U.S. patent application number 09/754691 was filed with the patent office on 2002-07-04 for disc brake rotor.
This patent application is currently assigned to DELPHI AUTOMOTIVE SYSTEMS. Invention is credited to Ballinger, Robert S., Dunlap, Kenneth B., Riehle, Michael A..
Application Number | 20020084156 09/754691 |
Document ID | / |
Family ID | 25035889 |
Filed Date | 2002-07-04 |
United States Patent
Application |
20020084156 |
Kind Code |
A1 |
Ballinger, Robert S. ; et
al. |
July 4, 2002 |
DISC BRAKE ROTOR
Abstract
A disc brake including a pair of friction plates arranged
coaxially in a parallel, spaced-apart relationship and a plurality
of vanes extending between the pair of friction plates, each of
said vanes having a proximal end, a distal end and a mid-portion
extending between the proximal end and the distal end, at least one
of the distal end and the proximal end of at least half the vanes
having a first cross-sectional area, the mid-portion having a
second cross-sectional area, the first cross-sectional area being
substantially greater than the second cross-sectional area. The
vanes can include a T-shaped portion adjacent the distal end. The
vanes can include an hourglass shaped portion. The vanes may taper
from the distal end to the proximal end. The vanes can include a
thicker cross-section adjacent a peripheral portion of the
rotor.
Inventors: |
Ballinger, Robert S.; (West
Chester, OH) ; Dunlap, Kenneth B.; (Springfield,
OH) ; Riehle, Michael A.; (West Chester, OH) |
Correspondence
Address: |
DELPHI TECHNOLOGIES, INC.
Legall Staff, Mail Code: 482-204-450
P.O. BOX 5052
1450 W. Long Lake
Troy
MI
48098
US
|
Assignee: |
DELPHI AUTOMOTIVE SYSTEMS
|
Family ID: |
25035889 |
Appl. No.: |
09/754691 |
Filed: |
January 3, 2001 |
Current U.S.
Class: |
188/218XL ;
188/73.37 |
Current CPC
Class: |
F16D 2065/1328 20130101;
F16D 65/0006 20130101; F16D 65/12 20130101 |
Class at
Publication: |
188/218.0XL ;
188/73.37 |
International
Class: |
F16D 055/36; F16D
065/38 |
Claims
1. A rotor for a disc brake comprising: a pair of friction plates
arranged coaxially in a parallel, spaced-apart relationship; and a
plurality of vanes extending between the pair of friction plates,
each of said vanes having a proximal end, a distal end and a
mid-portion extending between the proximal end and the distal end,
a distal end of a plurality of the plurality of vanes including a
first cross-sectional area, the mid-portion including a second
cross-sectional area, the first cross-sectional area being
substantially greater than the second cross-sectional area.
2. The rotor of claim 1 wherein the first cross-sectional area of
at least half the vanes is substantially greater than the second
cross-sectional area.
3. The rotor of claim 2 wherein the first cross-sectional area of
at least half the vanes is about 50 percent greater than the second
cross-sectional area.
4. The rotor of claim 1 wherein the first cross-sectional area of
all of the vanes is substantially greater than the second
cross-sectional area.
5. The rotor of claim 1 wherein a plurality of the plurality of
vanes includes a T-shaped portion adjacent the distal end of the
vanes.
6. The rotor of claim 5 wherein all of the vanes include a T-shaped
portion adjacent the distal end of the vanes.
7. The rotor of claim 6 wherein half of the vanes include an
inverse T-shaped portion adjacent the proximal end of the
vanes.
8. The rotor of claim 6 wherein the T-shaped portion is at least
50% wider than a width of the mid-portion.
9. The rotor of claim 6 wherein each vane includes an angled
portion located between the T-shaped portion and the
mid-portion.
10. The rotor of claim 6 wherein each of the pair of friction
plates includes a chamfered portion on an inner surface of each
respective friction plate, the chamfered portion being located
adjacent the periphery of the rotor, the vanes being thicker at the
chamfered portion to extend between the pair of plates.
11. The rotor of claim 1 wherein a plurality of the plurality of
vanes include an hourglass shaped portion.
12. The rotor of claim 11 wherein the vanes taper in a width
direction from a distal end along a mid-portion of the vanes at a
location adjacent the friction plates.
