiZn, AlSiMg, AlSiCuZn, AlZn, AlZnMg, AlGe,
AlGeSi, AlCu, AlMn, AlMg, AlLi, AlSn, and AlPb, preferably
AlMgSi.
[0011] In the present invention, using the metal-based composite
material to manufacture a bicycle brake disk has the following
advantages: light weight, good heat dissipation, and good abrasion
resistance, explained below.
[0012] The metal-containing material used in the present invention
is preferably a metal or its alloy having a specific gravity of 1.7
to 4.6 g/cm.sup.3. Thus, the brake disk thus manufactured is
lightweight. For example, when the metal-containing material is
aluminum or aluminum alloy, the specific gravity of the composite
of aluminum or aluminum alloy combined with ceramic particles is
approximately 2.8 g/cm.sup.3. The specific gravity of stainless
steel is approximately 7.8 g/cm.sup.3. Thus, the bicycle brake disk
made of the aluminum-based composite material of the present
invention is approximately one third the weight of the conventional
one of stainless steel.
[0013] The thermal conductivity of ceramic particles is about 100
cal/cm.multidot.s.multidot..degree. C., about 1000 times the
thermal conductivity of stainless steel (0.145
cal/cm.multidot.s.multidot..degree- . C.). Therefore, the
metal-based composite material combined with ceramic particles of
the present invention has a much higher thermal conductivity than
stainless steel. Consequently, after several successive brakings,
the bicycle brake disk of the aluminum-based composite material of
the present invention has a temperature that is not too high For
mechanical braking the brake disk better resists becoming pliable
and deformed. For fluid pressure braking, the brake disk better
resists exceeding an acceptable working temperature. After several
successive brakings, the brake disk still provides a good braking
effect.
[0014] The hardness of ceramic particles is Hv 2550, higher than
that of stainless steel (Hv 400) by six times. When the bicycle
brake disk made of the aluminum-based composite material of the
present invention is rubbed against a braking block, the harder
ceramic particles are exposed to the surface, providing the brake
disk of the invention with enhanced abrasion resistance.
[0015] The following examples are intended to illustrate the
process and the advantages of the present invention more fully
without limiting its scope, since numerous modifications and
variations will be apparent to those skilled in the art.
EXAMPLES
[0016] The following tests were taken according to DIN 79100 Part
II 5.6.4 "Breaking performance test".
[0017] The brake disk of the present invention and a conventional
bicycle brake disk were subjected to separate testing. The tested
brake disk of the present invention was made of aluminum-based
composite material (the aluminum alloy AlMgSi, and ceramic
particles SiC). The conventional brake disk was made of stainless
steel. The brake disk was rubbed against a bicycle braking block to
generate a braking force. Testing methods included: (1) brake
performance testing, (2) heat resistance testing, and (3)
mechanical endurance testing.
EXAMPLE 1
[0018] Brake Performance Testing
[0019] (1) Test Content:
[0020] The testing speed (V) in dry conditions was 12.5 km/hr.
[0021] Before any measurements were taken, 10 trials were performed
in order to break in the brake blocks.
[0022] The force applied on the brake lever was not larger than 180
N. The running wheels were not allowed to lock up.
[0023] The average braking force (F) is the average value of the
braking forces determined. The average braking deceleration (a) is
calculated according to the formula: a=F/m.
[0024] The mass (m) is 100 kg for calculation.
[0025] (2) Test Requirement:
[0026] DIN 79100 Part II 5.6.4 requires that the braking
deceleration in dry conditions not be less than 3.4 m/s.sup.2, and
in wet conditions, not be less than 2.2 m/s.sup.2.
[0027] (3) Test Results:
[0028] The test results are shown in Tables 1 and 2.
[0029] For the braking test in dry conditions, the abrasion
resistance of the stainless steel brake disk is provided by its
hardness. As to the aluminum-based composite brake disk, although
the aluminum matrix is soft, once the ceramic particles are exposed
to the surface, these ceramic particles can effectively withstand
abrasion. Thus, the measured abrasion resistance of the brake disc
of either the aluminum-based composite or stainless steel is very
close.
