U.S. patent application number 12/947109 was filed with the patent office on 2011-03-10 for pneumatic tire.
This patent application is currently assigned to THE GOODYEAR TIRE & RUBBER CMPANY. Invention is credited to Peter Johann Cornelius Maus.
Application Number | 20110056606 12/947109 |
Document ID | / |
Family ID | 40251719 |
Filed Date | 2011-03-10 |
United States Patent
Application |
20110056606 |
Kind Code |
A1 |
Maus; Peter Johann
Cornelius |
March 10, 2011 |
PNEUMATIC TIRE
Abstract
A pneumatic radial tire has a pair of opposing bead portions 14,
each bead portion 14 has a bead core 23 and a bead apex 24; at
least one carcass reinforcing ply 12 having radially oriented steel
cords 22, the at least one carcass reinforcing ply 12 has a main
portion 18 and two turnups 20, one turnup 20 extending from each
end of the main portion 18 and having a terminal end 21, the
carcass reinforcing ply main portion 18 extends between the
opposing bead cores 23 and turnups 20 are located axially outward
of the bead core 23 and a portion of the bead apex 24; and two
pairs of steel cord reinforced chippers, one pair adjacent each
turnup, each pair having one inner chipper 40 being adjacent and on
an axially inner side of the turnup 20 and one outer chipper 30
being adjacent on an axially outer side of the turnup 20, the inner
and outer chippers 40, 30 being adjacent the turnup 20 each have a
terminal end 41, 31 extending radially outward of the terminal end
21 of the turnup 20.
Inventors: |
Maus; Peter Johann Cornelius;
(Bullingen, BE) |
Assignee: |
THE GOODYEAR TIRE & RUBBER
CMPANY
Akron
OH
|
Family ID: |
40251719 |
Appl. No.: |
12/947109 |
Filed: |
November 16, 2010 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
11936241 |
Nov 7, 2007 |
|
|
|
12947109 |
|
|
|
|
Current U.S.
Class: |
152/526 ;
152/552 |
Current CPC
Class: |
Y10T 152/10828 20150115;
Y10T 152/10819 20150115; B60C 15/06 20130101; Y10T 152/10837
20150115; Y10T 152/10765 20150115; B60C 2015/009 20130101 |
Class at
Publication: |
152/526 ;
152/552 |
International
Class: |
B60C 9/04 20060101
B60C009/04; B60C 9/18 20060101 B60C009/18 |
Claims
1. A pneumatic radial tire, the tire comprising: a pair of opposing
bead portions, each bead portion has a bead core and a bead apex at
least one carcass reinforcing ply having radially oriented steel
cords, the at least one carcass reinforcing ply has a main portion
and two turnups, one turnup extending from each end of the main
portion and having a terminal end, the carcass reinforcing ply main
portion extends between the opposing bead cores and turnups are
located axially outward of the bead core and a portion of the bead
apex; and two pairs of polyamide monofilament cord reinforced
chippers, one pair adjacent each turnup, each pair having one inner
chipper being adjacent and on an axially inner side of the turnup
and one outer chipper being adjacent on an axially outer side of
the turnup, the inner and outer chippers adjacent the turnup each
have a terminal end extending radially outward of the terminal end
of the turnup.
2. The pneumatic radial tire of claim 1 wherein the adjacent inner
chipper has the steel cords oriented on a bias angle in relative to
a radial plane of the tire and the adjacent outer chipper has the
steel cords oriented in a bias angle opposite in direction relative
to the inner chipper.
3. The pneumatic radial tire of claim 2 wherein the steel cords of
the chippers are oriented on a bias angle in the range of 25 to 85
degrees.
4. The pneumatic radial tire of claim 3 wherein the steel cords of
the chippers are oriented at equal but oppositely oriented bias
angles.
5. The pneumatic radial tire of claim 1 wherein each chipper has
the steel cords arranged substantially parallel in the range of 8
to 15 ends per inch (3 to 6 ends per cm).
6. The pneumatic radial tire of claim 1 further comprises a second
axially inner chipper having steel cords lying adjacent to and
axially inward of the inner chipper.
