U.S. patent application number 15/798450 was filed with the patent office on 2018-02-22 for structurally supported tire.
The applicant listed for this patent is The Goodyear Tire & Rubber Company. Invention is credited to James Alfred BENZING, II, Daniel Ray DOWNING, Joseph Carmine LETTIERI.
Application Number | 20180050567 15/798450 |
Document ID | / |
Family ID | 59018883 |
Filed Date | 2018-02-22 |
United States Patent
Application |
20180050567 |
Kind Code |
A1 |
BENZING, II; James Alfred ;
et al. |
February 22, 2018 |
STRUCTURALLY SUPPORTED TIRE
Abstract
A structurally supported tire includes a ground contacting
annular tread portion, an annular hoop structure for supporting a
load on the tire, a means for attachment to a vehicle rim, and a
ply structure secured to a first axial limit and extending radially
outward and between the hoop structure and the tread portion and
further extending radially inward from between the hoop structure
and tread portion to a second axial limit. The ply structure is
secured to both the first axial limit and the second axial limit.
The tread portion is secured to a radially outer surface of the ply
structure. The hoop structure is secured to a radially inner
surface of the ply structure.
Inventors: |
BENZING, II; James Alfred;
(North Canton, OH) ; DOWNING; Daniel Ray;
(Uniontown, OH) ; LETTIERI; Joseph Carmine;
(Hudson, OH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
The Goodyear Tire & Rubber Company |
Akron |
OH |
US |
|
|
Family ID: |
59018883 |
Appl. No.: |
15/798450 |
Filed: |
October 31, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
14965248 |
Dec 10, 2015 |
9834040 |
|
|
15798450 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B60C 7/24 20130101; B60C
7/18 20130101; B60C 7/22 20130101; B60C 7/00 20130101; B60C 7/06
20130101 |
International
Class: |
B60C 7/00 20060101
B60C007/00; B60C 7/24 20060101 B60C007/24; B60C 7/06 20060101
B60C007/06 |
Claims
1-16. (canceled)
17. A method for non-pneumatically supporting a load comprising the
steps of: securing a single ply structure to a vehicle rim;
clamping the single ply structure to the vehicle rim; extending the
single ply structure from the vehicle rim to a radially outer
surface of a hoop structure; further extending the single ply
structure from the radially outer surface of the hoop structure to
the vehicle rim; securing the single ply structure to the vehicle
rim; and supporting the load by a compressive hoop strength of the
hoop structure and a tensile strength of part of the ply
structure.
18. The method as set forth in claim 16 further including the step
of stretching the ply structure up over the hoop structure.
19. The method as set forth in claim 16 further including the step
of decreasing an axial distance between a first part of the vehicle
rim and a second part of the vehicle rim such that the axial
distance is less than an axial width of the tread portion.
20. The method as set forth in claim 16 further including the step
of attaching the ply structure to a radially outer surface of the
hoop structure.
21. The method as set forth in claim 16 further including the step
of attaching a tread portion to a radially outer surface of the ply
structure.
Description
FIELD OF THE INVENTION
[0001] The present invention relates generally to vehicle tires and
wheels, and more particularly, to non-pneumatic tire/wheel
assemblies.
BACKGROUND OF THE INVENTION
[0002] The pneumatic tire has been the solution of choice for
vehicular mobility for over a century. Modern belted, radial
carcass, pneumatic tires are remarkable products that provide an
effective means for supporting applied loads while allowing
reasonable vertical and lateral compliance. The pneumatic tire
obtains its mechanical attributes largely due to the action of
internal air pressure in the tire cavity. Reaction to the inflation
pressure corrects rigidities to the belt and carcass components.
Inflation pressure is then one of the most important design
parameters for a pneumatic tire.
[0003] Good pressure maintenance is required to obtain the best
performance from a pneumatic tire. Inflation pressure below that
specified can result in a loss of fuel economy. Of primary
importance is that a conventional pneumatic tire is capable of very
limited use after a complete loss of inflation pressure. Many tire
constructions have been proposed for continued mobility of a
vehicle after a complete loss of air pressure from the tire.
