U.S. patent application number 16/429931 was filed with the patent office on 2019-09-19 for beadless non-pneumatic tire with geodesic ply.
The applicant listed for this patent is The Goodyear Tire & Rubber Company. Invention is credited to James Alfred BENZING, II, Daniel Ray DOWNING.
Application Number | 20190283502 16/429931 |
Document ID | / |
Family ID | 57542877 |
Filed Date | 2019-09-19 |
United States Patent
Application |
20190283502 |
Kind Code |
A1 |
BENZING, II; James Alfred ;
et al. |
September 19, 2019 |
BEADLESS NON-PNEUMATIC TIRE WITH GEODESIC PLY
Abstract
A structurally supported tire includes a ground contacting
annular tread portion, an annular shear band and geodesic ply.
Inventors: |
BENZING, II; James Alfred;
(North Canton, OH) ; DOWNING; Daniel Ray;
(Uniontown, OH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
The Goodyear Tire & Rubber Company |
Akron |
OH |
US |
|
|
Family ID: |
57542877 |
Appl. No.: |
16/429931 |
Filed: |
June 3, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15275753 |
Sep 26, 2016 |
10350945 |
|
|
16429931 |
|
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|
62270763 |
Dec 22, 2015 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B60C 7/00 20130101; B60C
7/26 20130101; B60C 2007/146 20130101; B60C 7/24 20130101; B60C
7/102 20130101; B60C 7/14 20130101 |
International
Class: |
B60C 7/10 20060101
B60C007/10; B60C 7/24 20060101 B60C007/24; B60C 7/26 20060101
B60C007/26; B60C 7/00 20060101 B60C007/00; B60C 7/14 20060101
B60C007/14 |
Claims
1. A non-pneumatic tire comprising a ground contacting annular
tread portion; a shear band; a connecting web formed of a plurality
of strips of fabric extending between a first radius and a second
radius, wherein a first end of the reinforcement layer is
positioned in the shear band, and a second end is positioned
adjacent to the first end, and a mid portion is secured to the rim.
Description
FIELD OF THE INVENTION
[0001] The present invention relates generally to vehicle tires and
non-pneumatic tires, and more particularly, to a non-pneumatic
tire.
BACKGROUND OF THE INVENTION
[0002] The pneumatic tire has been the solution of choice for
vehicular mobility for over a century. The pneumatic tire is a
tensile structure. The pneumatic tire has at least four
characteristics that make the pneumatic tire so dominate today.
Pneumatic tires are efficient at carrying loads, because all of the
tire structure is involved in carrying the load. Pneumatic tires
are also desirable because they have low contact pressure,
resulting in lower wear on roads due to the distribution of the
load of the vehicle. Pneumatic tires also have low stiffness, which
ensures a comfortable ride in a vehicle. The primary drawback to a
pneumatic tire is that it requires compressed fluid. A conventional
pneumatic tire is rendered useless after a complete loss of
inflation pressure.
[0003] A tire designed to operate without inflation pressure may
eliminate many of the problems and compromises associated with a
pneumatic tire. Neither pressure maintenance nor pressure
monitoring is required. Structurally supported tires such as solid
tires or other elastomeric structures to date have not provided the
levels of performance required from a conventional pneumatic tire.
A structurally supported tire solution that delivers pneumatic
tire-like performance would be a desirous improvement.
[0004] Non pneumatic tires are typically defined by their load
carrying efficiency. "Bottom loaders" are essentially rigid
structures that carry a majority of the load in the portion of the
structure below the hub. "Top loaders" are designed so that all of
the structure is involved in carrying the load. Top loaders thus
have a higher load carrying efficiency than bottom loaders,
allowing a design that has less mass.
[0005] Thus an improved non pneumatic tire is desired that has all
the features of the pneumatic tires without the drawback of the
need for air inflation is desired.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] The present invention will be better understood through
reference to the following description and the appended drawings,
in which:
[0007] FIG. 1 is a perspective view of a first embodiment of a
non-pneumatic tire of the present invention;
[0008] FIG. 2 is a perspective view of a second embodiment of a
non-pneumatic tire of the present invention;
[0009] FIG. 3 is a cross-sectional view of the non-pneumatic of
FIG. 1 or FIG. 2;
[0010] FIG. 4 is a cross-sectional view of the non-pneumatic of
FIG. 1 or FIG. 2 having a double reinforcement layer;
[0011] FIG. 5 is a close up side view of the tire of FIG. 1 having
geodesic ply spokes.
[0012] FIG. 6 is a perspective view of an embodiment of the
invention with geodesic ply spokes;
[0013] FIG. 7 is a side view of a third embodiment of the invention
with geodesic ply spokes having a turnup.