13. The rotor of claim 12 wherein a central portion of the vanes
located halfway between the friction plates has a constant width
from the distal end along the mid-portion of the vanes.
14. The rotor of claim 12 wherein each of the vanes include an
increased draft portion having a first thickness located adjacent
the distal end of each vane and a second thickness at a mid-portion
of each vane, the first thickness being greater than a second
thickness.
15. A method of reducing noise in a disc brake rotor comprising:
stiffening a radially outer portion of the brake rotor with an
outer portion of a plurality of vanes; and reducing coupling of
nodal diameter modes in an audible frequency range.
16. The method of claim 15 wherein the outer portion of the
plurality of vanes include a T-shaped portion.
17. The method of claim 15 wherein each vane tapers inwardly from
the outer portion of the plurality of the vanes.
18. A rotor for a disc brake comprising: means for stiffening a
radially outer portion of the brake rotor with an outer portion of
a plurality of vanes; and means for reducing coupling of nodal
diameter modes in an audible frequency range.
19. The rotor of claim 18 wherein the outer portion of the
plurality of vanes includes a T-shaped portion.
20. The rotor of claim 19 wherein the plurality of vanes taper
inwardly from the outer portion of the plurality of the vanes.
Description
TECHNICAL FIELD
[0001] The present invention relates generally to disc brake rotors
as used in a vehicle braking system. More particularly, the
invention relates to a vehicle brake rotor that incorporates a
plurality of vanes designed to reduce noise generated in the brake
system.
BACKGROUND OF THE INVENTION
[0002] Noise generated during a brake application has been
increasing as the size of vehicles has been decreasing. Attempts
have been made to reduce the noise generated using various systems
and methods. One such technique involves the use of sound
adsorption coatings on the pad assembly. While such coatings have
some effectiveness, the addition of the coating adds cost to the
manufacture and at times, undesirable noise occurs when the
thickness of the coating has not been uniform.
[0003] Another technique involves a disc brake pad assembly having
clench tabs extending through rubber-like grommets in openings in a
caliper housing leg so that the grommets are retained in the
openings and the brake pad assembly is retained on the housing leg.
The grommets provide a noise damping action during braking to
reduce noise.
[0004] Individual noise problems have been reduced through the
modification of the ingredients in the composition of materials
that make up a brake pad. In many of these cases, while noise may
have been abated somewhat, the braking effectiveness of the system
has been changed by the modification of the brake pad material.
Still another technique of reducing brake noise involves affixing a
ring damper about a periphery of a brake rotor in a disc brake
system. The ring damper is held in place by a groove formed in the
periphery of the disc and is pre-loaded against the rotor both
radially and transversely.
[0005] The above techniques involve the reduction of noise by
absorbing or masking the noise after it has been created or by
adding costly complexity to the braking system. It would be
advantageous to design the system to reduce the potential for the
creation of noise. It has been suggested that much of brake squeal
or noise is influenced by the excitation of the natural frequencies
of a rotor caused by the rubbing of friction pads on a rotor
surface. There is evidence that a disc brake rotor may have a dozen
or more naturally occurring frequencies. While most of these are in
the axial direction, others are in the torsional direction. In
simulated braking applications only certain of these natural
frequencies create brake noise or squeal. Every natural frequency
of a vibrating system has associated with it a mode shape that
describes the pattern of deformation associated with that natural
frequency. In a continuous structure, the mode shape is generally
accepted or described by defining the pattern of nodes (loci of
points of zero deformation) on the surface of the structure.
Experiments have shown that the mode shape of an annular circular
plate, a shape like that of a brake rotor, consists of nodal
circles and diameters. Thus, a beneficial effect on brake noise
should be attainable if the nodal diameter modes of an installed
disc rotor are maintained at a maximum separation, thereby reducing
or eliminating coupling of the nodal diameter modes in the audible
frequency range.
[0006] A typical structure of a brake rotor includes a central disc
portion that is adapted to be mounted to an axle of a vehicle as in
known in the art, by fasteners. An extending portion typically
connects one of a pair of rotor friction plates or cheeks to the
central disc portion. A plurality of vanes extend from an inner
surface of the first plate to connect a second plate thereto. The
vanes are typically arranged in a radial fashion about the rotor.