Commercially available runflat tire solutions are pneumatic tires
having added sidewall reinforcements or fillers to permit the
sidewalls to act in compression as load supporting members during
deflated operation. This added reinforcement often results in the
disadvantages of higher tire mass and reduced riding comfort. Other
attempts to provide runflat capability utilize essentially annular
reinforcing bands in the tire crown portion. In these solutions,
the rigidity of the tread portion results partly from the inherent
properties of the annular reinforcing band and partly from the
reaction to inflation pressure. Still other solutions rely on
secondary internal support structures attached to the wheel. These
supports add mass to the mounted assembly and either increase
mounting difficulty or may require the use of multiple piece rims.
All of these approaches are hybrids of an otherwise pneumatic tire
structure and suffer from design compromises that are optimal for
neither the inflated nor deflated states. In addition, these
runflat solutions require the use of some means to monitor tire
inflation pressure and to inform the vehicle operator if the
inflation pressure is outside the recommended limits.
[0004] 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.
SUMMARY OF THE INVENTION
[0005] A structurally supported tire in accordance with the present
invention includes a ground contacting annular tread portion, an
annular hoop structure for supporting a load on the tire, a means
for attachment to a vehicle rim, and a ply structure secured to a
first axial limit and extending radially outward and between the
hoop structure and the tread portion and further extending radially
inward from between the hoop structure and tread portion to a
second axial limit. The ply structure is secured to both the first
axial limit and the second axial limit. The tread portion is
secured to a radially outer surface of the ply structure. The hoop
structure is secured to a radially inner surface of the ply
structure.
[0006] According to another aspect of the tire, inner radii of the
ply structure are attached to the vehicle rim through two
mechanical clamps each capturing a part of the ply structure.
[0007] According to still another aspect of the tire, inner radii
of the ply structure are attached to the vehicle rim through
mechanical clamps and a clamping force is strengthened by adding
rings around which the ply structure is folded.
[0008] According to yet another aspect of the tire, an axial
distance between the first axial limit and the second axial limit
is decreased by an adjustment mechanism so that the axial distance
is less than an axial width of the tread portion.
[0009] According to still another aspect of the tire, the hoop
structure is constructed of multiple layers allowing shear strain
between the multiple layers.
[0010] According to yet another aspect of the tire, the hoop
structure comprises a first layer of reinforcing cords extending at
an angle of between -5.degree. to +5.degree. relative to the
circumferential direction of the tire.
[0011] According to still another aspect of the tire, the hoop
structure comprises a second layer of reinforcing steel cords
extending at an angle of between -5.degree. to +5.degree. relative
to the circumferential direction of the tire.
[0012] According to yet another aspect of the tire, the hoop
structure comprises a third layer of elastic construction for
absorbing shear strain between the first layer and the second
layer.
[0013] According to still another aspect of the tire, the third
layer consists of a homogenous polymer material.
[0014] A structurally supported tire and rim assembly in accordance
with the present invention includes a ground contacting annular
tread portion, an annular hoop structure for supporting a load on a
tire, a means for attachment to a vehicle rim, and a ply structure
secured to a first axial limit of the vehicle rim and extending
radially outward to adjacent the hoop structure and further
extending radially inward from adjacent the hoop structure to a
second axial limit of the vehicle rim, the ply structure being
secured to both the first axial limit of the vehicle rim and the
second axial limit of the vehicle rim, the tread portion being
secured proximate the hoop structure.
[0015] According to another aspect of the assembly, the ply
structure includes a plurality of strips of material extending
between the vehicle rim and a position adjacent the hoop
structure.
[0016] According to still another aspect of the assembly, the ply
structure consists of one single strip of material extending
repeatedly between the vehicle rim and positions adjacent the hoop
structure.