[0014] FIG. 8a is a cross-sectional view of the invention showing
the ply positioned in the shear band between the reinforcement
layers of the shear band.
[0015] FIG. 8B illustrates an alternate embodiment of the ply
clamped around an optional elastic member.
[0016] FIG. 9 illustrates a fourth embodiment of the invention.
[0017] FIG. 10 is a cross-sectional view of the invention showing
ply spokes embedded in the shear band.
[0018] FIG. 11a illustrates a spring rate test for a shear band,
while FIG. 11b illustrates the spring rate k determined from the
slope of the force displacement curve.
[0019] FIG. 12 is the deflection measurement on a shear band from a
force F.
DEFINITIONS
[0020] The following terms are defined as follows for this
description.
[0021] "Equatorial Plane" means a plane perpendicular to the axis
of rotation of the tire passing through the centerline of the
tire.
[0022] "Meridian Plane" means a plane parallel to the axis of
rotation of the tire and extending radially outward from said
axis.
[0023] "Hysteresis" means the dynamic loss tangent measured at 10
percent dynamic shear strain and at 25.degree. C.
DETAILED DESCRIPTION OF THE INVENTION
[0024] A non-pneumatic tire 100 of the present invention is shown
in the enclosed figures. The non-pneumatic tire of the present
invention includes a radially outer ground engaging tread 200, a
shear band 300, and one or more reinforcement layer 400. The
non-pneumatic tire of the present invention is designed to be a top
loaded structure, so that the shear band 300 and the reinforcement
layer 400 efficiently carries the load. The shear band 300 and the
reinforcement layer 400 are designed so that the stiffness of the
shear band is directly related to the spring rate of the tire. The
reinforcement layer is designed to be a stiff structure that
buckles or deforms in the tire footprint and does not compress or
carry a compressive load. This allows the rest of structure not in
the footprint area the ability to carry the load, resulting in a
very load efficient structure. It is desired to minimize this load
for the reason above and to allow the shearband to bend to overcome
road obstacles. The approximate load distribution is such that
approximately 95-100% of the load is carried by the shear band and
the upper radial portion of the reinforcement layer 400, so that
the lower portion of the reinforcement structure undergoing
compression carries virtually zero of the load, and preferably less
than 10%.
[0025] The tread portion 200 may be a conventional tread as
desired, and may include grooves or a plurality of longitudinally
oriented tread grooves forming essentially longitudinal tread ribs
there between. Ribs may be further divided transversely or
longitudinally to form a tread pattern adapted to the usage
requirements of the particular vehicle application. Tread grooves
may have any depth consistent with the intended use of the tire.
The tire tread 200 may include elements such as ribs, blocks, lugs,
grooves, and sipes as desired to improve the performance of the
tire in various conditions.
Shear Band
[0026] The shear band 300 is preferably annular. A cross-sectional
view of the shear band is shown in FIG. 3. The shear band 300 is
located radially inward of the tire tread 200. The shear band 300
includes a first and second reinforced elastomer layer 310,320. In
a first embodiment of a shear band 300, the shear band is comprised
of two inextensible reinforcement layers 310,320 arranged in
parallel, and separated by a shear matrix 330 of elastomer. Each
inextensible layer 310,320 may be formed of parallel inextensible
reinforcement cords 311,321 embedded in an elastomeric coating. The
reinforcement cords 311,321 may be steel, aramid, nylon, polyester
or other inextensible structure. The shear band 300 may further
optionally include a third reinforced elastomer layer 340 (not
shown) located between the first and second reinforced elastomer
layers 310,320.
[0027] It is additionally preferred that the outer lateral ends
302,304 of the shear band be radiused in order to control the
buckled shape of the sidewall and to reduce flexural stresses.
[0028] In the first reinforced elastomer layer 310, the
reinforcement cords are oriented at an angle .PHI. in the range of
0 to about +/-10 degrees relative to the tire equatorial plane. In
the second reinforced elastomer layer 320, the reinforcement cords
are oriented at an angle .phi. in the range of 0 to about +/-10
degrees relative to the tire equatorial plane. Preferably, the
angle .PHI. of the first layer is in the opposite direction of the
angle .phi. of the reinforcement cords in the second layer. That
is, an angle +.PHI. in the first reinforced elastomeric layer and
an angle -.phi. in the second reinforced elastomeric layer.
[0029] The shear matrix 330 may have a radial thickness in the
range of about 0.10 inches to about 0.2 inches, more preferably
about 0.15 inches. The shear matrix is preferably formed of an
elastomer material having a shear modulus G.sub.m in the range of
15 to 80 MPa, and more preferably in the range of 40 to 60 MPA.