The vanes hold the first and second plates in a parallel,
side-by-side relationship. Typically, vanes have an overall regular
elongate, rod, coffin or rectangular shape with a generally
constant width and cross-sectional area. In other words, many
current vanes start out a rectangular cross-section at one end and
remain rectangular throughout the longitudinal distance of the vane
at an opposite end. Similarly, a prior-art plate typically has a
thickness or cross-section remaining substantially constant along
the radial direction.
SUMMARY OF THE INVENTION
[0007] One aspect of the present invention provides a disc brake
including a pair of friction plates arranged coaxially in a
parallel, spaced-apart relationship and a plurality of vanes
extending between the pair of friction plates, each of said vanes
having a proximal end, a distal end and a mid-portion extending
between the proximal end and the distal end, at least one of the
distal end and the proximal end of at least half the vanes having a
first cross-sectional area, the mid-portion having a second
cross-sectional area, the first cross-sectional area being
substantially greater than the second cross-sectional area.
[0008] In other aspects of the invention the cross-sectional area
of the distal end of at least half the vanes can be substantially
greater than the cross-sectional area of the mid-portion. The
cross-sectional area of the distal end of at least half the vanes
can be about 50 percent greater than the cross-sectional area of
the mid-portion. The cross-sectional area of the distal end of all
of the vanes can be substantially greater than the cross-sectional
area of the mid-portion. The cross-sectional area of the distal end
of all of the vanes is substantially greater than the
cross-sectional area of the mid-portion.
[0009] Another aspect of the present invention provides a rotor for
a disc brake having a plurality of first vanes alternated with a
plurality of second vanes, the first and second vanes both having
distal and proximal ends, the distal and proximal ends connected by
an extending mid-portion. A cross-sectional area of the mid-portion
of the first vanes can be substantially greater than a
cross-sectional area of the proximal end. A cross-sectional area of
the distal end of the first vanes can be substantially greater than
the cross-sectional area of the mid-portion. A cross-sectional area
of the mid-portion of the second vanes can be substantially less
than a cross-sectional area of both the distal and proximal
ends.
[0010] Another aspect of the present invention provides a rotor for
a disc brake including a mid-portion having a substantially
constant longitudinal cross-sectional area. The mid-portion of the
vanes can have a narrow portion adjacent the proximal end of the
vanes having a cross-sectional area less than that of a portion
extending outwardly from the narrow portion of the mid-portion of
the vanes.
[0011] Another aspect of the present invention provides a rotor for
a disc brake including a pair of friction plates arranged coaxially
in a parallel, spaced-apart relationship and a plurality of vanes
extending between the pair of friction plates, each of the vanes
having a proximal end, a distal end and a mid-portion extending
between the proximal end and the distal end, at least half of the
vanes including a T-shaped portion adjacent the distal end of the
vanes.
[0012] Other aspects of the present invention provide a rotor
wherein all of the vanes include a T-shaped portion adjacent the
distal end of the vanes. Half of the vanes of the rotor including a
T-shaped portion can include an additional inverse T-shaped portion
adjacent the proximal end of the vanes. The T-shaped portion can be
at least 50% wider than a width of the mid-portion. Each vane can
include an angled portion located between the T-shaped portion and
the mid-portion. In an alternate aspect of the present invention
all of the vanes can include a T-shaped portion adjacent each
respective distal end.
[0013] Another aspect of the present invention provides a rotor
wherein each of the pair of friction plates includes a chamfer on
an inner surface of each friction plate, the chamfer being located
adjacent the periphery of the rotor, the vanes being thicker at the
chamfer to extend between the pair of plates.
[0014] Another aspect of the present invention provides a rotor for
a disc brake including a pair of friction plates arranged coaxially
in a parallel, spaced-apart relationship and a plurality of vanes
extending between the pair of friction plates, each of said vanes
having a proximal end, a distal end and a mid-portion extending
between the proximal end and the distal end, at least half of the
vanes including an hourglass shaped portion.
[0015] Other aspects of the invention provide a rotor where the
hourglass shaped portion extends along an entire length of the
vanes. The hourglass shaped portion can extend from the mid-portion
to the distal end of the vanes. Half of the vanes can include an
hourglass shaped portion extending along an entire length of the
vanes and the other half of the vanes include an hourglass shaped
portion extending from a mid-portion to a distal end of the vanes.