[0017] According to yet another aspect of the assembly, the hoop
structure defines a shear band having a first layer, a second
layer, and a third layer. The first and second layers have
reinforcing cords extending at an angle of between -5.degree. to
+5.degree. relative to the circumferential direction of the
tire.
[0018] According to still another aspect of the assembly, the third
layer has an elastic construction for absorbing shear strain
between the first layer and the second layer.
[0019] Another structurally supported tire in accordance with the
present invention includes a ground contacting annular tread
portion, an annular hoop structure for supporting a load on a tire,
a means for attachment to a vehicle rim, a ply structure secured to
a first axial limit and extending radially outward to adjacent the
hoop structure and further extending radially inward from adjacent
the hoop structure to a second axial limit, the ply structure being
secured to both the first axial limit and the second axial limit,
and an adjustment mechanism for varying an axial distance between
the first axial limit and the second axial limit, the tread portion
being secured proximate the hoop structure.
[0020] According to another aspect of the other tire, the
adjustment mechanism includes a threaded bolt and at least two nuts
threadedly engaging the threaded bolt.
[0021] A method in accordance with the present invention
non-pneumatically supports a load. The method includes the steps
of: securing a single ply structure to a vehicle rim; clamping the
single ply structure to the vehicle rim; extending the single ply
structure from the vehicle rim to a radially outer surface of a
hoop structure; further extending the single ply structure from the
radially outer surface of the hoop structure to the vehicle rim;
securing the single ply structure to the vehicle rim; and
supporting the load by a compressive hoop strength of the hoop
structure and a tensile strength of part of the ply structure.
[0022] According to another aspect of the method, a further step
includes stretching the ply structure up over the hoop
structure.
[0023] According to still another aspect of the method, a further
step includes decreasing an axial distance between a first part of
the vehicle rim and a second part of the vehicle rim such that the
axial distance is less than an axial width of the tread
portion.
[0024] According to yet another aspect of the method, a further
step includes attaching the ply structure to a radially outer
surface of the hoop structure.
[0025] According to still another aspect of the method, a further
step includes attaching a tread portion to a radially outer surface
of the ply structure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] The present invention will be better understood through
reference to the following description and the appended drawings,
in which:
[0027] FIG. 1 is a schematic cross section view of a tire/wheel
assembly in accordance with the present invention;
[0028] FIG. 2 is a schematic elevation taken along line "2-2" in
FIG. 1, with a one layer ply;
[0029] FIG. 3 is a schematic cross section view of another
tire/wheel assembly in accordance with the present invention;
and
[0030] FIG. 4 is a schematic elevation taken along line "2-2" in
FIG. 3, with a two layer ply.
DEFINITIONS
[0031] The following terms are defined as follows for this
description.
[0032] "Equatorial Plane" means a plane perpendicular to the axis
of rotation of the tire passing through the centerline of the
tire.
[0033] "Meridian Plane" means a plane parallel to the axis of
rotation of the tire and extending radially outward from said
axis.
[0034] "Bending Stiffness" of the shear band EI. The bending
stiffness EI may be determined from beam mechanics using a three
point bending test. EI may represent a beam resting on two roller
supports and subjected to a concentrated load applied in the middle
of the beam. The bending stiffness EI may be determined from the
following equation: EI=PL3/48*.DELTA.X, where P is the load, L is
the beam length, and .DELTA.X is the deflection.
[0035] "Extensional Stiffness" of the shear band EA. The
extensional stiffness EA may be is determined by applying a tensile
force in the circumferential direction of the shear band and
measuring the change in length.
[0036] "Hysteresis" means the dynamic loss tangent measured at 10
percent dynamic shear strain and at 25.degree. C.
DETAILED DESCRIPTION OF EXAMPLE OF THE PRESENT INVENTION
[0037] Conventional structurally supported tires may support a load
without the support of gas inflation pressure. Such a tire may have
a ground contacting tread portion, sidewall portions extending
radially inward from the tread portion and bead portions at the end
of the sidewall portions. The bead portions may anchor the tire to
a vehicle wheel. The tread portion, sidewall portions, and bead
portions may define a hollow, annular space. Alternately, the bead
portion and the tread portion may be connected in the radial
direction by a conventional connecting web, which may consist of a
number of different geometries. These geometries may include a
plurality of radial spokes or a network of polygons, such as
hexagons.