[0030] The shear band has a shear stiffness GA. The shear stiffness
GA may be determined by measuring the deflection on a
representative test specimen taken from the shear band. The upper
surface of the test specimen is subjected to a lateral force F as
shown below. The test specimen is a representative sample taken
from the shear matrix material, having the same radial
thickness.
[0031] The shear stiffness GA is then calculated from the following
equation:
GA=F*L/.DELTA.X
[0032] The shear band has a bending stiffness EI. The bending
stiffness EI may be determined from beam mechanics using the three
point bending test subjected to a test specimen representative of
the shear band. It represents the case of a beam resting on two
roller supports and subjected to a concentrated load applied in the
middle of the beam. The bending stiffness EI is determined from the
following equation: EI=PL.sup.3/48*.DELTA.X, where P is the load, L
is the beam length, and .DELTA.X is the deflection.
[0033] It is desirable to maximize the bending stiffness of the
shearband EI and minimize the shear band stiffness GA. The
acceptable ratio of GA/EI would be between 0.01 and 20, with a
preferred range between 0.01 and 5. EA is the extensible stiffness
of the shear band, and it is determined experimentally by applying
a tensile force and measuring the change in length. The ratio of
the EA to EI of the shearband is acceptable in the range of 0.02 to
100 with a preferred range of 1 to 50. The shear band 300
preferably can withstand a maximum shear strain in the range of
15-30%.
[0034] The shear band 300 has a spring rate k that may be
determined experimentally by exerting a downward force on a
horizontal plate at the top of the shear band and measuring the
amount of deflection as shown in FIG. 11a. The spring rate k is
determined from the slope of the Force versus deflection curve, as
shown in FIG. 11b.
[0035] The non-pneumatic tire has an overall spring rate k.sub.t
that is determined experimentally. The non-pneumatic tire is
mounted upon a rim, and a load is applied to the center of the tire
through the rim. The spring rate k.sub.t is determined from the
slope of the Force versus deflection curve. The spring rate k.sub.t
is preferably in the range of 500 to 1000 for small low speed
vehicles such as lawn mowers.
[0036] The invention is not limited to the shear band structure
disclosed herein, and may comprise any structure which has a GA/EI
in the range of 0.01 to 20, or a EA/EI ratio in the range of 0.02
to 100, or a spring rate k.sub.t in the range of 500 to 1000, as
well as any combinations thereof. More preferably, the shear band
has a GA/EI ratio of 0.01 to 5, or an EA/EI ratio of 1 to 50 and
any subcombinations thereof. The tire tread is preferably wrapped
about the shear band and is preferably integrally molded to the
shear band.
Reinforcement Structure
[0037] A first embodiment of the non-pneumatic tire of the present
invention is shown in FIG. 2. The reinforcement structure 400
functions to carry the load transmitted from the shear layer. The
reinforcement structure 400 is primarily loaded in tension and
shear, and carries no load in compression. As shown in FIGS. 2 and
3, the reinforcement layer 400 has a first end 402a,b that extends
from a first radius to a second radius in order to form the
non-pneumatic tire sidewall. At the first radius, the first end
402a,b is clamped to a rim via clamp rings 500 connected to the
rim, as shown in FIG. 3, without the need for a bead. Each first
end 402a,b extends radially outward and terminates in a respective
second end 405a,b. As shown in FIG. 3, the reinforcement layer
extends radially outward of the shear band 300 and terminates
axially inward of the lateral edges 302,304 of the shear band. Thus
the sidewall may be formed from one or more reinforcement layers.
The second end 405a,b may optionally extend completely across the
crown of the tire, although not required, as shown in FIG. 4.
[0038] The reinforcement layer 400 may comprise any fabric or
flexible structure such as nylon, polyester, cotton, rubber.
Preferably, the reinforcement layer 400 comprises a reinforced
rubber or ply layer formed of parallel reinforcements that are
nylon, polyester or aramid. Preferably, the reinforcements are
oriented in the radial direction. It is preferred that tire ply be
used as a reinforcement layer for several reasons. First, tire ply
is an ideal connecting structure for the non-pneumatic tire
application because it is thin, and has a low bending stiffness
with no resistance to compression or buckling. Tire ply has a high
tensile stiffness and strength which is needed in the non-pneumatic
tire application. Tire ply is also cheap, has a known durability,
and is readily available. Furthermore, a continuous ply
reinforcement layer eliminates debris which can be caught into
spoke or web non pneumatic tire designs, and does not contribute to
tire noise or high frequency harmonics associated with discrete
spokes.