A width of the vanes can taper from a distal end along a
mid-portion of the vanes at a location adjacent the friction
plates. A central portion of the vanes located halfway between the
friction plates can have a constant width from the distal end along
the mid-portion of the vanes. Each of the vanes can include an
increased draft portion having a first thickness located adjacent
the distal end of each vane and a second thickness at a mid-portion
of each vane, the first thickness being greater than a second
thickness.
[0016] An aspect of the present invention includes a method of
reducing noise in a disc brake rotor including stiffening a
radially outer portion of the brake rotor with an outer portion of
a plurality of vanes and reducing coupling of nodal diameter modes
in an audible frequency range. The outer portion of the plurality
of vanes can include a T-shaped portion.
[0017] Another aspect of the invention includes a rotor for a disc
brake including means for stiffening a radially outer portion of
the brake rotor with an outer portion of a plurality of vanes and
means for reducing coupling of nodal diameter modes in an audible
frequency range. The outer portion of the brake rotor can include a
T-shaped portion.
[0018] The foregoing and other features and advantages of the
invention will become further apparent from the following detailed
description of the presently preferred embodiments, read in
conjunction with the accompanying drawings. The detailed
description and drawings are merely illustrative of the invention
rather than limiting, the scope of the invention being defined by
the appended claims and equivalents thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 illustrates an embodiment of a brake rotor of the
present invention having T-shaped vanes.
[0020] FIG. 2 illustrates an alternating arrangement of the vanes
in the brake rotor of FIG. 1.
[0021] FIG. 3 illustrates a second embodiment of a brake rotor of
the present invention having hourglass and I-shaped vanes with an
expanding thickness along a longitudinal direction.
[0022] FIG. 4 illustrates a third embodiment of a brake rotor of
the present invention having variable draft vanes.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0023] Referring to FIGS. 1 and 2, one embodiment of a brake rotor
is generally shown at numeral 110. The brake rotor 110 includes a
central attachment portion 112. An extending portion 114 is
attached adjacent to the periphery 116 of the central attachment
portion 114. A first friction plate 118 (one of a pair of parallel
friction plates) is depicted attached to the central attachment
portion 112 by the extending portion 114. A second friction plate
(not shown), which would be oriented in a parallel, spaced apart
relationship to the first plate 118 is omitted to show the
structure therebetween. A plurality of vanes 120, 122 is provided
that extend between the plates and are arranged in a radial
fashion. The vanes 120, 122 are radial members, each having a
proximal end 124, 126 adjacent the extending portion 114 and a
middle span or mid-portion 128, 130 that extends longitudinally in
a radial direction to a distal end 132, 134. The distal end 132,
134 is located adjacent the outer periphery 136 of the friction
plates.
[0024] In one embodiment, a first and a second set of vanes 120,
122 are provided between the plates in an alternating arrangement.
In other words, a first vane 120 is followed by an adjacent second
vane 122, which is followed by a first vane 120 and so on, around
the rotor 110. Each of the first set of vanes 120 has a T-shape
configuration. The top of the T portion 138 is located in the
distal end 132 of the vane 120. The middle span 128 of the vane 120
is essentially a longitudinally extending rectangular portion. The
vane 120 includes an angled portion 140 between the middle span 128
and the T-shaped portion 138. The T portion 138 of the vane 120 can
have a width about 50% greater than that of the middle span 128 of
the first vane 120. The T portion 138 of each vane 120 can have a
width about twice that of the middle span 128 of the first vane
120. Also, the cross-sectional area of portion 138 can be made from
about 50% greater to about twice that of the middle span 128 of the
first vanes 120. In this embodiment, the inner peripheral edges of
the plates can be chamfered. As a result of the chamfered portion
142, the thickness of the vane 120, i.e., the distance between the
friction plates, at the distal end 132 is greater than at the
mid-portion 128 and proximal end 124 of the vane 120.
[0025] Arranged in an alternate fashion with the first vanes 120 is
a set of second vanes 122. The second vanes 122 include the
T-shaped configuration of the distal portion of the first vanes
120. However, the second vanes 122 each can include an I-shaped
configuration. The proximal end 216 of each of the vanes 122 has a
wide portion 144 similar to the wide portion of the distal end 134.