[0038] One conventional structurally supported tire may have a
connecting web or sidewall portion attached thereto. Such a
connecting web or sidewall structure does not extend radially
beyond a radially inward side of the first membrane. This
attachment may be achieved through an adhesive bond. Since the
first and second membranes and the intermediate shear layer of this
tire together have significant hoop compression stiffness, the
interface between the connecting web or sidewall portion and the
radially inward side of the first membrane may be will necessarily
be exposed to significant shear stresses that tend to degrade or
damage the adhesive bond at the interface as the tire is rotated
under load (e.g., a large number of load cycles, etc.).
[0039] In accordance with the present invention, however, the
connecting web or sidewall portion or ply structure may extend
radially outward of the hoop structure. Alternatively, the
connecting web or sidewall portion or ply structure may extend
radially between the first and second membrane, or between the
second and third membrane, of the hoop structure. Such a
construction may be secured together by a curing step, cohesion,
and/or by adhesion. Due to the positioning of the connecting web or
sidewall portion or ply structure radially within the hoop
structure, the interfaces of the layers may not advantageously
eliminate and/or greatly mitigate damaging shear stresses incurred
by the conventional tire.
[0040] The connecting web or sidewall portion or ply structure may
be reinforced by essentially inextensible cords oriented at or near
the radial direction. The force/elongation characteristics of the
sidewall portions may be such that tensile forces produce minimal
elongation of the connecting web or sidewall portion or ply
structure, such as an increase of tension in a string may produce
minimal elongation of the string. For example, the connecting web
or sidewall portion or ply structure may a high stiffness in
tension, but very low stiffness in compression.
[0041] The connecting web or sidewall portion or ply structure may
be essentially inextensible in tension and essentially without
resistance to compression and/or buckling. Under this condition, an
externally applied load may be supported substantially by vertical
tensile forces in the connecting web or sidewall portion or ply
structure in the region above the axle without vertical tensile
forces in the region below the axle. Vertical stiffness may relate
to the ability of the tire to resist vertical deflection when under
load. A tire or assembly in accordance with the present invention
requires no pneumatic support, and therefore no air pressure
maintenance or performance loss due to sudden loss of pressure.
[0042] As shown in FIGS. 1-2, a structurally supported tire 10 in
accordance with the present invention may include a ground
contacting annular tread portion 20, a hoop structure 30 for
supporting a load on the tire, and a ply structure 60 secured to a
first axial limit of an outer radius of a rim 1 and extending
radially outward and between the hoop structure and the tread
portion and further extending radially inward from between the hoop
structure and tread portion to a second axial limit of the outer
radius of the rim. The tread portion 20 may be secured to a
radially outer surface 62 of the ply structure 60. The hoop
structure 30 may be secured to a radially inner surface 64 of the
ply structure 60. The attachment of the ply structure 60 to the rim
1 may be accomplished in a number of ways. For example, the vehicle
rim 1 may have a first clamp 3 and a second clamp 5. The first
clamp 3 may squeeze and secure a first part 65 of the ply structure
60. The second clamp 5 may squeeze and a second part 66 of the ply
structure 60.
[0043] Alternatively, the first clamp 3 may squeeze and secure both
the first part 65 of the ply structure 60 and a first ring (not
shown) thus eliminating the necessity for a first ring to be
inextensible (e.g., like conventional bead structures). The second
clamp 5 may squeeze and secure both the second part 66 of the ply
structure 60 and a second ring (not shown) thus eliminating the
necessity for the second ring to be inextensible (e.g., like
conventional bead structures). If used, the non-load bearing first
and second rings may therefore be an inexpensive material, such as
a very inexpensive polymer O-ring. Further, adhesives and
mechanical fasteners 4, 6 (e.g., bolts, etc.) may also be used to
squeeze/secure and/or supplement the attachment to the first and
second parts 65, 66 of the ply structure.