7. The pneumatic radial tire of claim 1 further comprises: a belt
reinforcement structure having three or more steel cord reinforced
belt layers disposed radially outward of the at least one carcass
reinforcing ply; and a tread radially outward of the belt
reinforcing structure; and a top belt layer covering the at least
three or more steel cord belt layers, the top belt having cords of
nylon or polyamide.
Description
RELATED APPLICATIONS
[0001] This application is a divisional of co-pending U.S.
application Ser. No. 11/936,241 entitled "Pneumatic Tire" filed
Nov. 7, 2007.
FIELD OF THE INVENTION
[0002] The present invention is directed to a pneumatic tire. More
specifically, the present invention is directed to a pneumatic
radial tire wherein the bead portion of the tire is designed for
improved durability due to the configuration of the turn-up portion
of the carcass reinforcing ply.
BACKGROUND OF THE INVENTION
[0003] Bead area durability is one of the concerns of the tire
industry. A conventional tire bead portion 100 is illustrated in
prior art FIG. 4. What is conventionally considered the main
portion 104 of a carcass reinforcing ply extends radially inward
toward the tire rim and is turned about an inextensible bead core
106 to form a carcass ply turnup 108. The carcass ply turn up 108
extends at a single angle .mu. relative to a radial line tangent to
the axially outermost point of the bead core 106 and parallel to
the tire equatorial plane.
[0004] Due to the configuration and nature of the radial carcass,
when a tire is expanded, the main portion of the carcass is put
under tension, pulling the carcass main portion 104 radially upward
and the carcass turn up 108 radially inward. After inflation and
during operation of the tire, when the tire is under deflection,
the carcass ply is subject to bending forces and the carcass main
portion 104 moves radially inward while the carcass turnup 108
moves radially and axially outward. During both tension and
deflection, the rubber surrounding the carcass main portion 104 and
the carcass turn up 108, due to the adhesion relationship between
the rubber and the reinforcing cords of the ply, also is forced to
move and the rubber is stressed. The movement of the carcass ply
and the surrounding rubber may result in cracking of the rubber in
the tire bead portion, decreasing durability of the tire.
[0005] Other attempts have been made to improve the durability of
the bead portion. U.S. Pat. No. 6,260,597 (Miyazono) discloses a
pneumatic tire having multiple organic fiber cord reinforced layers
in the bead portions outward of a carcass ply. Axially outward of
the carcass ply turnup, the terminal ends of the organic fiber
layers are all at the same height or radially outward of the
terminal end of the carcass ply turnup. Because the axially outer
organic fiber layers are predominately radially outward of the
carcass ply terminal end, when the bead portion is subjected to
strain during operation, it is the organic fiber layer ends that
are subjected to the greater load and where crack initiation may
begin, resulting in reduced bead durability. Miyazono teaches that
to improve durability, the ends of the organic fiber layers are
bent in various different embodiments while the carcass ply turnup
is maintained at a single angle.
[0006] Several prior art patents similarly propose applying textile
cord layers adjacent the turnup ends of a pneumatic tire to improve
durability as in U.S. Pat. No. 4,234,029 and U.S. Pat. No.
4,093,014 having a folded over U shaped chipper. U.S. Pat. No.
6,962,183 uses an axially outer short steel cord chipper
terminating radially below the turnup end wherein both the chipper
and the turnup end are covered by a nylon patch.
[0007] In U.S. Pat. No. 4,842,033 gum strips are proposed to cover
the turnup ends to improve durability.
[0008] In U.S. Pat. No. 6,962,183 and U.S. Pat. No. 6,877,538 the
use of an axially outer steel or organic cord reinforced chipper
layer is taught wherein the outer end terminates below preferably
well below the high ply turnup terminal end which is encased in
insulation rubber.
[0009] All of these exemplary prior art patents where attempts to
improve tire bead area durability and to reduce crack propagation
which is a common issue in heavy duty commercial truck tires,
particularly such tires using a steel reinforced carcass ply.