[0039] The reinforcement layer forming the sidewalls is preferably
oriented so that it makes an angle alpha with respect to the radial
direction, as shown in FIG. 3. The angle alpha can help pretension
the reinforcement 400 and also increase and tune the lateral
stiffness of the tire. This results in a non-pneumatic tire having
angled sidewalls. The angle alpha is measured with respect to the
radial direction, and may be -10 to 45 degrees, and more
preferably, 0 to 45 degrees, and even more preferably 10-25 degrees
as measured with respect to the radial direction. The angle alpha
can be tuned as desired using an axial adjustment feature of the
rim 502. The rim 502 may be axially adjusted to narrow or expand
the axial rim width. This axial adjustment controls the ply
tension, allowing the tire lateral stiffness to be adjusted
independent of the radial stiffness. The rim may be adjusted by a
tensioning member or bolt 504 that is mounted in the opposed rim
parallel walls 506,508. The clamp rings 500 are secured to the
outer end of the rim walls 506,508. Alternatively, the angle may be
adjusted by the radial length of the sidewalls.
[0040] FIG. 1 illustrates a second embodiment of the invention
wherein the reinforcement layer is formed by a plurality of strips
401, that are preferably geodesic, and more preferably the strips
are oriented in the radial direction. The strips are preferably
about 0.25 to 0.5 inches wide. Each strip preferably includes one
or more parallel reinforcements, such as nylon, polyester or aramid
reinforcements which are preferably oriented in the radial
direction when mounted on the tire. FIG. 3 is representative of the
cross-section of FIG. 1, wherein the strips may be arranged in a
single reinforcement layer. The strips may overlap as shown in FIG.
5. Alternatively, the reinforcement structure 400 may comprise two
or more layers of reinforcement for the embodiments of FIG. 1 or 2
as shown in FIG. 4,5. As shown in FIG. 4, the ply layer has a first
inner layer 400 that extends completely (axially) across the crown
portion of the tire, and is located radially outward of the shear
band 300. The inner ply layer 400 extends radially inward and forms
a looped end 402a,b that is clamped or secured to the rim, wherein
the ply forms a second layer that extends radially outward of the
rim clamps and then radially outward of the shear band terminating
in folded over ends 408a,b. Thus the sidewalls are formed of a dual
layer of reinforcement ply. An optional flexible o-ring or flexible
rubber band 800 may be used to form the looped end, as shown in
FIG. 6, wherein the flexible o-ring 800 and ply ends are then
securing to rim clamps 500 as shown in FIG. 8b.
[0041] Alternatively, the reinforced ply strip may be continuously
wound from one side of the tire to the other in order to form a
plurality of geodesic ply spokes. The reinforced strips are wound
in a continuous manner so that the geodesic ply spokes extend from
the inner radius R1 to the outer radius R2, as shown in FIG. 8a.
Preferably, the ply spokes are oriented in the radial direction.
The reinforced strip may optionally extend over the full axial
width of the crown and then radially inward to form the other
sidewall. The ply spokes or strip are preloaded in tension.
[0042] Alternatively, the first end 402a,b may be wound around a
portion of the rim, or otherwise secured or fastened to the outer
radial portion of the rim.
[0043] Alternatively, the first end 402a,b may be looped around a
portion of the rim and secured to the down portion of the ply
forming a looped end or beadless turnup as shown in FIG. 7. The
looped end may be received in clamps and may further include an
optional annular flexible member 800 mounted on the rim. The
optional flexible member 800 may be an o-ring or flexible rubber
band, which may be included to facilitate the mounting of the
reinforcement structure on the rim clamp as shown in FIG. 6 and
FIG. 8b. Thus the invention has eliminated the need for a bead or
annular tensile member, which reduces the weight, cost and
complexity of the design.
[0044] The reinforcement structure 400 need not be positioned
radially outward of the shear band. The reinforcement structure may
be positioned radially inward of the shear band, and underneath the
shear band as shown in FIG. 9. Alternatively, a portion of the
reinforcement layer may even be positioned between the
reinforcement layers of the shear band, as shown in FIG. 8A.
However, it is advantageous to locate the reinforcement layer
radially outward of the shear band because it eliminates the
tensile stress on the bond between the shear band and load carrying
member or connecting structure. This advantage is especially
important when the shear band and the play are dissimilar
materials.
[0045] Alternatively as shown in FIG. 10, a first end 432 of a ply
spoke may terminate in the crown portion of the tire and in the
shear band, and the terminal end 431 of the ply spoke may partially
extend up the sidewall of the tire.
[0046] Applicants understand that many other variations are
apparent to one of ordinary skill in the art from a reading of the
above specification. These variations and other variations are
within the spirit and scope of the present invention as defined by
the following appended claims.
* * * * *