[0044] As shown in FIG. 2, the ply structure 60 may be defined by
strips 70 of material extending from the first clamp 3 radially
outward and around the hoop structure 30 and to the second clamp 5.
As described below, the strips 70 may be a layered and reinforced
ply material capable of bearing a large tensile load and very
little compressive load.
[0045] As shown in FIGS. 3-4, another structurally supported tire
110 in accordance with the present invention may include a ground
contacting annular tread portion 120, a hoop structure 130 for
supporting a load on the tire, and a ply structure 160 secured to
one axial limit of an outer radius of the rim 1 and extending
radially outward and between the hoop structure and the tread
portion and further extending radially inward from between the hoop
structure and tread portion to a second axial limit of an outer
radius of the rim. The tread portion 120 may be secured to a
radially outer surface 162 of the ply structure 160. The hoop
structure 130 may be secured to a radially inner surface 164 of the
ply structure 160. The attachment of the ply structure 160 to the
rim 1 may be accomplished in a number of ways. For example, the
vehicle rim 1 may have a first clamp 103 and a second clamp 105.
The first clamp 103 may squeeze and secure a first part 165 of the
ply structure 160. The second clamp 105 may squeeze and a second
part 166 of the ply structure 160.
[0046] Alternatively, the first clamp 103 may squeeze and secure
both the first part 165 of the ply structure 160 and a first ring
(not shown) thus eliminating the necessity for a first ring to be
inextensible (e.g., like conventional bead structures). The second
clamp 105 may squeeze and secure both the second part 166 of the
ply structure 160 and a second ring (not shown) thus eliminating
the necessity for the second ring to be inextensible (e.g., like
conventional bead structures). If used, the first and second rings
may therefore be an inexpensive material, such as a very
inexpensive polymer O-ring. Further, adhesives and mechanical
fasteners 104, 106 (e.g., bolts, etc.) may also be used to
squeeze/secure and/or supplement the attachment to the first and
second parts 165, 166 of the ply structure 160.
[0047] As shown in FIG. 4, the ply structure 160 may be defined by
strips 170 of material. One example strip 170 may extend from a
first end 172 of the strip 170 to the first clamp 103. The example
strip 170 may then be folded back over itself and extended radially
outward and around the hoop structure 130 and to the second clamp
105. The example strip 170 may then be folded back over itself and
extended radially outward beyond the hoop structure 130 and to a
second end 174 of the example strip 170. As shown in FIG. 3, a gap
176 may be defined by the ends 172, 174 of the strip 170.
Alternatively, the ply structure 160 may be constructed of one
single strip 170 of ply material leaving only a single gap 176
between the ends 172, 174 for the entire ply structure 160. As
described below, the strips 70 may be a layered and reinforced ply
material capable of bearing a large tensile load and very little
compressive load.
[0048] As described above, the tire 10 or 110 may include the hoop
structure, or shear band 30 or 130 and the ply structure 60 or 160.
The ply structure 60 or 160 may be built at a conventional bead
diameter and then stretched up over the shear band 30 or 130. The
path of the ply structure 60 or 160 may extend radially inward from
the radially outermost portion of the shear band 30 or 130. This
may allow reinforcing the ply cords to provide lateral strength to
the shear band 30 or 130 while also filling part of any gap between
the radially outer portion of the ply structure 60 or 160 and a
radially inner portion of the shear band. An angle .theta. may be
varied to adjust tension in the ply structure 60 or 160 and also
increase and/or tune lateral stiffness of the tire 10 or 110
overall. The angle .theta. may also be zero degrees or even
negative if desired (not shown). Thus, the angle .theta. provides
an important tuning parameter lacking in any conventional
structurally supported, non-pneumatic, or pneumatic tires.