[0030] For braking testing in wet conditions, the stainless brake
disc exhibits slippage in its interface with the braking block
during braking. Thus, the braking force is low. The ceramic
particles in the aluminum-based composite brake disc are much more
easily exposed during the wet braking test. Thus, the
aluminum-based composite brake disk exhibits higher braking force
than a conventional stainless steel brake disk when the same force
is applied to the brake lever.
1 TABLE 1 Force Abrasion applied to Braking condition of the brake
deceleration the brake disc Brake disk type lever (N) (m/s.sup.2)
after test Al-based 80 3.59 no abrasion composite material
Stainless steel 80 3.62 no abrasion
[0031]
2 TABLE 2 Force Abrasion Applied to Braking condition of the brake
deceleration the brake disc Brake disk type lever (N) (m/s.sup.2)
after test Al-based 60 2.59 no abrasion composite material
Stainless steel 60 2.23 no abrasion
EXAMPLE 2
[0032] Heat Resistance Testing
[0033] (1) Test content:
[0034] Braking power =225 W.
[0035] The test period was 2 runs of 15 minutes.
[0036] 10 releases of the brake were allowed during each run, and
the time of each release was not longer than 2 seconds.
[0037] Temperatures were determined during a total determination
period of 30 minutes, and the average temperature was
calculated.
[0038] (2) Test Requirement:
[0039] The temperature of the clamp was not allowed to exceed
100.degree. C. during the heat resistance test.
[0040] (3) Test Results:
[0041] The results are shown in Table 3.
[0042] The thermal conductivity of ceramic particles in the
aluminum-based composite material-made brake disk is higher than
that of stainless steel by 1000 times, allowing them to provide
high heat dissipation. As shown in Table 3, during the heat
resistance test period, the average temperature of the
aluminum-based composite brake disk is lower than that of the
stainless steel brake disk.
3 TABLE 3 Brake disk type Temperature of brake disc Al-based
composite material 58.degree. C. stainless steel 72.degree. C.
EXAMPLE 3
[0043] Mechanical Endurance Testing
[0044] (1) Test Content:
[0045] The testing speed (V) was 12.5 km/hr. Deceleration was 2.2
m/s.sup.2.
[0046] The test braked 3000 times, and each braking lasted for 2.5
seconds.
[0047] Temperatures were regularly measured at an interval of 100
times in the entire testing period. Average temperature was
calculated.
[0048] (2) Test Requirement:
[0049] DIN 79100 Part II 5.6.4 requires that a braking system
should pass 3000 brakings. After the test, the rims must withstand
a force of 300 N applied to the brake lever and 1.5 times the
maximum tire pressure.
[0050] (3) Test Results:
[0051] The 3000 times endurance test can not only detect if the
brake disk can withstand long period of abrasion, but also detect
its working temperature.
[0052] As shown in Table 4, the working temperature of the
aluminum-based composite brake disk is only 68.degree. C., and the
disk suffers no abrasion after testing. This is because the ceramic
particles provide superior abrasion resistance and heat
dissipation. The hardness of the ceramic particles provides high
abrasion resistance. Moreover, the ceramic particles dissipate
frictional heat through radiation, thus providing good heat
dissipation.
[0053] The allowable working temperature for a fluid pressure brake
disk is 130.degree. C. When the temperature exceeds 130.degree. C.,
the fluid in the brake expands and forms bubbles, compromising
braking force. During the entire endurance test, the aluminum-based
composite brake disk of the present invention maintains low working
temperatures. Thus, it is very suitable for use as a brake disk for
a fluid pressure brake, and the braking force can be
maintained.
4 TABLE 4 Abrasion condition of Brake disk the brake disc after
Brake disk type temperature test Al-based 68.degree. C. no abrasion
composite material stainless steel 95.degree. C. no abrasion
[0054] The foregoing description of the preferred embodiments of
the invention has been presented for purposes of illustration and
description. Obvious modifications or variations are possible in
light of the above teaching. The embodiments were chosen and
described to provide the best illustration of the principles of
this invention and its practical application to thereby enable
those skilled in the art to utilize the invention in various
embodiments and with various modifications as are suited to the
particular use contemplated. All such modifications and variations
are within the scope of the present invention as determined by the
appended claims when interpreted in accordance with the breadth to
which they are fairly, legally, and equitably entitled.
* * * * *