SUMMARY OF THE INVENTION
[0010] A pneumatic radial tire has a pair of opposing bead
portions, each bead portion has a bead core and a bead apex; at
least one carcass reinforcing ply having radially oriented steel
cords, the at least one carcass reinforcing ply has a main portion
and two turnups, one turnup extending from each end of the main
portion and having a terminal end, the carcass reinforcing ply main
portion extends between the opposing bead cores and turnups are
located axially outward of the bead core and a portion of the bead
apex; and two pairs of steel cord reinforced chippers, one pair
adjacent each turnup, each pair having one inner chipper being
adjacent and on an axially inner side of the turnup and one outer
chipper being adjacent on an axially outer side of the turnup, the
inner and outer chippers adjacent the turnup each have a terminal
end extending radially outward of the terminal end of the
turnup.
[0011] The inner chipper has the steel cords oriented on a bias
angle in relative to a circumferential or radial plane of the tire
and the outer chipper has the steel cords oriented in a bias angle
opposite in direction relative to the inner chipper, the steel
cords of the chippers are oriented on a bias angle in the range of
25 to 85 degrees. The steel cords of the inner and outer chippers
are oriented preferably at equal but oppositely oriented bias
angles. Each chipper has the steel cords arranged substantially
parallel in the range of 8 to 15 ends per inch (3 to 6 ends per
cm). Additionally, a second axially inner chipper having steel
cords lying adjacent to and axially inward of the inner chipper,
may be provided.
[0012] The pneumatic radial tire also has a belt reinforcement
structure having three or more steel cord reinforced belt layers
disposed radially outward of the at least one carcass reinforcing
ply; and a tread radially outward of the belt reinforcing
structure. Preferably, the axially outer chipper extends to a
radially inner end extending between the bead core and a rim
seating base of the bead portion, while the radially outer terminal
end of the axially inner chipper extends outwardly by 5 mm or more
relative to the terminal end of the axially outer chipper. The
radially outer terminal end of the axially outer chipper also
extends outwardly by 5 mm or more relative to the terminal end of
the turnup. The axially inner chipper has a radially inner end
extending toward the bead core terminating above a location of
contact of bead core and the turnup. The pneumatic radial tire of
the present invention is typically a commercial truck tire having
nominal bead diameter of 22.5 inches (88 mm) or greater. In a
second embodiment, two pairs of polyamide monofilament cord
reinforced chippers may be used instead of chippers having steel
cords. Also, the pneumatic radial tire may further be constructed
having a top belt layer covering the at least three or more steel
cord belt layers, the top belt having cords being made of nylon or
polyamide.
DEFINITIONS
[0013] The following definitions are applicable to the present
invention.
[0014] "Inner" means toward the inside of the tire and "outer"
means toward its exterior.
[0015] "Outer" means toward the tire's exterior.
[0016] "Radial" and "radially" are used to mean directions radially
toward or away from the axis of rotation of the tire.
[0017] "Tread" means a molded rubber component which, when bonded
to a tire casing, includes that portion of the tire that comes into
contact with the road when the tire is normally inflated and under
normal load. The tread has a depth conventionally measured from the
tread surface to the bottom of the deepest groove of the tire.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The invention will be described by way of example and with
reference to the accompanying drawings in which:
[0019] FIG. 1 is a cross-sectional view of half of a pneumatic
tire;
[0020] FIG. 2 is a close up of the bead portion of the tire of FIG.
1;
[0021] FIG. 3 is an alternative bead portion construction; and
[0022] FIG. 4 is a prior art tire bead.
DETAILED DESCRIPTION OF THE INVENTION
[0023] The following language is of the best presently contemplated
mode or modes of carrying out the invention. This description is
made for the purpose of illustrating the general principles of the
invention and should not be taken in a limiting sense. The scope of
the invention is best determined by reference to the appended
claims. The reference numerals as depicted in the drawings are the
same as those referred to in the specification. For purposes of
this application, the various embodiments illustrated in the
figures each use the same reference numeral for similar components.
The structures employ basically the same components with variations
in location or quantity thereby giving rise to the alternative
constructions in which the inventive concept can be practiced.
[0024] A pneumatic tire in accordance with a first embodiment of
the present invention is illustrated in FIGS. 1 and 2. The
pneumatic tire has a carcass, a belt structure 8 radially outward
of the carcass, and a tread 10 radially outward of the belt
structure 8. The belt structure 8 may be any of the type
conventionally used for a pneumatic tire, and generally will
include at least two reinforcement plies of angled, inclined cords
and may include a ply of zero degree cords. The actual belt
structure of the tire will be dictated by the intended end use of
the tire. Similarly, the exact tread configuration will be dictated
by the intended end use of the tire.