[0049] A method in accordance with the present invention may
non-pneumatically support a load. The method may include the steps
of: securing a single ply structure 60, 160 to a vehicle rim 1;
clamping the single ply structure to the vehicle rim; extending the
single ply structure 60, 160 a radially outer surface 62, 162 of a
hoop structure 30, 130; further extending the single ply structure
60, 160 from the radially outer surface 62, 162 of the hoop
structure 30, 130 to the vehicle rim 1; securing the single ply
structure 60, 160 the vehicle rim 1; and supporting a load by a
compressive hoop strength of the hoop structure 30, 130 and a
tensile strength of part of the ply structure 60, 160.
[0050] The reinforced annular band or hoop structure 30, 130 may be
disposed radially inward of the tread portion 20, 120. The annular
band 30, 130 may comprise an elastomeric shear layer, a first
membrane having reinforced layers adhered to the radially innermost
extent of the elastomeric shear layer, and a second membrane having
reinforced layers adhered to the radially outermost extent of the
elastomeric shear layer. The tread portion 20, 120 may have no
grooves or may have a plurality of longitudinally oriented tread
grooves forming essentially longitudinal tread ribs therebetween.
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.
[0051] The second membrane may be offset radially inward from the
bottom of the tread groove a sufficient distance to protect the
structure of the second membrane from cuts and small penetrations
of the tread portion 20, 120. The offset distance may be increased
or decreased depending on the intended use of the tire 10, 110. For
example, a heavy truck tire may use an offset distance of about 5
mm to 7 mm.
[0052] Each of the layers of the first and second membranes may
comprise essentially inextensible reinforcing cords embedded in an
elastomeric coating. For a tire constructed of elastomeric
materials, membranes may be adhered to the shear layer by the
vulcanization of the elastomeric materials. The membranes may be
adhered to the shear layer by any other suitable method of chemical
or adhesive bonding or mechanical fixation.
[0053] The reinforcing cords of the first and second membranes may
be suitable tire belt reinforcements, such as monofilaments or
cords of steel, aramid, and/or other high modulus textiles. For
example, the reinforcing cords may be steel cords of four wires of
0.28 mm diameter (4.times.0.28). Although the reinforcing cords may
vary for each of the membranes, any suitable material may be
employed for the membranes which meets the requirements for the
tensile stiffness, bending stiffness, and compressive buckling
resistance required by the annular band. Further, the membrane
structures may be a homogeneous material, a fiber reinforced
matrix, or a layer having discrete reinforcing elements (e.g.,
short fibers, nanotubes, etc.).
[0054] In the first membrane, the layers may have essentially
parallel cords oriented at an angle relative to the tire equatorial
plane and the cords of the respective adjacent layers may have an
opposite orientation. That is, an angle +.alpha. in one layer and
an angle -.alpha. in another adjacent layer. Similarly, for the
second membrane, the layers may have essentially parallel cords
oriented at angles +.beta. and -.beta., respectively, to the
equatorial plane. Angles .alpha. and .beta. may be in the range of
about -5.degree. to about +5.degree.. Alternatively, the cords of
adjacent layers in a membrane may not be oriented at equal and
opposite angles. For example, it may be desirable for the cords of
adjacent layers to be asymmetric relative to the tire equatorial
plane. The cords of each of the layers may be embedded in an
elastomeric coating layer having a shear modulus of about 20 MPa.
The shear modulus of the coating layers may be greater than the
shear modulus of the shear layer so that the deformation of the
annular band is primarily by shear deformation within shear
layer.
[0055] As the vertical deflection of the tire increases, the
contact length, or footprint, may increase such that the
compressive stress in the second membrane exceeds its critical
buckling stress and a longitudinal buckling of the second membrane
may occur. This buckling phenomenon may cause a longitudinally
extending section of the footprint region to have reduced contact
pressure. A more uniform ground contact pressure throughout the
length of the footprint may be obtained when buckling of the
membrane is mitigated and/or avoided.