It is believed that the widened portion or T-shaped 120 and
I-shaped vanes 122 adds mass and stiffness to the outer periphery
(and inner periphery in the case of the I-shaped vanes) of the
rotor 110 and thus, compared to a prior art rotor, has a
beneficially modified pattern of nodal resonance modes.
[0026] Referring to FIG. 3, another embodiment of the brake rotor
is generally shown at 210. In this illustration it can be seen that
the vanes 220, 222 have an hourglass shape. The hourglass shape can
be seen in the distal exposed end section shown at 221. At a
mid-point 260 of the thickness D.sub.T of each vane 220, 222, i.e.,
halfway between the plates, the longitudinal cross-section (not
shown) can be rectangular or a constant thickness from a proximal
portion 224, 226 to a distal portion 232, 234. However, the vanes
220, 222 each can taper inwardly toward their proximal ends 224,
226 where the vanes contact the inner surface 250 of the friction
plate 218. Thus, the vanes are wider (D.sub.W) adjacent the plate
surface at the distal ends 232, 234 of the vanes 220, 222. The
shape of the area defined between the vanes on the rotor inner
plate surface 250 can be rectangular as a result of the taper of
the vanes 220, 222.
[0027] The second set of vanes 222 can be alternated between the
first set of vanes 220. The second set of vanes 222 can be similar
to the first vanes 220 with the addition of an inverted T-shaped
portion adjacent the proximal end 226 of vane 222. It is believed
that the hourglass-shaped cross-section of the vanes 220, 222 and
the inverted T-shaped portion 244 adds mass and stiffness to the
outer periphery (and inner periphery in the case of the inverted
T-shaped vanes) of the rotor 210 and thus, compared to a prior art
rotor, has a beneficially modified pattern of nodal resonance
modes.
[0028] FIG. 4 illustrates another embodiment of the rotor 310 of
the present invention. The first and second vanes 320, 322 of the
embodiment shown in FIG. 4 are similar to those shown in FIG. 3
with the exception of the use of variable draft vanes 320, 322. The
inside surfaces 350, 351 of the first and second friction plates or
cheeks 318, 319 in FIG. 4 are tapered toward the outer periphery of
each plate. In this manner, the rotor 310 shown can beneficially
minimizes a temperature gradient from the rotor inner thickness or
diameter, generally shown at 370, to the rotor outer diameter,
generally shown at 371. Each vane extends a greater distance
D.sub.T between the plates 318, 319 at the outer periphery of the
rotor 371. Thus, the distal ends 332, 334 of the vanes 320, 322
each have a greater thickness D.sub.T than at a proximal 324, 326
or middle portion of each of the vane.
[0029] Each of a first set of hourglass vanes 320 has a
longitudinal, generally rectangular shape with a gradual taper
toward the proximal end 324 adjacent the friction plates 318, 319.
The first vanes 320 are alternated with second vanes 322. Each
second vane 322 has a longitudinally oriented inverted T-shape.
Each of the vanes 322 has an hourglass shape in a cross-section of
the middle 328 (of vane 320) and distal portions 332, 334. Each of
the second vanes 322, at a proximal end 334, has an angled portion
that widens to a T-shaped portion of the vane like that shown in
FIG. 3.
[0030] During use, the rotor generates a large number of nodal
diameter modes. Each of the nodal diameter modes generates a
different pattern of resonant rotor vibration. When the nodal
diameter modes converge or couple, noise is often produced. Also,
the location of the highest strain energy for the nodal diameter
nodes is at the extreme outside diameter on the rotor. In
operation, the present invention provides vanes that, as a result
of the vane geometry, add stiffness to the rotor at the extreme
outside diameter of the rotor. The increased stiffness of the outer
diameter of the rotor tends to increase separation (spacing) of the
nodal diameter nodes. This can reduce coupling of the nodal
diameter modes. The increased separation and reduction of the
coupling of the nodal diameter nodes reduces the likelihood of the
rotor producing noise in the audible frequency range during
use.
[0031] While the embodiments of the invention disclosed herein are
presently considered to be preferred, various changes and
modifications can be made without departing from the spirit and
scope of the invention. The scope of the invention is indicated in
the appended claims, and all changes that come within the meaning
and range of equivalents are intended to be embraced therein.
* * * * *