[0025] The carcass has at least one carcass reinforcing ply 12, a
pair of opposing bead portions 14 and a pair of opposing sidewalls
16. The ply 12 has a main portion 18 extending through the opposing
sidewalls 16 and two carcass turnups 20 initiating in the bead
portions 14. Each carcass turnup 20 of the carcass reinforcing ply
12 extends from the main portion 18 of the carcass reinforcing ply
12, and is wrapped about a bead core 23 and a bead apex 24 in the
bead portion 14; thus enveloping, at a minimum, the bead core 23
and the lower portion of the bead apex 24 in each bead portion 14.
The carcass turnup 20 terminates at a distance H.sub.T from the
tire bead base line BL; the distance H.sub.T is at least 20% of the
section height SH. The tire bead base line BL is an imaginary line,
perpendicular to the equatorial plane EP of the tire, from the
intersection of the radially extending outer side of the bead
portion and the bead base of the tire.
[0026] Outward of the carcass ply 12 in the bead portion 14 is a
steel cord reinforced layer referred to as the axially outer
chipper 30. The axially outer chipper 30 extends from axially
inward of the bead core 23 to axially outward of the bead core 23,
being turned up around the bead core 23 similar to the carcass ply
12. The radially outer end 31 of the outer chipper 30 terminates
radially outward of the terminal end 21 of the turnup 20 of the
carcass ply 12. The axially outer chipper 30 extends radially
inwardly along and adjacent to the turnup 20 and wraps about a
portion of the bead core 23 and the carcass ply 12 terminating at
an axially inner end 33 between the bead core 23 and a rim seating
bead base 26.
[0027] To reduce the effect of the shear forces acting on both the
carcass main portion 18 and the turnup portion 20, the minimum
distance D.sub.min between the carcass main portion 18 and the
carcass turnup 20, as measured perpendicular to the EP, is not less
than 50%, preferably not less than 75% of the maximum bead core
width W.sub.B as measured perpendicular to the EP. Preferably, to
maintain the spacing, the carcass turnup 20 also does not pass
axially inward of a radial line BT that is tangent to the axially
outermost point of the bead core 23 and parallel to the tire
equatorial plane EP.
[0028] Outward of the main portion 18 of the carcass ply 12 in the
bead portion 14 is another steel cord reinforced layer referenced
to as the axially inner chipper 40. The axially inner chipper 40
extends from a radially inner end 43 located above and in close
proximity to the bead core 23. The axially inner chipper 40 extends
axially inward along and adjacent to the turnup 20 extending to a
radially outer end 41 which extends radially outward of both the
terminal end 21 of the turnup 20 and the radially outer end 31 of
the axially outer chipper 30.
[0029] As shown in both FIGS. 1 and 2, the axially outer chipper 30
has the end 31 extending 5 mm or more beyond the terminal end 21 of
the turnup 20, while the inner chipper 40 extends even further
beyond both the terminal end 21 and the end 31 to an end 41 which
extends at least 5 mm or more beyond the end 31. In this region the
radially outer portions of the inner chipper 40 and the outer
chipper 30 join creating an interlocking adjoining region just
radially above the terminal end 21 of the ply turnup 20.
[0030] Both the inner and outer chippers 30, 40 are reinforced with
substantially inextensible cords 32, 42. Preferably the cords 32,
42 are made of steel having a mesh of parallel cords between about
8 and 18 ends per inch, preferably between about 12 and 16 ends per
inch. The wire cord gauge of each chipper is preferably between
about 0.6 mm and 1.5 mm. The chipper cords 32, 42 are oriented at
an angle of between about 25 degrees and about 85 degrees with
respect to the radially oriented steel cords 22 that reinforce the
ply 20, most preferably cords 32, 42 are oriented between 25 and
about 45 degrees. Alternatively the cords 32, 42 can be made of a
polyamide monofilament cord of any cross sectional shape such as
round, oval or star. These polyamide cords 32, 42 although being a
synthetic material are very strong and similarly substantially
inextensible as compared to polyester or nylon cords.