[0056] The hoop structure 30, 130 may be similar to the annular
band described above, an annular, a homogenous hoop of metal,
polymer, rubber, reinforced rubber, or fabric, and/or a multiple
layer structure of alternating steel cord plies or filament plies
and rubber shear layers as long as the hoop structure can support
the appropriate load by its compressive hoop strength. Once the
tire 10, 110 is fully constructed, the hoop structure 30, 130 may
be secured to the radially inner surface 64, 164 of the ply
structure 60, 160 by the overall structure of the tire (e.g.,
friction, mechanical constraint, etc.) or by an adhesive. This is a
departure from conventional pneumatic and non-pneumatic tires,
where a hoop structure is exclusively connected to the radially
outer surface of the connecting structure, be it plies, a
combination of pressurized air and plies, spokes, or other web
geometries. A tire 10, 110 in accordance with the present invention
may result in the interface between the hoop structure 30, 130 and
the ply structure 60, 160 being in compression 180 degrees from the
footprint (e.g., top of the tire), where the tensile ply loads are
the highest.
[0057] The material of the shear band 30, 130 may have a shear
modulus in the range of 15 MPa to 80 MPa, or 40 MPa to 60 MPa. The
shear modulus is defined using a pure shear deformation test,
recording the stress and strain, and determining the slope of the
resulting stress-strain curve. It may be desirable to maximize EI
and minimize GA. An acceptable ratio of GA/EI for a conventional
tire may be between 0.01 and 20.0. However, acceptable ratios of
GA/EI for a shear band 30, 130 in accordance with the present
invention may be 0.02 to 100.0, or between 21.0 and 100.0, or
between 1.0 and 50.0.
[0058] The tread portion 20, 120 may be secured to the radially
outer surface 62, 162 of the ply structure 60 by an adhesive. The
hoop structure 30, 130 may have a concave, or toroidal, shape
producing a curved tread portion 20, 120 as is desirable. The hoop
structure 30, 130 and ply structure 60, 160 may thereby define a
cavity 68, 168 that may or may not be open to the atmosphere and/or
unpressurized. When the tread portion 20, 120 has been suitably
worn down from use, the entire vehicle rim/tire assembly 1, 10, 110
may remain assembled while the remains of the tread portion are
ground down and replaced by a new tread portion, similar to a
conventional retreading process.
[0059] As described above, the vehicle rim 1, may have the ability
to adjust the axial distance between the clamps 3, 5, 103, 105.
Such adjustment may vary the tension and angle of the ply structure
60, 160 between the clamps 3, 5, 103, 105 and the hoop structure
30, 130 thereby altering footprint characteristics of the tire 10,
110 during rotation under load.
[0060] As shown in FIGS. 1 & 3, the adjustment mechanism 201
for the axial distance between the clamps 3, 5, 103, 105 may
include a threaded bolt 211 and four nuts 222 for varying the axial
length between two parts 235, 245 each associated with one of the
parts 65, 66 or 165, 166 of the ply structure 30, 130. The two
parts 235, 245 may or may not be part of the vehicle rim 1.
[0061] Further, suitable alternate adjustment mechanisms may also
be used. Another adjustment mechanism for the axial distance
between the clamps 3, 5, 103, 105 may include replacing the
threaded bolt 211 with a piston/cylinder assembly operatively
connected to the rotational axis of the tire 10, 110. The
piston/cylinder assembly may have a length greater than any desired
axial distance between the clamps 3, 5, 103, 105. The ends of the
piston/cylinder assembly may each threadedly engage rings for
controlling the axial distance between the clamps 3, 5, 103,
105.
[0062] Alternatively, one end of a piston/cylinder assembly may be
rotationally attached (e.g., welded, adhesive, bolted, etc.) to the
vehicle rim 1 near one of the clamps 3, 5, 103, 105 with the other
end attached to the vehicle frame. Thus, with the opposite clamp 3,
5, 103, 105 axially fixed, the axial distance may be adjusted by
engagement of the piston/cylinder assembly.
[0063] 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.
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