[0031] Both chipper layers 30, 40 when assembled as shown
preferably have generally equal, but oppositely oriented cord
angles. By having the cord angles biased oppositely at the
locations where the chipper 30 and 40 are joined causes the
stresses that would normally tend to initiate a crack at the
terminal end 21 of the ply turnup 20 absorbed first by the end 41
of the axially inner chipper 40 causing these shear stresses to
progress radially inwardly to the area wherein the outer chipper 30
is joined to the inner chipper 40 causing the shear forces to be
absorbed in both the chippers 30 and 40 directly above the turnup
20. This greatly lowers the shear forces absorbed by the turnup 20
while also providing a way in which the inner chipper 40, can in a
disconnected way relative to the bead core 23, transfer the stress
to the outer chipper 30 which is anchored between the bead core 23
and bead base 26 without unduly loading the turnup 20. Textile or
otherwise high elongation cords used to protect the turnup 20 could
not absorb nor transfer the shear stresses in such an efficient
manner. The stretching of such textile cords would simply cause the
turnup 20 when reinforced with steel cords 22 to absorb the shear
forces and the typical cracking in this area of the bead 14 would
continue to occur.
[0032] An important feature of the present invention is the fact
that the initial forces are absorbed by the inner chipper 40
because of its end 41 extending above the end 31. This structure
insures the inner chipper 30, unanchored by the bead core 23, takes
the initial shear stresses caused by deflection of the tire.
Attempts to extend the end 31 of the outer chipper 30 to the same
height or beyond the end 41 of the inner chipper 40 would have
caused the anchored outer chipper 30 to take the initial shear
stress and its end 31 would initiate a crack propagation due to the
stiffness of the steel or polyamide cords 32 being anchored at the
bead core 23. The present invention insures the stresses due to
deflection of the tire are first taken in the longer end 41 of the
chipper 40.
[0033] With reference to FIG. 3 an alternative embodiment bead
portion 14 is shown wherein an additional second inner chipper 50
is added to the bead portion 14. The second chipper 50 has a radial
outer end 51 and radial end 53 lying adjacent next to the inner
chipper 40. The second inner chipper 50 has steel or polyamide
cords 52 oriented on a bias angle preferably equal but opposite to
the cords 42 of the inner chipper 40. In this alternative
embodiment the added chipper 50 increases the stiffness of the bead
portion 14 inward of the ply turnup 20 to further insure the
transfer of shear stresses along both the inner chippers 40, 50 and
outer chipper 30.
[0034] In each of the present tire construction, the primary
advantage is increasing bead durability under heavy loads or high
heat conditions as is seen in commercial vehicles such as buses,
tractors and medium commercial truck tires designed for heavy
loads. Such tires typically have large rim diameters of 22.5 inches
(88 mm) or greater and are designed to be retreaded such that the
bead portions of the carcass may be exposed to many hundreds of
thousand miles. The ability to provide a more durable bead portion
as is accomplished by the present invention provides a more
reliable longer lasting carcass.
[0035] As shown by sandwiching the ply turnup 20 between the
chippers 30 and 40 or optionally, also chipper 50, the present
invention has been shown to enable the bead area to actually be
made slightly lighter in weight which helps reduce hear build up.
In a preferred embodiment the main portion 18 of the ply 12
preferably has a ply line approximately a neutral ply path to
further help reduce shear forces on the ply 12. Experimental
testing has shown the bead portions 14 employing the chippers 30,
40 provide a cool running tire with lower shear stresses along the
ply turnup 20 evidencing greatly improved bead area durability with
a much lower probability of end cracking along the ply turnup
terminal end 21.
[0036] The tire of the present invention has an improved life and
improved bead durability. The teachings herein are applicable to a
broad range of tires and may be useful in tire lines such as, but
not limited to, passenger tires, radial medium truck tires,
aircraft tires, and off-the-road tires. The teachings may also be
useful in improving bead durability for run-flat tires of any
type.
[0037] Variations in the present invention are possible in light of
the description of it provided herein. While certain representative
embodiments and details have been shown for the purpose of
illustrating the subject invention, it will be apparent to those
skilled in this art that various changes and modifications can be
made therein without departing from the scope of the subject
invention. It is, therefore, to be understood that changes can be
made in the particular embodiments described which will be within
the full intended scope of the invention as defined by the
following appended claims.
* * * * *